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Redeker KEM, Schröder S, Dücker C, Brockmöller J, Gebauer L. Targeted mutagenesis of negatively charged amino acids outlining the substrate translocation path within the human organic cation transporter 3. Biochem Pharmacol 2024; 223:116188. [PMID: 38580166 DOI: 10.1016/j.bcp.2024.116188] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2023] [Revised: 03/12/2024] [Accepted: 04/02/2024] [Indexed: 04/07/2024]
Abstract
Recently published cryo-EM structures of human organic cation transporters of the SLC22 family revealed seven, sequentially arranged glutamic and aspartic acid residues, which may be relevant for interactions with positively charged substrates. We analyzed the functional consequences of removing those negative charges by creating D155N, E232Q, D382N, E390Q, E451Q, E459Q, and D478N mutants of OCT3. E232Q, E459Q, and D478N resulted in a lack of localization in the outer cell membrane and no relevant uptake activity. However, D155N and E451Q showed a substrate-specific loss of transport activity, whereas E390Q had no remaining activity despite correct membrane localization. In contrast, D382N showed almost wild-type-like uptake. D155 is located at the entrance to the substrate binding pocket and could, therefore be involved in guiding cationic substrates towards the inside of the binding pocket. For E390, we confirm its critical function for transporter function as it was recently shown for the corresponding position in OCT1. Interestingly, E451 seems to be located at the bottom of the binding pocket in the outward-open confirmation of the transporter. Substrate-specific loss of transport activity of the E451Q variant suggests an essential role in the transport cycle of specific substances as part of an opportunistic binding site. In general, our study highlights the impact of the cryo-EM structures in guiding mutagenesis studies to understand the molecular level of transporter-ligand interactions, and it also confirms the importance of testing multiple substrates in mutagenesis studies of polyspecific OCTs.
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Affiliation(s)
- Kyra-Elisa M Redeker
- Institute of Clinical Pharmacology, University Medical Center Göttingen, D-37075 Göttingen, Germany.
| | - Sophie Schröder
- Department for Epigenetics and Systems Medicine in Neurodegenerative Diseases, German Center for Neurodegenerative Diseases (DZNE), D-37075 Göttingen, Germany
| | - Christof Dücker
- Institute of Clinical Pharmacology, University Medical Center Göttingen, D-37075 Göttingen, Germany
| | - Jürgen Brockmöller
- Institute of Clinical Pharmacology, University Medical Center Göttingen, D-37075 Göttingen, Germany
| | - Lukas Gebauer
- Institute of Clinical Pharmacology, University Medical Center Göttingen, D-37075 Göttingen, Germany
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Gilleron J, Chafik A, Lacas-Gervais S, Tanti JF, Cormont M. Golgi-associated retrograde protein (GARP) complex-dependent endosomes to trans Golgi network retrograde trafficking is controlled by Rab4b. Cell Mol Biol Lett 2024; 29:54. [PMID: 38627612 PMCID: PMC11020649 DOI: 10.1186/s11658-024-00574-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2023] [Accepted: 04/05/2024] [Indexed: 04/19/2024] Open
Abstract
BACKGROUND The trafficking of cargoes from endosomes to the trans-Golgi network requires numerous sequential and coordinated steps. Cargoes are sorted into endosomal-derived carriers that are transported, tethered, and fused to the trans-Golgi network. The tethering step requires several complexes, including the Golgi-associated retrograde protein complex, whose localization at the trans-Golgi network is determined by the activity of small GTPases of the Arl and Rab family. However, how the Golgi-associated retrograde protein complex recognizes the endosome-derived carriers that will fuse with the trans-Golgi network is still unknown. METHODS We studied the retrograde trafficking to the trans-Golgi network by using fluorescent cargoes in cells overexpressing Rab4b or after Rab4b knocked-down by small interfering RNA in combination with the downregulation of subunits of the Golgi-associated retrograde protein complex. We used immunofluorescence and image processing (Super Resolution Radial Fluctuation and 3D reconstruction) as well as biochemical approaches to characterize the consequences of these interventions on cargo carriers trafficking. RESULTS We reported that the VPS52 subunit of the Golgi-associated retrograde protein complex is an effector of Rab4b. We found that overexpression of wild type or active Rab4b increased early endosomal to trans-Golgi network retrograde trafficking of the cation-independent mannose-6-phosphate receptor in a Golgi-associated retrograde protein complex-dependent manner. Conversely, overexpression of an inactive Rab4b or Rab4b knockdown attenuated this trafficking. In the absence of Rab4b, the internalized cation-independent mannose 6 phosphate receptor did not have access to VPS52-labeled structures that look like endosomal subdomains and/or endosome-derived carriers, and whose subcellular distribution is Rab4b-independent. Consequently, the cation-independent mannose-6-phosphate receptor was blocked in early endosomes and no longer had access to the trans-Golgi network. CONCLUSION Our results support that Rab4b, by controlling the sorting of the cation-independent mannose-6-phosphate receptor towards VPS52 microdomains, confers a directional specificity for cargo carriers en route to the trans-Golgi network. Given the importance of the endocytic recycling in cell homeostasis, disruption of the Rab4b/Golgi-associated retrograde protein complex-dependent step could have serious consequences in pathologies.
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Affiliation(s)
- Jérôme Gilleron
- Université Côte d'Azur, INSERM, Mediterranean Center of Molecular Medicine (C3M), Team "Insulin Resistance in Obesity and Type 2 Diabetes", Bâtiment Archimed, 151 Route de Saint Antoine de Ginestière, BP 2 3194, 06200, Nice Cedex 03, France.
| | - Abderrahman Chafik
- Université Côte d'Azur, INSERM, Mediterranean Center of Molecular Medicine (C3M), Team "Insulin Resistance in Obesity and Type 2 Diabetes", Bâtiment Archimed, 151 Route de Saint Antoine de Ginestière, BP 2 3194, 06200, Nice Cedex 03, France
| | - Sandra Lacas-Gervais
- Université Côte d'Azur, CCMA, Centre Commun de Microscopie Appliquée (CCMA), Nice, France
| | - Jean-François Tanti
- Université Côte d'Azur, INSERM, Mediterranean Center of Molecular Medicine (C3M), Team "Insulin Resistance in Obesity and Type 2 Diabetes", Bâtiment Archimed, 151 Route de Saint Antoine de Ginestière, BP 2 3194, 06200, Nice Cedex 03, France
| | - Mireille Cormont
- Université Côte d'Azur, INSERM, Mediterranean Center of Molecular Medicine (C3M), Team "Insulin Resistance in Obesity and Type 2 Diabetes", Bâtiment Archimed, 151 Route de Saint Antoine de Ginestière, BP 2 3194, 06200, Nice Cedex 03, France.
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Lian S, Chen Y, Zhou Y, Feng T, Chen J, Liang L, Qian Y, Huang T, Zhang C, Wu F, Zou W, Li Z, Meng L, Li M. Functional differentiation and genetic diversity of rice cation exchanger (CAX) genes and their potential use in rice improvement. Sci Rep 2024; 14:8642. [PMID: 38622172 PMCID: PMC11018787 DOI: 10.1038/s41598-024-58224-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2024] [Accepted: 03/26/2024] [Indexed: 04/17/2024] Open
Abstract
Cation exchanger (CAX) genes play an important role in plant growth/development and response to biotic and abiotic stresses. Here, we tried to obtain important information on the functionalities and phenotypic effects of CAX gene family by systematic analyses of their expression patterns, genetic diversity (gene CDS haplotypes, structural variations, gene presence/absence variations) in 3010 rice genomes and nine parents of 496 Huanghuazhan introgression lines, the frequency shifts of the predominant gcHaps at these loci to artificial selection during modern breeding, and their association with tolerances to several abiotic stresses. Significant amounts of variation also exist in the cis-regulatory elements (CREs) of the OsCAX gene promoters in 50 high-quality rice genomes. The functional differentiation of OsCAX gene family were reflected primarily by their tissue and development specific expression patterns and in varied responses to different treatments, by unique sets of CREs in their promoters and their associations with specific agronomic traits/abiotic stress tolerances. Our results indicated that OsCAX1a and OsCAX2 as general signal transporters were in many processes of rice growth/development and responses to diverse environments, but they might be of less value in rice improvement. OsCAX1b, OsCAX1c, OsCAX3 and OsCAX4 was expected to be of potential value in rice improvement because of their associations with specific traits, responsiveness to specific abiotic stresses or phytohormones, and relatively high gcHap and CRE diversity. Our strategy was demonstrated to be highly efficient to obtain important genetic information on genes/alleles of specific gene family and can be used to systematically characterize the other rice gene families.
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Affiliation(s)
- Shangshu Lian
- School of Agronomy, Anhui Agricultural University, Hefei, 230036, China
- Shenzhen Branch, Guangdong Laboratory of Lingnan Modern Agriculture, Genome Analysis Laboratory of the Ministry of Agriculture and Rural Affairs, Agricultural Genomics Institute at Shenzhen, Chinese Academy of Agricultural Sciences, Shenzhen, 518120, China
| | - Yanjun Chen
- School of Agronomy, Anhui Agricultural University, Hefei, 230036, China
| | - Yanyan Zhou
- School of Agronomy, Anhui Agricultural University, Hefei, 230036, China
| | - Ting Feng
- School of Agronomy, Anhui Agricultural University, Hefei, 230036, China
| | - Jingsi Chen
- School of Agronomy, Anhui Agricultural University, Hefei, 230036, China
| | - Lunping Liang
- School of Agronomy, Anhui Agricultural University, Hefei, 230036, China
| | - Yingzhi Qian
- School of Agronomy, Anhui Agricultural University, Hefei, 230036, China
| | - Tao Huang
- School of Agronomy, Anhui Agricultural University, Hefei, 230036, China
| | - Chenyang Zhang
- School of Agronomy, Anhui Agricultural University, Hefei, 230036, China
| | - Fengcai Wu
- School of Agronomy, Anhui Agricultural University, Hefei, 230036, China
| | - Wenli Zou
- Shenzhen Branch, Guangdong Laboratory of Lingnan Modern Agriculture, Genome Analysis Laboratory of the Ministry of Agriculture and Rural Affairs, Agricultural Genomics Institute at Shenzhen, Chinese Academy of Agricultural Sciences, Shenzhen, 518120, China
| | - Zhikang Li
- School of Agronomy, Anhui Agricultural University, Hefei, 230036, China
- Shenzhen Branch, Guangdong Laboratory of Lingnan Modern Agriculture, Genome Analysis Laboratory of the Ministry of Agriculture and Rural Affairs, Agricultural Genomics Institute at Shenzhen, Chinese Academy of Agricultural Sciences, Shenzhen, 518120, China
| | - Lijun Meng
- Shenzhen Branch, Guangdong Laboratory of Lingnan Modern Agriculture, Genome Analysis Laboratory of the Ministry of Agriculture and Rural Affairs, Agricultural Genomics Institute at Shenzhen, Chinese Academy of Agricultural Sciences, Shenzhen, 518120, China.
| | - Min Li
- School of Agronomy, Anhui Agricultural University, Hefei, 230036, China.
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Picazo I, Espeso EA. Interconnections between the Cation/Alkaline pH-Responsive Slt and the Ambient pH Response of PacC/Pal Pathways in Aspergillus nidulans. Cells 2024; 13:651. [PMID: 38607089 PMCID: PMC11011638 DOI: 10.3390/cells13070651] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2024] [Revised: 03/21/2024] [Accepted: 04/05/2024] [Indexed: 04/13/2024] Open
Abstract
In the filamentous ascomycete Aspergillus nidulans, at least three high hierarchy transcription factors are required for growth at extracellular alkaline pH: SltA, PacC and CrzA. Transcriptomic profiles depending on alkaline pH and SltA function showed that pacC expression might be under SltA regulation. Additional transcriptional studies of PacC and the only pH-regulated pal gene, palF, confirmed both the strong dependence on ambient pH and the function of SltA. The regulation of pacC expression is dependent on the activity of the zinc binuclear (C6) cluster transcription factor PacX. However, we found that the ablation of sltA in the pacX- mutant background specifically prevents the increase in pacC expression levels without affecting PacC protein levels, showing a novel specific function of the PacX factor. The loss of sltA function causes the anomalous proteolytic processing of PacC and a reduction in the post-translational modifications of PalF. At alkaline pH, in a null sltA background, PacC72kDa accumulates, detection of the intermediate PacC53kDa form is extremely low and the final processed form of 27 kDa shows altered electrophoretic mobility. Constitutive ubiquitination of PalF or the presence of alkalinity-mimicking mutations in pacC, such as pacCc14 and pacCc700, resembling PacC53kDa and PacC27kDa, respectively, allowed the normal processing of PacC but did not rescue the alkaline pH-sensitive phenotype caused by the null sltA allele. Overall, data show that Slt and PacC/Pal pathways are interconnected, but the transcription factor SltA is on a higher hierarchical level than PacC on regulating the tolerance to the ambient alkalinity in A. nidulans.
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Affiliation(s)
| | - Eduardo A. Espeso
- Department of Molecular and Cellular Biology, Centro de Investigaciones Biológicas (CIB) Margarita Salas, Spanish Research Council (CSIC), Ramiro de Maeztu, 9, 28040 Madrid, Spain;
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Nordenskiöld L, Shi X, Korolev N, Zhao L, Zhai Z, Lindman B. Liquid-liquid phase separation (LLPS) in DNA and chromatin systems from the perspective of colloid physical chemistry. Adv Colloid Interface Sci 2024; 326:103133. [PMID: 38547652 DOI: 10.1016/j.cis.2024.103133] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2023] [Accepted: 03/11/2024] [Indexed: 04/13/2024]
Abstract
DNA is a highly charged polyelectrolyte and is prone to associative phase separation driven by the presence of multivalent cations, charged surfactants, proteins, polymers and colloids. The process of DNA phase separation induced by positively charged species is often called DNA condensation. Generally, it refers to either intramolecular DNA compaction (coil-globule transition) or intermolecular DNA aggregation with macroscopic phase separation, but the formation of a DNA liquid crystalline system is also displayed. This has traditionally been described by polyelectrolyte theory and qualitative (Flory-Huggins-based) polymer theory approaches. DNA in the cell nucleus is packed into chromatin wound around the histone octamer (a protein complex comprising two copies each of the four histone proteins H2A, H2B, H3 and H4) to form nucleosomes separated by linker DNA. During the last decade, the phenomenon of the formation of biomolecular condensates (dynamic droplets) by liquid-liquid phase separation (LLPS) has emerged as a generally important mechanism for the formation of membraneless organelles from proteins, nucleic acids and their complexes. DNA and chromatin droplet formation through LLPS has recently received much attention by in vitro as well as in vivo studies that established the importance of this for compartmentalisation in the cell nucleus. Here, we review DNA and chromatin LLPS from a general colloid physical chemistry perspective. We start with a general discussion of colloidal phase separation in aqueous solutions and review the original (pre-LLPS era) work on DNA (macroscopic) phase separation for simpler systems with DNA in the presence of multivalent cations and well-defined surfactants and colloids. Following that, we discuss and illustrate the similarities of such macroscopic phase separation with the general behaviour of LLPS droplet formation by associative phase separation for DNA-protein systems, including chromatin; we also note cases of segregative association. The review ends with a discussion of chromatin LLPS in vivo and its physiological significance.
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Affiliation(s)
- Lars Nordenskiöld
- School of Biological Sciences, Nanyang Technological University, Singapore 637551, Singapore.
| | - Xiangyan Shi
- Department of Biology, Shenzhen MSU-BIT University, Shenzhen 518172, China.
| | - Nikolay Korolev
- School of Biological Sciences, Nanyang Technological University, Singapore 637551, Singapore
| | - Lei Zhao
- Department of Biology, Shenzhen MSU-BIT University, Shenzhen 518172, China
| | - Ziwei Zhai
- Department of Biology, Shenzhen MSU-BIT University, Shenzhen 518172, China
| | - Björn Lindman
- School of Biological Sciences, Nanyang Technological University, Singapore 637551, Singapore; Physical Chemistry, University of Lund, P.O. Box 124, S-221 00 Lund, Sweden; Coimbra Chemistry Centre, Department of Chemistry, University of Coimbra, Rua Larga, 3004-535 Coimbra, Portugal.
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6
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Aditya L, Vu HP, Johir MAH, Mao S, Ansari A, Fu Q, Nghiem LD. Synthesizing cationic polymers and tuning their properties for microalgae harvesting. Sci Total Environ 2024; 917:170423. [PMID: 38281644 DOI: 10.1016/j.scitotenv.2024.170423] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/27/2023] [Revised: 01/09/2024] [Accepted: 01/23/2024] [Indexed: 01/30/2024]
Abstract
This study reports a facile technique to synthesize and tune the cationic polymer, poly(3-acrylamidopropyl)trimethylammonium chloride (PAPTAC), in terms of molecular weight and surface change for harvesting three microalgae species (Scenedesmus sp., P.purpureum, and C. vulgaris). The PAPTAC polymer was synthesised by UV-induced free-radical polymerisation. Polymer tuning was demonstrated by regulating the monomer concentration (60 to 360 mg/mL) and UV power (36 and 60 W) for polymerisation. The obtained PAPTAC polymer was evaluated for harvesting three different microalgae species and compared to a commercially available polymer. The highest flocculation efficiency for Scenedesmus sp. and P. purpureum was observed at a dosage of 25 mg-polymer/g of dry biomass by using PAPTAC-90, resulting in higher flocculation efficiency than the commercial polymer. Results in this study show evidence of effective neutralisation of the negative charge surface of microalgae cells by the produced cationic PAPTAC polymer and polymer bridging for effective flocculation. The obtained PAPTAC polymer was less effective for harvesting C. vulgaris, possibly due to other factors such as cell morphology and composition of extracellular polymeric substances of at the cell membrane that may also influence harvesting performance.
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Affiliation(s)
- Lisa Aditya
- Centre for Technology in Water and Wastewater, School of Civil and Environmental Engineering, University of Technology Sydney, NSW 2220, Australia
| | - Hang P Vu
- Centre for Technology in Water and Wastewater, School of Civil and Environmental Engineering, University of Technology Sydney, NSW 2220, Australia
| | - Md Abu Hasan Johir
- Centre for Technology in Water and Wastewater, School of Civil and Environmental Engineering, University of Technology Sydney, NSW 2220, Australia
| | - Shudi Mao
- Centre for Technology in Water and Wastewater, School of Civil and Environmental Engineering, University of Technology Sydney, NSW 2220, Australia
| | - Ashley Ansari
- Centre for Technology in Water and Wastewater, School of Civil and Environmental Engineering, University of Technology Sydney, NSW 2220, Australia
| | - Qiang Fu
- Centre for Technology in Water and Wastewater, School of Civil and Environmental Engineering, University of Technology Sydney, NSW 2220, Australia.
| | - Long D Nghiem
- Centre for Technology in Water and Wastewater, School of Civil and Environmental Engineering, University of Technology Sydney, NSW 2220, Australia.
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Schulz V, Galea D, Herzberg M, Nies DH. Protecting the Achilles heel: three FolE_I-type GTP-cyclohydrolases needed for full growth of metal-resistant Cupriavidus metallidurans under a variety of conditions. J Bacteriol 2024; 206:e0039523. [PMID: 38226602 PMCID: PMC10882993 DOI: 10.1128/jb.00395-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2023] [Accepted: 12/15/2023] [Indexed: 01/17/2024] Open
Abstract
In Cupriavidus metallidurans and other bacteria, biosynthesis of the essential biochemical cofactor tetrahydrofolate (THF) initiates from guanosine triphosphate (GTP). This step is catalyzed by FolE_I-type GTP cyclohydrolases, which are either zinc-dependent FolE_IA-type or metal-promiscuous FolE_IB-type enzymes. As THF is also essential for GTP biosynthesis, GTP and THF synthesis form a cooperative cycle, which may be influenced by the cellular homeostasis of zinc and other metal cations. Metal-resistant C. metallidurans harbors one FolE_IA-type and two FolE_IB-type enzymes. All three proteins were produced in Escherichia coli. FolE_IA was indeed zinc dependent and the two FolE_IB enzymes metal-promiscuous GTP cyclohydrolases in vitro, the latter, for example, functioning with iron, manganese, or cobalt. Single and double mutants of C. metallidurans with deletions in the folE_I genes were constructed to analyze the contribution of the individual FolE_I-type enzymes under various conditions. FolE_IA was required in the presence of cadmium, hydrogen peroxide, metal chelators, and under general metal starvation conditions. FolE_IB1 was important when zinc uptake was impaired in cells without the zinc importer ZupT (ZIP family) and in the presence of trimethoprim, an inhibitor of THF biosynthesis. FolE_IB2 was needed under conditions of low zinc and cobalt but high magnesium availability. Together, these data demonstrate that C. metallidurans requires all three enzymes to allow efficient growth under a variety of conditions.IMPORTANCETetrahydrofolate (THF) is an important cofactor in microbial biochemistry. This "Achilles heel" of metabolism has been exploited by anti-metabolites and antibiotics such as sulfonamide and trimethoprim. Since THF is essential for the synthesis of guanosine triphosphate (GTP) and THF biosynthesis starts from GTP, synthesis of both compounds forms a cooperative cycle. The first step of THF synthesis by GTP cyclohydrolases (FolEs) is metal dependent and catalyzed by zinc- or metal-promiscuous enzymes, so that the cooperative THF and GTP synthesis cycle may be influenced by the homeostasis of several metal cations, especially that of zinc. The metal-resistant bacterium C. metallidurans needs three FolEs to grow in environments with both high and low zinc and cadmium content. Consequently, bacterial metal homeostasis is required to guarantee THF biosynthesis.
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Affiliation(s)
- Vladislava Schulz
- Molecular Microbiology, Martin-Luther-University Halle-Wittenberg, Halle/Saale, Germany
| | - Diana Galea
- Molecular Microbiology, Martin-Luther-University Halle-Wittenberg, Halle/Saale, Germany
| | - Martin Herzberg
- Department of Analytical Chemistry, Helmholtz Centre for Environmental Research – UFZ, Leipzig, Germany
| | - Dietrich H. Nies
- Molecular Microbiology, Martin-Luther-University Halle-Wittenberg, Halle/Saale, Germany
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Mom R, Réty S, Mocquet V, Auguin D. Deciphering Molecular Mechanisms Involved in the Modulation of Human Aquaporins' Water Permeability by Zinc Cations: A Molecular Dynamics Approach. Int J Mol Sci 2024; 25:2267. [PMID: 38396944 PMCID: PMC10888569 DOI: 10.3390/ijms25042267] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2024] [Revised: 02/03/2024] [Accepted: 02/05/2024] [Indexed: 02/25/2024] Open
Abstract
Aquaporins (AQPs) constitute a wide family of water channels implicated in all kind of physiological processes. Zinc is the second most abundant trace element in the human body and a few studies have highlighted regulation of AQP0 and AQP4 by zinc. In the present work, we addressed the putative regulation of AQPs by zinc cations in silico through molecular dynamics simulations of human AQP0, AQP2, AQP4, and AQP5. Our results align with other scales of study and several in vitro techniques, hence strengthening the reliability of this regulation by zinc. We also described two distinct putative molecular mechanisms associated with the increase or decrease in AQPs' water permeability after zinc binding. In association with other studies, our work will help deciphering the interaction networks existing between zinc and channel proteins.
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Affiliation(s)
- Robin Mom
- Laboratoire de Biologie et Modélisation de la Cellule, ENS de Lyon, Université Claude Bernard, CNRS UMR 5239, INSERM U1293, 46 Allée d’Italie Site Jacques Monod, F-69007 Lyon, France; (S.R.); (V.M.)
- Research Group on Vestibular Pathophysiology, CNRS, Unit GDR2074, F-13331 Marseille, France
| | - Stéphane Réty
- Laboratoire de Biologie et Modélisation de la Cellule, ENS de Lyon, Université Claude Bernard, CNRS UMR 5239, INSERM U1293, 46 Allée d’Italie Site Jacques Monod, F-69007 Lyon, France; (S.R.); (V.M.)
| | - Vincent Mocquet
- Laboratoire de Biologie et Modélisation de la Cellule, ENS de Lyon, Université Claude Bernard, CNRS UMR 5239, INSERM U1293, 46 Allée d’Italie Site Jacques Monod, F-69007 Lyon, France; (S.R.); (V.M.)
| | - Daniel Auguin
- Laboratoire de Physiologie, Ecologie et Environnement (P2E), UPRES EA 1207/USC INRAE-1328, UFR Sciences et Techniques, Université d’Orléans, F-45067 Orléans, France
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Mei Y, Shen Y. Cation-π Interactions Greatly Influence Ion Transportability of the Light-Driven Sodium Pump KR2: A Molecular Dynamics Study. J Chem Inf Model 2024; 64:974-982. [PMID: 38237560 DOI: 10.1021/acs.jcim.3c01883] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/13/2024]
Abstract
Krokinobacter eikastus rhodopsin 2 (KR2) is a typical light-driven sodium pump. Although wild-type KR2 exhibits high Na+ selectivity, mutagenesis performed on the residues constituting the entrance enables permeation of K+ and Cs+, while the underlying mechanism remains elusive. This study presents a comprehensive molecular dynamics investigation, including force field optimization, metadynamics, and alchemical free energy methods, to explore the N61L/G263F mutant of KR2, which exhibits transportability for K+ and Cs+. The introduced Phe263 residue can directly promote ion binding at the entrance through cation-π interactions, while the N61L mutation can enhance ion binding at Phe46 by relieving steric hindrance. These results suggest that cation-π interactions may significantly influence the ion transportability and selectivity of KR2, which can provide important insights for protein engineering and the design of artificial ion transporters.
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Affiliation(s)
- Yunhao Mei
- School of Chemistry, IGCME, Sun Yat-sen University, Guangzhou 510006, China
| | - Yong Shen
- School of Chemistry, IGCME, Sun Yat-sen University, Guangzhou 510006, China
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Liu J, Li D, Wang J, Wang Q, Guo X, Fu Q, Kear P, Zhu G, Yang X. Genome-wide characterization of the CPA gene family in potato and a preliminary functional analysis of its role in NaCl tolerance. BMC Genomics 2024; 25:144. [PMID: 38317113 PMCID: PMC10840148 DOI: 10.1186/s12864-024-10000-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2023] [Accepted: 01/09/2024] [Indexed: 02/07/2024] Open
Abstract
BACKGROUND The cation/proton antiporter (CPA) superfamily plays a crucial role in regulating ion homeostasis and pH in plant cells, contributing to stress resistance. However, in potato (Solanum tuberosum L.), systematic identification and analysis of CPA genes are lacking. RESULTS A total of 33 StCPA members were identified and classified into StNHX (n = 7), StKEA (n = 6), and StCHX (n = 20) subfamilies. StCHX owned the highest number of conserved motifs, followed by StKEA and StNHX. The StNHX and StKEA subfamilies owned more exons than StCHX. NaCl stress induced the differentially expression of 19 genes in roots or leaves, among which StCHX14 and StCHX16 were specifically induced in leaves, while StCHX2 and StCHX19 were specifically expressed in the roots. A total of 11 strongly responded genes were further verified by qPCR. Six CPA family members, StNHX1, StNHX2, StNHX3, StNHX5, StNHX6 and StCHX19, were proved to transport Na+ through yeast complementation experiments. CONCLUSIONS This study provides comprehensive insights into StCPAs and their response to NaCl stress, facilitating further functional characterization.
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Affiliation(s)
- Jintao Liu
- Key Lab for Potato Biology in Universities of Yunnan, School of Life Sciences, Yunnan Normal University, Kunming, 650500, China
- Southwest United Graduate School, Kunming, 650500, China
| | - Dianjue Li
- Key Lab for Potato Biology in Universities of Yunnan, School of Life Sciences, Yunnan Normal University, Kunming, 650500, China
| | - Jing Wang
- Key Lab for Potato Biology in Universities of Yunnan, School of Life Sciences, Yunnan Normal University, Kunming, 650500, China
| | - Qian Wang
- Key Lab for Potato Biology in Universities of Yunnan, School of Life Sciences, Yunnan Normal University, Kunming, 650500, China
| | - Xiao Guo
- Institute of Vegetables, Shandong Academy of Agricultural Sciences/Molecular Biology Key Laboratory of Shandong Facility Vegetable/National Vegetable Improvement Center Shandong Sub-Center, Jinan, 250100, China
| | - Qi Fu
- Key Lab for Potato Biology in Universities of Yunnan, School of Life Sciences, Yunnan Normal University, Kunming, 650500, China
| | - Philip Kear
- International Potato Center (CIP), CIP China Center for Asia Pacific, Beijing, 100081, China
| | - Guangtao Zhu
- Key Lab for Potato Biology in Universities of Yunnan, School of Life Sciences, Yunnan Normal University, Kunming, 650500, China.
- Southwest United Graduate School, Kunming, 650500, China.
| | - Xiaohui Yang
- Institute of Vegetables, Shandong Academy of Agricultural Sciences/Molecular Biology Key Laboratory of Shandong Facility Vegetable/National Vegetable Improvement Center Shandong Sub-Center, Jinan, 250100, China.
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11
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Allard J, Bucher S, Ferron PJ, Launay Y, Fromenty B. Busulfan induces steatosis in HepaRG cells but not in primary human hepatocytes: Possible explanations and implication for the prediction of drug-induced liver injury. Fundam Clin Pharmacol 2024; 38:152-167. [PMID: 37665028 DOI: 10.1111/fcp.12951] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2023] [Revised: 07/27/2023] [Accepted: 08/10/2023] [Indexed: 09/05/2023]
Abstract
BACKGROUND The antineoplastic drug busulfan can induce different hepatic lesions including cholestasis and sinusoidal obstruction syndrome. However, hepatic steatosis has never been reported in patients. OBJECTIVES This study aimed to determine whether busulfan could induce steatosis in primary human hepatocytes (PHH) and differentiated HepaRG cells. METHODS Neutral lipids were determined in PHH and HepaRG cells. Mechanistic investigations were performed in HepaRG cells by measuring metabolic fluxes linked to lipid homeostasis, reduced glutathione (GSH) levels, and expression of genes involved in lipid metabolism and endoplasmic reticulum (ER) stress. Analysis of two previous transcriptomic datasets was carried out. RESULTS Busulfan induced lipid accumulation in HepaRG cells but not in six different batches of PHH. In HepaRG cells, busulfan impaired VLDL secretion, increased fatty acid uptake, and induced ER stress. Transcriptomic data analysis and decreased GSH levels suggested that busulfan-induced steatosis might be linked to the high expression of glutathione S-transferase (GST) isoenzyme A1, which is responsible for the formation of the hepatotoxic sulfonium cation conjugate. In keeping with this, the GST inhibitor ethacrynic acid and the chemical chaperone tauroursodeoxycholic acid alleviated busulfan-induced lipid accumulation in HepaRG cells supporting the role of the sulfonium cation conjugate and ER stress in steatosis. CONCLUSION While the HepaRG cell line is an invaluable tool for pharmacotoxicological studies, it might not be always an appropriate model to predict and mechanistically investigate drug-induced liver injury. Hence, we recommend carrying out toxicological investigations in both HepaRG cells and PHH to avoid drawing wrong conclusions on the potential hepatotoxicity of drugs and other xenobiotics.
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Affiliation(s)
- Julien Allard
- Division of Molecular and Systems Toxicology, Department of Pharmaceutical Sciences, University of Basel, Basel, Switzerland
| | | | - Pierre-Jean Ferron
- INSERM, Univ Rennes, INRAE, Institut NUMECAN (Nutrition Metabolisms and Cancer) UMR_A 1341, UMR_S 1317, Rennes, France
| | - Youenn Launay
- INSERM, Univ Rennes, INRAE, Institut NUMECAN (Nutrition Metabolisms and Cancer) UMR_A 1341, UMR_S 1317, Rennes, France
| | - Bernard Fromenty
- INSERM, Univ Rennes, INRAE, Institut NUMECAN (Nutrition Metabolisms and Cancer) UMR_A 1341, UMR_S 1317, Rennes, France
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12
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Ahmed J, Ismail A, Ding L, Yool AJ, Chaumont F. A new method to measure aquaporin-facilitated membrane diffusion of hydrogen peroxide and cations in plant suspension cells. Plant Cell Environ 2024; 47:527-539. [PMID: 37946673 DOI: 10.1111/pce.14763] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/19/2023] [Revised: 10/03/2023] [Accepted: 10/31/2023] [Indexed: 11/12/2023]
Abstract
Plant aquaporins (AQPs) facilitate the membrane diffusion of water and small solutes, including hydrogen peroxide (H2 O2 ) and, possibly, cations, essential signalling molecules in many physiological processes. While the determination of the channel activity generally depends on heterologous expression of AQPs in Xenopus oocytes or yeast cells, we established a genetic tool to determine whether they facilitate the diffusion of H2 O2 through the plasma membrane in living plant cells. We designed genetic constructs to co-express the fluorescent H2 O2 sensor HyPer and AQPs, with expression controlled by a heat shock-inducible promoter in Nicotiana tabacum BY-2 suspension cells. After induction of ZmPIP2;5 AQP expression, a HyPer signal was recorded when the cells were incubated with H2 O2 , suggesting that ZmPIP2;5 facilitates H2 O2 transmembrane diffusion; in contrast, the ZmPIP2;5W85A mutated protein was inactive as a water or H2 O2 channel. ZmPIP2;1, ZmPIP2;4 and AtPIP2;1 also facilitated H2 O2 diffusion. Incubation with abscisic acid and the elicitor flg22 peptide induced the intracellular H2 O2 accumulation in BY-2 cells expressing ZmPIP2;5. We also monitored cation channel activity of ZmPIP2;5 using a novel fluorescent photo-switchable Li+ sensor in BY-2 cells. BY-2 suspension cells engineered for inducible expression of AQPs as well as HyPer expression and the use of Li+ sensors constitute a powerful toolkit for evaluating the transport activity and the molecular determinants of PIPs in living plant cells.
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Affiliation(s)
- Jahed Ahmed
- Louvain Institute of Biomolecular Science and Technology, UCLouvain, Louvain-la-Neuve, Belgium
| | - Ahmed Ismail
- Louvain Institute of Biomolecular Science and Technology, UCLouvain, Louvain-la-Neuve, Belgium
- Department of Horticulture, Faculty of Agriculture, Damanhour University, Damanhour, Egypt
| | - Lei Ding
- Louvain Institute of Biomolecular Science and Technology, UCLouvain, Louvain-la-Neuve, Belgium
| | - Andrea J Yool
- School of Biomedicine, Institute for Photonics and Advanced Sensing (IPAS), University of Adelaide, Adelaide, Australia
| | - François Chaumont
- Louvain Institute of Biomolecular Science and Technology, UCLouvain, Louvain-la-Neuve, Belgium
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13
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Niloy SI, Strege PR, Hannan EC, Cowan LM, Linsenmeier F, Friedrich O, Farrugia G, Beyder A. Stretch response of the mechano-gated channel TMEM63A in membrane patches and single cells. Am J Physiol Cell Physiol 2024; 326:C622-C631. [PMID: 38189136 DOI: 10.1152/ajpcell.00583.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2023] [Revised: 12/20/2023] [Accepted: 12/22/2023] [Indexed: 01/09/2024]
Abstract
The recently discovered ion channel TMEM63A has biophysical features distinctive for mechano-gated cation channels, activating at high pressures with slow kinetics while not inactivating. However, some biophysical properties are less clear, including no information on its function in whole cells. The aim of this study is to expand the TMEM63A biophysical characterization and examine the function in whole cells. Piezo1-knockout HEK293T cells were cotransfected with human TMEM63A and green fluorescent protein (GFP), and macroscopic currents in cell-attached patches were recorded by high-speed pressure clamp at holding voltages from -120 to -20 mV with 0-100 mmHg patch suction for 1 s. HEK293 cells cotransfected with TMEM63A and GCaMP5 were seeded onto polydimethylsiloxane (PDMS) membrane, and the response to 3-12 s of 1%-15% whole cell isotropic (equi-biaxial) stretch induced by an IsoStretcher was measured by the change in intracellular calcium ([Ca2+]i) and presented as (ΔF/F0 > 1). Increasing patch pressures activated TMEM63A currents with accelerating activation kinetics and current amplitudes that were pressure dependent but voltage independent. TMEM63A currents were plateaued within 2 s, recovered quickly, and were sensitive to Gd3+. In whole cells stretched on flexible membranes, radial stretch increased the [Ca2+]i responses in a larger proportion of cells cotransfected with TMEM63A and GCaMP5 than GCaMP5-only controls. TMEM63A currents are force activated and voltage insensitive, have a high threshold for pressure activation with slow activation and deactivation, and lack inactivation over 5 s. TMEM63A has the net polarity and kinetics that would depolarize plasma membranes and increase inward currents, contributing to a sustained [Ca2+]i increase in response to high stretch.NEW & NOTEWORTHY TMEM63A has biophysical features distinctive for mechano-gated cation channels, but some properties are less clear, including no functional information in whole cells. We report that pressure-dependent yet voltage-independent TMEM63A currents in cell membrane patches correlated with cell size. In addition, radial stretch of whole cells on flexible membranes increased the [Ca2+]i responses more in TMEM63A-transfected cells. Inward TMEM63A currents in response to high stretch can depolarize plasma membranes and contribute to a sustained [Ca2+]i increase.
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Affiliation(s)
- Sayeman Islam Niloy
- Enteric Neuroscience Program (ENSP), Division of Gastroenterology and Hepatology, Mayo Clinic, Rochester, Minnesota, United States
| | - Peter R Strege
- Enteric Neuroscience Program (ENSP), Division of Gastroenterology and Hepatology, Mayo Clinic, Rochester, Minnesota, United States
- Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, Minnesota, United States
| | - Elizabeth C Hannan
- Enteric Neuroscience Program (ENSP), Division of Gastroenterology and Hepatology, Mayo Clinic, Rochester, Minnesota, United States
| | - Luke M Cowan
- Enteric Neuroscience Program (ENSP), Division of Gastroenterology and Hepatology, Mayo Clinic, Rochester, Minnesota, United States
| | - Fabian Linsenmeier
- Institute of Medical Biotechnology, Department of Chemical and Biological Engineering, Friedrich-Alexander University Erlangen-Nürnberg, Erlangen, Germany
| | - Oliver Friedrich
- Institute of Medical Biotechnology, Department of Chemical and Biological Engineering, Friedrich-Alexander University Erlangen-Nürnberg, Erlangen, Germany
| | - Gianrico Farrugia
- Enteric Neuroscience Program (ENSP), Division of Gastroenterology and Hepatology, Mayo Clinic, Rochester, Minnesota, United States
- Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, Minnesota, United States
| | - Arthur Beyder
- Enteric Neuroscience Program (ENSP), Division of Gastroenterology and Hepatology, Mayo Clinic, Rochester, Minnesota, United States
- Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, Minnesota, United States
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14
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Mathew IE, Rhein HS, Yang J, Gradogna A, Carpaneto A, Guo Q, Tappero R, Scholz-Starke J, Barkla BJ, Hirschi KD, Punshon T. Sequential removal of cation/H + exchangers reveals their additive role in elemental distribution, calcium depletion and anoxia tolerance. Plant Cell Environ 2024; 47:557-573. [PMID: 37916653 DOI: 10.1111/pce.14756] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/20/2023] [Revised: 09/21/2023] [Accepted: 10/18/2023] [Indexed: 11/03/2023]
Abstract
Multiple Arabidopsis H+ /Cation exchangers (CAXs) participate in high-capacity transport into the vacuole. Previous studies have analysed single and double mutants that marginally reduced transport; however, assessing phenotypes caused by transport loss has proven enigmatic. Here, we generated quadruple mutants (cax1-4: qKO) that exhibited growth inhibition, an 85% reduction in tonoplast-localised H+ /Ca transport, and enhanced tolerance to anoxic conditions compared to CAX1 mutants. Leveraging inductively coupled plasma mass spectrometry (ICP-MS) and synchrotron X-ray fluorescence (SXRF), we demonstrate CAX transporters work together to regulate leaf elemental content: ICP-MS analysis showed that the elemental concentrations in leaves strongly correlated with the number of CAX mutations; SXRF imaging showed changes in element partitioning not present in single CAX mutants and qKO had a 40% reduction in calcium (Ca) abundance. Reduced endogenous Ca may promote anoxia tolerance; wild-type plants grown in Ca-limited conditions were anoxia tolerant. Sequential reduction of CAXs increased mRNA expression and protein abundance changes associated with reactive oxygen species and stress signalling pathways. Multiple CAXs participate in postanoxia recovery as their concerted removal heightened changes in postanoxia Ca signalling. This work showcases the integrated and diverse function of H+ /Cation transporters and demonstrates the ability to improve anoxia tolerance through diminishing endogenous Ca levels.
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Affiliation(s)
- Iny Elizebeth Mathew
- Pediatrics-Nutrition, Children's Nutrition Research, Baylor College of Medicine, Houston, Texas, USA
| | - Hormat Shadgou Rhein
- Pediatrics-Nutrition, Children's Nutrition Research, Baylor College of Medicine, Houston, Texas, USA
| | - Jian Yang
- Pediatrics-Nutrition, Children's Nutrition Research, Baylor College of Medicine, Houston, Texas, USA
| | - Antonella Gradogna
- Institute of Biophysics, Consiglio Nazionale delle Ricerche, Genova, Italy
| | - Armando Carpaneto
- Institute of Biophysics, Consiglio Nazionale delle Ricerche, Genova, Italy
- Department of Earth, Environment and Life Sciences (DISTAV), University of Genoa, Genova, Italy
| | - Qi Guo
- Faculty of Science and Engineering, Southern Cross University, Lismore, New South Wales, Australia
| | - Ryan Tappero
- Brookhaven National Laboratory, Photon Sciences Department, Upton, New York, USA
| | | | - Bronwyn J Barkla
- Faculty of Science and Engineering, Southern Cross University, Lismore, New South Wales, Australia
| | - Kendal D Hirschi
- Pediatrics-Nutrition, Children's Nutrition Research, Baylor College of Medicine, Houston, Texas, USA
| | - Tracy Punshon
- Department of Biological Sciences, Dartmouth College, Hanover, New Hampshire, USA
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15
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Pochini L, Barone F, Console L, Brunocilla C, Galluccio M, Scalise M, Indiveri C. OCTN1 (SLC22A4) displays two different transport pathways for organic cations or zwitterions. Biochim Biophys Acta Biomembr 2024; 1866:184263. [PMID: 38092232 DOI: 10.1016/j.bbamem.2023.184263] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/21/2023] [Revised: 11/15/2023] [Accepted: 12/08/2023] [Indexed: 12/19/2023]
Abstract
BACKGROUND OCTN1 belongs to the SLC22 family, which includes transporters for cationic, zwitterionic, and anionic substrates. OCTN1 function and role in cells are still poorly understood. Not only cations, such as TEA, but also zwitterions, such as carnitine and ergothioneine, figure among transported molecules. METHODS In this work, we carried out transport assays measuring [14C]-TEA and [3H]-Carnitine in proteoliposomes reconstituted with the recombinant human OCTN1 in the presence of Na+ or other cations. The homology model of OCTN1 was built using the structure of OCT3 as a template for docking analysis. RESULTS TEA and carnitine did not inhibit each other. Moreover, carnitine uptake was not affected by the presence of Na+ and TEBA, whereas TEA was strongly inhibited by both compounds. Computational data revealed that TEA, Na+, and carnitine can interact with E381 in the OCTN1 substrate site. Differently from TEA, in the presence of Na+, carnitine is still able to interact with the binding site via R469. CONCLUSIONS The lack of mutual inhibition of the two prototype substrates, the different effect of Na+ and TEBA on their transport reaction, together with the computational analysis supports the existence of two transport pathways for cations and zwitterions. GENERAL SIGNIFICANCE The results shed new light on the transport mechanisms of OCTN1, helping to get further insights into the structure/function relationships. The described results correlate well with previous and very recent findings on the polyspecificity of the OCT group of transporters belonging to the same family.
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Affiliation(s)
- Lorena Pochini
- Department DiBEST (Biologia, Ecologia, Scienze della Terra) Laboratory of Biochemistry, Molecular Biotechnology, and Molecular Biology, University of Calabria, Via Bucci 4C, 6C, 87036 Arcavacata di Rende, Italy; National Research Council (CNR), Institute of Biomembranes, Bioenergetics and Molecular Biotechnologies (IBIOM), via Amendola 122/O, 70126 Bari, Italy
| | - Francesca Barone
- Department DiBEST (Biologia, Ecologia, Scienze della Terra) Laboratory of Biochemistry, Molecular Biotechnology, and Molecular Biology, University of Calabria, Via Bucci 4C, 6C, 87036 Arcavacata di Rende, Italy
| | - Lara Console
- Department DiBEST (Biologia, Ecologia, Scienze della Terra) Laboratory of Biochemistry, Molecular Biotechnology, and Molecular Biology, University of Calabria, Via Bucci 4C, 6C, 87036 Arcavacata di Rende, Italy
| | - Chiara Brunocilla
- Department DiBEST (Biologia, Ecologia, Scienze della Terra) Laboratory of Biochemistry, Molecular Biotechnology, and Molecular Biology, University of Calabria, Via Bucci 4C, 6C, 87036 Arcavacata di Rende, Italy
| | - Michele Galluccio
- Department DiBEST (Biologia, Ecologia, Scienze della Terra) Laboratory of Biochemistry, Molecular Biotechnology, and Molecular Biology, University of Calabria, Via Bucci 4C, 6C, 87036 Arcavacata di Rende, Italy
| | - Mariafrancesca Scalise
- Department DiBEST (Biologia, Ecologia, Scienze della Terra) Laboratory of Biochemistry, Molecular Biotechnology, and Molecular Biology, University of Calabria, Via Bucci 4C, 6C, 87036 Arcavacata di Rende, Italy.
| | - Cesare Indiveri
- Department DiBEST (Biologia, Ecologia, Scienze della Terra) Laboratory of Biochemistry, Molecular Biotechnology, and Molecular Biology, University of Calabria, Via Bucci 4C, 6C, 87036 Arcavacata di Rende, Italy; National Research Council (CNR), Institute of Biomembranes, Bioenergetics and Molecular Biotechnologies (IBIOM), via Amendola 122/O, 70126 Bari, Italy.
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16
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Drobnik M, Smólski J, Grądalski Ł, Niemirka S, Młynarska E, Rysz J, Franczyk B. Mechanosensitive Cation Channel Piezo1 Is Involved in Renal Fibrosis Induction. Int J Mol Sci 2024; 25:1718. [PMID: 38338996 PMCID: PMC10855652 DOI: 10.3390/ijms25031718] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2023] [Revised: 01/27/2024] [Accepted: 01/29/2024] [Indexed: 02/12/2024] Open
Abstract
Renal fibrosis, the result of different pathological processes, impairs kidney function and architecture, and usually leads to renal failure development. Piezo1 is a mechanosensitive cation channel highly expressed in kidneys. Activation of Piezo1 by mechanical stimuli increases cations influx into the cell with slight preference of calcium ions. Two different models of Piezo1 activation are considered: force through lipid and force through filament. Expression of Piezo1 on mRNA and protein levels was confirmed within the kidney. Their capacity is increased in the fibrotic kidney. The pharmacological tools for Piezo1 research comprise selective activators of the channels (Yoda1 and Jedi1/2) as well as non-selective inhibitors (spider peptide toxin) GsMTx4. Piezo1 is hypothesized to be the upstream element responsible for the activation of integrin. This pathway (calcium/calpain2/integrin beta1) is suggested to participate in profibrotic response induced by mechanical stimuli. Administration of the Piezo1 unspecific inhibitor or activators to unilateral ureter obstruction (UUO) mice or animals with folic acid-induced fibrosis modulates extracellular matrix deposition and influences kidney function. All in all, according to the recent data Piezo1 plays an important role in kidney fibrosis development. This channel has been selected as the target for pharmacotherapy of renal fibrosis.
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Affiliation(s)
- Marta Drobnik
- Department of Nephrocardiology, Medical University of Lodz, ul. Żeromskiego 113, 90-549 Lodz, Poland; (M.D.)
| | - Jakub Smólski
- Department of Nephrocardiology, Medical University of Lodz, ul. Żeromskiego 113, 90-549 Lodz, Poland; (M.D.)
| | - Łukasz Grądalski
- Department of Nephrocardiology, Medical University of Lodz, ul. Żeromskiego 113, 90-549 Lodz, Poland; (M.D.)
| | - Szymon Niemirka
- Department of Nephrocardiology, Medical University of Lodz, ul. Żeromskiego 113, 90-549 Lodz, Poland; (M.D.)
| | - Ewelina Młynarska
- Department of Nephrocardiology, Medical University of Lodz, ul. Żeromskiego 113, 90-549 Lodz, Poland; (M.D.)
| | - Jacek Rysz
- Department of Nephrology, Hypertension and Family Medicine, Medical University of Lodz, ul. Żeromskiego 113, 90-549 Lodz, Poland
| | - Beata Franczyk
- Department of Nephrocardiology, Medical University of Lodz, ul. Żeromskiego 113, 90-549 Lodz, Poland; (M.D.)
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17
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Zhou Y, Bennett TM, Ruzycki PA, Guo Z, Cao YQ, Shahidullah M, Delamere NA, Shiels A. A Cataract-Causing Mutation in the TRPM3 Cation Channel Disrupts Calcium Dynamics in the Lens. Cells 2024; 13:257. [PMID: 38334649 PMCID: PMC10854584 DOI: 10.3390/cells13030257] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2024] [Revised: 01/23/2024] [Accepted: 01/26/2024] [Indexed: 02/10/2024] Open
Abstract
TRPM3 belongs to the melastatin sub-family of transient receptor potential (TRPM) cation channels and has been shown to function as a steroid-activated, heat-sensitive calcium ion (Ca2+) channel. A missense substitution (p.I65M) in the TRPM3 gene of humans (TRPM3) and mice (Trpm3) has been shown to underlie an inherited form of early-onset, progressive cataract. Here, we model the pathogenetic effects of this cataract-causing mutation using 'knock-in' mutant mice and human cell lines. Trpm3 and its intron-hosted micro-RNA gene (Mir204) were strongly co-expressed in the lens epithelium and other non-pigmented and pigmented ocular epithelia. Homozygous Trpm3-mutant lenses displayed elevated cytosolic Ca2+ levels and an imbalance of sodium (Na+) and potassium (K+) ions coupled with increased water content. Homozygous TRPM3-mutant human lens epithelial (HLE-B3) cell lines and Trpm3-mutant lenses exhibited increased levels of phosphorylated mitogen-activated protein kinase 1/extracellular signal-regulated kinase 2 (MAPK1/ERK2/p42) and MAPK3/ERK1/p44. Mutant TRPM3-M65 channels displayed an increased sensitivity to external Ca2+ concentration and an altered dose response to pregnenolone sulfate (PS) activation. Trpm3-mutant lenses shared the downregulation of genes involved in insulin/peptide secretion and the upregulation of genes involved in Ca2+ dynamics. By contrast, Trpm3-deficient lenses did not replicate the pathophysiological changes observed in Trpm3-mutant lenses. Collectively, our data suggest that a cataract-causing substitution in the TRPM3 cation channel elicits a deleterious gain-of-function rather than a loss-of-function mechanism in the lens.
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Affiliation(s)
- Yuefang Zhou
- Department of Ophthalmology and Visual Sciences, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Thomas M. Bennett
- Department of Ophthalmology and Visual Sciences, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Philip A. Ruzycki
- Department of Ophthalmology and Visual Sciences, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Zhaohua Guo
- Department of Anesthesiology and Washington University Pain Center, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Yu-Qing Cao
- Department of Anesthesiology and Washington University Pain Center, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Mohammad Shahidullah
- Department of Physiology, University of Arizona College of Medicine, Tucson, AZ 85724, USA
| | - Nicholas A. Delamere
- Department of Physiology, University of Arizona College of Medicine, Tucson, AZ 85724, USA
| | - Alan Shiels
- Department of Ophthalmology and Visual Sciences, Washington University School of Medicine, St. Louis, MO 63110, USA
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18
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Takahashi H, Asakura M, Ide T, Hayakawa T. Mutational analysis of the transmembrane α4-helix of Bacillus thuringiensis mosquito-larvicidal Cry4Aa toxin. Curr Microbiol 2024; 81:80. [PMID: 38281302 PMCID: PMC10822788 DOI: 10.1007/s00284-023-03602-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2023] [Accepted: 12/26/2023] [Indexed: 01/30/2024]
Abstract
Cry4Aa, produced by Bacillus thuringiensis subsp. israelensis, exhibits specific toxicity to larvae of medically important mosquito genera. Cry4Aa functions as a pore-forming toxin, and a helical hairpin (α4-loop-α5) of domain I is believed to be the transmembrane domain that forms toxin pores. Pore formation is considered to be a central mode of Cry4Aa action, but the relationship between pore formation and toxicity is poorly understood. In the present study, we constructed Cry4Aa mutants in which each polar amino acid residues within the transmembrane α4 helix was replaced with glutamic acid. Bioassays using Culex pipiens mosquito larvae and subsequent ion permeability measurements using symmetric KCl solution revealed an apparent correlation between toxicity and toxin pore conductance for most of the Cry4Aa mutants. In contrast, the Cry4Aa mutant H178E was a clear exception, almost losing its toxicity but still exhibiting a moderately high conductivity of about 60% of the wild-type. Furthermore, the conductance of the pore formed by the N190E mutant (about 50% of the wild-type) was close to that of H178E, but the toxicity was significantly higher than that of H178E. Ion selectivity measurements using asymmetric KCl solution revealed a significant decrease in cation selectivity of toxin pores formed by H178E compared to N190E. Our data suggest that the toxicity of Cry4Aa is primarily pore related. The formation of toxin pores that are highly ion-permeable and also highly cation-selective may enhance the influx of cations and water into the target cell, thereby facilitating the eventual death of mosquito larvae.
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Affiliation(s)
- Hirokazu Takahashi
- Graduate School of Interdisciplinary Science and Engineering in Health Systems, Okayama University, 3-1-1 Tsushima-Naka, Kita-Ku, Okayama, 700-8530, Japan
| | - Mami Asakura
- Graduate School of Interdisciplinary Science and Engineering in Health Systems, Okayama University, 3-1-1 Tsushima-Naka, Kita-Ku, Okayama, 700-8530, Japan
| | - Toru Ide
- Graduate School of Interdisciplinary Science and Engineering in Health Systems, Okayama University, 3-1-1 Tsushima-Naka, Kita-Ku, Okayama, 700-8530, Japan
| | - Tohru Hayakawa
- Graduate School of Interdisciplinary Science and Engineering in Health Systems, Okayama University, 3-1-1 Tsushima-Naka, Kita-Ku, Okayama, 700-8530, Japan.
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19
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Ruiz Munevar M, Rizzi V, Portioli C, Vidossich P, Cao E, Parrinello M, Cancedda L, De Vivo M. Cation Chloride Cotransporter NKCC1 Operates through a Rocking-Bundle Mechanism. J Am Chem Soc 2024; 146:552-566. [PMID: 38146212 PMCID: PMC10786066 DOI: 10.1021/jacs.3c10258] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2023] [Revised: 12/05/2023] [Accepted: 12/06/2023] [Indexed: 12/27/2023]
Abstract
The sodium, potassium, and chloride cotransporter 1 (NKCC1) plays a key role in tightly regulating ion shuttling across cell membranes. Lately, its aberrant expression and function have been linked to numerous neurological disorders and cancers, making it a novel and highly promising pharmacological target for therapeutic interventions. A better understanding of how NKCC1 dynamically operates would therefore have broad implications for ongoing efforts toward its exploitation as a therapeutic target through its modulation. Based on recent structural data on NKCC1, we reveal conformational motions that are key to its function. Using extensive deep-learning-guided atomistic simulations of NKCC1 models embedded into the membrane, we captured complex dynamical transitions between alternate open conformations of the inner and outer vestibules of the cotransporter and demonstrated that NKCC1 has water-permeable states. We found that these previously undefined conformational transitions occur via a rocking-bundle mechanism characterized by the cooperative angular motion of transmembrane helices (TM) 4 and 9, with the contribution of the extracellular tip of TM 10. We found these motions to be critical in modulating ion transportation and in regulating NKCC1's water transporting capabilities. Specifically, we identified interhelical dynamical contacts between TM 10 and TM 6, which we functionally validated through mutagenesis experiments of 4 new targeted NKCC1 mutants. We conclude showing that those 4 residues are highly conserved in most Na+-dependent cation chloride cotransporters (CCCs), which highlights their critical mechanistic implications, opening the way to new strategies for NKCC1's function modulation and thus to potential drug action on selected CCCs.
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Affiliation(s)
- Manuel
José Ruiz Munevar
- Laboratory
of Molecular Modelling & Drug Discovery, Istituto Italiano di Tecnologia, Via Morego 30, Genoa 16163, Italy
| | - Valerio Rizzi
- Biomolecular
& Pharmaceutical Modelling Group, Université
de Genève, Rue Michel-Servet 1, Geneva CH-1211 4, Switzerland
| | - Corinne Portioli
- Laboratory
of Nanotechnology for Precision Medicine, Istituto Italiano di Tecnologia, Via Morego 30, Genoa 16163, Italy
- Laboratory
of Brain Development and Disease, Istituto
Italiano di Tecnologia, Via Morego 30, Genoa 16163, Italy
| | - Pietro Vidossich
- Laboratory
of Molecular Modelling & Drug Discovery, Istituto Italiano di Tecnologia, Via Morego 30, Genoa 16163, Italy
| | - Erhu Cao
- Department
of Biochemistry, University of Utah School
of Medicine, Salt Lake City, Utah 84112-5650, United States
| | - Michele Parrinello
- Laboratory
of Atomistic Simulations, Istituto Italiano
di Tecnologia, Via Morego 30, Genoa 16163, Italy
| | - Laura Cancedda
- Laboratory
of Brain Development and Disease, Istituto
Italiano di Tecnologia, Via Morego 30, Genoa 16163, Italy
| | - Marco De Vivo
- Laboratory
of Molecular Modelling & Drug Discovery, Istituto Italiano di Tecnologia, Via Morego 30, Genoa 16163, Italy
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20
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Ailabouni AS, Mettu VS, Thakur A, Singh DK, Prasad B. Effect of Cimetidine on Metformin Pharmacokinetics and Endogenous Metabolite Levels in Rats. Drug Metab Dispos 2024; 52:86-94. [PMID: 38049999 PMCID: PMC10801632 DOI: 10.1124/dmd.123.001470] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2023] [Revised: 11/03/2023] [Accepted: 11/27/2023] [Indexed: 12/06/2023] Open
Abstract
Tubular secretion is a primary mechanism along with glomerular filtration for renal elimination of drugs and toxicants into urine. Organic cation transporters (OCTs) and multidrug and toxic extrusion (MATE) transporters facilitate the active secretion of cationic substrates, including drugs such as metformin and endogenous cations. We hypothesized that administration of cimetidine, an Oct/Mate inhibitor, will result in increased plasma levels and decreased renal clearance of metformin and endogenous Oct/Mate substrates in rats. A paired rat pharmacokinetic study was carried out in which metformin (5 mg/kg, intravenous) was administered as an exogenous substrate of Oct/Mate transporters to six Sprague-Dawley rats with and without cimetidine (100 mg/kg, intraperitoneal). When co-administered with cimetidine, metformin area under the curve increased significantly by 3.2-fold, and its renal clearance reduced significantly by 73%. Untargeted metabolomics was performed to investigate the effect of cimetidine on endogenous metabolome in the blood and urine samples. Over 8,000 features (metabolites) were detected in the blood, which were shortlisted using optimized criteria, i.e., a significant increase (P value < 0.05) in metabolite peak intensity in the cimetidine-treated group, reproducible retention time, and quality of chromatogram peak. The metabolite hits were classified into three groups that can potentially distinguish inhibition of i) extra-renal uptake transport or catabolism, ii) renal Octs, and iii) renal efflux transporters or metabolite formation. The metabolomics approach identified novel putative endogenous substrates of cationic transporters that could be tested as potential biomarkers to predict Oct/Mate transporter mediated drug-drug interactions in the preclinical stages. SIGNIFICANCE STATEMENT: Endogenous substrates of renal transporters in animal models could be used as potential biomarkers to predict renal drug-drug interactions in early drug development. Here we demonstrated that cimetidine, an inhibitor of organic cation transporters (Oct/Mate), could alter the pharmacokinetics of metformin and endogenous cationic substrates in rats. Several putative endogenous metabolites of Oct/Mate transporters were identified using metabolomics approach, which could be tested as potential transporter biomarkers to predict renal drug-drug interaction of Oct/Mate substrates.
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Affiliation(s)
| | - Vijaya Saradhi Mettu
- Department of Pharmaceutical Sciences, Washington State University, Spokane, Washington
| | - Aarzoo Thakur
- Department of Pharmaceutical Sciences, Washington State University, Spokane, Washington
| | - Dilip Kumar Singh
- Department of Pharmaceutical Sciences, Washington State University, Spokane, Washington
| | - Bhagwat Prasad
- Department of Pharmaceutical Sciences, Washington State University, Spokane, Washington
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21
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Weaver AC, Braun TC, Braun JA, Golder HM, Block E, Lean IJ. Effects of negative dietary cation-anion difference and calcidiol supplementation in transition diets fed to sows on piglet survival, piglet weight, and sow metabolism. J Anim Sci 2024; 102:skae027. [PMID: 38285624 PMCID: PMC10889728 DOI: 10.1093/jas/skae027] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2023] [Accepted: 01/27/2024] [Indexed: 01/31/2024] Open
Abstract
Diets that provide a negative dietary anion cation difference (DCAD) and supplement with a vitamin D metabolite 25-OH-D3 (calcidiol) may increase calcium availability at parturition, and enhance piglet survival and performance. This factorial study assessed the effects of DCAD, calcidiol (50 µg/kg), and parity (parity 1 or >1) and their interactions. Large White and Landrace sows (n = 328), parity 1 to 8 were randomly allocated in blocks to treatment diets from day 103 of gestation until day 3 postfarrow: 1) negative DCAD without calcidiol (negative DCAD + no CA), n = 84, 2) negative DCAD with calcidiol (negative DCAD + CA) n = 84, 3) positive DCAD without calcidiol (negative DCAD + no CA), n = 81, and 4) positive DCAD with calcidiol (positive DCAD + CA), n = 79. Negative DCAD diets were acidified with an anionic feed (2 kg/t) and magnesium sulfate (2 kg/t). All treatment diets contained cholecalciferol at 1,000 IU/kg. Dry sow diets contained 14.8% crude protein (CP), 5.4% crude fiber (CF), 0.8% Ca, and 83 mEq/kg DCAD. Treatment diets 1 and 2 contained 17.5% CP, 7.3% CF, 0.8% Ca, and -2 mEq/kg DCAD. Treatment diets 3 and 4 contained 17.4% CP, 7.4% CF, 0.8% Ca, and 68 mEq/kg DCAD. Before farrowing, all negative DCAD sows had lower urine pH than all sows fed a positive DCAD (5.66 ± 0.05 and 6.29 ± 0.05, respectively; P < 0.01); urinary pH was acidified for both DCAD treatments indicating metabolic acidification. The percentage of sows with stillborn piglets was not affected by DCAD, calcidiol, or parity alone but sows fed the negative DCAD + CA diet had a 28% reduction in odds of stillbirth compared to the negative DCAD + no CA diet and even lesser odds to the positive DCAD + CA diet. At day 1 after farrowing, blood gas, and mineral and metabolite concentrations were consistent with feeding a negative DCAD diet and that negative DCAD diets influence energy metabolism, as indicated by increased glucose, cholesterol, and osteocalcin concentrations and reduced nonesterified free fatty acids and 3-hydroxybutyrate concentrations. In the subsequent litter, total piglets born and born alive (14.7 ± 0.3 and 13.8 ± 0.3 piglets, respectively; P = 0.029) was greater for positive DCAD diets compared to negative DCAD diets; and there was an interaction between DCAD, calcidiol, and parity (P = 0.002). Feeding a negative DCAD diet influenced stillbirth, subsequent litter size, and metabolic responses at farrowing. More studies are needed to define optimal diets prefarrowing for sows.
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Affiliation(s)
| | | | | | | | - Elliot Block
- Arm & Hammer Animal Nutrition, Princeton, NJ 08543, USA
| | - Ian John Lean
- South Australian Research and Development Institute, Rosedale, SA 5350, Australia
- Scibus, Camden, NSW 2570, Australia
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22
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Gamba G. From Fish Physiology to Human Disease: The Discovery of the NCC, NKCC2, and the Cation-Coupled Chloride Cotransporters. Kidney360 2024; 5:133-141. [PMID: 37968800 PMCID: PMC10833596 DOI: 10.34067/kid.0000000000000307] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/28/2023] [Accepted: 10/26/2023] [Indexed: 11/17/2023]
Abstract
The renal Na-K-2Cl and Na-Cl cotransporters are the major salt reabsorption pathways in the thick ascending limb of Henle loop and the distal convoluted tubule, respectively. These transporters are the target of the loop and thiazide type diuretics extensively used in the world for the treatment of edematous states and arterial hypertension. The diuretics appeared in the market many years before the salt transport systems were discovered. The evolving of the knowledge and the cloning of the genes encoding the Na-K-2Cl and Na-Cl cotransporters were possible thanks to the study of marine species. This work presents the history of how we came to know the mechanisms for the loop and thiazide type diuretics actions, the use of marine species in the cloning process of these cotransporters and therefore in the whole solute carrier cotransproters 12 (SLC12) family of electroneutral cation chloride cotransporters, and the disease associated with each member of the family.
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Affiliation(s)
- Gerardo Gamba
- Molecular Physiology Unit, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México and Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, Tlalpan, Mexico City, Mexico
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23
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Honan LE, Fraser-Spears R, Daws LC. Organic cation transporters in psychiatric and substance use disorders. Pharmacol Ther 2024; 253:108574. [PMID: 38072333 PMCID: PMC11052553 DOI: 10.1016/j.pharmthera.2023.108574] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2023] [Revised: 11/01/2023] [Accepted: 11/30/2023] [Indexed: 12/23/2023]
Abstract
Psychiatric and substance use disorders inflict major public health burdens worldwide. Their widespread burden is compounded by a dearth of effective treatments, underscoring a dire need to uncover novel therapeutic targets. In this review, we summarize the literature implicating organic cation transporters (OCTs), including three subtypes of OCTs (OCT1, OCT2, and OCT3) and the plasma membrane monoamine transporter (PMAT), in the neurobiology of psychiatric and substance use disorders with an emphasis on mood and anxiety disorders, alcohol use disorder, and psychostimulant use disorder. OCTs transport monoamines with a low affinity but high capacity, situating them to play a central role in regulating monoamine homeostasis. Preclinical evidence discussed here suggests that OCTs may serve as promising targets for treatment of psychiatric and substance use disorders and encourage future research into their therapeutic potential.
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Affiliation(s)
- Lauren E Honan
- The University of Texas Health Science Center at San Antonio, Department of Cellular & Integrative Physiology, USA
| | - Rheaclare Fraser-Spears
- University of the Incarnate Word, Feik School of Pharmacy, Department of Pharmaceutical Sciences, USA
| | - Lynette C Daws
- The University of Texas Health Science Center at San Antonio, Department of Cellular & Integrative Physiology, USA; The University of Texas Health Science Center at San Antonio, Department of Pharmacology, USA.
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24
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Delpire E, Terker AS, Gagnon KB. Pharmacology of Compounds Targeting Cation-Chloride Cotransporter Physiology. Handb Exp Pharmacol 2024; 283:249-284. [PMID: 37563251 PMCID: PMC10823342 DOI: 10.1007/164_2023_692] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/12/2023]
Abstract
Transporters of the solute carrier family 12 (SLC12) carry inorganic cations such as Na+ and/or K+ alongside Cl across the plasma membrane of cells. These tightly coupled, electroneutral, transporters are expressed in almost all tissues/organs in the body where they fulfil many critical functions. The family includes two key transporters participating in salt reabsorption in the kidney: the Na-K-2Cl cotransporter-2 (NKCC2), expressed in the loop of Henle, and the Na-Cl cotransporter (NCC), expressed in the distal convoluted tubule. NCC and NKCC2 are the targets of thiazides and "loop" diuretics, respectively, drugs that are widely used in clinical medicine to treat hypertension and edema. Bumetanide, in addition to its effect as a loop diuretic, has recently received increasing attention as a possible therapeutic agent for neurodevelopmental disorders. This chapter also describes how over the past two decades, the pharmacology of Na+ independent transporters has expanded significantly to provide novel tools for research. This work has indeed led to the identification of compounds that are 100-fold to 1000-fold more potent than furosemide, the first described inhibitor of K-Cl cotransport, and identified compounds that possibly directly stimulate the function of the K-Cl cotransporter. Finally, the recent cryo-electron microscopy revolution has begun providing answers as to where and how pharmacological agents bind to and affect the function of the transporters.
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Affiliation(s)
- Eric Delpire
- Department of Anesthesiology, Vanderbilt University School of Medicine, Nashville, TN, USA.
| | - Andrew S Terker
- Department of Medicine, Vanderbilt University School of Medicine, Nashville, TN, USA
| | - Kenneth B Gagnon
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX, USA
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25
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Bakshi A, Choi WG, Kim SH, Gilroy S. The vacuolar Ca 2+ transporter CATION EXCHANGER 2 regulates cytosolic calcium homeostasis, hypoxic signaling, and response to flooding in Arabidopsis thaliana. New Phytol 2023; 240:1830-1847. [PMID: 37743731 DOI: 10.1111/nph.19274] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/16/2023] [Accepted: 08/23/2023] [Indexed: 09/26/2023]
Abstract
Flooding represents a major threat to global agricultural productivity and food security, but plants are capable of deploying a suite of adaptive responses that can lead to short- or longer-term survival to this stress. One cellular pathway thought to help coordinate these responses is via flooding-triggered Ca2+ signaling. We have mined publicly available transcriptomic data from Arabidopsis subjected to flooding or low oxygen stress to identify rapidly upregulated, Ca2+ -related transcripts. We then focused on transporters likely to modulate Ca2+ signals. Candidates emerging from this analysis included AUTOINHIBITED Ca2+ ATPASE 1 and CATION EXCHANGER 2. We therefore assayed mutants in these genes for flooding sensitivity at levels from growth to patterns of gene expression and the kinetics of flooding-related Ca2+ changes. Knockout mutants in CAX2 especially showed enhanced survival to soil waterlogging coupled with suppressed induction of many marker genes for hypoxic response and constitutive activation of others. CAX2 mutants also generated larger and more sustained Ca2+ signals in response to both flooding and hypoxic challenges. CAX2 is a Ca2+ transporter located on the tonoplast, and so these results are consistent with an important role for vacuolar Ca2+ transport in the signaling systems that trigger flooding response.
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Affiliation(s)
- Arkadipta Bakshi
- Department of Botany, University of Wisconsin, Birge Hall, 430 Lincoln Dr., Madison, WI, 53706, USA
| | - Won-Gyu Choi
- Department of Biochemistry and Molecular Biology, 1664 N. Virginia St, Reno, NV, 89557, USA
| | - Su-Hwa Kim
- Department of Biochemistry and Molecular Biology, 1664 N. Virginia St, Reno, NV, 89557, USA
| | - Simon Gilroy
- Department of Botany, University of Wisconsin, Birge Hall, 430 Lincoln Dr., Madison, WI, 53706, USA
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26
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Chhetri KB, Jang YH, Lansac Y, Maiti PK. DNA groove preference shift upon phosphorylation of a protamine-like cationic peptide. Phys Chem Chem Phys 2023; 25:31335-31345. [PMID: 37960891 DOI: 10.1039/d3cp03803c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2023]
Abstract
Protamines, arginine-rich DNA-binding proteins, are responsible for chromatin compaction in sperm cells, but their DNA groove preference, major or minor, is not clearly identified. We herein study the DNA groove preference of a short protamine-like cationic peptide before and after phosphorylation, using all-atom molecular dynamics and umbrella sampling simulations. According to various thermodynamic and structural analyses, a peptide in its non-phosphorylated native state prefers the minor groove over the major groove, but phosphorylation of the peptide bound to the minor groove not only reduces its binding affinity but also brings a serious deformation of the minor groove, eliminating the minor-groove preference. As protamines are heavily phosphorylated before binding to DNA, we expect that the structurally disordered phosphorylated protamines would prefer major grooves to enter into DNA during spermatogenesis.
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Affiliation(s)
- Khadka B Chhetri
- Center for Condensed Matter Theory, Department of Physics, Indian Institute of Science, Bangalore 560012, India.
- Department of Physics, Prithvinarayan Campus, Tribhuvan University, Pokhara, Nepal
| | - Yun Hee Jang
- Department of Energy Science and Engineering, DGIST, Daegu 42988, Korea
- GREMAN, CNRS UMR 7347, Université de Tours, 37200 Tours, France
- Laboratoire de Physique des Solides, CNRS UMR 8502, Université Paris Saclay, 91405 Orsay, France
| | - Yves Lansac
- GREMAN, CNRS UMR 7347, Université de Tours, 37200 Tours, France
- Laboratoire de Physique des Solides, CNRS UMR 8502, Université Paris Saclay, 91405 Orsay, France
| | - Prabal K Maiti
- Center for Condensed Matter Theory, Department of Physics, Indian Institute of Science, Bangalore 560012, India.
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27
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Lim L, Kang J, Song J. Extreme diversity of 12 cations in folding ALS-linked hSOD1 unveils novel hSOD1-dependent mechanisms for Fe 2+/Cu 2+-induced cytotoxicity. Sci Rep 2023; 13:19868. [PMID: 37964005 PMCID: PMC10645853 DOI: 10.1038/s41598-023-47338-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2023] [Accepted: 11/12/2023] [Indexed: 11/16/2023] Open
Abstract
153-Residue copper-zinc superoxide dismutase 1 (hSOD1) is the first gene whose mutation was linked to FALS. To date, > 180 ALS-causing mutations have been identified within hSOD1, yet the underlying mechanism still remains mysterious. Mature hSOD1 is exceptionally stable constrained by a disulfide bridge to adopt a Greek-key β-barrel fold that accommodates copper/zinc cofactors. Conversely, nascent hSOD1 is unfolded and susceptible to aggregation and amyloid formation, requiring Zn2+ to initiate folding to a coexistence of folded and unfolded states. Recent studies demonstrate mutations that disrupt Zn2+-binding correlate with their ability to form toxic aggregates. Therefore, to decode the role of cations in hSOD1 folding provides not only mechanistic insights, but may bear therapeutic implications for hSOD1-linked ALS. Here by NMR, we visualized the effect of 12 cations: 8 essential for humans (Na+, K+, Ca2+, Zn2+, Mg2+, Mn2+, Cu2+, Fe2+), 3 mimicking zinc (Ni2+, Cd2+, Co2+), and environmentally abundant Al3+. Surprisingly, most cations, including Zn2+-mimics, showed negligible binding or induction for folding of nascent hSOD1. Cu2+ exhibited extensive binding to the unfolded state but led to severe aggregation. Unexpectedly, for the first time Fe2+ was deciphered to have Zn2+-like folding-inducing capacity. Zn2+ was unable to induce folding of H80S/D83S-hSOD1, while Fe2+ could. In contrast, Zn2+ could trigger folding of G93A-hSOD1, but Fe2+ failed. Notably, pre-existing Fe2+ disrupted the Zn2+-induced folding of G93A-hSOD1. Comparing with the ATP-induced folded state, our findings delineate that hSOD1 maturation requires: (1) intrinsic folding capacity encoded by the sequence; (2) specific Zn2+-coordination; (3) disulfide formation and Cu-load catalyzed by hCCS. This study unveils a previously-unknown interplay of cations in governing the initial folding of hSOD1, emphasizing the pivotal role of Zn2+ in hSOD1-related ALS and implying new hSOD1-dependent mechanisms for Cu2+/Fe2+-induced cytotoxicity, likely relevant to aging and other diseases.
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Affiliation(s)
- Liangzhong Lim
- Department of Biological Sciences, Faculty of Science, National University of Singapore, Singapore, 119260, Republic of Singapore
| | - Jian Kang
- Department of Biological Sciences, Faculty of Science, National University of Singapore, Singapore, 119260, Republic of Singapore
| | - Jianxing Song
- Department of Biological Sciences, Faculty of Science, National University of Singapore, Singapore, 119260, Republic of Singapore.
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28
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Stewart GW, Gibson JS, Rees DC. The cation-leaky hereditary stomatocytosis syndromes: A tale of six proteins. Br J Haematol 2023; 203:509-522. [PMID: 37679660 DOI: 10.1111/bjh.19093] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2023] [Revised: 08/13/2023] [Accepted: 08/22/2023] [Indexed: 09/09/2023]
Abstract
This review concerns a series of dominantly inherited haemolytic anaemias in which the membrane of the erythrocyte 'leaks' the univalent cations, compromising the osmotic stability of the cell. The majority of the conditions are explained by mutations in one of six genes, coding for multispanning membrane proteins of different structure and function. These are: RhAG, coding for an ammonium carrier; SLC4A1, coding for the band 3 anion exchanger; PIEZO1, coding for a mechanosensitive cation channel; GLUT1, coding for a glucose transporter; KCNN4, coding for an internal-calcium-activated potassium channel; and ABCB6, coding for a porphyrin transporter. This review describes the five clinical syndromes associated with genetic defects in these genes and their variable genotype/phenotype relationships.
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Affiliation(s)
- Gordon W Stewart
- Division of Medicine, Faculty of Medical Sciences, University College London, London, UK
| | - John S Gibson
- Department of Veterinary Medicine, University of Cambridge, Cambridge, UK
| | - David C Rees
- Haematological Medicine, Kings College London, London, UK
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29
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Kamkin AG, Kamkina OV, Kazansky VE, Mitrokhin VM, Bilichenko A, Nasedkina EA, Shileiko SA, Rodina AS, Zolotareva AD, Zolotarev VI, Sutyagin PV, Mladenov MI. Identification of RNA reads encoding different channels in isolated rat ventricular myocytes and the effect of cell stretching on L-type Ca 2+current. Biol Direct 2023; 18:70. [PMID: 37899484 PMCID: PMC10614344 DOI: 10.1186/s13062-023-00427-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2023] [Accepted: 10/13/2023] [Indexed: 10/31/2023] Open
Abstract
BACKGROUND The study aimed to identify transcripts of specific ion channels in rat ventricular cardiomyocytes and determine their potential role in the regulation of ionic currents in response to mechanical stimulation. The gene expression levels of various ion channels in freshly isolated rat ventricular cardiomyocytes were investigated using the RNA-seq technique. We also measured changes in current through CaV1.2 channels under cell stretching using the whole-cell patch-clamp method. RESULTS Among channels that showed mechanosensitivity, significant amounts of TRPM7, TRPC1, and TRPM4 transcripts were found. We suppose that the recorded L-type Ca2+ current is probably expressed through CaV1.2. Furthermore, stretching cells by 6, 8, and 10 μm, which increases ISAC through the TRPM7, TRPC1, and TRPM4 channels, also decreased ICa,L through the CaV1.2 channels in K+ in/K+ out, Cs+ in/K+ out, K+ in/Cs+ out, and Cs+ in/Cs+ out solutions. The application of a nonspecific ISAC blocker, Gd3+, during cell stretching eliminated ISAC through nonselective cation channels and ICa,L through CaV1.2 channels. Since the response to Gd3+ was maintained in Cs+ in/Cs+ out solutions, we suggest that voltage-gated CaV1.2 channels in the ventricular myocytes of adult rats also exhibit mechanosensitive properties. CONCLUSIONS Our findings suggest that TRPM7, TRPC1, and TRPM4 channels represent stretch-activated nonselective cation channels in rat ventricular myocytes. Probably the CaV1.2 channels in these cells exhibit mechanosensitive properties. Our results provide insight into the molecular mechanisms underlying stretch-induced responses in rat ventricular myocytes, which may have implications for understanding cardiac physiology and pathophysiology.
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Affiliation(s)
- Andre G Kamkin
- Department of Physiology, Pirogov Russian National Research Medical University, Moscow, Russian Federation
| | - Olga V Kamkina
- Department of Physiology, Pirogov Russian National Research Medical University, Moscow, Russian Federation
| | - Viktor E Kazansky
- Department of Physiology, Pirogov Russian National Research Medical University, Moscow, Russian Federation
| | - Vadim M Mitrokhin
- Department of Physiology, Pirogov Russian National Research Medical University, Moscow, Russian Federation
| | - Andrey Bilichenko
- Department of Physiology, Pirogov Russian National Research Medical University, Moscow, Russian Federation
| | - Elizaveta A Nasedkina
- Department of Physiology, Pirogov Russian National Research Medical University, Moscow, Russian Federation
| | - Stanislav A Shileiko
- Department of Physiology, Pirogov Russian National Research Medical University, Moscow, Russian Federation
| | - Anastasia S Rodina
- Department of Physiology, Pirogov Russian National Research Medical University, Moscow, Russian Federation
| | - Alexandra D Zolotareva
- Department of Physiology, Pirogov Russian National Research Medical University, Moscow, Russian Federation
| | - Valentin I Zolotarev
- Department of Physiology, Pirogov Russian National Research Medical University, Moscow, Russian Federation
| | - Pavel V Sutyagin
- Department of Physiology, Pirogov Russian National Research Medical University, Moscow, Russian Federation
| | - Mitko I Mladenov
- Department of Physiology, Pirogov Russian National Research Medical University, Moscow, Russian Federation.
- Faculty of Natural Sciences and Mathematics, Institute of Biology, "Ss. Cyril and Methodius" University, Skopje, North, Macedonia.
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Williams JT, Baker JJ, Zheng H, Dechow SJ, Fallon J, Murto M, Albrecht VJ, Gilliland HN, Olive AJ, Abramovitch RB. A genetic selection for Mycobacterium smegmatis mutants tolerant to killing by sodium citrate defines a combined role for cation homeostasis and osmotic stress in cell death. mSphere 2023; 8:e0035823. [PMID: 37681985 PMCID: PMC10597346 DOI: 10.1128/msphere.00358-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2023] [Accepted: 07/23/2023] [Indexed: 09/09/2023] Open
Abstract
Mycobacteria can colonize environments where the availability of metal ions is limited. Biological or inorganic chelators play an important role in limiting metal availability, and we developed a model to examine Mycobacterium smegmatis survival in the presence of the chelator sodium citrate. We observed that instead of restricting M. smegmatis growth, concentrated sodium citrate killed M. smegmatis. RNAseq analysis during sodium citrate treatment revealed transcriptional signatures of metal starvation and hyperosmotic stress. Notably, metal starvation and hyperosmotic stress, individually, do not kill M. smegmatis under these conditions. A forward genetic transposon selection was conducted to examine why sodium citrate was lethal, and several sodium-citrate-tolerant mutants were isolated. Based on the identity of three tolerant mutants, mgtE, treZ, and fadD6, we propose a dual stress model of killing by sodium citrate, where sodium citrate chelate metals from the cell envelope and then osmotic stress in combination with a weakened cell envelope causes cell lysis. This sodium citrate tolerance screen identified mutants in several other genes with no known function, with most conserved in the pathogen M. tuberculosis. Therefore, this model will serve as a basis to define their functions, potentially in maintaining cell wall integrity, cation homeostasis, or osmotolerance. IMPORTANCE Bacteria require mechanisms to adapt to environments with differing metal availability. When Mycobacterium smegmatis is treated with high concentrations of the metal chelator sodium citrate, the bacteria are killed. To define the mechanisms underlying killing by sodium citrate, we conducted a genetic selection and observed tolerance to killing in mutants of the mgtE magnesium transporter. Further characterization studies support a model where killing by sodium citrate is driven by a weakened cell wall and osmotic stress, that in combination cause cell lysis.
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Affiliation(s)
- John T. Williams
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, Michigan, USA
| | - Jacob J. Baker
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, Michigan, USA
| | - Huiqing Zheng
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, Michigan, USA
| | - Shelby J. Dechow
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, Michigan, USA
| | - Jared Fallon
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, Michigan, USA
| | - Megan Murto
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, Michigan, USA
| | - Veronica J. Albrecht
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, Michigan, USA
| | - Haleigh N. Gilliland
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, Michigan, USA
| | - Andrew J. Olive
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, Michigan, USA
| | - Robert B. Abramovitch
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, Michigan, USA
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REEDICH EJ, GENRY L, STEELE P, AVILA EMENA, DOWALIBY L, DROBYSHEVSKY A, MANUEL M, QUINLAN KA. Spinal motoneurons respond aberrantly to serotonin in a rabbit model of cerebral palsy. J Physiol 2023; 601:4271-4289. [PMID: 37584461 PMCID: PMC10543617 DOI: 10.1113/jp284803] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2023] [Accepted: 07/24/2023] [Indexed: 08/17/2023] Open
Abstract
Cerebral palsy (CP) is caused by a variety of factors that damage the developing central nervous system. Impaired motor control, including muscle stiffness and spasticity, is the hallmark of spastic CP. Rabbits that experience hypoxic-ischaemic (HI) injury in utero (at 70%-83% gestation) are born with muscle stiffness, hyperreflexia and, as recently discovered, increased 5-HT in the spinal cord. To determine whether serotonergic modulation of spinal motoneurons (MNs) contributes to motor deficits, we performed ex vivo whole cell patch clamp in neonatal rabbit spinal cord slices at postnatal day (P) 0-5. HI MNs responded to the application of α-methyl 5-HT (a 5-HT1 /5-HT2 receptor agonist) and citalopram (a selective 5-HT reuptake inhibitor) with increased amplitude and hyperpolarization of persistent inward currents and hyperpolarized threshold voltage for action potentials, whereas control MNs did not exhibit any of these responses. Although 5-HT similarly modulated MN properties of HI motor-unaffected and motor-affected kits, it affected sag/hyperpolarization-activated cation current (Ih ) and spike frequency adaptation only in HI motor-affected MNs. To further explore the differential sensitivity of MNs to 5-HT, we performed immunostaining for inhibitory 5-HT1A receptors in lumbar spinal MNs at P5. Fewer HI MNs expressed the 5-HT1A receptor compared to age-matched control MNs. This suggests that HI MNs may lack a normal mechanism of central fatigue, mediated by 5-HT1A receptors. Altered expression of other 5-HT receptors (including 5-HT2 ) likely also contributes to the robust increase in HI MN excitability. In summary, by directly exciting MNs, the increased concentration of spinal 5-HT in HI-affected rabbits can cause MN hyperexcitability, muscle stiffness and spasticity characteristic of CP. Therapeutic strategies that target serotonergic neuromodulation may be beneficial to individuals with CP. KEY POINTS: We used whole cell patch clamp electrophysiology to test the responsivity of spinal motoneurons (MNs) from neonatal control and hypoxia-ischaemia (HI) rabbits to 5-HT, which is elevated in the spinal cord after prenatal HI injury. HI rabbit MNs showed a more robust excitatory response to 5-HT than control rabbit MNs, including hyperpolarization of the persistent inward current and threshold voltage for action potentials. Although most MN properties of HI motor-unaffected and motor-affected kits responded similarly to 5-HT, 5-HT caused larger sag/hyperpolarization-activated cation current (Ih ) and altered repetitive firing patterns only in HI motor-affected MNs. Immunostaining revealed that fewer lumbar MNs expressed inhibitory 5-HT1A receptors in HI rabbits compared to controls, which could account for the more robust excitatory response of HI MNs to 5-HT. These results suggest that elevated 5-HT after prenatal HI injury could trigger a cascade of events that lead to muscle stiffness and altered motor unit development.
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Affiliation(s)
- E. J. REEDICH
- George and Anne Ryan Institute for Neuroscience, University of Rhode Island, Kingston, RI, USA
- Department of Biomedical and Pharmaceutical Sciences, College of Pharmacy, University of Rhode Island, Kingston, RI, USA
| | - L.T. GENRY
- George and Anne Ryan Institute for Neuroscience, University of Rhode Island, Kingston, RI, USA
- Department of Biomedical and Pharmaceutical Sciences, College of Pharmacy, University of Rhode Island, Kingston, RI, USA
- Interdisciplinary Neuroscience Program, University of Rhode Island, Kingston, RI, USA
| | - P.R. STEELE
- George and Anne Ryan Institute for Neuroscience, University of Rhode Island, Kingston, RI, USA
- Department of Biomedical and Pharmaceutical Sciences, College of Pharmacy, University of Rhode Island, Kingston, RI, USA
- Interdisciplinary Neuroscience Program, University of Rhode Island, Kingston, RI, USA
| | - E. MENA AVILA
- George and Anne Ryan Institute for Neuroscience, University of Rhode Island, Kingston, RI, USA
- Department of Biomedical and Pharmaceutical Sciences, College of Pharmacy, University of Rhode Island, Kingston, RI, USA
| | - L. DOWALIBY
- George and Anne Ryan Institute for Neuroscience, University of Rhode Island, Kingston, RI, USA
- Department of Biomedical and Pharmaceutical Sciences, College of Pharmacy, University of Rhode Island, Kingston, RI, USA
| | | | - M. MANUEL
- George and Anne Ryan Institute for Neuroscience, University of Rhode Island, Kingston, RI, USA
- Department of Biomedical and Pharmaceutical Sciences, College of Pharmacy, University of Rhode Island, Kingston, RI, USA
- Interdisciplinary Neuroscience Program, University of Rhode Island, Kingston, RI, USA
| | - K. A. QUINLAN
- George and Anne Ryan Institute for Neuroscience, University of Rhode Island, Kingston, RI, USA
- Department of Biomedical and Pharmaceutical Sciences, College of Pharmacy, University of Rhode Island, Kingston, RI, USA
- Interdisciplinary Neuroscience Program, University of Rhode Island, Kingston, RI, USA
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Steinbüchel M, Menne J, Schröter R, Neugebauer U, Schlatter E, Ciarimboli G. Regulation of Transporters for Organic Cations by High Glucose. Int J Mol Sci 2023; 24:14051. [PMID: 37762353 PMCID: PMC10531077 DOI: 10.3390/ijms241814051] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2023] [Revised: 09/08/2023] [Accepted: 09/11/2023] [Indexed: 09/29/2023] Open
Abstract
Endogenous positively charged organic substances, including neurotransmitters and cationic uremic toxins, as well as exogenous organic cations such as the anti-diabetic medication metformin, serve as substrates for organic cation transporters (OCTs) and multidrug and toxin extrusion proteins (MATEs). These proteins facilitate their transport across cell membranes. Vectorial transport through the OCT/MATE axis mediates the hepatic and renal excretion of organic cations, regulating their systemic and local concentrations. Organic cation transporters are part of the remote sensing and signaling system, whose activity can be regulated to cope with changes in the composition of extra- and intracellular fluids. Glucose, as a source of energy, can also function as a crucial signaling molecule, regulating gene expression in various organs and tissues. Its concentration in the blood may fluctuate in specific physiological and pathophysiological conditions. In this work, the regulation of the activity of organic cation transporters was measured by incubating human embryonic kidney cells stably expressing human OCT1 (hOCT1), hOCT2, or hMATE1 with high glucose concentrations (16.7 mM). Incubation with this high glucose concentration for 48 h significantly stimulated the activity of hOCT1, hOCT2, and hMATE1 by increasing their maximal velocity (Vmax), but without significantly changing their affinity for the substrates. These effects were independent of changes in osmolarity, as the addition of equimolar concentrations of mannitol did not alter transporter activity. The stimulation of transporter activity was associated with a significant increase in transporter mRNA expression. Inhibition of the mechanistic target of rapamycin (mTOR) kinase with Torin-1 suppressed the transporter stimulation induced by incubation with 16.7 mM glucose. Focusing on hOCT2, it was shown that incubation with 16.7 mM glucose increased hOCT2 protein expression in the plasma membrane. Interestingly, an apparent trend towards higher hOCT2 mRNA expression was observed in kidneys from diabetic patients, a pathology characterized by high serum glucose levels. Due to the small number of samples from diabetic patients (three), this observation must be interpreted with caution. In conclusion, incubation for 48 h with a high glucose concentration of 16.7 mM stimulated the activity and expression of organic cation transporters compared to those measured in the presence of 5.6 mM glucose. This stimulation by a diabetic environment could increase cellular uptake of the anti-diabetic drug metformin and increase renal tubular secretion of organic cations in an early stage of diabetes.
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Affiliation(s)
| | | | | | | | | | - Giuliano Ciarimboli
- Experimental Nephrology, Department of Internal Medicine D, University Hospital Münster, 48149 Münster, Germany; (M.S.); (J.M.); (R.S.); (U.N.); (E.S.)
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Zhang X, Wang L, Pan T, Wu X, Shen J, Jiang L, Tajima H, Blumwald E, Qiu QS. Plastid KEA-type cation/H + antiporters are required for vacuolar protein trafficking in Arabidopsis. J Integr Plant Biol 2023; 65:2157-2174. [PMID: 37252889 DOI: 10.1111/jipb.13537] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/03/2023] [Accepted: 05/28/2023] [Indexed: 06/01/2023]
Abstract
Arabidopsis plastid antiporters KEA1 and KEA2 are critical for plastid development, photosynthetic efficiency, and plant development. Here, we show that KEA1 and KEA2 are involved in vacuolar protein trafficking. Genetic analyses found that the kea1 kea2 mutants had short siliques, small seeds, and short seedlings. Molecular and biochemical assays showed that seed storage proteins were missorted out of the cell and the precursor proteins were accumulated in kea1 kea2. Protein storage vacuoles (PSVs) were smaller in kea1 kea2. Further analyses showed that endosomal trafficking in kea1 kea2 was compromised. Vacuolar sorting receptor 1 (VSR1) subcellular localizations, VSR-cargo interactions, and p24 distribution on the endoplasmic reticulum (ER) and Golgi apparatus were affected in kea1 kea2. Moreover, plastid stromule growth was reduced and plastid association with the endomembrane compartments was disrupted in kea1 kea2. Stromule growth was regulated by the cellular pH and K+ homeostasis maintained by KEA1 and KEA2. The organellar pH along the trafficking pathway was altered in kea1 kea2. Overall, KEA1 and KEA2 regulate vacuolar trafficking by controlling the function of plastid stromules via adjusting pH and K+ homeostasis.
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Affiliation(s)
- Xiao Zhang
- MOE Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou, 73000, China
- Academy of Plateau Science and Sustainability, School of Life Sciences, Qinghai Normal University, Xining, 810000, China
- College of Coastal Agricultural Sciences, Guangdong Ocean University, Zhanjiang, 524088, China
- State Key Laboratory of Herbage Improvement and Grassland Agro-ecosystems, Lanzhou University, Lanzhou, 730000, China
| | - Lu Wang
- MOE Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou, 73000, China
- Academy of Plateau Science and Sustainability, School of Life Sciences, Qinghai Normal University, Xining, 810000, China
- College of Coastal Agricultural Sciences, Guangdong Ocean University, Zhanjiang, 524088, China
- State Key Laboratory of Herbage Improvement and Grassland Agro-ecosystems, Lanzhou University, Lanzhou, 730000, China
| | - Ting Pan
- MOE Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou, 73000, China
| | - Xuexia Wu
- MOE Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou, 73000, China
| | - Jinbo Shen
- State Key Laboratory of Subtropical Silviculture, Zhejiang A&F University, Hangzhou, 311300, China
| | - Liwen Jiang
- School of Life Sciences, Centre for Cell & Developmental Biology and State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Hong Kong, China
| | - Hiromi Tajima
- Department of Plant Sciences, University of California, Davis, CA, 95616, USA
| | - Eduardo Blumwald
- Department of Plant Sciences, University of California, Davis, CA, 95616, USA
| | - Quan-Sheng Qiu
- MOE Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou, 73000, China
- Academy of Plateau Science and Sustainability, School of Life Sciences, Qinghai Normal University, Xining, 810000, China
- College of Coastal Agricultural Sciences, Guangdong Ocean University, Zhanjiang, 524088, China
- State Key Laboratory of Herbage Improvement and Grassland Agro-ecosystems, Lanzhou University, Lanzhou, 730000, China
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34
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Yu J, Li H, Fang T, Yun C, Liu X, Xu J, Jiang X, Cai X. Harnessing the Lysosomal Sorting Signals of the Cation-Independent Mannose-6-Phosphate Receptor for Targeted Degradation of Membrane Proteins. J Am Chem Soc 2023; 145:19107-19119. [PMID: 37552887 DOI: 10.1021/jacs.3c07687] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/10/2023]
Abstract
Membrane proteins are a crucial class of therapeutic targets that remain challenging to modulate using traditional occupancy-driven inhibition strategies or current proteolysis-targeting degradation approaches. Here, we report that the inherent endolysosomal sorting machinery can be harnessed for the targeted degradation of membrane proteins. A new degradation technique, termed signal-mediated lysosome-targeting chimeras (SignalTACs), was developed by genetically fusing the signaling motif from the cation-independent mannose-6-phosphate receptor (CI-M6PR) to a membrane protein binder. Antibody-based SignalTACs were constructed with the CI-M6PR signal peptides fused to the C-terminus of both heavy and light chains of IgG. We demonstrated the scope of this platform technology by degrading five pathogenesis-related membrane proteins, including HER2, EGFR, PD-L1, CD20, and CD71. Furthermore, two simplified constructs of SignalTACs, nanobody-based and peptide-based SignalTACs, were created and shown to promote the lysosomal degradation of target membrane proteins. Compared to the parent antibodies, SignalTACs exhibited significantly higher efficiency in inhibiting tumor cell growth both in vitro and in vivo. This work provides a simple, general, and robust strategy for degrading membrane proteins with molecular precision and may represent a powerful platform with broad research and therapeutic applications.
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Affiliation(s)
- Jinfeng Yu
- School of Pharmaceutical Sciences, Sun Yat-sen University, 132 East Outer Ring Road, Guangzhou 510006, China
| | - Haonan Li
- School of Pharmaceutical Sciences, Sun Yat-sen University, 132 East Outer Ring Road, Guangzhou 510006, China
| | - Tong Fang
- School of Pharmaceutical Sciences, Sun Yat-sen University, 132 East Outer Ring Road, Guangzhou 510006, China
| | - Chengyu Yun
- School of Pharmaceutical Sciences, Sun Yat-sen University, 132 East Outer Ring Road, Guangzhou 510006, China
| | - Xue Liu
- School of Pharmaceutical Sciences, Sun Yat-sen University, 132 East Outer Ring Road, Guangzhou 510006, China
| | - Jingyao Xu
- School of Pharmaceutical Sciences, Sun Yat-sen University, 132 East Outer Ring Road, Guangzhou 510006, China
| | - Xianxing Jiang
- School of Pharmaceutical Sciences, Sun Yat-sen University, 132 East Outer Ring Road, Guangzhou 510006, China
| | - Xiaoqing Cai
- School of Pharmaceutical Sciences, Sun Yat-sen University, 132 East Outer Ring Road, Guangzhou 510006, China
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35
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Gibson JS, Stewart GW. A critical role for altered red cell cation permeability in pathogenesis of sickle cell disease and other haemolytic anaemias. Br J Haematol 2023; 202:462-464. [PMID: 37096935 DOI: 10.1111/bjh.18832] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2023] [Revised: 04/13/2023] [Accepted: 04/14/2023] [Indexed: 04/26/2023]
Abstract
The aetiology of sickle cell disease is well known, but pathogenesis is complicated and details remain uncertain. A thorough understanding may suggest novel ways for designing more effective therapies. One area of importance, covered here in Nader et al., is the altered cation permeability of sickle cells and how the co-ordinated operation of a number of membrane transport proteins contributes to disease progression, all driven by the initial event of HbS polymerisation. There are echoes here of the cation leaks of hereditary stomatocytosis. Nader et al. propose a central role for PIEZO1, a novel mechanosensitive channel found in red cells, which may be aberrantly activated in sickle cells following HbS polymerisation and which may have potential as a novel target for future chemotherapies. Commentary on: Nader et al. Piezo1 activation augments sickling propensity and the adhesive properties of sickle red blood cells in a calcium-dependent manner. Br J Haematol 2023;202:657-668.
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Affiliation(s)
- John S Gibson
- Department of Veterinary Medicine, University of Cambridge, Cambridge, UK
| | - Gordon W Stewart
- Division of Medicine, Faculty of Medical Sciences, University College London, London, UK
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36
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Morizumi T, Kim K, Li H, Govorunova EG, Sineshchekov OA, Wang Y, Zheng L, Bertalan É, Bondar AN, Askari A, Brown LS, Spudich JL, Ernst OP. Structures of channelrhodopsin paralogs in peptidiscs explain their contrasting K + and Na + selectivities. Nat Commun 2023; 14:4365. [PMID: 37474513 PMCID: PMC10359266 DOI: 10.1038/s41467-023-40041-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2023] [Accepted: 07/07/2023] [Indexed: 07/22/2023] Open
Abstract
Kalium channelrhodopsin 1 from Hyphochytrium catenoides (HcKCR1) is a light-gated channel used for optogenetic silencing of mammalian neurons. It selects K+ over Na+ in the absence of the canonical tetrameric K+ selectivity filter found universally in voltage- and ligand-gated channels. The genome of H. catenoides also encodes a highly homologous cation channelrhodopsin (HcCCR), a Na+ channel with >100-fold larger Na+ to K+ permeability ratio. Here, we use cryo-electron microscopy to determine atomic structures of these two channels embedded in peptidiscs to elucidate structural foundations of their dramatically different cation selectivity. Together with structure-guided mutagenesis, we show that K+ versus Na+ selectivity is determined at two distinct sites on the putative ion conduction pathway: in a patch of critical residues in the intracellular segment (Leu69/Phe69, Ile73/Ser73 and Asp116) and within a cluster of aromatic residues in the extracellular segment (primarily, Trp102 and Tyr222). The two filters are on the opposite sides of the photoactive site involved in channel gating.
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Affiliation(s)
- Takefumi Morizumi
- Department of Biochemistry, University of Toronto, Toronto, ON, Canada
| | - Kyumhyuk Kim
- Department of Biochemistry, University of Toronto, Toronto, ON, Canada
| | - Hai Li
- Department of Biochemistry & Molecular Biology, Center for Membrane Biology, The University of Texas Health Science Center at Houston McGovern Medical School, Houston, TX, USA
| | - Elena G Govorunova
- Department of Biochemistry & Molecular Biology, Center for Membrane Biology, The University of Texas Health Science Center at Houston McGovern Medical School, Houston, TX, USA
| | - Oleg A Sineshchekov
- Department of Biochemistry & Molecular Biology, Center for Membrane Biology, The University of Texas Health Science Center at Houston McGovern Medical School, Houston, TX, USA
| | - Yumei Wang
- Department of Biochemistry & Molecular Biology, Center for Membrane Biology, The University of Texas Health Science Center at Houston McGovern Medical School, Houston, TX, USA
| | - Lei Zheng
- Department of Biochemistry & Molecular Biology, Center for Membrane Biology, The University of Texas Health Science Center at Houston McGovern Medical School, Houston, TX, USA
| | - Éva Bertalan
- Physikzentrum, RWTH-Aachen University, Aachen, Germany
| | - Ana-Nicoleta Bondar
- Faculty of Physics, University of Bucharest, Măgurele, Romania
- Institute of Computational Biomedicine (IAS-5/INM-9), Forschungszentrum Jülich, Jülich, Germany
| | - Azam Askari
- Department of Physics and Biophysics Interdepartmental Group, University of Guelph, Guelph, ON, Canada
| | - Leonid S Brown
- Department of Physics and Biophysics Interdepartmental Group, University of Guelph, Guelph, ON, Canada
| | - John L Spudich
- Department of Biochemistry & Molecular Biology, Center for Membrane Biology, The University of Texas Health Science Center at Houston McGovern Medical School, Houston, TX, USA.
| | - Oliver P Ernst
- Department of Biochemistry, University of Toronto, Toronto, ON, Canada.
- Department of Molecular Genetics, University of Toronto, Toronto, ON, Canada.
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Kuravi SJ, Ahmed NS, Taylor KA, Capes EM, Bye A, Unsworth AJ, Gibbins JM, Pugh N. Delineating Zinc Influx Mechanisms during Platelet Activation. Int J Mol Sci 2023; 24:11689. [PMID: 37511448 PMCID: PMC10380784 DOI: 10.3390/ijms241411689] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2023] [Revised: 07/07/2023] [Accepted: 07/13/2023] [Indexed: 07/30/2023] Open
Abstract
Zinc (Zn2+) is released by platelets during a hemostatic response to injury. Extracellular zinc ([Zn2+]o) initiates platelet activation following influx into the platelet cytosol. However, the mechanisms that permit Zn2+ influx are unknown. Fluctuations in intracellular zinc ([Zn2+]i) were measured in fluozin-3-loaded platelets using fluorometry and flow cytometry. Platelet activation was assessed using light transmission aggregometry. The detection of phosphoproteins was performed by Western blotting. [Zn2+]o influx and subsequent platelet activation were abrogated by blocking the sodium/calcium exchanged, TRP channels, and ZIP7. Cation store depletion regulated Zn2+ influx. [Zn2+]o stimulation resulted in the phosphorylation of PKC substates, MLC, and β3 integrin. Platelet activation via GPVI or Zn2+ resulted in ZIP7 phosphorylation in a casein kinase 2-dependent manner and initiated elevations of [Zn2+]i that were sensitive to the inhibition of Orai1, ZIP7, or IP3R-mediated pathways. These data indicate that platelets detect and respond to changes in [Zn2+]o via influx into the cytosol through TRP channels and the NCX exchanger. Platelet activation results in the externalization of ZIP7, which further regulates Zn2+ influx. Increases in [Zn2+]i contribute to the activation of cation-dependent enzymes. Sensitivity of Zn2+ influx to thapsigargin indicates a store-operated pathway that we term store-operated Zn2+ entry (SOZE). These mechanisms may affect platelet behavior during thrombosis and hemostasis.
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Affiliation(s)
- Sahithi J. Kuravi
- School of Life Sciences, Anglia Ruskin University, Cambridge CB1 1PT, UK (E.M.C.)
| | - Niaz S. Ahmed
- School of Life Sciences, Anglia Ruskin University, Cambridge CB1 1PT, UK (E.M.C.)
| | - Kirk A. Taylor
- Institute for Cardiovascular and Metabolic Research, School of Biological Sciences, University of Reading, Reading RG6 6EX, UK (J.M.G.)
| | - Emily M. Capes
- School of Life Sciences, Anglia Ruskin University, Cambridge CB1 1PT, UK (E.M.C.)
| | - Alex Bye
- Institute for Cardiovascular and Metabolic Research, School of Biological Sciences, University of Reading, Reading RG6 6EX, UK (J.M.G.)
| | - Amanda J. Unsworth
- Department of Life Sciences, Faculty of Science and Engineering, Manchester Metropolitan University, Manchester M1 5GD, UK
| | - Jonathan M. Gibbins
- Institute for Cardiovascular and Metabolic Research, School of Biological Sciences, University of Reading, Reading RG6 6EX, UK (J.M.G.)
| | - Nicholas Pugh
- School of Life Sciences, Anglia Ruskin University, Cambridge CB1 1PT, UK (E.M.C.)
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38
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Irie K, Oda Y, Sumikama T, Oshima A, Fujiyoshi Y. The structural basis of divalent cation block in a tetrameric prokaryotic sodium channel. Nat Commun 2023; 14:4236. [PMID: 37454189 PMCID: PMC10349818 DOI: 10.1038/s41467-023-39987-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2022] [Accepted: 07/06/2023] [Indexed: 07/18/2023] Open
Abstract
Divalent cation block is observed in various tetrameric ion channels. For blocking, a divalent cation is thought to bind in the ion pathway of the channel, but such block has not yet been directly observed. So, the behaviour of these blocking divalent cations remains still uncertain. Here, we elucidated the mechanism of the divalent cation block by reproducing the blocking effect into NavAb, a well-studied tetrameric sodium channel. Our crystal structures of NavAb mutants show that the mutations increasing the hydrophilicity of the inner vestibule of the pore domain enable a divalent cation to stack on the ion pathway. Furthermore, non-equilibrium molecular dynamics simulation showed that the stacking calcium ion repel sodium ion at the bottom of the selectivity filter. These results suggest the primary process of the divalent cation block mechanism in tetrameric cation channels.
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Affiliation(s)
- Katsumasa Irie
- Department of Biophysical Chemistry, School of Pharmaceutical Sciences, Wakayama Medical University, 25-1, Shichibancho, Wakayama, 640-8156, Japan.
- Cellular and Structural Physiology Institute (CeSPI), Nagoya University, Furo-cho, Chikusa, Nagoya, 464-8601, Japan.
| | - Yoshinori Oda
- Department of Basic Medicinal Sciences, Graduate School of Pharmaceutical Sciences, Nagoya University, Furo-cho, Chikusa, Nagoya, 464-8601, Japan
| | - Takashi Sumikama
- PRESTO, JST, Kawaguchi, 332-0012, Japan
- Nano Life Science Institute (WPI-NanoLSI), Kanazawa University, Kanazawa, 920-1192, Japan
| | - Atsunori Oshima
- Cellular and Structural Physiology Institute (CeSPI), Nagoya University, Furo-cho, Chikusa, Nagoya, 464-8601, Japan
- Department of Basic Medicinal Sciences, Graduate School of Pharmaceutical Sciences, Nagoya University, Furo-cho, Chikusa, Nagoya, 464-8601, Japan
- Institute for Glyco-core Research (iGCORE), Nagoya University, Furo-cho, Chikusa-ku, Nagoya, 464-8601, Japan
- Center for One Medicine Innovative Translational Research, Gifu University Institute for Advanced Study, Gifu, 501-11193, Japan
| | - Yoshinori Fujiyoshi
- Cellular and Structural Physiology Laboratory (CeSPL), Advanced Research Institute, Tokyo Medical and Dental University, 1-5-45, Yushima, Bunkyo, Tokyo, 113-8510, Japan
- CeSPIA Inc., 2-1-1, Otemachi, Chiyoda, Tokyo, 100-0004, Japan
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Szollosi A, Almássy J. Functional characterization of the transient receptor potential melastatin 2 (TRPM2) cation channel from Nematostella vectensis reconstituted into lipid bilayer. Sci Rep 2023; 13:11471. [PMID: 37454209 PMCID: PMC10349829 DOI: 10.1038/s41598-023-38640-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2023] [Accepted: 07/12/2023] [Indexed: 07/18/2023] Open
Abstract
Transient receptor potential melastatin 2 (TRPM2) cation channel activity is required for insulin secretion, immune cell activation and body heat control. Channel activation upon oxidative stress is involved in the pathology of stroke and neurodegenerative disorders. Cytosolic Ca2+, ADP-ribose (ADPR) and phosphatidylinositol-4,5-bisphosphate (PIP2) are the obligate activators of the channel. Several TRPM2 cryo-EM structures have been resolved to date, yet functionality of the purified protein has not been tested. Here we reconstituted overexpressed and purified TRPM2 from Nematostella vectensis (nvTRPM2) into lipid bilayers and found that the protein is fully functional. Consistent with the observations in native membranes, nvTRPM2 in lipid bilayers is co-activated by cytosolic Ca2+ and either ADPR or ADPR-2'-phosphate (ADPRP). The physiological metabolite ADPRP has a higher apparent affinity than ADPR. In lipid bilayers nvTRPM2 displays a large linear unitary conductance, its open probability (Po) shows little voltage dependence and is stable over several minutes. Po is high without addition of exogenous PIP2, but is largely blunted by treatment with poly-L-Lysine, a polycation that masks PIP2 headgroups. These results indicate that PIP2 or some other activating phosphoinositol lipid co-purifies with nvTRPM2, suggesting a high PIP2 binding affinity of nvTRPM2 under physiological conditions.
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Affiliation(s)
- Andras Szollosi
- Department of Biochemistry, Semmelweis University, Tuzolto u. 37-47, Budapest, 1094, Hungary.
- ELKH-SE Ion Channel Research Group, Semmelweis University, Tuzolto u. 37-47, Budapest, 1094, Hungary.
- HCEMM-SE Molecular Channelopathies Research Group, Semmelweis University, Tuzolto u. 37-47, Budapest, 1094, Hungary.
| | - János Almássy
- Department of Physiology, Semmelweis University, Tuzolto u. 37-47, Budapest, 1094, Hungary
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Al-Aqtash R, Ross MS, Collier DM. Extracellular histone proteins activate P2XR7 channel current. J Gen Physiol 2023; 155:e202213317. [PMID: 37199689 PMCID: PMC10200710 DOI: 10.1085/jgp.202213317] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2022] [Revised: 03/30/2023] [Accepted: 05/04/2023] [Indexed: 05/19/2023] Open
Abstract
Extracellular histone proteins are elevated in circulation after injury or activation of the innate immune response. In resistance-size arteries, extracellular histone proteins increased endothelial cell (EC) Ca2+ influx and propidium iodide (PI) labeling, but paradoxically decreased vasodilation. These observations could be explained by the activation of an EC resident non-selective cation channel. We tested the hypothesis that the ionotropic purinergic receptor 7 (P2XR7), a non-selective cation channel associated with cationic dye uptake, is activated by histone proteins. We expressed mouse P2XR7 (C57BL/6J variant 451L) in heterologous cells and measured inward cation current using two-electrode voltage clamp (TEVC). Cells expressing mouse P2XR7 had robust ATP- and histone-evoked inward cation currents. ATP- and histone-evoked currents reversed approximately at the same potential. Current decay with agonist removal was slower for histone-evoked than ATP- or BzATP-evoked currents. As with ATP-evoked P2XR7 currents, histone-evoked currents were inhibited by non-selective P2XR7 antagonists (Suramin, PPADS, and TNP-ATP). Selective P2XR7 antagonists, AZ10606120, A438079, GW791343, and AZ11645373, inhibited ATP-evoked P2XR7 currents but did not inhibit histone-evoked P2XR7 currents. As previously reported with ATP-evoked currents, histone-evoked P2XR7 currents were also increased in conditions of low extracellular Ca2+. These data demonstrate that P2XR7 is necessary and sufficient for histone-evoked inward cation currents in a heterologous expression system. These results provide insight into a new allosteric mechanism of P2XR7 activation by histone proteins.
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Affiliation(s)
- Rua’a Al-Aqtash
- Department of Pharmaceutical Sciences, University of Tennessee Health Science Center College of Pharmacy, Memphis, TN, USA
| | - Maxwell S. Ross
- Department of Pharmaceutical Sciences, University of Tennessee Health Science Center College of Pharmacy, Memphis, TN, USA
| | - Daniel M. Collier
- Department of Pharmaceutical Sciences, University of Tennessee Health Science Center College of Pharmacy, Memphis, TN, USA
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Qiao W, Richards CM, Jabs S. LYSET/TMEM251- a novel key component of the mannose 6-phosphate pathway. Autophagy 2023; 19:2143-2145. [PMID: 36633450 PMCID: PMC10283412 DOI: 10.1080/15548627.2023.2167376] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2022] [Revised: 01/06/2023] [Accepted: 01/06/2023] [Indexed: 01/13/2023] Open
Abstract
Degradation of macromolecules delivered to lysosomes by processes such as autophagy or endocytosis is crucial for cellular function. Lysosomes require more than 60 soluble hydrolases in order to catabolize such macromolecules. These soluble hydrolases are tagged with mannose6-phosphate (M6P) moieties in sequential reactions by the Golgi-resident GlcNAc-1-phosphotransferase complex and NAGPA/UCE/uncovering enzyme (N-acetylglucosamine-1-phosphodiester alpha-N-acetylglucosaminidase), which allows their delivery to endosomal/lysosomal compartments through trafficking mediated by cation-dependent and -independent mannose 6-phosphate receptors (MPRs). We and others recently identified TMEM251 as a novel regulator of the M6P pathway via independent genome-wide genetic screening strategies. We renamed TMEM251 to LYSET (lysosomal enzyme trafficking factor) to establish nomenclature reflective to this gene's function. LYSET is a Golgi-localized transmembrane protein important for the retention of the GlcNAc-1-phosphotransferase complex in the Golgi-apparatus. The current understanding of LYSET's importance regarding human biology is 3-fold: 1) highly pathogenic viruses that depend on lysosomal hydrolase activity require LYSET for infection. 2) The presence of LYSET is critical for cancer cell proliferation in nutrient-deprived environments in which extracellular proteins must be catabolized. 3) Inherited pathogenic alleles of LYSET can cause a severe inherited disease which resembles GlcNAc-1-phosphotransferase deficiency (i.e., mucolipidosis type II).Abbreviations: GlcNAc-1-PT: GlcNAc-1-phosphotransferase; KO: knockout; LSD: lysosomal storage disorder; LYSET: lysosomal enzyme trafficking factor; M6P: mannose 6-phosphate; MPRs: mannose-6-phosphate receptors, cation-dependent or -independent; MBTPS1/site-1 protease: membrane bound transcription factor peptidase, site 1; MLII: mucolipidosis type II; WT: wild-type.
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Affiliation(s)
- Wenjie Qiao
- Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, CA, USA
| | - Christopher M. Richards
- Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, CA, USA
| | - Sabrina Jabs
- Institute of Clinical Molecular Biology, Christian-Albrechts-University and University Medical Center Schleswig-Holstein, Campus Kiel, Kiel, Schleswig-Holstein, Germany
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42
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Suo Y, Wright NJ, Guterres H, Fedor JG, Butay KJ, Borgnia MJ, Im W, Lee SY. Molecular basis of polyspecific drug and xenobiotic recognition by OCT1 and OCT2. Nat Struct Mol Biol 2023; 30:1001-1011. [PMID: 37291422 PMCID: PMC10895701 DOI: 10.1038/s41594-023-01017-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2022] [Accepted: 05/04/2023] [Indexed: 06/10/2023]
Abstract
A wide range of endogenous and xenobiotic organic ions require facilitated transport systems to cross the plasma membrane for their disposition. In mammals, organic cation transporter (OCT) subtypes 1 and 2 (OCT1 and OCT2, also known as SLC22A1 and SLC22A2, respectively) are polyspecific transporters responsible for the uptake and clearance of structurally diverse cationic compounds in the liver and kidneys, respectively. Notably, it is well established that human OCT1 and OCT2 play central roles in the pharmacokinetics and drug-drug interactions of many prescription medications, including metformin. Despite their importance, the basis of polyspecific cationic drug recognition and the alternating access mechanism for OCTs have remained a mystery. Here we present four cryo-electron microscopy structures of apo, substrate-bound and drug-bound OCT1 and OCT2 consensus variants, in outward-facing and outward-occluded states. Together with functional experiments, in silico docking and molecular dynamics simulations, these structures uncover general principles of organic cation recognition by OCTs and provide insights into extracellular gate occlusion. Our findings set the stage for a comprehensive structure-based understanding of OCT-mediated drug-drug interactions, which will prove critical in the preclinical evaluation of emerging therapeutics.
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Affiliation(s)
- Yang Suo
- Department of Biochemistry, Duke University School of Medicine, Durham, NC, USA
| | - Nicholas J Wright
- Department of Biochemistry, Duke University School of Medicine, Durham, NC, USA
| | - Hugo Guterres
- Departments of Biological Sciences, Chemistry, and Bioengineering, Lehigh University, Bethlehem, PA, USA
| | - Justin G Fedor
- Department of Biochemistry, Duke University School of Medicine, Durham, NC, USA
| | - Kevin John Butay
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, Research Triangle Park, Durham, NC, USA
| | - Mario J Borgnia
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, Research Triangle Park, Durham, NC, USA
| | - Wonpil Im
- Departments of Biological Sciences, Chemistry, and Bioengineering, Lehigh University, Bethlehem, PA, USA
| | - Seok-Yong Lee
- Department of Biochemistry, Duke University School of Medicine, Durham, NC, USA.
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Yang L, Arbona RJR, Smith CS, Banks KM, Thomas VK, Palmer L, Evans T, Hurtado R. An evolutionarily conserved pacemaker role for HCN ion channels in smooth muscle. J Physiol 2023; 601:1225-1246. [PMID: 36930567 PMCID: PMC10065941 DOI: 10.1113/jp283701] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2022] [Accepted: 02/14/2023] [Indexed: 03/18/2023] Open
Abstract
Although hyperpolarization-activated cation (HCN) ion channels are well established to underlie cardiac pacemaker activity, their role in smooth muscle organs remains controversial. HCN-expressing cells are localized to renal pelvic smooth muscle (RPSM) pacemaker tissues of the murine upper urinary tract and HCN channel conductance is required for peristalsis. To date, however, the Ih pacemaker current conducted by HCN channels has never been detected in these cells, raising questions on the identity of RPSM pacemakers. Indeed, the RPSM pacemaker mechanisms of the unique multicalyceal upper urinary tract exhibited by humans remains unknown. Here, we developed immunopanning purification protocols and demonstrate that 96% of isolated HCN+ cells exhibit Ih . Single-molecule STORM to whole-tissue imaging showed HCN+ cells express single HCN channels on their plasma membrane and integrate into the muscular syncytium. By contrast, PDGFR-α+ cells exhibiting the morphology of ICC gut pacemakers were shown to be vascular mural cells. Translational studies in the homologous human and porcine multicalyceal upper urinary tracts showed that contractions and pacemaker depolarizations originate in proximal calyceal RPSM. Critically, HCN+ cells were shown to integrate into calyceal RPSM pacemaker tissues, and HCN channel block abolished electrical pacemaker activity and peristalsis of the multicalyceal upper urinary tract. Cumulatively, these studies demonstrate that HCN ion channels play a broad, evolutionarily conserved pacemaker role in both cardiac and smooth muscle organs and have implications for channelopathies as putative aetiologies of smooth muscle disorders. KEY POINTS: Pacemakers trigger contractions of involuntary muscles. Hyperpolarization-activated cation (HCN) ion channels underpin cardiac pacemaker activity, but their role in smooth muscle organs remains controversial. Renal pelvic smooth muscle (RPSM) pacemakers trigger contractions that propel waste away from the kidney. HCN+ cells localize to murine RPSM pacemaker tissue and HCN channel conductance is required for peristalsis. The HCN (Ih ) current has never been detected in RPSM cells, raising doubt whether HCN+ cells are bona fide pacemakers. Moreover, the pacemaker mechanisms of the unique multicalyceal RPSM of higher order mammals remains unknown. In total, 97% of purified HCN+ RPSM cells exhibit Ih . HCN+ cells integrate into the RPSM musculature, and pacemaker tissue peristalsis is dependent on HCN channels. Translational studies in human and swine demonstrate HCN channels are conserved in the multicalyceal RPSM and that HCN channels underlie pacemaker activity that drives peristalsis. These studies provide insight into putative channelopathies that can underlie smooth muscle dysfunction.
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Affiliation(s)
- Lei Yang
- Department of Physiology and Biophysics, Weill Medical College of Cornell University, New York, NY, USA
| | - Rodolfo J. Ricart Arbona
- Center of Comparative Medicine and Pathology, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Carl S. Smith
- Department of Urologic Surgery, University of Minnesota School of Medicine, Minneapolis, MN, USA
| | - Kelly M. Banks
- Department of Surgery, Weill Medical College of Cornell University, New York, NY, USA
| | - V. Kaye Thomas
- Bio-Imaging Resource Center, The Rockefeller University, New York, NY, USA
| | - Lawrence Palmer
- Department of Physiology and Biophysics, Weill Medical College of Cornell University, New York, NY, USA
| | - Todd Evans
- Department of Surgery, Weill Medical College of Cornell University, New York, NY, USA
| | - Romulo Hurtado
- Department of Surgery, Weill Medical College of Cornell University, New York, NY, USA
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Vallet A, Martin-Laffon J, Favier A, Revel B, Bonnot T, Vidaud C, Armengaud J, Gaillard JC, Delangle P, Devime F, Figuet S, Serre NBC, Erba EB, Brutscher B, Ravanel S, Bourguignon J, Alban C. The plasma membrane-associated cation-binding protein PCaP1 of Arabidopsis thaliana is a uranyl-binding protein. J Hazard Mater 2023; 446:130668. [PMID: 36608581 DOI: 10.1016/j.jhazmat.2022.130668] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/17/2022] [Revised: 12/14/2022] [Accepted: 12/23/2022] [Indexed: 06/17/2023]
Abstract
Uranium (U) is a naturally-occurring radionuclide that is toxic to living organisms. Given that proteins are primary targets of U(VI), their identification is an essential step towards understanding the mechanisms of radionuclide toxicity, and possibly detoxification. Here, we implemented a chromatographic strategy including immobilized metal affinity chromatography to trap protein targets of uranyl in Arabidopsis thaliana. This procedure allowed the identification of 38 uranyl-binding proteins (UraBPs) from root and shoot extracts. Among them, UraBP25, previously identified as plasma membrane-associated cation-binding protein 1 (PCaP1), was further characterized as a protein interacting in vitro with U(VI) and other metals using spectroscopic and structural approaches, and in planta through analyses of the fate of U(VI) in Arabidopsis lines with altered PCaP1 gene expression. Our results showed that recombinant PCaP1 binds U(VI) in vitro with affinity in the nM range, as well as Cu(II) and Fe(III) in high proportions, and that Ca(II) competes with U(VI) for binding. U(VI) induces PCaP1 oligomerization through binding at the monomer interface, at both the N-terminal structured domain and the C-terminal flexible region. Finally, U(VI) translocation in Arabidopsis shoots was affected in pcap1 null-mutant, suggesting a role for this protein in ion trafficking in planta.
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Affiliation(s)
- Alicia Vallet
- Univ. Grenoble Alpes, CEA, CNRS, IRIG, IBS, 38000 Grenoble, France
| | | | - Adrien Favier
- Univ. Grenoble Alpes, CEA, CNRS, IRIG, IBS, 38000 Grenoble, France
| | - Benoît Revel
- Univ. Grenoble Alpes, CNRS, CEA, INRAE, IRIG, LPCV, 38000 Grenoble, France
| | - Titouan Bonnot
- Univ. Grenoble Alpes, CNRS, CEA, INRAE, IRIG, LPCV, 38000 Grenoble, France
| | - Claude Vidaud
- BIAM, CEA, CNRS, Univ. Aix-Marseille, 13108 Saint-Paul-lez-Durance, France
| | - Jean Armengaud
- Département Médicaments et Technologies pour la Santé (DMTS), Université Paris-Saclay, CEA, INRAE, SPI, F-F-30200 Bagnols-sur-Cèze, France
| | - Jean-Charles Gaillard
- Département Médicaments et Technologies pour la Santé (DMTS), Université Paris-Saclay, CEA, INRAE, SPI, F-F-30200 Bagnols-sur-Cèze, France
| | - Pascale Delangle
- Univ. Grenoble Alpes, CEA, CNRS, GRE-INP, IRIG, SyMMES, 38000 Grenoble, France
| | - Fabienne Devime
- Univ. Grenoble Alpes, CNRS, CEA, INRAE, IRIG, LPCV, 38000 Grenoble, France
| | - Sylvie Figuet
- Univ. Grenoble Alpes, CNRS, CEA, INRAE, IRIG, LPCV, 38000 Grenoble, France
| | - Nelson B C Serre
- Univ. Grenoble Alpes, CNRS, CEA, INRAE, IRIG, LPCV, 38000 Grenoble, France
| | | | | | - Stéphane Ravanel
- Univ. Grenoble Alpes, CNRS, CEA, INRAE, IRIG, LPCV, 38000 Grenoble, France
| | | | - Claude Alban
- Univ. Grenoble Alpes, CNRS, CEA, INRAE, IRIG, LPCV, 38000 Grenoble, France.
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45
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Espinoza‐Corral R, Schwenkert S, Schneider A. Characterization of the preferred cation cofactors of chloroplast protein kinases in Arabidopsis thaliana. FEBS Open Bio 2023; 13:511-518. [PMID: 36683405 PMCID: PMC9989932 DOI: 10.1002/2211-5463.13563] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2022] [Revised: 01/09/2023] [Accepted: 01/20/2023] [Indexed: 01/24/2023] Open
Abstract
Chloroplasts sense a variety of stimuli triggering several acclimation responses. One prominent response is the mechanism of state transitions, which enables rapid adaption to changes in illumination. Here, we investigated the link between divalent cations (calcium, magnesium, and manganese) and protein kinase activity in Arabidopsis chloroplasts. Our results show that manganese ions are the strongest activator of kinase activity in chloroplasts followed by magnesium ions, whereas calcium ions are not able to induce kinase activity. Additionally, the phosphorylation of specific protein bands is strongly reduced in chloroplasts of a cmt1 mutant, which is impaired in manganese import into chloroplasts, as compared to the wild-type. These findings provide insights for the future characterization of chloroplast protein kinase activity and potential target proteins.
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Affiliation(s)
| | - Serena Schwenkert
- Plant Molecular Biology, Faculty of BiologyLudwig Maximilians University MunichPlaneggGermany
| | - Anja Schneider
- Plant Molecular Biology, Faculty of BiologyLudwig Maximilians University MunichPlaneggGermany
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46
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Fields M, Marcuzzi A, Gonelli A, Celeghini C, Maximova N, Rimondi E. Mitochondria-Targeted Antioxidants, an Innovative Class of Antioxidant Compounds for Neurodegenerative Diseases: Perspectives and Limitations. Int J Mol Sci 2023; 24:ijms24043739. [PMID: 36835150 PMCID: PMC9960436 DOI: 10.3390/ijms24043739] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2022] [Revised: 02/06/2023] [Accepted: 02/11/2023] [Indexed: 02/15/2023] Open
Abstract
Neurodegenerative diseases comprise a wide spectrum of pathologies characterized by progressive loss of neuronal functions and structures. Despite having different genetic backgrounds and etiology, in recent years, many studies have highlighted a point of convergence in the mechanisms leading to neurodegeneration: mitochondrial dysfunction and oxidative stress have been observed in different pathologies, and their detrimental effects on neurons contribute to the exacerbation of the pathological phenotype at various degrees. In this context, increasing relevance has been acquired by antioxidant therapies, with the purpose of restoring mitochondrial functions in order to revert the neuronal damage. However, conventional antioxidants were not able to specifically accumulate in diseased mitochondria, often eliciting harmful effects on the whole body. In the last decades, novel, precise, mitochondria-targeted antioxidant (MTA) compounds have been developed and studied, both in vitro and in vivo, to address the need to counter the oxidative stress in mitochondria and restore the energy supply and membrane potentials in neurons. In this review, we focus on the activity and therapeutic perspectives of MitoQ, SkQ1, MitoVitE and MitoTEMPO, the most studied compounds belonging to the class of MTA conjugated to lipophilic cations, in order to reach the mitochondrial compartment.
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Affiliation(s)
- Matteo Fields
- Department of Translational Medicine, University of Ferrara, 44121 Ferrara, Italy
| | - Annalisa Marcuzzi
- Department of Translational Medicine, University of Ferrara, 44121 Ferrara, Italy
- Correspondence:
| | - Arianna Gonelli
- Department of Environmental and Prevention Sciences, University of Ferrara, 44121 Ferrara, Italy
| | - Claudio Celeghini
- Department of Translational Medicine, University of Ferrara, 44121 Ferrara, Italy
| | - Natalia Maximova
- Department of Pediatrics, Pediatrics, Bone Marrow Transplant Unit, Institute for Maternal and Child Health-IRCCS Burlo Garofolo, 34137 Trieste, Italy
| | - Erika Rimondi
- Department of Translational Medicine and LTTA Centre, University of Ferrara, 44121 Ferrara, Italy
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Bala N, Yu L, Liu LP, Shelton L, Xu Y, Ghayee HK, Alli AA. Metabolic Characterization and Glyceraldehyde-3-Phosphate Dehydrogenase-Dependent Regulation of Epithelial Sodium Channels in hPheo1 Wild-type and SDHB Knockdown Cells. Endocrinology 2023; 164:7034155. [PMID: 36763043 DOI: 10.1210/endocr/bqad026] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/22/2022] [Revised: 01/26/2023] [Accepted: 01/30/2023] [Indexed: 02/11/2023]
Abstract
Pheochromocytomas (PCC) and paragangliomas (PGL) are rare neuroendocrine tumors with limited curative treatment options outside of surgical resection. Patients with mutations in succinate dehydrogenase subunit B (SDHB) are at an increased risk of malignant and aggressive disease. As cation channels are associated with tumorigenesis, we studied the expression and activity of cation channels from the Degenerin superfamily in a progenitor cell line derived from a human PCC. hPheo1 wild-type (WT) and SDHB knockdown (KD) cells were studied to investigate whether epithelial sodium channels (ENaC) and acid-sensing ion channels (ASIC) are regulated by the activity of glyceraldehyde-3-phosphate dehydrogenase (GAPDH). First, we performed targeted metabolomic studies and quantified changes in glycolysis pathway intermediates and citric acid cycle intermediates using hPheo1 WT cells and SDHB KD cells. Next, we performed protein biochemistry and electrophysiology studies to characterize the protein expression and activity, respectively, of these ion channels. Our western blot experiments show both ENaC alpha and ASIC1/2 are expressed in both hPheo1 WT and SDHB KD cells, with lower levels of a cleaved 60 kDa form of ENaC in SDHB KD cells. Single-channel patch clamp studies corroborate these results and further indicate channel activity is decreased in SDHB KD cells. Additional experiments showed a more significant decreased membrane potential in SDHB KD cells, which were sensitive to amiloride compared to WT cells. We provide evidence for the differential expression and activity of ENaC and ASIC hybrid channels in hPheo1 WT and SDHB KD cells, providing an important area of investigation in understanding SDHB-related disease.
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Affiliation(s)
- Niharika Bala
- Department of Physiology and Aging, University of Florida College of Medicine, Gainesville, FL, USA
| | - Ling Yu
- Department of Physiology and Aging, University of Florida College of Medicine, Gainesville, FL, USA
| | - Lauren P Liu
- Department of Physiology and Aging, University of Florida College of Medicine, Gainesville, FL, USA
| | | | - Yiling Xu
- Department of Medicine, Division of Endocrinology & Metabolism, University of Florida College of Medicine, Gainesville, FL, USA
| | - Hans K Ghayee
- Department of Medicine, Division of Endocrinology & Metabolism, University of Florida College of Medicine, Gainesville, FL, USA
- Malcom Randall VA Medical Center, Gainesville, FL, USA
| | - Abdel A Alli
- Department of Physiology and Aging, University of Florida College of Medicine, Gainesville, FL, USA
- Department of Medicine Division of Nephrology, Hypertension, and Renal Transplantation, University of Florida College of Medicine, Gainesville, FL, USA
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48
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Yunaini L, Erlina L, Fadilah F, Pujianto DA. In silico docking analysis of beta-defensin 20 against cation channel sperm-associated protein 1-4 to predict its role in the sperm maturation. Asian J Androl 2023; 25:528-532. [PMID: 36571327 PMCID: PMC10411257 DOI: 10.4103/aja2022103] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2022] [Accepted: 11/16/2022] [Indexed: 12/27/2022] Open
Abstract
Beta-defensin 20 (DEFB20) is widely expressed in the epididymis with gene features involved in epididymal sperm maturation. However, the action mechanism and function of DEFB20 in sperm maturation are still unclear. One of the important roles of beta-defensin is the ion channel activity. The cation channel sperm-associated protein (CatSper) alpha is an ion channel protein found on the sperm surface. This study aimed to investigate the interaction between DEFB20 and CatSper1-4 protein in relation to the sperm maturation process. Protein sequences were obtained from the National Center for Biotechnology Information (NCBI). Protein modeling and validation were carried out by using the Robetta modeling server and the Ramachandran plot method. Rosetta web server was used for the docking analysis. The results revealed a natural interaction between DEFB20 and CatSper1-4. The interaction occurred at the cation channel (close to the casein kinase II), ion transport protein, and kinase c phosphorylation of the CatSper1-4 active site. The DEFB20 region interacting with CatSper2-4 was the beta-defensin domain, while with CatSper1 was the non-beta-defensin domain. Based on the analysis, DEFB20 may interact with CatSper α subunits, particularly CatsSper1, to affect ion channel activity during sperm maturation.
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Affiliation(s)
- Luluk Yunaini
- Doctoral Program for Biomedical Sciences, Faculty of Medicine, Universitas Indonesia, Jakarta 10430, Indonesia
- Department of Medical Biology, Faculty of Medicine, Universitas Indonesia, Jakarta 10430, Indonesia
| | - Linda Erlina
- Department of Medical Chemistry, Faculty of Medicine, Universitas Indonesia, Jakarta 10430, Indonesia
- Bioinformatics Core Facilities, Indonesia Medical Education and Research Institute (IMERI), Faculty of Medicine, Universitas Indonesia, Jakarta 10430, Indonesia
| | - Fadilah Fadilah
- Department of Medical Chemistry, Faculty of Medicine, Universitas Indonesia, Jakarta 10430, Indonesia
- Bioinformatics Core Facilities, Indonesia Medical Education and Research Institute (IMERI), Faculty of Medicine, Universitas Indonesia, Jakarta 10430, Indonesia
| | - Dwi Ari Pujianto
- Department of Medical Biology, Faculty of Medicine, Universitas Indonesia, Jakarta 10430, Indonesia
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Nawaly H, Matsui H, Tsuji Y, Iwayama K, Ohashi H, Nakajima K, Matsuda Y. Multiple plasma membrane SLC4s contribute to external HCO3- acquisition during CO2 starvation in the marine diatom Phaeodactylum tricornutum. J Exp Bot 2023; 74:296-307. [PMID: 36124754 DOI: 10.1093/jxb/erac380] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/15/2022] [Accepted: 09/16/2022] [Indexed: 06/15/2023]
Abstract
The availability of CO2 is one of the restrictions on aquatic photosynthesis. Solute carrier (SLC) 4-2, a plasma membrane HCO3- transporter has previously been identified in the marine diatom Phaeodactylum tricornutum. In this study, we discovered two paralogs, PtSLC4-1 and PtSLC4-4, that are both localized at the plasma membrane. Their overexpression stimulated HCO3- uptake, and this was inhibited by the anion channel blocker 4,4´-diisothiocyanostilbene-2,2´-disulfonic (DIDS). Similarly to SLC4-2, PtSLC4-1 specifically required Na+ of ~100 mM for its maximum HCO3- transport activity. Unlike PtSLC4-1 and PtSLC4-2, the HCO3- transport of PtSLC4-4 depended equally on Na+, K+, or Li+, suggesting its broad selectivity for cations. Transcript analyses indicated that PtSLC4-1 was the most abundant HCO3- transporter under CO2 concentrations below atmospheric levels, while PtSLC4-4 showed little transcript induction under atmospheric CO2 but transient induction to comparable levels to PtSLC4-1 during the initial acclimation stage from high CO2 (1%) to very low CO2 (<0.002%). Our results strongly suggest a major HCO3- transport role of PtSLC4-1 with a relatively minor role of PtSLC4-2, and that PtSLC4-4 operates under severe CO2 limitation unselectively to cations when the other SLC4s do not function to support HCO3- uptake.
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Affiliation(s)
- Hermanus Nawaly
- Department of Bioscience, School of Science and Technology, Kwansei Gakuin University, 1 Gakuen Uegahara, Sanda, Hyogo, 669-1330, Japan
| | - Hiroaki Matsui
- Department of Bioscience, School of Science and Technology, Kwansei Gakuin University, 1 Gakuen Uegahara, Sanda, Hyogo, 669-1330, Japan
| | - Yoshinori Tsuji
- Department of Bioscience, School of Science and Technology, Kwansei Gakuin University, 1 Gakuen Uegahara, Sanda, Hyogo, 669-1330, Japan
- Graduate School of Biostudies, Kyoto University, Kyoto 606-8502, Japan
| | - Kazufumi Iwayama
- Department of Bioscience, School of Science and Technology, Kwansei Gakuin University, 1 Gakuen Uegahara, Sanda, Hyogo, 669-1330, Japan
| | - Hiroki Ohashi
- Department of Bioscience, School of Science and Technology, Kwansei Gakuin University, 1 Gakuen Uegahara, Sanda, Hyogo, 669-1330, Japan
| | - Kensuke Nakajima
- Department of Bioscience, School of Science and Technology, Kwansei Gakuin University, 1 Gakuen Uegahara, Sanda, Hyogo, 669-1330, Japan
| | - Yusuke Matsuda
- Department of Bioscience, School of Science and Technology, Kwansei Gakuin University, 1 Gakuen Uegahara, Sanda, Hyogo, 669-1330, Japan
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50
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Wu D, Xu L, Cai WM, Zhan SY, Wan G, Xu Y, Shi YS. A splicing-dependent ER retention signal regulates surface expression of the mechanosensitive TMEM63B cation channel. J Biol Chem 2022; 299:102781. [PMID: 36496074 PMCID: PMC9830214 DOI: 10.1016/j.jbc.2022.102781] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2022] [Revised: 11/25/2022] [Accepted: 11/29/2022] [Indexed: 12/12/2022] Open
Abstract
TMEM63B is a mechanosensitive cation channel activated by hypoosmotic stress and mechanic stimulation. We recently reported a brain-specific alternative splicing of exon 4 in TMEM63B. The short variant lacking exon 4, which constitutes the major isoform in the brain, exhibits enhanced responses to hypoosmotic stimulation compared to the long isoform containing exon 4. However, the mechanisms affecting this differential response are unclear. Here, we showed that the short isoform exhibited stronger cell surface expression compared to the long variant. Using mutagenesis screening of the coding sequence of exon 4, we identified an RXR-type endoplasmic reticulum (ER) retention signal (RER). We found that this motif was responsible for binding to the COPI retrieval vesicles, such that the longer TMEM63B isoforms were more likely to be retrotranslocated to the ER than the short isoforms. In addition, we demonstrated long TMEM63Bs could form heterodimers with short isoforms and reduce their surface expression. Taken together, our findings revealed an ER retention signal in the alternative splicing domain of TMEM63B that regulates the surface expression of TMEM63B protein and channel function.
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Affiliation(s)
- Dan Wu
- Department of Neurology, Drum Tower Hospital, Ministry of Education Key -Laboratory of Model Animal for Disease Study, Model Animal Research Center, Jiangsu Key Laboratory of Molecular Medicine, Medical School, Nanjing University, Nanjing, China; Guangdong Institute of Intelligence Science and Technology, Zhuhai, China
| | - Lushan Xu
- Department of Neurology, Drum Tower Hospital, Ministry of Education Key -Laboratory of Model Animal for Disease Study, Model Animal Research Center, Jiangsu Key Laboratory of Molecular Medicine, Medical School, Nanjing University, Nanjing, China; Clinical College of Traditional Chinese and Western Medicine, Nanjing University of Chinese Medicine, Nanjing, China
| | - Wen-Min Cai
- Department of Neurology, Drum Tower Hospital, Ministry of Education Key -Laboratory of Model Animal for Disease Study, Model Animal Research Center, Jiangsu Key Laboratory of Molecular Medicine, Medical School, Nanjing University, Nanjing, China
| | - Shi-Yu Zhan
- Department of Neurology, Drum Tower Hospital, Ministry of Education Key -Laboratory of Model Animal for Disease Study, Model Animal Research Center, Jiangsu Key Laboratory of Molecular Medicine, Medical School, Nanjing University, Nanjing, China
| | - Guoqiang Wan
- Department of Neurology, Drum Tower Hospital, Ministry of Education Key -Laboratory of Model Animal for Disease Study, Model Animal Research Center, Jiangsu Key Laboratory of Molecular Medicine, Medical School, Nanjing University, Nanjing, China; Institute for Brain Sciences, Nanjing University, Nanjing, China
| | - Yun Xu
- Department of Neurology, Drum Tower Hospital, Ministry of Education Key -Laboratory of Model Animal for Disease Study, Model Animal Research Center, Jiangsu Key Laboratory of Molecular Medicine, Medical School, Nanjing University, Nanjing, China; Institute for Brain Sciences, Nanjing University, Nanjing, China.
| | - Yun Stone Shi
- Department of Neurology, Drum Tower Hospital, Ministry of Education Key -Laboratory of Model Animal for Disease Study, Model Animal Research Center, Jiangsu Key Laboratory of Molecular Medicine, Medical School, Nanjing University, Nanjing, China; Guangdong Institute of Intelligence Science and Technology, Zhuhai, China; Institute for Brain Sciences, Nanjing University, Nanjing, China.
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