1
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Sackin H, Nanazashvili M. A phenylalanine at the extracellular side of Kir1.1 facilitates potassium permeation. Channels (Austin) 2024; 18:2294661. [PMID: 38184795 PMCID: PMC10773671 DOI: 10.1080/19336950.2023.2294661] [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: 09/01/2023] [Accepted: 12/08/2023] [Indexed: 01/08/2024] Open
Abstract
The Kir1.1 (ROMK) family of weak inward rectifiers controls K secretion in the renal CCT and K recycling in the renal TALH. A single point mutant of the inward rectifier, F127V-Kir1.1b was used to investigate the K transition between the selectivity filter and the outer mouth of the channel. We hypothesize that normally an aromatic Phe at the external entryway of Kir1.1b facilitates outward K secretion. We tested this by replacing F127-Kir1.1b with a small aliphatic Val. Results indicate that removal of the Phe at 127 suppresses outward currents that normally contribute to K secretion. Results with the F127V mutant could be explained by increased polyamine block and/or a decrease in the avidity of Kir1.1 for K ions near the outer mouth of the channel. The latter is supported by F127V-Kir1.1b having a lower affinity (Km = 33 mM) for K than wild-type Kir1.1b (Km = 7 mM) during external K elevation. Conversely, chelation of K with 18-Crown-6 ether reduced K conductance faster in F127V (half-time = 6s) than in wt-Kir1.1b (half-time = 120s), implying that F127V is less hospitable to external K. In other experiments, positive membrane potentials gated the F127V mutant channel closed at physiological levels of external Ca, possibly by electrostatically depleting K adjacent to the membrane, suggesting that the Phe residue is critical for outward K secretion at physiological Ca. We speculate that the avidity of wt-Kir1.1b for external K could result from a cation-Pi interaction between K and the aromatic F127.
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Affiliation(s)
- Henry Sackin
- Department of Physiology and Biophysics and Center for Proteomics and Molecular Therapeutics, Chicago Medical School, Rosalind Franklin University, North Chicago, IL, USA
| | - Mikheil Nanazashvili
- Department of Physiology and Biophysics and Center for Proteomics and Molecular Therapeutics, Chicago Medical School, Rosalind Franklin University, North Chicago, IL, USA
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2
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Cheng J, Wang W, Zhang J, Wan S, Cheng B, Yu J, Cao S. Molecularly Tunable Heterostructured Co-polymers Containing Electron-deficient and -rich Moieties for Visible-light and Sacrificial-agent-free H2O2 Photosynthesis. Angew Chem Int Ed Engl 2024:e202406310. [PMID: 38712550 DOI: 10.1002/anie.202406310] [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] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2024] [Revised: 04/29/2024] [Accepted: 05/06/2024] [Indexed: 05/08/2024]
Abstract
As an alternative to hydrogen peroxide (H2O2) production by complex anthraquinone oxidation process, photosynthesis of H2O2 from water and oxygen without sacrificial agents is highly demanded. Herein, a covalently connected molecular heterostructure is synthesized via sequential C-H arylation and Knoevenagel polymerization reactions for visible-light and sacrificial-agent-free H2O2 synthesis. The subsequent copolymerization of the electron-deficient benzodithiophene-4,8-dione and the electron-rich biphenyl (B) and p-phenylenediacetonitrile (CN) not only expands the π-conjugated domain but also increases the molecular dipole moment, which largely promotes the separation and transfer of the photoinduced charge carriers. The optimal heterostructured BTDB-CN0.2 manifested an impressive photocatalytic H2O2 production rate of 1920 μmol g-1 h-1, which is 2.2 and 11.6 times that of BTDB and BTDCN. As revealed by the femtosecond transient absorption (fs-TA) and theoretical calculations, the linkage serves as a channel for the rapid transfer of photogenerated charge carriers, enhancing the photocatalytic efficiency. Further, in situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) uncovers that the oxygen reduction reaction occurs through the step one-electron pathway and the mutual conversion between C=O and C-OH with the anchoring of H+ during the catalysis favored the formation of H2O2. This work provides a novel perspective for the design of efficient organic photocatalysts.
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Affiliation(s)
- Jingzhao Cheng
- Wuhan University of Technology, State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Wuhan, CHINA
| | - Wang Wang
- Wuhan University of Technology, State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Wuhan, CHINA
| | - Jianjun Zhang
- China University of Geosciences, Laboratory of Solar Fuel, Faculty of Materials Science and Chemistry, Wuhan, CHINA
| | - Sijie Wan
- Wuhan University of Technology, State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Wuhan, CHINA
| | - Bei Cheng
- Wuhan University of Technology, State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Wuhan, CHINA
| | - Jiaguo Yu
- China University of Geosciences, Laboratory of Solar Fuel, Faculty of Materials Science and Chemistry, Wuhan, CHINA
| | - Shaowen Cao
- Wuhan University of Technology, State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, 122 Luoshi Road, 430070, Wuhan, CHINA
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3
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Kirilov N. Comparison of the Performance of the Fast Healthcare Interoperability Resources (FHIR) Subscription Channels. Stud Health Technol Inform 2024; 313:143-148. [PMID: 38682520 DOI: 10.3233/shti240027] [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] [Indexed: 05/01/2024]
Abstract
BACKGROUND The Fast Health Interoperability Resources (FHIR) standard was proposed and released to solve the interoperability problems of the electronic health records. The FHIR Subscription resources are used to establish real-time event notifications from the FHIR server to another system. There are several communication channels such as rest-hook and websocket. The objective of our work is to compare the performance of the FHIR subscription using the rest-hook and websocket channels. METHODS HAPI FHIR server, python websocket clients and HTTP endpoints were used to measure the processor and memory usage of the two subscription channels. Tests were performed with 5, 10, 15, 20, 30, 40, 50, 60, 70 and 80 clients. The performance was logged using windows performance monitor. RESULTS The rest-hook subscription showed near six-fold increase in resource utilization when increasing the clients from 5 to 80. On the contrary, the websocket subscription channel did not reach a two-fold increase. CONCLUSION The type of the subscription channel should be carefully selected and load distribution should be considered when the number of clients grows.
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Affiliation(s)
- Nikola Kirilov
- Institute of Medical Informatics, Heidelberg University Hospital, Germany
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4
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Pavlenok M, Nair RR, Hendrickson RC, Niederweis M. The C-terminus is essential for the stability of the mycobacterial channel protein MspA. Protein Sci 2024; 33:e4912. [PMID: 38358254 PMCID: PMC10868439 DOI: 10.1002/pro.4912] [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: 06/26/2023] [Revised: 12/15/2023] [Accepted: 01/10/2024] [Indexed: 02/16/2024]
Abstract
Outer membrane proteins perform essential functions in uptake and secretion processes in bacteria. MspA is an octameric channel protein in the outer membrane of Mycobacterium smegmatis and is structurally distinct from any other known outer membrane protein. MspA is the founding member of a family with more than 3000 homologs and is one of the most widely used proteins in nanotechnological applications due to its advantageous pore structure and extraordinary stability. While a conserved C-terminal signal sequence is essential for folding and protein assembly in the outer membrane of Gram-negative bacteria, the molecular determinants of these processes are unknown for MspA. In this study, we show that mutation and deletion of methionine 183 in the highly conserved C-terminus of MspA and mutation of the conserved tryptophan 40 lead to a complete loss of protein in heat extracts of M. smegmatis. Swapping these residues partially restores the heat stability of MspA indicating that methionine 183 and tryptophan 40 form a conserved sulfur-π electron interaction, which stabilizes the MspA monomer. Flow cytometry showed that all MspA mutants are surface-accessible demonstrating that oligomerization and membrane integration in M. smegmatis are not affected. Thus, the conserved C-terminus of MspA is essential for its thermal stability, but it is not required for protein assembly in its native membrane, indicating that this process is mediated by a mechanism distinct from that in Gram-negative bacteria. These findings will benefit the rational design of MspA-like pores to tailor their properties in current and future applications.
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Affiliation(s)
- Mikhail Pavlenok
- Department of MicrobiologyUniversity of Alabama at BirminghamBirminghamAlabamaUSA
| | | | | | - Michael Niederweis
- Department of MicrobiologyUniversity of Alabama at BirminghamBirminghamAlabamaUSA
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5
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Hu YT, Hong XZ, Li HM, Yang JK, Shen W, Wang YW, Liu YH. Modifying the amino acids in conformational motion pathway of the α-amylase of Geobacillus stearothermophilus improved its activity and stability. Front Microbiol 2023; 14:1261245. [PMID: 38143856 PMCID: PMC10740195 DOI: 10.3389/fmicb.2023.1261245] [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] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2023] [Accepted: 11/21/2023] [Indexed: 12/26/2023] Open
Abstract
Amino acids along the conformational motion pathway of the enzyme molecule correlated to its flexibility and rigidity. To enhance the enzyme activity and thermal stability, the motion pathway of Geobacillus stearothermophilus α-amylase has been identified and molecularly modified by using the neural relational inference model and deep learning tool. The significant differences in substrate specificity, enzymatic kinetics, optimal temperature, and thermal stability were observed among the mutants with modified amino acids along the pathway. Mutants especially the P44E demonstrated enhanced hydrolytic activity and catalytic efficiency (kcat/KM) than the wild-type enzyme to 95.0% and 93.8% respectively, with the optimum temperature increased to 90°C. This mutation from proline to glutamic acid has increased the number and the radius of the bottleneck of the channels, which might facilitate transporting large starch substrates into the enzyme. The mutation could also optimize the hydrogen bonding network of the catalytic center, and diminish the spatial hindering to the substrate entry and exit from the catalytic center.
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Affiliation(s)
- Yu-Ting Hu
- Pilot Base of Food Microbial Resources Utilization of Hubei Province, College of Life Science and Technology, Wuhan Polytechnic University, Wuhan, China
| | - Xi-Zhi Hong
- Pilot Base of Food Microbial Resources Utilization of Hubei Province, College of Life Science and Technology, Wuhan Polytechnic University, Wuhan, China
| | - Hui-Min Li
- Pilot Base of Food Microbial Resources Utilization of Hubei Province, College of Life Science and Technology, Wuhan Polytechnic University, Wuhan, China
| | - Jiang-Ke Yang
- Pilot Base of Food Microbial Resources Utilization of Hubei Province, College of Life Science and Technology, Wuhan Polytechnic University, Wuhan, China
| | - Wei Shen
- Pilot Base of Food Microbial Resources Utilization of Hubei Province, College of Life Science and Technology, Wuhan Polytechnic University, Wuhan, China
| | - Ya-Wei Wang
- Pilot Base of Food Microbial Resources Utilization of Hubei Province, College of Life Science and Technology, Wuhan Polytechnic University, Wuhan, China
| | - Yi-Han Liu
- Key Laboratory of Industrial Fermentation Microbiology, Ministry of Education, Tianjin Key Laboratory of Industrial Microbiology, The College of Biotechnology, Tianjin University of Science and Technology, Tianjin, China
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6
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Coppola T, Daziano G, Legroux I, Béraud-Dufour S, Blondeau N, Lebrun P. Unlocking Therapeutic Synergy: Tailoring Drugs for Comorbidities such as Depression and Diabetes through Identical Molecular Targets in Different Cell Types. Cells 2023; 12:2768. [PMID: 38067196 PMCID: PMC10706795 DOI: 10.3390/cells12232768] [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] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2023] [Revised: 11/24/2023] [Accepted: 12/01/2023] [Indexed: 12/18/2023] Open
Abstract
Research in the field of pharmacology aims to generate new treatments for pathologies. Nowadays, there are an increased number of chronic disorders that severely and durably handicap many patients. Among the most widespread pathologies, obesity, which is often associated with diabetes, is constantly increasing in incidence, and in parallel, neurodegenerative and mood disorders are increasingly affecting many people. For years, these pathologies have been so frequently observed in the population in a concomitant way that they are considered as comorbidities. In fact, common mechanisms are certainly at work in the etiology of these pathologies. The main purpose of this review is to show the value of anticipating the effect of baseline treatment of a condition on its comorbidity in order to obtain concomitant positive actions. One of the implications would be that by understanding and targeting shared molecular mechanisms underlying these conditions, it may be possible to tailor drugs that address both simultaneously. To this end, we firstly remind readers of the close link existing between depression and diabetes and secondly address the potential benefit of the pleiotropic actions of two major active molecules used to treat central and peripheral disorders, first a serotonin reuptake inhibitor (Prozac ®) and then GLP-1R agonists. In the second part, by discussing the therapeutic potential of new experimental antidepressant molecules, we will support the concept that a better understanding of the intracellular signaling pathways targeted by pharmacological agents could lead to future synergistic treatments targeting solely positive effects for comorbidities.
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Affiliation(s)
- Thierry Coppola
- CNRS, IPMC, Université Côte d’Azur, Sophia Antipolis, F-06560 Valbonne, France; (G.D.); (I.L.); (S.B.-D.); (N.B.)
| | | | | | | | | | - Patricia Lebrun
- CNRS, IPMC, Université Côte d’Azur, Sophia Antipolis, F-06560 Valbonne, France; (G.D.); (I.L.); (S.B.-D.); (N.B.)
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7
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Chen R, Gao X, Nie T, Wu J, Wang L, Osman A, Feng Y, Li X, Zhang Y. Crystal structure of the GDSL family esterase EstL5 in complex with PMSF reveals a branch channel of the active site pocket. Acta Biochim Biophys Sin (Shanghai) 2023; 55:1833-1839. [PMID: 37705347 PMCID: PMC10686790 DOI: 10.3724/abbs.2023108] [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: 02/28/2023] [Accepted: 05/19/2023] [Indexed: 09/15/2023] Open
Abstract
Esterases/lipases from the GDSL family have potential applications in the hydrolysis and synthesis of important esters of pharmaceutical, food, and biotechnical interests. However, the structural and functional understanding of GDSL enzymes is still limited. Here, we report the crystal structure of the GDSL family esterase EstL5 complexed with PMSF at 2.34 Å resolution. Intriguingly, the PMSF binding site is not located at the active site pocket but is situated in a surface cavity. At the active site, we note that there is a trapped crystallization solvent 1,6-hexanediol, which mimics the bound ester chain, allowing for further definition of the active site pocket of EstL5. The most striking structural feature of EstL5 is the presence of a unique channel, which extends approximately 18.9 Å, with a bottleneck radius of 6.8 Å, connecting the active-site pocket and the surface cavity. Replacement of Ser205 with the bulk aromatic residue Trp or Phe could partially block the channel at one end and perturb its access. Reduced enzymatic activity is found in the EstL5 S205W and EstL5 S205F mutants, suggesting the functional relevance of the channel to enzyme catalysis. Our study provides valuable information regarding the properties of the GDSL-family enzymes for designing more efficient and robust biocatalysts.
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Affiliation(s)
- Runsha Chen
- School of Food and BioengineeringChangsha University of Science & TechnologyChangsha410004China
| | - Xuechun Gao
- State Key Laboratory of Microbial MetabolismJoint International Research Laboratory of Metabolic and Developmental SciencesSchool of Life Sciences and BiotechnologyShanghai Jiao Tong UniversityShanghai200240China
| | - Ting Nie
- State Key Laboratory of Microbial MetabolismJoint International Research Laboratory of Metabolic and Developmental SciencesSchool of Life Sciences and BiotechnologyShanghai Jiao Tong UniversityShanghai200240China
| | - Jinhong Wu
- Department of Food Science and TechnologySchool of Agriculture and BiologyShanghai Jiao Tong UniversityShanghai200024China
| | - Lin Wang
- Gastro Endoscopy CenterShanghai Children’s HospitalSchool of MedicineShanghai Jiao Tong UniversityShanghai200062China
| | - Ali Osman
- Biochemistry DepartmentFaculty of AgricultureZagazig UniversityZagazigEgypt
| | - Yan Feng
- State Key Laboratory of Microbial MetabolismJoint International Research Laboratory of Metabolic and Developmental SciencesSchool of Life Sciences and BiotechnologyShanghai Jiao Tong UniversityShanghai200240China
| | - Xianghong Li
- School of Food and BioengineeringChangsha University of Science & TechnologyChangsha410004China
| | - Yong Zhang
- State Key Laboratory of Microbial MetabolismJoint International Research Laboratory of Metabolic and Developmental SciencesSchool of Life Sciences and BiotechnologyShanghai Jiao Tong UniversityShanghai200240China
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8
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Lai LTF, Balaraman J, Zhou F, Matthies D. Cryo-EM structures of human magnesium channel MRS2 reveal gating and regulatory mechanisms. bioRxiv 2023:2023.08.22.553867. [PMID: 37662257 PMCID: PMC10473633 DOI: 10.1101/2023.08.22.553867] [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] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/05/2023]
Abstract
Magnesium ions (Mg2+) play an essential role in cellular physiology. In mitochondria, protein and ATP synthesis and various metabolic pathways are directly regulated by Mg2+. MRS2, a magnesium channel located in the inner mitochondrial membrane, mediates the influx of Mg2+ into the mitochondrial matrix and regulates Mg2+ homeostasis. Knockdown of MRS2 in human cells leads to reduced uptake of Mg2+ into mitochondria and disruption of the mitochondrial metabolism. Despite the importance of MRS2, the Mg2+ translocation and regulation mechanisms of MRS2 are still unclear. Here, using cryo-EM we determined the structure of human MRS2 in the presence and absence of Mg2+ at 2.8 Å and 3.3 Å, respectively. From the homo-pentameric structures, we identified R332 and M336 as major gating residues, which were then tested using mutagenesis and two cellular divalent ion uptake assays. A network of hydrogen bonds was found connecting the gating residue R332 to the soluble domain, potentially regulating the gate. Two Mg2+-binding sites were identified in the MRS2 soluble domain, distinct from the two sites previously reported in CorA, a homolog of MRS2 in prokaryotes. Altogether, this study provides the molecular basis for understanding the Mg2+ translocation and regulatory mechanisms of MRS2.
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Affiliation(s)
- Louis Tung Faat Lai
- Unit on Structural Biology, Division of Basic and Translational Biophysics, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda MD 20892, USA
| | - Jayashree Balaraman
- Unit on Structural Biology, Division of Basic and Translational Biophysics, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda MD 20892, USA
| | - Fei Zhou
- Unit on Structural Biology, Division of Basic and Translational Biophysics, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda MD 20892, USA
| | - Doreen Matthies
- Unit on Structural Biology, Division of Basic and Translational Biophysics, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda MD 20892, USA
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9
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Medrano E, Collins KM. Muscle-directed mechanosensory feedback activates egg-laying circuit activity and behavior in Caenorhabditis elegans. Curr Biol 2023; 33:2330-2339.e8. [PMID: 37236183 PMCID: PMC10280788 DOI: 10.1016/j.cub.2023.05.008] [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] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2022] [Revised: 03/29/2023] [Accepted: 05/03/2023] [Indexed: 05/28/2023]
Abstract
Mechanosensory feedback of the internal reproductive state drives decisions about when and where to reproduce.1 For instance, stretch in the Drosophila reproductive tract produced by artificial distention or from accumulated eggs regulates the attraction to acetic acid to ensure optimal oviposition.2 How such mechanosensory feedback modulates neural circuits to coordinate reproductive behaviors is incompletely understood. We previously identified a stretch-dependent homeostat that regulates egg laying in Caenorhabditis elegans. Sterilized animals lacking eggs show reduced Ca2+ transient activity in the presynaptic HSN command motoneurons that drive egg-laying behavior, while animals forced to accumulate extra eggs show dramatically increased circuit activity that restores egg laying.3 Interestingly, genetic ablation or electrical silencing of the HSNs delays, but does not abolish, the onset of egg laying,3,4,5 with animals recovering vulval muscle Ca2+ transient activity upon egg accumulation.6 Using an acute gonad microinjection technique to mimic changes in pressure and stretch resulting from germline activity and egg accumulation, we find that injection rapidly stimulates Ca2+ activity in both neurons and muscles of the egg-laying circuit. Injection-induced vulval muscle Ca2+ activity requires L-type Ca2+ channels but is independent of presynaptic input. Conversely, injection-induced neural activity is disrupted in mutants lacking the vulval muscles, suggesting "bottom-up" feedback from muscles to neurons. Direct mechanical prodding activates the vulval muscles, suggesting that they are the proximal targets of the stretch-dependent stimulus. Our results show that egg-laying behavior in C. elegans is regulated by a stretch-dependent homeostat that scales postsynaptic muscle responses with egg accumulation in the uterus.
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Affiliation(s)
- Emmanuel Medrano
- Department of Biology, University of Miami, 1301 Memorial Drive, Coral Gables, FL 33146, USA
| | - Kevin M Collins
- Department of Biology, University of Miami, 1301 Memorial Drive, Coral Gables, FL 33146, USA.
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10
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Rubio C, Gallardo N, Mena V, Rubio-Osornio M. The Participation of Ca2+ Channels in Epilepsy: A Bibliometric Analysis of the Scientific Literature in Latin America. CNS Neurol Disord Drug Targets 2023:CNSNDDT-EPUB-131902. [PMID: 37202887 DOI: 10.2174/1871527322666230518115952] [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] [Subscribe] [Scholar Register] [Received: 12/03/2022] [Revised: 04/03/2023] [Accepted: 04/10/2023] [Indexed: 05/20/2023]
Abstract
BACKGROUND Bibliometric analysis allows us to quantify and evaluate scientific activity, and it has become increasingly important in all areas of scientific literature. Thanks to these analyses, we can infer where science should put greater efforts into elucidating the underlying mechanisms of diseases that have yet to be fully described or investigated. OBJECTIVE This paper delves into published articles related to the involvement of calcium (Ca2+) channels in epilepsy, which is a condition with a high prevalence in Latin America. METHODS We followed the scientific publication on SCOPUS and analyzed the impact of publications from Latin America in the field of epilepsy and the study of Ca2+ channels. We identified the countries with the largest number of publications and found that 68% of them were experimental (animal models), while 32% were clinical. We also identified the main journals, growth over time, and citation numbers. RESULTS We found a total of 226 works produced by Latin American countries from 1976 to 2022. The countries that have contributed the most to the topic are Brazil, Mexico, and Argentina, with occasional collaborations between them to make contributions to the study of epilepsy and Ca2+ channels. Additionally, we found that the journal with the most citations is Nature Genetics. CONCLUSION The number of authors per article ranges from 1 to 242, and neuroscience journals are the preferred target for researchers, with a predilection for publishing original articles, although 26% of the publications are review articles.
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Affiliation(s)
- Carmen Rubio
- Departamento de Neurofisiología, Instituto Nacional de Neurología y Neurocirugía "MVS" Ciudad de México. México
| | - Noel Gallardo
- Departamento de Neurofisiología, Instituto Nacional de Neurología y Neurocirugía "MVS" Ciudad de México. México
- Benemérita Universidad Autónoma de Puebla. Facultad de Medicina, Puebla. México
| | - Vanessa Mena
- Departamento de Neurofisiología, Instituto Nacional de Neurología y Neurocirugía "MVS" Ciudad de México. México
- Universidad Autónoma de Baja California; Unidad Valle Dorado, Escuela de Ciencias de la Salud, Baja California. México
| | - Moisés Rubio-Osornio
- Departamento de Neuroquímica, Instituto Nacional de Neurología y Neurocirugía "MVS" Ciudad de México. México
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11
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Yun C. A Channel Allocation Method Considering the Asymmetry of Available Channels for Centralized Underwater Cognitive Acoustic Networks. Sensors (Basel) 2023; 23:3320. [PMID: 36992031 PMCID: PMC10056429 DOI: 10.3390/s23063320] [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] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/09/2023] [Revised: 03/20/2023] [Accepted: 03/20/2023] [Indexed: 06/19/2023]
Abstract
Due to the unpredictable presence of Non-Cognitive Users (NCUs) in the time and frequency domains, the number of available channels (i.e., channels where no NCUs exist) and corresponding channel indices per Cognitive User (CU) may differ. In this paper, we propose a heuristic channel allocation method referred to as Enhanced Multi-Round Resource Allocation (EMRRA), which employs the asymmetry of available channels in existing MRRA to randomly allocate a CU to a channel in each round. EMRRA is designed to enhance the overall spectral efficiency and fairness of channel allocation. To do this, the available channel with the lowest redundancy is primarily selected upon allocating a channel to a CU. In addition, when there are multiple CUs with the same allocation priority, the CU with the smallest number of available channels is chosen. We execute extensive simulations in order to investigate the effect of the asymmetry of available channels on CUs and compare the performance of EMRRA to that of MRRA. As a result, in addition to the asymmetry of available channels, it is confirmed that most of the channels are simultaneously available to multiple CUs. Furthermore, EMRRA outperforms MRRA in terms of the channel allocation rate, fairness, and drop rate and has a slightly higher collision rate. In particular, EMRRA can remarkably reduce the drop rate compared to MRRA.
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Affiliation(s)
- Changho Yun
- Korea Research Institute of Ships & Ocean Engineering (KRISO), Daejeon 34103, Republic of Korea
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12
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Ghosh M, Denkert N, Reuter M, Klümper J, Reglinski K, Peschel R, Schliebs W, Erdmann R, Meinecke M. Dynamics of the translocation pore of the human peroxisomal protein import machinery. Biol Chem 2023; 404:169-178. [PMID: 35977096 DOI: 10.1515/hsz-2022-0170] [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] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2022] [Accepted: 07/05/2022] [Indexed: 01/15/2023]
Abstract
Peroxisomal matrix proteins are synthesized on cytosolic ribosomes and imported in a posttranslational manner. Intricate protein import machineries have evolved that catalyze the different stages of translocation. In humans, PEX5L was found to be an essential component of the peroxisomal translocon. PEX5L is the main receptor for substrate proteins carrying a peroxisomal targeting signal (PTS). Substrates are bound by soluble PEX5L in the cytosol after which the cargo-receptor complex is recruited to peroxisomal membranes. Here, PEX5L interacts with the docking protein PEX14 and becomes part of an integral membrane protein complex that facilitates substrate translocation into the peroxisomal lumen in a still unknown process. In this study, we show that PEX5L containing complexes purified from human peroxisomal membranes constitute water-filled pores when reconstituted into planar-lipid membranes. Channel characteristics were highly dynamic in terms of conductance states, selectivity and voltage- and substrate-sensitivity. Our results show that a PEX5L associated pore exists in human peroxisomes, which can be activated by receptor-cargo complexes.
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Affiliation(s)
- Mausumi Ghosh
- Biochemistry Center (BZH), Heidelberg University, D-69120 Heidelberg, Germany.,Institute for Cellular Biochemistry, University Medical Center Göttingen, D-37073 Göttingen, Germany
| | - Niels Denkert
- Biochemistry Center (BZH), Heidelberg University, D-69120 Heidelberg, Germany.,Institute for Cellular Biochemistry, University Medical Center Göttingen, D-37073 Göttingen, Germany
| | - Maren Reuter
- Institute of Biochemistry and Pathobiochemistry, Ruhr University Bochum, D-44780 Bochum, Germany
| | - Jessica Klümper
- Institute of Biochemistry and Pathobiochemistry, Ruhr University Bochum, D-44780 Bochum, Germany
| | - Katharina Reglinski
- Institute of Biochemistry and Pathobiochemistry, Ruhr University Bochum, D-44780 Bochum, Germany
| | - Rebecca Peschel
- Institute of Biochemistry and Pathobiochemistry, Ruhr University Bochum, D-44780 Bochum, Germany
| | - Wolfgang Schliebs
- Institute of Biochemistry and Pathobiochemistry, Ruhr University Bochum, D-44780 Bochum, Germany
| | - Ralf Erdmann
- Institute of Biochemistry and Pathobiochemistry, Ruhr University Bochum, D-44780 Bochum, Germany
| | - Michael Meinecke
- Biochemistry Center (BZH), Heidelberg University, D-69120 Heidelberg, Germany.,Institute for Cellular Biochemistry, University Medical Center Göttingen, D-37073 Göttingen, Germany
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13
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Gvozdarev AS, Alishchuk AM, Kazakova MA. Closed-Form Capacity Reliability Analysis of Multiuser MIMO System in the Presence of Generalized Multipath Fading. Sensors (Basel) 2023; 23:2289. [PMID: 36850885 PMCID: PMC9966666 DOI: 10.3390/s23042289] [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] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/16/2022] [Revised: 02/10/2023] [Accepted: 02/17/2023] [Indexed: 06/18/2023]
Abstract
This research studies the problem of a joint capacity/capacity reliability analysis of the multiuser multi-input multioutput (MIMO) system functioning in the presence of generalized multipath fading. The study presents the derived results of the closed-form analytical statistical description of the ergodic sum-rate capacity, the capacity reliability and the capacity's higher-order statistics in the case of complex Nakagami-m distributed channel transmission coefficients. A numerical verification of the derived expressions was performed, and it demonstrated excellent correspondence with the simulation. The system performance was evaluated with the help of a numerical analysis of the joint first- and second-order statistics description, depending on the channel and system parameters. The results demonstrated several peculiarities, e.g., the existence of a specific extremum of the capacity reliability for small-sized MIMO systems, its opposite behavior (in terms of the varying number of antenna elements) for heavy and light fading, and the existing asymptotic regions of the system and the channel parameters.
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14
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Abstract
Nitrogen (N) is an essential macronutrient for plants and profoundly affects crop yields and qualities. Ammonium (NH4 + ) and nitrate (NO3 - ) are major inorganic N forms absorbed by plants from the surrounding environments. Intriguingly, NH4 + is usually toxic to plants when it serves as the sole or dominant N source. It is thus important for plants to coordinate the utilization of NH4 + and the alleviation of NH4 + toxicity. To fully decipher the molecular mechanisms underlying how plants minimize NH4 + toxicity may broadly benefit agricultural practice. In the current minireview, we attempt to discuss recent discoveries in the strategies for mitigating NH4 + toxicity in plants, which may provide potential solutions for improving the nitrogen use efficiency (NUE) and stress adaptions in crops.
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Affiliation(s)
- Chengbin Xiao
- Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou, 730000, China
- State Key Laboratory of Grassland Agro-Ecosystems, College of Pastoral Agriculture Science and Technology, Lanzhou University, Lanzhou, 730000, China
| | - Yuan Fang
- Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou, 730000, China
| | - Suomin Wang
- State Key Laboratory of Grassland Agro-Ecosystems, College of Pastoral Agriculture Science and Technology, Lanzhou University, Lanzhou, 730000, China
| | - Kai He
- Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou, 730000, China
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15
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Martucci LL, Launay JM, Kawakami N, Sicard C, Desvignes N, Dakouane-Giudicelli M, Spix B, Têtu M, Gilmaire FO, Paulcan S, Callebert J, Vaillend C, Bracher F, Grimm C, Fossier P, de la Porte S, Sakamoto H, Morris J, Galione A, Granon S, Cancela JM. Endolysosomal TPCs regulate social behavior by controlling oxytocin secretion. Proc Natl Acad Sci U S A 2023; 120:e2213682120. [PMID: 36745816 PMCID: PMC9963339 DOI: 10.1073/pnas.2213682120] [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] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2022] [Accepted: 12/14/2022] [Indexed: 02/08/2023] Open
Abstract
Oxytocin (OT) is a prominent regulator of many aspects of mammalian social behavior and stored in large dense-cored vesicles (LDCVs) in hypothalamic neurons. It is released in response to activity-dependent Ca2+ influx, but is also dependent on Ca2+ release from intracellular stores, which primes LDCVs for exocytosis. Despite its importance, critical aspects of the Ca2+-dependent mechanisms of its secretion remain to be identified. Here we show that lysosomes surround dendritic LDCVs, and that the direct activation of endolysosomal two-pore channels (TPCs) provides the critical Ca2+ signals to prime OT release by increasing the releasable LDCV pool without directly stimulating exocytosis. We observed a dramatic reduction in plasma OT levels in TPC knockout mice, and impaired secretion of OT from the hypothalamus demonstrating the importance of priming of neuropeptide vesicles for activity-dependent release. Furthermore, we show that activation of type 1 metabotropic glutamate receptors sustains somatodendritic OT release by recruiting TPCs. The priming effect could be mimicked by a direct application of nicotinic acid adenine dinucleotide phosphate, the endogenous messenger regulating TPCs, or a selective TPC2 agonist, TPC2-A1-N, or blocked by the antagonist Ned-19. Mice lacking TPCs exhibit impaired maternal and social behavior, which is restored by direct OT administration. This study demonstrates an unexpected role for lysosomes and TPCs in controlling neuropeptide secretion, and in regulating social behavior.
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Affiliation(s)
- Lora L. Martucci
- Neuroscience Paris-Saclay Institute, CNRS UMR 9197, Paris-Sud University, Paris-Saclay University, Saclay91400, France
- Université Paris-Saclay, Université de Versailles Saint-Quentin-en-Yvelines, Inserm, Evolution of Neuromuscular Diseases: Innovative Concepts and Practices, Versailles78000, France
- Department of Pharmacology, University of Oxford, OxfordOX1 3QT, UK
| | | | - Natsuko Kawakami
- Ushimado Marine Institute, Graduate School of Natural Science and Technology, Okayama University, Ushimado, Setouchi, Okayama701-4303, Japan
| | - Cécile Sicard
- Neuroscience Paris-Saclay Institute, CNRS UMR 9197, Paris-Sud University, Paris-Saclay University, Saclay91400, France
| | - Nathalie Desvignes
- Neuroscience Paris-Saclay Institute, CNRS UMR 9197, Paris-Sud University, Paris-Saclay University, Saclay91400, France
| | - Mbarka Dakouane-Giudicelli
- Université Paris-Saclay, Université de Versailles Saint-Quentin-en-Yvelines, Inserm, Evolution of Neuromuscular Diseases: Innovative Concepts and Practices, Versailles78000, France
| | - Barbara Spix
- Walther Straub Institute of Pharmacology and Toxicology, Faculty of Medicine Ludwig-Maximilians-University, Munich80336, Germany
| | - Maude Têtu
- Neuroscience Paris-Saclay Institute, CNRS UMR 9197, Paris-Sud University, Paris-Saclay University, Saclay91400, France
| | - Franck-Olivier Gilmaire
- Neuroscience Paris-Saclay Institute, CNRS UMR 9197, Paris-Sud University, Paris-Saclay University, Saclay91400, France
| | - Sloane Paulcan
- Neuroscience Paris-Saclay Institute, CNRS UMR 9197, Paris-Sud University, Paris-Saclay University, Saclay91400, France
| | - Jacques Callebert
- Laboratoire de Biochimie et Biologie Moléculaire, Hôpital Lariboisière, Paris75010, France
- Inserm UMR-S 1144 Universités Paris Descartes-Paris Diderot, Optimisation Thérapeutique en Neuropsychopharmacologie - Faculté des Sciences Pharmaceutiques et Biologiques, Paris Descartes,ParisParis 75006, France
| | - Cyrille Vaillend
- Neuroscience Paris-Saclay Institute, CNRS UMR 9197, Paris-Sud University, Paris-Saclay University, Saclay91400, France
| | - Franz Bracher
- Department of Pharmacy - Center for Drug Research, Ludwig-Maximilians University, Munich81377, Germany
| | - Christian Grimm
- Walther Straub Institute of Pharmacology and Toxicology, Faculty of Medicine Ludwig-Maximilians-University, Munich80336, Germany
| | - Philippe Fossier
- Neuroscience Paris-Saclay Institute, CNRS UMR 9197, Paris-Sud University, Paris-Saclay University, Saclay91400, France
| | - Sabine de la Porte
- Université Paris-Saclay, Université de Versailles Saint-Quentin-en-Yvelines, Inserm, Evolution of Neuromuscular Diseases: Innovative Concepts and Practices, Versailles78000, France
| | - Hirotaka Sakamoto
- Ushimado Marine Institute, Graduate School of Natural Science and Technology, Okayama University, Ushimado, Setouchi, Okayama701-4303, Japan
| | - John Morris
- Department of Physiology, Anatomy & Genetics, University of Oxford, OxfordOX1 3QX, UK
| | - Antony Galione
- Department of Pharmacology, University of Oxford, OxfordOX1 3QT, UK
| | - Sylvie Granon
- Neuroscience Paris-Saclay Institute, CNRS UMR 9197, Paris-Sud University, Paris-Saclay University, Saclay91400, France
| | - José-Manuel Cancela
- Neuroscience Paris-Saclay Institute, CNRS UMR 9197, Paris-Sud University, Paris-Saclay University, Saclay91400, France
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16
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Heo P, Culver JA, Miao J, Pincet F, Mariappan M. The Get1/2 insertase forms a channel to mediate the insertion of tail-anchored proteins into the ER. Cell Rep 2023; 42:111921. [PMID: 36640319 PMCID: PMC9932932 DOI: 10.1016/j.celrep.2022.111921] [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] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Revised: 11/07/2022] [Accepted: 12/13/2022] [Indexed: 12/29/2022] Open
Abstract
Tail-anchored (TA) proteins contain a single C-terminal transmembrane domain (TMD) that is captured by the cytosolic Get3 in yeast (TRC40 in humans). Get3 delivers TA proteins to the Get1/2 complex for insertion into the endoplasmic reticulum (ER) membrane. How Get1/2 mediates insertion of TMDs of TA proteins into the membrane is poorly understood. Using bulk fluorescence and microfluidics assays, we show that Get1/2 forms an aqueous channel in reconstituted bilayers. We estimate the channel diameter to be ∼2.5 nm wide, corresponding to the circumference of two Get1/2 complexes. We find that the Get3 binding can seal the Get1/2 channel, which dynamically opens and closes. Our mutation analysis further shows that the Get1/2 channel activity is required to release TA proteins from Get3 for insertion into the membrane. Hence, we propose that the Get1/2 channel functions as an insertase for insertion of TMDs and as a translocase for translocation of C-terminal hydrophilic segments.
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Affiliation(s)
- Paul Heo
- Laboratoire de Physique de l'Ecole Normale Supérieure, ENS, Université PSL, CNRS, Sorbonne Université, Université de Paris, 75005 Paris, France; Institute of Psychiatry and Neuroscience of Paris, INSERM U1266, 75014 Paris, France.
| | - Jacob A. Culver
- Department of Cell Biology, Yale School of Medicine, 333 Cedar Street, New Haven, CT 06520, USA,Nanobiology Institute, Yale University West Campus, West Haven, CT 06516, USA
| | - Jennifer Miao
- Department of Cell Biology, Yale School of Medicine, 333 Cedar Street, New Haven, CT 06520, USA,Nanobiology Institute, Yale University West Campus, West Haven, CT 06516, USA
| | - Frederic Pincet
- Laboratoire de Physique de l'Ecole Normale Supérieure, ENS, Université PSL, CNRS, Sorbonne Université, Université de Paris, 75005 Paris, France.
| | - Malaiyalam Mariappan
- Department of Cell Biology, Yale School of Medicine, 333 Cedar Street, New Haven, CT 06520, USA; Nanobiology Institute, Yale University West Campus, West Haven, CT 06516, USA.
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17
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Tan L, Waqas M, Rehman A, Rashid MAR, Fiaz S, Manzoor H, Azeem F. Computational analysis and expression profiling of potassium transport-related gene families in mango ( Mangifera indica) indicate their role in stress response and fruit development. Front Plant Sci 2023; 13:1102201. [PMID: 36756234 PMCID: PMC9899903 DOI: 10.3389/fpls.2022.1102201] [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] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/18/2022] [Accepted: 12/21/2022] [Indexed: 06/18/2023]
Abstract
Mango (Mangifera indica) fruit is known for its taste, health benefits, and drought tolerance. Potassium (K+) is one of the most abundant ions in a plant cell. It is important for various biological functions related to plant growth, development, and flowering/fruiting. It significantly contributes to fruit yield, quality, and drought tolerance in plants. However, molecular mechanisms comprising K+ transport in mango are least known. In the present study, 37 members of K+ transport-related genes (PTGs) were identified in mango, which include 22 K+ transporters (16 HAKs, 1 HKT, and 6 KEAs) and 15 K+ channels (6 TPKs and 8 Shakers). All PTGs were predicted to be expressed at the plasma membrane and possess characteristic motifs and domains. Phylogenetic analysis identified a strong kinship of PTGs among Oryza sativa, Arabidopsis thaliana, Cicer arietinum, Malus domestica, and M. indica. The promoter analysis identified 60 types of cis-elements related to various biological processes. RNA-seq-based expression profiling identified that MiTPK1.2, MiHAK1, MiHAK2.1, HAK6.1, and MiAKT1.1 were most upregulated in roots and that MiKEA2, MiAKT2, and MiAKT1 were upregulated in leaves. Moreover, MiAKT6, MiHAK1.1, MiKAT2, MiKAT2.1, MiHKT1, MiTPK1.1, MiHAK7, and MiHAK12 were highly expressed during the five growth stages of mango fruit. The current study is the first comprehensive report on K+ transport system in tropical fruits. Therefore, it will provide the foundation knowledge for the functional characterization of K+ genes in mango and related plants.
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Affiliation(s)
- Lin Tan
- Haikou Experimental Station, Chinese Academy of Tropical Agricultural Sciences, Haikou, Hainan, China
| | - Muhammad Waqas
- Department of Bioinformatics and Biotechnology, Government College University, Faisalabad, Pakistan
| | - Abdul Rehman
- Department of Bioinformatics and Biotechnology, Government College University, Faisalabad, Pakistan
| | | | - Sajid Fiaz
- Department of Plant Breeding and Genetics, The University of Haripur, Haripur, Pakistan
| | - Hamid Manzoor
- Institute of Molecular Biology and Biotechnology, Bahauddin Zakariya University, Multan, Pakistan
| | - Farrukh Azeem
- Department of Bioinformatics and Biotechnology, Government College University, Faisalabad, Pakistan
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18
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Alvear-Arias JJ, Pena-Pichicoi A, Carrillo C, Fernandez M, Gonzalez T, Garate JA, Gonzalez C. Role of voltage-gated proton channel (Hv1) in cancer biology. Front Pharmacol 2023; 14:1175702. [PMID: 37153807 PMCID: PMC10157179 DOI: 10.3389/fphar.2023.1175702] [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] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2023] [Accepted: 04/11/2023] [Indexed: 05/10/2023] Open
Abstract
The acid-base characteristics of tumor cells and the other elements that compose the tumor microenvironment have been topics of scientific interest in oncological research. There is much evidence confirming that pH conditions are maintained by changes in the patterns of expression of certain proton transporters. In the past decade, the voltage-gated proton channel (Hv1) has been added to this list and is increasingly being recognized as a target with onco-therapeutic potential. The Hv1 channel is key to proton extrusion for maintaining a balanced cytosolic pH. This protein-channel is expressed in a myriad of tissues and cell lineages whose functions vary from producing bioluminescence in dinoflagellates to alkalizing spermatozoa cytoplasm for reproduction, and regulating the respiratory burst for immune system response. It is no wonder that in acidic environments such as the tumor microenvironment, an exacerbated expression and function of this channel has been reported. Indeed, multiple studies have revealed a strong relationship between pH balance, cancer development, and the overexpression of the Hv1 channel, being proposed as a marker for malignancy in cancer. In this review, we present data that supports the idea that the Hv1 channel plays a significant role in cancer by maintaining pH conditions that favor the development of malignancy features in solid tumor models. With the antecedents presented in this bibliographic report, we want to strengthen the idea that the Hv1 proton channel is an excellent therapeutic strategy to counter the development of solid tumors.
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Affiliation(s)
- Juan J. Alvear-Arias
- Centro Interdisciplinario de Neurociencia de Valparaíso, Universidad de Valparaíso, Valparaíso, Chile
- Millennium Nucleus in NanoBioPhysics, Universidad de Valparaíso, Valparaíso, Chile
| | - Antonio Pena-Pichicoi
- Centro Interdisciplinario de Neurociencia de Valparaíso, Universidad de Valparaíso, Valparaíso, Chile
- Millennium Nucleus in NanoBioPhysics, Universidad de Valparaíso, Valparaíso, Chile
| | - Christian Carrillo
- Centro Interdisciplinario de Neurociencia de Valparaíso, Universidad de Valparaíso, Valparaíso, Chile
- Millennium Nucleus in NanoBioPhysics, Universidad de Valparaíso, Valparaíso, Chile
| | - Miguel Fernandez
- Centro Interdisciplinario de Neurociencia de Valparaíso, Universidad de Valparaíso, Valparaíso, Chile
- Millennium Nucleus in NanoBioPhysics, Universidad de Valparaíso, Valparaíso, Chile
| | - Tania Gonzalez
- National Center for Minimally Invasive Surgery, La Habana, Cuba
| | - Jose A. Garate
- Millennium Nucleus in NanoBioPhysics, Universidad de Valparaíso, Valparaíso, Chile
- Facultad de Ingeniería y Tecnología, Universidad San Sebastián, Santiago, Chile
- Centro Científico y Tecnológico de Excelencia Ciencia y Vida, Santiago, Chile
| | - Carlos Gonzalez
- Centro Interdisciplinario de Neurociencia de Valparaíso, Universidad de Valparaíso, Valparaíso, Chile
- Millennium Nucleus in NanoBioPhysics, Universidad de Valparaíso, Valparaíso, Chile
- Department of Physiology and Biophysics, Miller School of Medicine, University of Miami, Miami, FL, United States
- *Correspondence: Carlos Gonzalez,
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19
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Numaga-Tomita T, Shimauchi T, Kato Y, Nishiyama K, Nishimura A, Sakata K, Inada H, Kita S, Iwamoto T, Nabekura J, Birnbaumer L, Mori Y, Nishida M. Inhibition of transient receptor potential cation channel 6 promotes capillary arterialization during post-ischaemic blood flow recovery. Br J Pharmacol 2023; 180:94-110. [PMID: 36068079 PMCID: PMC10092707 DOI: 10.1111/bph.15942] [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] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2021] [Revised: 08/29/2022] [Accepted: 08/31/2022] [Indexed: 12/14/2022] Open
Abstract
BACKGROUND AND PURPOSE Capillary arterialization, characterized by the coverage of pre-existing or nascent capillary vessels with vascular smooth muscle cells (VSMCs), is critical for the development of collateral arterioles to improve post-ischaemic blood flow. We previously demonstrated that the inhibition of transient receptor potential 6 subfamily C, member 6 (TRPC6) channels facilitate contractile differentiation of VSMCs under ischaemic stress. We here investigated whether TRPC6 inhibition promotes post-ischaemic blood flow recovery through capillary arterialization in vivo. EXPERIMENTAL APPROACH Mice were subjected to hindlimb ischaemia by ligating left femoral artery. The recovery rate of peripheral blood flow was calculated by the ratio of ischaemic left leg to non-ischaemic right one. The number and diameter of blood vessels were analysed by immunohistochemistry. Expression and phosphorylation levels of TRPC6 proteins were determined by western blotting and immunohistochemistry. KEY RESULTS Although the post-ischaemic blood flow recovery is reportedly dependent on endothelium-dependent relaxing factors, systemic TRPC6 deletion significantly promoted blood flow recovery under the condition that nitric oxide or prostacyclin production were inhibited, accompanying capillary arterialization. Cilostazol, a clinically approved drug for peripheral arterial disease, facilitates blood flow recovery by inactivating TRPC6 via phosphorylation at Thr69 in VSMCs. Furthermore, inhibition of TRPC6 channel activity by pyrazole-2 (Pyr2; BTP2; YM-58483) promoted post-ischaemic blood flow recovery in Apolipoprotein E-knockout mice. CONCLUSION AND IMPLICATIONS Suppression of TRPC6 channel activity in VSMCs could be a new strategy for the improvement of post-ischaemic peripheral blood circulation.
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Affiliation(s)
- Takuro Numaga-Tomita
- National Institute for Physiological Sciences (NIPS), National Institutes of Natural Sciences, Aichi, Japan.,Exploratory Research Center on Life and Living Systems (ExCELLS), National Institutes of Natural Sciences, Aichi, Japan.,SOKENDAI (School of Life Science, The Graduate University for Advanced Studies), Aichi, Japan.,Shinshu University School of Medicine, Nagano, Japan
| | - Tsukasa Shimauchi
- National Institute for Physiological Sciences (NIPS), National Institutes of Natural Sciences, Aichi, Japan.,Exploratory Research Center on Life and Living Systems (ExCELLS), National Institutes of Natural Sciences, Aichi, Japan.,Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka, Japan.,Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Yuri Kato
- Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka, Japan
| | - Kazuhiro Nishiyama
- Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka, Japan
| | - Akiyuki Nishimura
- National Institute for Physiological Sciences (NIPS), National Institutes of Natural Sciences, Aichi, Japan.,Exploratory Research Center on Life and Living Systems (ExCELLS), National Institutes of Natural Sciences, Aichi, Japan.,SOKENDAI (School of Life Science, The Graduate University for Advanced Studies), Aichi, Japan
| | - Kosuke Sakata
- Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka, Japan
| | - Hiroyuki Inada
- National Institute for Physiological Sciences (NIPS), National Institutes of Natural Sciences, Aichi, Japan
| | - Satomi Kita
- Faculty of Medicine, Fukuoka University, Fukuoka, Japan.,Faculty of Pharmaceutical Sciences, Tokushima Bunri University, Tokushima, Japan
| | | | - Junichi Nabekura
- National Institute for Physiological Sciences (NIPS), National Institutes of Natural Sciences, Aichi, Japan
| | - Lutz Birnbaumer
- NIEHS, NIH, Research Triangle Park, North Carolina, USA.,Institute for Biomedical Research (BIOMED), Catholic University of Argentina, Buenos Aires, Argentina
| | - Yasuo Mori
- Graduate School of Engineering, Kyoto University, Kyoto, Japan
| | - Motohiro Nishida
- National Institute for Physiological Sciences (NIPS), National Institutes of Natural Sciences, Aichi, Japan.,Exploratory Research Center on Life and Living Systems (ExCELLS), National Institutes of Natural Sciences, Aichi, Japan.,SOKENDAI (School of Life Science, The Graduate University for Advanced Studies), Aichi, Japan.,Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka, Japan
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20
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Tong Y, Ma X, Hu T, Chen K, Cui G, Su P, Xu H, Gao W, Jiang T, Huang L. Structural and mechanistic insights into the precise product synthesis by a bifunctional miltiradiene synthase. Plant Biotechnol J 2023; 21:165-175. [PMID: 36161753 PMCID: PMC9829396 DOI: 10.1111/pbi.13933] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/15/2022] [Revised: 07/22/2022] [Accepted: 09/14/2022] [Indexed: 06/16/2023]
Abstract
Selaginella moellendorffii miltiradiene synthase (SmMDS) is a unique bifunctional diterpene synthase (diTPS) that catalyses the successive cyclization of (E,E,E)-geranylgeranyl diphosphate (GGPP) via (+)-copalyl diphosphate (CPP) to miltiradiene, which is a crucial precursor of important medicinal compounds, such as triptolide, ecabet sodium and carnosol. Miltiradiene synthetic processes have been studied in monofunctional diTPSs, while the precise mechanism by which active site amino acids determine product simplicity and the experimental evidence for reaction intermediates remain elusive. In addition, how bifunctional diTPSs work compared to monofunctional enzymes is attractive for detailed research. Here, by mutagenesis studies of SmMDS, we confirmed that pimar-15-en-8-yl+ is an intermediate in miltiradiene synthesis. Moreover, we determined the apo-state and the GGPP-bound state crystal structures of SmMDS. By structure analysis and mutagenesis experiments, possible contributions of key residues both in class I and II active sites were suggested. Based on the structural and functional analyses, we confirmed the copal-15-yl+ intermediate and unveiled more details of the catalysis process in the SmMDS class I active site. Moreover, the structural and experimental results suggest an internal channel for (+)-CPP produced in the class II active site moving towards the class I active site. Our research is a good example for intermediate identification of diTPSs and provides new insights into the product specificity determinants and intermediate transport, which should greatly facilitate the precise controlled synthesis of various diterpenes.
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Affiliation(s)
- Yuru Tong
- National Resource Center for Chinese Materia MedicaChina Academy of Chinese Medical SciencesBeijingChina
- School of Pharmaceutical SciencesCapital Medical UniversityBeijingChina
| | - Xiaoli Ma
- National Laboratory of BiomacromoleculesInstitute of Biophysics, Chinese Academy of SciencesBeijingChina
| | - Tianyuan Hu
- School of Pharmaceutical SciencesCapital Medical UniversityBeijingChina
| | - Kang Chen
- National Resource Center for Chinese Materia MedicaChina Academy of Chinese Medical SciencesBeijingChina
| | - Guanghong Cui
- National Resource Center for Chinese Materia MedicaChina Academy of Chinese Medical SciencesBeijingChina
| | - Ping Su
- National Resource Center for Chinese Materia MedicaChina Academy of Chinese Medical SciencesBeijingChina
| | - Haifeng Xu
- National Laboratory of BiomacromoleculesInstitute of Biophysics, Chinese Academy of SciencesBeijingChina
- University of Chinese Academy of SciencesBeijingChina
| | - Wei Gao
- Beijing Shijitan HospitalCapital Medical UniversityBeijingChina
| | - Tao Jiang
- National Laboratory of BiomacromoleculesInstitute of Biophysics, Chinese Academy of SciencesBeijingChina
- University of Chinese Academy of SciencesBeijingChina
| | - Luqi Huang
- National Resource Center for Chinese Materia MedicaChina Academy of Chinese Medical SciencesBeijingChina
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21
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Liao QQ, Dong QQ, Zhang H, Shu HP, Tu YC, Yao LJ. Contributions of SGK3 to transporter-related diseases. Front Cell Dev Biol 2022; 10:1007924. [PMID: 36531961 PMCID: PMC9753149 DOI: 10.3389/fcell.2022.1007924] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2022] [Accepted: 11/09/2022] [Indexed: 02/09/2024] Open
Abstract
Serum- and glucocorticoid-induced kinase 3 (SGK3), which is ubiquitously expressed in mammals, is regulated by estrogens and androgens. SGK3 is activated by insulin and growth factors through signaling pathways involving phosphatidylinositol-3-kinase (PI3K), 3-phosphoinositide-dependent kinase-1 (PDK-1), and mammalian target of rapamycin complex 2 (mTORC2). Activated SGK3 can activate ion channels (TRPV5/6, SOC, Kv1.3, Kv1.5, Kv7.1, BKCa, Kir2.1, Kir2.2, ENaC, Nav1.5, ClC-2, and ClC Ka), carriers and receptors (Npt2a, Npt2b, NHE3, GluR1, GluR6, SN1, EAAT1, EAAT2, EAAT4, EAAT5, SGLT1, SLC1A5, SLC6A19, SLC6A8, and NaDC1), and Na+/K+-ATPase, promoting the transportation of calcium, phosphorus, sodium, glucose, and neutral amino acids in the kidney and intestine, the absorption of potassium and neutral amino acids in the renal tubules, the transportation of glutamate and glutamine in the nervous system, and the transportation of creatine. SGK3-sensitive transporters contribute to a variety of physiological and pathophysiological processes, such as maintaining calcium and phosphorus homeostasis, hydro-salinity balance and acid-base balance, cell proliferation, muscle action potential, cardiac and neural electrophysiological disturbances, bone density, intestinal nutrition absorption, immune function, and multiple substance metabolism. These processes are related to kidney stones, hypophosphorous rickets, multiple syndromes, arrhythmia, hypertension, heart failure, epilepsy, Alzheimer's disease, amyotrophic lateral sclerosis, glaucoma, ataxia idiopathic deafness, and other diseases.
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Affiliation(s)
- Qian-Qian Liao
- Department of Nephrology, Tongji Medical College, Union Hospital, Huazhong University of Science and Technology, Wuhan, China
| | - Qing-Qing Dong
- Department of Nephrology, Tongji Medical College, Union Hospital, Huazhong University of Science and Technology, Wuhan, China
- Department of Nephrology, The Second Affiliated Hospital, Chongqing Medical University, Chongqing, China
| | - Hui Zhang
- Department of Nephrology, Tongji Medical College, Union Hospital, Huazhong University of Science and Technology, Wuhan, China
| | - Hua-Pan Shu
- Department of Nephrology, Tongji Medical College, Union Hospital, Huazhong University of Science and Technology, Wuhan, China
| | - Yu-Chi Tu
- Department of Nephrology, Tongji Medical College, Union Hospital, Huazhong University of Science and Technology, Wuhan, China
| | - Li-Jun Yao
- Department of Nephrology, Tongji Medical College, Union Hospital, Huazhong University of Science and Technology, Wuhan, China
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22
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Yedurkar DP, Metkar SP, Al-Turjman F, Stephan T, Kolhar M, Altrjman C. A Novel Approach for Multi channel Epileptic Seizure Classification Based on Internet of Things Framework Using Critical Spectral Verge Feature Derived from Flower Pollination Algorithm. Sensors (Basel) 2022; 22:9302. [PMID: 36502005 PMCID: PMC9737714 DOI: 10.3390/s22239302] [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] [Figures] [Subscribe] [Scholar Register] [Received: 09/30/2022] [Revised: 11/07/2022] [Accepted: 11/11/2022] [Indexed: 06/17/2023]
Abstract
A novel approach for multichannel epilepsy seizure classification which will help to automatically locate seizure activity present in the focal brain region was proposed. This paper suggested an Internet of Things (IoT) framework based on a smart phone by utilizing a novel feature termed multiresolution critical spectral verge (MCSV), based on frequency-derived information for epileptic seizure classification which was optimized using a flower pollination algorithm (FPA). A wireless sensor technology (WSN) was utilized to record the electroencephalography (EEG) signal of epileptic patients. Next, the EEG signal was pre-processed utilizing a multiresolution-based adaptive filtering (MRAF) method. Then, the maximal frequency point at which the power spectral density (PSD) of each EEG segment was greater than the average spectral power of the corresponding frequency band was computed. This point was further optimized to extract a point termed as critical spectral verge (CSV) to extract the exact high frequency oscillations representing the actual seizure activity present in the EEG signal. Next, a support vector machine (SVM) classifier was used for channel-wise classification of the seizure and non-seizure regions using CSV as a feature. This process of classification using the CSV feature extracted from the MRAF output is referred to as the MCSV approach. As a final step, cloud-based services were employed to analyze the EEG information from the subject's smart phone. An exhaustive analysis was undertaken to assess the performance of the MCSV approach for two datasets. The presented approach showed an improved performance with a 93.83% average sensitivity, a 97.94% average specificity, a 97.38% average accuracy with the SVM classifier, and a 95.89% average detection rate as compared with other state-of-the-art studies such as deep learning. The methods presented in the literature were unable to precisely localize the origination of the seizure activity in the brain region and reported a low seizure detection rate. This work introduced an optimized CSV feature which was effectively used for multichannel seizure classification and localization of seizure origination. The proposed MCSV approach will help diagnose epileptic behavior from multichannel EEG signals which will be extremely useful for neuro-experts to analyze seizure details from different regions of the brain.
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Affiliation(s)
| | - Shilpa P. Metkar
- Department of Electronics and Telecommunication Engineering, College of Engineering Pune, Pune 411005, India
| | - Fadi Al-Turjman
- Artificial Intelligence Engineering Department, AI and Robotics Institute, Near East University, Mersin 10, Turkey
- Research Center for AI and IoT, Faculty of Engineering, University of Kyrenia, Mersin 10, Turkey
| | - Thompson Stephan
- Department of Computer Science and Engineering, Faculty of Engineering and Technology, M. S. Ramaiah University of Applied Sciences, Bangalore 560054, India
| | - Manjur Kolhar
- Department of Computer Science, College of Arts and Science, Prince Sattam Bin Abdulaziz University, Al-Kharj 16278, Saudi Arabia
| | - Chadi Altrjman
- Research Center for AI and IoT, Faculty of Engineering, University of Kyrenia, Mersin 10, Turkey
- Faculty of Engineering, University of Waterloo, Waterloo, ON N2L 3G1, Canada
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23
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Ali Z, Qureshi KN, Mustafa K, Bukhsh R, Aslam S, Mujlid H, Ghafoor KZ. Edge Based Priority-Aware Dynamic Resource Allocation for Internet of Things Networks. Entropy (Basel) 2022; 24:1607. [PMID: 36359697 PMCID: PMC9689225 DOI: 10.3390/e24111607] [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] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/21/2022] [Revised: 10/19/2022] [Accepted: 10/28/2022] [Indexed: 06/16/2023]
Abstract
The exponential growth of the edge-based Internet-of-Things (IoT) services and its ecosystems has recently led to a new type of communication network, the Low Power Wide Area Network (LPWAN). This standard enables low-power, long-range, and low-data-rate communications. Long Range Wide Area Network (LoRaWAN) is a recent standard of LPWAN that incorporates LoRa wireless into a networked infrastructure. Consequently, the consumption of smart End Devices (EDs) is a major challenge due to the highly dense network environment characterised by limited battery life, spectrum coverage, and data collisions. Intelligent and efficient service provisioning is an urgent need of a network to streamline the networks and solve these problems. This paper proposes a Dynamic Reinforcement Learning Resource Allocation (DRLRA) approach to allocate efficient resources such as channel, Spreading Factor (SF), and Transmit Power (Tp) to EDs that ultimately improve the performance in terms of consumption and reliability. The proposed model is extensively simulated and evaluated with the currently implemented algorithms such as Adaptive Data Rate (ADR) and Adaptive Priority-aware Resource Allocation (APRA) using standard and advanced evaluation metrics. The proposed work is properly cross validated to show completely unbiased results.
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Affiliation(s)
- Zulfiqar Ali
- Department of Software Engineering, Bahria University, Islamabad 46000, Pakistan
| | | | - Kainat Mustafa
- Department of Computer Science, Virtual University of Pakistan, Lahore 54000, Pakistan
| | - Rasool Bukhsh
- Department of Computer Science, COMSATS University Islamabad, Islamabad 44000, Pakistan
| | - Sheraz Aslam
- Department of Electrical Engineering, Computer Engineering, and Informatics, Cyprus University of Technology, 3036 Limassol, Cyprus
| | - Hana Mujlid
- Department of Computer Engineering, Taif University, Taif 21944, Saudi Arabia
| | - Kayhan Zrar Ghafoor
- Department of Computer Science, Knowledge University, University Park, Kirkuk Road, Erbil 446015, Iraq
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24
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Abstract
Silicon is a beneficial element for plant growth and production, especially in rice. Plant roots take up silicon in the form of silicic acid. Silicic acid channels, which belong to the NIP subfamily of aquaporins, are responsible for silicic acid uptake. Accumulated experimental results have deepened our understanding of the silicic acid channel for its uptake mechanism, physiological function, localization, and other aspects. However, how the silicic acid channel efficiently and selectively permeates silicic acid remains to be elucidated. Recently reported crystal structures of the silicic acid channel enabled us to discuss the mechanism of silicic acid uptake by plant roots at an atomic level. In this mini-review, we focus on the crystal structures of the silicic acid channel and provide a detailed description of the structural determinants of silicic acid permeation and its transport mechanism, which are crucial for the rational creation of secure and sustainable crops.
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Affiliation(s)
- Yasunori Saitoh
- Research Institute for Interdisciplinary Science, Okayama University, Okayama, Japan
| | - Michihiro Suga
- Research Institute for Interdisciplinary Science, Okayama University, Okayama, Japan
- Graduate School of Natural Science and Technology, Okayama University, Okayama, Japan
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25
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Rendulić T, Mendonça Bahia F, Soares-Silva I, Nevoigt E, Casal M. The Dicarboxylate Transporters from the AceTr Family and Dct-02 Oppositely Affect Succinic Acid Production in S. cerevisiae. J Fungi (Basel) 2022; 8:822. [PMID: 36012810 DOI: 10.3390/jof8080822] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2022] [Revised: 07/28/2022] [Accepted: 08/04/2022] [Indexed: 11/17/2022] Open
Abstract
Membrane transporters are important targets in metabolic engineering to establish and improve the production of chemicals such as succinic acid from renewable resources by microbial cell factories. We recently provided a Saccharomyces cerevisiae strain able to strongly overproduce succinic acid from glycerol and CO2 in which the Dct-02 transporter from Aspergillus niger, assumed to be an anion channel, was used to export succinic acid from the cells. In a different study, we reported a new group of succinic acid transporters from the AceTr family, which were also described as anion channels. Here, we expressed these transporters in a succinic acid overproducing strain and compared their impact on extracellular succinic acid accumulation with that of the Dct-02 transporter. The results show that the tested transporters of the AceTr family hinder succinic acid accumulation in the extracellular medium at low pH, which is in strong contrast to Dct-02. Data suggests that the AceTr transporters prefer monovalent succinate, whereas Dct-02 prefers divalent succinate anions. In addition, the results provided deeper insights into the characteristics of Dct-02, showing its ability to act as a succinic acid importer (thus being bidirectional) and verifying its capability of exporting malate.
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26
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Chen L, Peng G, Comollo TW, Zou X, Sampson KJ, Larsson HP, Kass RS. Two small-molecule activators share similar effector sites in the KCNQ1 channel pore but have distinct effects on voltage sensor movements. Front Physiol 2022; 13:903050. [PMID: 35957984 PMCID: PMC9359618 DOI: 10.3389/fphys.2022.903050] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2022] [Accepted: 06/30/2022] [Indexed: 11/13/2022] Open
Abstract
ML277 and R-L3 are two small-molecule activators of KCNQ1, the pore-forming subunit of the slowly activating potassium channel IKs. KCNQ1 loss-of-function mutations prolong cardiac action potential duration and are associated with long QT syndrome, which predispose patients to lethal ventricular arrhythmia. ML277 and R-L3 enhance KCNQ1 current amplitude and slow deactivation. However, the presence of KCNE1, an auxiliary subunit of IKs channels, renders the channel insensitive to both activators. We found that ML277 effects are dependent on several residues in the KCNQ1 pore domain. Some of these residues are also necessary for R-L3 effects. These residues form a putative hydrophobic pocket located between two adjacent KCNQ1 subunits, where KCNE1 subunits are thought to dwell, thus providing an explanation for how KCNE1 renders the IKs channel insensitive to these activators. Our experiments showed that the effect of R-L3 on voltage sensor movement during channel deactivation was much more prominent than that of ML277. Simulations using a KCNQ1 kinetic model showed that the effects of ML277 and R-L3 could be reproduced through two different effects on channel gating: ML277 enhances KCNQ1 channel function through a pore-dependent and voltage sensor-independent mechanism, while R-L3 affects both channel pore and voltage sensor.
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Affiliation(s)
- Lei Chen
- Department of Molecular Pharmacology and Therapeutics, Vagelos College of Physicians & Surgeons of Columbia University Irving Medical Center, New York, NY, United States
| | - Gary Peng
- Department of Molecular Pharmacology and Therapeutics, Vagelos College of Physicians & Surgeons of Columbia University Irving Medical Center, New York, NY, United States
| | - Thomas W. Comollo
- Department of Molecular Pharmacology and Therapeutics, Vagelos College of Physicians & Surgeons of Columbia University Irving Medical Center, New York, NY, United States
| | - Xinle Zou
- Department of Molecular Pharmacology and Therapeutics, Vagelos College of Physicians & Surgeons of Columbia University Irving Medical Center, New York, NY, United States
| | - Kevin J. Sampson
- Department of Molecular Pharmacology and Therapeutics, Vagelos College of Physicians & Surgeons of Columbia University Irving Medical Center, New York, NY, United States
| | - H. Peter Larsson
- Department of Physiology and Biophysics, Miller School of Medicine, University of Miami, Miami, FL, United States
| | - Robert S. Kass
- Department of Molecular Pharmacology and Therapeutics, Vagelos College of Physicians & Surgeons of Columbia University Irving Medical Center, New York, NY, United States,*Correspondence: Robert S. Kass,
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27
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Li X, Zhang J, Shi H, Li B, Li J. Rapid responses: Receptor-like kinases directly regulate the functions of membrane transport proteins in plants. J Integr Plant Biol 2022; 64:1303-1309. [PMID: 35546272 DOI: 10.1111/jipb.13274] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [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: 03/21/2022] [Accepted: 05/09/2022] [Indexed: 06/15/2023]
Abstract
Receptor-like kinases (RLKs) are a large group of plant-specific transmembrane proteins mainly acting as receptors or co-receptors of various extracellular signals. They usually turn extracellular signals into intracellular responses via altering gene expression profiles. However, recent studies confirmed that many RLKs can physically interact with diverse membrane-localized transport proteins and regulate their activities for speedy responses in limited tissues or cells. In this minireview, we highlight recent discoveries regarding how RLKs can work with membrane transport proteins collaboratively and thereby trigger cellular responses in a precise and rapid manner. It is anticipated that such regulation broadly presents in plants and more examples will be gradually revealed when in-depth analyses are conducted for the functions of RLKs.
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Affiliation(s)
- Xiaopeng Li
- Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou, 730000, China
| | - Jingjie Zhang
- Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou, 730000, China
| | - Hongyong Shi
- Guangdong Provincial Key Laboratory of Plant Adaptation and Molecular Design, School of Life Sciences, Guangzhou University, Guangzhou, 510006, China
| | - Bo Li
- Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou, 730000, China
| | - Jia Li
- Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou, 730000, China
- Guangdong Provincial Key Laboratory of Plant Adaptation and Molecular Design, School of Life Sciences, Guangzhou University, Guangzhou, 510006, China
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28
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Mehinovic E, Gray T, Campbell M, Ekholm J, Wenger A, Rowell W, Grudo A, Grimwood J, Korlach J, Gurnett C, Constantino JN, Turner TN. Germline mosaicism of a missense variant in KCNC2 in a multiplex family with autism and epilepsy characterized by long-read sequencing. Am J Med Genet A 2022; 188:2071-2081. [PMID: 35366058 PMCID: PMC9197999 DOI: 10.1002/ajmg.a.62743] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2021] [Revised: 02/04/2022] [Accepted: 02/18/2022] [Indexed: 02/06/2023]
Abstract
Currently, protein-coding de novo variants and large copy number variants have been identified as important for ~30% of individuals with autism. One approach to identify relevant variation in individuals who lack these types of events is by utilizing newer genomic technologies. In this study, highly accurate PacBio HiFi long-read sequencing was applied to a family with autism, epileptic encephalopathy, cognitive impairment, and mild dysmorphic features (two affected female siblings, unaffected parents, and one unaffected male sibling) with no known clinical variant. From our long-read sequencing data, a de novo missense variant in the KCNC2 gene (encodes Kv3.2) was identified in both affected children. This variant was phased to the paternal chromosome of origin and is likely a germline mosaic. In silico assessment revealed the variant was not in controls, highly conserved, and predicted damaging. This specific missense variant (Val473Ala) has been shown in both an ortholog and paralog of Kv3.2 to accelerate current decay, shift the voltage dependence of activation, and prevent the channel from entering a long-lasting open state. Seven additional missense variants have been identified in other individuals with neurodevelopmental disorders (p = 1.03 × 10-5 ). KCNC2 is most highly expressed in the brain; in particular, in the thalamus and is enriched in GABAergic neurons. Long-read sequencing was useful in discovering the relevant variant in this family with autism that had remained a mystery for several years and will potentially have great benefits in the clinic once it is widely available.
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Affiliation(s)
- Elvisa Mehinovic
- Department of GeneticsWashington University School of MedicineSt. LouisMissouriUSA
| | - Teddi Gray
- Department of PsychiatryWashington University School of MedicineSt. LouisMissouriUSA
| | - Meghan Campbell
- Department of PsychiatryWashington University School of MedicineSt. LouisMissouriUSA
| | | | | | | | - Ari Grudo
- Pacific BiosciencesMenlo ParkCaliforniaUSA
| | - Jane Grimwood
- HudsonAlpha Institute for BiotechnologyHuntsvilleAlabamaUSA
| | | | - Christina Gurnett
- Department of NeurologyWashington University School of MedicineSt. LouisMissouriUSA
| | - John N. Constantino
- Department of PsychiatryWashington University School of MedicineSt. LouisMissouriUSA
| | - Tychele N. Turner
- Department of GeneticsWashington University School of MedicineSt. LouisMissouriUSA
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29
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Hempel C, Rosenthal R, Fromm A, Krug SM, Fromm M, Günzel D, Piontek J. Tight junction channels claudin-10b and claudin-15: Functional mapping of pore-lining residues. Ann N Y Acad Sci 2022; 1515:129-142. [PMID: 35650657 DOI: 10.1111/nyas.14794] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Although functional and structural models for paracellular channels formed by claudins have been reported, mechanisms regulating charge and size selectivity of these channels are unknown in detail. Here, claudin-15 and claudin-10b cation channels showing high-sequence similarity but differing channel properties were analyzed. Mutants of pore-lining residues were expressed in MDCK-C7 cells. In claudin-15, proposed ion interaction sites (D55 and E64) conserved between both claudins were neutralized. D55N and E64Q substitutions decreased ion permeabilities, and D55N/E64Q had partly additive effects. D55N increased cation dehydration capability and decreased pore diameter. Additionally, residues differing between claudin-15 and -10b close to pore center were analyzed. Claudin-10b-mimicking W63K affected neither assembly nor function of claudin-15 channels. In contrast, in claudin-10b, corresponding (claudin-15b-mimicking) K64W and K64M substitutions disturbed integration into tight junction and slightly altered relative permeabilities for differently sized monovalent cations. Removal of claudin-10b-specific negative charge (D36A substitution) was without effect. The data suggest that a common tetra-aspartate ring (D55/D56) in pore center of claudin-15/-10b channels directly attracts cations, while E64/D65 may be at least partly shielded by W63/K64. Charge at position W63/K64 affects assembly and properties for claudin-10b but not for claudin-15 channels. Our findings add to the mechanistic understanding of the determinants of paracellular cation permeability.
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Affiliation(s)
- Caroline Hempel
- Clinical Physiology/Nutritional Medicine, Medizinische Klinik für Gastroenterologie, Infektiologie und Rheumatologie, Charité - Universitätsmedizin Berlin, Berlin, Germany
| | - Rita Rosenthal
- Clinical Physiology/Nutritional Medicine, Medizinische Klinik für Gastroenterologie, Infektiologie und Rheumatologie, Charité - Universitätsmedizin Berlin, Berlin, Germany
| | - Anja Fromm
- Clinical Physiology/Nutritional Medicine, Medizinische Klinik für Gastroenterologie, Infektiologie und Rheumatologie, Charité - Universitätsmedizin Berlin, Berlin, Germany
| | - Susanne M Krug
- Clinical Physiology/Nutritional Medicine, Medizinische Klinik für Gastroenterologie, Infektiologie und Rheumatologie, Charité - Universitätsmedizin Berlin, Berlin, Germany
| | - Michael Fromm
- Clinical Physiology/Nutritional Medicine, Medizinische Klinik für Gastroenterologie, Infektiologie und Rheumatologie, Charité - Universitätsmedizin Berlin, Berlin, Germany
| | - Dorothee Günzel
- Clinical Physiology/Nutritional Medicine, Medizinische Klinik für Gastroenterologie, Infektiologie und Rheumatologie, Charité - Universitätsmedizin Berlin, Berlin, Germany
| | - Jörg Piontek
- Clinical Physiology/Nutritional Medicine, Medizinische Klinik für Gastroenterologie, Infektiologie und Rheumatologie, Charité - Universitätsmedizin Berlin, Berlin, Germany
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30
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Abstract
Calcium ions function as a key second messenger ion in eukaryotes. Spatially and temporally defined cytoplasmic Ca2+ signals are shaped through the concerted activity of ion channels, exchangers, and pumps in response to diverse stimuli; these signals are then decoded through the activity of Ca2+ -binding sensor proteins. In plants, Ca2+ signaling is central to both pattern- and effector-triggered immunity, with the generation of characteristic cytoplasmic Ca2+ elevations in response to potential pathogens being common to both. However, despite their importance, and a long history of scientific interest, the transport proteins that shape Ca2+ signals and their integration remain poorly characterized. Here, we discuss recent work that has both shed light on and deepened the mysteries of Ca2+ signaling in plant immunity.
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Affiliation(s)
- Philipp Köster
- Institute of Plant and Microbial Biology and Zürich-Basel Plant Science Center, University of Zürich, Zürich, Switzerland
| | - Thomas A DeFalco
- Institute of Plant and Microbial Biology and Zürich-Basel Plant Science Center, University of Zürich, Zürich, Switzerland
| | - Cyril Zipfel
- Institute of Plant and Microbial Biology and Zürich-Basel Plant Science Center, University of Zürich, Zürich, Switzerland.,The Sainsbury Laboratory, University of East Anglia, Norwich, UK
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31
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Wu DP, Bai LR, Lv YF, Zhou Y, Ding CH, Yang SM, Zhang F, Wang YY, Huang JL, Yin XX. Corrigendum: A Novel Role of Connexin 40-Formed Channels in the Enhanced Efficacy of Photodynamic Therapy. Front Oncol 2022; 12:853278. [PMID: 35280752 PMCID: PMC8906186 DOI: 10.3389/fonc.2022.853278] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2022] [Accepted: 01/19/2022] [Indexed: 11/16/2022] Open
Affiliation(s)
- Deng-Pan Wu
- Jiangsu Key Laboratory of New Drug Research and Clinical Pharmacy, Pharmacy School of Xuzhou Medical University, Xuzhou, China.,Department of Pharmacology, Pharmacy School of Xuzhou Medical University, Xuzhou, China
| | - Li-Ru Bai
- Department of Pharmacy, Wuxi Ninth Affiliated Hospital of Suzhou University, Wuxi, China
| | - Yan-Fang Lv
- Jiangsu Key Laboratory of New Drug Research and Clinical Pharmacy, Pharmacy School of Xuzhou Medical University, Xuzhou, China
| | - Yan Zhou
- Jiangsu Key Laboratory of New Drug Research and Clinical Pharmacy, Pharmacy School of Xuzhou Medical University, Xuzhou, China
| | - Chun-Hui Ding
- Jiangsu Key Laboratory of New Drug Research and Clinical Pharmacy, Pharmacy School of Xuzhou Medical University, Xuzhou, China
| | - Si-Man Yang
- Scientific Research Center of Traditional Chinese Medicine, Guangxi University of Chinese Medicine, Nanning, China
| | - Fan Zhang
- Scientific Research Center of Traditional Chinese Medicine, Guangxi University of Chinese Medicine, Nanning, China
| | - Yuan-Yuan Wang
- Jiangsu Key Laboratory of New Drug Research and Clinical Pharmacy, Pharmacy School of Xuzhou Medical University, Xuzhou, China
| | - Jin-Lan Huang
- Jiangsu Key Laboratory of New Drug Research and Clinical Pharmacy, Pharmacy School of Xuzhou Medical University, Xuzhou, China.,Department of Pharmacology, Pharmacy School of Xuzhou Medical University, Xuzhou, China
| | - Xiao-Xing Yin
- Jiangsu Key Laboratory of New Drug Research and Clinical Pharmacy, Pharmacy School of Xuzhou Medical University, Xuzhou, China
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32
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Chen X, Wang Y, Li Y, Lu X, Chen J, Li M, Wen T, Liu N, Chang S, Zhang X, Yang X, Shen Y. Cryo-EM structure of the human TACAN in a closed state. Cell Rep 2022; 38:110445. [PMID: 35235791 DOI: 10.1016/j.celrep.2022.110445] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2021] [Revised: 12/17/2021] [Accepted: 02/04/2022] [Indexed: 12/22/2022] Open
Abstract
TACAN is an ion channel-like protein that may be involved in sensing mechanical pain. Here, we present the cryo-electron microscopic structure of human TACAN (hTACAN). hTACAN forms a dimer in which each protomer consists of a transmembrane globular domain (TMD) containing six helices and an intracellular domain (ICD) containing two helices. Molecular dynamic simulations suggest that each protomer contains a putative ion conduction pore. A single-point mutation of the key residue Met207 greatly increases membrane pressure-activated currents. In addition, each hTACAN subunit binds one cholesterol molecule. Our data show the molecular assembly of hTACAN and suggest that wild-type hTACAN is in a closed state.
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Affiliation(s)
- Xiaozhe Chen
- State Key Laboratory of Medicinal Chemical Biology and College of Life Sciences, Nankai University, Tianjin 300350, China; Frontiers Science Center for Cell Responses, Nankai University, Tianjin 300350, China
| | - Yaojie Wang
- State Key Laboratory of Medicinal Chemical Biology and College of Life Sciences, Nankai University, Tianjin 300350, China; Frontiers Science Center for Cell Responses, Nankai University, Tianjin 300350, China
| | - Yang Li
- State Key Laboratory of Medicinal Chemical Biology and College of Life Sciences, Nankai University, Tianjin 300350, China; Frontiers Science Center for Cell Responses, Nankai University, Tianjin 300350, China
| | - Xuhang Lu
- State Key Laboratory of Medicinal Chemical Biology and College of Life Sciences, Nankai University, Tianjin 300350, China; Frontiers Science Center for Cell Responses, Nankai University, Tianjin 300350, China
| | - Jianan Chen
- State Key Laboratory of Medicinal Chemical Biology and College of Life Sciences, Nankai University, Tianjin 300350, China; College of Pharmacy, Nankai University, Tianjin 300350, China
| | - Ming Li
- State Key Laboratory of Medicinal Chemical Biology and College of Life Sciences, Nankai University, Tianjin 300350, China; Frontiers Science Center for Cell Responses, Nankai University, Tianjin 300350, China
| | - Tianlei Wen
- State Key Laboratory of Medicinal Chemical Biology and College of Life Sciences, Nankai University, Tianjin 300350, China; Frontiers Science Center for Cell Responses, Nankai University, Tianjin 300350, China
| | - Ning Liu
- State Key Laboratory of Medicinal Chemical Biology and College of Life Sciences, Nankai University, Tianjin 300350, China
| | - Shenghai Chang
- Department of Biophysics and Department of Pathology of Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou 310027, China; Center of Cryo Electron Microscopy, Zhejiang University School of Medicine, Hangzhou 310027, China
| | - Xing Zhang
- Department of Biophysics and Department of Pathology of Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou 310027, China; Center of Cryo Electron Microscopy, Zhejiang University School of Medicine, Hangzhou 310027, China
| | - Xue Yang
- State Key Laboratory of Medicinal Chemical Biology and College of Life Sciences, Nankai University, Tianjin 300350, China; Frontiers Science Center for Cell Responses, Nankai University, Tianjin 300350, China.
| | - Yuequan Shen
- State Key Laboratory of Medicinal Chemical Biology and College of Life Sciences, Nankai University, Tianjin 300350, China; Frontiers Science Center for Cell Responses, Nankai University, Tianjin 300350, China; Synergetic Innovation Center of Chemical Science and Engineering, Tianjin 300071, China.
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Klaus M, Labasque T, Botter G, Durighetto N, Schelker J. Unraveling the Contribution of Turbulence and Bubbles to Air-Water Gas Exchange in Running Waters. J Geophys Res Biogeosci 2022; 127:e2021JG006520. [PMID: 35860336 PMCID: PMC9285787 DOI: 10.1029/2021jg006520] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/06/2021] [Revised: 12/07/2021] [Accepted: 01/26/2022] [Indexed: 06/15/2023]
Abstract
Quantifying air-water gas exchange is critical for estimating greenhouse gas fluxes and metabolism in aquatic ecosystems. In high-energy streams, the gas exchange rate k is poorly constrained, due to an incomplete understanding of turbulence and bubble contributions to k. We performed a flume experiment with air bubble additions to evaluate the combined effects of turbulence and bubbles on k for helium, argon, xenon, and methane. We created contrasting hydraulic conditions by varying channel slope, bed roughness, water discharge, and bubble flux. We found that k increased from 1-4 to 17-66 m d-1 with increases in turbulence and bubble flux metrics. Mechanistic models that explicitly account for these metrics, as well as gas diffusivity and solubility, agreed well with the data and indicated that bubble-mediated gas exchange accounted for 64-93% of k. Bubble contributions increased with bubble flux but were independent of gas type, as bubbles did not equilibrate with the water. This was evident through modeled bubble life and equilibration times inferred from bubble size distributions obtained from underwater sound spectra. Sound spectral properties correlated well with turbulence and bubble flux metrics. Our results demonstrate that (a) mechanistic models can be applied to separate free surface- and bubble-mediated gas exchange in running waters, (b) bubble life and equilibration times are critical for accurate scaling of k between different gases, and (c) ambient sound spectra can be used to approximate contributions of turbulence and bubbles.
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Affiliation(s)
- M. Klaus
- Department of Forest Ecology and ManagementSwedish University of Agricultural SciencesUmeåSweden
| | - T. Labasque
- Géosciences RennesUniversité RennesCNRSRennesFrance
| | - G. Botter
- Department of Civil Architectural and Environmental EngineeringUniversity of PadovaPadovaItaly
| | - N. Durighetto
- Department of Civil Architectural and Environmental EngineeringUniversity of PadovaPadovaItaly
| | - J. Schelker
- WasserCluster Lunz ‐ Biological StationLunz am SeeAustria
- Department of Functional and Evolutionary EcologyUniversity of ViennaViennaAustria
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Zhu Y. Gap Junction-Dependent and -Independent Functions of Connexin43 in Biology. Biology (Basel) 2022; 11:283. [PMID: 35205149 DOI: 10.3390/biology11020283] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/31/2021] [Revised: 02/08/2022] [Accepted: 02/10/2022] [Indexed: 12/21/2022]
Abstract
For the first time in animal evolution, the emergence of gap junctions allowed direct exchanges of cellular substances for communication between two cells. Innexin proteins constituted primordial gap junctions until the connexin protein emerged in deuterostomes and took over the gap junction function. After hundreds of millions of years of gene duplication, the connexin gene family now comprises 21 members in the human genome. Notably, GJA1, which encodes the Connexin43 protein, is one of the most widely expressed and commonly studied connexin genes. The loss of Gja1 in mice leads to swelling and a blockage of the right ventricular outflow tract and death of the embryos at birth, suggesting a vital role of Connexin43 gap junction in heart development. Since then, the importance of Connexin43-mediated gap junction function has been constantly expanded to other types of cells. Other than forming gap junctions, Connexin43 can also form hemichannels to release or uptake small molecules from the environment or even mediate many physiological processes in a gap junction-independent manner on plasma membranes. Surprisingly, Connexin43 also localizes to mitochondria in the cell, playing important roles in mitochondrial potassium import and respiration. At the molecular level, Connexin43 mRNA and protein are processed with very distinct mechanisms to yield carboxyl-terminal fragments with different sizes, which have their unique subcellular localization and distinct biological activities. Due to many exciting advancements in Connexin43 research, this review aims to start with a brief introduction of Connexin43 and then focuses on updating our knowledge of its gap junction-independent functions.
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Abstract
A variety of signals, including inflammasome activation, trigger the formation of large transmembrane pores by gasdermin D (GSDMD). There are primarily two functions of the GSDMD pore, to drive lytic cell death, known as pyroptosis, and to permit the release of leaderless interleukin-1 (IL-1) family cytokines, a process that does not require pyroptosis. We are interested in the mechanism by which the GSDMD pore channels IL-1 release from living cells. Recent studies revealed that electrostatic interaction, in addition to cargo size, plays a critical role in GSDMD-dependent protein release. Here, we determined computationally that to enable electrostatic filtering against pro-IL-1β, acidic lipids in the membrane need to effectively neutralize positive charges in the membrane-facing patches of the GSDMD pore. In addition, we predicted that salt has an attenuating effect on electrostatic filtering and then validated this prediction using a liposome leakage assay. A calibrated electrostatic screening factor is necessary to account for the experimental observations, suggesting that ion distribution within the pore may be different from the bulk solution. Our findings corroborate the electrostatic influence of IL-1 transport exerted by the GSDMD pore and reveal extrinsic factors, including lipid and salt, that affect the electrostatic environment.
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Charlestin V, Fulkerson D, Arias Matus CE, Walker ZT, Carthy K, Littlepage LE. Aquaporins: New players in breast cancer progression and treatment response. Front Oncol 2022; 12:988119. [PMID: 36212456 PMCID: PMC9532844 DOI: 10.3389/fonc.2022.988119] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2022] [Accepted: 08/09/2022] [Indexed: 11/30/2022] Open
Abstract
Aquaporins (AQPs) are a family of small transmembrane proteins that selectively transport water and other small molecules and ions following an osmotic gradient across cell plasma membranes. This enables them to regulate numerous functions including water homeostasis, fat metabolism, proliferation, migration, and adhesion. Previous structural and functional studies highlight a strong biological relationship between AQP protein expression, localization, and key biological functions in normal and cancer tissues, where aberrant AQP expression correlates with tumorigenesis and metastasis. In this review, we discuss the roles of AQP1, AQP3, AQP4, AQP5, and AQP7 in breast cancer progression and metastasis, including the role of AQPs in the tumor microenvironment, to highlight potential contributions of stromal-derived to epithelial-derived AQPs to breast cancer. Emerging evidence identifies AQPs as predictors of response to cancer therapy and as targets for increasing their sensitivity to treatment. However, these studies have not evaluated the requirements for protein structure on AQP function within the context of breast cancer. We also examine how AQPs contribute to a patient's response to cancer treatment, existing AQP inhibitors and how AQPs could serve as novel predictive biomarkers of therapy response in breast cancer. Future studies also should evaluate AQP redundancy and compensation as mechanisms used to overcome aberrant AQP function. This review highlights the need for additional research into how AQPs contribute molecularly to therapeutic resistance and by altering the tumor microenvironment.
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Affiliation(s)
- Verodia Charlestin
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN, United States.,Harper Cancer Research Institute, University of Notre Dame, South Bend, IN, United States
| | - Daniel Fulkerson
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN, United States.,Harper Cancer Research Institute, University of Notre Dame, South Bend, IN, United States
| | - Carlos E Arias Matus
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN, United States.,Harper Cancer Research Institute, University of Notre Dame, South Bend, IN, United States.,Department of Biotechnology, Universidad Popular Autónoma del Estado de Puebla, Pue, Mexico
| | - Zachary T Walker
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN, United States.,Harper Cancer Research Institute, University of Notre Dame, South Bend, IN, United States
| | - Kevin Carthy
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN, United States.,Harper Cancer Research Institute, University of Notre Dame, South Bend, IN, United States
| | - Laurie E Littlepage
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN, United States.,Harper Cancer Research Institute, University of Notre Dame, South Bend, IN, United States
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Leite DL, Alsina PJ, de Medeiros Campos MM, de Sousa VA Jr, de Medeiros AAM. Unmanned Aerial Vehicle Propagation Channel over Vegetation and Lake Areas: First- and Second-Order Statistical Analysis. Sensors (Basel) 2021; 22:65. [PMID: 35009608 DOI: 10.3390/s22010065] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/15/2021] [Revised: 11/28/2021] [Accepted: 12/01/2021] [Indexed: 11/17/2022]
Abstract
The use of unmanned aerial vehicles (UAV) to provide services such as the Internet, goods delivery, and air taxis has become a reality in recent years. The use of these aircraft requires a secure communication between the control station and the UAV, which demands the characterization of the communication channel. This paper aims to present a measurement setup using an unmanned aircraft to acquire data for the characterization of the radio frequency channel in a propagation environment with particular vegetation (Caatinga) and a lake. This paper presents the following contributions: identification of the communication channel model that best describes the characteristics of communication; characterization of the effects of large-scale fading, such as path loss and log-normal shadowing; characterization of small-scale fading (multipath and Doppler); and estimation of the aircraft speed from the identified Doppler frequency.
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Schmidt JDR, Beitz E. Mutational Widening of Constrictions in a Formate-Nitrite/H + Transporter Enables Aquaporin-Like Water Permeability and Proton Conductance. J Biol Chem 2021; 298:101513. [PMID: 34929166 PMCID: PMC8749060 DOI: 10.1016/j.jbc.2021.101513] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2021] [Revised: 12/14/2021] [Accepted: 12/16/2021] [Indexed: 11/30/2022] Open
Abstract
The unrelated protein families of the microbial formate–nitrite transporters (FNTs) and aquaporins (AQP) likely adapted the same protein fold through convergent evolution. FNTs facilitate weak acid anion/H+ cotransport, whereas AQP water channels strictly exclude charged substrates including protons. The FNT channel–like transduction pathway bears two lipophilic constriction sites that sandwich a highly conserved histidine residue. Because of lacking experiments, the function of these constrictions is unclear, and the protonation status of the central histidine during substrate transport remains a matter of debate. Here, we introduced constriction-widening mutations into the prototypical FNT from Escherichia coli, FocA, and assayed formate/H+ transport properties, water/solute permeability, and proton conductance. We found that enlargement of these constrictions concomitantly decreased formate/formic acid transport. In contrast to wildtype FocA, the mutants were unable to make use of a transmembrane proton gradient as a driving force. A construct in which both constrictions were eliminated exhibited water permeability, similar to AQPs, although accompanied by a proton conductance. Our data indicate that the lipophilic constrictions mainly act as barriers to isolate the central histidine from the aqueous bulk preventing protonation via proton wires. These results are supportive of an FNT transport model in which the central histidine is uncharged, and weak acid substrate anion protonation occurs in the vestibule regions of the transporter before passing the constrictions.
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Affiliation(s)
- Jana D R Schmidt
- Department of Pharmaceutical and Medicinal Chemistry, Christian-Albrechts-University of Kiel, 24118 Kiel, Germany
| | - Eric Beitz
- Department of Pharmaceutical and Medicinal Chemistry, Christian-Albrechts-University of Kiel, 24118 Kiel, Germany.
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Fu S, Luo S. Quantifying Decoherence via Increases in Classicality. Entropy (Basel) 2021; 23:e23121594. [PMID: 34945900 PMCID: PMC8700208 DOI: 10.3390/e23121594] [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] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/01/2021] [Revised: 11/20/2021] [Accepted: 11/24/2021] [Indexed: 11/16/2022]
Abstract
As a direct consequence of the interplay between the superposition principle of quantum mechanics and the dynamics of open systems, decoherence is a recurring theme in both foundational and experimental exploration of the quantum realm. Decoherence is intimately related to information leakage of open systems and is usually formulated in the setup of "system + environment" as information acquisition of the environment (observer) from the system. As such, it has been mainly characterized via correlations (e.g., quantum mutual information, discord, and entanglement). Decoherence combined with redundant proliferation of the system information to multiple fragments of environment yields the scenario of quantum Darwinism, which is now a widely recognized framework for addressing the quantum-to-classical transition: the emergence of the apparent classical reality from the enigmatic quantum substrate. Despite the half-century development of the notion of decoherence, there are still many aspects awaiting investigations. In this work, we introduce two quantifiers of classicality via the Jordan product and uncertainty, respectively, and then employ them to quantify decoherence from an information-theoretic perspective. As a comparison, we also study the influence of the system on the environment.
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Affiliation(s)
- Shuangshuang Fu
- School of Mathematics and Physics, University of Science and Technology Beijing, Beijing 100083, China;
| | - Shunlong Luo
- Academy of Mathematics and Systems Science, Chinese Academy of Sciences, Beijing 100190, China
- School of Mathematical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
- Correspondence:
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Iliff AJ, Wang C, Ronan EA, Hake AE, Guo Y, Li X, Zhang X, Zheng M, Liu J, Grosh K, Duncan RK, Xu XZS. The nematode C. elegans senses airborne sound. Neuron 2021; 109:3633-3646.e7. [PMID: 34555314 PMCID: PMC8602785 DOI: 10.1016/j.neuron.2021.08.035] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2021] [Revised: 07/21/2021] [Accepted: 08/27/2021] [Indexed: 11/26/2022]
Abstract
Unlike olfaction, taste, touch, vision, and proprioception, which are
widespread across animal phyla, hearing is found only in vertebrates and some
arthropods. The vast majority of invertebrate species are thus considered
insensitive to sound. Here, we challenge this conventional view by showing that
the earless nematode C. elegans senses airborne sound at
frequencies reaching the kHz range. Sound vibrates C. elegans
skin, which acts as a pressure-to-displacement transducer similar to vertebrate
eardrum, activates sound-sensitive FLP/PVD neurons attached to the skin, and
evokes phonotaxis behavior. We identified two nAChRs that transduce sound
signals independently of ACh, revealing an unexpected function of nAChRs in
mechanosensation. Thus, the ability to sense airborne sound is not restricted to
vertebrates and arthropods as previously thought, and might have evolved
multiple times independently in the animal kingdom, suggesting convergent
evolution. Our studies also demonstrate that animals without ears may not be
presumed to be sound insensitive. Hearing is thought to exist only in vertebrates and some arthropods, but
not other animal phyla. Here, Xu and colleagues report that the earless nematode
C. elegans senses airborne sound and engages in phonotaxis.
Thus, hearing might have evolved multiple times independently in the animal
kingdom, suggesting convergent evolution.
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Affiliation(s)
- Adam J Iliff
- Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109, USA; Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Can Wang
- Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109, USA; Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI 48109, USA; College of Life Science and Technology, Key Laboratory of Molecular Biophysics of MOE, Huazhong University of Science and Technology, Wuhan, Hubei 430074, China
| | - Elizabeth A Ronan
- Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109, USA; Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Alison E Hake
- Department of Mechanical Engineering, University of Michigan, Ann Arbor, MI 48109, USA
| | - Yuling Guo
- Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109, USA; Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI 48109, USA; College of Life Science and Technology, Key Laboratory of Molecular Biophysics of MOE, Huazhong University of Science and Technology, Wuhan, Hubei 430074, China
| | - Xia Li
- Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109, USA; Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Xinxing Zhang
- Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109, USA; Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Maohua Zheng
- Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109, USA; Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Jianfeng Liu
- College of Life Science and Technology, Key Laboratory of Molecular Biophysics of MOE, Huazhong University of Science and Technology, Wuhan, Hubei 430074, China
| | - Karl Grosh
- Department of Mechanical Engineering, University of Michigan, Ann Arbor, MI 48109, USA; Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI 48109, USA
| | - R Keith Duncan
- Department of Otolaryngology-Head and Neck Surgery, University of Michigan, Ann Arbor, MI 48109, USA
| | - X Z Shawn Xu
- Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109, USA; Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI 48109, USA.
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Abstract
Cystic fibrosis (CF) is a recessive genetic disease caused by mutations in a gene encoding a protein called Cystic Fibrosis Transmembrane Conductance Regulator (CFTR). The CFTR protein is known to acts as a chloride (Cl-) channel expressed in the exocrine glands of several body systems where it also regulates other ion channels, including the epithelial sodium (Na+) channel (ENaC) that plays a key role in salt absorption. This function is crucial to the osmotic balance of the mucus and its viscosity. However, the pathophysiology of CF is more challenging than a mere dysregulation of epithelial ion transport, mainly resulting in impaired mucociliary clearance (MCC) with consecutive bronchiectasis and in exocrine pancreatic insufficiency. This review shows that the CFTR protein is not just a chloride channel. For a long time, research in CF has focused on abnormal Cl- and Na+ transport. Yet, the CFTR protein also regulates numerous other pathways, such as the transport of HCO3-, glutathione and thiocyanate, immune cells, and the metabolism of lipids. It influences the pH homeostasis of airway surface liquid and thus the MCC as well as innate immunity leading to chronic infection and inflammation, all of which are considered as key pathophysiological characteristics of CF.
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Affiliation(s)
- Laurence S. Hanssens
- Department of Pediatric Pulmonology and Cystic Fibrosis Clinic, Hôpital Universitaire des Enfants Reine Fabiola, Université Libre de Bruxelles (ULB), Avenue J.J. Crocq 15, 1020 Brussels, Belgium;
| | - Jean Duchateau
- Laboratoire Académique de Pédiatrie, Hôpital Universitaire des Enfants Reine Fabiola, Université Libre de Bruxelles (ULB), Avenue J.J. Crocq 15, 1020 Brussels, Belgium;
| | - Georges J. Casimir
- Department of Pediatric Pulmonology and Cystic Fibrosis Clinic, Hôpital Universitaire des Enfants Reine Fabiola, Université Libre de Bruxelles (ULB), Avenue J.J. Crocq 15, 1020 Brussels, Belgium;
- Laboratoire Académique de Pédiatrie, Hôpital Universitaire des Enfants Reine Fabiola, Université Libre de Bruxelles (ULB), Avenue J.J. Crocq 15, 1020 Brussels, Belgium;
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Li J, Yu K, Bao X, Liu X, Yao J. Patterns of eHealth Website User Engagement Based on Cross-site Clickstream Data: Correlational Study. J Med Internet Res 2021; 23:e29299. [PMID: 34397392 PMCID: PMC8398706 DOI: 10.2196/29299] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2021] [Revised: 04/28/2021] [Accepted: 05/24/2021] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND User engagement is a key performance variable for eHealth websites. However, most existing studies on user engagement either focus on a single website or depend on survey data. To date, we still lack an overview of user engagement on multiple eHealth websites derived from objective data. Therefore, it is relevant to provide a holistic view of user engagement on multiple eHealth websites based on cross-site clickstream data. OBJECTIVE This study aims to describe the patterns of user engagement on eHealth websites and investigate how platforms, channels, sex, and income influence user engagement on eHealth websites. METHODS The data used in this study were the clickstream data of 1095 mobile users, which were obtained from a large telecom company in Shanghai, China. The observation period covered 8 months (January 2017 to August 2017). Descriptive statistics, two-tailed t tests, and an analysis of variance were used for data analysis. RESULTS The medical category accounted for most of the market share of eHealth website visits (134,009/184,826, 72.51%), followed by the lifestyle category (46,870/184,826, 25.36%). The e-pharmacy category had the smallest market share, accounting for only 2.14% (3947/184,826) of the total visits. eHealth websites were characterized by very low visit penetration and relatively high user penetration. The distribution of engagement intensity followed a power law distribution. Visits to eHealth websites were highly concentrated. User engagement was generally high on weekdays but low on weekends. Furthermore, user engagement gradually increased from morning to noon. After noon, user engagement declined until it reached its lowest level at midnight. Lifestyle websites, followed by medical websites, had the highest customer loyalty. e-Pharmacy websites had the lowest customer loyalty. Popular eHealth websites, such as medical websites, can effectively provide referral traffic for lifestyle and e-pharmacy websites. However, the opposite is also true. Android users were more engaged in eHealth websites than iOS users. The engagement volume of app users was 4.85 times that of browser users, and the engagement intensity of app users was 4.22 times that of browser users. Male users had a higher engagement intensity than female users. Income negatively moderated the influence that platforms (Android vs iOS) had on user engagement. Low-income Android users were the most engaged in eHealth websites. Conversely, low-income iOS users were the least engaged in eHealth websites. CONCLUSIONS Clickstream data provide a new way to derive an overview of user engagement patterns on eHealth websites and investigate the influence that various factors (eg, platform, channel, sex, and income) have on engagement behavior. Compared with self-reported data from a questionnaire, cross-site clickstream data are more objective, accurate, and appropriate for pattern discovery. Many user engagement patterns and findings regarding the influential factors revealed by cross-site clickstream data have not been previously reported.
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Affiliation(s)
- Jia Li
- School of Business, East China University of Science and Technology, Shanghai, China
| | - Kanghui Yu
- School of Business, East China University of Science and Technology, Shanghai, China
| | - Xinyu Bao
- School of Business, East China University of Science and Technology, Shanghai, China
| | - Xuan Liu
- School of Business, East China University of Science and Technology, Shanghai, China
| | - Junping Yao
- Xi'an Research Institute of High Technology, Xi'an, China
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43
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Monasky MM, Micaglio E, Ignaccolo S, Pappone C. Further Considerations in Childhood-Onset Hypertrophic Cardiomyopathy Genetic Testing. Front Cardiovasc Med 2021; 8:698078. [PMID: 34235191 PMCID: PMC8255358 DOI: 10.3389/fcvm.2021.698078] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2021] [Accepted: 05/31/2021] [Indexed: 11/24/2022] Open
Affiliation(s)
- Michelle M Monasky
- Arrhythmia and Electrophysiology Department, IRCCS Policlinico San Donato, Milan, Italy
| | - Emanuele Micaglio
- Arrhythmia and Electrophysiology Department, IRCCS Policlinico San Donato, Milan, Italy
| | - Silvia Ignaccolo
- Arrhythmia and Electrophysiology Department, IRCCS Policlinico San Donato, Milan, Italy
| | - Carlo Pappone
- Arrhythmia and Electrophysiology Department, IRCCS Policlinico San Donato, Milan, Italy.,Vita-Salute San Raffaele University, Milan, Italy
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Li Q, Montell C. Mechanism for food texture preference based on grittiness. Curr Biol 2021; 31:1850-1861.e6. [PMID: 33657409 DOI: 10.1016/j.cub.2021.02.007] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2020] [Revised: 01/07/2021] [Accepted: 02/02/2021] [Indexed: 10/22/2022]
Abstract
An animal's decision to accept or reject a prospective food is based only, in part, on its chemical composition. Palatability is also greatly influenced by textural features including smoothness versus grittiness, which is influenced by particle sizes. Here, we demonstrate that Drosophila melanogaster is endowed with the ability to discriminate particle sizes in food and uses this information to decide whether a food is appealing. The decision depends on a mechanically activated channel, OSCA/TMEM63, which is conserved from plants to humans. We found that tmem63 is expressed in a multidendritic neuron (md-L) in the fly tongue. Loss of tmem63 impairs the activation of md-L by mechanical stimuli and the ability to choose food based on particle size. These findings reveal the first role for this evolutionarily conserved, mechanically activated TMEM63 channel in an animal and provide an explanation of how flies can sense and behaviorally respond to the texture of food provided by particles.
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Affiliation(s)
- Qiaoran Li
- Department of Molecular, Cellular, and Developmental Biology and the Neuroscience Research Institute, University of California, Santa Barbara, Santa Barbara, CA 93106, USA
| | - Craig Montell
- Department of Molecular, Cellular, and Developmental Biology and the Neuroscience Research Institute, University of California, Santa Barbara, Santa Barbara, CA 93106, USA.
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Salm EJ, Dunn PJ, Shan L, Yamasaki M, Malewicz NM, Miyazaki T, Park J, Sumioka A, Hamer RRL, He WW, Morimoto-Tomita M, LaMotte RH, Tomita S. TMEM163 Regulates ATP-Gated P2X Receptor and Behavior. Cell Rep 2021; 31:107704. [PMID: 32492420 DOI: 10.1016/j.celrep.2020.107704] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2019] [Revised: 04/14/2020] [Accepted: 05/06/2020] [Indexed: 12/18/2022] Open
Abstract
Fast purinergic signaling is mediated by ATP and ATP-gated ionotropic P2X receptors (P2XRs), and it is implicated in pain-related behaviors. The properties exhibited by P2XRs vary between those expressed in heterologous cells and in vivo. Several modulators of ligand-gated ion channels have recently been identified, suggesting that there are P2XR functional modulators in vivo. Here, we establish a genome-wide open reading frame (ORF) collection and perform functional screening to identify modulators of P2XR activity. We identify TMEM163, which specifically modulates the channel properties and pharmacology of P2XRs. We also find that TMEM163 is required for full function of the neuronal P2XR and a pain-related ATP-evoked behavior. These results establish TMEM163 as a critical modulator of P2XRs in vivo and a potential target for the discovery of drugs for treating pain.
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Affiliation(s)
- Elizabeth J Salm
- Department of Cellular and Molecular Physiology, Department of Neuroscience, Program in Cellular Neuroscience, Neurodegeneration and Repair, The Yale Kavli Institute, Yale University School of Medicine, New Haven, CT 06520, USA; Interdepartmental Neuroscience Program, Yale University School of Medicine, New Haven, CT 06520, USA
| | - Patrick J Dunn
- Department of Cellular and Molecular Physiology, Department of Neuroscience, Program in Cellular Neuroscience, Neurodegeneration and Repair, The Yale Kavli Institute, Yale University School of Medicine, New Haven, CT 06520, USA
| | - Lili Shan
- Department of Cellular and Molecular Physiology, Department of Neuroscience, Program in Cellular Neuroscience, Neurodegeneration and Repair, The Yale Kavli Institute, Yale University School of Medicine, New Haven, CT 06520, USA
| | - Miwako Yamasaki
- Department of Cellular and Molecular Physiology, Department of Neuroscience, Program in Cellular Neuroscience, Neurodegeneration and Repair, The Yale Kavli Institute, Yale University School of Medicine, New Haven, CT 06520, USA; Department of Anatomy, Faculty of Medicine, Hokkaido University, Sapporo, Japan
| | - Nathalie M Malewicz
- Department of Anesthesiology, Yale University School of Medicine, New Haven, CT 06520, USA
| | - Taisuke Miyazaki
- Department of Cellular and Molecular Physiology, Department of Neuroscience, Program in Cellular Neuroscience, Neurodegeneration and Repair, The Yale Kavli Institute, Yale University School of Medicine, New Haven, CT 06520, USA; Department of Anatomy, Faculty of Medicine, Hokkaido University, Sapporo, Japan
| | - Joongkyu Park
- Department of Cellular and Molecular Physiology, Department of Neuroscience, Program in Cellular Neuroscience, Neurodegeneration and Repair, The Yale Kavli Institute, Yale University School of Medicine, New Haven, CT 06520, USA
| | - Akio Sumioka
- Department of Cellular and Molecular Physiology, Department of Neuroscience, Program in Cellular Neuroscience, Neurodegeneration and Repair, The Yale Kavli Institute, Yale University School of Medicine, New Haven, CT 06520, USA
| | | | - Wei-Wu He
- OriGene Technologies, Inc., Rockville, MD 20850, USA
| | - Megumi Morimoto-Tomita
- Department of Cellular and Molecular Physiology, Department of Neuroscience, Program in Cellular Neuroscience, Neurodegeneration and Repair, The Yale Kavli Institute, Yale University School of Medicine, New Haven, CT 06520, USA
| | - Robert H LaMotte
- Department of Anesthesiology, Yale University School of Medicine, New Haven, CT 06520, USA
| | - Susumu Tomita
- Department of Cellular and Molecular Physiology, Department of Neuroscience, Program in Cellular Neuroscience, Neurodegeneration and Repair, The Yale Kavli Institute, Yale University School of Medicine, New Haven, CT 06520, USA; Interdepartmental Neuroscience Program, Yale University School of Medicine, New Haven, CT 06520, USA.
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Tsuchida K. [Electrophysiological Effects of Ionophore-induced Increases in Intracellular Na + in Cardiomyocytes]. YAKUGAKU ZASSHI 2021; 141:705-710. [PMID: 33952755 DOI: 10.1248/yakushi.20-00235] [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] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Na ionophores increase intracellular Na+ ([Na+]i). Membrane potentials and currents were measured using microelectrode and whole-cell patch-clamp techniques. Monensin (10-6-3×10-5 M) reduced the slope of the pacemaker potentials and shortened the action potential duration (APD) in sino-atrial nodal and Purkinje cells. Monensin (10-5 M) shortened the APD and reduced the amplitude of the plateau phase in ventricular myocytes. Monensin decreased the hyperpolarization-activated inward current (If), and it increased the transient outward potassium current (Ito) in Purkinje cells. In addition, monensin decreased the sodium current (INa), shifting the inactivation curve to the hyperpolarized direction. Moreover, monensin decreased the L-type calcium current (ICa) in ventricular myocytes. The Na+-Ca2+ exchange current (INa-Ca) was augmented particularly in the reverse mode, and the Na+-K+ pump current (INa-K) was also activated by monensin in cardiomyocytes. The ATP-activated potassium current (IK,ATP) could be induced by monensin. Notably, the inward rectifying K+ current (IK1), and the slow delayed outward K+ current (IKs) were not affected evidently by monensin. Collectively, alteration of [Na+]i can influence the activities of various ion channels and transporters. Thus, the significance of altered [Na+]i should be taken into consideration in the action of drugs affecting [Na+]i such as digitalis, Na+ channel blockers, and Na+ channel activating agents.
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Affiliation(s)
- Katsuharu Tsuchida
- Department of Rational Medicinal Science, Faculty of Pharmaceutical Sciences, Doshisha Women's College of Liberal Arts
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Wang C, Yang H, Xiang Y, Pang S, Bao C, Zhu L. A Synthetic Phospholipid Derivative Mediates Ion Transport Across Lipid Bilayers. Front Chem 2021; 9:667472. [PMID: 33996759 PMCID: PMC8116550 DOI: 10.3389/fchem.2021.667472] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2021] [Accepted: 04/06/2021] [Indexed: 11/13/2022] Open
Abstract
Inspired by the natural phospholipid structures for cell membrane, a synthetic phospholipid LC with an ion recognition group benzo-18-crown-6 (B18C6) moiety was prepared which has been demonstrated to be able to transport ions across the lipid bilayers. Fluorescent vesicle assay shows that LC has an excellent transport activity, and the EC50 value for K+ is 11.2 μM. The voltage clamp measurement exhibits regular square-like current signals with considerably long opening times, which indicates that LC achieves efficient ion transport through a channel mechanism and its single channel conductivity is 17 pS. Both of the vesicle assay and patch clamp tests indicate that LC has selectivity for Rb+, whose ionic radius is larger than the cavity of crown ether. It suggests that the sandwich interaction may play a key role in the ion transport across lipid bilayers. All these results help us to speculate that LC transports ions via a channel mechanism with a tetrameric aggregate as the active structure. In addition, LC had obvious toxicity to HeLa cells, and the IC50 was 100.0 μM after coculture for 36 h. We hope that this simple synthetic phospholipid will offer novel perspectives in the development of more efficient and selective ion transporters.
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Affiliation(s)
- Chenxi Wang
- Shanghai Key Laboratory of Functional Materials Chemistry, School of Chemistry and Molecular Engineering, East China University of Science and Technology, Shanghai, China
| | - Huiting Yang
- Shanghai Key Laboratory of Functional Materials Chemistry, School of Chemistry and Molecular Engineering, East China University of Science and Technology, Shanghai, China
| | - Yanxin Xiang
- Shanghai Key Laboratory of Functional Materials Chemistry, School of Chemistry and Molecular Engineering, East China University of Science and Technology, Shanghai, China
| | - Shihao Pang
- Shanghai Key Laboratory of Functional Materials Chemistry, School of Chemistry and Molecular Engineering, East China University of Science and Technology, Shanghai, China
| | - Chunyan Bao
- Shanghai Key Laboratory of Functional Materials Chemistry, School of Chemistry and Molecular Engineering, East China University of Science and Technology, Shanghai, China
| | - Linyong Zhu
- Shanghai Key Laboratory of Functional Materials Chemistry, School of Chemistry and Molecular Engineering, East China University of Science and Technology, Shanghai, China
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Goto H, Miyamoto M, Kihara A. Direct uptake of sphingosine-1-phosphate independent of phospholipid phosphatases. J Biol Chem 2021; 296:100605. [PMID: 33785361 PMCID: PMC8093947 DOI: 10.1016/j.jbc.2021.100605] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2020] [Revised: 03/23/2021] [Accepted: 03/26/2021] [Indexed: 12/20/2022] Open
Abstract
Sphingosine-1-phosphate (S1P) is a lipid mediator that is relatively abundant in plasma and plays an important role in the vascular and immune systems. To date, the only known mechanism for removing S1P from plasma has been dephosphorylation by phospholipid phosphatases (PLPPs) on the surface of cells in contact with the plasma. However, there remains a possibility that PLPP-independent dephosphorylation or direct S1P uptake into cells could occur. To examine these possibilities, here we generated triple KO (TKO) HAP1 cells that lacked all PLPPs (PLPP1–3) present in mammals. In the TKO cells, the intracellular metabolism of externally added deuterium-labeled S1P to ceramide was reduced to 17% compared with the WT cells, indicating that most extracellular S1P is dephosphorylated by PLPPs and then taken up into cells. However, this result also reveals the existence of a PLPP-independent S1P uptake pathway. Tracer experiments using [32P]S1P showed the existence of a direct S1P uptake pathway that functions without prior dephosphorylation. Overexpression of sphingolipid transporter 2 (SPNS2) or of major facilitator superfamily domain containing 2B (MFSD2B), both known S1P efflux transporters, in TKO cells increased the direct uptake of S1P, whereas KO of MFSD2B in TKO cells reduced this uptake. These results suggest that these are channel-type transporters and capable of not only exporting but also importing S1P. Furthermore, we observed that erythroid cells expressing MFSD2B, exhibited high S1P uptake activity. Our findings describing direct S1P uptake may contribute to the elucidation of the molecular mechanisms that regulate plasma S1P concentration.
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Affiliation(s)
- Hirotaka Goto
- Faculty of Pharmaceutical Sciences, Hokkaido University, Sapporo, Japan
| | | | - Akio Kihara
- Faculty of Pharmaceutical Sciences, Hokkaido University, Sapporo, Japan.
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Saikia C, Dym O, Altman-Gueta H, Gordon D, Reuveny E, Karbat I. A Molecular Lid Mechanism of K + Channel Blocker Action Revealed by a Cone Peptide. J Mol Biol 2021; 433:166957. [PMID: 33771569 DOI: 10.1016/j.jmb.2021.166957] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2020] [Revised: 03/08/2021] [Accepted: 03/16/2021] [Indexed: 12/15/2022]
Abstract
Many venomous organisms carry in their arsenal short polypeptides that block K+ channels in a highly selective manner. These toxins may compete with the permeating ions directly via a "plug" mechanism or indirectly via a "pore-collapse" mechanism. An alternative "lid" mechanism was proposed but remained poorly defined. Here we study the Drosophila Shaker channel block by Conkunitzin-S1 and Conkunitzin-C3, two highly similar toxins derived from cone venom. Despite their similarity, the two peptides exhibited differences in their binding poses and biophysical assays, implying discrete action modes. We show that while Conkunitzin-S1 binds tightly to the channel turret and acts via a "pore-collapse" mechanism, Conkunitzin-C3 does not contact this region. Instead, Conk-C3 uses a non-conserved Arg to divert the permeant ions and trap them in off-axis cryptic sites above the SF, a mechanism we term a "molecular-lid". Our study provides an atomic description of the "lid" K+ blocking mode and offers valuable insights for the design of therapeutics based on venom peptides.
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Affiliation(s)
- Chandamita Saikia
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Orly Dym
- Structural Proteomic Unit, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Hagit Altman-Gueta
- Department of Plant Molecular Biology and Ecology, Tel-Aviv University, Tel-Aviv 69978, Israel
| | - Dalia Gordon
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Eitan Reuveny
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot 76100, Israel.
| | - Izhar Karbat
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot 76100, Israel.
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Noterman MF, Chaubey K, Lin-Rahardja K, Rajadhyaksha AM, Pieper AA, Taylor EB. Dual-process brain mitochondria isolation preserves function and clarifies protein composition. Proc Natl Acad Sci U S A 2021; 118:e2019046118. [PMID: 33836587 PMCID: PMC7980376 DOI: 10.1073/pnas.2019046118] [Citation(s) in RCA: 3] [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] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
The brain requires continuously high energy production to maintain ion gradients and normal function. Mitochondria critically undergird brain energetics, and mitochondrial abnormalities feature prominently in neuropsychiatric disease. However, many unique aspects of brain mitochondria composition and function are poorly understood. Developing improved neuroprotective therapeutics thus requires more comprehensively understanding brain mitochondria, including accurately delineating protein composition and channel-transporter functional networks. However, obtaining pure mitochondria from the brain is especially challenging due to its distinctive lipid and cell structure properties. As a result, conflicting reports on protein localization to brain mitochondria abound. Here we illustrate this problem with the neuropsychiatric disease-associated L-type calcium channel Cav1.2α1 subunit previously observed in crude mitochondria. We applied a dual-process approach to obtain functionally intact versus compositionally pure brain mitochondria. One branch utilizes discontinuous density gradient centrifugation to isolate semipure mitochondria suitable for functional assays but unsuitable for protein localization because of endoplasmic reticulum (ER) contamination. The other branch utilizes self-forming density gradient ultracentrifugation to remove ER and yield ultrapure mitochondria that are suitable for investigating protein localization but functionally compromised. Through this process, we evaluated brain mitochondria protein content and observed the absence of Cav1.2α1 and other previously reported mitochondrial proteins, including the NMDA receptor, ryanodine receptor 1, monocarboxylate transporter 1, excitatory amino acid transporter 1, and glyceraldehyde 3-phosphate dehydrogenase. Conversely, we confirmed mitochondrial localization of several plasma membrane proteins previously reported to also localize to mitochondria. We expect this dual-process isolation procedure will enhance understanding of brain mitochondria in both health and disease.
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Affiliation(s)
- Maria F Noterman
- Interdisciplinary Graduate Program in Neuroscience, University of Iowa, Iowa City, IA 52242
| | - Kalyani Chaubey
- Harrington Discovery Institute, University Hospitals Cleveland Medical Center, Cleveland, OH 44106
- Department of Psychiatry, Case Western Reserve University, Cleveland, OH 44106
| | - Kristi Lin-Rahardja
- Department of Systems Biology and Bioinformatics, Case Western Reserve University, Cleveland, OH 44106
| | - Anjali M Rajadhyaksha
- Weill Cornell Autism Research Program, Weill Cornell Medicine of Cornell University, New York, NY 10065
- Pediatric Neurology, Pediatrics, Weill Cornell Medicine of Cornell University, New York, NY 10065
| | - Andrew A Pieper
- Harrington Discovery Institute, University Hospitals Cleveland Medical Center, Cleveland, OH 44106;
- Department of Psychiatry, Case Western Reserve University, Cleveland, OH 44106
- Weill Cornell Autism Research Program, Weill Cornell Medicine of Cornell University, New York, NY 10065
- Geriatric Research Education and Clinical Centers, Louis Stokes Cleveland VA Medical Center, Cleveland, OH 44106
- Department of Neuroscience, School of Medicine, Case Western Reserve University, Cleveland, OH 44106
| | - Eric B Taylor
- Department of Molecular Physiology and Biophysics, Carver College of Medicine, University of Iowa, Iowa City, IA 52242;
- Pappajohn Biomedical Institute, University of Iowa, Iowa City, IA 52242
- Fraternal Order of Eagles Diabetes Research Center, University of Iowa, Iowa City, IA 52242
- Holden Comprehensive Cancer Center, University of Iowa, Iowa City, IA 52242
- Iowa Neuroscience Institute, University of Iowa, Iowa City, IA 52242
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