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Cleary SR, Seflova J, Cho EE, Bisht K, Khandelia H, Espinoza-Fonseca LM, Robia SL. Phospholamban inhibits the cardiac calcium pump by interrupting an allosteric activation pathway. J Biol Chem 2024:107267. [PMID: 38583863 DOI: 10.1016/j.jbc.2024.107267] [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: 09/07/2023] [Revised: 03/20/2024] [Accepted: 04/02/2024] [Indexed: 04/09/2024] Open
Abstract
Phospholamban (PLB) is a transmembrane micropeptide that regulates the Ca2+ pump SERCA in cardiac muscle, but the physical mechanism of this regulation remains poorly understood. PLB reduces the Ca2+ sensitivity of active SERCA, increasing the Ca2+ concentration required for pump cycling. However, PLB does not decrease Ca2+ binding to SERCA when ATP is absent, suggesting PLB does not inhibit SERCA Ca2+ affinity. The prevailing explanation for these seemingly conflicting results is that PLB slows transitions in the SERCA enzymatic cycle associated with Ca2+ binding, altering transport Ca2+ dependence without actually affecting the equilibrium binding affinity of the Ca2+-coordinating sites. Here, we consider another hypothesis, that measurements of Ca2+ binding in the absence of ATP overlook important allosteric effects of nucleotide binding that increase SERCA Ca2+ binding affinity. We speculated that PLB inhibits SERCA by reversing this allostery. To test this, we used a fluorescent SERCA biosensor to quantify the Ca2+ affinity of non-cycling SERCA in the presence and absence of a non-hydrolyzable ATP-analog, AMPPCP. Nucleotide activation increased SERCA Ca2+ affinity, and this effect was reversed by co-expression of PLB. Interestingly, PLB had no effect on Ca2+ affinity in the absence of nucleotide. These results reconcile the previous conflicting observations from ATPase assays versus Ca2+ binding assays. Moreover, structural analysis of SERCA revealed a novel allosteric pathway connecting the ATP- and Ca2+-binding sites. We propose this pathway is disrupted by PLB binding. Thus, PLB reduces the equilibrium Ca2+ affinity of SERCA by interrupting allosteric activation of the pump by ATP.
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Affiliation(s)
- Sean R Cleary
- Department of Cell and Molecular Physiology, Loyola University Chicago, Maywood, IL, USA
| | - Jaroslava Seflova
- Department of Cell and Molecular Physiology, Loyola University Chicago, Maywood, IL, USA
| | - Ellen E Cho
- Department of Cell and Molecular Physiology, Loyola University Chicago, Maywood, IL, USA
| | - Konark Bisht
- PHYLIFE: Physical Life Science, Department of Physics, Chemistry, and Pharmacy, University of Southern Denmark, Odense, Denmark
| | - Himanshu Khandelia
- PHYLIFE: Physical Life Science, Department of Physics, Chemistry, and Pharmacy, University of Southern Denmark, Odense, Denmark
| | - L Michel Espinoza-Fonseca
- Division of Cardiovascular Medicine, Department of Internal Medicine, Center for Arrhythmia Research, University of Michigan, Ann Arbor, MI, USA
| | - Seth L Robia
- Department of Cell and Molecular Physiology, Loyola University Chicago, Maywood, IL, USA.
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2
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Ramos VM, Serna JDC, Vilas-Boas EA, Cabral-Costa JV, Cunha FM, Kataura T, Korolchuk VI, Kowaltowski AJ. Mitochondrial sodium/calcium exchanger (NCLX) regulates basal and starvation-induced autophagy through calcium signaling. FASEB J 2024; 38:e23454. [PMID: 38315457 DOI: 10.1096/fj.202301368rr] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2023] [Revised: 01/09/2024] [Accepted: 01/16/2024] [Indexed: 02/07/2024]
Abstract
Mitochondria shape intracellular Ca2+ signaling through the concerted activity of Ca2+ uptake via mitochondrial calcium uniporters and efflux by Na+ /Ca2+ exchangers (NCLX). Here, we describe a novel relationship among NCLX, intracellular Ca2+ , and autophagic activity. Conditions that stimulate autophagy in vivo and in vitro, such as caloric restriction and nutrient deprivation, upregulate NCLX expression in hepatic tissue and cells. Conversely, knockdown of NCLX impairs basal and starvation-induced autophagy. Similarly, acute inhibition of NCLX activity by CGP 37157 affects bulk and endoplasmic reticulum autophagy (ER-phagy) without significant impacts on mitophagy. Mechanistically, CGP 37157 inhibited the formation of FIP200 puncta and downstream autophagosome biogenesis. Inhibition of NCLX caused decreased cytosolic Ca2+ levels, and intracellular Ca2+ chelation similarly suppressed autophagy. Furthermore, chelation did not exhibit an additive effect on NCLX inhibition of autophagy, demonstrating that mitochondrial Ca2+ efflux regulates autophagy through the modulation of Ca2+ signaling. Collectively, our results show that the mitochondrial Ca2+ extrusion pathway through NCLX is an important regulatory node linking nutrient restriction and autophagy regulation.
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Affiliation(s)
- Vitor M Ramos
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, São Paulo, Brazil
| | - Julian D C Serna
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, São Paulo, Brazil
| | - Eloisa A Vilas-Boas
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, São Paulo, Brazil
| | | | - Fernanda M Cunha
- Departamento de Bioquímica, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, Brazil
| | - Tetsushi Kataura
- Biosciences Institute, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne, UK
| | - Viktor I Korolchuk
- Biosciences Institute, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne, UK
| | - Alicia J Kowaltowski
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, São Paulo, Brazil
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3
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Tomida S, Ishima T, Sawaki D, Imai Y, Nagai R, Aizawa K. Multi-Omics of Familial Thoracic Aortic Aneurysm and Dissection: Calcium Transport Impairment Predisposes Aortas to Dissection. Int J Mol Sci 2023; 24:15213. [PMID: 37894894 PMCID: PMC10607035 DOI: 10.3390/ijms242015213] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2023] [Revised: 10/10/2023] [Accepted: 10/11/2023] [Indexed: 10/29/2023] Open
Abstract
Several genetic defects, including a mutation in myosin heavy chain 11 (Myh11), are reported to cause familial thoracic aortic aneurysm and dissection (FTAAD). We recently showed that mice lacking K1256 of Myh11 developed aortic dissection when stimulated with angiotensin II, despite the absence of major pathological phenotypic abnormalities prior to stimulation. In this study, we used a comprehensive, data-driven, unbiased, multi-omics approach to find underlying changes in transcription and metabolism that predispose the aorta to dissection in mice harboring the Myh11 K1256del mutation. Pathway analysis of transcriptomes showed that genes involved in membrane transport were downregulated in homozygous mutant (Myh11ΔK/ΔK) aortas. Furthermore, expanding the analysis with metabolomics showed that two mechanisms that raise the cytosolic Ca2+ concentration-multiple calcium channel expression and ADP-ribose synthesis-were attenuated in Myh11ΔK/ΔK aortas. We suggest that the impairment of the Ca2+ influx attenuates aortic contraction and that suboptimal contraction predisposes the aorta to dissection.
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Affiliation(s)
- Shota Tomida
- Division of Clinical Pharmacology, Department of Pharmacology, Jichi Medical University, Shimotsuke 329-0498, Tochigi, Japan; (S.T.); (T.I.); (D.S.); (Y.I.)
| | - Tamaki Ishima
- Division of Clinical Pharmacology, Department of Pharmacology, Jichi Medical University, Shimotsuke 329-0498, Tochigi, Japan; (S.T.); (T.I.); (D.S.); (Y.I.)
| | - Daigo Sawaki
- Division of Clinical Pharmacology, Department of Pharmacology, Jichi Medical University, Shimotsuke 329-0498, Tochigi, Japan; (S.T.); (T.I.); (D.S.); (Y.I.)
| | - Yasushi Imai
- Division of Clinical Pharmacology, Department of Pharmacology, Jichi Medical University, Shimotsuke 329-0498, Tochigi, Japan; (S.T.); (T.I.); (D.S.); (Y.I.)
| | - Ryozo Nagai
- Jichi Medical University, Shimotsuke 329-0498, Tochigi, Japan;
| | - Kenichi Aizawa
- Division of Clinical Pharmacology, Department of Pharmacology, Jichi Medical University, Shimotsuke 329-0498, Tochigi, Japan; (S.T.); (T.I.); (D.S.); (Y.I.)
- Clinical Pharmacology Center, Jichi Medical University Hospital, Shimotsuke 329-0498, Tochigi, Japan
- Division of Translational Research, Clinical Research Center, Jichi Medical University Hospital, Shimotsuke 329-0498, Tochigi, Japan
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Simon AA, Navarro-Retamal C, Feijó JA. Merging Signaling with Structure: Functions and Mechanisms of Plant Glutamate Receptor Ion Channels. Annu Rev Plant Biol 2023; 74:415-452. [PMID: 36854472 DOI: 10.1146/annurev-arplant-070522-033255] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Plant glutamate receptor-like (GLR) genes encode ion channels with demonstrated roles in electrical and calcium (Ca2+) signaling. The expansion of the GLR family along the lineage of land plants, culminating in the appearance of a multiclade system among flowering plants, has been a topic of interest since their discovery nearly 25 years ago. GLRs are involved in many physiological processes, from wound signaling to transcriptional regulation to sexual reproduction. Emerging evidence supports the notion that their fundamental functions are conserved among different groups of plants as well. In this review, we update the physiological and genetic evidence for GLRs, establishing their role in signaling and cell-cell communication. Special emphasis is given to the recent discussion of GLRs' atomic structures. Along with functional assays, a structural view of GLRs' molecular organization presents a window for novel hypotheses regarding the molecular mechanisms underpinning signaling associated with the ionic fluxes that GLRs regulate. Newly uncovered transcriptional regulations associated with GLRs-which propose the involvement of genes from all clades ofArabidopsis thaliana in ways not previously observed-are discussed in the context of the broader impacts of GLR activity. We posit that the functions of GLRs in plant biology are probably much broader than anticipated, but describing their widespread involvement will only be possible with (a) a comprehensive understanding of the channel's properties at the molecular and structural levels, including protein-protein interactions, and (b) the design of new genetic approaches to explore stress and pathogen responses where precise transcriptional control may result in more precise testable hypotheses to overcome their apparent functional redundancies.
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Affiliation(s)
- Alexander A Simon
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, Maryland, USA;
- Department of Anesthesiology, Weill Cornell Medicine, New York, NY, USA;
| | - Carlos Navarro-Retamal
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, Maryland, USA;
| | - José A Feijó
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, Maryland, USA;
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Cabral-Costa JV, Vicente-Gutiérrez C, Agulla J, Lapresa R, Elrod JW, Almeida Á, Bolaños JP, Kowaltowski AJ. Mitochondrial sodium/calcium exchanger NCLX regulates glycolysis in astrocytes, impacting on cognitive performance. J Neurochem 2023; 165:521-535. [PMID: 36563047 PMCID: PMC10478152 DOI: 10.1111/jnc.15745] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2022] [Revised: 12/11/2022] [Accepted: 12/12/2022] [Indexed: 12/24/2022]
Abstract
Intracellular Ca2+ concentrations are strictly controlled by plasma membrane transporters, the endoplasmic reticulum, and mitochondria, in which Ca2+ uptake is mediated by the mitochondrial calcium uniporter complex (MCUc), while efflux occurs mainly through the mitochondrial Na+ /Ca2+ exchanger (NCLX). RNAseq database repository searches led us to identify the Nclx transcript as highly enriched in astrocytes when compared with neurons. To assess the role of NCLX in mouse primary culture astrocytes, we inhibited its function both pharmacologically or genetically. This resulted in re-shaping of cytosolic Ca2+ signaling and a metabolic shift that increased glycolytic flux and lactate secretion in a Ca2+ -dependent manner. Interestingly, in vivo genetic deletion of NCLX in hippocampal astrocytes improved cognitive performance in behavioral tasks, whereas hippocampal neuron-specific deletion of NCLX impaired cognitive performance. These results unveil a role for NCLX as a novel modulator of astrocytic glucose metabolism, impacting on cognition.
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Affiliation(s)
- João Victor Cabral-Costa
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, São Paulo, Brazil
- Institute of Functional Biology and Genomics, University of Salamanca-CSIC, Salamanca, Spain
| | - Carlos Vicente-Gutiérrez
- Institute of Functional Biology and Genomics, University of Salamanca-CSIC, Salamanca, Spain
- Centro de Investigación Biomédica en Red Sobre Fragilidad y Envejecimiento Saludable (CIBERFES), Instituto de Salud Carlos III, Madrid, Spain
- Institute of Biomedical Research of Salamanca, University Hospital of Salamanca, University of Salamanca-CSIC, Salamanca, Spain
| | - Jesús Agulla
- Institute of Functional Biology and Genomics, University of Salamanca-CSIC, Salamanca, Spain
- Institute of Biomedical Research of Salamanca, University Hospital of Salamanca, University of Salamanca-CSIC, Salamanca, Spain
| | - Rebeca Lapresa
- Institute of Functional Biology and Genomics, University of Salamanca-CSIC, Salamanca, Spain
- Institute of Biomedical Research of Salamanca, University Hospital of Salamanca, University of Salamanca-CSIC, Salamanca, Spain
| | - John W. Elrod
- Center for Translational Medicine, Lewis Katz School of Medicine at Temple University, Philadelphia, Pennsylvania, USA
| | - Ángeles Almeida
- Institute of Functional Biology and Genomics, University of Salamanca-CSIC, Salamanca, Spain
- Institute of Biomedical Research of Salamanca, University Hospital of Salamanca, University of Salamanca-CSIC, Salamanca, Spain
| | - Juan P. Bolaños
- Institute of Functional Biology and Genomics, University of Salamanca-CSIC, Salamanca, Spain
- Centro de Investigación Biomédica en Red Sobre Fragilidad y Envejecimiento Saludable (CIBERFES), Instituto de Salud Carlos III, Madrid, Spain
- Institute of Biomedical Research of Salamanca, University Hospital of Salamanca, University of Salamanca-CSIC, Salamanca, Spain
| | - Alicia J. Kowaltowski
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, São Paulo, Brazil
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Roopnarine O, Yuen SL, Thompson AR, Roelike LN, Rebbeck RT, Bidwell PA, Aldrich CC, Cornea RL, Thomas DD. FRET assay for live-cell high-throughput screening of the cardiac SERCA pump yields multiple classes of small-molecule allosteric modulators. Res Sq 2023:rs.3.rs-2596384. [PMID: 36909610 PMCID: PMC10002828 DOI: 10.21203/rs.3.rs-2596384/v1] [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: 03/04/2023]
Abstract
We have used FRET-based biosensors in live cells, in a robust high-throughput screening (HTS) platform, to identify small-molecules that alter the structure and activity of the cardiac sarco/endoplasmic reticulum calcium ATPase (SERCA2a). Our primary aim is to discover drug-like small-molecule activators that improve SERCA’s function for the treatment of heart failure. We have previously demonstrated the use of an intramolecular FRET biosensor, based on human SERCA2a, by screening a small validation library using novel microplate readers that can detect the fluorescence lifetime or emission spectrum with high speed, precision, and resolution. Here we report results from a 50,000-compound screen using the same biosensor, with hit compounds functionally evaluated using Ca 2+ -ATPase and Ca 2+ -transport assays. We focused on 18 hit compounds, from which we identified eight structurally unique compounds and four compound classes as SERCA modulators, approximately half of which are activators and half are inhibitors. While both activators and inhibitors have therapeutic potential, the activators establish the basis for future testing in heart disease models and lead development, toward pharmaceutical therapy for heart failure.
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7
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Vilas-Boas EA, Cabral-Costa JV, Ramos VM, Caldeira da Silva CC, Kowaltowski AJ. Goldilocks calcium concentrations and the regulation of oxidative phosphorylation: Too much, too little, or just right. J Biol Chem 2023; 299:102904. [PMID: 36642177 PMCID: PMC9947387 DOI: 10.1016/j.jbc.2023.102904] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [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: 08/26/2022] [Revised: 12/21/2022] [Accepted: 12/23/2022] [Indexed: 01/14/2023] Open
Abstract
Calcium (Ca2+) is a key regulator in diverse intracellular signaling pathways and has long been implicated in metabolic control and mitochondrial function. Mitochondria can actively take up large amounts of Ca2+, thereby acting as important intracellular Ca2+ buffers and affecting cytosolic Ca2+ transients. Excessive mitochondrial matrix Ca2+ is known to be deleterious due to opening of the mitochondrial permeability transition pore (mPTP) and consequent membrane potential dissipation, leading to mitochondrial swelling, rupture, and cell death. Moderate Ca2+ within the organelle, on the other hand, can directly or indirectly activate mitochondrial matrix enzymes, possibly impacting on ATP production. Here, we aimed to determine in a quantitative manner if extra- or intramitochondrial Ca2+ modulates oxidative phosphorylation in mouse liver mitochondria and intact hepatocyte cell lines. To do so, we monitored the effects of more modest versus supraphysiological increases in cytosolic and mitochondrial Ca2+ on oxygen consumption rates. Isolated mitochondria present increased respiratory control ratios (a measure of oxidative phosphorylation efficiency) when incubated with low (2.4 ± 0.6 μM) and medium (22.0 ± 2.4 μM) Ca2+ concentrations in the presence of complex I-linked substrates pyruvate plus malate and α-ketoglutarate, respectively, but not complex II-linked succinate. In intact cells, both low and high cytosolic Ca2+ led to decreased respiratory rates, while ideal rates were present under physiological conditions. High Ca2+ decreased mitochondrial respiration in a substrate-dependent manner, mediated by mPTP. Overall, our results uncover a Goldilocks effect of Ca2+ on liver mitochondria, with specific "just right" concentrations that activate oxidative phosphorylation.
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Affiliation(s)
- Eloisa A Vilas-Boas
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, São Paulo, São Paulo, Brazil.
| | - João Victor Cabral-Costa
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, São Paulo, São Paulo, Brazil
| | - Vitor M Ramos
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, São Paulo, São Paulo, Brazil
| | | | - Alicia J Kowaltowski
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, São Paulo, São Paulo, Brazil.
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Zhang C, Feng Y, Balutowski A, Miner GE, Rivera-Kohr DA, Hrabak MR, Sullivan KD, Guo A, Calderin JD, Fratti RA. The interdependent transport of yeast vacuole Ca 2+ and H + and the role of phosphatidylinositol 3,5-bisphosphate. J Biol Chem 2022; 298:102672. [PMID: 36334632 PMCID: PMC9706634 DOI: 10.1016/j.jbc.2022.102672] [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: 09/27/2022] [Revised: 10/30/2022] [Accepted: 10/31/2022] [Indexed: 11/27/2022] Open
Abstract
Yeast vacuoles are acidified by the v-type H+-ATPase (V-ATPase) that is comprised of the membrane embedded VO complex and the soluble cytoplasmic V1 complex. The assembly of the V1-VO holoenzyme on the vacuole is stabilized in part through interactions between the VO a-subunit ortholog Vph1 and the lipid phosphatidylinositol 3,5-bisphosphate (PI(3,5)P2). PI(3,5)P2 also affects vacuolar Ca2+ release through the channel Yvc1 and uptake through the Ca2+ pump Pmc1. Here, we asked if H+ and Ca2+ transport activities were connected through PI(3,5)P2. We found that overproduction of PI(3,5)P2 by the hyperactive fab1T2250A mutant augmented vacuole acidification, whereas the kinase-inactive fab1EEE mutant attenuated the formation of a H+ gradient. Separately, we tested the effects of excess Ca2+ on vacuole acidification. Adding micromolar Ca2+ blocked vacuole acidification, whereas chelating Ca2+ accelerated acidification. The effect of adding Ca2+ on acidification was eliminated when the Ca2+/H+ antiporter Vcx1 was absent, indicating that the vacuolar H+ gradient can collapse during Ca2+ stress through Vcx1 activity. This, however, was independent of PI(3,5)P2, suggesting that PI(3,5)P2 plays a role in submicromolar Ca2+ flux but not under Ca2+ shock. To see if the link between Ca2+ and H+ transport was bidirectional, we examined Ca2+ transport when vacuole acidification was inhibited. We found that Ca2+ transport was inhibited by halting V-ATPase activity with Bafilomycin or neutralizing vacuolar pH with chloroquine. Together, these data show that Ca2+ transport and V-ATPase efficacy are connected but not necessarily through PI(3,5)P2.
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Affiliation(s)
- Chi Zhang
- Department of Biochemistry, University of Illinois Urbana-Champaign, Urbana, Illinois, USA
| | - Yilin Feng
- Department of Biochemistry, University of Illinois Urbana-Champaign, Urbana, Illinois, USA
| | - Adam Balutowski
- Department of Biochemistry, University of Illinois Urbana-Champaign, Urbana, Illinois, USA
| | - Gregory E Miner
- Department of Biochemistry, University of Illinois Urbana-Champaign, Urbana, Illinois, USA
| | - David A Rivera-Kohr
- Department of Biochemistry, University of Illinois Urbana-Champaign, Urbana, Illinois, USA
| | - Michael R Hrabak
- Department of Biochemistry, University of Illinois Urbana-Champaign, Urbana, Illinois, USA
| | - Katherine D Sullivan
- Department of Biochemistry, University of Illinois Urbana-Champaign, Urbana, Illinois, USA
| | - Annie Guo
- Department of Biochemistry, University of Illinois Urbana-Champaign, Urbana, Illinois, USA
| | - Jorge D Calderin
- Department of Biochemistry, University of Illinois Urbana-Champaign, Urbana, Illinois, USA
| | - Rutilio A Fratti
- Department of Biochemistry, University of Illinois Urbana-Champaign, Urbana, Illinois, USA; Center for Biophysics & Quantitative Biology, University of Illinois Urbana-Champaign, Urbana, Illinois, USA.
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Bidwell PA, Yuen SL, Li J, Berg K, Rebbeck RT, Aldrich CC, Roopnarine O, Cornea RL, Thomas DD. A Large-Scale High-Throughput Screen for Modulators of SERCA Activity. Biomolecules 2022; 12. [PMID: 36551215 DOI: 10.3390/biom12121789] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2022] [Revised: 11/21/2022] [Accepted: 11/25/2022] [Indexed: 12/03/2022] Open
Abstract
The sarco/endoplasmic reticulum Ca-ATPase (SERCA) is a P-type ion pump that transports Ca2+ from the cytosol into the endoplasmic/sarcoplasmic reticulum (ER/SR) in most mammalian cells. It is critically important in muscle, facilitating relaxation and enabling subsequent contraction. Increasing SERCA expression or specific activity can alleviate muscle dysfunction, most notably in the heart, and we seek to develop small-molecule drug candidates that activate SERCA. Therefore, we adapted an NADH-coupled assay, measuring Ca-dependent ATPase activity of SERCA, to high-throughput screening (HTS) format, and screened a 46,000-compound library of diverse chemical scaffolds. This HTS platform yielded numerous hits that reproducibly alter SERCA Ca-ATPase activity, with few false positives. The top 19 activating hits were further tested for effects on both Ca-ATPase and Ca2+ transport, in both cardiac and skeletal SR. Nearly all hits increased Ca2+ uptake in both cardiac and skeletal SR, with some showing isoform specificity. Furthermore, dual analysis of both activities identified compounds with a range of effects on Ca2+-uptake and ATPase, which fit into distinct classifications. Further study will be needed to identify which classifications are best suited for therapeutic use. These results reinforce the need for robust secondary assays and criteria for selection of lead compounds, before undergoing HTS on a larger scale.
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Bernardi P, Carraro M, Lippe G. The mitochondrial permeability transition: Recent progress and open questions. FEBS J 2022; 289:7051-7074. [PMID: 34710270 PMCID: PMC9787756 DOI: 10.1111/febs.16254] [Citation(s) in RCA: 63] [Impact Index Per Article: 31.5] [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: 10/05/2021] [Accepted: 10/27/2021] [Indexed: 01/13/2023]
Abstract
Major progress has been made in defining the basis of the mitochondrial permeability transition, a Ca2+ -dependent permeability increase of the inner membrane that has puzzled mitochondrial research for almost 70 years. Initially considered an artefact of limited biological interest by most, over the years the permeability transition has raised to the status of regulator of mitochondrial ion homeostasis and of druggable effector mechanism of cell death. The permeability transition is mediated by opening of channel(s) modulated by matrix cyclophilin D, the permeability transition pore(s) (PTP). The field has received new impulse (a) from the hypothesis that the PTP may originate from a Ca2+ -dependent conformational change of F-ATP synthase and (b) from the reevaluation of the long-standing hypothesis that it originates from the adenine nucleotide translocator (ANT). Here, we provide a synthetic account of the structure of ANT and F-ATP synthase to discuss potential and controversial mechanisms through which they may form high-conductance channels; and review some intriguing findings from the wealth of early studies of PTP modulation that still await an explanation. We hope that this review will stimulate new experiments addressing the many outstanding problems, and thus contribute to the eventual solution of the puzzle of the permeability transition.
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Affiliation(s)
- Paolo Bernardi
- Department of Biomedical Sciences and CNR Neuroscience InstituteUniversity of PadovaItaly
| | - Michela Carraro
- Department of Biomedical Sciences and CNR Neuroscience InstituteUniversity of PadovaItaly
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11
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Reyes JV, Medina PMB. Renal calcium and magnesium handling in Gitelman syndrome. Am J Transl Res 2022; 14:1-19. [PMID: 35173827 PMCID: PMC8829599] [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] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2021] [Accepted: 11/24/2021] [Indexed: 06/14/2023]
Abstract
Gitelman syndrome (GS) is an autosomal recessive salt-losing tubulopathy caused by biallelic inactivating mutations in the SLC12A3 gene. This gene encodes the thiazide-sensitive sodium-chloride cotransporter (NCC) which is exclusively expressed in the distal convoluted tubules (DCT). GS patients classically present with hypokalemic metabolic alkalosis with hypocalciuria and hypomagnesemia. While hypokalemia and metabolic alkalosis are easily explained by effects of the genotypic defect in GS, the mechanisms by which hypomagnesemia and hypocalciuria develop in GS are poorly understood. In this review, we aim to achieve three major objectives. First, present a concise discussion about current understanding on physiologic calcium and magnesium handling in the DCT. Second, integrate expression data from studies on calciotropic and magnesiotropic proteins relevant to the GS disease state. Lastly, provide insights into the possible mechanisms of calcium-magnesium crosstalk relating to the co-occurrence of hypocalciuria and hypomagnesemia in GS models. Our analyses highlight specific areas of study that are valuable in elucidating possible molecular pathways of hypocalciuria and hypomagnesemia in GS.
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Affiliation(s)
- Jeremiah V Reyes
- Biological Models Laboratory, Department of Biochemistry and Molecular Biology, College of Medicine, University of the Philippines Manila Ermita, Manila 1000, Philippines
| | - Paul Mark B Medina
- Biological Models Laboratory, Department of Biochemistry and Molecular Biology, College of Medicine, University of the Philippines Manila Ermita, Manila 1000, Philippines
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12
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Yan S, Hu Q, Wei Y, Jiang Q, Yin M, Dong M, Shen J, Du X. Calcium nutrition nanoagent rescues tomatoes from mosaic virus disease by accelerating calcium transport and activating antiviral immunity. Front Plant Sci 2022; 13:1092774. [PMID: 36561462 PMCID: PMC9764000 DOI: 10.3389/fpls.2022.1092774] [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] [Subscribe] [Scholar Register] [Received: 11/08/2022] [Accepted: 11/24/2022] [Indexed: 05/04/2023]
Abstract
As an essential structural, metabolic and signaling element, calcium shows low remobilization from old to young tissues in plants, restricting the nutrient-use efficiency and control efficacy against mosaic virus disease. Nanotechnology has been applied to prevent/minimize nutrient losses and improve the accessibility of poorly-available nutrients. Herein, the current study applied a star polycation (SPc) to prepare a calcium nutrition nanoagent. The SPc could assemble with calcium glycinate through hydrogen bond and Van der Waals force, forming stable spherical particles with nanoscale size (17.72 nm). Transcriptomic results revealed that the calcium glycinate/SPc complex could activate the expression of many transport-related genes and disease resistance genes in tomatoes, suggesting the enhanced transport and antiviral immunity of SPc-loaded calcium glycinate. Reasonably, the calcium transport was accelerated by 3.17 times into tomato leaves with the help of SPc, and the protective effect of calcium glycinate was remarkably improved to 77.40% and 67.31% toward tomato mosaic virus with the help of SPc after the third and fifth applications. Furthermore, SPc-loaded calcium glycinate could be applied to increase the leaf photosynthetic rate and control the unusual fast growth of tomatoes. The current study is the first success to apply nano-delivery system for enhanced calcium transport and antiviral immunity, which is beneficial for increasing nutrient-use efficiency and shows good prospects for field application.
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Affiliation(s)
- Shuo Yan
- Department of Plant Biosecurity and MARA Key Laboratory of Surveillance and Management for Plant Quarantine Pests, College of Plant Protection, China Agricultural University, Beijing, China
| | - Qian Hu
- Development Center for Science and Technology, Ministry of Agriculture and Rural Affairs, Beijing, China
| | - Ying Wei
- Department of Plant Biosecurity and MARA Key Laboratory of Surveillance and Management for Plant Quarantine Pests, College of Plant Protection, China Agricultural University, Beijing, China
| | - Qinhong Jiang
- Department of Plant Biosecurity and MARA Key Laboratory of Surveillance and Management for Plant Quarantine Pests, College of Plant Protection, China Agricultural University, Beijing, China
| | - Meizhen Yin
- State Key Laboratory of Chemical Resource Engineering, Beijing Lab of Biomedical Materials, Beijing University of Chemical Technology, Beijing, China
| | - Min Dong
- Department of Plant Biosecurity and MARA Key Laboratory of Surveillance and Management for Plant Quarantine Pests, College of Plant Protection, China Agricultural University, Beijing, China
| | - Jie Shen
- Department of Plant Biosecurity and MARA Key Laboratory of Surveillance and Management for Plant Quarantine Pests, College of Plant Protection, China Agricultural University, Beijing, China
- *Correspondence: Xiangge Du, ; Jie Shen,
| | - Xiangge Du
- Department of Plant Biosecurity and MARA Key Laboratory of Surveillance and Management for Plant Quarantine Pests, College of Plant Protection, China Agricultural University, Beijing, China
- *Correspondence: Xiangge Du, ; Jie Shen,
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13
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Peng L, Du J, Zhang R, Zhu N, Zhao H, Zhao Q, Yu Q, Li M. The Transient Receptor Potential Channel Yvc1 Deletion Recovers the Growth Defect of Calcineurin Mutant Under Endoplasmic Reticulum Stress in Candida albicans. Front Microbiol 2021; 12:752670. [PMID: 34917046 PMCID: PMC8669648 DOI: 10.3389/fmicb.2021.752670] [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: 08/03/2021] [Accepted: 10/07/2021] [Indexed: 11/24/2022] Open
Abstract
Transient receptor potential (TRP) channel Yvc1 was related with hyphal growth, oxidative stress response, and pathogenicity. Calcineurin subunit Cnb1 was activated immediately in yeasts when exposed to severe stimulation. However, the relationship between Yvc1 and Cnb1-governed calcium ions and endoplasmic reticulum (ER) stress response remains unrevealed. In this study, we found that the mutant cnb1Δ/Δ was sensitive to TN, which was related with the overexpression of membrane calcium ion channels that could increase the cytosol calcium concentration. However, the growth of the cnb1Δ/Δyvc1Δ/Δ mutant was recovered and its cell vitality was better than the cnb1Δ/Δ strain. Meanwhile, the cellular calcium concentration was decreased and its fluctuation was weakened under ER stress in the cnb1Δ/Δyvc1Δ/Δ strain. To verify the regulation role of Yvc1 in the calcium concentration, we found that the addition of CaCl2 led to the worse viability, while the growth state was relieved under the treatment of EGTA in the cnb1Δ/Δ strain. In conclusion, the deletion of YVC1 could reduce the cellular calcium and relieve the ER stress sensitivity of the cnb1Δ/Δ strain. Thereby, our findings shed a novel light on the relationship between the Yvc1-governed cellular calcium concentration and ER stress response in C. albicans.
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Affiliation(s)
- Liping Peng
- Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, College of Life Sciences, Nankai University, Tianjin, China
| | - Jiawen Du
- Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, College of Life Sciences, Nankai University, Tianjin, China
| | - Runfan Zhang
- Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, College of Life Sciences, Nankai University, Tianjin, China
| | - Nali Zhu
- Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, College of Life Sciences, Nankai University, Tianjin, China
| | - He Zhao
- Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, College of Life Sciences, Nankai University, Tianjin, China
| | - Qiang Zhao
- Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, College of Life Sciences, Nankai University, Tianjin, China
| | - Qilin Yu
- Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, College of Life Sciences, Nankai University, Tianjin, China
| | - Mingchun Li
- Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, College of Life Sciences, Nankai University, Tianjin, China
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14
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Fecher-Trost C, Wolske K, Wesely C, Löhr H, Klawitter DS, Weissgerber P, Gradhand E, Burren CP, Mason AE, Winter M, Wissenbach U. Mutations That Affect the Surface Expression of TRPV6 Are Associated with the Upregulation of Serine Proteases in the Placenta of an Infant. Int J Mol Sci 2021; 22:12694. [PMID: 34884497 PMCID: PMC8657554 DOI: 10.3390/ijms222312694] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [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: 11/05/2021] [Revised: 11/18/2021] [Accepted: 11/22/2021] [Indexed: 02/07/2023] Open
Abstract
Recently, we reported a case of an infant with neonatal severe under-mineralizing skeletal dysplasia caused by mutations within both alleles of the TRPV6 gene. One mutation results in an in frame stop codon (R510stop) that leads to a truncated, nonfunctional TRPV6 channel, and the second in a point mutation (G660R) that, surprisingly, does not affect the Ca2+ permeability of TRPV6. We mimicked the subunit composition of the unaffected heterozygous parent and child by coexpressing the TRPV6 G660R and R510stop mutants and combinations with wild type TRPV6. We show that both the G660R and R510stop mutant subunits are expressed and result in decreased calcium uptake, which is the result of the reduced abundancy of functional TRPV6 channels within the plasma membrane. We compared the proteomic profiles of a healthy placenta with that of the diseased infant and detected, exclusively in the latter two proteases, HTRA1 and cathepsin G. Our results implicate that the combination of the two mutant TRPV6 subunits, which are expressed in the placenta of the diseased child, is responsible for the decreased calcium uptake, which could explain the skeletal dysplasia. In addition, placental calcium deficiency also appears to be associated with an increase in the expression of proteases.
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Affiliation(s)
- Claudia Fecher-Trost
- Experimental and Clinical Pharmacology and Toxicology, Center for Molecular Signaling (PZMS), Saarland University, Buildings 61.4 and 46, 66421 Homburg, Germany; (C.F.-T.); (K.W.); (C.W.); (H.L.); (D.S.K.); (P.W.); (M.W.)
| | - Karin Wolske
- Experimental and Clinical Pharmacology and Toxicology, Center for Molecular Signaling (PZMS), Saarland University, Buildings 61.4 and 46, 66421 Homburg, Germany; (C.F.-T.); (K.W.); (C.W.); (H.L.); (D.S.K.); (P.W.); (M.W.)
| | - Christine Wesely
- Experimental and Clinical Pharmacology and Toxicology, Center for Molecular Signaling (PZMS), Saarland University, Buildings 61.4 and 46, 66421 Homburg, Germany; (C.F.-T.); (K.W.); (C.W.); (H.L.); (D.S.K.); (P.W.); (M.W.)
| | - Heidi Löhr
- Experimental and Clinical Pharmacology and Toxicology, Center for Molecular Signaling (PZMS), Saarland University, Buildings 61.4 and 46, 66421 Homburg, Germany; (C.F.-T.); (K.W.); (C.W.); (H.L.); (D.S.K.); (P.W.); (M.W.)
| | - Daniel S. Klawitter
- Experimental and Clinical Pharmacology and Toxicology, Center for Molecular Signaling (PZMS), Saarland University, Buildings 61.4 and 46, 66421 Homburg, Germany; (C.F.-T.); (K.W.); (C.W.); (H.L.); (D.S.K.); (P.W.); (M.W.)
| | - Petra Weissgerber
- Experimental and Clinical Pharmacology and Toxicology, Center for Molecular Signaling (PZMS), Saarland University, Buildings 61.4 and 46, 66421 Homburg, Germany; (C.F.-T.); (K.W.); (C.W.); (H.L.); (D.S.K.); (P.W.); (M.W.)
- Transgenic Technologies, Center for Molecular Signaling (PZMS), Saarland University, Building 61.4, 66421 Homburg, Germany
| | - Elise Gradhand
- Kinder- und Perinatalpathologie Dr. Senckenberg, Institut für Pathologie Universitätsklinikum Frankfurt/Main Theodor-Stern-Kai 7, 60590 Frankfurt, Germany;
| | - Christine P. Burren
- Department of Translational Health Sciences, Bristol Medical School, University of Bristol, University Hospitals Bristol and Weston NHS Foundation Trust, Upper Maudlin St, Bristol BS2 8BJ, UK;
| | - Anna E. Mason
- Histopathology Department, Aneurin Bevan University Health Board, Royal Gwent Hospital, Cardiff NP20 2UB, UK;
| | - Manuel Winter
- Experimental and Clinical Pharmacology and Toxicology, Center for Molecular Signaling (PZMS), Saarland University, Buildings 61.4 and 46, 66421 Homburg, Germany; (C.F.-T.); (K.W.); (C.W.); (H.L.); (D.S.K.); (P.W.); (M.W.)
| | - Ulrich Wissenbach
- Experimental and Clinical Pharmacology and Toxicology, Center for Molecular Signaling (PZMS), Saarland University, Buildings 61.4 and 46, 66421 Homburg, Germany; (C.F.-T.); (K.W.); (C.W.); (H.L.); (D.S.K.); (P.W.); (M.W.)
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15
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Braun JL, Teng ACT, Geromella MS, Ryan CR, Fenech RK, MacPherson REK, Gramolini AO, Fajardo VA. Neuronatin promotes SERCA uncoupling and its expression is altered in skeletal muscles of high-fat diet-fed mice. FEBS Lett 2021; 595:2756-2767. [PMID: 34693525 DOI: 10.1002/1873-3468.14213] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [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: 06/26/2021] [Revised: 10/07/2021] [Accepted: 10/15/2021] [Indexed: 11/09/2022]
Abstract
Neuronatin (NNAT) is a transmembrane protein in the endoplasmic reticulum involved in metabolic regulation. It shares sequence homology with sarcolipin (SLN), which negatively regulates the sarco(endo)plasmic reticulum Ca2+ -ATPase (SERCA) that maintains energy homeostasis in muscles. Here, we examined whether NNAT could uncouple the Ca2+ transport activity of SERCA from ATP hydrolysis, similarly to SLN. NNAT significantly reduced Ca2+ uptake without altering SERCA activity, ultimately lowering the apparent coupling ratio of SERCA. This effect of NNAT was reversed by the adenylyl cyclase activator forskolin. Furthermore, soleus muscles from high fat diet (HFD)-fed mice showed a significant downregulation in NNAT content compared with chow-fed mice, whereas an upregulation in NNAT content was observed in fast-twitch muscles from HFD- versus chow- fed mice. Therefore, NNAT is a SERCA uncoupler in cells and may function in adaptive thermogenesis.
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Affiliation(s)
- Jessica L Braun
- Department of Kinesiology, Brock University, St. Catharines, Canada.,Centre for Bone and Muscle Health, Brock University, St. Catharines, Canada.,Centre for Neuroscience, Brock University, St. Catharines, Canada
| | - Allen C T Teng
- Department of Physiology, University of Toronto, Canada.,Translational Biology and Engineering Program, Ted Rogers Centre for Heart Research, Toronto, Canada
| | - Mia S Geromella
- Department of Kinesiology, Brock University, St. Catharines, Canada.,Centre for Bone and Muscle Health, Brock University, St. Catharines, Canada.,Centre for Neuroscience, Brock University, St. Catharines, Canada
| | - Chantal R Ryan
- Centre for Neuroscience, Brock University, St. Catharines, Canada.,Department of Health Sciences, Brock University, St. Catharines, Canada
| | - Rachel K Fenech
- Centre for Neuroscience, Brock University, St. Catharines, Canada.,Department of Health Sciences, Brock University, St. Catharines, Canada
| | - Rebecca E K MacPherson
- Centre for Neuroscience, Brock University, St. Catharines, Canada.,Department of Health Sciences, Brock University, St. Catharines, Canada
| | - Anthony O Gramolini
- Department of Physiology, University of Toronto, Canada.,Translational Biology and Engineering Program, Ted Rogers Centre for Heart Research, Toronto, Canada
| | - Val A Fajardo
- Department of Kinesiology, Brock University, St. Catharines, Canada.,Centre for Bone and Muscle Health, Brock University, St. Catharines, Canada.,Centre for Neuroscience, Brock University, St. Catharines, Canada
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16
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Corradi GR, Mazzitelli LR, Petrovich GD, de Tezanos Pinto F, Rochi L, Adamo HP. Plasma Membrane Ca 2+ Pump PMCA4z Is More Active Than Splicing Variant PMCA4x. Front Cell Neurosci 2021; 15:668371. [PMID: 34512262 PMCID: PMC8428515 DOI: 10.3389/fncel.2021.668371] [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: 02/16/2021] [Accepted: 07/22/2021] [Indexed: 11/13/2022] Open
Abstract
The plasma membrane Ca2+ pumps (PMCA) are P-ATPases that control Ca2+ signaling and homeostasis by transporting Ca2+ out of the eukaryotic cell. Humans have four genes that code for PMCA isoforms (PMCA1-4). A large diversity of PMCA isoforms is generated by alternative mRNA splicing at sites A and C. The different PMCA isoforms are expressed in a cell-type and developmental-specific manner and exhibit differential sensitivity to a great number of regulatory mechanisms. PMCA4 has two A splice variants, the forms "x" and "z". While PMCA4x is ubiquitously expressed and relatively well-studied, PMCA4z is less characterized and its expression is restricted to some tissues such as the brain and heart muscle. PMCA4z lacks a stretch of 12 amino acids in the so-called A-M3 linker, a conformation-sensitive region of the molecule connecting the actuator domain (A) with the third transmembrane segment (M3). We expressed in yeast PMCA4 variants "x" and "z", maintaining constant the most frequent splice variant "b" at the C-terminal end, and obtained purified preparations of both proteins. In the basal autoinhibited state, PMCA4zb showed a higher ATPase activity and a higher apparent Ca2+ affinity than PMCA4xb. Both isoforms were stimulated by calmodulin but PMCA4zb was more strongly activated by acidic lipids than PMCA4xb. The results indicate that a PMCA4 intrinsically more active and more responsive to acidic lipids is produced by the variant "z" of the splicing site A.
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Affiliation(s)
- Gerardo R Corradi
- Departamento de Química Biológica, Instituto de Química y Fisicoquímica Biológicas, Facultad de Farmacia y Bioquímica, Consejo Nacional de Investigaciones Científicas y Técnicas-Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Luciana R Mazzitelli
- Departamento de Química Biológica, Instituto de Química y Fisicoquímica Biológicas, Facultad de Farmacia y Bioquímica, Consejo Nacional de Investigaciones Científicas y Técnicas-Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Guido D Petrovich
- Departamento de Química Biológica, Instituto de Química y Fisicoquímica Biológicas, Facultad de Farmacia y Bioquímica, Consejo Nacional de Investigaciones Científicas y Técnicas-Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Felicitas de Tezanos Pinto
- Departamento de Química Biológica, Instituto de Química y Fisicoquímica Biológicas, Facultad de Farmacia y Bioquímica, Consejo Nacional de Investigaciones Científicas y Técnicas-Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Lucia Rochi
- Departamento de Química Biológica, Instituto de Química y Fisicoquímica Biológicas, Facultad de Farmacia y Bioquímica, Consejo Nacional de Investigaciones Científicas y Técnicas-Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Hugo P Adamo
- Departamento de Química Biológica, Instituto de Química y Fisicoquímica Biológicas, Facultad de Farmacia y Bioquímica, Consejo Nacional de Investigaciones Científicas y Técnicas-Universidad de Buenos Aires, Buenos Aires, Argentina
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17
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Rathod N, Bak JJ, Primeau JO, Fisher ME, Espinoza-Fonseca LM, Lemieux MJ, Young HS. Nothing Regular about the Regulins: Distinct Functional Properties of SERCA Transmembrane Peptide Regulatory Subunits. Int J Mol Sci 2021; 22:8891. [PMID: 34445594 DOI: 10.3390/ijms22168891] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [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: 07/22/2021] [Revised: 08/10/2021] [Accepted: 08/12/2021] [Indexed: 12/11/2022] Open
Abstract
The sarco-endoplasmic reticulum calcium ATPase (SERCA) is responsible for maintaining calcium homeostasis in all eukaryotic cells by actively transporting calcium from the cytosol into the sarco-endoplasmic reticulum (SR/ER) lumen. Calcium is an important signaling ion, and the activity of SERCA is critical for a variety of cellular processes such as muscle contraction, neuronal activity, and energy metabolism. SERCA is regulated by several small transmembrane peptide subunits that are collectively known as the “regulins”. Phospholamban (PLN) and sarcolipin (SLN) are the original and most extensively studied members of the regulin family. PLN and SLN inhibit the calcium transport properties of SERCA and they are required for the proper functioning of cardiac and skeletal muscles, respectively. Myoregulin (MLN), dwarf open reading frame (DWORF), endoregulin (ELN), and another-regulin (ALN) are newly discovered tissue-specific regulators of SERCA. Herein, we compare the functional properties of the regulin family of SERCA transmembrane peptide subunits and consider their regulatory mechanisms in the context of the physiological and pathophysiological roles of these peptides. We present new functional data for human MLN, ELN, and ALN, demonstrating that they are inhibitors of SERCA with distinct functional consequences. Molecular modeling and molecular dynamics simulations of SERCA in complex with the transmembrane domains of MLN and ALN provide insights into how differential binding to the so-called inhibitory groove of SERCA—formed by transmembrane helices M2, M6, and M9—can result in distinct functional outcomes.
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18
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Tan RSG, Lee CHL, Dimke H, Todd Alexander R. The role of calcium-sensing receptor signaling in regulating transepithelial calcium transport. Exp Biol Med (Maywood) 2021; 246:2407-2419. [PMID: 33926258 DOI: 10.1177/15353702211010415] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [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: 01/01/2023] Open
Abstract
The calcium-sensing receptor (CaSR) plays a critical role in sensing extracellular calcium (Ca2+) and signaling to maintain Ca2+ homeostasis. In the parathyroid, the CaSR regulates secretion of parathyroid hormone, which functions to increase extracellular Ca2+ levels. The CaSR is also located in other organs imperative to Ca2+ homeostasis including the kidney and intestine, where it modulates Ca2+ reabsorption and absorption, respectively. In this review, we describe CaSR expression and its function in transepithelial Ca2+ transport in the kidney and intestine. Activation of the CaSR leads to G protein dependent and independent signaling cascades. The known CaSR signal transduction pathways involved in modulating paracellular and transcellular epithelial Ca2+ transport are discussed. Mutations in the CaSR cause a range of diseases that manifest in altered serum Ca2+ levels. Gain-of-function mutations in the CaSR result in autosomal dominant hypocalcemia type 1, while loss-of-function mutations cause familial hypocalciuric hypercalcemia. Additionally, the putative serine protease, FAM111A, is discussed as a potential regulator of the CaSR because mutations in FAM111A cause Kenny Caffey syndrome type 2, gracile bone dysplasia, and osteocraniostenosis, diseases that are characterized by hypocalcemia, hypoparathyroidism, and bony abnormalities, i.e. share phenotypic features of autosomal dominant hypocalcemia. Recent work has helped to elucidate the effect of CaSR signaling cascades on downstream proteins involved in Ca2+ transport across renal and intestinal epithelia; however, much remains to be discovered.
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Affiliation(s)
- Rebecca Siu Ga Tan
- Department of Physiology, University of Alberta, Edmonton T6G 1C9, Canada.,Membrane Protein Disease Research Group, University of Alberta, Edmonton T6G 1C9, Canada
| | | | - Henrik Dimke
- Department of Cardiovascular and Renal Research, Institute of Molecular Medicine, University of Southern Denmark, Odense 5000, Denmark.,Department of Nephrology, Odense University Hospital, Odense 5000, Denmark
| | - R Todd Alexander
- Department of Physiology, University of Alberta, Edmonton T6G 1C9, Canada.,Membrane Protein Disease Research Group, University of Alberta, Edmonton T6G 1C9, Canada.,Department of Pediatrics, University of Alberta, Edmonton T6G 1C9, Canada
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19
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Peled-Zehavi H, Gal A. Exploring Intracellular Ion Pools in Coccolithophores Using Live-Cell Imaging. Adv Biol (Weinh) 2021; 5:e2000296. [PMID: 33852773 DOI: 10.1002/adbi.202000296] [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] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2020] [Revised: 02/08/2021] [Indexed: 11/06/2022]
Abstract
Some microorganisms, such as coccolithophores, produce an intricate exoskeleton made of inorganic solids. Coccoliths, the calcium carbonate scales of coccolithophores, are examples of the precise bioproduction of such complex 3D structures. However, the understanding of the cellular mechanisms that control mineral formation inside the cell, specifically the ability of these microalgae to transport high fluxes of inorganic building blocks, is still limited. Recently, using cryo-electron and X-ray microscopy, several intracellular compartments are shown to store high concentrations of calcium and phosphorous and are suggested to have a dominant role in the intracellular mineralization pathway. Here, live-cell confocal microscopy and fluorescent markers are used to examine the dynamics of ion stores in coccolithophores. Using calcein and 4',6-diamidino-2-phenylindole (DAPI) as fluorescent proxies for calcium and polyphosphates, the experiments reveal an unexpected plethora of organelles with distinct fluorescent signatures over a wide range of strains and conditions. Surprisingly, the fluorescent labeling does not show changes along the calcification process and is similar between calcifying and noncalcifying cells, suggesting that these ion pools may not be a dynamic avenue for calcium transport. In such a case, the enigma behind the ability of coccolithophores to sustain intracellular calcification still awaits comprehensive elucidation.
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Affiliation(s)
- Hadas Peled-Zehavi
- Department of Plant and Environmental Sciences, Weizmann Institute of Science, Rehovot, 76100, Israel
| | - Assaf Gal
- Department of Plant and Environmental Sciences, Weizmann Institute of Science, Rehovot, 76100, Israel
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20
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Uchida Y, Yamamoto Y, Sakisaka T. Trans-2-enoyl-CoA reductase limits Ca 2+ accumulation in the endoplasmic reticulum by inhibiting the Ca 2+ pump SERCA2b. J Biol Chem 2021; 296:100310. [PMID: 33482198 PMCID: PMC7949109 DOI: 10.1016/j.jbc.2021.100310] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2020] [Revised: 01/04/2021] [Accepted: 01/14/2021] [Indexed: 12/30/2022] Open
Abstract
The endoplasmic reticulum (ER) contains various enzymes that metabolize fatty acids (FAs). Given that FAs are the components of membranes, FA metabolic enzymes might be associated with regulation of ER membrane functions. However, it remains unclear whether there is the interplay between FA metabolic enzymes and ER membrane proteins. Trans-2-enoyl-CoA reductase (TER) is an FA reductase present in the ER membrane and catalyzes the last step in the FA elongation cycle and sphingosine degradation pathway. Here we identify sarco(endo)plasmic reticulum Ca2+-ATPase 2b (SERCA2b), an ER Ca2+ pump responsible for Ca2+ accumulation in the ER, as a TER-binding protein by affinity purification from HEK293 cell lysates. We show that TER directly binds to SERCA2b by in vitro assays using recombinant proteins. Thapsigargin, a specific SERCA inhibitor, inhibits this binding. TER binds to SERCA2b through its conserved C-terminal region. TER overexpression suppresses SERCA2b ATPase activity in microsomal membranes of HEK293 cells. Depletion of TER increases Ca2+ storage in the ER and accelerates SERCA2b-dependent Ca2+ uptake to the ER after ligand-induced Ca2+ release. Moreover, depletion of TER reduces the Ca2+-dependent nuclear translocation of nuclear factor of activated T cells 4. These results demonstrate that TER is a negative regulator of SERCA2b, implying the direct linkage of FA metabolism and Ca2+ accumulation in the ER.
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Affiliation(s)
- Yasunori Uchida
- Division of Membrane Dynamics, Department of Physiology and Cell Biology, Kobe University School of Medicine, Kobe, Japan
| | - Yasunori Yamamoto
- Division of Membrane Dynamics, Department of Physiology and Cell Biology, Kobe University School of Medicine, Kobe, Japan
| | - Toshiaki Sakisaka
- Division of Membrane Dynamics, Department of Physiology and Cell Biology, Kobe University School of Medicine, Kobe, Japan.
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21
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Thibodeau S, Yang W, Sharma S, Lytton J. Calmodulin binds and modulates K +-dependent Na +/Ca 2+-exchanger isoform 4, NCKX4. J Biol Chem 2021; 296:100092. [PMID: 33199372 PMCID: PMC7949085 DOI: 10.1074/jbc.ra120.015037] [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] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2020] [Revised: 10/25/2020] [Accepted: 11/16/2020] [Indexed: 11/06/2022] Open
Abstract
The family of K+-dependent Na+/Ca2+-exchangers, NCKX, are important mediators of cellular Ca2+ efflux, particularly in neurons associated with sensory transduction. The NCKX family comprises five proteins, NCKX1-5, each being the product of a different SLC24 gene. NCKX4 (SLC24A4) has been found to have a critical role in termination and adaptation of visual and olfactory signals, melanocortin-dependent satiety signaling, and the maturation of dental enamel. To explore mechanisms that might influence the temporal control of NCKX4 activity, a yeast two-hybrid system was used to search for protein interaction partners. We identified calmodulin as a partner for NCKX4 and confirmed the interaction using glutathione-S-transferase fusion pull-down. Calmodulin binding to NCKX4 was demonstrated in extracts from mouse brain and in transfected HEK293 cells. Calmodulin bound in a Ca2+-dependent manner to a motif present in the central cytosolic loop of NCKX4 and was abolished by the double-mutant I328D/F334D. When cotransfected in HEK293 cells, calmodulin bound to NCKX4 under basal conditions and induced a ∼2.5-fold increase in NCKX4 abundance, but did not influence either cellular location or basal activity. When purinergic stimulation of NCKX4 was examined in these cells, coexpression of wild-type calmodulin, but not a Ca2+ binding-deficient calmodulin mutant, suppressed NCKX4 activation in a time-dependent manner. We propose that Ca2+ binding to calmodulin prepositioned on NCKX4 induces a slow conformational rearrangement that interferes with purinergic stimulation of the exchanger, possibly by obscuring T331, a previously identified potential protein kinase C site.
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Affiliation(s)
- Stephanie Thibodeau
- Department of Biochemistry & Molecular Biology, Libin Cardiovascular Institute and Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Weidong Yang
- Department of Biochemistry & Molecular Biology, Libin Cardiovascular Institute and Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Sunita Sharma
- Department of Biochemistry & Molecular Biology, Libin Cardiovascular Institute and Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Jonathan Lytton
- Department of Biochemistry & Molecular Biology, Libin Cardiovascular Institute and Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada.
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22
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Abstract
Calcium is a key ion involved in cardiac and skeletal muscle contractility, nerve function, and skeletal structure. Global calcium balance is affected by parathyroid hormone and vitamin D, and calcium is shuttled between the extracellular space and the bone matrix compartment dynamically. The kidney plays an important role in whole-body calcium balance. Abnormalities in the kidney transport proteins alter the renal excretion of calcium. Various hormonal and regulatory pathways have evolved that regulate the renal handling of calcium to maintain the serum calcium within defined limits despite dynamic changes in dietary calcium intake. Dysregulation of renal calcium transport can occur pharmacologically, hormonally, and via genetic mutations in key proteins in various nephron segments resulting in several disease processes. This review focuses on the regulation transport of calcium in the nephron. Genetic diseases affecting the renal handling of calcium that can potentially lead to changes in the serum calcium concentration are reviewed.
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Affiliation(s)
- Ramy M. Hanna
- Division of Nephrology, Department of Medicine, University of California Irvine (UCI) School of Medicine, Orange, CA, United States
- *Correspondence: Ramy M. Hanna,
| | - Rebecca S. Ahdoot
- Division of Nephrology, Department of Medicine, University of California Irvine (UCI) School of Medicine, Orange, CA, United States
| | - Kamyar Kalantar-Zadeh
- Division of Nephrology, Department of Medicine, University of California Irvine (UCI) School of Medicine, Orange, CA, United States
| | - Lena Ghobry
- School of Public Health, University of Pittsburgh, Pittsburgh, PA, United States
| | - Ira Kurtz
- Division of Nephrology, Department of Medicine, David Geffen School of Medicine, University of California Los Angeles (UCLA), Los Angeles, CA, United States
- University of California Los Angeles (UCLA) Brain Research Center, Los Angeles, CA, United States
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23
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Anthony SR, Guarnieri A, Lanzillotta L, Gozdiff A, Green LC, O’Grady K, Helsley RN, Owens AP, Tranter M. HuR expression in adipose tissue mediates energy expenditure and acute thermogenesis independent of UCP1 expression. Adipocyte 2020; 9:335-345. [PMID: 32713230 PMCID: PMC7469577 DOI: 10.1080/21623945.2020.1782021] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [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] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/07/2020] [Revised: 04/30/2020] [Accepted: 05/07/2020] [Indexed: 11/20/2022] Open
Abstract
The goal of this study was to define the functional role of adipocyte-specific expression of the RNA binding protein Human antigen R (HuR). Mice with an adipocyte-specific deletion of HuR (Adipo-HuR-/- ) were generated by crossing HuR floxed (HuRfl/fl ) mice with mice expressing adiponectin-driven cre-recombinase (Adipoq-cre). Our results show that Adipo-HuR-/- mice display a lean phenotype compared to wild-type littermate controls. HuR deletion results in a diet-independent reduction in percent body fat composition along with an increase in energy expenditure. Functionally, Adipo-HuR-/- mice show a significant impairment in acute adaptive thermogenesis (six hours at 4°C), but uncoupling protein 1 (UCP1) protein expression in brown adipose tissue (BAT) is unchanged compared to control. Pharmacological inhibition of HuR also results in a marked decline in core body temperature following acute cold challenge independent of UCP1 protein expression. Among the 588 HuR-dependent genes in BAT identified by RNA-seq analysis, gene ontology analysis shows a significant enrichment in mediators of calcium transport and signalling, almost all of which are decreased in Adipo-HuR-/- mice compared to control. In conclusion, adipocyte expression of HuR plays a central role in metabolic homoeostasis and mediates UCP1-independent thermogenesis in BAT, potentially through post-transcriptional control of intracellular calcium transport.Abbreviations: Adipo-HuR-/-: Adipocyte-specific HuR deletion mice; BAT: Brown adipose tissue; HuR: Human antigen R; UCP1: Uncoupling protein 1.
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Affiliation(s)
- Sarah R. Anthony
- Department of Internal Medicine, Division of Cardiovascular Health and Disease, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - Adrienne Guarnieri
- Department of Internal Medicine, Division of Cardiovascular Health and Disease, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - Lindsey Lanzillotta
- Department of Internal Medicine, Division of Cardiovascular Health and Disease, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - Anamarie Gozdiff
- Department of Internal Medicine, Division of Cardiovascular Health and Disease, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - Lisa C. Green
- Department of Internal Medicine, Division of Cardiovascular Health and Disease, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - Katherine O’Grady
- Department of Internal Medicine, Division of Cardiovascular Health and Disease, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - Robert N. Helsley
- Division of Pediatrics, Department of Gastroenterology, Hepatology, and Nutrition, University of Kentucky College of Medicine and Kentucky Children’s Hospital, Lexington, KY, USA
| | - A. Phillip Owens
- Department of Internal Medicine, Division of Cardiovascular Health and Disease, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - Michael Tranter
- Department of Internal Medicine, Division of Cardiovascular Health and Disease, University of Cincinnati College of Medicine, Cincinnati, OH, USA
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24
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Naumova N, Šachl R. Regulation of Cell Death by Mitochondrial Transport Systems of Calcium and Bcl-2 Proteins. Membranes (Basel) 2020; 10:E299. [PMID: 33096926 PMCID: PMC7590060 DOI: 10.3390/membranes10100299] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [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: 08/27/2020] [Revised: 10/16/2020] [Accepted: 10/19/2020] [Indexed: 12/13/2022]
Abstract
Mitochondria represent the fundamental system for cellular energy metabolism, by not only supplying energy in the form of ATP, but also by affecting physiology and cell death via the regulation of calcium homeostasis and the activity of Bcl-2 proteins. A lot of research has recently been devoted to understanding the interplay between Bcl-2 proteins, the regulation of these interactions within the cell, and how these interactions lead to the changes in calcium homeostasis. However, the role of Bcl-2 proteins in the mediation of mitochondrial calcium homeostasis, and therefore the induction of cell death pathways, remain underestimated and are still not well understood. In this review, we first summarize our knowledge about calcium transport systems in mitochondria, which, when miss-regulated, can induce necrosis. We continue by reviewing and analyzing the functions of Bcl-2 proteins in apoptosis. Finally, we link these two regulatory mechanisms together, exploring the interactions between the mitochondrial Ca2+ transport systems and Bcl-2 proteins, both capable of inducing cell death, with the potential to determine the cell death pathway-either the apoptotic or the necrotic one.
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Affiliation(s)
| | - Radek Šachl
- J. Heyrovský Institute of Physical Chemistry, Czech Academy of Sciences, 182 23 Prague, Czech Republic;
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25
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Stapane L, Le Roy N, Ezagal J, Rodriguez-Navarro AB, Labas V, Combes-Soia L, Hincke MT, Gautron J. Avian eggshell formation reveals a new paradigm for vertebrate mineralization via vesicular amorphous calcium carbonate. J Biol Chem 2020; 295:15853-15869. [PMID: 32816992 DOI: 10.1074/jbc.ra120.014542] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [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: 07/20/2020] [Indexed: 12/16/2022] Open
Abstract
Amorphous calcium carbonate (ACC) is an unstable mineral phase, which is progressively transformed into aragonite or calcite in biomineralization of marine invertebrate shells or avian eggshells, respectively. We have previously proposed a model of vesicular transport to provide stabilized ACC in chicken uterine fluid where eggshell mineralization takes place. Herein, we report further experimental support for this model. We confirmed the presence of extracellular vesicles (EVs) using transmission EM and showed high levels of mRNA of vesicular markers in the oviduct segments where eggshell mineralization occurs. We also demonstrate that EVs contain ACC in uterine fluid using spectroscopic analysis. Moreover, proteomics and immunofluorescence confirmed the presence of major vesicular, mineralization-specific and eggshell matrix proteins in the uterus and in purified EVs. We propose a comprehensive role for EVs in eggshell mineralization, in which annexins transfer calcium into vesicles and carbonic anhydrase 4 catalyzes the formation of bicarbonate ions (HCO[Formula: see text]), for accumulation of ACC in vesicles. We hypothesize that ACC is stabilized by ovalbumin and/or lysozyme or additional vesicle proteins identified in this study. Finally, EDIL3 and MFGE8 are proposed to serve as guidance molecules to target EVs to the mineralization site. We therefore report for the first-time experimental evidence for the components of vesicular transport to supply ACC in a vertebrate model of biomineralization.
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Affiliation(s)
| | | | - Jacky Ezagal
- BOA INRAe, Université de Tours, Nouzilly, France
| | | | - Valérie Labas
- Unité Mixte de Recherches Physiologie de la Reproduction et des Comportements, Université de Tours IFCE, Nouzilly, France
| | - Lucie Combes-Soia
- Unité Mixte de Recherches Physiologie de la Reproduction et des Comportements, Université de Tours IFCE, Nouzilly, France
| | - Maxwell T Hincke
- Department of Innovation in Medical Education, and Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, Canada
| | - Joël Gautron
- BOA INRAe, Université de Tours, Nouzilly, France.
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26
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Alford RF, Smolin N, Young HS, Gray JJ, Robia SL. Protein docking and steered molecular dynamics suggest alternative phospholamban-binding sites on the SERCA calcium transporter. J Biol Chem 2020; 295:11262-11274. [PMID: 32554805 DOI: 10.1074/jbc.ra120.012948] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [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: 02/07/2020] [Revised: 06/16/2020] [Indexed: 01/27/2023] Open
Abstract
The transport activity of the sarco(endo)plasmic reticulum calcium ATPase (SERCA) in cardiac myocytes is modulated by an inhibitory interaction with a transmembrane peptide, phospholamban (PLB). Previous biochemical studies have revealed that PLB interacts with a specific inhibitory site on SERCA, and low-resolution structural evidence suggests that PLB interacts with distinct alternative sites on SERCA. High-resolution details of the structural determinants of SERCA regulation have been elusive because of the dynamic nature of the regulatory complex. In this study, we used computational approaches to develop a structural model of SERCA-PLB interactions to gain a mechanistic understanding of PLB-mediated SERCA transport regulation. We combined steered molecular dynamics and membrane protein-protein docking experiments to achieve both a global search and all-atom force calculations to determine the relative affinities of PLB for candidate sites on SERCA. We modeled the binding of PLB to several SERCA conformations, representing different enzymatic states sampled during the calcium transport catalytic cycle. The results of the steered molecular dynamics and docking experiments indicated that the canonical PLB-binding site (comprising transmembrane helices M2, M4, and M9) is the preferred site. This preference was even more stringent for a superinhibitory PLB variant. Interestingly, PLB-binding specificity became more ambivalent for other SERCA conformers. These results provide evidence for polymorphic PLB interactions with novel sites on M3 and with the outside of the SERCA helix M9. Our findings are compatible with previous physical measurements that suggest that PLB interacts with multiple binding sites, conferring dynamic responsiveness to changing physiological conditions.
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Affiliation(s)
- Rebecca F Alford
- Department of Chemical and Biomolecular Engineering, Johns Hopkins University, Baltimore, Maryland, USA
| | - Nikolai Smolin
- Department of Cell and Molecular Physiology, Stritch School of Medicine, Cardiovascular Research Institute, Loyola University Chicago, Maywood, Illinois, USA
| | - Howard S Young
- Department of Biochemistry, University of Alberta, Edmonton, Alberta, Canada
| | - Jeffrey J Gray
- Department of Chemical and Biomolecular Engineering, Johns Hopkins University, Baltimore, Maryland, USA
| | - Seth L Robia
- Department of Cell and Molecular Physiology, Stritch School of Medicine, Cardiovascular Research Institute, Loyola University Chicago, Maywood, Illinois, USA
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27
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Horning KJ, Joshi P, Nitin R, Balachandran RC, Yanko FM, Kim K, Christov P, Aschner M, Sulikowski GA, Weaver CD, Bowman AB. Identification of a selective manganese ionophore that enables nonlethal quantification of cellular manganese. J Biol Chem 2020; 295:3875-3890. [PMID: 32047113 PMCID: PMC7086026 DOI: 10.1074/jbc.ra119.009781] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [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: 07/10/2019] [Revised: 02/11/2020] [Indexed: 01/14/2023] Open
Abstract
Available assays for measuring cellular manganese (Mn) levels require cell lysis, restricting longitudinal experiments and multiplexed outcome measures. Conducting a screen of small molecules known to alter cellular Mn levels, we report here that one of these chemicals induces rapid Mn efflux. We describe this activity and the development and implementation of an assay centered on this small molecule, named manganese-extracting small molecule (MESM). Using inductively-coupled plasma-MS, we validated that this assay, termed here "manganese-extracting small molecule estimation route" (MESMER), can accurately assess Mn in mammalian cells. Furthermore, we found evidence that MESM acts as a Mn-selective ionophore, and we observed that it has increased rates of Mn membrane transport, reduced cytotoxicity, and increased selectivity for Mn over calcium compared with two established Mn ionophores, calcimycin (A23187) and ionomycin. Finally, we applied MESMER to test whether prior Mn exposures subsequently affect cellular Mn levels. We found that cells receiving continuous, elevated extracellular Mn accumulate less Mn than cells receiving equally-elevated Mn for the first time for 24 h, indicating a compensatory cellular homeostatic response. Use of the MESMER assay versus a comparable detergent lysis-based assay, cellular Fura-2 Mn extraction assay, reduced the number of cells and materials required for performing a similar but cell lethality-based experiment to 25% of the normally required sample size. We conclude that MESMER can accurately quantify cellular Mn levels in two independent cells lines through an ionophore-based mechanism, maintaining cell viability and enabling longitudinal assessment within the same cultures.
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Affiliation(s)
- Kyle J. Horning
- Vanderbilt Brain Institute, Vanderbilt University, Nashville, Tennessee 37232
| | - Piyush Joshi
- Vanderbilt Brain Institute, Vanderbilt University, Nashville, Tennessee 37232
| | - Rachana Nitin
- Vanderbilt Brain Institute, Vanderbilt University, Nashville, Tennessee 37232
| | | | - Frank M. Yanko
- School of Health Sciences, Purdue University, West Lafayette, Indiana 47907
| | - Kwangho Kim
- Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, Tennessee 37232,Department of Chemistry, Vanderbilt University, Nashville, Tennessee 37235
| | - Plamen Christov
- Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, Tennessee 37232
| | - Michael Aschner
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, New York 10461
| | - Gary A. Sulikowski
- Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, Tennessee 37232,Department of Chemistry, Vanderbilt University, Nashville, Tennessee 37235,Department of Pharmacology, Vanderbilt University, Nashville, Tennessee 37212
| | - C. David Weaver
- Department of Chemistry, Vanderbilt University, Nashville, Tennessee 37235,Department of Pharmacology, Vanderbilt University, Nashville, Tennessee 37212
| | - Aaron B. Bowman
- Vanderbilt Brain Institute, Vanderbilt University, Nashville, Tennessee 37232,School of Health Sciences, Purdue University, West Lafayette, Indiana 47907, To whom correspondence should be addressed:
Purdue University, 550 Stadium Mall Dr., HAMP 1173A, West Lafayette, IN 47907-2051. E-mail:
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28
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Stribny J, Thines L, Deschamps A, Goffin P, Morsomme P. The human Golgi protein TMEM165 transports calcium and manganese in yeast and bacterial cells. J Biol Chem 2020; 295:3865-3874. [PMID: 32047108 DOI: 10.1074/jbc.ra119.012249] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [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: 12/09/2019] [Revised: 02/10/2020] [Indexed: 01/17/2023] Open
Abstract
Cases of congenital disorders of glycosylation (CDG) have been associated with specific mutations within the gene encoding the human Golgi TMEM165 (transmembrane protein 165), belonging to UPF0016 (uncharacterized protein family 0016), a family of secondary ion transporters. To date, members of this family have been reported to be involved in calcium, manganese, and pH homeostases. Although it has been suggested that TMEM165 has cation transport activity, direct evidence for its Ca2+- and Mn2+-transporting activities is still lacking. Here, we functionally characterized human TMEM165 by heterologously expressing it in budding yeast (Saccharomyces cerevisiae) and in the bacterium Lactococcus lactis Protein production in these two microbial hosts was enhanced by codon optimization and truncation of the putatively autoregulatory N terminus of TMEM165. We show that TMEM165 expression in a yeast strain devoid of Golgi Ca2+ and Mn2+ transporters abrogates Ca2+- and Mn2+-induced growth defects, excessive Mn2+ accumulation in the cell, and glycosylation defects. Using bacterial cells loaded with the fluorescent Fura-2 probe, we further obtained direct biochemical evidence that TMEM165 mediates Ca2+ and Mn2+ influxes. We also used the yeast and bacterial systems to evaluate the impact of four disease-causing missense mutations identified in individuals with TMEM165-associated CDG. We found that a mutation leading to a E108G substitution within the conserved UPF0016 family motif significantly reduces TMEM165 activity. These results indicate that TMEM165 can transport Ca2+ and Mn2+, which are both required for proper protein glycosylation in cells. Our work also provides tools to better understand the pathogenicity of CDG-associated TMEM165 mutations.
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Affiliation(s)
- Jiri Stribny
- Louvain Institute of Biomolecular Science and Technology, Université Catholique de Louvain, B-1348 Louvain-la-Neuve, Belgium
| | - Louise Thines
- Louvain Institute of Biomolecular Science and Technology, Université Catholique de Louvain, B-1348 Louvain-la-Neuve, Belgium
| | - Antoine Deschamps
- Louvain Institute of Biomolecular Science and Technology, Université Catholique de Louvain, B-1348 Louvain-la-Neuve, Belgium
| | - Philippe Goffin
- Cellular and Molecular Microbiology Lab, Université Libre de Bruxelles, B-6041 Gosselies, Belgium
| | - Pierre Morsomme
- Louvain Institute of Biomolecular Science and Technology, Université Catholique de Louvain, B-1348 Louvain-la-Neuve, Belgium
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29
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Rodríguez Y, Májeková M. Structural Changes of Sarco/Endoplasmic Reticulum Ca 2+-ATPase Induced by Rutin Arachidonate: A Molecular Dynamics Study. Biomolecules 2020; 10:biom10020214. [PMID: 32024167 PMCID: PMC7072167 DOI: 10.3390/biom10020214] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [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: 12/08/2019] [Revised: 01/15/2020] [Accepted: 01/28/2020] [Indexed: 11/16/2022] Open
Abstract
Sarco/endoplasmic reticulum Ca2+-ATPase (SERCA) maintains the level of calcium concentration in cells by pumping calcium ions from the cytoplasm to the lumen while undergoing substantial conformational changes, which can be stabilized or prevented by various compounds. Here we attempted to clarify the molecular mechanism of action of new inhibitor rutin arachidonate, one of the series of the acylated rutin derivatives. We performed molecular dynamics simulations of SERCA1a protein bound to rutin arachidonate positioned in a pure dipalmitoylphosphatidylcholine bilayer membrane. Our study predicted the molecular basis for the binding of rutin arachidonate towards SERCA1a in the vicinity of the binding site of calcium ions and near the location of the well-known inhibitor thapsigargin. The stable hydrogen bond between Glu771 and rutin arachidonate plays a key role in the binding. SERCA1a is kept in the E2 conformation preventing the formation of important salt bridges between the side chains of several residues, primarily Glu90 and Lys297. All in all, the structural changes induced by the binding of rutin arachidonate to SERCA1a may shift proton balance near the titrable residues Glu771 and Glu309 into neutral species, hence preventing the binding of calcium ions to the transmembrane binding sites and thus affecting calcium homeostasis. Our results could lead towards the design of new types of inhibitors, potential drug candidates for cancer treatment, which could be anchored to the transmembrane region of SERCA1a by a lipophilic fatty acid group.
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Affiliation(s)
- Yoel Rodríguez
- Department of Natural Sciences, Eugenio María de Hostos Community College of The City University of New York, 500 Grand Concourse, Bronx, New York, NY 10451, USA; or
- Department of Pharmacological Sciences, Icahn School of Medicine at Mount Sinai, 1425 Madison Avenue, New York, NY 10029, USA
| | - Magdaléna Májeková
- Center of Experimental Medicine of Slovak Academy of Sciences, Institute of Experimental Pharmacology and Toxicology, Department of Biochemical Pharmacology, Dubravska cesta 9, 841 04 Bratislava, Slovakia
- Correspondence: ; Tel.: +421-2-3229-5709
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30
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Abstract
Calcium oxalate (CaOx) crystals occur as intravacuolar deposits in most angiosperm species. Different functions have been attributed to these crystals, some of which are very speculative, until now. Calcium regulation and homeostasis seem to be the most widespread function of CaOx crystals. Being rich in calcium, these crystals constitute a reserve of calcium for plants. However, despite being bioavailable, this reserve is functional in just a few situations due to the low mobility of calcium for phloem translocation. Therefore, CaOx crystals as a calcium reserve is a paradox because in most cases the reserve cannot be used. However, in most plants, these crystals occur in organs or tissues that will be discarded, which allows the elimination of excess calcium. This suggests that CaOx crystals have a functional role in excess calcium excretion. There is some evidence that, for calcium, this excretory function is relevant for plants since they lack an excretory system dedicated to discarding solid wastes, such as calcium salts.
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Affiliation(s)
- Elder Antônio Sousa Paiva
- Plant Secretion & Reproduction (PlantSeR) Lab, Departamento de Botânica, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, 31270-901, Belo Horizonte, Minas Gerais, Brazil
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31
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Stapane L, Le Roy N, Hincke MT, Gautron J. The glycoproteins EDIL3 and MFGE8 regulate vesicle-mediated eggshell calcification in a new model for avian biomineralization. J Biol Chem 2019; 294:14526-14545. [PMID: 31358619 DOI: 10.1074/jbc.ra119.009799] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [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: 06/14/2019] [Revised: 07/26/2019] [Indexed: 11/06/2022] Open
Abstract
The avian eggshell is a critical physical barrier, which permits extra-uterine development of the embryo. Its formation involves the fastest known biomineralization process in vertebrates. The eggshell consists of proteins and proteoglycans that interact with the mineral phase to impart its specific microstructure and mechanical properties. In this study, we investigated the role of epidermal growth factor (EGF)-like repeats and discoidin-like domains 3 (EDIL3) and milk fat globule-EGF factor 8 (MFGE8), two glycoproteins that are consistently detected in eggshell proteomes. We verified their common evolutionary history and identified the timing of the duplication event giving rise to these two distinct proteins. Edil3/mfge8 chromosomal locations revealed a nested syntenous relationship with other genes (hapln1/hapln3 and vcan/acan) that are also involved in vertebrate calcification. EDIL3 and MFGE8 proteins possess EGF-like and coagulation factor 5/8 (F5/8C) domains, and their 3D structures predicted that they bind calcium and extracellular vesicles. In chicken, we confirmed the presence of EDIL3 and MFGE8 proteins in eggshell, uterine fluid, and uterus. We observed that only edil3 is overexpressed in tissues in which eggshell mineralization takes place and that this overexpression occurs only at the onset of shell calcification. We therefore propose a model in which EDIL3 and, to a lesser extent, MFGE8 proteins guide vesicles containing amorphous calcium carbonate to the mineralization site. This model was supported by the observation that extracellular vesicles accumulate in uterine fluid during eggshell calcification and that they contain high levels of calcium, carbon, and oxygen that correspond to calcium carbonate.
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Affiliation(s)
| | | | - Maxwell T Hincke
- Department of Innovation in Medical Education, Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa K1H 8M5, Canada
| | - Joël Gautron
- BOA, INRA, Université de Tours, 37380 Nouzilly, France
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32
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Liang X, Samways DSK, Cox J, Egan TM. Ca 2+ flux through splice variants of the ATP-gated ionotropic receptor P2X7 is regulated by its cytoplasmic N terminus. J Biol Chem 2019; 294:12521-12533. [PMID: 31248985 DOI: 10.1074/jbc.ra119.009666] [Citation(s) in RCA: 10] [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] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2019] [Revised: 06/26/2019] [Indexed: 01/12/2023] Open
Abstract
Activation of ionotropic P2X receptors increases free intracellular Ca2+ ([Ca2+] i ) by initiating a transmembrane cation flux. We studied the "a" and "k" splice variants of the rat purinergic P2X7 receptor (rP2X7aR and rP2X7kR) to exhibit a significant difference in Ca2+ flux through this channel. This difference is surprising because the variants share absolute sequence identity in the area of the pore that defines ionic selectivity. Here, we used patch-clamp fluorometry and chimeric receptors to show that the fraction of the total current carried by Ca2+ is a function of the primary sequence of the cytoplasmic N terminus. Using scanning mutagenesis, we identified five sites within the N terminus that respond to mutagenesis with a decrease in fractional calcium current and an increase in permeability to the polyatomic cation, N-methyl-d-glucamine (NMDG+), relative to Na+ (P NMDG/P Na). We tested the hypothesis that these sites line the permeation pathway by measuring the ability of thiol-reactive MTSET+ to alter the current of cysteine-substituted variants, but we detected no effect. Finally, we studied the homologous sites of the rat P2X2 receptor (rP2X2R) and observed that substitutions at Glu17 significantly reduced the fractional calcium current. Taken together, our results suggest that a change in the structure of the N terminus alters the ability of an intra-pore Ca2+ selectivity filter to discriminate among permeating cations. These results are noteworthy for two reasons: they identify a previously unknown outcome of mutagenesis of the N-terminal domain, and they suggest caution when assigning structure to function for truncated P2X receptors that lack a part of the N terminus.
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Affiliation(s)
- Xin Liang
- School of Pharmaceutical Sciences (Shenzhen), Sun Yat-Sen University, Guangzhou 510275, China
| | | | - Jane Cox
- Department of Pharmacology and Physiology and The Henry and Amelia Nasrallah Center for Neuroscience, Saint Louis University School of Medicine, St. Louis, Missouri 63104
| | - Terrance M Egan
- Department of Pharmacology and Physiology and The Henry and Amelia Nasrallah Center for Neuroscience, Saint Louis University School of Medicine, St. Louis, Missouri 63104.
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Zoppoli P, Calice G, Laurino S, Ruggieri V, La Rocca F, La Torre G, Ciuffi M, Amendola E, De Vita F, Petrillo A, Napolitano G, Falco G, Russi S. TRPV2 Calcium Channel Gene Expression and Outcomes in Gastric Cancer Patients: A Clinically Relevant Association. J Clin Med 2019; 8:E662. [PMID: 31083561 PMCID: PMC6572141 DOI: 10.3390/jcm8050662] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [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: 04/16/2019] [Revised: 05/07/2019] [Accepted: 05/08/2019] [Indexed: 02/06/2023] Open
Abstract
Gastric cancer (GC) is characterized by poor efficacy and the modest clinical impact of current therapies. Apoptosis evasion represents a causative factor for treatment failure in GC as in other cancers. Since intracellular calcium homeostasis regulation has been found to be associated with apoptosis resistance, the aberrant expression of intracellular calcium regulator genes (CaRGs) could have a prognostic value in GC patients. We analyzed the association of the expression levels of 98 CaRGs with prognosis by the log-rank test in a collection of 1524 GC samples from four gene expression profiling datasets. We also evaluated differential gene expression in comparison with normal stomach tissue, and then we crossed results with tissue microarrays from the Human Protein Atlas. Among the investigated CaRGs, patients with high levels of TRPV2 expression were characterized by a shorter overall survival. TRPV2 expression was found to increase according to tumor stage. Both mRNA and protein levels were significantly higher in tumor than normal stomach samples. TRPV2 was also associated with poor prognosis in the Lauren's intestinal type GC and in patients treated with adjuvant therapy. Overall, we highlighted the relevance of TRPV2 not only as a prognostic biomarker but also as a potential therapeutic target to improve GC treatment efficacy.
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Affiliation(s)
- Pietro Zoppoli
- Laboratory of Preclinical and Translational Research, IRCCS-Referral Cancer Center of Basilicata (CROB), 85028 Rionero in Vulture (PZ), Italy.
| | - Giovanni Calice
- Laboratory of Preclinical and Translational Research, IRCCS-Referral Cancer Center of Basilicata (CROB), 85028 Rionero in Vulture (PZ), Italy.
| | - Simona Laurino
- Laboratory of Preclinical and Translational Research, IRCCS-Referral Cancer Center of Basilicata (CROB), 85028 Rionero in Vulture (PZ), Italy.
| | - Vitalba Ruggieri
- Laboratory of Preclinical and Translational Research, IRCCS-Referral Cancer Center of Basilicata (CROB), 85028 Rionero in Vulture (PZ), Italy.
| | - Francesco La Rocca
- Laboratory of Preclinical and Translational Research, IRCCS-Referral Cancer Center of Basilicata (CROB), 85028 Rionero in Vulture (PZ), Italy.
| | - Giuseppe La Torre
- Laboratory of Preclinical and Translational Research, IRCCS-Referral Cancer Center of Basilicata (CROB), 85028 Rionero in Vulture (PZ), Italy.
| | - Mario Ciuffi
- Laboratory of Preclinical and Translational Research, IRCCS-Referral Cancer Center of Basilicata (CROB), 85028 Rionero in Vulture (PZ), Italy.
| | - Elena Amendola
- Department of Biology, University of Naples Federico II, 80138 Naples, Italy.
| | - Ferdinando De Vita
- Division of Medical Oncology, Department of Precision Medicine, School of Medicine, University of Study of Campania "Luigi Vanvitelli", 80138 Naples, Italy.
| | - Angelica Petrillo
- Division of Medical Oncology, Department of Precision Medicine, School of Medicine, University of Study of Campania "Luigi Vanvitelli", 80138 Naples, Italy.
| | - Giuliana Napolitano
- Department of Biology, University of Naples Federico II, 80138 Naples, Italy.
| | - Geppino Falco
- Department of Biology, University of Naples Federico II, 80138 Naples, Italy.
- Biogem, Istituto di Biologia e Genetica Molecolare, Via Camporeale, 83031 Ariano Irpino (AV), Italy.
| | - Sabino Russi
- Laboratory of Preclinical and Translational Research, IRCCS-Referral Cancer Center of Basilicata (CROB), 85028 Rionero in Vulture (PZ), Italy.
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Chen J, Smaardijk S, Mattelaer CA, Pamula F, Vandecaetsbeek I, Vanoevelen J, Wuytack F, Lescrinier E, Eggermont J, Vangheluwe P. An N-terminal Ca 2+-binding motif regulates the secretory pathway Ca 2+/Mn 2+-transport ATPase SPCA1. J Biol Chem 2019; 294:7878-7891. [PMID: 30923126 DOI: 10.1074/jbc.ra118.006250] [Citation(s) in RCA: 10] [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] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2018] [Revised: 03/23/2019] [Indexed: 11/06/2022] Open
Abstract
The Ca2+/Mn2+ transport ATPases 1a and 2 (SPCA1a/2) are closely related to the sarco(endo)plasmic reticulum Ca2+-ATPase (SERCA) and are implicated in breast cancer and Hailey-Hailey skin disease. Here, we purified the human SPCA1a/2 isoforms from a yeast recombinant expression system and compared their biochemical properties after reconstitution. We observed that the purified SPCA1a displays a lower Ca2+ affinity and slightly lower Mn2+ affinity than SPCA2. Remarkably, the turnover rates of SPCA1a in the presence of Mn2+ and SPCA2 incubated with Ca2+ and Mn2+ were comparable, whereas the turnover rate of SPCA1a in Ca2+ was 2-fold higher. Moreover, we noted an unusual biphasic activation curve for the SPCA1a ATPase and autophosphorylation activity, not observed with SPCA2. We also found that the biphasic pattern and low apparent ion affinity of SPCA1a critically depends on ATP concentration. We further show that the specific properties of SPCA1a at least partially depend on an N-terminal EF-hand-like motif, which is present only in the SPCA1a isoform and absent in SPCA2. This motif binds Ca2+, and its mutation lowered the Ca2+ turnover rate relative to that of Mn2+, increased substrate affinity, and reduced the level of biphasic activation of SPCA1a. A biochemical analysis indicated that Ca2+ binding to the N-terminal EF-hand-like motif promotes the activity of SPCA1a by facilitating autophosphorylation. We propose that this regulation may be physiologically relevant in cells with a high Ca2+ load, such as mammary gland cells during lactation, or in cells with a low ATP content, such as keratinocytes.
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Affiliation(s)
- Jialin Chen
- From the Laboratory of Cellular Transport Systems, Department of Cellular and Molecular Medicine and
| | - Susanne Smaardijk
- From the Laboratory of Cellular Transport Systems, Department of Cellular and Molecular Medicine and
| | - Charles-Alexandre Mattelaer
- Medicinal Chemistry, Department of Pharmaceutical and Pharmacological Sciences, Rega Institute, KU Leuven, Belgium
| | - Filip Pamula
- From the Laboratory of Cellular Transport Systems, Department of Cellular and Molecular Medicine and
| | - Ilse Vandecaetsbeek
- From the Laboratory of Cellular Transport Systems, Department of Cellular and Molecular Medicine and
| | - Jo Vanoevelen
- From the Laboratory of Cellular Transport Systems, Department of Cellular and Molecular Medicine and
| | - Frank Wuytack
- From the Laboratory of Cellular Transport Systems, Department of Cellular and Molecular Medicine and
| | - Eveline Lescrinier
- Medicinal Chemistry, Department of Pharmaceutical and Pharmacological Sciences, Rega Institute, KU Leuven, Belgium
| | - Jan Eggermont
- From the Laboratory of Cellular Transport Systems, Department of Cellular and Molecular Medicine and
| | - Peter Vangheluwe
- From the Laboratory of Cellular Transport Systems, Department of Cellular and Molecular Medicine and
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Snyder NA, Palmer MV, Reinhardt TA, Cunningham KW. Milk biosynthesis requires the Golgi cation exchanger TMEM165. J Biol Chem 2019; 294:3181-3191. [PMID: 30622138 PMCID: PMC6398142 DOI: 10.1074/jbc.ra118.006270] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2018] [Revised: 01/02/2019] [Indexed: 11/06/2022] Open
Abstract
Milk is a hallmark of mammals that is critical for normal growth and development of offspring. During biosynthesis of lactose in the Golgi complex, H+ is produced as a by-product, and there is no known mechanism for maintaining luminal pH within the physiological range. Here, using conditional, tissue-specific knockout mice, immunostaining, and biochemical assays, we test whether the putative H+/Ca2+/Mn2+ exchanger known as TMEM165 (transmembrane protein 165) participates in normal milk production. We find TMEM165 is crucial in the lactating mammary gland for normal biosynthesis of lactose and for normal growth rates of nursing pups. The milk of TMEM165-deficient mice contained elevated concentrations of fat, protein, iron, and zinc, which are likely caused by decreased osmosis-mediated dilution of the milk caused by the decreased biosynthesis of lactose. When normalized to total protein levels, only calcium and manganese levels were significantly lower in the milk from TMEM165-deficient dams than control dams. These findings suggest that TMEM165 supplies Ca2+ and Mn2+ to the Golgi complex in exchange for H+ to sustain the functions of lactose synthase and potentially other glycosyl-transferases. Our findings highlight the importance of cation and pH homeostasis in the Golgi complex of professional secretory cells and the critical role of TMEM165 in this process.
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Affiliation(s)
- Nathan A Snyder
- From the Department of Biology, Johns Hopkins University, Baltimore, Maryland 21218 and
| | - Mitchell V Palmer
- the Bacterial Diseases of Livestock, Research Unit, United States Department of Agriculture/Agricultural Research Services, National Animal Disease Center, Ames, Iowa 50010
| | | | - Kyle W Cunningham
- From the Department of Biology, Johns Hopkins University, Baltimore, Maryland 21218 and
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36
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Emrich SM, Yoast RE, Xin P, Zhang X, Pathak T, Nwokonko R, Gueguinou MF, Subedi KP, Zhou Y, Ambudkar IS, Hempel N, Machaca K, Gill DL, Trebak M. Cross-talk between N-terminal and C-terminal domains in stromal interaction molecule 2 (STIM2) determines enhanced STIM2 sensitivity. J Biol Chem 2019; 294:6318-6332. [PMID: 30824535 DOI: 10.1074/jbc.ra118.006801] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [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: 12/17/2018] [Revised: 02/28/2019] [Indexed: 12/20/2022] Open
Abstract
Store-operated Ca2+ entry (SOCE) is a ubiquitous pathway for Ca2+ influx across the plasma membrane (PM). SOCE is mediated by the endoplasmic reticulum (ER)-associated Ca2+-sensing proteins stromal interaction molecule 1 (STIM1) and STIM2, which transition into an active conformation in response to ER Ca2+ store depletion, thereby interacting with and gating PM-associated ORAI1 channels. Although structurally homologous, STIM1 and STIM2 generate distinct Ca2+ signatures in response to varying strengths of agonist stimulation. The physiological functions of these Ca2+ signatures, particularly under native conditions, remain unclear. To investigate the structural properties distinguishing STIM1 and STIM2 activation of ORAI1 channels under native conditions, here we used CRISPR/Cas9 to generate STIM1-/-, STIM2-/-, and STIM1/2-/- knockouts in HEK293 and colorectal HCT116 cells. We show that depending on cell type, STIM2 can significantly sustain SOCE in response to maximal store depletion. Utilizing the SOCE modifier 2-aminoethoxydiphenyl borate (2-APB), we demonstrate that 2-APB-activated store-independent Ca2+ entry is mediated exclusively by endogenous STIM2. Using variants that either stabilize or disrupt intramolecular interactions of STIM C termini, we show that the increased flexibility of the STIM2 C terminus contributes to its selective store-independent activation by 2-APB. However, STIM1 variants with enhanced flexibility in the C terminus failed to support its store-independent activation. STIM1/STIM2 chimeric constructs indicated that coordination between N-terminal sensitivity and C-terminal flexibility is required for specific store-independent STIM2 activation. Our results clarify the structural determinants underlying activation of specific STIM isoforms, insights that are potentially useful for isoform-selective drug targeting.
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Affiliation(s)
- Scott M Emrich
- From the Departments of Cellular and Molecular Physiology and
| | - Ryan E Yoast
- From the Departments of Cellular and Molecular Physiology and
| | - Ping Xin
- From the Departments of Cellular and Molecular Physiology and
| | - Xuexin Zhang
- From the Departments of Cellular and Molecular Physiology and
| | | | - Robert Nwokonko
- From the Departments of Cellular and Molecular Physiology and
| | | | - Krishna P Subedi
- the Secretory Physiology Section, NIDCR, National Institutes of Health, Bethesda, Maryland 20892, and
| | - Yandong Zhou
- From the Departments of Cellular and Molecular Physiology and
| | - Indu S Ambudkar
- the Secretory Physiology Section, NIDCR, National Institutes of Health, Bethesda, Maryland 20892, and
| | - Nadine Hempel
- Pharmacology, Pennsylvania State University College of Medicine, Hershey, Pennsylvania 17033
| | - Khaled Machaca
- the Department of Physiology and Biophysics, Weill Cornell Medical College in Qatar, Education City, Qatar Foundation, P.O. Box 24144, Doha, Qatar
| | - Donald L Gill
- From the Departments of Cellular and Molecular Physiology and
| | - Mohamed Trebak
- From the Departments of Cellular and Molecular Physiology and
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Levy M, Elkoshi N, Barber-Zucker S, Hoch E, Zarivach R, Hershfinkel M, Sekler I. Zinc transporter 10 (ZnT10)-dependent extrusion of cellular Mn 2+ is driven by an active Ca 2+-coupled exchange. J Biol Chem 2019; 294:5879-5889. [PMID: 30755481 DOI: 10.1074/jbc.ra118.006816] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [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: 11/22/2018] [Revised: 01/30/2019] [Indexed: 01/11/2023] Open
Abstract
Manganese (Mn2+) is extruded from the cell by the zinc transporter 10 (ZnT10). Loss of ZnT10 expression caused by autosomal mutations in the ZnT10 gene leads to hypermanganesemia in multiple organs. Here, combining fluorescent monitoring of cation influx in HEK293-T cells expressing human ZnT10 with molecular modeling of ZnT10 cation selectivity, we show that ZnT10 is exploiting the transmembrane Ca2+ inward gradient for active cellular exchange of Mn2+ In analyzing ZnT10 activity we used the ability of Fura-2 to spectrally distinguish between Mn2+ and Ca2+ fluxes. We found that (a) application of Mn2+-containing Ca2+-free solution to ZnT10-expressing cells triggers an influx of Mn2+, (b) reintroduction of Ca2+ leads to cellular Mn2+ extrusion against an inward Mn2+ gradient, and (c) the cellular transport of Mn2+ by ZnT10 is coupled to a reciprocal movement of Ca2+ Remarkably, replacing a single asparagine residue in ZnT10 (Asp-43) with threonine (ZnT10 N43T) converted the Mn2+/Ca2+ exchange to an uncoupled channel mode, permeable to both Ca2+ and Mn2+ The findings in our study identify the first ion transporter that uses the Ca2+ gradient for active counter-ion exchange. They highlight a remarkable versatility in metal selectivity and mode of transport controlled by the tetrahedral metal transport site of ZnT proteins.
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Affiliation(s)
- Moshe Levy
- From the Department of Physiology and Cell Biology, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer Sheva 8410501 Israel
| | - Nadav Elkoshi
- From the Department of Physiology and Cell Biology, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer Sheva 8410501 Israel
| | - Shiran Barber-Zucker
- Department of Life Sciences and The National Institute for Biotechnology in the Negev and Ilse Katz Institute for Nanoscale Science and Technology, Ben-Gurion University of the Negev, Beer Sheva 8410501 Israel
| | - Eitan Hoch
- Program in Medical and Population Genetics and Metabolism Program, Broad Institute of MIT and Harvard, Cambridge, Massachusetts 02142
| | - Raz Zarivach
- Department of Life Sciences and The National Institute for Biotechnology in the Negev and Ilse Katz Institute for Nanoscale Science and Technology, Ben-Gurion University of the Negev, Beer Sheva 8410501 Israel
| | - Michal Hershfinkel
- From the Department of Physiology and Cell Biology, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer Sheva 8410501 Israel
| | - Israel Sekler
- From the Department of Physiology and Cell Biology, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer Sheva 8410501 Israel.
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Frank J, Happeck R, Meier B, Hoang MTT, Stribny J, Hause G, Ding H, Morsomme P, Baginsky S, Peiter E. Chloroplast-localized BICAT proteins shape stromal calcium signals and are required for efficient photosynthesis. New Phytol 2019; 221:866-880. [PMID: 30169890 DOI: 10.1111/nph.15407] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/21/2018] [Accepted: 07/17/2018] [Indexed: 05/18/2023]
Abstract
The photosynthetic machinery of plants must be regulated to maximize the efficiency of light reactions and CO2 fixation. Changes in free Ca2+ in the stroma of chloroplasts have been observed at the transition between light and darkness, and also in response to stress stimuli. Such Ca2+ dynamics have been proposed to regulate photosynthetic capacity. However, the molecular mechanisms of Ca2+ fluxes in the chloroplasts have been unknown. By employing a Ca2+ reporter-based approach, we identified two chloroplast-localized Ca2+ transporters in Arabidopsis thaliana, BICAT1 and BICAT2, that determine the amplitude of the darkness-induced Ca2+ signal in the chloroplast stroma. BICAT2 mediated Ca2+ uptake across the chloroplast envelope, and its knockout mutation strongly dampened the dark-induced [Ca2+ ]stroma signal. Conversely, this Ca2+ transient was increased in knockout mutants of BICAT1, which transports Ca2+ into the thylakoid lumen. Knockout mutation of BICAT2 caused severe defects in chloroplast morphology, pigmentation and photosynthetic light reactions, rendering bicat2 mutants barely viable under autotrophic growth conditions, while bicat1 mutants were less affected. These results show that BICAT transporters play a role in chloroplast Ca2+ homeostasis. They are also involved in the regulation of photosynthesis and plant productivity. Further work will be required to reveal whether the effect on photosynthesis is a direct result of their role as Ca2+ transporters.
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Affiliation(s)
- Julia Frank
- Institute for Biochemistry and Biotechnology, Faculty of Natural Sciences I, Martin Luther University Halle-Wittenberg, D-06120, Halle (Saale), Germany
- Institute of Agricultural and Nutritional Sciences, Faculty of Natural Sciences III, Martin Luther University Halle-Wittenberg, D-06120, Halle (Saale), Germany
| | - Ricardo Happeck
- Institute of Agricultural and Nutritional Sciences, Faculty of Natural Sciences III, Martin Luther University Halle-Wittenberg, D-06120, Halle (Saale), Germany
| | - Bastian Meier
- Institute of Agricultural and Nutritional Sciences, Faculty of Natural Sciences III, Martin Luther University Halle-Wittenberg, D-06120, Halle (Saale), Germany
| | - Minh Thi Thanh Hoang
- Institute of Agricultural and Nutritional Sciences, Faculty of Natural Sciences III, Martin Luther University Halle-Wittenberg, D-06120, Halle (Saale), Germany
| | - Jiri Stribny
- Louvain Institute of Biomolecular Science and Technology (LIBST), Université Catholique de Louvain, B-1348, Louvain-la-Neuve, Belgium
| | - Gerd Hause
- Biocenter, Martin Luther University Halle-Wittenberg, D-06120, Halle (Saale), Germany
| | - Haidong Ding
- Institute of Agricultural and Nutritional Sciences, Faculty of Natural Sciences III, Martin Luther University Halle-Wittenberg, D-06120, Halle (Saale), Germany
- College of Bioscience and Biotechnology, Yangzhou University, Yangzhou, 225009, China
| | - Pierre Morsomme
- Louvain Institute of Biomolecular Science and Technology (LIBST), Université Catholique de Louvain, B-1348, Louvain-la-Neuve, Belgium
| | - Sacha Baginsky
- Institute for Biochemistry and Biotechnology, Faculty of Natural Sciences I, Martin Luther University Halle-Wittenberg, D-06120, Halle (Saale), Germany
| | - Edgar Peiter
- Institute of Agricultural and Nutritional Sciences, Faculty of Natural Sciences III, Martin Luther University Halle-Wittenberg, D-06120, Halle (Saale), Germany
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Wang L, Holmes RP, Peng JB. Modeling the structural and dynamical changes of the epithelial calcium channel TRPV5 caused by the A563T variation based on the structure of TRPV6. J Biomol Struct Dyn 2018; 37:3506-3512. [PMID: 30175942 DOI: 10.1080/07391102.2018.1518790] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [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: 02/08/2023]
Abstract
TRPV5, transient receptor potential cation channel vanilloid subfamily member 5, is an epithelial Ca2+ channel that plays a key role in the active Ca2+ reabsorption process in the kidney. A single nucleotide polymorphism (SNP) rs4252499 in the TRPV5 gene results in an A563T variation in the sixth transmembrane (TM) domain of TRPV5. Our previous study indicated that this variation increases the Ca2+ transport function of TRPV5. To understand the molecular mechanism, a model of TRPV5 was established based on the newly deposited structure of TRPV6 that has 83.1% amino acid identity with TRPV5 in the modeled region. Computational simulations were performed to study the structural and dynamical differences between the TRPV5 variants with A563 and T563. Consistent with the TRPV1-based simulation, the results indicate that the A563T variation increases the contacts between residues 563 and V540, which is one residue away from the key residue D542 in the Ca2+-selective filter. The variation enhanced the stability of the secondary structure of the pore region, decreased the fluctuation of residues around residue 563, and reduced correlated and anti-correlated motion between monomers. Furthermore, the variation increases the pore radius at the selective filter. These findings were confirmed using simulations based on the recently determined structure of rabbit TRPV5. The simulation results provide an explanation for the observation of enhanced Ca2+ influx in TRPV5 caused by the A563T variation. The A563T variation is an interesting example of how a residue distant from the Ca2+-selective filter influences the Ca2+ transport function of the TRPV5 channel. Communicated by Ramaswamy H. Sarma.
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Affiliation(s)
- Lingyun Wang
- a Department of Medicine, Division of Nephrology , Nephrology Research and Training Center, University of Alabama at Birmingham , Birmingham , AL , USA
| | - Ross P Holmes
- b Department of Urology , University of Alabama at Birmingham , Birmingham , AL , USA
| | - Ji-Bin Peng
- a Department of Medicine, Division of Nephrology , Nephrology Research and Training Center, University of Alabama at Birmingham , Birmingham , AL , USA.,b Department of Urology , University of Alabama at Birmingham , Birmingham , AL , USA
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40
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Basso E, Rigotto G, Zucchetti AE, Pozzan T. Slow activation of fast mitochondrial Ca 2+ uptake by cytosolic Ca 2. J Biol Chem 2018; 293:17081-17094. [PMID: 30228190 DOI: 10.1074/jbc.ra118.002332] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [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: 02/08/2018] [Revised: 09/06/2018] [Indexed: 11/06/2022] Open
Abstract
Mitochondrial Ca2+ uptake through the mitochondrial Ca2+ uniporter (MCU) is a tightly controlled process that sustains cell functions mainly by fine-tuning oxidative metabolism to cellular needs. The kinetics of Ca2+ fluxes across the mitochondrial membranes have been studied both in vitro and in vivo for many years, and the discovery of the molecular components of the MCU has further clarified that this Ca2+ uptake mechanism is based on a complex system subject to elaborate layers of controls. Alterations in the speed or capacity of the in-and-out pathways can have detrimental consequences for both the organelle and the cell, impairing cellular metabolism and ultimately causing cell death. Here, we report that pretreatment of deenergized mitochondria with low-micromolar Ca2+ concentrations for a few minutes markedly increases the speed of mitochondrial Ca2+ uptake upon re-addition of an oxidizable substrate. We found that this phenomenon is sensitive to alterations in the level of the MCU modulator proteins mitochondrial calcium uptake 1 (MICU1) and 2 (MICU2), and is accompanied by changes in the association of MICU1-MICU2 complexes with MCU. This increased Ca2+ uptake capacity, occurring under conditions mimicking those during ischemia/reperfusion in vivo, could lead to a massive amount of Ca2+ entering the mitochondrial matrix even at relatively low levels of cytosolic Ca2+ We conclude that the phenomenon uncovered here represents a potential threat of mitochondrial Ca2+ overload to the cell.
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Affiliation(s)
- Emy Basso
- From the National Research Council, Department of Biomedical Science, Neuroscience Institute (Padua Section), 35131 Padua, Italy,
| | - Giulia Rigotto
- the Department of Biomedical Sciences, University of Padua, 35131 Padua, Italy
| | - Andrés E Zucchetti
- the Institut Curie, PSL Research University, INSERM, U932, 26 rue d'Ulm, 75248 Paris Cedex 05, France, and
| | - Tullio Pozzan
- From the National Research Council, Department of Biomedical Science, Neuroscience Institute (Padua Section), 35131 Padua, Italy.,the Department of Biomedical Sciences, University of Padua, 35131 Padua, Italy.,the Venetian Institute of Molecular Medicine, 35129 Padua, Italy
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41
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Joseph SK, Young MP, Alzayady K, Yule DI, Ali M, Booth DM, Hajnóczky G. Redox regulation of type-I inositol trisphosphate receptors in intact mammalian cells. J Biol Chem 2018; 293:17464-17476. [PMID: 30228182 DOI: 10.1074/jbc.ra118.005624] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [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: 08/31/2018] [Revised: 09/09/2018] [Indexed: 12/31/2022] Open
Abstract
A sensitization of inositol 1,4,5-trisphosphate receptor (IP3R)-mediated Ca2+ release is associated with oxidative stress in multiple cell types. These effects are thought to be mediated by alterations in the redox state of critical thiols in the IP3R, but this has not been directly demonstrated in intact cells. Here, we utilized a combination of gel-shift assays with MPEG-maleimides and LC-MS/MS to monitor the redox state of recombinant IP3R1 expressed in HEK293 cells. We found that under basal conditions, ∼5 of the 60 cysteines are oxidized in IP3R1. Cell treatment with 50 μm thimerosal altered gel shifts, indicating oxidation of ∼20 cysteines. By contrast, the shifts induced by 0.5 mm H2O2 or other oxidants were much smaller. Monitoring of biotin-maleimide attachment to IP3R1 by LC-MS/MS with 71% coverage of the receptor sequence revealed modification of two cytosolic (Cys-292 and Cys-1415) and two intraluminal cysteines (Cys-2496 and Cys-2533) under basal conditions. The thimerosal treatment modified an additional eleven cysteines, but only three (Cys-206, Cys-767, and Cys-1459) were consistently oxidized in multiple experiments. H2O2 also oxidized Cys-206 and additionally oxidized two residues not modified by thimerosal (Cys-214 and Cys-1397). Potentiation of IP3R channel function by oxidants was measured with cysteine variants transfected into a HEK293 IP3R triple-knockout cell line, indicating that the functionally relevant redox-sensitive cysteines are predominantly clustered within the N-terminal suppressor domain of IP3R. To our knowledge, this study is the first that has used proteomic methods to assess the redox state of individual thiols in IP3R in intact cells.
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Affiliation(s)
- Suresh K Joseph
- From the MitoCare Center, Department of Pathology, Anatomy, and Cell Biology, Thomas Jefferson University, Philadelphia, Pennsylvania 19107,
| | - Michael P Young
- From the MitoCare Center, Department of Pathology, Anatomy, and Cell Biology, Thomas Jefferson University, Philadelphia, Pennsylvania 19107
| | - Kamil Alzayady
- the Department of Pharmacology & Physiology, University of Rochester, Rochester, New York 14642, and
| | - David I Yule
- the Department of Pharmacology & Physiology, University of Rochester, Rochester, New York 14642, and
| | - Mehboob Ali
- the Center for Perinatal Research, Research Institute, Nationwide Children's Hospital, Columbus, Ohio 43205
| | - David M Booth
- From the MitoCare Center, Department of Pathology, Anatomy, and Cell Biology, Thomas Jefferson University, Philadelphia, Pennsylvania 19107
| | - György Hajnóczky
- From the MitoCare Center, Department of Pathology, Anatomy, and Cell Biology, Thomas Jefferson University, Philadelphia, Pennsylvania 19107
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Chaweewannakorn W, Ariyoshi W, Okinaga T, Fujita Y, Maki K, Nishihara T. Ameloblastin attenuates RANKL-mediated osteoclastogenesis by suppressing activation of nuclear factor of activated T-cell cytoplasmic 1 (NFATc1). J Cell Physiol 2018; 234:1745-1757. [PMID: 30105896 DOI: 10.1002/jcp.27045] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [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: 02/16/2018] [Accepted: 06/25/2018] [Indexed: 01/03/2023]
Abstract
Ameloblastin (Ambn) is an extracellular matrix protein and member of the family of enamel-related gene products. Like amelogenin, Ambn is mainly associated with tooth development, especially biomineralization of enamel. Previous studies have shown reductions in the skeletal dimensions of Ambn-deficient mice, suggesting that the protein also has effects on the differentiation of osteoblasts and/or osteoclasts. However, the specific pathways used by Ambn to influence osteoclast differentiation have yet to be identified. In the present study, two cellular models, one based on bone marrow cells and another on RAW264.7 cells, were used to examine the effects of Ambn on receptor activator of nuclear factor kappa-B ligand (RANKL)-induced osteoclastogenesis. The results showed that Ambn suppresses osteoclast differentiation, cytoskeletal organization, and osteoclast function by the downregulation of the number of tartrate-resistant acid phosphatase (TRAP)-positive multinucleated osteoclasts, actin ring formation, and areas of pit resorption. The expression of the osteoclast-specific genes TRAP, MMP9, cathepsin K, and osteoclast stimulatory transmembrane protein (OC-STAMP) was abolished in the presence of Ambn, while that of nuclear factor of activated T cells cytoplasmic 1 (NFATc1), the master regulatory factor of osteoclastogenesis, was also attenuated by the downregulation of c-Fos expression. In Ambn-induced RAW264.7 cells, phosphorylation of cAMP-response element-binding protein (CREB), c-Jun N-terminal kinase (JNK), and p38 mitogen-activated protein kinase (p38 MAPK), but not extracellular signal-regulated kinase 1/2 (ERK1/2), was reduced. Calcium oscillation was also decreased in the presence of Ambn, suggesting its involvement in both RANKL-induced osteoclastogenesis and costimulatory signaling. B-lymphocyte-induced maturation protein-1 (Blimp1), a transcriptional repressor of negative regulators of osteoclastogenesis, was also downregulated by Ambn, resulting in the elevated expression of v-maf musculoaponeurotic fibrosarcoma oncogene family, protein B (MafB), B-cell lymphoma 6 (Bcl6), and interferon regulatory factor-8 (Irf8). Taken together, these findings suggest that Ambn suppresses RANKL-induced osteoclastogenesis by modulating the NFATc1 axis.
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Affiliation(s)
- Wichida Chaweewannakorn
- Division of Infections and Molecular Biology, Department of Health Promotion, Kyushu Dental University, Fukuoka, Japan.,Division of Developmental Stomatognathic Function Science, Department of Health Promotion, Kyushu Dental University, Fukuoka, Japan
| | - Wataru Ariyoshi
- Division of Infections and Molecular Biology, Department of Health Promotion, Kyushu Dental University, Fukuoka, Japan
| | - Toshinori Okinaga
- Division of Infections and Molecular Biology, Department of Health Promotion, Kyushu Dental University, Fukuoka, Japan
| | - Yuko Fujita
- Division of Developmental Stomatognathic Function Science, Department of Health Promotion, Kyushu Dental University, Fukuoka, Japan
| | - Kenshi Maki
- Division of Developmental Stomatognathic Function Science, Department of Health Promotion, Kyushu Dental University, Fukuoka, Japan
| | - Tatsuji Nishihara
- Division of Infections and Molecular Biology, Department of Health Promotion, Kyushu Dental University, Fukuoka, Japan
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Raguimova ON, Smolin N, Bovo E, Bhayani S, Autry JM, Zima AV, Robia SL. Redistribution of SERCA calcium pump conformers during intracellular calcium signaling. J Biol Chem 2018; 293:10843-10856. [PMID: 29764938 PMCID: PMC6052202 DOI: 10.1074/jbc.ra118.002472] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2018] [Revised: 05/01/2018] [Indexed: 11/06/2022] Open
Abstract
The conformational changes of a calcium transport ATPase were investigated with molecular dynamics (MD) simulations as well as fluorescence resonance energy transfer (FRET) measurements to determine the significance of a discrete structural element for regulation of the conformational dynamics of the transport cycle. Previous MD simulations indicated that a loop in the cytosolic domain of the SERCA calcium transporter facilitates an open-to-closed structural transition. To investigate the significance of this structural element, we performed additional MD simulations and new biophysical measurements of SERCA structure and function. Rationally designed in silico mutations of three acidic residues of the loop decreased SERCA domain-domain contacts and increased domain-domain separation distances. Principal component analysis of MD simulations suggested decreased sampling of compact conformations upon N-loop mutagenesis. Deficits in headpiece structural dynamics were also detected by measuring intramolecular FRET of a Cer-YFP-SERCA construct (2-color SERCA). Compared with WT, the mutated 2-color SERCA shows a partial FRET response to calcium, whereas retaining full responsiveness to the inhibitor thapsigargin. Functional measurements showed that the mutated transporter still hydrolyzes ATP and transports calcium, but that maximal enzyme activity is reduced while maintaining similar calcium affinity. In live cells, calcium elevations resulted in concomitant FRET changes as the population of WT 2-color SERCA molecules redistributed among intermediates of the transport cycle. Our results provide novel insights on how the population of SERCA pumps responds to dynamic changes in intracellular calcium.
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Affiliation(s)
- Olga N Raguimova
- From the Department of Cell and Molecular Physiology, Loyola University Chicago, Maywood, Illinois 60153 and
| | - Nikolai Smolin
- From the Department of Cell and Molecular Physiology, Loyola University Chicago, Maywood, Illinois 60153 and
| | - Elisa Bovo
- From the Department of Cell and Molecular Physiology, Loyola University Chicago, Maywood, Illinois 60153 and
| | - Siddharth Bhayani
- From the Department of Cell and Molecular Physiology, Loyola University Chicago, Maywood, Illinois 60153 and
| | - Joseph M Autry
- the Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, Minnesota 55455
| | - Aleksey V Zima
- From the Department of Cell and Molecular Physiology, Loyola University Chicago, Maywood, Illinois 60153 and
| | - Seth L Robia
- From the Department of Cell and Molecular Physiology, Loyola University Chicago, Maywood, Illinois 60153 and
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Moor MB, Haenzi B, Legrand F, Koesters R, Hynes NE, Bonny O. Renal Memo1 Differentially Regulates the Expression of Vitamin D-Dependent Distal Renal Tubular Calcium Transporters. Front Physiol 2018; 9:874. [PMID: 30038585 PMCID: PMC6046545 DOI: 10.3389/fphys.2018.00874] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [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: 03/11/2018] [Accepted: 06/19/2018] [Indexed: 01/11/2023] Open
Abstract
Ablation of the Mediator of ErbB2-driven Cell Motility 1 (Memo1) in mice altered calcium homeostasis and renal calcium transporter abundance by an unknown mechanism. Here, we investigated the role of intrarenal Memo in renal calcium handling. We have generated a mouse model of inducible kidney-specific Memo1 deletion. The Memo-deficient mice showed normal serum concentration and urinary excretion of calcium and phosphate, but elevated serum FGF23 concentration. They displayed elevated gene expression and protein abundance of the distal renal calcium transporters NCX1, TRPV5, and calbindin D28k. In addition, Claudin 14 gene expression was increased. When the mice were challenged by a vitamin D deficient diet, serum FGF23 concentration and TRPV5 membrane abundance were decreased, but NCX1 abundance remained increased. Collectively, renal distal calcium transport proteins (TRPV5 and Calbindin-D28k) in this model were altered by Memo- and vitamin-D dependent mechanisms, except for NCX1 which was vitamin D-independent. These findings highlight the existence of distinct regulatory mechanisms affecting TRPV5 and NCX1 membrane expression in vivo.
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Affiliation(s)
- Matthias B. Moor
- Department of Pharmacology and Toxicology, University of Lausanne, Lausanne, Switzerland
| | - Barbara Haenzi
- Department of Pharmacology and Toxicology, University of Lausanne, Lausanne, Switzerland
| | - Finola Legrand
- Department of Pharmacology and Toxicology, University of Lausanne, Lausanne, Switzerland
| | - Robert Koesters
- Department of Nephrology, Hôpital Tenon, Université Pierre et Marie Curie, Paris, France
| | - Nancy E. Hynes
- Friedrich Miescher Institute for Biomedical Research, Basel, Switzerland
| | - Olivier Bonny
- Department of Pharmacology and Toxicology, University of Lausanne, Lausanne, Switzerland
- Service of Nephrology, Department of Medicine, Lausanne University Hospital, Lausanne, Switzerland
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Kushwaha AK, Apolis L, Ito D, Desai SA. Increased Ca ++ uptake by erythrocytes infected with malaria parasites: Evidence for exported proteins and novel inhibitors. Cell Microbiol 2018; 20:e12853. [PMID: 29726084 DOI: 10.1111/cmi.12853] [Citation(s) in RCA: 6] [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: 01/19/2018] [Revised: 04/18/2018] [Accepted: 04/24/2018] [Indexed: 12/12/2022]
Abstract
Malaria parasites export many proteins into their host erythrocytes and increase membrane permeability to diverse solutes. Although most solutes use a broad-selectivity channel known as the plasmodial surface anion channel, increased Ca++ uptake is mediated by a distinct, poorly characterised mechanism that appears to be essential for the intracellular parasite. Here, we examined infected cell Ca++ uptake with a kinetic fluorescence assay and the virulent human pathogen, Plasmodium falciparum. Cell surface labelling with N-hydroxysulfosuccinimide esters revealed differing effects on transport into infected and uninfected cells, indicating that Ca++ uptake at the infected cell surface is mediated by new or altered proteins at the host membrane. Conditional knockdown of PTEX, a translocon for export of parasite proteins into the host cell, significantly reduced infected cell Ca++ permeability, suggesting involvement of parasite-encoded proteins trafficked to the host membrane. A high-throughput chemical screen identified the first Ca++ transport inhibitors active against Plasmodium-infected cells. These novel chemical scaffolds inhibit both uptake and parasite growth; improved in vitro potency at reduced free [Ca++ ] is consistent with parasite killing specifically via action on one or more Ca++ transporters. These inhibitors should provide mechanistic insights into malaria parasite Ca++ transport and may be starting points for new antimalarial drugs.
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Affiliation(s)
- Ambuj K Kushwaha
- The Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, Maryland, USA
| | - Liana Apolis
- The Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, Maryland, USA
| | - Daisuke Ito
- The Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, Maryland, USA
| | - Sanjay A Desai
- The Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, Maryland, USA
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46
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Thines L, Deschamps A, Sengottaiyan P, Savel O, Stribny J, Morsomme P. The yeast protein Gdt1p transports Mn 2+ ions and thereby regulates manganese homeostasis in the Golgi. J Biol Chem 2018; 293:8048-8055. [PMID: 29632074 DOI: 10.1074/jbc.ra118.002324] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [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: 02/07/2018] [Revised: 04/05/2018] [Indexed: 11/06/2022] Open
Abstract
The uncharacterized protein family 0016 (UPF0016) is a family of secondary ion transporters implicated in calcium homeostasis and some diseases. More precisely, genetic variants of the human UPF0016 ortholog transmembrane protein 165 (TMEM165) have been linked to congenital disorders of glycosylation (CDG). The Saccharomyces cerevisiae ortholog Gdt1p has been shown to be involved in calcium homeostasis and protein glycosylation. Moreover, plant and bacterial UPF0016 members appear to have putative roles in Mn2+ homeostasis. Here, we produced the yeast UPF0016 member Gdt1p in the bacterial host Lactococcus lactis Using Mn2+-induced quenching of Fura-2-emitted fluorescence, we observed that Gdt1p mediates Mn2+ influx, in addition to its previously reported regulation of Ca2+ influx. The estimated Km values of Gdt1p of 15.6 ± 2.6 μm for Ca2+ and 83.2 ± 9.8 μm for Mn2+ indicated that Gdt1p has a higher affinity for Ca2+ than for Mn2+ In yeast cells, we found that Gdt1p is involved in the resistance to high Mn2+ concentration and controls total Mn2+ stores. Lastly, we demonstrated that GDT1 deletion affects the activity of the yeast Mn2+-dependent Sod2p superoxide dismutase, most likely by modulating cytosolic Mn2+ concentrations. Taken together, we obtained first evidence that Gdt1p from yeast directly transports manganese, which strongly reinforces the suggested link between the UPF0016 family and Mn2+ homeostasis and provides new insights into the molecular causes of human TMEM165-associated CDGs. Our results also shed light on how yeast cells may regulate Golgi intraluminal concentrations of manganese, a key cofactor of many enzymes involved in protein glycosylation.
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Affiliation(s)
- Louise Thines
- Institut des Sciences de la Vie, Université catholique de Louvain, B-1348 Louvain-la-Neuve, Belgium
| | - Antoine Deschamps
- Institut des Sciences de la Vie, Université catholique de Louvain, B-1348 Louvain-la-Neuve, Belgium
| | - Palanivelu Sengottaiyan
- Institut des Sciences de la Vie, Université catholique de Louvain, B-1348 Louvain-la-Neuve, Belgium
| | - Oksana Savel
- Institut des Sciences de la Vie, Université catholique de Louvain, B-1348 Louvain-la-Neuve, Belgium
| | - Jiri Stribny
- Institut des Sciences de la Vie, Université catholique de Louvain, B-1348 Louvain-la-Neuve, Belgium
| | - Pierre Morsomme
- Institut des Sciences de la Vie, Université catholique de Louvain, B-1348 Louvain-la-Neuve, Belgium.
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Smail M, Al Kury L, Qureshi MA, Shmygol A, Oz M, Singh J, Howarth FC. Cell shortening and calcium dynamics in epicardial and endocardial myocytes from the left ventricle of Goto-Kakizaki type 2 diabetic rats. Exp Physiol 2018; 103:502-511. [PMID: 29363193 DOI: 10.1113/ep086542] [Citation(s) in RCA: 3] [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: 06/20/2017] [Accepted: 01/17/2018] [Indexed: 01/18/2023]
Abstract
NEW FINDINGS What is the central question of this study? To investigate haemodynamic dysfunction in the type 2 diabetic Goto-Kakizaki (GK) rat, we measured shortening and Ca2+ transport in ventricular myocytes from epicardial (EPI) and endocardial (ENDO) regions. What is the main finding and its importance? EPI and ENDO GK myocytes displayed similar hypertrophy. Time to peak (TPK) and time to half (THALF) relaxation were prolonged in EPI GK myocytes. TPK Ca2+ transient was prolonged and THALF decay of the Ca2+ transient was shortened in EPI GK myocytes. Amplitude of shortening, Ca2+ transient and sarcoplasmic reticulum Ca2+ were unaltered in EPI and ENDO myocytes from Goto-Kakizaki compared with control rats. We demostrated regional differences in shortening and Ca2+ transport in Goto-Kakizaki rats. ABSTRACT Diabetic cardiomyopathy is considered to be one of the major diabetes-associated complications, and the pathogenesis of cardiac dysfunction is not well understood. The electromechanical properties of cardiac myocytes vary across the walls of the chambers. The aim of this study was to investigate shortening and Ca2+ transport in epicardial (EPI) and endocardial (ENDO) left ventricular myocytes in the Goto-Kakizaki (GK) type 2 diabetic rat heart. Shortening and intracellular Ca2+ transients were measured by video edge detection and fluorescence photometry. Myocyte surface area was increased in EPI-GK and ENDO-GK compared with control EPI-CON and ENDO-CON myocytes. Time to peak shortening was prolonged in EPI-GK compared with EPI-CON and in ENDO-CON compared with EPI-CON myocytes. Time to half-relaxation of shortening and time to peak Ca2+ transient were prolonged in EPI-GK compared with EPI-CON myocytes. Time to half-decay of the Ca2+ transient was prolonged in EPI-CON compared with EPI-GK and in EPI-CON compared with ENDO-CON myocytes. The amplitude of shortening and the Ca2+ transient were unaltered in EPI-GK and ENDO-GK compared with their respective controls. Sarcoplasmic reticulum Ca2+ and myofilament sensitivity to Ca2+ were unaltered in EPI-GK and ENDO-GK compared with their respective controls. Regional differences in Ca2+ signalling in healthy and diabetic myocytes might account for variation in the dynamics of myocyte shortening. Further studies will be required to clarify the mechanisms underlying regional differences in the time course of shortening and the Ca2+ transient in EPI and ENDO myocytes from diabetic and control hearts.
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Affiliation(s)
- Manal Smail
- Department of Physiology, College of Medicine & Health Sciences, UAE University, Al Ain, United Arab Emirates
| | - Lina Al Kury
- College of Natural and Health Sciences, Zayed University, Abu Dhabi, United Arab Emirates
| | - Muhammad Anwar Qureshi
- Department of Physiology, College of Medicine & Health Sciences, UAE University, Al Ain, United Arab Emirates
| | - Anatoliy Shmygol
- Department of Physiology, College of Medicine & Health Sciences, UAE University, Al Ain, United Arab Emirates
| | - Murat Oz
- Department of Basic Medical Sciences, College of Medicine, Qatar University, Doha, Qatar
| | - Jaipaul Singh
- School of Forensic & Applied Sciences, University of Central Lancashire, Preston, UK
| | - Frank Christopher Howarth
- Department of Physiology, College of Medicine & Health Sciences, UAE University, Al Ain, United Arab Emirates
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Hamamoto S, Mori Y, Yabe I, Uozumi N. In vitro and in vivo characterization of modulation of the vacuolar cation channel TRPY1 from Saccharomyces cerevisiae. FEBS J 2018; 285:1146-1161. [PMID: 29405580 DOI: 10.1111/febs.14399] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [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: 06/05/2017] [Revised: 11/29/2017] [Accepted: 01/30/2018] [Indexed: 01/08/2023]
Abstract
Saccharomyces cerevisiae possesses a transient receptor potential (TRP) channel homolog TRPY1 in its vacuolar membrane, considered to be an ancestral TRP channel. So far, studies have focused on the channel properties of TRPY1, but its regulation and physiologic role remained to be elucidated. Here, we investigated TRPY1 channel function in vitro and in vivo. Patch-clamp recording of TRPY1 in yeast vacuolar membranes showed that Ca2+ on the lumen side inhibited TRPY1-mediated channel activity, whereas luminal Zn2+ increased the currents. TRPY1 was activated in the presence of a reducing agent, 2-mercaptoethanol. The cysteine at position 624 was identified as the target for this activating action. This activation was independent of the presence of cytosolic Ca2+ . The amplitude of TRPY1-mediated current was reduced by addition of phosphatidylinositol 3-phosphate on the cytosolic side but not by phosphatidylinositol (PI) or phosphatidylinositol 3,5-phosphate. Measurement of the transient Ca2+ increase in response to hyper-osmotic shock in several yeast mutants defective in different steps of the PI phosphate biogenesis pathway supported this interpretation. Addition of a microtubule inhibitor strongly decreased the transient cytosolic Ca2+ increase upon hyper-osmotic shock. Taken together, the data indicate that the vacuolar TRPY1 Ca2+ channel mediates the perception of cytosolic signals that were induced by external changes in osmolarity, and participates in the modulation of cytosolic calcium signaling through Ca2+ release from the vacuole to maintain intracellular Ca2+ homeostasis in yeast.
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Affiliation(s)
- Shin Hamamoto
- Department of Biomolecular Engineering, Graduate School of Engineering, Tohoku University, Sendai, Japan
| | - Yasuo Mori
- Department of Synthetic Chemistry and Biological Chemistry, Graduate School of Engineering, Kyoto University, Japan
| | - Isamu Yabe
- Department of Green and Sustainable Chemistry, Tokyo Denki University, Japan
| | - Nobuyuki Uozumi
- Department of Biomolecular Engineering, Graduate School of Engineering, Tohoku University, Sendai, Japan
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49
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Mikkelsen SA, Vangheluwe P, Andersen JP. A Darier disease mutation relieves kinetic constraints imposed by the tail of sarco(endo)plasmic reticulum Ca 2+-ATPase 2b. J Biol Chem 2018; 293:3880-3889. [PMID: 29363575 DOI: 10.1074/jbc.ra117.000941] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [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: 11/13/2017] [Revised: 01/19/2018] [Indexed: 11/06/2022] Open
Abstract
The sarco(endo)plasmic reticulum Ca2+-ATPase (SERCA) 2b isoform possesses an extended C terminus (SERCA2b tail) forming an 11th transmembrane (TM) helix, which slows conformational changes of the Ca2+-pump reaction cycle. Here, we report that a Darier disease (DD) mutation of SERCA2b that changes a glutamate to a lysine in the cytoplasmic loop between TM8 and TM9 (E917K) relieves these kinetic constraints. We analyzed the effects of this mutation on the overall reaction and the individual partial reactions of the Ca2+ pump compared with the corresponding mutations of the SERCA2a and SERCA1a isoforms, lacking the SERCA2b tail. In addition to a reduced affinity for Ca2+, caused by the mutation in all three isoforms examined, we observed a unique enhancing effect on the turnover rates of ATPase activity and Ca2+ transport for the SERCA2b E917K mutation. This relief of kinetic constraints contrasted with inhibitory effects observed for the corresponding SERCA2a and SERCA1a (E918K) mutations. These observations indicated that the E917K/E918K mutations affect the rate-limiting conformational change in isoform-specific ways and that the SERCA2b mutation perturbs the interactions of TM11 with other SERCA2b regions. Mutational analysis of an arginine in TM7 that interacts with the glutamate in SERCA1a crystal structures suggested that in wildtype SERCA2b, the corresponding arginine (Arg-835) may be involved in mediating the conformational restriction by TM11. Moreover, the E917K mutation may disturb TM11 through the cytoplasmic loop between TM10 and TM11. In conclusion, our findings have identified structural elements of importance for the kinetic constraints imposed by TM11.
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Affiliation(s)
- Stine A Mikkelsen
- From the Department of Biomedicine, Aarhus University, DK-8000 Aarhus C, Denmark and
| | - Peter Vangheluwe
- the Department of Cellular and Molecular Medicine, KU Leuven, B-3000 Leuven, Belgium
| | - Jens Peter Andersen
- From the Department of Biomedicine, Aarhus University, DK-8000 Aarhus C, Denmark and
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50
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Iida K, Teng J, Cho T, Yoshikawa-Kimura S, Iida H. Post-translational processing and membrane translocation of the yeast regulatory Mid1 subunit of the Cch1/VGCC/NALCN cation channel family. J Biol Chem 2017; 292:20570-20582. [PMID: 29042437 PMCID: PMC5733593 DOI: 10.1074/jbc.m117.810283] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2017] [Revised: 09/20/2017] [Indexed: 12/24/2022] Open
Abstract
Saccharomyces cerevisiae Mid1 is composed of 548 amino acids and a regulatory subunit of Cch1, a member of the eukaryotic pore-forming, four-domain cation channel family. The amino acid sequence and voltage insensitivity of Cch1 are more similar to those of Na+ leak channel non-selective (NALCN) than to the α1 subunit of voltage-gated Ca2+ channels (VGCCs). Despite a lack in overall primary sequence similarity, Mid1 resembles in some aspects VGCC α2/δ regulatory subunits and NALCN-associated proteins. Unlike animal α2/δ subunits, Mid1 and NALCN-associated proteins are essential for the function of the pore-forming subunit. We herein investigated the processing and membrane translocation of Mid1. Mid1 was found to have a 20-amino-acid-long N-terminal signal peptide and appeared to be entirely localized extracellularly. A signal peptide-deleted Mid1 protein, Mid1ΔN23, was N-glycosylated and retained Ca2+ influx activity through Cch1. Moreover, an N-terminal truncation analysis revealed that even truncated Mid1 lacking 209 N-terminal amino acid residues was N-glycosylated and maintained Ca2+ influx activity. A 219-amino-acid-truncated Mid1 protein lost this activity but was still N-glycosylated. In the sec71Δ and sec72Δ single mutants defective in the post-translational protein transport into the endoplasmic reticulum (ER), Mid1ΔN23 could not mediate Ca2+ influx and did not undergo N-glycosylation, whereas wild-type Mid1 exhibited normal Ca2+ influx activity and N-glycosylation in these mutants. Therefore, the signal peptide-lacking Mid1ΔN23 protein may be translocated to the ER exclusively through the post-translational protein translocation, which typically requires an N-terminal signal peptide. Mid1 may provide a tool for studying mechanisms of protein translocation into the ER.
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Affiliation(s)
- Kazuko Iida
- From the Laboratory of Biomembrane, Tokyo Metropolitan Institute of Medical Science, 2-1-6 Kamikitazawa, Setagaya, Tokyo 156-8506, Japan and
| | - Jinfeng Teng
- the Department of Biology, Tokyo Gakugei University, 4-1-1 Nukui kita-machi, Koganei, Tokyo 184-8501, Japan
| | - Toshihiko Cho
- the Department of Biology, Tokyo Gakugei University, 4-1-1 Nukui kita-machi, Koganei, Tokyo 184-8501, Japan
| | - Sato Yoshikawa-Kimura
- the Department of Biology, Tokyo Gakugei University, 4-1-1 Nukui kita-machi, Koganei, Tokyo 184-8501, Japan
| | - Hidetoshi Iida
- the Department of Biology, Tokyo Gakugei University, 4-1-1 Nukui kita-machi, Koganei, Tokyo 184-8501, Japan
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