1
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Fresquez AM, Hogan JO, Rivera P, Patterson KM, Singer K, Reynolds JM, White C. STIM1-Dependent Store-Operated Calcium Entry Mediates Sex Differences in Macrophage Chemotaxis and Monocyte Recruitment. J Biol Chem 2024:107422. [PMID: 38815866 DOI: 10.1016/j.jbc.2024.107422] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2023] [Revised: 05/09/2024] [Accepted: 05/22/2024] [Indexed: 06/01/2024] Open
Abstract
Infiltration of monocyte-derived cells to sites of infection and injury is greater in males than in females, due in part, to increased chemotaxis, the process of directed cell movement toward a chemical signal. The mechanisms governing sexual dimorphism in chemotaxis are not known. We hypothesized a role for the store-operated calcium entry (SOCE) pathway in regulating chemotaxis by modulating leading and trailing edge membrane dynamics. We measured the chemotactic response of bone marrow derived macrophages (BMDMs) migrating towards complement component 5a (C5a). Chemotactic ability was dependent on sex and inflammatory phenotype (M0, M1, M2), and correlated with SOCE. Notably, females exhibited a significantly lower magnitude of SOCE than males. When we knocked out the SOCE gene, stromal interaction molecule 1 (STIM1), it eliminated SOCE and equalized chemotaxis across both sexes. Analysis of membrane dynamics at the leading and trailing edges showed that STIM1 influences chemotaxis by facilitating retraction of the trailing edge. Using BTP2 to pharmacologically inhibit SOCE mirrored the effects of STIM1 knockout, demonstrating a central role of STIM/Orai-mediated calcium signaling. Importantly, by monitoring the recruitment of adoptively transferred monocytes in an in vivo model of peritonitis, we show that increased infiltration of male monocytes during infection is dependent on STIM1. These data support a model in which STIM1-dependent SOCE is necessary and sufficient for mediating the sex difference in monocyte recruitment and macrophage chemotactic ability by regulating trailing edge dynamics.
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Affiliation(s)
- Adriana M Fresquez
- Physiology & Biophysics; Center for Cancer Cell Biology, Immunology, and Infection, Rosalind Franklin University of Medicine & Science, North Chicago, IL
| | - James O Hogan
- Physiology & Biophysics; Center for Cancer Cell Biology, Immunology, and Infection, Rosalind Franklin University of Medicine & Science, North Chicago, IL
| | - Patricia Rivera
- Physiology & Biophysics; Center for Cancer Cell Biology, Immunology, and Infection, Rosalind Franklin University of Medicine & Science, North Chicago, IL
| | - Kristen M Patterson
- Microbiology and Immunology; Center for Cancer Cell Biology, Immunology, and Infection, Rosalind Franklin University of Medicine & Science, North Chicago, IL
| | - Kanakadurga Singer
- Department of Pediatrics, Michigan Medicine, University of Michigan, Ann Arbor, MI
| | - Joseph M Reynolds
- Microbiology and Immunology; Center for Cancer Cell Biology, Immunology, and Infection, Rosalind Franklin University of Medicine & Science, North Chicago, IL
| | - Carl White
- Physiology & Biophysics; Center for Cancer Cell Biology, Immunology, and Infection, Rosalind Franklin University of Medicine & Science, North Chicago, IL.
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2
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Alemán OR, Rosales C. Human neutrophil Fc gamma receptors: different buttons for different responses. J Leukoc Biol 2023; 114:571-584. [PMID: 37437115 DOI: 10.1093/jleuko/qiad080] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2023] [Revised: 05/31/2023] [Accepted: 06/28/2023] [Indexed: 07/14/2023] Open
Abstract
Neutrophils are fundamental cells in host defense. These leukocytes are quickly recruited from the blood to sites of infection or tissue damage. At these sites, neutrophils initiate several innate immune responses, including phagocytosis, production of reactive oxygen species, degranulation to release proteases and other antimicrobial compounds, production of inflammatory mediators, and formation of neutrophil extracellular traps. In addition to their role in innate immunity, neutrophils are now recognized as cells that also regulate adaptive immunity, via interaction with dendritic cells and lymphocytes. Neutrophils also respond to adaptive immunity by interacting with antibody molecules. Indeed, antibody molecules allow neutrophils to have antigen-specific responses. Neutrophils express different receptors for antibodies. The receptors for immunoglobulin G molecules are known as Fcγ receptors. Upon Fcγ receptor aggregation on the cell membrane, these receptors trigger distinct signal transduction cascades that activate particular cellular responses. In this review, we describe the major Fcγ receptors expressed on human neutrophils and discuss how each Fcγ receptor activates a choice of signaling pathways to stimulate particular neutrophil responses.
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Affiliation(s)
- Omar Rafael Alemán
- Departamento de Inmunología, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Apdo. Postal 70228, Ciudad Universitaria, Ciudad de México 04510, México
| | - Carlos Rosales
- Departamento de Inmunología, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Apdo. Postal 70228, Ciudad Universitaria, Ciudad de México 04510, México
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3
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Talbi K, Ousingsawat J, Centeio R, Schreiber R, Kunzelmann K. KCNE1 does not shift TMEM16A from a Ca 2+ dependent to a voltage dependent Cl - channel and is not expressed in renal proximal tubule. Pflugers Arch 2023:10.1007/s00424-023-02829-5. [PMID: 37442855 PMCID: PMC10359377 DOI: 10.1007/s00424-023-02829-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2023] [Revised: 05/02/2023] [Accepted: 06/08/2023] [Indexed: 07/15/2023]
Abstract
The TMEM16A (ANO1) Cl- channel is activated by Ca2+ in a voltage-dependent manner. It is broadly expressed and was shown to be also present in renal proximal tubule (RPT). KCNQ1 is an entirely different K+ selective channel that forms the cardiac IKS potassium channel together with its ß-subunit KCNE1. Surprisingly, KCNE1 has been claimed to interact with TMEM16A, and to be required for activation of TMEM16A in mouse RPT. Interaction with KCNE1 was reported to switch TMEM16A from a Ca22+-dependent to a voltage-dependent ion channel. Here we demonstrate that KCNE1 is not expressed in mouse RPT. TMEM16A expressed in RPT is activated by angiotensin II and ATP in a KCNE1-independent manner. Coexpression of KCNE1 does not change TMEM16A to a voltage gated Cl- channel and Ca2+-dependent regulation of TMEM16A is fully maintained in the presence of KCNE1. While overexpressed KCNE1 slightly affects Ca2+-dependent regulation of TMEM16A, the data provide no evidence for KCNE1 being an auxiliary functional subunit for TMEM16A.
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Affiliation(s)
- Khaoula Talbi
- Physiological Institute, University of Regensburg, University street 31, D-93053, Regensburg, Germany
| | - Jiraporn Ousingsawat
- Physiological Institute, University of Regensburg, University street 31, D-93053, Regensburg, Germany
| | - Raquel Centeio
- Physiological Institute, University of Regensburg, University street 31, D-93053, Regensburg, Germany
| | - Rainer Schreiber
- Physiological Institute, University of Regensburg, University street 31, D-93053, Regensburg, Germany
| | - Karl Kunzelmann
- Physiological Institute, University of Regensburg, University street 31, D-93053, Regensburg, Germany.
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4
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Lia A, Sansevero G, Chiavegato A, Sbrissa M, Pendin D, Mariotti L, Pozzan T, Berardi N, Carmignoto G, Fasolato C, Zonta M. Rescue of astrocyte activity by the calcium sensor STIM1 restores long-term synaptic plasticity in female mice modelling Alzheimer's disease. Nat Commun 2023; 14:1590. [PMID: 36949142 PMCID: PMC10033875 DOI: 10.1038/s41467-023-37240-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2022] [Accepted: 03/09/2023] [Indexed: 03/24/2023] Open
Abstract
Calcium dynamics in astrocytes represent a fundamental signal that through gliotransmitter release regulates synaptic plasticity and behaviour. Here we present a longitudinal study in the PS2APP mouse model of Alzheimer's disease (AD) linking astrocyte Ca2+ hypoactivity to memory loss. At the onset of plaque deposition, somatosensory cortical astrocytes of AD female mice exhibit a drastic reduction of Ca2+ signaling, closely associated with decreased endoplasmic reticulum Ca2+ concentration and reduced expression of the Ca2+ sensor STIM1. In parallel, astrocyte-dependent long-term synaptic plasticity declines in the somatosensory circuitry, anticipating specific tactile memory loss. Notably, we show that both astrocyte Ca2+ signaling and long-term synaptic plasticity are fully recovered by selective STIM1 overexpression in astrocytes. Our data unveil astrocyte Ca2+ hypoactivity in neocortical astrocytes as a functional hallmark of early AD stages and indicate astrocytic STIM1 as a target to rescue memory deficits.
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Affiliation(s)
- Annamaria Lia
- Neuroscience Institute, National Research Council (CNR), Padua, Italy
- Department of Biomedical Sciences, University of Padua, Padua, Italy
| | - Gabriele Sansevero
- Neuroscience Institute, National Research Council (CNR), Pisa, Italy
- Department of NEUROFARBA, University of Florence, Florence, Italy
| | - Angela Chiavegato
- Department of Biomedical Sciences, University of Padua, Padua, Italy
| | - Miriana Sbrissa
- Department of Biomedical Sciences, University of Padua, Padua, Italy
| | - Diana Pendin
- Neuroscience Institute, National Research Council (CNR), Padua, Italy
- Department of Biomedical Sciences, University of Padua, Padua, Italy
| | - Letizia Mariotti
- Neuroscience Institute, National Research Council (CNR), Padua, Italy
- Department of Biomedical Sciences, University of Padua, Padua, Italy
| | - Tullio Pozzan
- Neuroscience Institute, National Research Council (CNR), Padua, Italy
- Department of Biomedical Sciences, University of Padua, Padua, Italy
- Veneto Institute of Molecular Medicine, Foundation for Advanced Biomedical Research, Padua, Italy
| | - Nicoletta Berardi
- Neuroscience Institute, National Research Council (CNR), Pisa, Italy
- Department of NEUROFARBA, University of Florence, Florence, Italy
| | - Giorgio Carmignoto
- Neuroscience Institute, National Research Council (CNR), Padua, Italy.
- Department of Biomedical Sciences, University of Padua, Padua, Italy.
| | - Cristina Fasolato
- Department of Biomedical Sciences, University of Padua, Padua, Italy.
| | - Micaela Zonta
- Neuroscience Institute, National Research Council (CNR), Padua, Italy.
- Department of Biomedical Sciences, University of Padua, Padua, Italy.
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5
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Yeung PSW, Yamashita M, Prakriya M. A pathogenic human Orai1 mutation unmasks STIM1-independent rapid inactivation of Orai1 channels. eLife 2023; 12:82281. [PMID: 36806330 PMCID: PMC9991058 DOI: 10.7554/elife.82281] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2022] [Accepted: 02/10/2023] [Indexed: 02/22/2023] Open
Abstract
Ca2+ release-activated Ca2+ (CRAC) channels are activated by direct physical interactions between Orai1, the channel protein, and STIM1, the endoplasmic reticulum Ca2+ sensor. A hallmark of CRAC channels is fast Ca2+-dependent inactivation (CDI) which provides negative feedback to limit Ca2+ entry through CRAC channels. Although STIM1 is thought to be essential for CDI, its molecular mechanism remains largely unknown. Here, we examined a poorly understood gain-of-function (GOF) human Orai1 disease mutation, L138F, that causes tubular aggregate myopathy. Through pairwise mutational analysis, we determine that large amino acid substitutions at either L138 or the neighboring T92 locus located on the pore helix evoke highly Ca2+-selective currents in the absence of STIM1. We find that the GOF phenotype of the L138 pathogenic mutation arises due to steric clash between L138 and T92. Surprisingly, strongly activating L138 and T92 mutations showed CDI in the absence of STIM1, contradicting prevailing views that STIM1 is required for CDI. CDI of constitutively open T92W and L138F mutants showed enhanced intracellular Ca2+ sensitivity, which was normalized by re-adding STIM1 to the cells. Truncation of the Orai1 C-terminus reduced T92W CDI, indicating a key role for the Orai1 C-terminus for CDI. Overall, these results identify the molecular basis of a disease phenotype with broad implications for activation and inactivation of Orai1 channels.
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Affiliation(s)
| | - Megumi Yamashita
- Department of Pharmacology, Northwestern UniversityChicagoUnited States
| | - Murali Prakriya
- Department of Pharmacology, Northwestern UniversityChicagoUnited States
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6
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Jardin I, Berna-Erro A, Nieto-Felipe J, Macias A, Sanchez-Collado J, Lopez JJ, Salido GM, Rosado JA. Similarities and Differences between the Orai1 Variants: Orai1α and Orai1β. Int J Mol Sci 2022; 23:ijms232314568. [PMID: 36498894 PMCID: PMC9735889 DOI: 10.3390/ijms232314568] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2022] [Revised: 11/16/2022] [Accepted: 11/21/2022] [Indexed: 11/24/2022] Open
Abstract
Orai1, the first identified member of the Orai protein family, is ubiquitously expressed in the animal kingdom. Orai1 was initially characterized as the channel responsible for the store-operated calcium entry (SOCE), a major mechanism that allows cytosolic calcium concentration increments upon receptor-mediated IP3 generation, which results in intracellular Ca2+ store depletion. Furthermore, current evidence supports that abnormal Orai1 expression or function underlies several disorders. Orai1 is, together with STIM1, the key element of SOCE, conducting the Ca2+ release-activated Ca2+ (CRAC) current and, in association with TRPC1, the store-operated Ca2+ (SOC) current. Additionally, Orai1 is involved in non-capacitative pathways, as the arachidonate-regulated or LTC4-regulated Ca2+ channel (ARC/LRC), store-independent Ca2+ influx activated by the secretory pathway Ca2+-ATPase (SPCA2) and the small conductance Ca2+-activated K+ channel 3 (SK3). Furthermore, Orai1 possesses two variants, Orai1α and Orai1β, the latter lacking 63 amino acids in the N-terminus as compared to the full-length Orai1α form, which confers distinct features to each variant. Here, we review the current knowledge about the differences between Orai1α and Orai1β, the implications of the Ca2+ signals triggered by each variant, and their downstream modulatory effect within the cell.
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7
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PKC-Mediated Orai1 Channel Phosphorylation Modulates Ca2+ Signaling in HeLa Cells. Cells 2022; 11:cells11132037. [PMID: 35805121 PMCID: PMC9266177 DOI: 10.3390/cells11132037] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2022] [Revised: 05/15/2022] [Accepted: 05/27/2022] [Indexed: 12/04/2022] Open
Abstract
The overexpression of the Orai1 channel inhibits SOCE when using the Ca2+ readdition protocol. However, we found that HeLa cells overexpressing the Orai1 channel displayed enhanced Ca2+ entry and a limited ER depletion in response to the combination of ATP and thapsigargin (TG) in the presence of external Ca2+. As these effects require the combination of an agonist and TG, we decided to study whether the phosphorylation of Orai1 S27/S30 residues had any role using two different mutants: Orai1-S27/30A (O1-AA, phosphorylation-resistant) and Orai1-S27/30D (O1-DD, phosphomimetic). Both O1-wt and O1-AA supported enhanced Ca2+ entry, but this was not the case with O1-E106A (dead-pore mutant), O1-DD, and O1-AA-E106A, while O1-wt, O1-E106A, and O1-DD inhibited the ATP and TG-induced reduction of ER [Ca2+], suggesting that the phosphorylation of O1 S27/30 interferes with the IP3R activity. O1-wt and O1-DD displayed an increased interaction with IP3R in response to ATP and TG; however, the O1-AA channel decreased this interaction. The expression of mCherry-O1-AA increased the frequency of ATP-induced sinusoidal [Ca2+]i oscillations, while mCherry-O1-wt and mCherry-O1-DD decreased this frequency. These data suggest that the combination of ATP and TG stimulates Ca2+ entry, and the phosphorylation of Orai1 S27/30 residues by PKC reduces IP3R-mediated Ca2+ release.
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8
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Humer C, Romanin C, Höglinger C. Highlighting the Multifaceted Role of Orai1 N-Terminal- and Loop Regions for Proper CRAC Channel Functions. Cells 2022; 11:371. [PMID: 35159181 PMCID: PMC8834118 DOI: 10.3390/cells11030371] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2021] [Revised: 01/14/2022] [Accepted: 01/15/2022] [Indexed: 11/16/2022] Open
Abstract
Orai1, the Ca2+-selective pore in the plasma membrane, is one of the key components of the Ca2+release-activated Ca2+ (CRAC) channel complex. Activated by the Ca2+ sensor in the endoplasmic reticulum (ER) membrane, stromal interaction molecule 1 (STIM1), via direct interaction when ER luminal Ca2+ levels recede, Orai1 helps to maintain Ca2+ homeostasis within a cell. It has already been proven that the C-terminus of Orai1 is indispensable for channel activation. However, there is strong evidence that for CRAC channels to function properly and maintain all typical hallmarks, such as selectivity and reversal potential, additional parts of Orai1 are needed. In this review, we focus on these sites apart from the C-terminus; namely, the second loop and N-terminus of Orai1 and on their multifaceted role in the functioning of CRAC channels.
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Affiliation(s)
| | | | - Carmen Höglinger
- Institute of Biophysics, Johannes Kepler University Linz, Gruberstrasse 40, 4020 Linz, Austria; (C.H.); (C.R.)
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9
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Carreras-Sureda A, Abrami L, Ji-Hee K, Wang WA, Henry C, Frieden M, Didier M, van der Goot FG, Demaurex N. S-acylation by ZDHHC20 targets ORAI1 channels to lipid rafts for efficient Ca 2+ signaling by Jurkat T cell receptors at the immune synapse. eLife 2021; 10:72051. [PMID: 34913437 PMCID: PMC8683079 DOI: 10.7554/elife.72051] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2021] [Accepted: 11/29/2021] [Indexed: 12/29/2022] Open
Abstract
Efficient immune responses require Ca2+ fluxes across ORAI1 channels during engagement of T cell receptors (TCR) at the immune synapse (IS) between T cells and antigen presenting cells. Here, we show that ZDHHC20-mediated S-acylation of the ORAI1 channel at residue Cys143 promotes TCR recruitment and signaling at the IS. Cys143 mutations reduced ORAI1 currents and store-operated Ca2+ entry in HEK-293 cells and nearly abrogated long-lasting Ca2+ elevations, NFATC1 translocation, and IL-2 secretion evoked by TCR engagement in Jurkat T cells. The acylation-deficient channel remained in cholesterol-poor domains upon enforced ZDHHC20 expression and was recruited less efficiently to the IS along with actin and TCR. Our results establish S-acylation as a critical regulator of ORAI1 channel trafficking and function at the IS and reveal that ORAI1 S-acylation enhances TCR recruitment to the synapse.
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Affiliation(s)
| | - Laurence Abrami
- Faculty of Life Sciences, Global Health Institute, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Kim Ji-Hee
- Department of Physiology, Yonsei University Wonju College of Medicine, Wonju, Republic of Korea
| | - Wen-An Wang
- Department of Cell Physiology and Metabolism, Geneva, Switzerland
| | | | - Maud Frieden
- Department of Cell Physiology and Metabolism, Geneva, Switzerland
| | - Monica Didier
- Department of Cell Physiology and Metabolism, Geneva, Switzerland
| | - F Gisou van der Goot
- Faculty of Life Sciences, Global Health Institute, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Nicolas Demaurex
- Department of Cell Physiology and Metabolism, Geneva, Switzerland
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10
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Rychkov GY, Zhou FH, Adams MK, Brierley SM, Ma L, Barritt GJ. Orai1- and Orai2-, but not Orai3-mediated I CRAC is regulated by intracellular pH. J Physiol 2021; 600:623-643. [PMID: 34877682 DOI: 10.1113/jp282502] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2021] [Accepted: 11/25/2021] [Indexed: 12/12/2022] Open
Abstract
Three Orai (Orai1, Orai2, and Orai3) and two stromal interaction molecule (STIM1 and STIM2) mammalian protein homologues constitute major components of the store-operated Ca2+ entry mechanism. When co-expressed with STIM1, Orai1, Orai2 and Orai3 form highly selective Ca2+ channels with properties of Ca2+ release-activated Ca2+ (CRAC) channels. Despite the high level of homology between Orai proteins, CRAC channels formed by different Orai isoforms have distinctive properties, particularly with regards to Ca2+ -dependent inactivation, inhibition/potentiation by 2-aminoethyl diphenylborinate and sensitivity to reactive oxygen species. This study characterises and compares the regulation of Orai1, Orai2- and Orai3-mediated CRAC current (ICRAC ) by intracellular pH (pHi ). Using whole-cell patch clamping of HEK293T cells heterologously expressing Orai and STIM1, we show that ICRAC formed by each Orai homologue has a unique sensitivity to changes in pHi . Orai1-mediated ICRAC exhibits a strong dependence on pHi of both current amplitude and the kinetics of Ca2+ -dependent inactivation. In contrast, Orai2 amplitude, but not kinetics, depends on pHi , whereas Orai3 shows no dependence on pHi at all. Investigation of different Orai1-Orai3 chimeras suggests that pHi dependence of Orai1 resides in both the N-terminus and intracellular loop 2, and may also involve pH-dependent interactions with STIM1. KEY POINTS: It has been shown previously that Orai1/stromal interaction molecule 1 (STIM1)-mediated Ca2+ release-activated Ca2+ current (ICRAC ) is inhibited by intracellular acidification and potentiated by intracellular alkalinisation. The present study reveals that CRAC channels formed by each of the Orai homologues Orai1, Orai2 and Orai3 has a unique sensitivity to changes in intracellular pH (pHi ). The amplitude of Orai2 current is affected by the changes in pHi similarly to the amplitude of Orai1. However, unlike Orai1, fast Ca2+ -dependent inactivation of Orai2 is unaffected by acidic pHi . In contrast to both Orai1 and Orai2, Orai3 is not sensitive to pHi changes. Domain swapping between Orai1 and Orai3 identified the N-terminus and intracellular loop 2 as the molecular structures responsible for Orai1 regulation by pHi . Reduction of ICRAC dependence on pHi seen in a STIM1-independent Orai1 mutant suggested that some parts of STIM1 are also involved in ICRAC modulation by pHi .
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Affiliation(s)
- Grigori Y Rychkov
- School of Medicine, University of Adelaide, Adelaide, South Australia, Australia.,Hopwood Centre for Neurobiology, Lifelong Health Theme, South Australian Health and Medical Research Institute, Adelaide, South Australia, Australia
| | - Fiona H Zhou
- School of Medicine, University of Adelaide, Adelaide, South Australia, Australia.,Hopwood Centre for Neurobiology, Lifelong Health Theme, South Australian Health and Medical Research Institute, Adelaide, South Australia, Australia
| | - Melissa K Adams
- School of Medicine, University of Adelaide, Adelaide, South Australia, Australia.,Hopwood Centre for Neurobiology, Lifelong Health Theme, South Australian Health and Medical Research Institute, Adelaide, South Australia, Australia
| | - Stuart M Brierley
- School of Medicine, University of Adelaide, Adelaide, South Australia, Australia.,Hopwood Centre for Neurobiology, Lifelong Health Theme, South Australian Health and Medical Research Institute, Adelaide, South Australia, Australia.,Visceral Pain Research Group, College of Medicine and Public Health, Flinders Health and Medical Research Institute (FHMRI), Flinders University, Bedford Park, South Australia, Australia
| | - Linlin Ma
- College of Medicine and Public Health, Flinders University of South Australia, Bedford Park, South Australia, Australia.,Griffith Institute for Drug Discovery, Griffith University, Nathan, Queensland, Australia
| | - Greg J Barritt
- College of Medicine and Public Health, Flinders University of South Australia, Bedford Park, South Australia, Australia
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11
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Conformational surveillance of Orai1 by a rhomboid intramembrane protease prevents inappropriate CRAC channel activation. Mol Cell 2021; 81:4784-4798.e7. [PMID: 34800360 PMCID: PMC8657799 DOI: 10.1016/j.molcel.2021.10.025] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2020] [Revised: 06/14/2021] [Accepted: 10/26/2021] [Indexed: 12/19/2022]
Abstract
Calcium influx through plasma membrane calcium release-activated calcium (CRAC) channels, which are formed of hexamers of Orai1, is a potent trigger for many important biological processes, most notably in T cell-mediated immunity. Through a bioinformatics-led cell biological screen, we have identified Orai1 as a substrate for the rhomboid intramembrane protease RHBDL2. We show that RHBDL2 prevents stochastic calcium signaling in unstimulated cells through conformational surveillance and cleavage of inappropriately activated Orai1. A conserved disease-linked proline residue is responsible for RHBDL2’s recognizing the active conformation of Orai1, which is required to sharpen switch-like signaling triggered by store-operated calcium entry. Loss of RHBDL2 control of CRAC channel activity causes severe dysregulation of downstream CRAC channel effectors, including transcription factor activation, inflammatory cytokine expression, and T cell activation. We propose that this surveillance function may represent an ancient activity of rhomboid proteases in degrading unwanted signaling proteins. A screen for transmembrane substrates of the rhomboid intramembrane protease RHBDL2 RHBDL2 cleaves the CRAC channel protein Orai1 when it is inappropriately activated Conformational change in these calcium channels is recognized by RHBDL2 An Orai1 mutant that cannot be cleaved by RHBDL2 causes a human disease syndrome
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12
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Dynes JL, Yeromin AV, Cahalan MD. Cell-wide mapping of Orai1 channel activity reveals functional heterogeneity in STIM1-Orai1 puncta. J Gen Physiol 2021; 152:151900. [PMID: 32589186 PMCID: PMC7478869 DOI: 10.1085/jgp.201812239] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2018] [Revised: 12/11/2019] [Accepted: 05/21/2020] [Indexed: 12/16/2022] Open
Abstract
Upon Ca2+ store depletion, Orai1 channels cluster and open at endoplasmic reticulum–plasma membrane (ER–PM) junctions in signaling complexes called puncta. Little is known about whether and how Orai1 channel activity may vary between individual puncta. Previously, we developed and validated optical recording of Orai channel activity, using genetically encoded Ca2+ indicators fused to Orai1 or Orai3 N or C termini. We have now combined total internal reflection fluorescence microscopy with whole-cell recording to map functional properties of channels at individual puncta. After Ca2+ store depletion in HEK cells cotransfected with mCherry-STIM1 and Orai1-GCaMP6f, Orai1-GCaMP6f fluorescence increased progressively with increasingly negative test potentials and robust responses could be recorded from individual puncta. Cell-wide fluorescence half-rise and -fall times during steps to −100 mV test potential indicated probe response times of <50 ms. The in situ Orai1-GCaMP6f affinity for Ca2+ was 620 nM, assessed by monitoring fluorescence using buffered Ca2+ solutions in “unroofed” cells. Channel activity and temporal activation profile were tracked in individual puncta using image maps and automated puncta identification and recording. Simultaneous measurement of mCherry-STIM1 fluorescence uncovered an unexpected gradient in STIM1/Orai1 ratio that extends across the cell surface. Orai1-GCaMP6f channel activity was found to vary across the cell, with inactive channels occurring in the corners of cells where the STIM1/Orai1 ratio was lowest; low-activity channels typically at edges displayed a slow activation phase lasting hundreds of milliseconds. Puncta with high STIM1/Orai1 ratios exhibited a range of channel activity that appeared unrelated to the stoichiometric requirements for gating. These findings demonstrate functional heterogeneity of Orai1 channel activity between individual puncta and establish a new experimental platform that facilitates systematic comparisons between puncta composition and activity.
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Affiliation(s)
- Joseph L Dynes
- Department of Physiology and Biophysics, University of California at Irvine School of Medicine, Irvine, CA
| | - Andriy V Yeromin
- Department of Physiology and Biophysics, University of California at Irvine School of Medicine, Irvine, CA
| | - Michael D Cahalan
- Department of Physiology and Biophysics, University of California at Irvine School of Medicine, Irvine, CA.,Institute for Immunology, University of California, Irvine, Irvine, CA
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13
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Baraniak JH, Zhou Y, Nwokonko RM, Jennette MR, Kazzaz SA, Stenson JM, Whitsell AL, Wang Y, Trebak M, Gill DL. Orai channel C-terminal peptides are key modulators of STIM-Orai coupling and calcium signal generation. Cell Rep 2021; 35:109322. [PMID: 34192542 PMCID: PMC8462482 DOI: 10.1016/j.celrep.2021.109322] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2020] [Revised: 03/17/2021] [Accepted: 06/07/2021] [Indexed: 11/03/2022] Open
Abstract
Junctional coupling between endoplasmic reticulum (ER) Ca2+-sensor STIM proteins and plasma membrane (PM) Orai channels mediates Ca2+ signals in most cells. We reveal that PM-tethered, fluorescently tagged C-terminal M4x (fourth transmembrane helix contains a cytoplasmic C-terminal extension) peptides from Orai channels undergo a Leu-specific signature of direct interaction with the STIM1 Orai-activating region (SOAR), exactly mimicking STIM1 binding to gate Orai channels. The 20-amino-acid Orai3-M4x peptide associates avidly with STIM1 within ER-PM junctions, functions to competitively block native Ca2+ signals, and mediates a key modification of STIM-Orai coupling induced by 2-aminoethoxydiphenyl borate. By blocking STIM-Orai coupling, the Orai3-M4x peptide reveals the critical role of Orai channels in driving Ca2+ oscillatory signals and transcriptional control through NFAT. The M4x peptides interact independently with SOAR dimers consistent with unimolecular coupling between Orai subunits and STIM1 dimers. We reveal the critical role of M4x helices in defining the coupling interface between STIM and Orai proteins to mediate store-operated Ca2+ signals.
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Affiliation(s)
- James H Baraniak
- Department of Cellular and Molecular Physiology, The Pennsylvania State University College of Medicine, Hershey, PA 17033, USA
| | - Yandong Zhou
- Department of Cellular and Molecular Physiology, The Pennsylvania State University College of Medicine, Hershey, PA 17033, USA.
| | - Robert M Nwokonko
- Department of Cellular and Molecular Physiology, The Pennsylvania State University College of Medicine, Hershey, PA 17033, USA
| | - Michelle R Jennette
- Department of Cellular and Molecular Physiology, The Pennsylvania State University College of Medicine, Hershey, PA 17033, USA
| | - Sarah A Kazzaz
- Department of Cellular and Molecular Physiology, The Pennsylvania State University College of Medicine, Hershey, PA 17033, USA
| | - Jazmin M Stenson
- Department of Cellular and Molecular Physiology, The Pennsylvania State University College of Medicine, Hershey, PA 17033, USA
| | - Abigale L Whitsell
- Department of Cellular and Molecular Physiology, The Pennsylvania State University College of Medicine, Hershey, PA 17033, USA
| | - Youjun Wang
- Beijing Key Laboratory of Gene Resources and Molecular Development College of Life Sciences, Beijing Normal University, Beijing 100875, People's Republic of China
| | - Mohamed Trebak
- Department of Cellular and Molecular Physiology, The Pennsylvania State University College of Medicine, Hershey, PA 17033, USA
| | - Donald L Gill
- Department of Cellular and Molecular Physiology, The Pennsylvania State University College of Medicine, Hershey, PA 17033, USA.
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14
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Shalygin A, Kolesnikov D, Glushankova L, Gusev K, Skopin A, Skobeleva K, Kaznacheyeva EV. Role of STIM2 and Orai proteins in regulating TRPC1 channel activity upon calcium store depletion. Cell Calcium 2021; 97:102432. [PMID: 34157631 DOI: 10.1016/j.ceca.2021.102432] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2020] [Revised: 05/08/2021] [Accepted: 06/04/2021] [Indexed: 11/17/2022]
Abstract
Store-operated calcium channels are the major player in calcium signaling in non-excitable cells. Store-operated calcium entry is associated with the Orai, stromal interaction molecule (STIM), and transient receptor potential canonical (TRPC) protein families. Researchers have provided conflicting data about TRPC1 channel regulation by Orai and STIM. To determine how Orai and STIM influence endogenous TRPC1 pore properties and regulation, we used single channel patch-clamp recordings. Here we showed that knockout or knockdown of Orai1 or Orai3 or overexpression of the dominant-negative mutant Orai1 E106Q did not change the conductance or selectivity of single TRPC1 channels. In addition, these TRPC1 channel properties did not depend on the amount of STIM1 and STIM2 proteins. To study STIM2-mediated regulation of TRPC1 channels, we utilized partial calcium store depletion induced by application of 10 nM thapsigargin (Tg). TRPC1 activation by endogenous STIM2 was greatly decreased in acute extracellular calcium-free experiments. STIM2 overexpression increased both the basal activity and number of silent TRPC1 channels in the plasma membrane. After calcium store depletion, overexpressed STIM2 directly activated TRPC1 in the plasma membrane even without calcium entry in acute experiments. However, this effect was abrogated by co-expression with the non-permeable Orai1 E106Q mutant protein. Taken together, our single-channel patch clamp experiments clearly demonstrated that endogenous TRPC1 forms a channel pore without involving Orai proteins. Calcium entry through Orai triggered TRPC1 channel activation in the plasma membrane, while subsequent STIM2-mediated TRPC1 activity regulation was not dependent on calcium entry.
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Affiliation(s)
- A Shalygin
- Institute of Cytology, Russian Academy of Sciences, 4 Tikhoretsky Avenue, St. Petersburg 194064, Russia.
| | - D Kolesnikov
- Institute of Cytology, Russian Academy of Sciences, 4 Tikhoretsky Avenue, St. Petersburg 194064, Russia
| | - L Glushankova
- Institute of Cytology, Russian Academy of Sciences, 4 Tikhoretsky Avenue, St. Petersburg 194064, Russia
| | - K Gusev
- Institute of Cytology, Russian Academy of Sciences, 4 Tikhoretsky Avenue, St. Petersburg 194064, Russia
| | - A Skopin
- Institute of Cytology, Russian Academy of Sciences, 4 Tikhoretsky Avenue, St. Petersburg 194064, Russia
| | - K Skobeleva
- Institute of Cytology, Russian Academy of Sciences, 4 Tikhoretsky Avenue, St. Petersburg 194064, Russia
| | - E V Kaznacheyeva
- Institute of Cytology, Russian Academy of Sciences, 4 Tikhoretsky Avenue, St. Petersburg 194064, Russia.
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15
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Alemán OR, Mora N, Rosales C. The Antibody Receptor Fc Gamma Receptor IIIb Induces Calcium Entry via Transient Receptor Potential Melastatin 2 in Human Neutrophils. Front Immunol 2021; 12:657393. [PMID: 34054821 PMCID: PMC8155622 DOI: 10.3389/fimmu.2021.657393] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2021] [Accepted: 04/23/2021] [Indexed: 11/13/2022] Open
Abstract
Human neutrophils express two unique antibody receptors for IgG, the FcγRIIa and the FcγRIIIb. FcγRIIa contains an immunoreceptor tyrosine-based activation motif (ITAM) sequence within its cytoplasmic tail, which is important for initiating signaling. In contrast, FcγRIIIb is a glycosylphosphatidylinositol (GPI)-linked receptor with no cytoplasmic tail. Although, the initial signaling mechanism for FcγRIIIb remains unknown, it is clear that both receptors are capable of initiating distinct neutrophil cellular functions. For example, FcγRIIa is known to induce an increase in L-selectin expression and efficient phagocytosis, while FcγRIIIb does not promote these responses. In contrast, FcγRIIIb has been reported to induce actin polymerization, activation of β1 integrins, and formation of neutrophils extracellular traps (NET) much more efficiently than FcγRIIa. Another function where these receptors seem to act differently is the increase of cytoplasmic calcium concentration. It has been known for a long time that FcγRIIa induces production of inositol triphosphate (IP3) to release calcium from intracellular stores, while FcγRIIIb does not use this phospholipid. Thus, the mechanism for FcγRIIIb-mediated calcium rise remains unknown. Transient Receptor Potential Melastatin 2 (TRPM2) is a calcium permeable channel expressed in many cell types including vascular smooth cells, endothelial cells and leukocytes. TRPM2 can be activated by protein kinase C (PKC) and by oxidative stress. Because we previously found that FcγRIIIb stimulation leading to NET formation involves PKC activation and reactive oxygen species (ROS) production, in this report we explored whether TRPM2 is activated via FcγRIIIb and mediates calcium rise in human neutrophils. Calcium rise was monitored after Fcγ receptors were stimulated by specific monoclonal antibodies in Fura-2-loaded neutrophils. The bacterial peptide fMLF and FcγRIIa induced a calcium rise coming initially from internal pools. In contrast, FcγRIIIb caused a calcium rise by inducing calcium entry from the extracellular medium. In addition, in the presence of 2-aminoethoxydiphenyl borate (2-APB) or of clotrimazole, two inhibitors of TRPM2, FcγRIIIb-induced calcium rise was blocked. fMLF- or FcγRIIa-induced calcium rise was not affected by these inhibitors. These data suggest for the first time that FcγRIIIb aggregation activates TRPM2, to induce an increase in cytoplasmic calcium concentration through calcium internalization in human neutrophils.
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Affiliation(s)
- Omar Rafael Alemán
- Departamento de Inmunología, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - Nancy Mora
- Departamento de Inmunología, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - Carlos Rosales
- Departamento de Inmunología, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Mexico City, Mexico
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16
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Wong HSC, Chang WC. Single-cell melanoma transcriptomes depicting functional versatility and clinical implications of STIM1 in the tumor microenvironment. Am J Cancer Res 2021; 11:5092-5106. [PMID: 33859736 PMCID: PMC8039943 DOI: 10.7150/thno.54134] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2020] [Accepted: 12/06/2020] [Indexed: 12/31/2022] Open
Abstract
Rationale: Previous studies have implicated the functions of stromal interaction molecule 1 (STIM1) in immunity and malignancy, however, the specificity and effects of STIM1 expression in malignant and non-malignant cells in the tumor microenvironment are unclear. Methods: In the current study, we posed two central questions: (1) does STIM1 expression elicit different cellular programs in cell types within the melanoma tumor microenvironment (2) whether the expression of STIM1 and STIM1-coexpressed genes (SCGs) serve as prognostic indicators of patient's outcomes? To answer these questions, we dissected cell-specific STIM1-associated cellular programs in diverse cell types within the melanoma tumor microenvironment by measuring cell-type specificity of STIM1 expression and SCGs. Results: A distinct set of SCGs was highly affected in malignant melanoma cells, but not in the other cell types, suggesting the existence of malignant-cell-specific cellular programs reflected by STIM1 expression. In contrast to malignant cells, STIM1 expression appeared to trigger universal and non-specific biological functions in non-malignant cell types, as exemplified by the transcriptomes of macrophages and CD4+ T regulatory cells. Results from bioinformatic analyses indicated that SCGs in malignant cells may alter cell-cell interactions through cytokine/chemokine signaling and/or orchestrate immune infiltration into the tumor. Moreover, a prognostic association between SCGs in CD4+ T regulatory cells and patient's outcomes was identified. However, we didn't find any correlation between SCGs and responsiveness of immunotherapy. Conclusions: Overall, our results provide an integrated biological framework for understanding the functional and clinical consequences of cell-specific STIM1 expression in melanoma.
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Supra-Molecular Assemblies of ORAI1 at Rest Precede Local Accumulation into Puncta after Activation. Int J Mol Sci 2021; 22:ijms22020799. [PMID: 33466866 PMCID: PMC7831003 DOI: 10.3390/ijms22020799] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2020] [Revised: 01/04/2021] [Accepted: 01/12/2021] [Indexed: 12/13/2022] Open
Abstract
The Ca2+ selective channel ORAI1 and endoplasmic reticulum (ER)-resident STIM proteins form the core of the channel complex mediating store operated Ca2+ entry (SOCE). Using liquid phase electron microscopy (LPEM), the distribution of ORAI1 proteins was examined at rest and after SOCE-activation at nanoscale resolution. The analysis of over seven hundred thousand ORAI1 positions revealed a number of ORAI1 channels had formed STIM-independent distinct supra-molecular clusters. Upon SOCE activation and in the presence of STIM proteins, a fraction of ORAI1 assembled in micron-sized two-dimensional structures, such as the known puncta at the ER plasma membrane contact zones, but also in divergent structures such as strands, and ring-like shapes. Our results thus question the hypothesis that stochastically migrating single ORAI1 channels are trapped at regions containing activated STIM, and we propose instead that supra-molecular ORAI1 clusters fulfill an amplifying function for creating dense ORAI1 accumulations upon SOCE-activation.
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18
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The Orai Pore Opening Mechanism. Int J Mol Sci 2021; 22:ijms22020533. [PMID: 33430308 PMCID: PMC7825772 DOI: 10.3390/ijms22020533] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2020] [Revised: 12/30/2020] [Accepted: 01/02/2021] [Indexed: 02/07/2023] Open
Abstract
Cell survival and normal cell function require a highly coordinated and precise regulation of basal cytosolic Ca2+ concentrations. The primary source of Ca2+ entry into the cell is mediated by the Ca2+ release-activated Ca2+ (CRAC) channel. Its action is stimulated in response to internal Ca2+ store depletion. The fundamental constituents of CRAC channels are the Ca2+ sensor, stromal interaction molecule 1 (STIM1) anchored in the endoplasmic reticulum, and a highly Ca2+-selective pore-forming subunit Orai1 in the plasma membrane. The precise nature of the Orai1 pore opening is currently a topic of intensive research. This review describes how Orai1 gating checkpoints in the middle and cytosolic extended transmembrane regions act together in a concerted manner to ensure an opening-permissive Orai1 channel conformation. In this context, we highlight the effects of the currently known multitude of Orai1 mutations, which led to the identification of a series of gating checkpoints and the determination of their role in diverse steps of the Orai1 activation cascade. The synergistic action of these gating checkpoints maintains an intact pore geometry, settles STIM1 coupling, and governs pore opening. We describe the current knowledge on Orai1 channel gating mechanisms and summarize still open questions of the STIM1-Orai1 machinery.
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19
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Le Guilcher C, Luyten T, Parys JB, Pucheault M, Dellis O. Synthesis and Characterization of Store-Operated Calcium Entry Inhibitors Active in the Submicromolar Range. Int J Mol Sci 2020; 21:ijms21249777. [PMID: 33371518 PMCID: PMC7767506 DOI: 10.3390/ijms21249777] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2020] [Revised: 12/09/2020] [Accepted: 12/18/2020] [Indexed: 12/13/2022] Open
Abstract
The store-operated calcium entry, better known as SOCE, forms the main Ca2+ influx pathway in non-excitable cells, especially in leukocytes, where it is required for cell activation and the immune response. During the past decades, several inhibitors were developed, but they lack specificity or efficacy. From the non-specific SOCE inhibitor 2-aminoethyl diphenylborinate (2-APB), we synthetized 16 new analogues by replacing/modifying the phenyl groups. Among them, our compound P11 showed the best inhibitory capacity with a Ki ≈ 75 nM. Furthermore, below 1 µM, P11 was devoid of any inhibitory activity on the two other main cellular targets of 2-APB, the IP3 receptors, and the SERCA pumps. Interestingly, Jurkat T cells secrete interleukin-2 under phytohemagglutinin stimulation but undergo cell death and stop IL-2 synthesis when stimulated in the presence of increasing P11 concentrations. Thus, P11 could represent the first member of a new and potent family of immunosuppressors.
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Affiliation(s)
- Camille Le Guilcher
- Physiopathogénèse et Traitements des Maladies du Foie, Université Paris-Saclay, Rue des Adeles, 91405 Orsay, France;
- INSERM U1193, Rue des Adeles, 91405 Orsay, France
| | - Tomas Luyten
- Laboratory for Molecular and Cellular Signaling, Department of Cellular and Molecular Medicine & Leuven Kanker Instituut, B-3000 Leuven, Belgium; (T.L.); (J.B.P.)
| | - Jan B. Parys
- Laboratory for Molecular and Cellular Signaling, Department of Cellular and Molecular Medicine & Leuven Kanker Instituut, B-3000 Leuven, Belgium; (T.L.); (J.B.P.)
| | - Mathieu Pucheault
- Institute of Molecular Science, CNRS, Université de Bordeaux, 33400 Talence, France;
| | - Olivier Dellis
- Physiopathogénèse et Traitements des Maladies du Foie, Université Paris-Saclay, Rue des Adeles, 91405 Orsay, France;
- INSERM U1193, Rue des Adeles, 91405 Orsay, France
- Correspondence: ; Tel.: +33-169-154-959
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20
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The short isoform of extended synaptotagmin-2 controls Ca 2+ dynamics in T cells via interaction with STIM1. Sci Rep 2020; 10:14433. [PMID: 32879390 PMCID: PMC7468131 DOI: 10.1038/s41598-020-71489-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2020] [Accepted: 08/14/2020] [Indexed: 11/16/2022] Open
Abstract
Ca2+ release-activated Ca2+ (CRAC) channels elevate cytoplasmic Ca2+ concentration, which is essential for T cell activation, differentiation and effector functions. T cell receptor stimulation induces depletion of the endoplasmic reticulum (ER) Ca2+ stores, which is sensed by stromal interaction molecule 1 (STIM1). STIM1 translocates to the ER-plasma membrane (PM) junctions to interact with ORAI1, the pore subunit of the CRAC channels. Here, we show that two members of the extended synaptotagmin (E-Syt) family, E-Syt1, and the short isoform of E-Syt2 (E-Syt2S), contribute to activation of CRAC channels in T cells. Knockdown or deletion of both ESYT1 and ESYT2 reduced store-operated Ca2+ entry (SOCE) and ORAI1-STIM1 clustering in Jurkat T cells. Further, depletion of E-Syts in primary T cells decreased Ca2+ entry and cytokine production. While the ER-PM junctions were reduced in both HeLa and Jurkat T cells deleted for ESYT1 and ESYT2, SOCE was impaired only in Jurkat T cells, suggesting that the membrane-tethering function of E-Syts is distinct from their role in SOCE. Mechanistically, E-Syt2S, the predominant isoform of E-Syt2 in T cells, recruited STIM1 to the junctions via a direct interaction. This study demonstrates a membrane-tethering-independent role of E-Syts in activation of CRAC channels in T cells.
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21
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Gavali JT, Carrillo ED, García MC, Sánchez JA. The mitochondrial K-ATP channel opener diazoxide upregulates STIM1 and Orai1 via ROS and the MAPK pathway in adult rat cardiomyocytes. Cell Biosci 2020; 10:96. [PMID: 32817784 PMCID: PMC7424994 DOI: 10.1186/s13578-020-00460-w] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2020] [Accepted: 08/07/2020] [Indexed: 11/15/2022] Open
Abstract
Background Openers of mitochondrial adenosine triphosphate-dependent potassium (mKATP) channels like diazoxide increase reactive oxygen species (ROS) production in cardiac cells and reduce Ca2+ elevations produced by ischemia–reperfusion, protecting the heart from damage. In this study we tested the hypothesis that opening mKATP channels regulates expression of the major components of store-operated Ca2+ entry (SOCE) STIM1 and Orai1. Results Quantitative reverse transcriptase polymerase chain reaction (qRT-PCR) and western blot experiments showed that diazoxide increased expression of STIM1 and Orai1 at the mRNA and protein levels, respectively, in adult rat cardiomyocytes. Immunofluorescence analyses revealed that diazoxide also disrupted the striated distribution pattern of STIM1. These effects were prevented by the ROS scavenger N-acetyl cysteine (NAC), the mKATP channel antagonist 5-hydroxydecanoate (5-HD), or the protein synthesis inhibitor cycloheximide (CHX). Confocal microscopy revealed that diazoxide also led to nuclear translocation of the transcription factors c-Fos and NFκB, which was also blocked by NAC or 5-HD. Finally, the MAPK pathway inhibitor UO126 attenuated diazoxide-induced upregulation of STIM1 and Orai1 expression. Conclusions Our results suggest that opening mitochondrial potassium ATP channels with diazoxide upregulates the expression of STIM1 and Orai1 by de novo synthesis by a mechanism that involves NFkB, c-Fos, and ROS via MAPK/ERK signaling.
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Affiliation(s)
- Joice T Gavali
- Departamento de Farmacología, Centro de Investigación y de Estudios Avanzados del IPN, Av. Instituto Politécnico Nacional 2508, 07360 Ciudad de México, CDMX Mexico
| | - Elba D Carrillo
- Departamento de Farmacología, Centro de Investigación y de Estudios Avanzados del IPN, Av. Instituto Politécnico Nacional 2508, 07360 Ciudad de México, CDMX Mexico
| | - María C García
- Departamento de Farmacología, Centro de Investigación y de Estudios Avanzados del IPN, Av. Instituto Politécnico Nacional 2508, 07360 Ciudad de México, CDMX Mexico
| | - Jorge A Sánchez
- Departamento de Farmacología, Centro de Investigación y de Estudios Avanzados del IPN, Av. Instituto Politécnico Nacional 2508, 07360 Ciudad de México, CDMX Mexico
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22
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Baraniak JH, Zhou Y, Nwokonko RM, Gill DL. The Intricate Coupling Between STIM Proteins and Orai Channels. CURRENT OPINION IN PHYSIOLOGY 2020; 17:106-114. [PMID: 32954113 DOI: 10.1016/j.cophys.2020.07.018] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Store-operated Ca2+ entry signals are critical for cellular regulation. This intricate signaling pathway involves coupling of proteins in two different membranes: the ER-resident Ca2+-sensing STIM proteins and the highly Ca2+-selective PM Orai channels. The molecular nature of the STIM-Orai coupling interface in ER-PM junctions and consequent Orai channel gating, are processes under intense study. We describe recent developments in determining the mechanism of Orai activation through the key STIM-Orai Activating Region (SOAR) of STIM1. We describe the unexpected unimolecular coupling of STIM with Orai and explain the observed variable stoichiometry of STIM-Orai interactions. We also define the discrete C-terminal regions in Orai channels that initially latch onto STIM proteins and mediate allosteric activation of the channel. A critical "nexus" region closely associated with the STIM-activated C-terminus of Orai1, propagates the STIM-binding signal through the four tightly-associated transmembrane helices of Orai1, finally to modify the pore-forming helices and effect channel opening.
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Affiliation(s)
- James H Baraniak
- Department of Cellular and Molecular Physiology, The Pennsylvania State University College of Medicine, Hershey, PA 17033
| | - Yandong Zhou
- Department of Cellular and Molecular Physiology, The Pennsylvania State University College of Medicine, Hershey, PA 17033
| | - Robert M Nwokonko
- Department of Cellular and Molecular Physiology, The Pennsylvania State University College of Medicine, Hershey, PA 17033
| | - Donald L Gill
- Department of Cellular and Molecular Physiology, The Pennsylvania State University College of Medicine, Hershey, PA 17033
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23
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Abstract
Ca2+ is a ubiquitous and dynamic second messenger molecule that is induced by many factors including receptor activation, environmental factors, and voltage, leading to pleiotropic effects on cell function including changes in migration, metabolism and transcription. As such, it is not surprising that aberrant regulation of Ca2+ signals can lead to pathological phenotypes, including cancer progression. However, given the highly context-specific nature of Ca2+-dependent changes in cell function, delineation of its role in cancer has been a challenge. Herein, we discuss the distinct roles of Ca2+ signaling within and between each type of cancer, including consideration of the potential of therapeutic strategies targeting these signaling pathways.
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Affiliation(s)
- Scott Gross
- Fels Institute for Cancer Research and Molecular Biology, Lewis Katz School of Medicine at Temple University, Philadelphia, PA, United States
| | - Pranava Mallu
- Fels Institute for Cancer Research and Molecular Biology, Lewis Katz School of Medicine at Temple University, Philadelphia, PA, United States
| | - Hinal Joshi
- Fels Institute for Cancer Research and Molecular Biology, Lewis Katz School of Medicine at Temple University, Philadelphia, PA, United States
| | - Bryant Schultz
- Fels Institute for Cancer Research and Molecular Biology, Lewis Katz School of Medicine at Temple University, Philadelphia, PA, United States
| | - Christina Go
- Fels Institute for Cancer Research and Molecular Biology, Lewis Katz School of Medicine at Temple University, Philadelphia, PA, United States
| | - Jonathan Soboloff
- Fels Institute for Cancer Research and Molecular Biology, Lewis Katz School of Medicine at Temple University, Philadelphia, PA, United States; Department of Medical Genetics & Molecular Biochemistry, Lewis Katz School of Medicine at Temple University, Philadelphia, PA, United States.
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24
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Store-Operated Calcium Channels: From Function to Structure and Back Again. Cold Spring Harb Perspect Biol 2020; 12:cshperspect.a035055. [PMID: 31570335 DOI: 10.1101/cshperspect.a035055] [Citation(s) in RCA: 75] [Impact Index Per Article: 18.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Store-operated calcium (Ca2+) entry (SOCE) occurs through a widely distributed family of ion channels activated by the loss of Ca2+ from the endoplasmic reticulum (ER). The best understood of these is the Ca2+ release-activated Ca2+ (CRAC) channel, which is notable for its unique activation mechanism as well as its many essential physiological functions and the diverse pathologies that result from dysregulation. In response to ER Ca2+ depletion, CRAC channels are formed through a diffusion trap mechanism at ER-plasma membrane (PM) junctions, where the ER Ca2+-sensing stromal interaction molecule (STIM) proteins bind and activate hexamers of Orai pore-forming proteins to trigger Ca2+ entry. Cell biological studies are clarifying the architecture of ER-PM junctions, their roles in Ca2+ and lipid transport, and functional interactions with cytoskeletal proteins. Molecular structures of STIM and Orai have inspired a multitude of mutagenesis and electrophysiological studies that reveal potential mechanisms for how STIM is toggled between inactive and active states, how it binds and activates Orai, and the importance of STIM-binding stoichiometry for opening the channel and establishing its signature characteristics of extremely high Ca2+ selectivity and low Ca2+ conductance.
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25
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Kappel S, Kilch T, Baur R, Lochner M, Peinelt C. The Number and Position of Orai3 Units within Heteromeric Store-Operated Ca 2+ Channels Alter the Pharmacology of I CRAC. Int J Mol Sci 2020; 21:ijms21072458. [PMID: 32252254 PMCID: PMC7178029 DOI: 10.3390/ijms21072458] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2020] [Revised: 03/24/2020] [Accepted: 03/30/2020] [Indexed: 12/21/2022] Open
Abstract
Store-operated heteromeric Orai1/Orai3 channels have been discussed in the context of aging, cancer, and immune cell differentiation. In contrast to homomeric Orai1 channels, they exhibit a different pharmacology upon application of reactive oxygen species (ROS) or 2-aminoethoxydiphenyl borate (2-APB) in various cell types. In endogenous cells, subunit composition and arrangement may vary and cannot be defined precisely. In this study, we used patch-clamp electrophysiology to investigate the 2-APB profile of store-operated and store-independent homomeric Orai1 and heteromeric Orai1/Orai3 concatenated channels with defined subunit compositions. As has been shown previous, one or more Orai3 subunit(s) within the channel result(s) in decreased Ca2+ release activated Ca2+ current (ICRAC). Upon application of 50 µM 2-APB, channels with two or more Orai3 subunits exhibit large outward currents and can be activated by 2-APB independent from storedepletion and/or the presence of STIM1. The number and position of Orai3 subunits within the heteromeric store-operated channel change ion conductivity of 2-APB-activated outward current. Compared to homomeric Orai1 channels, one Orai3 subunit within the channel does not alter 2-APB pharmacology. None of the concatenated channel constructs were able to exactly simulate the complex 2-APB pharmacology observed in prostate cancer cells. However, 2-APB profiles of prostate cancer cells are similar to those of concatenated channels with Orai3 subunit(s). Considering the presented and previous results, this indicates that distinct subtypes of heteromeric SOCE channels may be selectively activated or blocked. In the future, targeting distinct heteromeric SOCE channel subtypes may be the key to tailored SOCE-based therapies.
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Affiliation(s)
- Sven Kappel
- Institute of Biochemistry and Molecular Medicine, University of Bern, Bühlstrasse 28, 3012 Bern, Switzerland; (S.K.); (R.B.); (M.L.)
| | | | - Roland Baur
- Institute of Biochemistry and Molecular Medicine, University of Bern, Bühlstrasse 28, 3012 Bern, Switzerland; (S.K.); (R.B.); (M.L.)
| | - Martin Lochner
- Institute of Biochemistry and Molecular Medicine, University of Bern, Bühlstrasse 28, 3012 Bern, Switzerland; (S.K.); (R.B.); (M.L.)
| | - Christine Peinelt
- Institute of Biochemistry and Molecular Medicine, University of Bern, Bühlstrasse 28, 3012 Bern, Switzerland; (S.K.); (R.B.); (M.L.)
- Correspondence: ; Tel.: +41-31-631-3415
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Dyrda A, Koenig S, Frieden M. STIM1 long and STIM1 gate differently TRPC1 during store-operated calcium entry. Cell Calcium 2020; 86:102134. [DOI: 10.1016/j.ceca.2019.102134] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2019] [Revised: 11/13/2019] [Accepted: 11/25/2019] [Indexed: 11/30/2022]
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Angenendt A, Steiner R, Knörck A, Schwär G, Konrad M, Krause E, Lis A. Orai, STIM, and PMCA contribute to reduced calcium signal generation in CD8 + T cells of elderly mice. Aging (Albany NY) 2020; 12:3266-3286. [PMID: 32062611 PMCID: PMC7066920 DOI: 10.18632/aging.102809] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2019] [Accepted: 01/24/2020] [Indexed: 12/22/2022]
Abstract
Ca2+ is a crucial second messenger for proper T cell function. Considering the relevance of Ca2+ signals for T cell functionality it is surprising that no mechanistic insights into T cell Ca2+ signals from elderly individuals are reported. The main Ca2+ entry mechanism in T cells are STIM-activated Orai channels. Their role during lymphocyte aging is completely unknown. Here, we report not only reduced Ca2+ signals in untouched and stimulated, but also in central and effector memory CD8+ T cells from elderly (18-24 months) compared to adult (3-6 months) mice. Two mechanisms contribute to the overall reduction in Ca2+ signals of CD8+ T cells of elderly mice: 1) Reduced Ca2+ currents through Orai channels due to decreased expressions of STIMs and Orais. 2) A faster extrusion of Ca2+ owing to an increased expression of PMCA4. The reduced Ca2+ signals correlated with a resistance of the cytotoxic efficiency of CD8+ T cells to varying free [Ca2+]ext with age. In summary, reduced STIM/Orai expression and increased Ca2+ clearing rates following enhanced PMCA4 expression contribute to reduced Ca2+ signals in CD8+ T cells of elderly mice. These changes are apparently relevant to immune function as they reduce the Ca2+ dependency of CTL cytotoxicity.
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Affiliation(s)
- Adrian Angenendt
- Biophysics, Center for Integrative Physiology and Molecular Medicine, School of Medicine, Saarland University, Homburg 66421, Germany
| | - Romy Steiner
- Biophysics, Center for Integrative Physiology and Molecular Medicine, School of Medicine, Saarland University, Homburg 66421, Germany.,Present address: Section of Transplantation Immunology, Department of Surgery, Medical University of Vienna, Vienna 1090, Austria
| | - Arne Knörck
- Biophysics, Center for Integrative Physiology and Molecular Medicine, School of Medicine, Saarland University, Homburg 66421, Germany
| | - Gertrud Schwär
- Biophysics, Center for Integrative Physiology and Molecular Medicine, School of Medicine, Saarland University, Homburg 66421, Germany
| | - Maik Konrad
- Molecular Biophysics, Center for Integrative Physiology and Molecular Medicine, School of Medicine, Saarland University, Homburg 66421, Germany
| | - Elmar Krause
- Cellular Neurophysiology, Center for Integrative Physiology and Molecular Medicine, School of Medicine, Saarland University, Homburg 66421, Germany
| | - Annette Lis
- Biophysics, Center for Integrative Physiology and Molecular Medicine, School of Medicine, Saarland University, Homburg 66421, Germany
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TRPC Channels in the SOCE Scenario. Cells 2020; 9:cells9010126. [PMID: 31948094 PMCID: PMC7016597 DOI: 10.3390/cells9010126] [Citation(s) in RCA: 51] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2019] [Revised: 12/29/2019] [Accepted: 12/31/2019] [Indexed: 11/29/2022] Open
Abstract
Transient receptor potential (TRP) proteins form non-selective Ca2+ permeable channels that contribute to the modulation of a number of physiological functions in a variety of cell types. Since the identification of TRP proteins in Drosophila, it is well known that these channels are activated by stimuli that induce PIP2 hydrolysis. The canonical TRP (TRPC) channels have long been suggested to be constituents of the store-operated Ca2+ (SOC) channels; however, none of the TRPC channels generate Ca2+ currents that resemble ICRAC. STIM1 and Orai1 have been identified as the components of the Ca2+ release-activated Ca2+ (CRAC) channels and there is a body of evidence supporting that STIM1 is able to gate Orai1 and TRPC1 in order to mediate non-selective cation currents named ISOC. STIM1 has been found to interact to and activate Orai1 and TRPC1 by different mechanisms and the involvement of TRPC1 in store-operated Ca2+ entry requires both STIM1 and Orai1. In addition to the participation of TRPC1 in the ISOC currents, TRPC1 and other TRPC proteins might play a relevant role modulating Orai1 channel function. This review summarizes the functional role of TRPC channels in the STIM1–Orai1 scenario.
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Butorac C, Krizova A, Derler I. Review: Structure and Activation Mechanisms of CRAC Channels. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2020; 1131:547-604. [PMID: 31646526 DOI: 10.1007/978-3-030-12457-1_23] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Ca2+ release activated Ca2+ (CRAC) channels represent a primary pathway for Ca2+ to enter non-excitable cells. The two key players in this process are the stromal interaction molecule (STIM), a Ca2+ sensor embedded in the membrane of the endoplasmic reticulum, and Orai, a highly Ca2+ selective ion channel located in the plasma membrane. Upon depletion of the internal Ca2+ stores, STIM is activated, oligomerizes, couples to and activates Orai. This review provides an overview of novel findings about the CRAC channel activation mechanisms, structure and gating. In addition, it highlights, among diverse STIM and Orai mutants, also the disease-related mutants and their implications.
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Affiliation(s)
- Carmen Butorac
- Institute of Biophysics, Johannes Kepler University of Linz, Linz, Austria
| | - Adéla Krizova
- Institute of Biophysics, Johannes Kepler University of Linz, Linz, Austria
| | - Isabella Derler
- Institute of Biophysics, Johannes Kepler University of Linz, Linz, Austria.
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Ashmore J, Olsen H, Sørensen N, Thrasivoulou C, Ahmed A. Wnts control membrane potential in mammalian cancer cells. J Physiol 2019; 597:5899-5914. [DOI: 10.1113/jp278661] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2019] [Accepted: 10/23/2019] [Indexed: 01/30/2023] Open
Affiliation(s)
- Jonathan Ashmore
- Department of Neuroscience Physiology and Pharmacology and UCL Ear Institute University College London Gower Street London WC1E 6BT UK
| | - Hervør Olsen
- Sophion Bioscience A/S Baltorpvej 154 DK‐2750 Ballerup Denmark
| | - Naja Sørensen
- Sophion Bioscience A/S Baltorpvej 154 DK‐2750 Ballerup Denmark
| | - Christopher Thrasivoulou
- Research Department of Cell & Developmental Biology, Centre for Cell & Molecular Dynamics, Rockefeller Building University Street, University College London London WC1E 6JJ UK
| | - Aamir Ahmed
- Centre for Stem Cells and Regenerative Medicine King's College London, 28th Floor, Tower Wing, Guy's Hospital Great Maze Pond London SE1 9RT UK
- Prostate Cancer Research Centre, Division of Surgery, 3rd Floor Laboratories, Charles Bell House University College London 67 Riding House Street London W1W 7EJ UK
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Karacicek B, Erac Y, Tosun M. Functional consequences of enhanced expression of STIM1 and Orai1 in Huh-7 hepatocellular carcinoma tumor-initiating cells. BMC Cancer 2019; 19:751. [PMID: 31366337 PMCID: PMC6668110 DOI: 10.1186/s12885-019-5947-z] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2019] [Accepted: 07/16/2019] [Indexed: 12/18/2022] Open
Abstract
Background The endoplasmic reticulum (ER) Ca2+ sensor, stromal interaction molecule1 (STIM1) activates the plasma membrane (PM) channel Orai1 in order to mediate store-operated Ca2+ entry (SOCE) in response to ER store depletion. Enhanced expression of STIM1 in cancer tissue has been associated with poor patient prognosis. Therefore, this study investigated the functional consequences of enhanced expression of STIM1 and Orai1 in a tumor-initiating subpopulation of Huh-7 hepatocellular carcinoma (HCC) cells that express epithelial cell adhesion molecule (EpCAM) and Prominin 1 (CD133). Methods We performed qRT-PCR, intracellular Ca2+ monitoring, protein analyses, and real-time cell proliferation assays on EpCAM(+)CD133(+) subpopulation of tumor-initiating Huh-7 HCC cells expressing high levels of STIM1 and/or Orai1. Statistical significance between the means of two groups was evaluated using unpaired Student’s t-test. Results Enhanced STIM1 expression significantly increased ER Ca2+ release and proliferation rate of EpCAM(+)CD133(+) cells. Conclusion STIM1 overexpression may facilitate cancer cell survival by increasing ER Ca2+-buffering capacity, which makes more Ca2+ available for the cytosolic events, on the other hand, possibly preventing Ca2+-dependent enzymatic activity in mitochondria whose Ca2+ uniporter requires much higher cytosolic Ca2+ levels.
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Affiliation(s)
- B Karacicek
- Izmir Biomedicine and Genome Center (IBG), Dokuz Eylul University, 35340, Izmir, Turkey
| | - Y Erac
- Department of Pharmacology, Faculty of Pharmacy, Ege University, 35100, Izmir, Turkey
| | - M Tosun
- Department of Pharmacology, School of Medicine, Izmir University of Economics, 35330, Izmir, Turkey.
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Krizova A, Maltan L, Derler I. Critical parameters maintaining authentic CRAC channel hallmarks. EUROPEAN BIOPHYSICS JOURNAL : EBJ 2019; 48:425-445. [PMID: 30903264 PMCID: PMC6647248 DOI: 10.1007/s00249-019-01355-6] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/15/2018] [Revised: 12/20/2018] [Accepted: 03/06/2019] [Indexed: 12/20/2022]
Abstract
Ca2+ ions represent versatile second messengers that regulate a huge diversity of processes throughout the cell's life. One prominent Ca2+ entry pathway into the cell is the Ca2+ release-activated Ca2+ (CRAC) ion channel. It is fully reconstituted by the two molecular key players: the stromal interaction molecule (STIM1) and Orai. STIM1 is a Ca2+ sensor located in the membrane of the endoplasmic reticulum, and Orai, a highly Ca2+ selective ion channel embedded in the plasma membrane. Ca2+ store-depletion leads initially to the activation of STIM1 which subsequently activates Orai channels via direct binding. Authentic CRAC channel hallmarks and biophysical characteristics include high Ca2+ selectivity with a reversal potential in the range of + 50 mV, small unitary conductance, fast Ca2+-dependent inactivation and enhancements in currents upon the switch from a Na+-containing divalent-free to a Ca2+-containing solution. This review provides an overview on the critical determinants and structures within the STIM1 and Orai proteins that establish these prominent CRAC channel characteristics.
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Affiliation(s)
- Adéla Krizova
- Institute of Biophysics, Johannes Kepler University of Linz, Gruberstrasse 40, 4020, Linz, Austria
| | - Lena Maltan
- Institute of Biophysics, Johannes Kepler University of Linz, Gruberstrasse 40, 4020, Linz, Austria
| | - Isabella Derler
- Institute of Biophysics, Johannes Kepler University of Linz, Gruberstrasse 40, 4020, Linz, Austria.
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Yeung PSW, Yamashita M, Prakriya M. Molecular basis of allosteric Orai1 channel activation by STIM1. J Physiol 2019; 598:1707-1723. [PMID: 30950063 DOI: 10.1113/jp276550] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2018] [Accepted: 03/19/2019] [Indexed: 12/13/2022] Open
Abstract
Store-operated Ca2+ entry through Orai1 channels is a primary mechanism for Ca2+ entry in many cells and mediates numerous cellular effector functions ranging from gene transcription to exocytosis. Orai1 channels are amongst the most Ca2+ -selective channels known and are activated by direct physical interactions with the endoplasmic reticulum Ca2+ sensor stromal interaction molecule 1 (STIM1) in response to store depletion triggered by stimulation of a variety of cell surface G-protein coupled and tyrosine kinase receptors. Work in the last decade has revealed that the Orai1 gating process is highly cooperative and strongly allosteric, likely driven by a wave of interdependent conformational changes throughout the protein originating in the peripheral C-terminal ligand binding site and culminating in pore opening. In this review, we survey the structural and molecular features in Orai1 that contribute to channel gating and consider how they give rise to the unique biophysical fingerprint of Orai1 currents.
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Affiliation(s)
- Priscilla See-Wai Yeung
- Department of Pharmacology, Northwestern University, Feinberg School of Medicine, Chicago, IL, 60611, USA
| | - Megumi Yamashita
- Department of Pharmacology, Northwestern University, Feinberg School of Medicine, Chicago, IL, 60611, USA
| | - Murali Prakriya
- Department of Pharmacology, Northwestern University, Feinberg School of Medicine, Chicago, IL, 60611, USA
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A calcium/cAMP signaling loop at the ORAI1 mouth drives channel inactivation to shape NFAT induction. Nat Commun 2019; 10:1971. [PMID: 31036819 PMCID: PMC6488650 DOI: 10.1038/s41467-019-09593-0] [Citation(s) in RCA: 62] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2018] [Accepted: 03/20/2019] [Indexed: 02/06/2023] Open
Abstract
ORAI1 constitutes the store-operated Ca2+ release-activated Ca2+ (CRAC) channel crucial for life. Whereas ORAI1 activation by Ca2+-sensing STIM proteins is known, still obscure is how ORAI1 is turned off through Ca2+-dependent inactivation (CDI), protecting against Ca2+ toxicity. Here we identify a spatially-restricted Ca2+/cAMP signaling crosstalk critical for mediating CDI. Binding of Ca2+-activated adenylyl cyclase 8 (AC8) to the N-terminus of ORAI1 positions AC8 near the mouth of ORAI1 for sensing Ca2+. Ca2+ permeating ORAI1 activates AC8 to generate cAMP and activate PKA. PKA, positioned by AKAP79 near ORAI1, phosphorylates serine-34 in ORAI1 pore extension to induce CDI whereas recruitment of the phosphatase calcineurin antagonizes the effect of PKA. Notably, CDI shapes ORAI1 cytosolic Ca2+ signature to determine the isoform and degree of NFAT activation. Thus, we uncover a mechanism of ORAI1 inactivation, and reveal a hitherto unappreciated role for inactivation in shaping cellular Ca2+ signals and NFAT activation. ORAI1 constitutes the store-operated Ca2+ release-activated Ca2+ (CRAC) channel, but how this channel is turned off through Ca2+-dependent inactivation (CDI) remained unclear. Here the authors identify a spatially-restricted Ca2+/cAMP signaling crosstalk critical for mediating CDI which in turn regulates cellular Ca2+ signals and NFAT activation.
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Frisch J, Angenendt A, Hoth M, Prates Roma L, Lis A. STIM-Orai Channels and Reactive Oxygen Species in the Tumor Microenvironment. Cancers (Basel) 2019; 11:E457. [PMID: 30935064 PMCID: PMC6520831 DOI: 10.3390/cancers11040457] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2019] [Revised: 03/22/2019] [Accepted: 03/27/2019] [Indexed: 02/06/2023] Open
Abstract
The tumor microenvironment (TME) is shaped by cancer and noncancerous cells, the extracellular matrix, soluble factors, and blood vessels. Interactions between the cells, matrix, soluble factors, and blood vessels generate this complex heterogeneous microenvironment. The TME may be metabolically beneficial or unbeneficial for tumor growth, it may favor or not favor a productive immune response against tumor cells, or it may even favor conditions suited to hijacking the immune system for benefitting tumor growth. Soluble factors relevant for TME include oxygen, reactive oxygen species (ROS), ATP, Ca2+, H⁺, growth factors, or cytokines. Ca2+ plays a prominent role in the TME because its concentration is directly linked to cancer cell proliferation, apoptosis, or migration but also to immune cell function. Stromal-interaction molecules (STIM)-activated Orai channels are major Ca2+ entry channels in cancer cells and immune cells, they are upregulated in many tumors, and they are strongly regulated by ROS. Thus, STIM and Orai are interesting candidates to regulate cancer cell fate in the TME. In this review, we summarize the current knowledge about the function of ROS and STIM/Orai in cancer cells; discuss their interdependencies; and propose new hypotheses how TME, ROS, and Orai channels influence each other.
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Affiliation(s)
- Janina Frisch
- Department of Biophysics, Center for Integrative Physiology and Molecular Medicine, Medical Faculty, Saarland University, 66421 Homburg, Germany.
- Center for Human and Molecular Biology, Saarland University, 66421 Homburg, Germany.
| | - Adrian Angenendt
- Department of Biophysics, Center for Integrative Physiology and Molecular Medicine, Medical Faculty, Saarland University, 66421 Homburg, Germany.
| | - Markus Hoth
- Department of Biophysics, Center for Integrative Physiology and Molecular Medicine, Medical Faculty, Saarland University, 66421 Homburg, Germany.
| | - Leticia Prates Roma
- Department of Biophysics, Center for Integrative Physiology and Molecular Medicine, Medical Faculty, Saarland University, 66421 Homburg, Germany.
- Center for Human and Molecular Biology, Saarland University, 66421 Homburg, Germany.
| | - Annette Lis
- Department of Biophysics, Center for Integrative Physiology and Molecular Medicine, Medical Faculty, Saarland University, 66421 Homburg, Germany.
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Cantonero C, Sanchez-Collado J, Gonzalez-Nuñez MA, Salido GM, Lopez JJ, Jardin I, Rosado JA. Store-independent Orai1-mediated Ca 2+ entry and cancer. Cell Calcium 2019; 80:1-7. [PMID: 30921687 DOI: 10.1016/j.ceca.2019.02.012] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2019] [Revised: 02/28/2019] [Accepted: 02/28/2019] [Indexed: 12/22/2022]
Abstract
Ca2+ channels play an important role in the development of different types of cancer, and considerable progress has been made to understand the pathophysiological mechanisms underlying the role of Ca2+ influx in the development of different cancer hallmarks. Orai1 is among the most ubiquitous and multifunctional Ca2+ channels. Orai1 mediates the highly Ca2+-selective Ca2+ release-activated current (ICRAC) and participates in the less Ca2+-selective store-operated current (ISOC), along with STIM1 or STIM1 and TRPC1, respectively. Furthermore, Orai1 contributes to a variety of store-independent Ca2+ influx mechanisms, including the arachidonate-regulated Ca2+ current, together with Orai3 and the plasma membrane resident pool of STIM1, as well as the constitutive Ca2+ influx processes activated by the secretory pathway Ca2+-ATPase-2 (SPCA2) or supported by physical and functional interaction with the small conductance Ca2+-activated K+ channel 3 (SK3) or the voltage-dependent Kv10.1 channel. This review summarizes the current knowledge concerning the store-independent mechanisms of Ca2+ influx activation through Orai1 channels and their role in the development of different cancer features.
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Affiliation(s)
- C Cantonero
- Cellular Physiology Research Group, Department of Physiology, Institute of Molecular Pathology Biomarkers, University of Extremadura, 10003 Caceres, Spain
| | - J Sanchez-Collado
- Cellular Physiology Research Group, Department of Physiology, Institute of Molecular Pathology Biomarkers, University of Extremadura, 10003 Caceres, Spain
| | - M A Gonzalez-Nuñez
- Pathology Service, Hospital San Pedro de Alcantara, 10003 Cáceres, Spain
| | - G M Salido
- Cellular Physiology Research Group, Department of Physiology, Institute of Molecular Pathology Biomarkers, University of Extremadura, 10003 Caceres, Spain
| | - J J Lopez
- Cellular Physiology Research Group, Department of Physiology, Institute of Molecular Pathology Biomarkers, University of Extremadura, 10003 Caceres, Spain
| | - I Jardin
- Cellular Physiology Research Group, Department of Physiology, Institute of Molecular Pathology Biomarkers, University of Extremadura, 10003 Caceres, Spain
| | - J A Rosado
- Cellular Physiology Research Group, Department of Physiology, Institute of Molecular Pathology Biomarkers, University of Extremadura, 10003 Caceres, Spain.
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Schmidt B, Alansary D, Bogeski I, Niemeyer BA, Rieger H. Reaction-diffusion model for STIM-ORAI interaction: The role of ROS and mutations. J Theor Biol 2019; 470:64-75. [PMID: 30853394 DOI: 10.1016/j.jtbi.2019.02.010] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2018] [Revised: 02/13/2019] [Accepted: 02/18/2019] [Indexed: 11/30/2022]
Abstract
Release of Ca2+ from endoplasmatic retriculum (ER) Ca2+ stores causes stromal interaction molecules (STIM) in the ER membrane and ORAI proteins in the plasma membrane (PM) to interact and form the Ca2+ release activated Ca2+ (CRAC) channels, which represent a major Ca2+ entry route in non-excitable cells and thus control various cell functions. It is experimentally possible to mutate ORAI1 proteins and therefore modify, especially block, the Ca2+ influx into the cell. On the basis of the model of Hoover and Lewis (2011), we formulate a reaction-diffusion model to quantify the STIM1-ORAI1 interaction during CRAC channel formation and analyze different ORAI1 channel stoichiometries and different ratios of STIM1 and ORAI1 in comparison with experimental data. We incorporate the inhibition of ORAI1 channels by ROS into our model and calculate its contribution to the CRAC channel amplitude. We observe a large decrease of the CRAC channel amplitude evoked by mutations of ORAI1 proteins.
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Affiliation(s)
- Barbara Schmidt
- Center for Biophysics & Department of Theoretical Physics, Saarland University, Saarbrücken 66041, Germany; Department of Molecular Biophysics, Center for Integrative Physiology and Molecular Medicine, Saarland University, Homburg 66421, Germany; Department of Biophysics, Center for Integrative Physiology and Molecular Medicine, Saarland University, Homburg 66421, Germany.
| | - Dalia Alansary
- Department of Molecular Biophysics, Center for Integrative Physiology and Molecular Medicine, Saarland University, Homburg 66421, Germany.
| | - Ivan Bogeski
- Department of Biophysics, Center for Integrative Physiology and Molecular Medicine, Saarland University, Homburg 66421, Germany; Molecular Physiology, Institute of Cardiovascular Physiology, University Medical Center Georg-August-University, Göttingen 37073, Germany.
| | - Barbara A Niemeyer
- Department of Molecular Biophysics, Center for Integrative Physiology and Molecular Medicine, Saarland University, Homburg 66421, Germany.
| | - Heiko Rieger
- Center for Biophysics & Department of Theoretical Physics, Saarland University, Saarbrücken 66041, Germany.
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Heterologous calcium-dependent inactivation of Orai1 by neighboring TRPV1 channels modulates cell migration and wound healing. Commun Biol 2019; 2:88. [PMID: 30854480 PMCID: PMC6399350 DOI: 10.1038/s42003-019-0338-1] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2018] [Accepted: 02/05/2019] [Indexed: 02/06/2023] Open
Abstract
Store-operated calcium entry (SOCE) is an essential calcium influx mechanism in animal cells. One of the most important auto regulatory control systems involves calcium-dependent inactivation (CDI) of the Orai channel, which prevents excessive calcium influx. In the present study we analyze the role of two channels in the induction of CDI on Orai1. Here we show that calcium entering through freely diffusing TRPV1 channels induce strong CDI on Orai1 while calcium entering through P2X4 channel does not. TRPV1 can induce CDI on Orai1 because both channels were found in close proximity in the cell membrane. This was not observed with P2X4 channels. To our knowledge, this is the first study demonstrating that calcium arising from different channels may contribute to the modulation of Orai1 through CDI in freely diffusing single channels of living cells. Our results highlight the role of TRPV1-mediated CDI on Orai1 in cell migration and wound healing. Bastián-Eugenio et al. showed that calcium entering the cell via TRPV1, but not P2X4 channels, can induce calcium-dependent inactivation of Orai1. This inactivation impacts thrombin-induced cell migration and wound healing suggesting an important role of Orai1 modulation by TRPV1 channels.
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Yen M, Lewis RS. Numbers count: How STIM and Orai stoichiometry affect store-operated calcium entry. Cell Calcium 2019; 79:35-43. [PMID: 30807904 DOI: 10.1016/j.ceca.2019.02.002] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2018] [Revised: 02/06/2019] [Accepted: 02/06/2019] [Indexed: 02/06/2023]
Abstract
Substantial progress has been made in the past several years in establishing the stoichiometries of STIM and Orai proteins and understanding their influence on store-operated calcium entry. Depletion of ER Ca2+ triggers STIM1 to accumulate at ER-plasma membrane junctions where it binds and opens Ca2+ release-activated Ca2+ (CRAC) channels. STIM1 is a dimer, and release of Ca2+ from its two luminal domains is reported to promote their association as well as drive formation of higher-order STIM1 oligomers. The CRAC channel, originally thought to be tetrameric, is now considered to be a hexamer of Orai1 subunits based on crystallographic and electrophysiological studies. STIM1 binding activates CRAC channels in a highly nonlinear way, such that all six Orai1 binding sites must be occupied to account for the activation and signature properties of native channels. The structural basis of STIM1 engagement with the channel is currently unclear, with evidence suggesting that STIM1 dimers bind to individual or pairs of Orai1 subunits. This review examines evidence that has led to points of consensus and debate about STIM1 and Orai1 stoichiometries, and explains the importance of STIM-Orai complex stoichiometry for the regulation of store-operated calcium entry.
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Affiliation(s)
- Michelle Yen
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, CA, 94305, United States
| | - Richard S Lewis
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, CA, 94305, United States.
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Lunz V, Romanin C, Frischauf I. STIM1 activation of Orai1. Cell Calcium 2019; 77:29-38. [PMID: 30530091 DOI: 10.1016/j.ceca.2018.11.009] [Citation(s) in RCA: 65] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2018] [Revised: 11/20/2018] [Accepted: 11/28/2018] [Indexed: 11/23/2022]
Abstract
A primary calcium (Ca2+) entry pathway into non-excitable cells is through the store-operated Ca2+ release activated Ca2+ (CRAC) channel. Ca2+ entry into cells is responsible for the initiation of diverse signalling cascades that affect essential cellular processes like gene regulation, cell growth and death, secretion and gene transcription. Upon depletion of intracellular Ca2+ stores within the endoplasmic reticulum (ER), the CRAC channel opens to refill depleted stores. The two key limiting molecular players of the CRAC channel are the stromal interaction molecule (STIM1) embedded in the ER-membrane and Orai1, residing in the plasma membrane (PM), respectively. Together, they form a highly Ca2+ selective ion channel complex. STIM1 senses the Ca2+ content of the ER and confers Ca2+ store-depletion into the opening of Orai1 channels in the PM for triggering Ca2+-dependent gene transcription, T-cell activation or mast cell degranulation. The interplay of Orai and STIM proteins in the CRAC channel signalling cascade has been the main focus of research for more than twelve years. This chapter focuses on current knowledge and main experimental advances in the understanding of Orai1 activation by STIM1, thereby portraying key mechanistic steps in the CRAC channel signalling cascade.
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Affiliation(s)
- Victoria Lunz
- Institute of Biophysics, Johannes Kepler University Linz, A-4020, Linz, Austria
| | - Christoph Romanin
- Institute of Biophysics, Johannes Kepler University Linz, A-4020, Linz, Austria.
| | - Irene Frischauf
- Institute of Biophysics, Johannes Kepler University Linz, A-4020, Linz, Austria.
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41
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Jardin I, Lopez JJ, Salido GM, Rosado JA. Store-Operated Ca 2+ Entry in Breast Cancer Cells: Remodeling and Functional Role. Int J Mol Sci 2018; 19:ijms19124053. [PMID: 30558192 PMCID: PMC6321005 DOI: 10.3390/ijms19124053] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2018] [Revised: 12/03/2018] [Accepted: 12/11/2018] [Indexed: 12/22/2022] Open
Abstract
Breast cancer is the most common type of cancer in women. It is a heterogeneous disease that ranges from the less undifferentiated luminal A to the more aggressive basal or triple negative breast cancer molecular subtype. Ca2+ influx from the extracellular medium, but more specifically store-operated Ca2+ entry (SOCE), has been reported to play an important role in tumorigenesis and the maintenance of a variety of cancer hallmarks, including cell migration, proliferation, invasion or epithelial to mesenchymal transition. Breast cancer cells remodel the expression and functional role of the molecular components of SOCE. This review focuses on the functional role and remodeling of SOCE in breast cancer cells. The current studies suggest the need to deepen our understanding of SOCE in the biology of the different breast cancer subtypes in order to develop new and specific therapeutic strategies.
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Affiliation(s)
- Isaac Jardin
- Department of Physiology, (Cellular Physiology Research Group), Institute of Molecular Pathology Biomarkers, University of Extremadura, 10003 Caceres, Spain.
| | - Jose J Lopez
- Department of Physiology, (Cellular Physiology Research Group), Institute of Molecular Pathology Biomarkers, University of Extremadura, 10003 Caceres, Spain.
| | - Gines M Salido
- Department of Physiology, (Cellular Physiology Research Group), Institute of Molecular Pathology Biomarkers, University of Extremadura, 10003 Caceres, Spain.
| | - Juan A Rosado
- Department of Physiology, (Cellular Physiology Research Group), Institute of Molecular Pathology Biomarkers, University of Extremadura, 10003 Caceres, Spain.
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Schober R, Waldherr L, Schmidt T, Graziani A, Stilianu C, Legat L, Groschner K, Schindl R. STIM1 and Orai1 regulate Ca 2+ microdomains for activation of transcription. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2018; 1866:1079-1091. [PMID: 30408546 DOI: 10.1016/j.bbamcr.2018.11.001] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/30/2018] [Revised: 10/31/2018] [Accepted: 11/01/2018] [Indexed: 02/07/2023]
Abstract
Since calcium (Ca2+) regulates a large variety of cellular signaling processes in a cell's life, precise control of Ca2+ concentrations within the cell is essential. This enables the transduction of information via Ca2+ changes in a time-dependent and spatially defined manner. Here, we review molecular and functional aspects of how the store-operated Ca2+ channel Orai1 creates spatiotemporal Ca2+ microdomains. The architecture of this channel is unique, with a long helical pore and a six-fold symmetry. Energetic barriers within the Ca2+ channel pathway limit permeation to allow an extensive local Ca2+ increase in close proximity to the channel. The precise timing of the Orai1 channel function is controlled by direct binding to STIM proteins upon Ca2+ depletion in the endoplasmic reticulum. These induced Ca2+ microdomains are tailored to, and sufficient for, triggering long-term activation processes, such as transcription factor activation and subsequent gene regulation. We describe the principles of spatiotemporal activation of the transcription factor NFAT and compare its signaling characteristics to those of the autophagy regulating transcription factors, MITF and TFEB.
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Affiliation(s)
- Romana Schober
- Institute for Biophysics, Johannes Kepler University Linz, A-4040 Linz, Austria.
| | - Linda Waldherr
- Gottfried Schatz Research Center, Medical University of Graz, A-8010 Graz, Austria
| | - Tony Schmidt
- Gottfried Schatz Research Center, Medical University of Graz, A-8010 Graz, Austria
| | - Annarita Graziani
- Gottfried Schatz Research Center, Medical University of Graz, A-8010 Graz, Austria
| | - Clemens Stilianu
- Gottfried Schatz Research Center, Medical University of Graz, A-8010 Graz, Austria
| | - Lorenz Legat
- Gottfried Schatz Research Center, Medical University of Graz, A-8010 Graz, Austria
| | - Klaus Groschner
- Gottfried Schatz Research Center, Medical University of Graz, A-8010 Graz, Austria
| | - Rainer Schindl
- Gottfried Schatz Research Center, Medical University of Graz, A-8010 Graz, Austria.
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43
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Riva B, Griglio A, Serafini M, Cordero-Sanchez C, Aprile S, Di Paola R, Gugliandolo E, Alansary D, Biocotino I, Lim D, Grosa G, Galli U, Niemeyer B, Sorba G, Canonico PL, Cuzzocrea S, Genazzani AA, Pirali T. Pyrtriazoles, a Novel Class of Store-Operated Calcium Entry Modulators: Discovery, Biological Profiling, and in Vivo Proof-of-Concept Efficacy in Acute Pancreatitis. J Med Chem 2018; 61:9756-9783. [PMID: 30347159 DOI: 10.1021/acs.jmedchem.8b01512] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
In recent years, channels that mediate store-operated calcium entry (SOCE, i.e., the ability of cells to sense a decrease in endoplasmic reticulum luminal calcium and induce calcium entry across the plasma membrane) have been associated with a number of disorders, spanning from immune disorders to acute pancreatitis and have been suggested to be druggable targets. In the present contribution, we exploited the click chemistry approach to synthesize a class of SOCE modulators where the arylamide substructure that characterizes most inhibitors so far described is substituted by a 1,4-disubstituted 1,2,3-triazole ring. Within this series, inhibitors of SOCE were identified and the best compound proved effective in an animal model of acute pancreatitis, a disease characterized by a hyperactivation of SOCE. Strikingly, two enhancers of the process were discovered, affording invaluable research tools to further explore the (patho)physiological role of capacitative calcium entry.
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Affiliation(s)
- Beatrice Riva
- Department of Pharmaceutical Sciences , Università del Piemonte Orientale , Novara 28100 , Italy.,ChemICare Srl , Enne3 , Novara 28100 , Italy
| | - Alessia Griglio
- Department of Pharmaceutical Sciences , Università del Piemonte Orientale , Novara 28100 , Italy
| | - Marta Serafini
- Department of Pharmaceutical Sciences , Università del Piemonte Orientale , Novara 28100 , Italy
| | - Celia Cordero-Sanchez
- Department of Pharmaceutical Sciences , Università del Piemonte Orientale , Novara 28100 , Italy
| | - Silvio Aprile
- Department of Pharmaceutical Sciences , Università del Piemonte Orientale , Novara 28100 , Italy
| | - Rosanna Di Paola
- Department of Chemical, Biological, Pharmaceutical, and Enviromental Sciences , Università di Messina , Messina 98166 , Italy
| | - Enrico Gugliandolo
- Department of Chemical, Biological, Pharmaceutical, and Enviromental Sciences , Università di Messina , Messina 98166 , Italy
| | - Dalia Alansary
- Department of Molecular Biophysics , Saarland University CIPMM , Homburg 66421 , Germany
| | - Isabella Biocotino
- Department of Pharmaceutical Sciences , Università del Piemonte Orientale , Novara 28100 , Italy
| | - Dmitry Lim
- Department of Pharmaceutical Sciences , Università del Piemonte Orientale , Novara 28100 , Italy
| | - Giorgio Grosa
- Department of Pharmaceutical Sciences , Università del Piemonte Orientale , Novara 28100 , Italy
| | - Ubaldina Galli
- Department of Pharmaceutical Sciences , Università del Piemonte Orientale , Novara 28100 , Italy
| | - Barbara Niemeyer
- Department of Molecular Biophysics , Saarland University CIPMM , Homburg 66421 , Germany
| | - Giovanni Sorba
- Department of Pharmaceutical Sciences , Università del Piemonte Orientale , Novara 28100 , Italy
| | - Pier Luigi Canonico
- Department of Pharmaceutical Sciences , Università del Piemonte Orientale , Novara 28100 , Italy
| | - Salvatore Cuzzocrea
- Department of Chemical, Biological, Pharmaceutical, and Enviromental Sciences , Università di Messina , Messina 98166 , Italy
| | - Armando A Genazzani
- Department of Pharmaceutical Sciences , Università del Piemonte Orientale , Novara 28100 , Italy
| | - Tracey Pirali
- Department of Pharmaceutical Sciences , Università del Piemonte Orientale , Novara 28100 , Italy.,ChemICare Srl , Enne3 , Novara 28100 , Italy
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Yen M, Lewis RS. Physiological CRAC channel activation and pore properties require STIM1 binding to all six Orai1 subunits. J Gen Physiol 2018; 150:1373-1385. [PMID: 30120197 PMCID: PMC6168240 DOI: 10.1085/jgp.201711985] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2017] [Revised: 06/08/2018] [Accepted: 07/30/2018] [Indexed: 11/22/2022] Open
Abstract
The quantitative relation between STIM1 binding to Orai1 and store-operated CRAC channel activation is not well understood. Yen and Lewis find that STIM1 must bind to all six Orai1 subunits to effectively open the channel and generate the high ion selectivity and low conductance seen in native cells. The binding of STIM1 to Orai1 controls the opening of store-operated CRAC channels as well as their extremely high Ca2+ selectivity. Although STIM1 dimers are known to bind directly to the cytosolic C termini of the six Orai1 subunits (SUs) that form the channel hexamer, the dependence of channel activation and selectivity on the number of occupied binding sites is not well understood. Here we address these questions using dimeric and hexameric Orai1 concatemers in which L273D mutations were introduced to inhibit STIM1 binding to specific Orai1 SUs. By measuring FRET between fluorescently labeled STIM1 and Orai1, we find that homomeric L273D mutant channels fail to bind STIM1 appreciably; however, the L273D SU does bind STIM1 and contribute to channel activation when located adjacent to a WT SU. These results suggest that STIM1 dimers can interact with pairs of neighboring Orai1 SUs. Surprisingly, a single L273D mutation within the Orai1 hexamer reduces channel open probability by ∼90%, triples the size of the single-channel current, weakens the Ca2+ binding affinity of the selectivity filter, and lowers the selectivity for Na+ over Cs+ in the absence of divalent cations. These findings reveal a surprisingly strong functional coupling between STIM1 binding and CRAC channel gating and pore properties. We conclude that under physiological conditions, all six Orai1 SUs of the native CRAC channel bind STIM1 to effectively open the pore and generate the signature properties of extremely low conductance and high ion selectivity.
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Affiliation(s)
- Michelle Yen
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, CA
| | - Richard S Lewis
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, CA
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45
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Mapping the functional anatomy of Orai1 transmembrane domains for CRAC channel gating. Proc Natl Acad Sci U S A 2018; 115:E5193-E5202. [PMID: 29760086 DOI: 10.1073/pnas.1718373115] [Citation(s) in RCA: 45] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Store-operated Orai1 channels are activated through a unique inside-out mechanism involving binding of the endoplasmic reticulum Ca2+ sensor STIM1 to cytoplasmic sites on Orai1. Although atomic-level details of Orai structure, including the pore and putative ligand binding domains, are resolved, how the gating signal is communicated to the pore and opens the gate is unknown. To address this issue, we used scanning mutagenesis to identify 15 residues in transmembrane domains (TMs) 1-4 whose perturbation activates Orai1 channels independently of STIM1. Cysteine accessibility analysis and molecular-dynamics simulations indicated that constitutive activation of the most robust variant, H134S, arises from a pore conformational change that opens a hydrophobic gate to augment pore hydration, similar to gating evoked by STIM1. Mutational analysis of this locus suggests that H134 acts as steric brake to stabilize the closed state of the channel. In addition, atomic packing analysis revealed distinct functional contacts between the TM1 pore helix and the surrounding TM2/3 helices, including one set mediated by a cluster of interdigitating hydrophobic residues and another by alternative ridges of polar and hydrophobic residues. Perturbing these contacts via mutagenesis destabilizes STIM1-mediated Orai1 channel gating, indicating that these bridges between TM1 and the surrounding TM2/3 ring are critical for conveying the gating signal to the pore. These findings help develop a framework for understanding the global conformational changes and allosteric interactions between topologically distinct domains that are essential for activation of Orai1 channels.
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46
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Tsvilovskyy V, Solís-López A, Schumacher D, Medert R, Roers A, Kriebs U, Freichel M. Deletion of Orai2 augments endogenous CRAC currents and degranulation in mast cells leading to enhanced anaphylaxis. Cell Calcium 2018; 71:24-33. [DOI: 10.1016/j.ceca.2017.11.004] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2017] [Revised: 11/05/2017] [Accepted: 11/26/2017] [Indexed: 12/25/2022]
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47
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Zhang L, Chao CH, Jaeger LA, Papp AB, Machaty Z. Calcium oscillations in fertilized pig oocytes are associated with repetitive interactions between STIM1 and ORAI1. Biol Reprod 2018; 98:510-519. [PMID: 29365044 PMCID: PMC5905661 DOI: 10.1093/biolre/ioy016] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2017] [Revised: 12/01/2017] [Accepted: 01/19/2018] [Indexed: 11/15/2022] Open
Abstract
The Ca2+ entry mechanism that sustains the Ca2+ oscillations in fertilized pig oocytes was investigated. Stromal interaction molecule 1 (STIM1) and ORAI1 proteins tagged with various fluorophores were expressed in the oocytes. In some cells, the Ca2+ stores were depleted using cyclopiazonic acid (CPA); others were inseminated. Changes in the oocytes' cytosolic free Ca2+ concentration were monitored, while interaction between the expressed fusion proteins was investigated using fluorescence resonance energy transfer (FRET). Store depletion led to an increase of the FRET signal in oocytes co-expressing mVenus-STIM1 and mTurquoise2-ORAI1, indicating that Ca2+ release was followed by an interaction between these proteins. A similar FRET increase in response to CPA was also detected in oocytes co-expressing mVenus-STIM1 and mTurquoise2-STIM1, which is consistent with STIM1 forming punctae after store depletion. ML-9, an inhibitor that can interfere with STIM1 puncta formation, blocked store-operated Ca2+ entry (SOCE) induced by Ca2+ add-back after a CPA treatment; it also disrupted the Ca2+ oscillations in fertilized oocytes. In addition, oocytes overexpressing mVenus-STIM1 showed high-frequency Ca2+ oscillations when fertilized, arguing for an active role of the protein. High-frequency Ca2+ oscillations were also detected in fertilized oocytes co-expressing mVenus-STIM1 and mTurquoise2-ORAI1, and both of these high-frequency Ca2+ oscillations could be stopped by inhibitors of SOCE. Importantly, in oocytes co-expressing mVenus-STIM1 and mTurquoise2-ORAI1, we were also able to detect cyclic increases of the FRET signal indicating repetitive interactions between STIM1 and ORAI1. The results confirm the notion that in pig oocytes, SOCE is involved in the maintenance of the repetitive Ca2+ transients at fertilization.
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Affiliation(s)
- Lu Zhang
- Department of Animal Sciences, Purdue University, West Lafayette, Indiana, USA
| | | | - Laurie A Jaeger
- Department of Basic Medical Sciences, Purdue University, West Lafayette, Indiana, USA
| | - Agnes Bali Papp
- Department of Animal Sciences, Széchenyi István University, Győr, Hungary
| | - Zoltan Machaty
- Department of Animal Sciences, Purdue University, West Lafayette, Indiana, USA
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48
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Palty R, Fu Z, Isacoff EY. Sequential Steps of CRAC Channel Activation. Cell Rep 2018; 19:1929-1939. [PMID: 28564609 DOI: 10.1016/j.celrep.2017.05.025] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2016] [Revised: 03/27/2017] [Accepted: 05/05/2017] [Indexed: 10/19/2022] Open
Abstract
Interaction between the endoplasmic reticulum protein STIM1 and the plasma membrane channel ORAI1 generates calcium signals that are central for diverse cellular functions. How STIM1 binds and activates ORAI1 remains poorly understood. Using electrophysiological, optical, and biochemical techniques, we examined the effects of mutations in the STIM1-ORAI1 activating region (SOAR) of STIM1. We find that SOAR mutants that are deficient in binding to resting ORAI1 channels are able to bind to and boost activation of partially activated ORAI1 channels. We further show that the STIM1 binding regions on ORAI1 undergo structural rearrangement during channel activation. The results suggest that activation of ORAI1 by SOAR occurs in multiple steps. In the first step, SOAR binds to ORAI1, partially activates the channel, and induces a rearrangement in the SOAR-binding site of ORAI1. That rearrangement of ORAI1 then permits sequential steps of SOAR binding, via distinct molecular interactions, to fully activate the channel.
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Affiliation(s)
- Raz Palty
- Department of Biochemistry, Ruth and Bruce Rappaport Faculty of Medicine, Technion - Israel Institute of Technology, Haifa 31096, Israel.
| | - Zhu Fu
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Ehud Y Isacoff
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720, USA; Helen Wills Neuroscience Institute, University of California, Berkeley, Berkeley, CA 94720, USA; Bioscience Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA.
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49
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Abstract
Fast Ca2+-dependent inactivation (FCDI) is a safety mechanism limiting Ca2+ entry through some types of Ca2+ channels, including Ca2+ release-activated Ca2+ (CRAC) channels. This type of inactivation is caused by Ca2+, which passes through Ca2+ channel and binds to a specific site within a short distance from the inner mouth of the pore, causing channel to shut.The main technique that is used to investigate FCDI is whole-cell patch clamping. Since the cloning of the molecular components of the CRAC channel, STIM1 and Orai1, FCDI of CRAC channel has been studied using HEK293T heterologous expression system. In this paper we describe a method of quantifying CRAC channel FCDI by using instantaneous tail currents.
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Affiliation(s)
- Grigori Y Rychkov
- School of Medicine, University of Adelaide, South Australian Health and Medical Research Institute (SAHMRI), Adelaide, SA, Australia.
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50
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Fine-tuning of store-operated calcium entry by fast and slow Ca 2+-dependent inactivation: Involvement of SARAF. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2017; 1865:463-469. [PMID: 29223474 DOI: 10.1016/j.bbamcr.2017.12.001] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/21/2017] [Revised: 12/02/2017] [Accepted: 12/04/2017] [Indexed: 02/07/2023]
Abstract
Store-operated Ca2+ entry (SOCE) is a functionally relevant mechanism for Ca2+ influx present in electrically excitable and non-excitable cells. Regulation of Ca2+ entry through store-operated channels is essential to maintain an appropriate intracellular Ca2+ homeostasis and prevent cell damage. Calcium-release activated channels exhibit Ca2+-dependent inactivation mediated by two temporally separated mechanisms: fast Ca2+-dependent inactivation takes effect in the order of milliseconds and involves the interaction of Ca2+ with residues in the channel pore while slow Ca2+-dependent inactivation (SCDI) develops over tens of seconds, requires a global rise in [Ca2+]cyt and is a mechanism regulated by mitochondria. Recent studies have provided evidence that the protein SARAF (SOCE-associated regulatory factor) is involved in the mechanism underlying SCDI of Orai1. SARAF is an endoplasmic reticulum (ER) membrane protein that associates with STIM1 and translocate to plasma membrane-ER junctions in a STIM1-dependent manner upon store depletion to modulate SOCE. SCDI mediated by SARAF depends on the location of the STIM1-Orai1 complex within a PI(4,5)P2-rich microdomain. SARAF also interacts with Orai1 and TRPC1 in cells endogenously expressing STIM1 and cells with a low STIM1 expression and modulates channel function. This review focuses on the modulation by SARAF of SOCE and other forms of Ca2+ influx mediated by Orai1 and TRPC1 in order to provide spatio-temporally regulated Ca2+ signals.
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