1
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Sallinger M, Grabmayr H, Humer C, Bonhenry D, Romanin C, Schindl R, Derler I. Activation mechanisms and structural dynamics of STIM proteins. J Physiol 2024; 602:1475-1507. [PMID: 36651592 DOI: 10.1113/jp283828] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2022] [Accepted: 01/11/2023] [Indexed: 01/19/2023] Open
Abstract
The family of stromal interaction molecules (STIM) includes two widely expressed single-pass endoplasmic reticulum (ER) transmembrane proteins and additional splice variants that act as precise ER-luminal Ca2+ sensors. STIM proteins mainly function as one of the two essential components of the so-called Ca2+ release-activated Ca2+ (CRAC) channel. The second CRAC channel component is constituted by pore-forming Orai proteins in the plasma membrane. STIM and Orai physically interact with each other to enable CRAC channel opening, which is a critical prerequisite for various downstream signalling pathways such as gene transcription or proliferation. Their activation commonly requires the emptying of the intracellular ER Ca2+ store. Using their Ca2+ sensing capabilities, STIM proteins confer this Ca2+ content-dependent signal to Orai, thereby linking Ca2+ store depletion to CRAC channel opening. Here we review the conformational dynamics occurring along the entire STIM protein upon store depletion, involving the transition from the quiescent, compactly folded structure into an active, extended state, modulation by a variety of accessory components in the cell as well as the impairment of individual steps of the STIM activation cascade associated with disease.
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Affiliation(s)
- Matthias Sallinger
- Institute of Biophysics, JKU Life Science Center, Johannes Kepler University Linz, Linz, Austria
| | - Herwig Grabmayr
- Institute of Biophysics, JKU Life Science Center, Johannes Kepler University Linz, Linz, Austria
| | - Christina Humer
- Institute of Biophysics, JKU Life Science Center, Johannes Kepler University Linz, Linz, Austria
| | - Daniel Bonhenry
- Center for Nanobiology and Structural Biology, Institute of Microbiology, Academy of Sciences of the Czech Republic, Nove Hrady, Czech Republic
| | - Christoph Romanin
- Institute of Biophysics, JKU Life Science Center, Johannes Kepler University Linz, Linz, Austria
| | - Rainer Schindl
- Gottfried Schatz Research Centre, Medical University of Graz, Graz, Austria
- BioTechMed-Graz, Graz, Austria
| | - Isabella Derler
- Institute of Biophysics, JKU Life Science Center, Johannes Kepler University Linz, Linz, Austria
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2
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Liu X, Zheng T, Jiang Y, Wang L, Zhang Y, Liang Q, Chen Y. Molecular Mechanism Analysis of STIM1 Thermal Sensation. Cells 2023; 12:2613. [PMID: 37998348 PMCID: PMC10670385 DOI: 10.3390/cells12222613] [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: 10/02/2023] [Revised: 11/05/2023] [Accepted: 11/10/2023] [Indexed: 11/25/2023] Open
Abstract
STIM1 has been identified as a new warm sensor, but the exact molecular mechanism remains unclear. In this study, a variety of mutants of STIM1, Orai1 and Orai3 were generated. The single-cell calcium imaging and confocal analysis were used to evaluate the thermal sensitivity of the resulting STIM mutants and the interaction between STIM1 and Orai mutants in response to temperature. Our results suggested that the CC1-SOAR of STIM1 was a direct activation domain of temperature, leading to subsequent STIM1 activation, and the transmembrane (TM) region and K domain but not EF-SAM were needed for this process. Furthermore, both the TM and SOAR domains exhibited similarities and differences between STIM1-mediated thermal sensation and store-operated calcium entry (SOCE), and the key sites of Orai1 showed similar roles in these two responses. Additionally, the TM23 (comprising TM2, loop2, and TM3) region of Orai1 was identified as the key domain determining the STIM1/Orai1 thermal response pattern, while the temperature reactive mode of STIM1/Orai3 seemed to result from a combined effect of Orai3. These findings provide important support for the specific molecular mechanism of STIM1-induced thermal response, as well as the interaction mechanism of STIM1 with Orai1 and Orai3 after being activated by temperature.
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Affiliation(s)
- Xiaoling Liu
- School of Life Sciences, Beijing University of Chinese Medicine, Beijing 102401, China; (T.Z.); (L.W.); (Y.Z.); (Q.L.)
| | - Tianyuan Zheng
- School of Life Sciences, Beijing University of Chinese Medicine, Beijing 102401, China; (T.Z.); (L.W.); (Y.Z.); (Q.L.)
| | - Yan Jiang
- School of Pharmaceutical Sciences, Tsinghua University, Beijing 100084, China;
| | - Lei Wang
- School of Life Sciences, Beijing University of Chinese Medicine, Beijing 102401, China; (T.Z.); (L.W.); (Y.Z.); (Q.L.)
| | - Yuchen Zhang
- School of Life Sciences, Beijing University of Chinese Medicine, Beijing 102401, China; (T.Z.); (L.W.); (Y.Z.); (Q.L.)
| | - Qiyu Liang
- School of Life Sciences, Beijing University of Chinese Medicine, Beijing 102401, China; (T.Z.); (L.W.); (Y.Z.); (Q.L.)
| | - Yuejie Chen
- School of Pharmacy, Minzu University of China, Beijing 100081, China
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3
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Kouba S, Buscaglia P, Guéguinou M, Ibrahim S, Félix R, Guibon R, Fromont G, Pigat N, Capiod T, Vandier C, Mignen O, Potier-Cartereau M. Pivotal role of the ORAI3-STIM2 complex in the control of mitotic death and prostate cancer cell cycle progression. Cell Calcium 2023; 115:102794. [PMID: 37597301 DOI: 10.1016/j.ceca.2023.102794] [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: 05/22/2023] [Revised: 07/27/2023] [Accepted: 08/12/2023] [Indexed: 08/21/2023]
Abstract
Prostate cancer (PCa) represents one of the most frequent diagnosed cancer in males worldwide. Due to routine screening tests and the efficiency of available treatments, PCa-related deaths have significantly decreased over the past decades. However, PCa remains a critical threat if detected at a late stage in which, cancer cells would have already detached from the primary tumor to spread and invade other parts of the body. Calcium (Ca2+) channels and their protein regulators are now considered as hallmarks of cancer and some of them have been well examined in PCa. Among these Ca2+ channels, isoform 3 of the ORAI channel family has been shown to regulate the proliferation of PCa cells via the Arachidonic Acid-mediated Ca2+ entry, requiring the involvement of STIM1 (Stromal Interaction Molecule 1). Still, no study has yet demonstrated a role of the "neglected" STIM2 isoform in PCa or if it may interact with ORAI3 to promote an oncogenic behavior. In this study, we demonstrate that ORAI3 and STIM2 are upregulated in human PCa tissues. In old KIMAP (Knock-In Mouse Prostate Adenocarcinoma) mice, ORAI3 and STIM2 mRNA levels were significantly higher than ORAI1 and STIM1. In vitro, we show that ORAI3-STIM2 interact under basal conditions in PC-3 cells. ORAI3 silencing increased Store Operated Ca2+ Entry (SOCE) and induced a significant increase of the cell population in G2/M phase of the cell cycle, consistent with the role of ORAI3 as a negative regulator of SOCE. Higher expression levels of CDK1-Y15/Cyclin B1 were detected and mitotic arrest-related death occurred after ORAI3 silencing, which resulted in activating Bax/Bcl-2-mediated apoptotic pathway and caspase-8 activation and cleavage. STIM2 and ORAI3 expression increased in M phase while STIM1 expression and SOCE amplitude significantly decreased. Taken together, ORAI3 -STIM2 complex allows a successful progression through mitosis of PCa cells by evading mitotic catastrophe.
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Affiliation(s)
- Sana Kouba
- INSERM U1069, N2C: Nutrition, Croissance et Cancer, University of Tours, Tours, France
| | - Paul Buscaglia
- INSERM U1227, LBAI: Lymphocytes B, Autoimmunité et Immunotherapies, University of Bretagne Occidentale, Brest, France
| | - Maxime Guéguinou
- INSERM U1069, N2C: Nutrition, Croissance et Cancer, University of Tours, Tours, France
| | - Sajida Ibrahim
- EA 7501, University of Tours - ERL 7001 LNOx - CNRS, GICC: Groupe Innovation et Ciblage Cellulaire, Tours, France
| | - Romain Félix
- INSERM U1227, LBAI: Lymphocytes B, Autoimmunité et Immunotherapies, University of Bretagne Occidentale, Brest, France
| | - Roseline Guibon
- INSERM U1069, N2C: Nutrition, Croissance et Cancer, University of Tours, Tours, France; Service d'Anatomie et cytologie pathologiques, Bretonneau, Centre Hospitalier Régional et Universitaire, Tours, France
| | - Gaëlle Fromont
- INSERM U1069, N2C: Nutrition, Croissance et Cancer, University of Tours, Tours, France; Service d'Anatomie et cytologie pathologiques, Bretonneau, Centre Hospitalier Régional et Universitaire, Tours, France
| | - Natascha Pigat
- INSERM U1151, Institut Necker Enfants Malades, Universiy of Paris, 160 rue de Vaugirard, Paris 75015 France
| | - Thierry Capiod
- INSERM U1151, Institut Necker Enfants Malades, Universiy of Paris, 160 rue de Vaugirard, Paris 75015 France
| | - Christophe Vandier
- INSERM U1069, N2C: Nutrition, Croissance et Cancer, University of Tours, Tours, France
| | - Olivier Mignen
- INSERM U1227, LBAI: Lymphocytes B, Autoimmunité et Immunotherapies, University of Bretagne Occidentale, Brest, France.
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4
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Neamtu A, Serban DN, Barritt GJ, Isac DL, Vasiliu T, Laaksonen A, Serban IL. Molecular dynamics simulations reveal the hidden EF-hand of EF-SAM as a possible key thermal sensor for STIM1 activation by temperature. J Biol Chem 2023; 299:104970. [PMID: 37380078 PMCID: PMC10400917 DOI: 10.1016/j.jbc.2023.104970] [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: 02/10/2023] [Revised: 06/07/2023] [Accepted: 06/22/2023] [Indexed: 06/30/2023] Open
Abstract
Intracellular calcium signaling is essential for many cellular processes, including store-operated Ca2+ entry (SOCE), which is initiated by stromal interaction molecule 1 (STIM1) detecting endoplasmic reticulum (ER) Ca2+ depletion. STIM1 is also activated by temperature independent of ER Ca2+ depletion. Here we provide evidence, from advanced molecular dynamics simulations, that EF-SAM may act as a true temperature sensor for STIM1, with the prompt and extended unfolding of the hidden EF-hand subdomain (hEF) even at slightly elevated temperatures, exposing a highly conserved hydrophobic Phe108. Our study also suggests an interplay between Ca2+ and temperature sensing, as both, the canonical EF-hand subdomain (cEF) and the hidden EF-hand subdomain (hEF), exhibit much higher thermal stability in the Ca2+-loaded form compared to the Ca2+-free form. The SAM domain, surprisingly, displays high thermal stability compared to the EF-hands and may act as a stabilizer for the latter. We propose a modular architecture for the EF-hand-SAM domain of STIM1 composed of a thermal sensor (hEF), a Ca2+ sensor (cEF), and a stabilizing domain (SAM). Our findings provide important insights into the mechanism of temperature-dependent regulation of STIM1, which has broad implications for understanding the role of temperature in cellular physiology.
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Affiliation(s)
- Andrei Neamtu
- Department of Physiology, "Grigore T. Popa" University of Medicine and Pharmacy, Iasi, Romania; Center of Advanced Research in Bionanocojugates and Biopolymers, "Petru Poni" Institute of Macromolecular Chemistry Iasi, Iasi, Romania
| | - Dragomir N Serban
- Department of Physiology, "Grigore T. Popa" University of Medicine and Pharmacy, Iasi, Romania.
| | - Greg J Barritt
- Discipline of Medical Biochemistry, College of Medicine and Public Health, Flinders University, Adelaide, SA, Australia
| | - Dragos Lucian Isac
- Center of Advanced Research in Bionanocojugates and Biopolymers, "Petru Poni" Institute of Macromolecular Chemistry Iasi, Iasi, Romania
| | - Tudor Vasiliu
- Center of Advanced Research in Bionanocojugates and Biopolymers, "Petru Poni" Institute of Macromolecular Chemistry Iasi, Iasi, Romania
| | - Aatto Laaksonen
- Department of Materials and Environmental Chemistry, Arrhenius Laboratory, Stockholm University, Stockholm, Sweden; Centre of Advanced Research in Bionanoconjugates and Biopolymers, Petru Poni Institute of Macromolecular Chemistry, Iasi, Romania; State Key Laboratory of Materials-Oriented and Chemical Engineering, Nanjing Tech University, Nanjing, P. R. China
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5
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Cohen HA, Zomot E, Nataniel T, Militsin R, Palty R. The SOAR of STIM1 interacts with plasma membrane lipids to form ER-PM contact sites. Cell Rep 2023; 42:112238. [PMID: 36906853 DOI: 10.1016/j.celrep.2023.112238] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2022] [Revised: 01/15/2023] [Accepted: 02/23/2023] [Indexed: 03/12/2023] Open
Abstract
Depletion of Ca2+ from the endoplasmic reticulum (ER) causes the ER Ca2+ sensor STIM1 to form membrane contact sites (MCSs) with the plasma membrane (PM). At the ER-PM MCS, STIM1 binds to Orai channels to induce cellular Ca2+ entry. The prevailing view of this sequential process is that STIM1 interacts with the PM and with Orai1 using two separate modules: a C-terminal polybasic domain (PBD) for the interaction with PM phosphoinositides and the STIM-Orai activation region (SOAR) for the interaction with Orai channels. Here, using electron and fluorescence microscopy and protein-lipid interaction assays, we show that oligomerization of the SOAR promotes direct interaction with PM phosphoinositides to trap STIM1 at ER-PM MCSs. The interaction depends on a cluster of conserved lysine residues within the SOAR and is co-regulated by the STIM1 coil-coiled 1 and inactivation domains. Collectively, our findings uncover a molecular mechanism for formation and regulation of ER-PM MCSs by STIM1.
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Affiliation(s)
- Hadas Achildiev Cohen
- Department of Biochemistry, Technion Integrated Cancer Center, Ruth and Bruce Rappaport Faculty of Medicine, Technion - Israel Institute of Technology, Haifa 31096, Israel
| | - Elia Zomot
- Department of Biochemistry, Technion Integrated Cancer Center, Ruth and Bruce Rappaport Faculty of Medicine, Technion - Israel Institute of Technology, Haifa 31096, Israel
| | - Tomer Nataniel
- Department of Biochemistry, Technion Integrated Cancer Center, Ruth and Bruce Rappaport Faculty of Medicine, Technion - Israel Institute of Technology, Haifa 31096, Israel
| | - Ruslana Militsin
- Department of Biochemistry, Technion Integrated Cancer Center, Ruth and Bruce Rappaport Faculty of Medicine, Technion - Israel Institute of Technology, Haifa 31096, Israel
| | - Raz Palty
- Department of Biochemistry, Technion Integrated Cancer Center, Ruth and Bruce Rappaport Faculty of Medicine, Technion - Israel Institute of Technology, Haifa 31096, Israel.
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6
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STIM Proteins and Regulation of SOCE in ER-PM Junctions. Biomolecules 2022; 12:biom12081152. [PMID: 36009047 PMCID: PMC9405863 DOI: 10.3390/biom12081152] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2022] [Revised: 08/12/2022] [Accepted: 08/15/2022] [Indexed: 11/30/2022] Open
Abstract
ER-PM junctions are membrane contact sites formed by the endoplasmic reticulum (ER) and plasma membrane (PM) in close apposition together. The formation and stability of these junctions are dependent on constitutive and dynamic enrichment of proteins, which either contribute to junctional stability or modulate the lipid levels of both ER and plasma membranes. The ER-PM junctions have come under much scrutiny recently as they serve as hubs for assembling the Ca2+ signaling complexes. This review summarizes: (1) key findings that underlie the abilities of STIM proteins to accumulate in ER-PM junctions; (2) the modulation of Orai/STIM complexes by other components found within the same junction; and (3) how Orai1 channel activation is coordinated and coupled with downstream signaling pathways.
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7
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Tombaz M, Yanyatan C, Keskus AG, Konu O. Extraction and Prioritization of a Gene-Cancer-By-Survival Network Involved in Homeostasis of Intracellular Calcium Concentrations Using TCGA PANCAN Data. Bioelectricity 2022. [DOI: 10.1089/bioe.2022.0013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Affiliation(s)
- Melike Tombaz
- Department of Molecular Biology and Genetics, Bilkent University, Ankara, Turkey
| | - Cagdas Yanyatan
- Department of Molecular Biology and Genetics, Bilkent University, Ankara, Turkey
| | | | - Ozlen Konu
- Department of Molecular Biology and Genetics, Bilkent University, Ankara, Turkey
- Neuroscience Program, Bilkent University, Ankara, Turkey
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8
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Collins HE, Zhang D, Chatham JC. STIM and Orai Mediated Regulation of Calcium Signaling in Age-Related Diseases. FRONTIERS IN AGING 2022; 3:876785. [PMID: 35821821 PMCID: PMC9261457 DOI: 10.3389/fragi.2022.876785] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/15/2022] [Accepted: 03/30/2022] [Indexed: 01/19/2023]
Abstract
Tight spatiotemporal regulation of intracellular Ca2+ plays a critical role in regulating diverse cellular functions including cell survival, metabolism, and transcription. As a result, eukaryotic cells have developed a wide variety of mechanisms for controlling Ca2+ influx and efflux across the plasma membrane as well as Ca2+ release and uptake from intracellular stores. The STIM and Orai protein families comprising of STIM1, STIM2, Orai1, Orai2, and Orai3, are evolutionarily highly conserved proteins that are core components of all mammalian Ca2+ signaling systems. STIM1 and Orai1 are considered key players in the regulation of Store Operated Calcium Entry (SOCE), where release of Ca2+ from intracellular stores such as the Endoplasmic/Sarcoplasmic reticulum (ER/SR) triggers Ca2+ influx across the plasma membrane. SOCE, which has been widely characterized in non-excitable cells, plays a central role in Ca2+-dependent transcriptional regulation. In addition to their role in Ca2+ signaling, STIM1 and Orai1 have been shown to contribute to the regulation of metabolism and mitochondrial function. STIM and Orai proteins are also subject to redox modifications, which influence their activities. Considering their ubiquitous expression, there has been increasing interest in the roles of STIM and Orai proteins in excitable cells such as neurons and myocytes. While controversy remains as to the importance of SOCE in excitable cells, STIM1 and Orai1 are essential for cellular homeostasis and their disruption is linked to various diseases associated with aging such as cardiovascular disease and neurodegeneration. The recent identification of splice variants for most STIM and Orai isoforms while complicating our understanding of their function, may also provide insight into some of the current contradictions on their roles. Therefore, the goal of this review is to describe our current understanding of the molecular regulation of STIM and Orai proteins and their roles in normal physiology and diseases of aging, with a particular focus on heart disease and neurodegeneration.
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Affiliation(s)
- Helen E. Collins
- Division of Environmental Medicine, Department of Medicine, University of Louisville, Louisville, KY, United States
| | - Dingguo Zhang
- Division of Molecular and Cellular Pathology, Department of PathologyUniversity of Alabama at Birmingham, Birmingham, AL, United States
| | - John C. Chatham
- Division of Molecular and Cellular Pathology, Department of PathologyUniversity of Alabama at Birmingham, Birmingham, AL, United States,*Correspondence: John C. Chatham,
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9
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Maltan L, Andova AM, Derler I. The Role of Lipids in CRAC Channel Function. Biomolecules 2022; 12:biom12030352. [PMID: 35327543 PMCID: PMC8944985 DOI: 10.3390/biom12030352] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2022] [Revised: 02/12/2022] [Accepted: 02/20/2022] [Indexed: 11/28/2022] Open
Abstract
The composition and dynamics of the lipid membrane define the physical properties of the bilayer and consequently affect the function of the incorporated membrane transporters, which also applies for the prominent Ca2+ release-activated Ca2+ ion channel (CRAC). This channel is activated by receptor-induced Ca2+ store depletion of the endoplasmic reticulum (ER) and consists of two transmembrane proteins, STIM1 and Orai1. STIM1 is anchored in the ER membrane and senses changes in the ER luminal Ca2+ concentration. Orai1 is the Ca2+-selective, pore-forming CRAC channel component located in the plasma membrane (PM). Ca2+ store-depletion of the ER triggers activation of STIM1 proteins, which subsequently leads to a conformational change and oligomerization of STIM1 and its coupling to as well as activation of Orai1 channels at the ER-PM contact sites. Although STIM1 and Orai1 are sufficient for CRAC channel activation, their efficient activation and deactivation is fine-tuned by a variety of lipids and lipid- and/or ER-PM junction-dependent accessory proteins. The underlying mechanisms for lipid-mediated CRAC channel modulation as well as the still open questions, are presented in this review.
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10
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Johnson J, Blackman R, Gross S, Soboloff J. Control of STIM and Orai function by post-translational modifications. Cell Calcium 2022; 103:102544. [PMID: 35151050 PMCID: PMC8960353 DOI: 10.1016/j.ceca.2022.102544] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2021] [Revised: 01/17/2022] [Accepted: 01/26/2022] [Indexed: 12/15/2022]
Abstract
Store-operated calcium entry (SOCE) is mediated by the endoplasmic reticulum (ER) Ca2+ sensors stromal interaction molecules (STIM1 and STIM2) and the plasma membrane Orai (Orai1, Orai2, Orai3) Ca2+ channels. Although primarily regulated by ER Ca2+ content, there have been numerous studies over the last 15 years demonstrating that all 5 proteins are also regulated through post-translational modification (PTM). Focusing primarily on phosphorylation, glycosylation and redox modification, this review focuses on how PTMs modulate the key events in SOCE; Ca2+ sensing, STIM translocation, Orai interaction and/or Orai1 activation.
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11
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Lilliu E, Koenig S, Koenig X, Frieden M. Store-Operated Calcium Entry in Skeletal Muscle: What Makes It Different? Cells 2021; 10:cells10092356. [PMID: 34572005 PMCID: PMC8468011 DOI: 10.3390/cells10092356] [Citation(s) in RCA: 2] [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: 08/05/2021] [Revised: 09/03/2021] [Accepted: 09/04/2021] [Indexed: 01/26/2023] Open
Abstract
Current knowledge on store-operated Ca2+ entry (SOCE) regarding its localization, kinetics, and regulation is mostly derived from studies performed in non-excitable cells. After a long time of relative disinterest in skeletal muscle SOCE, this mechanism is now recognized as an essential contributor to muscle physiology, as highlighted by the muscle pathologies that are associated with mutations in the SOCE molecules STIM1 and Orai1. This review mainly focuses on the peculiar aspects of skeletal muscle SOCE that differentiate it from its counterpart found in non-excitable cells. This includes questions about SOCE localization and the movement of respective proteins in the highly organized skeletal muscle fibers, as well as the diversity of expressed STIM isoforms and their differential expression between muscle fiber types. The emerging evidence of a phasic SOCE, which is activated during EC coupling, and its physiological implication is described as well. The specific issues related to the use of SOCE modulators in skeletal muscles are discussed. This review highlights the complexity of SOCE activation and its regulation in skeletal muscle, with an emphasis on the most recent findings and the aim to reach a current picture of this mesmerizing phenomenon.
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Affiliation(s)
- Elena Lilliu
- Center for Physiology and Pharmacology, Department of Neurophysiology and Pharmacology, Medical University of Vienna, 1090 Vienna, Austria;
| | - Stéphane Koenig
- Department of Cell Physiology and Metabolism, University of Geneva, 1201 Geneva, Switzerland;
| | - Xaver Koenig
- Center for Physiology and Pharmacology, Department of Neurophysiology and Pharmacology, Medical University of Vienna, 1090 Vienna, Austria;
- Correspondence: (X.K.); (M.F.)
| | - Maud Frieden
- Department of Cell Physiology and Metabolism, University of Geneva, 1201 Geneva, Switzerland;
- Correspondence: (X.K.); (M.F.)
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12
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Regulation of Store-Operated Ca 2+ Entry by SARAF. Cells 2021; 10:cells10081887. [PMID: 34440656 PMCID: PMC8391525 DOI: 10.3390/cells10081887] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Revised: 07/19/2021] [Accepted: 07/22/2021] [Indexed: 12/14/2022] Open
Abstract
Calcium (Ca2+) signaling plays a dichotomous role in cellular biology, controlling cell survival and proliferation on the one hand and cellular toxicity and cell death on the other. Store-operated Ca2+ entry (SOCE) by CRAC channels represents a major pathway for Ca2+ entry in non-excitable cells. The CRAC channel has two key components, the endoplasmic reticulum Ca2+ sensor stromal interaction molecule (STIM) and the plasma-membrane Ca2+ channel Orai. Physical coupling between STIM and Orai opens the CRAC channel and the resulting Ca2+ flux is regulated by a negative feedback mechanism of slow Ca2+ dependent inactivation (SCDI). The identification of the SOCE-associated regulatory factor (SARAF) and investigations of its role in SCDI have led to new functional and molecular insights into how SOCE is controlled. In this review, we provide an overview of the functional and molecular mechanisms underlying SCDI and discuss how the interaction between SARAF, STIM1, and Orai1 shapes Ca2+ signaling in cells.
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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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14
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Crul T, Maléth J. Endoplasmic Reticulum-Plasma Membrane Contact Sites as an Organizing Principle for Compartmentalized Calcium and cAMP Signaling. Int J Mol Sci 2021; 22:ijms22094703. [PMID: 33946838 PMCID: PMC8124356 DOI: 10.3390/ijms22094703] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2021] [Revised: 04/20/2021] [Accepted: 04/27/2021] [Indexed: 01/14/2023] Open
Abstract
In eukaryotic cells, ultimate specificity in activation and action-for example, by means of second messengers-of the myriad of signaling cascades is primordial. In fact, versatile and ubiquitous second messengers, such as calcium (Ca2+) and cyclic adenosine monophosphate (cAMP), regulate multiple-sometimes opposite-cellular functions in a specific spatiotemporal manner. Cells achieve this through segregation of the initiators and modulators to specific plasma membrane (PM) subdomains, such as lipid rafts and caveolae, as well as by dynamic close contacts between the endoplasmic reticulum (ER) membrane and other intracellular organelles, including the PM. Especially, these membrane contact sites (MCSs) are currently receiving a lot of attention as their large influence on cell signaling regulation and cell physiology is increasingly appreciated. Depletion of ER Ca2+ stores activates ER membrane STIM proteins, which activate PM-residing Orai and TRPC Ca2+ channels at ER-PM contact sites. Within the MCS, Ca2+ fluxes relay to cAMP signaling through highly interconnected networks. However, the precise mechanisms of MCS formation and the influence of their dynamic lipid environment on their functional maintenance are not completely understood. The current review aims to provide an overview of our current understanding and to identify open questions of the field.
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Affiliation(s)
- Tim Crul
- First Department of Medicine, University of Szeged, H6720 Szeged, Hungary
- HAS-USZ Momentum Epithelial Cell Signaling and Secretion Research Group, University of Szeged, H6720 Szeged, Hungary
- HCEMM-SZTE Molecular Gastroenterology Research Group, University of Szeged, H6720 Szeged, Hungary
- Correspondence: (T.C.); (J.M.)
| | - József Maléth
- First Department of Medicine, University of Szeged, H6720 Szeged, Hungary
- HAS-USZ Momentum Epithelial Cell Signaling and Secretion Research Group, University of Szeged, H6720 Szeged, Hungary
- HCEMM-SZTE Molecular Gastroenterology Research Group, University of Szeged, H6720 Szeged, Hungary
- Correspondence: (T.C.); (J.M.)
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15
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Wang WA, Demaurex N. Proteins Interacting with STIM1 and Store-Operated Ca 2+ Entry. PROGRESS IN MOLECULAR AND SUBCELLULAR BIOLOGY 2021; 59:51-97. [PMID: 34050862 DOI: 10.1007/978-3-030-67696-4_4] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
The endoplasmic reticulum (ER) Ca2+ sensor stromal interaction molecule 1 (STIM1) interacts with ORAI Ca2+ channels at the plasma membrane to regulate immune and muscle cell function. The conformational changes underlying STIM1 activation, translocation, and ORAI1 trapping and gating, are stringently regulated by post-translational modifications and accessory proteins. Here, we review the recent progress in the identification and characterization of ER and cytosolic proteins interacting with STIM1 to control its activation and deactivation during store-operated Ca2+ entry (SOCE).
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Affiliation(s)
- Wen-An Wang
- Department of Cellular Physiology and Metabolism, University of Geneva, Geneva, Switzerland
| | - Nicolas Demaurex
- Department of Cellular Physiology and Metabolism, University of Geneva, Geneva, Switzerland.
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16
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STIM2 targets Orai1/STIM1 to the AKAP79 signaling complex and confers coupling of Ca 2+ entry with NFAT1 activation. Proc Natl Acad Sci U S A 2020; 117:16638-16648. [PMID: 32601188 DOI: 10.1073/pnas.1915386117] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The Orai1 channel is regulated by stromal interaction molecules STIM1 and STIM2 within endoplasmic reticulum (ER)-plasma membrane (PM) contact sites. Ca2+ signals generated by Orai1 activate Ca2+-dependent gene expression. When compared with STIM1, STIM2 is a weak activator of Orai1, but it has been suggested to have a unique role in nuclear factor of activated T cells 1 (NFAT1) activation triggered by Orai1-mediated Ca2+ entry. In this study, we examined the contribution of STIM2 in NFAT1 activation. We report that STIM2 recruitment of Orai1/STIM1 to ER-PM junctions in response to depletion of ER-Ca2+ promotes assembly of the channel with AKAP79 to form a signaling complex that couples Orai1 channel function to the activation of NFAT1. Knockdown of STIM2 expression had relatively little effect on Orai1/STIM1 clustering or local and global [Ca2+]i increases but significantly attenuated NFAT1 activation and assembly of Orai1 with AKAP79. STIM1ΔK, which lacks the PIP2-binding polybasic domain, was recruited to ER-PM junctions following ER-Ca2+ depletion by binding to Orai1 and caused local and global [Ca2+]i increases comparable to those induced by STIM1 activation of Orai1. However, in contrast to STIM1, STIM1ΔK induced less NFAT1 activation and attenuated the association of Orai1 with STIM2 and AKAP79. Orai1-AKAP79 interaction and NFAT1 activation were recovered by coexpressing STIM2 with STIM1ΔK. Replacing the PIP2-binding domain of STIM1 with that of STIM2 eliminated the requirement of STIM2 for NFAT1 activation. Together, these data demonstrate an important role for STIM2 in coupling Orai1-mediated Ca2+ influx to NFAT1 activation.
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17
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Novello MJ, Zhu J, Zhang M, Feng Q, Stathopulos PB. Synergistic stabilization by nitrosoglutathione-induced thiol modifications in the stromal interaction molecule-2 luminal domain suppresses basal and store operated calcium entry. Sci Rep 2020; 10:10177. [PMID: 32576932 PMCID: PMC7311479 DOI: 10.1038/s41598-020-66961-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2019] [Accepted: 06/01/2020] [Indexed: 11/25/2022] Open
Abstract
Stromal interaction molecule−1 and −2 (STIM1/2) are endoplasmic reticulum (ER) membrane-inserted calcium (Ca2+) sensing proteins that, together with Orai1-composed Ca2+ channels on the plasma membrane (PM), regulate intracellular Ca2+ levels. Recent evidence suggests that S-nitrosylation of the luminal STIM1 Cys residues inhibits store operated Ca2+ entry (SOCE). However, the effects of thiol modifications on STIM2 during nitrosative stress and their role in regulating basal Ca2+ levels remain unknown. Here, we demonstrate that the nitric oxide (NO) donor nitrosoglutathione (GSNO) thermodynamically stabilizes the STIM2 Ca2+ sensing region in a Cys-specific manner. We uncovered a remarkable synergism in this stabilization involving the three luminal Cys of STIM2, which is unique to this paralog. S-Nitrosylation causes structural perturbations that converge on the face of the EF-hand and sterile α motif (EF-SAM) domain, implicated in unfolding-coupled activation. In HEK293T cells, enhanced free basal cytosolic Ca2+ and SOCE mediated by STIM2 overexpression could be attenuated by GSNO or mutation of the modifiable Cys located in the luminal domain. Collectively, we identify the Cys residues within the N-terminal region of STIM2 as modifiable targets during nitrosative stress that can profoundly and cooperatively affect basal Ca2+ and SOCE regulation.
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Affiliation(s)
- Matthew J Novello
- Department of Physiology and Pharmacology, Schulich School of Medicine and Dentistry, the University of Western Ontario, London, Ontario, N6A5C1, Canada
| | - Jinhui Zhu
- Department of Physiology and Pharmacology, Schulich School of Medicine and Dentistry, the University of Western Ontario, London, Ontario, N6A5C1, Canada.,Dentistry, Schulich School of Medicine and Dentistry, the University of Western Ontario, London, Ontario, N6A5C1, Canada
| | - MengQi Zhang
- Department of Physiology and Pharmacology, Schulich School of Medicine and Dentistry, the University of Western Ontario, London, Ontario, N6A5C1, Canada.,Faculty of Medicine, University of Ottawa, Ottawa, Ontario, K1H8M5, Canada
| | - Qingping Feng
- Department of Physiology and Pharmacology, Schulich School of Medicine and Dentistry, the University of Western Ontario, London, Ontario, N6A5C1, Canada.
| | - Peter B Stathopulos
- Department of Physiology and Pharmacology, Schulich School of Medicine and Dentistry, the University of Western Ontario, London, Ontario, N6A5C1, Canada.
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18
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Ong HL, Ambudkar IS. The Endoplasmic Reticulum-Plasma Membrane Junction: A Hub for Agonist Regulation of Ca 2+ Entry. Cold Spring Harb Perspect Biol 2020; 12:cshperspect.a035253. [PMID: 31501196 DOI: 10.1101/cshperspect.a035253] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Stimulation of cell-surface receptors induces cytosolic Ca2+ ([Ca2+]i) increases that are detected and transduced by effector proteins for regulation of cell function. Intracellular Ca2+ release, via endoplasmic reticulum (ER) proteins inositol 1,4,5-trisphosphate receptors (IP3R) and ryanodine receptors (RyR), and Ca2+ influx, via store-operated Ca2+ entry (SOCE), contribute to the increase in [Ca2+]i The amplitude, frequency, and spatial characteristics of the [Ca2+]i increases are controlled by the compartmentalization of proteins into signaling complexes such as receptor-signaling complexes and SOCE complexes. Both complexes include protein and lipid components, located in the plasma membrane (PM) and ER. Receptor signaling initiates in the PM via phospholipase C (PLC)-mediated hydrolysis of phosphatidylinositol 4,5-bisphosphate (PIP2), and culminates with the activation of IP3R in the ER. Conversely, SOCE is initiated in the ER by Ca2+-sensing stromal interaction molecule (STIM) proteins, which then interact with PM channels Orai1 and TRPC1 to activate Ca2+ entry. This review will address how ER-PM junctions serve a central role in agonist regulation of SOCE.
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Affiliation(s)
- Hwei Ling Ong
- Secretory Physiology Section, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda Maryland 20892
| | - Indu Suresh Ambudkar
- Secretory Physiology Section, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda Maryland 20892
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19
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Mo J, Xu Y, Wang X, Wei W, Zhao J. Exploiting the protein corona: coating of black phosphorus nanosheets enables macrophage polarization via calcium influx. NANOSCALE 2020; 12:1742-1748. [PMID: 31895379 DOI: 10.1039/c9nr08570j] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
Black phosphorus nanosheets (BPNSs) have substantially promoted biomedical nanotechnology due to their unique photothermal and chemotherapeutic properties. However, there is still a limited molecular understanding of the effects of bio-nano interfaces on BPNSs and the subsequent impacts on physiological systems. Here, it is shown that black phosphorus-corona complexes (BPCCs) could function as immune modulators to promote the polarization of macrophages. Mechanistically, BPCCs could interact with calmodulin to activate stromal interaction molecule 2 and facilitate Ca2+ influx in macrophages, which induced the activation of p38 and NF-κB and polarized M0 macrophages to the M1 phenotype. As a result, BPCC-activated macrophages show greater migration towards cancer cells, 1.3-1.9 times higher cellular cytotoxicity and effective phagocytosis of cancer cells. These findings offer insights into the development of potential and unique applications of corona on BPNSs in nanomedicine.
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Affiliation(s)
- Jianbin Mo
- State Key Laboratory of Coordination Chemistry, Chemistry and Biomedicine Innovation Center (ChemBIC), School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 201193, China.
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20
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Zhukovsky MA, Filograna A, Luini A, Corda D, Valente C. Protein Amphipathic Helix Insertion: A Mechanism to Induce Membrane Fission. Front Cell Dev Biol 2019; 7:291. [PMID: 31921835 PMCID: PMC6914677 DOI: 10.3389/fcell.2019.00291] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2019] [Accepted: 11/06/2019] [Indexed: 12/19/2022] Open
Abstract
One of the fundamental features of biomembranes is the ability to fuse or to separate. These processes called respectively membrane fusion and fission are central in the homeostasis of events such as those related to intracellular membrane traffic. Proteins that contain amphipathic helices (AHs) were suggested to mediate membrane fission via shallow insertion of these helices into the lipid bilayer. Here we analyze the AH-containing proteins that have been identified as essential for membrane fission and categorize them in few subfamilies, including small GTPases, Atg proteins, and proteins containing either the ENTH/ANTH- or the BAR-domain. AH-containing fission-inducing proteins may require cofactors such as additional proteins (e.g., lipid-modifying enzymes), or lipids (e.g., phosphatidylinositol 4,5-bisphosphate [PtdIns(4,5)P2], phosphatidic acid [PA], or cardiolipin). Both PA and cardiolipin possess a cone shape and a negative charge (-2) that favor the recruitment of the AHs of fission-inducing proteins. Instead, PtdIns(4,5)P2 is characterized by an high negative charge able to recruit basic residues of the AHs of fission-inducing proteins. Here we propose that the AHs of fission-inducing proteins contain sequence motifs that bind lipid cofactors; accordingly (K/R/H)(K/R/H)xx(K/R/H) is a PtdIns(4,5)P2-binding motif, (K/R)x6(F/Y) is a cardiolipin-binding motif, whereas KxK is a PA-binding motif. Following our analysis, we show that the AHs of many fission-inducing proteins possess five properties: (a) at least three basic residues on the hydrophilic side, (b) ability to oligomerize, (c) optimal (shallow) depth of insertion into the membrane, (d) positive cooperativity in membrane curvature generation, and (e) specific interaction with one of the lipids mentioned above. These lipid cofactors favor correct conformation, oligomeric state and optimal insertion depth. The most abundant lipid in a given organelle possessing high negative charge (more negative than -1) is usually the lipid cofactor in the fission event. Interestingly, naturally occurring mutations have been reported in AH-containing fission-inducing proteins and related to diseases such as centronuclear myopathy (amphiphysin 2), Charcot-Marie-Tooth disease (GDAP1), Parkinson's disease (α-synuclein). These findings add to the interest of the membrane fission process whose complete understanding will be instrumental for the elucidation of the pathogenesis of diseases involving mutations in the protein AHs.
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Affiliation(s)
- Mikhail A. Zhukovsky
- Institute of Biochemistry and Cell Biology, National Research Council, Naples, Italy
| | | | | | - Daniela Corda
- Institute of Biochemistry and Cell Biology, National Research Council, Naples, Italy
| | - Carmen Valente
- Institute of Biochemistry and Cell Biology, National Research Council, Naples, Italy
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21
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von Blume J, Hausser A. Lipid-dependent coupling of secretory cargo sorting and trafficking at the trans-Golgi network. FEBS Lett 2019; 593:2412-2427. [PMID: 31344259 PMCID: PMC8048779 DOI: 10.1002/1873-3468.13552] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2019] [Revised: 07/10/2019] [Accepted: 07/22/2019] [Indexed: 12/17/2022]
Abstract
In eukaryotic cells, the trans-Golgi network (TGN) serves as a platform for secretory cargo sorting and trafficking. In recent years, it has become evident that a complex network of lipid–lipid and lipid–protein interactions contributes to these key functions. This review addresses the role of lipids at the TGN with a particular emphasis on sphingolipids and diacylglycerol. We further highlight how these lipids couple secretory cargo sorting and trafficking for spatiotemporal coordination of protein transport to the plasma membrane.
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Affiliation(s)
- Julia von Blume
- Department of Cell Biology, Yale School of Medicine, New Haven, CT, USA.,Max Planck Institute of Biochemistry, Martinsried, Germany
| | - Angelika Hausser
- Institute of Cell Biology and Immunology, University of Stuttgart, Germany.,Stuttgart Research Center Systems Biology, University of Stuttgart, Germany
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22
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Emrich SM, Yoast RE, Xin P, Zhang X, Pathak T, Nwokonko R, Gueguinou MF, Subedi KP, Zhou Y, Ambudkar IS, Hempel N, Machaca K, Gill DL, Trebak M. Cross-talk between N-terminal and C-terminal domains in stromal interaction molecule 2 (STIM2) determines enhanced STIM2 sensitivity. J Biol Chem 2019; 294:6318-6332. [PMID: 30824535 DOI: 10.1074/jbc.ra118.006801] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2018] [Revised: 02/28/2019] [Indexed: 12/20/2022] Open
Abstract
Store-operated Ca2+ entry (SOCE) is a ubiquitous pathway for Ca2+ influx across the plasma membrane (PM). SOCE is mediated by the endoplasmic reticulum (ER)-associated Ca2+-sensing proteins stromal interaction molecule 1 (STIM1) and STIM2, which transition into an active conformation in response to ER Ca2+ store depletion, thereby interacting with and gating PM-associated ORAI1 channels. Although structurally homologous, STIM1 and STIM2 generate distinct Ca2+ signatures in response to varying strengths of agonist stimulation. The physiological functions of these Ca2+ signatures, particularly under native conditions, remain unclear. To investigate the structural properties distinguishing STIM1 and STIM2 activation of ORAI1 channels under native conditions, here we used CRISPR/Cas9 to generate STIM1-/-, STIM2-/-, and STIM1/2-/- knockouts in HEK293 and colorectal HCT116 cells. We show that depending on cell type, STIM2 can significantly sustain SOCE in response to maximal store depletion. Utilizing the SOCE modifier 2-aminoethoxydiphenyl borate (2-APB), we demonstrate that 2-APB-activated store-independent Ca2+ entry is mediated exclusively by endogenous STIM2. Using variants that either stabilize or disrupt intramolecular interactions of STIM C termini, we show that the increased flexibility of the STIM2 C terminus contributes to its selective store-independent activation by 2-APB. However, STIM1 variants with enhanced flexibility in the C terminus failed to support its store-independent activation. STIM1/STIM2 chimeric constructs indicated that coordination between N-terminal sensitivity and C-terminal flexibility is required for specific store-independent STIM2 activation. Our results clarify the structural determinants underlying activation of specific STIM isoforms, insights that are potentially useful for isoform-selective drug targeting.
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Affiliation(s)
- Scott M Emrich
- From the Departments of Cellular and Molecular Physiology and
| | - Ryan E Yoast
- From the Departments of Cellular and Molecular Physiology and
| | - Ping Xin
- From the Departments of Cellular and Molecular Physiology and
| | - Xuexin Zhang
- From the Departments of Cellular and Molecular Physiology and
| | | | - Robert Nwokonko
- From the Departments of Cellular and Molecular Physiology and
| | | | - Krishna P Subedi
- the Secretory Physiology Section, NIDCR, National Institutes of Health, Bethesda, Maryland 20892, and
| | - Yandong Zhou
- From the Departments of Cellular and Molecular Physiology and
| | - Indu S Ambudkar
- the Secretory Physiology Section, NIDCR, National Institutes of Health, Bethesda, Maryland 20892, and
| | - Nadine Hempel
- Pharmacology, Pennsylvania State University College of Medicine, Hershey, Pennsylvania 17033
| | - Khaled Machaca
- the Department of Physiology and Biophysics, Weill Cornell Medical College in Qatar, Education City, Qatar Foundation, P.O. Box 24144, Doha, Qatar
| | - Donald L Gill
- From the Departments of Cellular and Molecular Physiology and
| | - Mohamed Trebak
- From the Departments of Cellular and Molecular Physiology and
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23
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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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24
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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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25
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Tuning store-operated calcium entry to modulate Ca 2+-dependent physiological processes. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2018; 1866:1037-1045. [PMID: 30521873 DOI: 10.1016/j.bbamcr.2018.11.018] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/12/2018] [Revised: 11/28/2018] [Accepted: 11/29/2018] [Indexed: 01/10/2023]
Abstract
The intracellular calcium signaling processes are tightly regulated to ensure the generation of calcium signals with the specific spatiotemporal characteristics required for regulating various cell functions. Compartmentalization of the molecular components involved in the generation of these signals at discrete intracellular sites ensures the signaling specificity and transduction fidelity of the signal for regulating downstream effector processes. Store-operated calcium entry (SOCE) is ubiquitously present in cells and is critical for essential cell functions in a variety of tissues. SOCE is mediated via plasma membrane Ca2+ channels that are activated when luminal [Ca2+] of the endoplasmic reticulum ([Ca2+]ER) is decreased. The ER-resident stromal interaction molecules, STIM1 and STIM2, respond to decreases in [Ca2+]ER by undergoing conformational changes that cause them to aggregate at the cell periphery in ER-plasma membrane (ER-PM) junctions. At these sites, STIM proteins recruit Orai1 channels and trigger their activation. Importantly, the two STIM proteins concertedly modulate Orai1 function as well as the sensitivity of SOCE to ER-Ca2+ store depletion. Another family of plasma membrane Ca2+ channels, known as the Transient Receptor Potential Canonical (TRPC) channels (TRPC1-7) also contribute to sustained [Ca2+]i elevation. Although Ca2+ signals generated by these channels overlap with those of Orai1, they regulate distinct functions in the cells. Importantly, STIM1 is also required for plasma membrane localization and activation of some TRPCs. In this review, we will discuss various molecular components and factors that govern the activation, regulation and modulation of the Ca2+ signal generated by Ca2+ entry pathways in response to depletion of ER-Ca2+ stores. This article is part of a Special Issue entitled: ECS Meeting edited by Claus Heizmann, Joachim Krebs and Jacques Haiech.
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26
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Bulla M, Gyimesi G, Kim JH, Bhardwaj R, Hediger MA, Frieden M, Demaurex N. ORAI1 channel gating and selectivity is differentially altered by natural mutations in the first or third transmembrane domain. J Physiol 2018; 597:561-582. [PMID: 30382595 PMCID: PMC6332830 DOI: 10.1113/jp277079] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2018] [Accepted: 10/31/2018] [Indexed: 12/12/2022] Open
Abstract
KEY POINTS Gain-of-function mutations in the highly selective Ca2+ channel ORAI1 cause tubular aggregate myopathy (TAM) characterized by muscular pain, weakness and cramping. TAM-associated mutations in ORAI1 first and third transmembrane domain facilitate channel opening by STIM1, causing constitutive Ca2+ influx and increasing the currents evoked by Ca2+ store depletion. Mutation V107M additionally decreases the channel selectivity for Ca2+ ions and its inhibition by acidic pH, while mutation T184M does not alter the channel sensitivity to pH or to reactive oxygen species. The ORAI blocker GSK-7975A prevents the constitutive activity of TAM-associated channels and might be used in therapy for patients suffering from TAM. ABSTRACT Skeletal muscle differentiation relies on store-operated Ca2+ entry (SOCE) mediated by STIM proteins linking the depletion of endoplasmic/sarcoplasmic reticulum Ca2+ stores to the activation of membrane Ca2+ -permeable ORAI channels. Gain-of-function mutations in STIM1 or ORAI1 isoforms cause tubular aggregate myopathy (TAM), a skeletal muscle disorder with muscular pain, weakness and cramping. Here, we characterize two overactive ORAI1 mutants from patients with TAM: V107M and T184M, located in the first and third transmembrane domain of the channel. When ectopically expressed in HEK-293T cells or human primary myoblasts, the mutated channels increased basal and store-operated Ca2+ entry. The constitutive activity of V107M, L138F, T184M and P245L mutants was prevented by low concentrations of GSK-7975A while the G98S mutant was resistant to inhibition. Electrophysiological recordings confirmed ORAI1-V107M constitutive activity and revealed larger STIM1-gated V107M- and T184M-mediated currents with conserved fast and slow Ca2+ -dependent inactivation. Mutation V107M altered the channel selectivity for Ca2+ ions and conferred resistance to acidic inhibition. Ca2+ imaging and molecular dynamics simulations showed a preserved sensitivity of T184M to the negative regulation by reactive oxygen species. Both mutants were able to mediate SOCE in Stim1-/- /Stim2-/- mouse embryonic fibroblasts expressing the binding-deficient STIM1-F394H mutant, indicating a higher sensitivity for STIM1-mediated gating, with ORAI1-T184M gain-of-function being strictly dependent on STIM1. These findings provide new insights into the permeation and regulatory properties of ORAI1 mutants that might translate into therapies against diseases with gain-of-function mutations in ORAI1.
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Affiliation(s)
- M Bulla
- Department of Cell Physiology and Metabolism, University of Geneva, Geneva, Switzerland
| | - G Gyimesi
- Institute of Biochemistry and Molecular Medicine, University of Bern, Bern, Switzerland
| | - J H Kim
- Departments of Physiology and Global Medical Science, Yonsei University Wonju College of Medicine, Wonju, Republic of Korea.,Mitohormesis Research Center, Yonsei University Wonju College of Medicine, Wonju, Republic of Korea
| | - R Bhardwaj
- Institute of Biochemistry and Molecular Medicine, University of Bern, Bern, Switzerland
| | - M A Hediger
- Institute of Biochemistry and Molecular Medicine, University of Bern, Bern, Switzerland
| | - M Frieden
- Department of Cell Physiology and Metabolism, University of Geneva, Geneva, Switzerland
| | - N Demaurex
- Department of Cell Physiology and Metabolism, University of Geneva, Geneva, Switzerland
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Calcium store refilling and STIM activation in STIM- and Orai-deficient cell lines. Pflugers Arch 2018; 470:1555-1567. [PMID: 29934936 PMCID: PMC6153602 DOI: 10.1007/s00424-018-2165-5] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2018] [Revised: 05/24/2018] [Accepted: 06/07/2018] [Indexed: 12/02/2022]
Abstract
Mediated through the combined action of STIM proteins and Orai channels, store-operated Ca2+ entry (SOCE) functions ubiquitously among different cell types. The existence of multiple STIM and Orai genes has made it difficult to assign specific roles of each STIM and Orai homolog in mediating Ca2+ signals. Using CRISPR/Cas9 gene editing tools, we generated cells with both STIM or all three Orai homologs deleted and directly monitored store Ca2+ and Ca2+ signals. We found that unstimulated, SOCE null KO cells still retain 50~70% of ER Ca2+ stores of wildtype (wt) cells. After brief exposure to store-emptying conditions, acute refilling of ER Ca2+ stores was totally blocked in KO cells. However, after 24 h in culture, stores were eventually refilled. Thus, SOCE is critical for immediate refilling of ER Ca2+ but is dispensable for the maintenance of long-term ER Ca2+ homeostasis. Using the Orai null background triple Orai-KO cells, we examined the plasma membrane translocation properties of a series of truncated STIM1 variants. FRET analysis reveals that, even though PM tethering of STIM1 expedites the activation of STIM1 by facilitating its oligomerization, migration, and accumulation in ER-PM junctions, it is not required for the conformational switch, oligomerization, and clustering of STIM1. Even without overt puncta formation at ER-PM junctions, STIM11–491 and STIM11–666 could still rescue SOCE when expressed in STIM KO cells. Thus, ER-PM trapping and clustering of STIM molecules only facilitates the process of SOCE activation, but is not essential for the activation of Orai channels.
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28
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Huang TY, Lin YH, Chang HA, Yeh TY, Chang YH, Chen YF, Chen YC, Li CC, Chiu WT. STIM1 Knockout Enhances PDGF-Mediated Ca 2+ Signaling through Upregulation of the PDGFR⁻PLCγ⁻STIM2 Cascade. Int J Mol Sci 2018; 19:ijms19061799. [PMID: 29912163 PMCID: PMC6032054 DOI: 10.3390/ijms19061799] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2018] [Revised: 06/13/2018] [Accepted: 06/14/2018] [Indexed: 01/24/2023] Open
Abstract
Platelet-derived growth factor (PDGF) has mitogenic and chemotactic effects on fibroblasts. An increase in intracellular Ca2+ is one of the first events that occurs following the stimulation of PDGF receptors (PDGFRs). PDGF activates Ca2+ elevation by activating the phospholipase C gamma (PLCγ)-signaling pathway, resulting in ER Ca2+ release. Store-operated Ca2+ entry (SOCE) is the major form of extracellular Ca2+ influx following depletion of ER Ca2+ stores and stromal interaction molecule 1 (STIM1) is a key molecule in the regulation of SOCE. In this study, wild-type and STIM1 knockout mouse embryonic fibroblasts (MEF) cells were used to investigate the role of STIM1 in PDGF-induced Ca2+ oscillation and its functions in MEF cells. The unexpected findings suggest that STIM1 knockout enhances PDGFR–PLCγ–STIM2 signaling, which in turn increases PDGF-BB-induced Ca2+ elevation. Enhanced expressions of PDGFRs and PLCγ in STIM1 knockout cells induce Ca2+ release from the ER store through PLCγ–IP3 signaling. Moreover, STIM2 replaces STIM1 to act as the major ER Ca2+ sensor in activating SOCE. However, activation of PDGFRs also activate Akt, ERK, and JNK to regulate cellular functions, such as cell migration. These results suggest that alternative switchable pathways can be observed in cells, which act downstream of the growth factors that regulate Ca2+ signaling.
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Affiliation(s)
- Tzu-Yu Huang
- Department of Biomedical Engineering, National Cheng Kung University, Tainan 701, Taiwan.
| | - Yi-Hsin Lin
- Department of Biomedical Engineering, National Cheng Kung University, Tainan 701, Taiwan.
| | - Heng-Ai Chang
- Institute of Basic Medical Sciences, National Cheng Kung University, Tainan 701, Taiwan.
| | - Tzu-Ying Yeh
- Department of Biomedical Engineering, National Cheng Kung University, Tainan 701, Taiwan.
| | - Ya-Han Chang
- Department of Biomedical Engineering, National Cheng Kung University, Tainan 701, Taiwan.
| | - Yi-Fan Chen
- Institute of Basic Medical Sciences, National Cheng Kung University, Tainan 701, Taiwan.
| | - Ying-Chi Chen
- Department of Biomedical Engineering, National Cheng Kung University, Tainan 701, Taiwan.
| | - Chun-Chun Li
- Department of Life Sciences, National Cheng Kung University, Tainan 701, Taiwan.
| | - Wen-Tai Chiu
- Department of Biomedical Engineering, National Cheng Kung University, Tainan 701, Taiwan.
- Institute of Basic Medical Sciences, National Cheng Kung University, Tainan 701, Taiwan.
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29
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Interplay between ER Ca 2+ Binding Proteins, STIM1 and STIM2, Is Required for Store-Operated Ca 2+ Entry. Int J Mol Sci 2018; 19:ijms19051522. [PMID: 29783744 PMCID: PMC5983841 DOI: 10.3390/ijms19051522] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2018] [Revised: 05/14/2018] [Accepted: 05/15/2018] [Indexed: 01/04/2023] Open
Abstract
Store-operated calcium entry (SOCE), a fundamentally important homeostatic and Ca2+ signaling pathway in many types of cells, is activated by the direct interaction of stromal interaction molecule 1 (STIM1), an endoplasmic reticulum (ER) Ca2+-binding protein, with Ca2+-selective Orai1 channels localized in the plasma membrane. While much is known about the regulation of SOCE by STIM1, the role of stromal interaction molecule 2 (STIM2) in SOCE remains incompletely understood. Here, using clustered regularly interspaced short palindromic repeats -CRISPR associated protein 9 (CRISPR-Cas9) genomic editing and molecular imaging, we investigated the function of STIM2 in NIH 3T3 fibroblast and αT3 cell SOCE. We found that deletion of Stim2 expression reduced SOCE by more than 90% in NIH 3T3 cells. STIM1 expression levels were unaffected in the Stim2 null cells. However, quantitative confocal fluorescence imaging demonstrated that in the absence of Stim2 expression, STIM1 did not translocate or form punctae in plasma membrane-associated ER membrane (PAM) junctions following ER Ca2+ store depletion. Fluorescence resonance energy transfer (FRET) imaging of intact, living cells revealed that the formation of STIM1 and Orai1 complexes in PAM nanodomains was significantly reduced in the Stim2 knockout cells. Our findings indicate that STIM2 plays an essential role in regulating SOCE in NIH 3T3 and αT3 cells and suggests that dynamic interplay between STIM1 and STIM2 induced by ER Ca2+ store discharge is necessary for STIM1 translocation, its interaction with Orai1, and activation of SOCE.
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30
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Subedi KP, Ong HL, Son GY, Liu X, Ambudkar IS. STIM2 Induces Activated Conformation of STIM1 to Control Orai1 Function in ER-PM Junctions. Cell Rep 2018; 23:522-534. [DOI: 10.1016/j.celrep.2018.03.065] [Citation(s) in RCA: 45] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2017] [Revised: 02/12/2018] [Accepted: 03/15/2018] [Indexed: 02/07/2023] Open
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Lopez JJ, Albarrán L, Jardín I, Sanchez-Collado J, Redondo PC, Bermejo N, Bobe R, Smani T, Rosado JA. Filamin A Modulates Store-Operated Ca2+Entry by Regulating STIM1 (Stromal Interaction Molecule 1)–Orai1 Association in Human Platelets. Arterioscler Thromb Vasc Biol 2018; 38:386-397. [DOI: 10.1161/atvbaha.117.310139] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2017] [Accepted: 12/13/2017] [Indexed: 12/23/2022]
Affiliation(s)
- Jose J. Lopez
- From the Department of Physiology, University of Extremadura, Cáceres, Spain (J.J.L., L.A., I.J., J.S.-C., P.C.R., J.A.R.); Department of Hematology, Hospital San Pedro de Alcantara, Cáceres, Spain (N.B.); INSERM Unité Mixte de Recherche-Santé 1176, Université Paris-Sud, Université Paris-Saclay, Le Kremlin-Bicêtre, France (R.B.); and Department of Medical Physiology and Biophysics, Institute of Biomedicine of Seville, University of Seville, Spain (T.S.)
| | - Letizia Albarrán
- From the Department of Physiology, University of Extremadura, Cáceres, Spain (J.J.L., L.A., I.J., J.S.-C., P.C.R., J.A.R.); Department of Hematology, Hospital San Pedro de Alcantara, Cáceres, Spain (N.B.); INSERM Unité Mixte de Recherche-Santé 1176, Université Paris-Sud, Université Paris-Saclay, Le Kremlin-Bicêtre, France (R.B.); and Department of Medical Physiology and Biophysics, Institute of Biomedicine of Seville, University of Seville, Spain (T.S.)
| | - Isaac Jardín
- From the Department of Physiology, University of Extremadura, Cáceres, Spain (J.J.L., L.A., I.J., J.S.-C., P.C.R., J.A.R.); Department of Hematology, Hospital San Pedro de Alcantara, Cáceres, Spain (N.B.); INSERM Unité Mixte de Recherche-Santé 1176, Université Paris-Sud, Université Paris-Saclay, Le Kremlin-Bicêtre, France (R.B.); and Department of Medical Physiology and Biophysics, Institute of Biomedicine of Seville, University of Seville, Spain (T.S.)
| | - Jose Sanchez-Collado
- From the Department of Physiology, University of Extremadura, Cáceres, Spain (J.J.L., L.A., I.J., J.S.-C., P.C.R., J.A.R.); Department of Hematology, Hospital San Pedro de Alcantara, Cáceres, Spain (N.B.); INSERM Unité Mixte de Recherche-Santé 1176, Université Paris-Sud, Université Paris-Saclay, Le Kremlin-Bicêtre, France (R.B.); and Department of Medical Physiology and Biophysics, Institute of Biomedicine of Seville, University of Seville, Spain (T.S.)
| | - Pedro C. Redondo
- From the Department of Physiology, University of Extremadura, Cáceres, Spain (J.J.L., L.A., I.J., J.S.-C., P.C.R., J.A.R.); Department of Hematology, Hospital San Pedro de Alcantara, Cáceres, Spain (N.B.); INSERM Unité Mixte de Recherche-Santé 1176, Université Paris-Sud, Université Paris-Saclay, Le Kremlin-Bicêtre, France (R.B.); and Department of Medical Physiology and Biophysics, Institute of Biomedicine of Seville, University of Seville, Spain (T.S.)
| | - Nuria Bermejo
- From the Department of Physiology, University of Extremadura, Cáceres, Spain (J.J.L., L.A., I.J., J.S.-C., P.C.R., J.A.R.); Department of Hematology, Hospital San Pedro de Alcantara, Cáceres, Spain (N.B.); INSERM Unité Mixte de Recherche-Santé 1176, Université Paris-Sud, Université Paris-Saclay, Le Kremlin-Bicêtre, France (R.B.); and Department of Medical Physiology and Biophysics, Institute of Biomedicine of Seville, University of Seville, Spain (T.S.)
| | - Regis Bobe
- From the Department of Physiology, University of Extremadura, Cáceres, Spain (J.J.L., L.A., I.J., J.S.-C., P.C.R., J.A.R.); Department of Hematology, Hospital San Pedro de Alcantara, Cáceres, Spain (N.B.); INSERM Unité Mixte de Recherche-Santé 1176, Université Paris-Sud, Université Paris-Saclay, Le Kremlin-Bicêtre, France (R.B.); and Department of Medical Physiology and Biophysics, Institute of Biomedicine of Seville, University of Seville, Spain (T.S.)
| | - Tarik Smani
- From the Department of Physiology, University of Extremadura, Cáceres, Spain (J.J.L., L.A., I.J., J.S.-C., P.C.R., J.A.R.); Department of Hematology, Hospital San Pedro de Alcantara, Cáceres, Spain (N.B.); INSERM Unité Mixte de Recherche-Santé 1176, Université Paris-Sud, Université Paris-Saclay, Le Kremlin-Bicêtre, France (R.B.); and Department of Medical Physiology and Biophysics, Institute of Biomedicine of Seville, University of Seville, Spain (T.S.)
| | - Juan A. Rosado
- From the Department of Physiology, University of Extremadura, Cáceres, Spain (J.J.L., L.A., I.J., J.S.-C., P.C.R., J.A.R.); Department of Hematology, Hospital San Pedro de Alcantara, Cáceres, Spain (N.B.); INSERM Unité Mixte de Recherche-Santé 1176, Université Paris-Sud, Université Paris-Saclay, Le Kremlin-Bicêtre, France (R.B.); and Department of Medical Physiology and Biophysics, Institute of Biomedicine of Seville, University of Seville, Spain (T.S.)
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32
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Nelson HA, Roe MW. Molecular physiology and pathophysiology of stromal interaction molecules. Exp Biol Med (Maywood) 2018; 243:451-472. [PMID: 29363328 DOI: 10.1177/1535370218754524] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Ca2+ release from the endoplasmic reticulum is an important component of Ca2+ signal transduction that controls numerous physiological processes in eukaryotic cells. Release of Ca2+ from the endoplasmic reticulum is coupled to the activation of store-operated Ca2+ entry into cells. Store-operated Ca2+ entry provides Ca2+ for replenishing depleted endoplasmic reticulum Ca2+ stores and a Ca2+ signal that regulates Ca2+-dependent intracellular biochemical events. Central to connecting discharge of endoplasmic reticulum Ca2+ stores following G protein-coupled receptor activation with the induction of store-operated Ca2+ entry are stromal interaction molecules (STIM1 and STIM2). These highly homologous endoplasmic reticulum transmembrane proteins function as sensors of the Ca2+ concentration within the endoplasmic reticulum lumen and activators of Ca2+ release-activated Ca2+ channels. Emerging evidence indicates that in addition to their role in Ca2+ release-activated Ca2+ channel gating and store-operated Ca2+ entry, STIM1 and STIM2 regulate other cellular signaling events. Recent studies have shown that disruption of STIM expression and function is associated with the pathogenesis of several diseases including autoimmune disorders, cancer, cardiovascular disease, and myopathies. Here, we provide an overview of the latest developments in the molecular physiology and pathophysiology of STIM1 and STIM2. Impact statement Intracellular Ca2+ signaling is a fundamentally important regulator of cell physiology. Recent studies have revealed that Ca2+-binding stromal interaction molecules (Stim1 and Stim2) expressed in the membrane of the endoplasmic reticulum (ER) are essential components of eukaryote Ca2+ signal transduction that control the activity of ion channels and other signaling effectors present in the plasma membrane. This review summarizes the most recent information on the molecular physiology and pathophysiology of stromal interaction molecules. We anticipate that the work presented in our review will provide new insights into molecular interactions that participate in interorganelle signaling crosstalk, cell function, and the pathogenesis of human diseases.
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Affiliation(s)
- Heather A Nelson
- 1 Department of Cell and Developmental Biology, 12302 SUNY Upstate Medical University, Syracuse, NY 13210, USA
| | - Michael W Roe
- 1 Department of Cell and Developmental Biology, 12302 SUNY Upstate Medical University, Syracuse, NY 13210, USA.,2 Department of Medicine, 12302 SUNY Upstate Medical University, Syracuse, NY 13210, USA
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33
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Mignen O, Constantin B, Potier-Cartereau M, Penna A, Gautier M, Guéguinou M, Renaudineau Y, Shoji KF, Félix R, Bayet E, Buscaglia P, Debant M, Chantôme A, Vandier C. Constitutive calcium entry and cancer: updated views and insights. EUROPEAN BIOPHYSICS JOURNAL: EBJ 2017; 46:395-413. [PMID: 28516266 DOI: 10.1007/s00249-017-1216-8] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/15/2016] [Revised: 03/10/2017] [Accepted: 04/26/2017] [Indexed: 12/20/2022]
Abstract
Tight control of basal cytosolic Ca2+ concentration is essential for cell survival and to fine-tune Ca2+-dependent cell functions. A way to control this basal cytosolic Ca2+ concentration is to regulate membrane Ca2+ channels including store-operated Ca2+ channels and secondary messenger-operated channels linked to G-protein-coupled or tyrosine kinase receptor activation. Orai, with or without its reticular STIM partner and Transient Receptor Potential (TRP) proteins, were considered to be the main Ca2+ channels involved. It is well accepted that, in response to cell stimulation, opening of these Ca2+ channels contributes to Ca2+ entry and the transient increase in cytosolic Ca2+ concentration involved in intracellular signaling. However, in various experimental conditions, Ca2+ entry and/or Ca2+ currents can be recorded at rest, without application of any experimental stimulation. This led to the proposition that some plasma membrane Ca2+ channels are already open/activated in basal condition, contributing therefore to constitutive Ca2+ entry. This article focuses on direct and indirect observations supporting constitutive activity of channels belonging to the Orai and TRP families and on the mechanisms underlying their basal/constitutive activities.
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Affiliation(s)
- Olivier Mignen
- Inserm UMR 1078 IFR148 Université de Bretagne Occidentale, Brest, France
- Network "Ion Channels and Cancer-Canceropôle Grand Ouest", (IC-CGO), Grand Ouest, France
| | - Bruno Constantin
- STIM, ERL 7368 CNRS Université de Poitiers, Poitiers, France
- Network "Ion Channels and Cancer-Canceropôle Grand Ouest", (IC-CGO), Grand Ouest, France
| | - Marie Potier-Cartereau
- Inserm/University of Tours U1069, Nutrition-Croissance et Cancer (N2C), 37032, Tours, France
- Network "Ion Channels and Cancer-Canceropôle Grand Ouest", (IC-CGO), Grand Ouest, France
| | - Aubin Penna
- IRSET, Inserm U1085, University of Rennes 1, 36043, Rennes, France
- Network "Ion Channels and Cancer-Canceropôle Grand Ouest", (IC-CGO), Grand Ouest, France
| | - Mathieu Gautier
- EA4667, Université de Picardie Jules Verne, 80039, Amiens, France
| | - Maxime Guéguinou
- Inserm/University of Tours U1069, Nutrition-Croissance et Cancer (N2C), 37032, Tours, France
- Network "Ion Channels and Cancer-Canceropôle Grand Ouest", (IC-CGO), Grand Ouest, France
| | - Yves Renaudineau
- EA 2216, Inserm ESPRI, ERI 29, Brest, France
- Network "Ion Channels and Cancer-Canceropôle Grand Ouest", (IC-CGO), Grand Ouest, France
| | - Kenji F Shoji
- IRSET, Inserm U1085, University of Rennes 1, 36043, Rennes, France
- Network "Ion Channels and Cancer-Canceropôle Grand Ouest", (IC-CGO), Grand Ouest, France
| | - Romain Félix
- Inserm/University of Tours U1069, Nutrition-Croissance et Cancer (N2C), 37032, Tours, France
- Network "Ion Channels and Cancer-Canceropôle Grand Ouest", (IC-CGO), Grand Ouest, France
| | - Elsa Bayet
- STIM, ERL 7368 CNRS Université de Poitiers, Poitiers, France
- IRSET, Inserm U1085, University of Rennes 1, 36043, Rennes, France
- Network "Ion Channels and Cancer-Canceropôle Grand Ouest", (IC-CGO), Grand Ouest, France
| | - Paul Buscaglia
- Inserm UMR 1078 IFR148 Université de Bretagne Occidentale, Brest, France
- Network "Ion Channels and Cancer-Canceropôle Grand Ouest", (IC-CGO), Grand Ouest, France
| | - Marjolaine Debant
- Inserm UMR 1078 IFR148 Université de Bretagne Occidentale, Brest, France
- EA 2216, Inserm ESPRI, ERI 29, Brest, France
- Network "Ion Channels and Cancer-Canceropôle Grand Ouest", (IC-CGO), Grand Ouest, France
| | - Aurélie Chantôme
- Inserm/University of Tours U1069, Nutrition-Croissance et Cancer (N2C), 37032, Tours, France
- Network "Ion Channels and Cancer-Canceropôle Grand Ouest", (IC-CGO), Grand Ouest, France
| | - Christophe Vandier
- Inserm/University of Tours U1069, Nutrition-Croissance et Cancer (N2C), 37032, Tours, France.
- Network "Ion Channels and Cancer-Canceropôle Grand Ouest", (IC-CGO), Grand Ouest, France.
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Berna-Erro A, Jardin I, Salido GM, Rosado JA. Role of STIM2 in cell function and physiopathology. J Physiol 2017; 595:3111-3128. [PMID: 28087881 DOI: 10.1113/jp273889] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2016] [Accepted: 01/03/2017] [Indexed: 01/01/2023] Open
Abstract
An endoplasmic reticulum (ER)-resident protein that regulates cytosolic and ER free-Ca2+ concentration by induction of store-operated calcium entry: that is the original definition of STIM2 and its function. While its activity strongly depends on the amount of calcium stored in the ER, its function goes further, to intracellular signalling and gene expression. Initially under-studied owing to the prominent function of STIM1, STIM2 came to be regarded as vital in mice, gradually emerging as an important player in the nervous system, and cooperating with STIM1 in the immune system. STIM2 has also been proposed as a relevant player in pathological conditions related to ageing, Alzheimer's and Huntington's diseases, autoimmune disorders and cancer. The discovery of additional functions, together with new splicing forms with opposite roles, has clarified existing controversies about STIM2 function in SOCE. With STIM2 being essential for life, but apparently not for development, newly available data demonstrate a complex and still intriguing behaviour that this review summarizes, updating current knowledge of STIM2 function.
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Affiliation(s)
- Alejandro Berna-Erro
- Laboratory of Molecular Physiology and Channelopathies, Department of Experimental and Health Sciences, Universitat Pompeu Fabra, 08003, Barcelona, Spain
| | - Isaac Jardin
- Department of Physiology (Cell Physiology Research Group), University of Extremadura, 10003, Cáceres, Spain
| | - Gines M Salido
- Department of Physiology (Cell Physiology Research Group), University of Extremadura, 10003, Cáceres, Spain
| | - Juan A Rosado
- Department of Physiology (Cell Physiology Research Group), University of Extremadura, 10003, Cáceres, Spain
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35
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Subedi KP, Ong HL, Ambudkar IS. Assembly of ER-PM Junctions: A Critical Determinant in the Regulation of SOCE and TRPC1. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2017; 981:253-276. [PMID: 29594865 DOI: 10.1007/978-3-319-55858-5_11] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Store-operated calcium entry (SOCE), a unique plasma membrane Ca2+ entry mechanism, is activated when ER-[Ca2+] is decreased. SOCE is mediated via the primary channel, Orai1, as well as others such as TRPC1. STIM1 and STIM2 are ER-Ca2+ sensor proteins that regulate Orai1 and TRPC1. SOCE requires assembly of STIM proteins with the plasma membrane channels which occurs within distinct regions in the cell that have been termed as endoplasmic reticulum (ER)-plasma membrane (PM) junctions. The PM and ER are in close proximity to each other within this region, which allows STIM1 in the ER to interact with and activate either Orai1 or TRPC1 in the plasma membrane. Activation and regulation of SOCE involves dynamic assembly of various components that are involved in mediating Ca2+ entry as well as those that determine the formation and stabilization of the junctions. These components include proteins in the cytosol, ER and PM, as well as lipids in the PM. Recent studies have also suggested that SOCE and its components are compartmentalized within ER-PM junctions and that this process might require remodeling of the plasma membrane lipids and reorganization of structural and scaffolding proteins. Such compartmentalization leads to the generation of spatially- and temporally-controlled Ca2+signals that are critical for regulating many downstream cellular functions.
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Affiliation(s)
- Krishna P Subedi
- Secretory Physiology Section, Molecular Physiology and Therapeutics Branch, NIDCR, NIH, Bethesda, MD, USA
| | - Hwei Ling Ong
- Secretory Physiology Section, Molecular Physiology and Therapeutics Branch, NIDCR, NIH, Bethesda, MD, USA
| | - Indu S Ambudkar
- Secretory Physiology Section, Molecular Physiology and Therapeutics Branch, NIDCR, NIH, Bethesda, MD, USA.
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From Stores to Sinks: Structural Mechanisms of Cytosolic Calcium Regulation. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2017; 981:215-251. [PMID: 29594864 DOI: 10.1007/978-3-319-55858-5_10] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/08/2022]
Abstract
All eukaryotic cells have adapted the use of the calcium ion (Ca2+) as a universal signaling element through the evolution of a toolkit of Ca2+ sensor, buffer and effector proteins. Among these toolkit components, integral and peripheral proteins decorate biomembranes and coordinate the movement of Ca2+ between compartments, sense these concentration changes and elicit physiological signals. These changes in compartmentalized Ca2+ levels are not mutually exclusive as signals propagate between compartments. For example, agonist induced surface receptor stimulation can lead to transient increases in cytosolic Ca2+ sourced from endoplasmic reticulum (ER) stores; the decrease in ER luminal Ca2+ can subsequently signal the opening surface channels which permit the movement of Ca2+ from the extracellular space to the cytosol. Remarkably, the minuscule compartments of mitochondria can function as significant cytosolic Ca2+ sinks by taking up Ca2+ in a coordinated manner. In non-excitable cells, inositol 1,4,5 trisphosphate receptors (IP3Rs) on the ER respond to surface receptor stimulation; stromal interaction molecules (STIMs) sense the ER luminal Ca2+ depletion and activate surface Orai1 channels; surface Orai1 channels selectively permit the movement of Ca2+ from the extracellular space to the cytosol; uptake of Ca2+ into the matrix through the mitochondrial Ca2+ uniporter (MCU) further shapes the cytosolic Ca2+ levels. Recent structural elucidations of these key Ca2+ toolkit components have improved our understanding of how they function to orchestrate precise cytosolic Ca2+ levels for specific physiological responses. This chapter reviews the atomic-resolution structures of IP3R, STIM1, Orai1 and MCU elucidated by X-ray crystallography, electron microscopy and NMR and discusses the mechanisms underlying their biological functions in their respective compartments within the cell.
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Niemeyer BA. The STIM-Orai Pathway: Regulation of STIM and Orai by Thiol Modifications. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2017; 993:99-116. [PMID: 28900911 DOI: 10.1007/978-3-319-57732-6_6] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Cysteines are among the least abundant amino acids found in proteins. Due to their unique nucleophilic thiol group, they are able to undergo a broad range of chemical modifications besides their known role in disulfide formation, such as S-sulfenylation (-SOH), S-sulfinylation (-SO(2)H), S-sufonylation (-SO(3)H), S-glutathionylation (-SSG), and S-sulfhydration (-SSH), among others. These posttranslational modifications can be irreversible and act as transitional modifiers or as reversible on-off switches for the function of proteins. Disturbances of the redox homeostasis, for example, in situations of increased oxidative stress, can contribute to a range of diseases. Because Ca2+ signaling mediated by store-operated calcium entry (SOCE) is involved in a plethora of cellular responses, the cross-talk between reactive oxygen species (ROS) and Ca2+ is critical for homeostatic control. Identification of calcium regulatory protein targets of thiol redox modifications is needed to understand their role in biology and disease.
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Affiliation(s)
- Barbara A Niemeyer
- Molecular Biophysics, Center for Integrative Physiology and Molecular Medicine, Saarland University, Homburg, Germany.
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Bhardwaj R, Hediger MA, Demaurex N. Redox modulation of STIM-ORAI signaling. Cell Calcium 2016; 60:142-52. [DOI: 10.1016/j.ceca.2016.03.006] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2016] [Accepted: 03/08/2016] [Indexed: 12/14/2022]
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Ong HL, Ambudkar IS. Molecular determinants of TRPC1 regulation within ER–PM junctions. Cell Calcium 2015; 58:376-86. [DOI: 10.1016/j.ceca.2015.03.008] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2015] [Revised: 03/18/2015] [Accepted: 03/19/2015] [Indexed: 11/30/2022]
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Abstract
Store-operated calcium channels (SOCs) are a major pathway for calcium signaling in virtually all metozoan cells and serve a wide variety of functions ranging from gene expression, motility, and secretion to tissue and organ development and the immune response. SOCs are activated by the depletion of Ca(2+) from the endoplasmic reticulum (ER), triggered physiologically through stimulation of a diverse set of surface receptors. Over 15 years after the first characterization of SOCs through electrophysiology, the identification of the STIM proteins as ER Ca(2+) sensors and the Orai proteins as store-operated channels has enabled rapid progress in understanding the unique mechanism of store-operate calcium entry (SOCE). Depletion of Ca(2+) from the ER causes STIM to accumulate at ER-plasma membrane (PM) junctions where it traps and activates Orai channels diffusing in the closely apposed PM. Mutagenesis studies combined with recent structural insights about STIM and Orai proteins are now beginning to reveal the molecular underpinnings of these choreographic events. This review describes the major experimental advances underlying our current understanding of how ER Ca(2+) depletion is coupled to the activation of SOCs. Particular emphasis is placed on the molecular mechanisms of STIM and Orai activation, Orai channel properties, modulation of STIM and Orai function, pharmacological inhibitors of SOCE, and the functions of STIM and Orai in physiology and disease.
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Affiliation(s)
- Murali Prakriya
- Department of Pharmacology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois; and Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, California
| | - Richard S Lewis
- Department of Pharmacology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois; and Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, California
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Store-operated calcium entry: Mechanisms and modulation. Biochem Biophys Res Commun 2015; 460:40-9. [PMID: 25998732 DOI: 10.1016/j.bbrc.2015.02.110] [Citation(s) in RCA: 150] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2015] [Accepted: 02/20/2015] [Indexed: 11/22/2022]
Abstract
Store-operated calcium entry is a central mechanism in cellular calcium signalling and in maintaining cellular calcium balance. This review traces the history of research on store-operated calcium entry, the discovery of STIM and ORAI as central players in calcium entry, and the role of STIM and ORAI in biology and human disease. It describes current knowledge of the basic mechanism of STIM-ORAI signalling and of the varied mechanisms by which STIM-ORAI signalling can be modulated.
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Abstract
The regulatory protein STIM1 controls gating of the Ca(2+) channel ORAI1 by a direct protein-protein interaction. Because STIM1 is anchored in the ER membrane and ORAI1 is in the plasma membrane, the STIM-ORAI pathway can support Ca(2+) influx only where the two membranes come into close apposition, effectively demarcating a microdomain for Ca(2+) signalling. This review begins with a brief summary of the STIM-ORAI pathway of store-operated Ca(2+) influx, then turns to the special geometry of the STIM-ORAI microdomain and the expected characteristics of the microdomain Ca(2+) signal. A final section of the review seeks to place the STIM-ORAI microdomain into a broader context of cellular Ca(2+) signalling.
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Affiliation(s)
- Patrick G Hogan
- La Jolla Institute for Allergy & Immunology, La Jolla, CA 92037, USA.
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Miederer AM, Alansary D, Schwär G, Lee PH, Jung M, Helms V, Niemeyer BA. A STIM2 splice variant negatively regulates store-operated calcium entry. Nat Commun 2015; 6:6899. [PMID: 25896806 PMCID: PMC4411291 DOI: 10.1038/ncomms7899] [Citation(s) in RCA: 94] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2014] [Accepted: 03/11/2015] [Indexed: 02/01/2023] Open
Abstract
Cellular homeostasis relies upon precise regulation of Ca(2+) concentration. Stromal interaction molecule (STIM) proteins regulate store-operated calcium entry (SOCE) by sensing Ca(2+) concentration in the ER and forming oligomers to trigger Ca(2+) entry through plasma membrane-localized Orai1 channels. Here we characterize a STIM2 splice variant, STIM2.1, which retains an additional exon within the region encoding the channel-activating domain. Expression of STIM2.1 is ubiquitous but its abundance relative to the more common STIM2.2 variant is dependent upon cell type and highest in naive T cells. STIM2.1 knockdown increases SOCE in naive CD4(+) T cells, whereas knockdown of STIM2.2 decreases SOCE. Conversely, overexpression of STIM2.1, but not STIM2.2, decreases SOCE, indicating its inhibitory role. STIM2.1 interaction with Orai1 is impaired and prevents Orai1 activation, but STIM2.1 shows increased affinity towards calmodulin. Our results imply STIM2.1 as an additional player tuning Orai1 activation in vivo.
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Affiliation(s)
- Anna-Maria Miederer
- Molecular Biophysics, Center for Integrative Physiology and Molecular Medicine (CIPMM), School of Medicine, Saarland University, Building 48, Homburg 66421, Germany
| | - Dalia Alansary
- Molecular Biophysics, Center for Integrative Physiology and Molecular Medicine (CIPMM), School of Medicine, Saarland University, Building 48, Homburg 66421, Germany
| | - Gertrud Schwär
- Molecular Biophysics, Center for Integrative Physiology and Molecular Medicine (CIPMM), School of Medicine, Saarland University, Building 48, Homburg 66421, Germany
- Department of Biophysics, Center for Integrative Physiology and Molecular Medicine (CIPMM), School of Medicine, Saarland University, Homburg 66421, Germany
| | - Po-Hsien Lee
- Center for Bioinformatics, Saarland University, Campus E2 1, R. 315, PO Box 151150, Saarbrücken 66041, Germany
| | - Martin Jung
- Department of Medical Biochemistry and Molecular Biology, Saarland University, Building 44, Homburg 66421, Germany
| | - Volkhard Helms
- Center for Bioinformatics, Saarland University, Campus E2 1, R. 315, PO Box 151150, Saarbrücken 66041, Germany
| | - Barbara A. Niemeyer
- Molecular Biophysics, Center for Integrative Physiology and Molecular Medicine (CIPMM), School of Medicine, Saarland University, Building 48, Homburg 66421, Germany
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Ong HL, de Souza LB, Zheng C, Cheng KT, Liu X, Goldsmith CM, Feske S, Ambudkar IS. STIM2 enhances receptor-stimulated Ca²⁺ signaling by promoting recruitment of STIM1 to the endoplasmic reticulum-plasma membrane junctions. Sci Signal 2015; 8:ra3. [PMID: 25587190 DOI: 10.1126/scisignal.2005748] [Citation(s) in RCA: 77] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
A central component of receptor-evoked Ca(2+) signaling is store-operated Ca(2+) entry (SOCE), which is activated by the assembly of STIM1-Orai1 channels in endoplasmic reticulum (ER) and plasma membrane (PM) (ER-PM) junctions in response to depletion of ER Ca(2+). We report that STIM2 enhances agonist-mediated activation of SOCE by promoting STIM1 clustering in ER-PM junctions at low stimulus intensities. Targeted deletion of STIM2 in mouse salivary glands diminished fluid secretion in vivo and SOCE activation in dispersed salivary acinar cells stimulated with low concentrations of muscarinic receptor agonists. STIM2 knockdown in human embryonic kidney (HEK) 293 cells diminished agonist-induced Ca(2+) signaling and nuclear translocation of NFAT (nuclear factor of activated T cells). STIM2 lacking five carboxyl-terminal amino acid residues did not promote formation of STIM1 puncta at low concentrations of agonist, whereas coexpression of STIM2 with STIM1 mutant lacking the polybasic region STIM1ΔK resulted in co-clustering of both proteins. Together, our findings suggest that STIM2 recruits STIM1 to ER-PM junctions at low stimulus intensities when ER Ca(2+) stores are mildly depleted, thus increasing the sensitivity of Ca(2+) signaling to agonists.
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Affiliation(s)
- Hwei Ling Ong
- Secretory Physiology Section, Molecular Physiology and Therapeutics Branch, National Institute of Dental and Craniofacial Research (NIDCR), National Institutes of Health (NIH), Bethesda, MD 20892, USA
| | - Lorena Brito de Souza
- Secretory Physiology Section, Molecular Physiology and Therapeutics Branch, National Institute of Dental and Craniofacial Research (NIDCR), National Institutes of Health (NIH), Bethesda, MD 20892, USA
| | - Changyu Zheng
- Translational Research Core, Molecular Physiology and Therapeutics Branch, NIDCR, NIH, Bethesda, MD 20892, USA
| | - Kwong Tai Cheng
- Department of Pharmacology, College of Medicine, University of Illinois at Chicago, Chicago, IL 60612, USA
| | - Xibao Liu
- Secretory Physiology Section, Molecular Physiology and Therapeutics Branch, National Institute of Dental and Craniofacial Research (NIDCR), National Institutes of Health (NIH), Bethesda, MD 20892, USA
| | - Corinne M Goldsmith
- Translational Research Core, Molecular Physiology and Therapeutics Branch, NIDCR, NIH, Bethesda, MD 20892, USA
| | - Stefan Feske
- Department of Pathology, New York University Langone Medical Center, New York, NY 10016, USA
| | - Indu S Ambudkar
- Secretory Physiology Section, Molecular Physiology and Therapeutics Branch, National Institute of Dental and Craniofacial Research (NIDCR), National Institutes of Health (NIH), Bethesda, MD 20892, USA.
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Ambudkar IS. Ca²⁺ signaling and regulation of fluid secretion in salivary gland acinar cells. Cell Calcium 2014; 55:297-305. [PMID: 24646566 DOI: 10.1016/j.ceca.2014.02.009] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2014] [Revised: 02/10/2014] [Accepted: 02/11/2014] [Indexed: 01/04/2023]
Abstract
Neurotransmitter stimulation of plasma membrane receptors stimulates salivary gland fluid secretion via a complex process that is determined by coordinated temporal and spatial regulation of several Ca(2+) signaling processes as well as ion flux systems. Studies over the past four decades have demonstrated that Ca(2+) is a critical factor in the control of salivary gland function. Importantly, critical components of this process have now been identified, including plasma membrane receptors, calcium channels, and regulatory proteins. The key event in activation of fluid secretion is an increase in intracellular [Ca(2+)] ([Ca(2+)]i) triggered by IP3-induced release of Ca(2+) from ER via the IP3R. This increase regulates the ion fluxes required to drive vectorial fluid secretion. IP3Rs determine the site of initiation and the pattern of [Ca(2+)]i signal in the cell. However, Ca(2+) entry into the cell is required to sustain the elevation of [Ca(2+)]i and fluid secretion. This Ca(2+) influx pathway, store-operated calcium influx pathway (SOCE), has been studied in great detail and the regulatory mechanisms as well as key molecular components have now been identified. Orai1, TRPC1, and STIM1 are critical components of SOCE and among these, Ca(2+) entry via TRPC1 is a major determinant of fluid secretion. The receptor-evoked Ca(2+) signal in salivary gland acinar cells is unique in that it starts at the apical pole and then rapidly increases across the cell. The basis for the polarized Ca(2+) signal can be ascribed to the polarized arrangement of the Ca(2+) channels, transporters, and signaling proteins. Distinct localization of these proteins in the cell suggests compartmentalization of Ca(2+) signals during regulation of fluid secretion. This chapter will discuss new concepts and findings regarding the polarization and control of Ca(2+) signals in the regulation of fluid secretion.
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Affiliation(s)
- Indu S Ambudkar
- Secretory Physiology Section, Molecular Physiology and Therapeutics Branch, National Institute of Dental Research, National Institutes of Health, Bethesda, MD 20892, United States.
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