1
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Sallinger M, Humer C, Ong HL, Narayanasamy S, Lin QT, Fahrner M, Grabmayr H, Berlansky S, Choi S, Schmidt T, Maltan L, Atzgerstorfer L, Niederwieser M, Frischauf I, Romanin C, Stathopulos PB, Ambudkar I, Leitner R, Bonhenry D, Schindl R. Essential role of N-terminal SAM regions in STIM1 multimerization and function. Proc Natl Acad Sci U S A 2024; 121:e2318874121. [PMID: 38753510 PMCID: PMC11127010 DOI: 10.1073/pnas.2318874121] [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: 11/15/2023] [Accepted: 04/11/2024] [Indexed: 05/18/2024] Open
Abstract
The single-pass transmembrane protein Stromal Interaction Molecule 1 (STIM1), located in the endoplasmic reticulum (ER) membrane, possesses two main functions: It senses the ER-Ca2+ concentration and directly binds to the store-operated Ca2+ channel Orai1 for its activation when Ca2+ recedes. At high resting ER-Ca2+ concentration, the ER-luminal STIM1 domain is kept monomeric but undergoes di/multimerization once stores are depleted. Luminal STIM1 multimerization is essential to unleash the STIM C-terminal binding site for Orai1 channels. However, structural basis of the luminal association sites has so far been elusive. Here, we employed molecular dynamics (MD) simulations and identified two essential di/multimerization segments, the α7 and the adjacent region near the α9-helix in the sterile alpha motif (SAM) domain. Based on MD results, we targeted the two STIM1 SAM domains by engineering point mutations. These mutations interfered with higher-order multimerization of ER-luminal fragments in biochemical assays and puncta formation in live-cell experiments upon Ca2+ store depletion. The STIM1 multimerization impeded mutants significantly reduced Ca2+ entry via Orai1, decreasing the Ca2+ oscillation frequency as well as store-operated Ca2+ entry. Combination of the ER-luminal STIM1 multimerization mutations with gain of function mutations and coexpression of Orai1 partially ameliorated functional defects. Our data point to a hydrophobicity-driven binding within the ER-luminal STIM1 multimer that needs to switch between resting monomeric and activated multimeric state. Altogether, these data reveal that interactions between SAM domains of STIM1 monomers are critical for multimerization and activation of the protein.
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Affiliation(s)
- Matthias Sallinger
- Institute of Biophysics, Johannes Kepler University Linz, Linz4040, Austria
| | - Christina Humer
- Institute of Biophysics, Johannes Kepler University Linz, Linz4040, Austria
| | - Hwei Ling Ong
- Secretory Physiology Section, National Institute of Dental and Craniofacial Research, NIH, Bethesda, MD20892
| | - Sasirekha Narayanasamy
- Secretory Physiology Section, National Institute of Dental and Craniofacial Research, NIH, Bethesda, MD20892
| | - Qi Tong Lin
- Department of Physiology and Pharmacology, Western University, London, ONN6A5C1, Canada
| | - Marc Fahrner
- Institute of Biophysics, Johannes Kepler University Linz, Linz4040, Austria
| | - Herwig Grabmayr
- Institute of Biophysics, Johannes Kepler University Linz, Linz4040, Austria
| | - Sascha Berlansky
- Institute of Biophysics, Johannes Kepler University Linz, Linz4040, Austria
| | - Sean Choi
- Secretory Physiology Section, National Institute of Dental and Craniofacial Research, NIH, Bethesda, MD20892
| | - Tony Schmidt
- Department of Medical Physics and Biophysics, Medical University of Graz, Graz8010, Austria
| | - Lena Maltan
- Institute of Biophysics, Johannes Kepler University Linz, Linz4040, Austria
| | - Lara Atzgerstorfer
- Institute of Biophysics, Johannes Kepler University Linz, Linz4040, Austria
| | - Martin Niederwieser
- Department of Medical Physics and Biophysics, Medical University of Graz, Graz8010, Austria
| | - Irene Frischauf
- Institute of Biophysics, Johannes Kepler University Linz, Linz4040, Austria
| | - Christoph Romanin
- Institute of Biophysics, Johannes Kepler University Linz, Linz4040, Austria
| | - Peter B. Stathopulos
- Department of Physiology and Pharmacology, Western University, London, ONN6A5C1, Canada
| | - Indu Ambudkar
- Secretory Physiology Section, National Institute of Dental and Craniofacial Research, NIH, Bethesda, MD20892
| | - Romana Leitner
- Institute of Biophysics, Johannes Kepler University Linz, Linz4040, Austria
| | - Daniel Bonhenry
- Department of Physics and Materials Science, Faculty of Science, Technology and Medicine, University of Luxembourg, Esch-sur-AlzetteL1511, Luxembourg
| | - Rainer Schindl
- Department of Medical Physics and Biophysics, Medical University of Graz, Graz8010, Austria
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2
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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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3
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Ren R, Li Y. STIM1 in tumor cell death: angel or devil? Cell Death Discov 2023; 9:408. [PMID: 37932320 PMCID: PMC10628139 DOI: 10.1038/s41420-023-01703-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2023] [Revised: 10/21/2023] [Accepted: 10/27/2023] [Indexed: 11/08/2023] Open
Abstract
Stromal interaction molecule 1 (STIM1) is involved in mediating the store-operated Ca2+ entry (SOCE), driving the influx of the intracellular second messenger calcium ion (Ca2+), which is closely associated with tumor cell proliferation, metastasis, apoptosis, autophagy, metabolism and immune processes. STIM1 is not only regulated at the transcriptional level by NF-κB and HIF-1, but also post-transcriptionally modified by miRNAs and degraded by ubiquitination. Recent studies have shown that STIM1 or Ca2+ signaling can regulate apoptosis, autophagy, pyroptosis, and ferroptosis in tumor cells and act discrepantly in different cancers. Furthermore, STIM1 contributes to resistance against antitumor therapy by influencing tumor cell death. Further investigation into the mechanisms through which STIM1 controls other forms of tumor cell death could aid in the discovery of novel therapeutic targets. Moreover, STIM1 has the ability to regulate immune cells within the tumor microenvironment. Here, we review the basic structure, function and regulation of STIM1, summarize the signaling pathways through which STIM1 regulates tumor cell death, and propose the prospects of antitumor therapy by targeting STIM1.
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Affiliation(s)
- Ran Ren
- Chongqing University Cancer Hospital, School of Medicine, Chongqing University, 400044, Chongqing, China
| | - Yongsheng Li
- Chongqing University Cancer Hospital, School of Medicine, Chongqing University, 400044, Chongqing, China.
- Department of Medical Oncology, Chongqing University Cancer Hospital, 400030, Chongqing, China.
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4
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Zhou Y, Jennette MR, Ma G, Kazzaz SA, Baraniak JH, Nwokonko RM, Groff ML, Velasquez-Reynel M, Huang Y, Wang Y, Gill DL. An apical Phe-His pair defines the Orai1-coupling site and its occlusion within STIM1. Nat Commun 2023; 14:6921. [PMID: 37903816 PMCID: PMC10616141 DOI: 10.1038/s41467-023-42254-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2023] [Accepted: 10/04/2023] [Indexed: 11/01/2023] Open
Abstract
Ca2+ signal-generation through inter-membrane junctional coupling between endoplasmic reticulum (ER) STIM proteins and plasma membrane (PM) Orai channels, remains a vital but undefined mechanism. We identify two unusual overlapping Phe-His aromatic pairs within the STIM1 apical helix, one of which (F394-H398) mediates important control over Orai1-STIM1 coupling. In resting STIM1, this locus is deeply clamped within the folded STIM1-CC1 helices, likely near to the ER surface. The clamped environment in holo-STIM1 is critical-positive charge replacing Phe-394 constitutively unclamps STIM1, mimicking store-depletion, negative charge irreversibly locks the clamped-state. In store-activated, unclamped STIM1, Phe-394 mediates binding to the Orai1 channel, but His-398 is indispensable for transducing STIM1-binding into Orai1 channel-gating, and is spatially aligned with Phe-394 in the exposed Sα2 helical apex. Thus, the Phe-His locus traverses between ER and PM surfaces and is decisive in the two critical STIM1 functions-unclamping to activate STIM1, and conformational-coupling to gate the Orai1 channel.
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Affiliation(s)
- Yandong Zhou
- Department of Cellular and Molecular Physiology, The Pennsylvania State University College of Medicine, Hershey, PA, 17033, USA.
| | - Michelle R Jennette
- Department of Cellular and Molecular Physiology, The Pennsylvania State University College of Medicine, Hershey, PA, 17033, USA
| | - Guolin Ma
- Institute of Biosciences and Technology, College of Medicine, Texas A&M University, Houston, TX, 77030, USA
| | - Sarah A Kazzaz
- Department of Cellular and Molecular Physiology, The Pennsylvania State University College of Medicine, Hershey, PA, 17033, USA
| | - James H Baraniak
- Department of Cellular and Molecular Physiology, The Pennsylvania State University College of Medicine, Hershey, PA, 17033, USA
| | - Robert M Nwokonko
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, CA, USA
| | - Mallary L Groff
- Department of Cellular and Molecular Physiology, The Pennsylvania State University College of Medicine, Hershey, PA, 17033, USA
| | - Marcela Velasquez-Reynel
- Department of Cellular and Molecular Physiology, The Pennsylvania State University College of Medicine, Hershey, PA, 17033, USA
| | - Yun Huang
- Center for Epigenetics and Disease Prevention, Institute of Biosciences and Technology, Texas A&M University, Houston, TX, 77030, USA
| | - Youjun Wang
- Beijing Key Laboratory of Gene Resources and Molecular Development, College of Life Sciences, Beijing Normal University, Beijing, 100875, PR China
| | - Donald L Gill
- Department of Cellular and Molecular Physiology, The Pennsylvania State University College of Medicine, Hershey, PA, 17033, USA.
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5
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Horvath F, Berlansky S, Maltan L, Grabmayr H, Fahrner M, Derler I, Romanin C, Renger T, Krobath H. Swing-out opening of stromal interaction molecule 1. Protein Sci 2023; 32:e4571. [PMID: 36691702 PMCID: PMC9929737 DOI: 10.1002/pro.4571] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2022] [Revised: 12/15/2022] [Accepted: 01/13/2023] [Indexed: 01/25/2023]
Abstract
Stromal interaction molecule 1 (STIM1) resides in the endoplasmic reticulum (ER) membrane and senses luminal calcium (Ca2+ ) concentration. STIM1 activation involves a large-scale conformational transition that exposes a STIM1 domain termed "CAD/SOAR", - which is required for activation of the calcium channel Orai. Under resting cell conditions, STIM1 assumes a quiescent state where CAD/SOAR is suspended in an intramolecular clamp formed by the coiled-coil 1 domain (CC1) and CAD/SOAR. Here, we present a structural model of the cytosolic part of the STIM1 resting state using molecular docking simulations that take into account previously reported interaction sites between the CC1α1 and CAD/SOAR domains. We corroborate and refine previously reported interdomain coiled-coil contacts. Based on our model, we provide a detailed analysis of the CC1-CAD/SOAR binding interface using molecular dynamics simulations. We find a very similar binding interface for a proposed domain-swapped configuration of STIM1, where the CAD/SOAR domain of one monomer interacts with the CC1α1 domain of another monomer of STIM1. The rich structural and dynamical information obtained from our simulations reveals novel interaction sites such as M244, I409, or E370, which are crucial for STIM1 quiescent state stability. We tested our predictions by electrophysiological and Förster resonance energy transfer experiments on corresponding single-point mutants. These experiments provide compelling support for the structural model of the STIM1 quiescent state reported here. Based on transitions observed in enhanced-sampling simulations paired with an analysis of the quiescent STIM1 conformational dynamics, our work offers a first atomistic model for CC1α1-CAD/SOAR detachment.
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Affiliation(s)
- Ferdinand Horvath
- Department for Theoretical BiophysicsJohannes Kepler University LinzLinzAustria
| | - Sascha Berlansky
- Institute of BiophysicsJohannes Kepler University LinzLinzAustria
| | - Lena Maltan
- Institute of BiophysicsJohannes Kepler University LinzLinzAustria
| | - Herwig Grabmayr
- Institute of BiophysicsJohannes Kepler University LinzLinzAustria
| | - Marc Fahrner
- Institute of BiophysicsJohannes Kepler University LinzLinzAustria
| | - Isabella Derler
- Institute of BiophysicsJohannes Kepler University LinzLinzAustria
| | | | - Thomas Renger
- Department for Theoretical BiophysicsJohannes Kepler University LinzLinzAustria
| | - Heinrich Krobath
- Department for Theoretical BiophysicsJohannes Kepler University LinzLinzAustria
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6
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Tiffner A, Hopl V, Derler I. CRAC and SK Channels: Their Molecular Mechanisms Associated with Cancer Cell Development. Cancers (Basel) 2022; 15:cancers15010101. [PMID: 36612099 PMCID: PMC9817886 DOI: 10.3390/cancers15010101] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2022] [Revised: 12/16/2022] [Accepted: 12/19/2022] [Indexed: 12/28/2022] Open
Abstract
Cancer represents a major health burden worldwide. Several molecular targets have been discovered alongside treatments with positive clinical outcomes. However, the reoccurrence of cancer due to therapy resistance remains the primary cause of mortality. Endeavors in pinpointing new markers as molecular targets in cancer therapy are highly desired. The significance of the co-regulation of Ca2+-permeating and Ca2+-regulated ion channels in cancer cell development, proliferation, and migration make them promising molecular targets in cancer therapy. In particular, the co-regulation of the Orai1 and SK3 channels has been well-studied in breast and colon cancer cells, where it finally leads to an invasion-metastasis cascade. Nevertheless, many questions remain unanswered, such as which key molecular components determine and regulate their interplay. To provide a solid foundation for a better understanding of this ion channel co-regulation in cancer, we first shed light on the physiological role of Ca2+ and how this ion is linked to carcinogenesis. Then, we highlight the structure/function relationship of Orai1 and SK3, both individually and in concert, their role in the development of different types of cancer, and aspects that are not yet known in this context.
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7
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de la Fuente-Munoz E, Van Den Rym A, García-Solis B, Ochoa Grullón J, Guevara-Hoyer K, Fernández-Arquero M, Galán Dávila L, Matías-Guiú J, Sánchez-Ramón S, Pérez de Diego R. Case Report: Novel STIM1 Gain-of-Function Mutation in a Patient With TAM/STRMK and Immunological Involvement. Front Immunol 2022; 13:917601. [PMID: 35812399 PMCID: PMC9263075 DOI: 10.3389/fimmu.2022.917601] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2022] [Accepted: 05/27/2022] [Indexed: 11/20/2022] Open
Abstract
Gain-of-function (GOF) mutations in STIM1 are responsible for tubular aggregate myopathy and Stormorken syndrome (TAM/STRMK), a clinically overlapping multisystemic disease characterised by muscle weakness, miosis, thrombocytopaenia, hyposplenism, ichthyosis, dyslexia, and short stature. Several mutations have been reported as responsible for the disease. Herein, we describe a patient with TAM/STRMK due to a novel L303P STIM1 mutation, who not only presented clinical manifestations characteristic of TAM/STRMK but also manifested immunological involvement with respiratory infections since childhood, with chronic cough and chronic bronchiectasis. Despite the seemingly normal main immunological parameters, immune cells revealed GOF in calcium signalling compared with healthy donors. The calcium flux dysregulation in the immune cells could be responsible for our patient’s immune involvement. The patient’s mother carried the mutation but did not exhibit TAM/STRMK, manifesting an incomplete penetrance of the mutation. More cases and evidence are necessary to clarify the dual role of STIM1 in immune system dysregulation and myopathy.
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Affiliation(s)
| | - Ana Van Den Rym
- Laboratory of Immunogenetics of Human Diseases, IdiPAZ Institute for Health Research, La Paz University Hospital, Madrid, Spain
- Innate Immunity Group, IdiPAZ Institute for Health Research, La Paz University Hospital, Madrid, Spain
- Interdepartmental Group of Immunodeficiencies, Madrid, Spain
| | - Blanca García-Solis
- Laboratory of Immunogenetics of Human Diseases, IdiPAZ Institute for Health Research, La Paz University Hospital, Madrid, Spain
- Innate Immunity Group, IdiPAZ Institute for Health Research, La Paz University Hospital, Madrid, Spain
- Interdepartmental Group of Immunodeficiencies, Madrid, Spain
| | | | | | - Miguel Fernández-Arquero
- Clinical Immunology Department, San Carlos Clinical Hospital, Madrid, Spain
- Interdepartmental Group of Immunodeficiencies, Madrid, Spain
| | | | | | - Silvia Sánchez-Ramón
- Clinical Immunology Department, San Carlos Clinical Hospital, Madrid, Spain
- Interdepartmental Group of Immunodeficiencies, Madrid, Spain
| | - Rebeca Pérez de Diego
- Laboratory of Immunogenetics of Human Diseases, IdiPAZ Institute for Health Research, La Paz University Hospital, Madrid, Spain
- Innate Immunity Group, IdiPAZ Institute for Health Research, La Paz University Hospital, Madrid, Spain
- Interdepartmental Group of Immunodeficiencies, Madrid, Spain
- *Correspondence: Rebeca Pérez de Diego,
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8
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van Dorp S, Qiu R, Choi UB, Wu MM, Yen M, Kirmiz M, Brunger AT, Lewis RS. Conformational dynamics of auto-inhibition in the ER calcium sensor STIM1. eLife 2021; 10:66194. [PMID: 34730514 PMCID: PMC8651296 DOI: 10.7554/elife.66194] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2021] [Accepted: 10/18/2021] [Indexed: 01/19/2023] Open
Abstract
The dimeric ER Ca2+ sensor STIM1 controls store-operated Ca2+ entry (SOCE) through the regulated binding of its CRAC activation domain (CAD) to Orai channels in the plasma membrane. In resting cells, the STIM1 CC1 domain interacts with CAD to suppress SOCE, but the structural basis of this interaction is unclear. Using single-molecule Förster resonance energy transfer (smFRET) and protein crosslinking approaches, we show that CC1 interacts dynamically with CAD in a domain-swapped configuration with an orientation predicted to sequester its Orai-binding region adjacent to the ER membrane. Following ER Ca2+ depletion and release from CAD, cysteine crosslinking indicates that the two CC1 domains become closely paired along their entire length in the active Orai-bound state. These findings provide a structural basis for the dual roles of CC1: sequestering CAD to suppress SOCE in resting cells and propelling it toward the plasma membrane to activate Orai and SOCE after store depletion.
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Affiliation(s)
- Stijn van Dorp
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, United States
| | - Ruoyi Qiu
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, United States
| | - Ucheor B Choi
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, United States
| | - Minnie M Wu
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, United States
| | - Michelle Yen
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, United States
| | - Michael Kirmiz
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, United States
| | - Axel T Brunger
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, United States.,Howard Hughes Medical Institute, Stanford University School of Medicine, Stanford, United States
| | - Richard S Lewis
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, United States
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9
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Tiffner A, Derler I. Isoform-Specific Properties of Orai Homologues in Activation, Downstream Signaling, Physiology and Pathophysiology. Int J Mol Sci 2021; 22:8020. [PMID: 34360783 PMCID: PMC8347056 DOI: 10.3390/ijms22158020] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Revised: 07/21/2021] [Accepted: 07/23/2021] [Indexed: 11/21/2022] Open
Abstract
Ca2+ ion channels are critical in a variety of physiological events, including cell growth, differentiation, gene transcription and apoptosis. One such essential entry pathway for calcium into the cell is the Ca2+ release-activated Ca2+ (CRAC) channel. It consists of the Ca2+ sensing protein, stromal interaction molecule 1 (STIM1) located in the endoplasmic reticulum (ER) and a Ca2+ ion channel Orai in the plasma membrane. The Orai channel family includes three homologues Orai1, Orai2 and Orai3. While Orai1 is the "classical" Ca2+ ion channel within the CRAC channel complex and plays a universal role in the human body, there is increasing evidence that Orai2 and Orai3 are important in specific physiological and pathophysiological processes. This makes them an attractive target in drug discovery, but requires a detailed understanding of the three Orai channels and, in particular, their differences. Orai channel activation is initiated via Ca2+ store depletion, which is sensed by STIM1 proteins, and induces their conformational change and oligomerization. Upon STIM1 coupling, Orai channels activate to allow Ca2+ permeation into the cell. While this activation mechanism is comparable among the isoforms, they differ by a number of functional and structural properties due to non-conserved regions in their sequences. In this review, we summarize the knowledge as well as open questions in our current understanding of the three isoforms in terms of their structure/function relationship, downstream signaling and physiology as well as pathophysiology.
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Affiliation(s)
| | - Isabella Derler
- Institute of Biophysics, JKU Life Science Center, Johannes Kepler University Linz, A-4020 Linz, Austria;
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10
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Rathner P, Fahrner M, Cerofolini L, Grabmayr H, Horvath F, Krobath H, Gupta A, Ravera E, Fragai M, Bechmann M, Renger T, Luchinat C, Romanin C, Müller N. Interhelical interactions within the STIM1 CC1 domain modulate CRAC channel activation. Nat Chem Biol 2021; 17:196-204. [PMID: 33106661 PMCID: PMC7610458 DOI: 10.1038/s41589-020-00672-8] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2020] [Revised: 09/04/2020] [Accepted: 09/11/2020] [Indexed: 01/28/2023]
Abstract
The calcium release activated calcium channel is activated by the endoplasmic reticulum-resident calcium sensor protein STIM1. On activation, STIM1 C terminus changes from an inactive, tight to an active, extended conformation. A coiled-coil clamp involving the CC1 and CC3 domains is essential in controlling STIM1 activation, with CC1 as the key entity. The nuclear magnetic resonance-derived solution structure of the CC1 domain represents a three-helix bundle stabilized by interhelical contacts, which are absent in the Stormorken disease-related STIM1 R304W mutant. Two interhelical sites between the CC1α1 and CC1α2 helices are key in controlling STIM1 activation, affecting the balance between tight and extended conformations. Nuclear magnetic resonance-directed mutations within these interhelical interactions restore the physiological, store-dependent activation behavior of the gain-of-function STIM1 R304W mutant. This study reveals the functional impact of interhelical interactions within the CC1 domain for modifying the CC1-CC3 clamp strength to control the activation of STIM1.
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Affiliation(s)
- Petr Rathner
- Institute of Organic Chemistry, Johannes Kepler University Linz, Linz, Austria
- Institute of Inorganic Chemistry, Johannes Kepler University Linz, Linz, Austria
| | - Marc Fahrner
- Institute of Biophysics, Johannes Kepler University Linz, Linz, Austria
| | - Linda Cerofolini
- Magnetic Resonance Center (CERM), University of Florence and Consorzio Interuniversitario Risonanze Magnetiche di Metallo Proteine (CIRMMP), Sesto Fiorentino, Italy
| | - Herwig Grabmayr
- Institute of Biophysics, Johannes Kepler University Linz, Linz, Austria
| | - Ferdinand Horvath
- Institute for Theoretical Physics, Johannes Kepler University Linz, Linz, Austria
| | - Heinrich Krobath
- Institute for Theoretical Physics, Johannes Kepler University Linz, Linz, Austria
| | - Agrim Gupta
- Institute of Organic Chemistry, Johannes Kepler University Linz, Linz, Austria
| | - Enrico Ravera
- Magnetic Resonance Center (CERM), University of Florence and Consorzio Interuniversitario Risonanze Magnetiche di Metallo Proteine (CIRMMP), Sesto Fiorentino, Italy
- Department of Chemistry, University of Florence, Sesto Fiorentino, Italy
| | - Marco Fragai
- Magnetic Resonance Center (CERM), University of Florence and Consorzio Interuniversitario Risonanze Magnetiche di Metallo Proteine (CIRMMP), Sesto Fiorentino, Italy
- Department of Chemistry, University of Florence, Sesto Fiorentino, Italy
| | - Matthias Bechmann
- Institute of Organic Chemistry, Johannes Kepler University Linz, Linz, Austria
| | - Thomas Renger
- Institute for Theoretical Physics, Johannes Kepler University Linz, Linz, Austria
| | - Claudio Luchinat
- Magnetic Resonance Center (CERM), University of Florence and Consorzio Interuniversitario Risonanze Magnetiche di Metallo Proteine (CIRMMP), Sesto Fiorentino, Italy
- Department of Chemistry, University of Florence, Sesto Fiorentino, Italy
| | - Christoph Romanin
- Institute of Biophysics, Johannes Kepler University Linz, Linz, Austria.
| | - Norbert Müller
- Institute of Organic Chemistry, Johannes Kepler University Linz, Linz, Austria.
- Faculty of Science, University of South Bohemia, České Budějovice, Czech Republic.
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11
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Grabmayr H, Romanin C, Fahrner M. STIM Proteins: An Ever-Expanding Family. Int J Mol Sci 2020; 22:E378. [PMID: 33396497 PMCID: PMC7795233 DOI: 10.3390/ijms22010378] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2020] [Revised: 12/20/2020] [Accepted: 12/26/2020] [Indexed: 02/06/2023] Open
Abstract
Stromal interaction molecules (STIM) are a distinct class of ubiquitously expressed single-pass transmembrane proteins in the endoplasmic reticulum (ER) membrane. Together with Orai ion channels in the plasma membrane (PM), they form the molecular basis of the calcium release-activated calcium (CRAC) channel. An intracellular signaling pathway known as store-operated calcium entry (SOCE) is critically dependent on the CRAC channel. The SOCE pathway is activated by the ligand-induced depletion of the ER calcium store. STIM proteins, acting as calcium sensors, subsequently sense this depletion and activate Orai ion channels via direct physical interaction to allow the influx of calcium ions for store refilling and downstream signaling processes. This review article is dedicated to the latest advances in the field of STIM proteins. New results of ongoing investigations based on the recently published functional data as well as structural data from nuclear magnetic resonance (NMR) spectroscopy and molecular dynamics (MD) simulations are reported and complemented with a discussion of the latest developments in the research of STIM protein isoforms and their differential functions in regulating SOCE.
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Affiliation(s)
| | - Christoph Romanin
- Institute of Biophysics, Johannes Kepler University Linz, Gruberstrasse 40, 4020 Linz, Austria;
| | - Marc Fahrner
- Institute of Biophysics, Johannes Kepler University Linz, Gruberstrasse 40, 4020 Linz, Austria;
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12
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Tiffner A, Derler I. Molecular Choreography and Structure of Ca 2+ Release-Activated Ca 2+ (CRAC) and K Ca2+ Channels and Their Relevance in Disease with Special Focus on Cancer. MEMBRANES 2020; 10:E425. [PMID: 33333945 PMCID: PMC7765462 DOI: 10.3390/membranes10120425] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/04/2020] [Revised: 12/04/2020] [Accepted: 12/07/2020] [Indexed: 12/16/2022]
Abstract
Ca2+ ions play a variety of roles in the human body as well as within a single cell. Cellular Ca2+ signal transduction processes are governed by Ca2+ sensing and Ca2+ transporting proteins. In this review, we discuss the Ca2+ and the Ca2+-sensing ion channels with particular focus on the structure-function relationship of the Ca2+ release-activated Ca2+ (CRAC) ion channel, the Ca2+-activated K+ (KCa2+) ion channels, and their modulation via other cellular components. Moreover, we highlight their roles in healthy signaling processes as well as in disease with a special focus on cancer. As KCa2+ channels are activated via elevations of intracellular Ca2+ levels, we summarize the current knowledge on the action mechanisms of the interplay of CRAC and KCa2+ ion channels and their role in cancer cell development.
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Affiliation(s)
| | - Isabella Derler
- Institute of Biophysics, JKU Life Science Center, Johannes Kepler University Linz, A-4020 Linz, Austria;
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13
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Gibhardt CS, Cappello S, Bhardwaj R, Schober R, Kirsch SA, Bonilla Del Rio Z, Gahbauer S, Bochicchio A, Sumanska M, Ickes C, Stejerean-Todoran I, Mitkovski M, Alansary D, Zhang X, Revazian A, Fahrner M, Lunz V, Frischauf I, Luo T, Ezerina D, Messens J, Belousov VV, Hoth M, Böckmann RA, Hediger MA, Schindl R, Bogeski I. Oxidative Stress-Induced STIM2 Cysteine Modifications Suppress Store-Operated Calcium Entry. Cell Rep 2020; 33:108292. [PMID: 33086068 DOI: 10.1016/j.celrep.2020.108292] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2020] [Revised: 08/28/2020] [Accepted: 09/29/2020] [Indexed: 12/12/2022] Open
Abstract
Store-operated calcium entry (SOCE) through STIM-gated ORAI channels governs vital cellular functions. In this context, SOCE controls cellular redox signaling and is itself regulated by redox modifications. However, the molecular mechanisms underlying this calcium-redox interplay and the functional outcomes are not fully understood. Here, we examine the role of STIM2 in SOCE redox regulation. Redox proteomics identify cysteine 313 as the main redox sensor of STIM2 in vitro and in vivo. Oxidative stress suppresses SOCE and calcium currents in cells overexpressing STIM2 and ORAI1, an effect that is abolished by mutation of cysteine 313. FLIM and FRET microscopy, together with MD simulations, indicate that oxidative modifications of cysteine 313 alter STIM2 activation dynamics and thereby hinder STIM2-mediated gating of ORAI1. In summary, this study establishes STIM2-controlled redox regulation of SOCE as a mechanism that affects several calcium-regulated physiological processes, as well as stress-induced pathologies.
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Affiliation(s)
- Christine Silvia Gibhardt
- Molecular Physiology, Institute of Cardiovascular Physiology, University Medical Center, Georg-August-University, Göttingen, Germany
| | - Sabrina Cappello
- Molecular Physiology, Institute of Cardiovascular Physiology, University Medical Center, Georg-August-University, Göttingen, Germany
| | - Rajesh Bhardwaj
- Department of Nephrology and Hypertension, Inselspital, University of Bern, Bern, Switzerland
| | - Romana Schober
- Institute of Biophysics, JKU Life Science Center, Johannes Kepler University Linz, Linz, Austria; Gottfried Schatz Research Center, Medical University of Graz, Graz, Austria
| | - Sonja Agnes Kirsch
- Computational Biology, Department of Biology, Friedrich-Alexander University of Erlangen-Nürnberg, Germany
| | - Zuriñe Bonilla Del Rio
- Molecular Physiology, Institute of Cardiovascular Physiology, University Medical Center, Georg-August-University, Göttingen, Germany
| | - Stefan Gahbauer
- Computational Biology, Department of Biology, Friedrich-Alexander University of Erlangen-Nürnberg, Germany
| | - Anna Bochicchio
- Computational Biology, Department of Biology, Friedrich-Alexander University of Erlangen-Nürnberg, Germany
| | - Magdalena Sumanska
- Molecular Physiology, Institute of Cardiovascular Physiology, University Medical Center, Georg-August-University, Göttingen, Germany
| | - Christian Ickes
- Molecular Physiology, Institute of Cardiovascular Physiology, University Medical Center, Georg-August-University, Göttingen, Germany
| | - Ioana Stejerean-Todoran
- Molecular Physiology, Institute of Cardiovascular Physiology, University Medical Center, Georg-August-University, Göttingen, Germany
| | - Miso Mitkovski
- Light Microscopy Facility, Max Planck Institute of Experimental Medicine, Göttingen, Germany
| | - Dalia Alansary
- Biophysics, Center for Integrative Physiology and Molecular Medicine, Saarland University, Homburg, Germany
| | - Xin Zhang
- Molecular Physiology, Institute of Cardiovascular Physiology, University Medical Center, Georg-August-University, Göttingen, Germany
| | - Aram Revazian
- Molecular Physiology, Institute of Cardiovascular Physiology, University Medical Center, Georg-August-University, Göttingen, Germany
| | - Marc Fahrner
- Institute of Biophysics, JKU Life Science Center, Johannes Kepler University Linz, Linz, Austria
| | - Victoria Lunz
- Institute of Biophysics, JKU Life Science Center, Johannes Kepler University Linz, Linz, Austria
| | - Irene Frischauf
- Institute of Biophysics, JKU Life Science Center, Johannes Kepler University Linz, Linz, Austria
| | - Ting Luo
- VIB-VUB Center for Structural Biology, Brussels Center for Redox Biology, Structural Biology Brussels, Vrije Universiteit Brussel, Brussels, Belgium
| | - Daria Ezerina
- VIB-VUB Center for Structural Biology, Brussels Center for Redox Biology, Structural Biology Brussels, Vrije Universiteit Brussel, Brussels, Belgium
| | - Joris Messens
- VIB-VUB Center for Structural Biology, Brussels Center for Redox Biology, Structural Biology Brussels, Vrije Universiteit Brussel, Brussels, Belgium
| | - Vsevolod Vadimovich Belousov
- Molecular Physiology, Institute of Cardiovascular Physiology, University Medical Center, Georg-August-University, Göttingen, Germany; Pirogov Russian National Research Medical University, Moscow, Russia; Federal Center of Brain Research and Neurotechnologies of the Federal Medical Biological Agency, Moscow, Russia
| | - Markus Hoth
- Biophysics, Center for Integrative Physiology and Molecular Medicine, Saarland University, Homburg, Germany
| | - Rainer Arnold Böckmann
- Computational Biology, Department of Biology, Friedrich-Alexander University of Erlangen-Nürnberg, Germany
| | | | - Rainer Schindl
- Gottfried Schatz Research Center, Medical University of Graz, Graz, Austria.
| | - Ivan Bogeski
- Molecular Physiology, Institute of Cardiovascular Physiology, University Medical Center, Georg-August-University, Göttingen, Germany.
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14
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Abstract
Store-operated calcium entry (SOCE) through Orai ion channels is an intracellular signaling pathway that is initiated by ligand-induced depletion of calcium from the endoplasmic reticulum (ER) store. The molecular link between SOCE and ER store depletion is thereby provided by a distinct class of single pass ER transmembrane proteins known as stromal interaction molecules (STIM). STIM proteins are equipped with a precise N-terminal calcium sensing domain that enables them to react to changes of the ER luminal calcium concentration. Additionally, a C-terminal coiled-coil domain permits relaying of signals to Orai ion channels via direct physical interaction. In this review, we provide a brief introduction to STIM proteins with a focus on structure and function and give an overview of recent developments in the field of STIM research.
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Affiliation(s)
- Marc Fahrner
- Institute of Biophysics, Johannes Kepler University Linz, Gruberstrasse 40, 4020 Linz, Austria
| | - Herwig Grabmayr
- Institute of Biophysics, Johannes Kepler University Linz, Gruberstrasse 40, 4020 Linz, Austria
| | - Christoph Romanin
- Institute of Biophysics, Johannes Kepler University Linz, Gruberstrasse 40, 4020 Linz, Austria
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15
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Noble M, Lin QT, Sirko C, Houpt JA, Novello MJ, Stathopulos PB. Structural Mechanisms of Store-Operated and Mitochondrial Calcium Regulation: Initiation Points for Drug Discovery. Int J Mol Sci 2020; 21:E3642. [PMID: 32455637 PMCID: PMC7279490 DOI: 10.3390/ijms21103642] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2020] [Revised: 05/11/2020] [Accepted: 05/17/2020] [Indexed: 12/18/2022] Open
Abstract
Calcium (Ca2+) is a universal signaling ion that is essential for the life and death processes of all eukaryotes. In humans, numerous cell stimulation pathways lead to the mobilization of sarco/endoplasmic reticulum (S/ER) stored Ca2+, resulting in the propagation of Ca2+ signals through the activation of processes, such as store-operated Ca2+ entry (SOCE). SOCE provides a sustained Ca2+ entry into the cytosol; moreover, the uptake of SOCE-mediated Ca2+ by mitochondria can shape cytosolic Ca2+ signals, function as a feedback signal for the SOCE molecular machinery, and drive numerous mitochondrial processes, including adenosine triphosphate (ATP) production and distinct cell death pathways. In recent years, tremendous progress has been made in identifying the proteins mediating these signaling pathways and elucidating molecular structures, invaluable for understanding the underlying mechanisms of function. Nevertheless, there remains a disconnect between using this accumulating protein structural knowledge and the design of new research tools and therapies. In this review, we provide an overview of the Ca2+ signaling pathways that are involved in mediating S/ER stored Ca2+ release, SOCE, and mitochondrial Ca2+ uptake, as well as pinpoint multiple levels of crosstalk between these pathways. Further, we highlight the significant protein structures elucidated in recent years controlling these Ca2+ signaling pathways. Finally, we describe a simple strategy that aimed at applying the protein structural data to initiating drug design.
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Affiliation(s)
- Megan Noble
- Department of Physiology and Pharmacology, Schulich School of Medicine and Dentistry, The University of Western Ontario, London, ON N6A5C1, Canada; (M.N.); (Q.-T.L.); (C.S.); (M.J.N.)
| | - Qi-Tong Lin
- Department of Physiology and Pharmacology, Schulich School of Medicine and Dentistry, The University of Western Ontario, London, ON N6A5C1, Canada; (M.N.); (Q.-T.L.); (C.S.); (M.J.N.)
| | - Christian Sirko
- Department of Physiology and Pharmacology, Schulich School of Medicine and Dentistry, The University of Western Ontario, London, ON N6A5C1, Canada; (M.N.); (Q.-T.L.); (C.S.); (M.J.N.)
| | - Jacob A. Houpt
- Department of Medicine, Schulich School of Medicine and Dentistry, The University of Western Ontario, London, ON N6A5C1, Canada;
| | - Matthew J. Novello
- Department of Physiology and Pharmacology, Schulich School of Medicine and Dentistry, The University of Western Ontario, London, ON N6A5C1, Canada; (M.N.); (Q.-T.L.); (C.S.); (M.J.N.)
| | - Peter B. Stathopulos
- Department of Physiology and Pharmacology, Schulich School of Medicine and Dentistry, The University of Western Ontario, London, ON N6A5C1, Canada; (M.N.); (Q.-T.L.); (C.S.); (M.J.N.)
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16
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Lee SK, Lee MH, Jeong SJ, Qin X, Lee AR, Park H, Park CY. The inactivation domain of STIM1 acts through intramolecular binding to the coiled-coil domain in the resting state. J Cell Sci 2020; 133:jcs.237354. [PMID: 31831524 DOI: 10.1242/jcs.237354] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2019] [Accepted: 12/05/2019] [Indexed: 01/15/2023] Open
Abstract
Store-operated Ca2+ entry (SOCE) is a major Ca2+ influx pathway that is controlled by the ER Ca2+ sensor STIM1. Abnormal activation of STIM1 directly influences Ca2+ influx, resulting in severe diseases such as Stormorken syndrome. The inactivation domain of STIM1 (IDstim) has been identified as being essential for Ca2+-dependent inactivation of STIM1 (CDI) after SOCE occurs. However, it is unknown whether IDstim is involved in keeping STIM1 inactive before CDI. Herein, we show that IDstim helps STIM1 keep inactive through intramolecular binding with the coiled-coil domain. Between IDstim and the coiled-coil domain, we found a short conserved linker whose extension or mutation leads to the constitutive activation of STIM1. We have demonstrated that IDstim needs the coiled-coil domain 1 (CC1) to inhibit the Ca2+ release-activated Ca2+ (CRAC) activation domain (CAD) activity and binds to a CC1-CAD fragment. Serial deletion of CC1 revealed that CC1α1 is a co-inhibitory domain of IDstim. CC1α1 deletion or leucine mutation, which abolishes the closed conformation, impaired the inhibitory effect and binding of IDstim. These results suggest that IDstim cooperates with CC1α1 to help STIM1 keep inactive under resting conditions.
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Affiliation(s)
- Sang Kwon Lee
- Department of Biological Sciences, School of Life Sciences, Ulsan National Institute of Science and Technology, 44919 Ulsan, Republic of Korea
| | - Min-Hsun Lee
- Department of Physics, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong
| | - Su Ji Jeong
- Department of Biological Sciences, School of Life Sciences, Ulsan National Institute of Science and Technology, 44919 Ulsan, Republic of Korea
| | - Xianan Qin
- Department of Physics, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong
| | - Ah Reum Lee
- Department of Biological Sciences, School of Life Sciences, Ulsan National Institute of Science and Technology, 44919 Ulsan, Republic of Korea
| | - Hyokeun Park
- Department of Physics, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong .,Division of Life Science, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong.,State Key Laboratory of Molecular Neuroscience, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong
| | - Chan Young Park
- Department of Biological Sciences, School of Life Sciences, Ulsan National Institute of Science and Technology, 44919 Ulsan, Republic of Korea
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17
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Bhuvaneshwari S, Sankaranarayanan K. Structural and Mechanistic Insights of CRAC Channel as a Drug Target in Autoimmune Disorder. Curr Drug Targets 2019; 21:55-75. [PMID: 31556856 DOI: 10.2174/1389450120666190926150258] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2019] [Revised: 08/20/2019] [Accepted: 08/20/2019] [Indexed: 01/17/2023]
Abstract
BACKGROUND Calcium (Ca2+) ion is a major intracellular signaling messenger, controlling a diverse array of cellular functions like gene expression, secretion, cell growth, proliferation, and apoptosis. The major mechanism controlling this Ca2+ homeostasis is store-operated Ca2+ release-activated Ca2+ (CRAC) channels. CRAC channels are integral membrane protein majorly constituted via two proteins, the stromal interaction molecule (STIM) and ORAI. Following Ca2+ depletion in the Endoplasmic reticulum (ER) store, STIM1 interacts with ORAI1 and leads to the opening of the CRAC channel gate and consequently allows the influx of Ca2+ ions. A plethora of studies report that aberrant CRAC channel activity due to Loss- or gain-of-function mutations in ORAI1 and STIM1 disturbs this Ca2+ homeostasis and causes several autoimmune disorders. Hence, it clearly indicates that the therapeutic target of CRAC channels provides the space for a new approach to treat autoimmune disorders. OBJECTIVE This review aims to provide the key structural and mechanical insights of STIM1, ORAI1 and other molecular modulators involved in CRAC channel regulation. RESULTS AND CONCLUSION Understanding the structure and function of the protein is the foremost step towards improving the effective target specificity by limiting their potential side effects. Herein, the review mainly focusses on the structural underpinnings of the CRAC channel gating mechanism along with its biophysical properties that would provide the solid foundation to aid the development of novel targeted drugs for an autoimmune disorder. Finally, the immune deficiencies caused due to mutations in CRAC channel and currently used pharmacological blockers with their limitation are briefly summarized.
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Affiliation(s)
- Sampath Bhuvaneshwari
- Ion Channel Biology Laboratory, AU-KBC Research Centre, Madras Institute of Technology, Anna University, Chrompet, Chennai -600 044, India
| | - Kavitha Sankaranarayanan
- Ion Channel Biology Laboratory, AU-KBC Research Centre, Madras Institute of Technology, Anna University, Chrompet, Chennai -600 044, India
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18
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Hirve N, Rajanikanth V, Hogan PG, Gudlur A. Coiled-Coil Formation Conveys a STIM1 Signal from ER Lumen to Cytoplasm. Cell Rep 2019; 22:72-83. [PMID: 29298434 DOI: 10.1016/j.celrep.2017.12.030] [Citation(s) in RCA: 59] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2017] [Revised: 11/07/2017] [Accepted: 12/10/2017] [Indexed: 10/18/2022] Open
Abstract
STIM1 and STIM2 are endoplasmic reticulum (ER) membrane proteins that sense decreases in ER-luminal free Ca2+ and, through a conformational change in the STIM cytoplasmic domain, control gating of the plasma membrane Ca2+ channel ORAI1. To determine how STIM1 conveys a signal from the ER lumen to the cytoplasm, we studied the Ca2+-dependent conformational change of engineered STIM1 proteins in isolated ER membranes and, in parallel, physiological activation of these proteins in cells. We find that conserved "sentinel" features of the CC1 region help to prevent activation while Ca2+ is bound to STIM ER-luminal domains. Reduced ER-luminal Ca2+ drives a concerted conformational change, in which STIM luminal domains rearrange and the STIM transmembrane helices and initial parts of the CC1 regions pair in an extended coiled coil. This intradimer rearrangement overcomes the relatively weak CC1-SOAR/CAD interactions that hold STIM in an inactive conformation, releasing the SOAR/CAD domain to activate ORAI channels.
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Affiliation(s)
- Nupura Hirve
- Division of Signaling and Gene Expression, La Jolla Institute for Allergy and Immunology, La Jolla, CA 92037, USA
| | - Vangipurapu Rajanikanth
- Division of Signaling and Gene Expression, La Jolla Institute for Allergy and Immunology, La Jolla, CA 92037, USA
| | - Patrick G Hogan
- Division of Signaling and Gene Expression, La Jolla Institute for Allergy and Immunology, La Jolla, CA 92037, USA; Program in Immunology, University of California, San Diego, La Jolla, CA 92037, USA.
| | - Aparna Gudlur
- Division of Signaling and Gene Expression, La Jolla Institute for Allergy and Immunology, La Jolla, CA 92037, USA
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19
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Bonhenry D, Schober R, Schmidt T, Waldherr L, Ettrich RH, Schindl R. Mechanistic insights into the Orai channel by molecular dynamics simulations. Semin Cell Dev Biol 2019; 94:50-58. [PMID: 30639326 DOI: 10.1016/j.semcdb.2019.01.002] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2018] [Revised: 12/12/2018] [Accepted: 01/05/2019] [Indexed: 10/27/2022]
Abstract
Highly Ca2+ selective channels trigger a large variety of cellular signaling processes in both excitable and non-excitable cells. Among these channels, the Orai channel is unique in its activation mechanism and its structure. It mediates Ca2+ influx into the cytosol with an extremely small unitary conductance over longer time-scales, ranging from minutes up to several hours. Its activation is regulated by the Ca2+ content of the endoplasmic reticulum (ER). Depletion of luminal [Ca2+]ER is sensed by the STIM1 single transmembrane protein that directly binds and gates the Orai1 channel. Orai mediated Ca2+ influx increases cytosolic Ca2+ from 100 nM up to low micromolar range close to the pore and thereby forms Ca2+ microdomains. Hence, these features of the Orai channel can trigger long-term signaling processes without affecting the overall Ca2+ content of a single living cell. Here we focus on the architecture and dynamic conformational changes within the Orai channel. This review summarizes current achievements of molecular dynamics simulations in combination with live cell recordings to address gating and permeation of the Orai channel with molecular precision.
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Affiliation(s)
- Daniel Bonhenry
- Center for Nanobiology and Structural Biology, Institute of Microbiology, Academy of Sciences of the Czech Republic, Nové Hrady CZ-373 33, Czech Republic.
| | - Romana Schober
- Institute for Biophysics, Johannes Kepler University Linz, A-4040 Linz, Austria
| | - Tony Schmidt
- Gottfried Schatz Research Center, Medical University of Graz, A-8010 Graz, Austria
| | - Linda Waldherr
- Gottfried Schatz Research Center, Medical University of Graz, A-8010 Graz, Austria
| | - Rüdiger H Ettrich
- Center for Nanobiology and Structural Biology, Institute of Microbiology, Academy of Sciences of the Czech Republic, Nové Hrady CZ-373 33, Czech Republic; College of Biomedical Sciences, Larkin University, Miami, FL 33169, United States
| | - Rainer Schindl
- Gottfried Schatz Research Center, Medical University of Graz, A-8010 Graz, Austria.
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20
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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: 67] [Impact Index Per Article: 13.4] [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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21
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Schober R, Waldherr L, Schmidt T, Graziani A, Stilianu C, Legat L, Groschner K, Schindl R. STIM1 and Orai1 regulate Ca 2+ microdomains for activation of transcription. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2018; 1866:1079-1091. [PMID: 30408546 DOI: 10.1016/j.bbamcr.2018.11.001] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/30/2018] [Revised: 10/31/2018] [Accepted: 11/01/2018] [Indexed: 02/07/2023]
Abstract
Since calcium (Ca2+) regulates a large variety of cellular signaling processes in a cell's life, precise control of Ca2+ concentrations within the cell is essential. This enables the transduction of information via Ca2+ changes in a time-dependent and spatially defined manner. Here, we review molecular and functional aspects of how the store-operated Ca2+ channel Orai1 creates spatiotemporal Ca2+ microdomains. The architecture of this channel is unique, with a long helical pore and a six-fold symmetry. Energetic barriers within the Ca2+ channel pathway limit permeation to allow an extensive local Ca2+ increase in close proximity to the channel. The precise timing of the Orai1 channel function is controlled by direct binding to STIM proteins upon Ca2+ depletion in the endoplasmic reticulum. These induced Ca2+ microdomains are tailored to, and sufficient for, triggering long-term activation processes, such as transcription factor activation and subsequent gene regulation. We describe the principles of spatiotemporal activation of the transcription factor NFAT and compare its signaling characteristics to those of the autophagy regulating transcription factors, MITF and TFEB.
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Affiliation(s)
- Romana Schober
- Institute for Biophysics, Johannes Kepler University Linz, A-4040 Linz, Austria.
| | - Linda Waldherr
- Gottfried Schatz Research Center, Medical University of Graz, A-8010 Graz, Austria
| | - Tony Schmidt
- Gottfried Schatz Research Center, Medical University of Graz, A-8010 Graz, Austria
| | - Annarita Graziani
- Gottfried Schatz Research Center, Medical University of Graz, A-8010 Graz, Austria
| | - Clemens Stilianu
- Gottfried Schatz Research Center, Medical University of Graz, A-8010 Graz, Austria
| | - Lorenz Legat
- Gottfried Schatz Research Center, Medical University of Graz, A-8010 Graz, Austria
| | - Klaus Groschner
- Gottfried Schatz Research Center, Medical University of Graz, A-8010 Graz, Austria
| | - Rainer Schindl
- Gottfried Schatz Research Center, Medical University of Graz, A-8010 Graz, Austria.
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22
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The 2β Splice Variation Alters the Structure and Function of the Stromal Interaction Molecule Coiled-Coil Domains. Int J Mol Sci 2018; 19:ijms19113316. [PMID: 30366379 PMCID: PMC6274866 DOI: 10.3390/ijms19113316] [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: 10/06/2018] [Revised: 10/21/2018] [Accepted: 10/22/2018] [Indexed: 12/16/2022] Open
Abstract
Stromal interaction molecule (STIM)-1 and -2 regulate agonist-induced and basal cytosolic calcium (Ca2+) levels after oligomerization and translocation to endoplasmic reticulum (ER)-plasma membrane (PM) junctions. At these junctions, the STIM cytosolic coiled-coil (CC) domains couple to PM Orai1 proteins and gate these Ca2+ release-activated Ca2+ (CRAC) channels, which facilitate store-operated Ca2+ entry (SOCE). Unlike STIM1 and STIM2, which are SOCE activators, the STIM2β splice variant contains an 8-residue insert located within the conserved CCs which inhibits SOCE. It remains unclear if the 2β insert further depotentiates weak STIM2 coupling to Orai1 or independently causes structural perturbations which prevent SOCE. Here, we use far-UV circular dichroism, light scattering, exposed hydrophobicity analysis, solution small angle X-ray scattering, and a chimeric STIM1/STIM2β functional assessment to provide insights into the molecular mechanism by which the 2β insert precludes SOCE activation. We find that the 2β insert reduces the overall α-helicity and enhances the exposed hydrophobicity of the STIM2 CC domains in the absence of a global conformational change. Remarkably, incorporation of the 2β insert into the STIM1 context not only affects the secondary structure and hydrophobicity as observed for STIM2, but also eliminates the more robust SOCE response mediated by STIM1. Collectively, our data show that the 2β insert directly precludes Orai1 channel activation by inducing structural perturbations in the STIM CC region.
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Cho CH, Lee KJ, Lee EH. With the greatest care, stromal interaction molecule (STIM) proteins verify what skeletal muscle is doing. BMB Rep 2018; 51:378-387. [PMID: 29898810 PMCID: PMC6130827 DOI: 10.5483/bmbrep.2018.51.8.128] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2018] [Indexed: 12/11/2022] Open
Abstract
Skeletal muscle contracts or relaxes to maintain the body position and locomotion. For the contraction and relaxation of skeletal muscle, Ca2+ in the cytosol of skeletal muscle fibers acts as a switch to turn on and off a series of contractile proteins. The cytosolic Ca2+ level in skeletal muscle fibers is governed mainly by movements of Ca2+ between the cytosol and the sarcoplasmic reticulum (SR). Store-operated Ca2+ entry (SOCE), a Ca2+ entryway from the extracellular space to the cytosol, has gained a significant amount of attention from muscle physiologists. Orai1 and stromal interaction molecule 1 (STIM1) are the main protein identities of SOCE. This mini-review focuses on the roles of STIM proteins and SOCE in the physiological and pathophysiological functions of skeletal muscle and in their correlations with recently identified proteins, as well as historical proteins that are known to mediate skeletal muscle function.
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Affiliation(s)
- Chung-Hyun Cho
- Department of Pharmacology, College of Medicine, Seoul National University, Seoul 08826, Korea
| | - Keon Jin Lee
- Department of Physiology, College of Medicine, The Catholic University of Korea; Department of Biomedicine & Health Sciences, Graduate School, The Catholic University of Korea, Seoul 06591, Korea
| | - Eun Hui Lee
- Department of Physiology, College of Medicine, The Catholic University of Korea; Department of Biomedicine & Health Sciences, Graduate School, The Catholic University of Korea, Seoul 06591, Korea
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Nguyen NT, Han W, Cao W, Wang Y, Wen S, Huang Y, Li M, Du L, Zhou Y. Store‐Operated Calcium Entry Mediated by ORAI and STIM. Compr Physiol 2018; 8:981-1002. [DOI: 10.1002/cphy.c170031] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
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Rathner P, Stadlbauer M, Romanin C, Fahrner M, Derler I, Müller N. Rapid NMR-scale purification of 15N, 13C isotope-labeled recombinant human STIM1 coiled coil fragments. Protein Expr Purif 2018; 146:45-50. [PMID: 29414068 DOI: 10.1016/j.pep.2018.01.013] [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] [Received: 09/10/2017] [Revised: 01/05/2018] [Accepted: 01/24/2018] [Indexed: 10/17/2022]
Abstract
We report a new NMR-scale purification procedure for two recombinant wild type fragments of the stromal interaction molecule 1 (STIM1). This protein acts as a calcium sensor in the endoplasmic reticulum (ER) and extends into the cytosol accumulating at ER - plasma membrane (PM) junctions upon calcium store depletion ultimately leading to activation of the Orai/CRAC channel. The functionally relevant cytosolic part of STIM1 consists of three coiled coil domains, which are mainly involved in intra- and inter-molecular homomeric interactions as well as coupling to and gating of CRAC channels. The optimized one-step rapid purification procedure for two 15N,13C isotope-labeled cytosolic coiled coil fragments, which avoids the problems of previous approaches. The high yields of soluble well folded 15N,13C isotope-labeled cytosolic coiled coil fragments followed by detergent screening provide for initial NMR characterization of these domains. The longer 30.5 kDa fragment represents the largest STIM1 wild type fragment that has been recombinantly prepared and characterized in solution without need for mutation or refolding.
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Affiliation(s)
- Petr Rathner
- Institute of Organic Chemistry, Johannes Kepler University Linz, Altenbergerstraße 69, 4040 Linz, Austria
| | - Michael Stadlbauer
- Institute of Biophysics, Johannes Kepler University Linz, Gruberstraße 40, 4020 Linz, Austria
| | - Christoph Romanin
- Institute of Biophysics, Johannes Kepler University Linz, Gruberstraße 40, 4020 Linz, Austria
| | - Marc Fahrner
- Institute of Biophysics, Johannes Kepler University Linz, Gruberstraße 40, 4020 Linz, Austria
| | - Isabella Derler
- Institute of Biophysics, Johannes Kepler University Linz, Gruberstraße 40, 4020 Linz, Austria
| | - Norbert Müller
- Institute of Organic Chemistry, Johannes Kepler University Linz, Altenbergerstraße 69, 4040 Linz, Austria; Faculty of Science, University of South Bohemia, Branišovská 31, 370 05 České Budějovice, Czech Republic.
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Novello MJ, Zhu J, Feng Q, Ikura M, Stathopulos PB. Structural elements of stromal interaction molecule function. Cell Calcium 2018; 73:88-94. [PMID: 29698850 DOI: 10.1016/j.ceca.2018.04.006] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2018] [Accepted: 04/13/2018] [Indexed: 02/02/2023]
Abstract
Stromal interaction molecule (STIM)-1 and -2 are multi-domain, single-pass transmembrane proteins involved in sensing changes in compartmentalized calcium (Ca2+) levels and transducing this cellular signal to Orai1 channel proteins. Our understanding of the molecular mechanisms underlying STIM signaling has been dramatically improved through available X-ray crystal and solution NMR structures. This high-resolution structural data has revealed that intricate intramolecular and intermolecular protein-protein interactions are involved in converting STIMs from the quiescent to activation-competent states. This review article summarizes the current high resolution structural data on specific EF-hand, sterile α motif and coiled-coil interactions which drive STIM function in the activation of Orai1 channels. Further, the work discusses the effects of post-translational modifications on the structure and function of STIMs. Future structural studies on larger STIM:Orai complexes will be critical to fully defining the molecular bases for STIM function and how post-translational modifications influence these mechanisms.
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Affiliation(s)
- Matthew J Novello
- Department of Physiology and Pharmacology, University of Western Ontario, London, Ontario, Canada
| | - Jinhui Zhu
- Department of Physiology and Pharmacology, University of Western Ontario, London, Ontario, Canada
| | - Qingping Feng
- Department of Physiology and Pharmacology, University of Western Ontario, London, Ontario, Canada
| | - Mitsuhiko Ikura
- Princess Margaret Cancer Center, University Health Network, Toronto, Ontario, Canada.
| | - Peter B Stathopulos
- Department of Physiology and Pharmacology, University of Western Ontario, London, Ontario, Canada.
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Fahrner M, Stadlbauer M, Muik M, Rathner P, Stathopulos P, Ikura M, Müller N, Romanin C. A dual mechanism promotes switching of the Stormorken STIM1 R304W mutant into the activated state. Nat Commun 2018; 9:825. [PMID: 29483506 PMCID: PMC5827659 DOI: 10.1038/s41467-018-03062-w] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2017] [Accepted: 01/17/2018] [Indexed: 11/22/2022] Open
Abstract
STIM1 and Orai1 are key components of the Ca2+-release activated Ca2+ (CRAC) current. Orai1, which represents the subunit forming the CRAC channel complex, is activated by the ER resident Ca2+ sensor STIM1. The genetically inherited Stormorken syndrome disease has been associated with the STIM1 single point R304W mutant. The resulting constitutive activation of Orai1 mainly involves the CRAC-activating domain CAD/SOAR of STIM1, the exposure of which is regulated by the molecular interplay between three cytosolic STIM1 coiled-coil (CC) domains. Here we present a dual mechanism by which STIM1 R304W attains the pathophysiological, constitutive activity eliciting the Stormorken syndrome. The R304W mutation induces a helical elongation within the CC1 domain, which together with an increased CC1 homomerization, destabilize the resting state of STIM1. This culminates, even in the absence of store depletion, in structural extension and CAD/SOAR exposure of STIM1 R304W leading to constitutive CRAC channel activation and Stormorken disease. Stormorken syndrome is associated with the R304W mutation in STIM1, which is a Calcium sensor in the endoplasmic reticulum. Here authors use FRET and electrophysiology to show that R304W induces STIM1 conformational extension by a dual mechanism resulting in constitutive activation of Ca2+ channels.
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Affiliation(s)
- Marc Fahrner
- Institute of Biophysics, Johannes Kepler University Linz, Gruberstrasse 40, 4020, Linz, Austria.
| | - Michael Stadlbauer
- Institute of Biophysics, Johannes Kepler University Linz, Gruberstrasse 40, 4020, Linz, Austria
| | - Martin Muik
- Institute of Biophysics, Johannes Kepler University Linz, Gruberstrasse 40, 4020, Linz, Austria
| | - Petr Rathner
- Institute of Organic Chemistry, Johannes Kepler University Linz, Altenbergerstrasse 69, 4040, Linz, Austria
| | - Peter Stathopulos
- Department of Physiology and Pharmacology, University of Western Ontario, London, ON N6A 5C1, Canada
| | - Mitsu Ikura
- Princess Margaret Cancer Center, University Health Network, Toronto, ON M5G 1L7, Canada.,Department of Medical Biophysics, University of Toronto, Toronto, ON M5G 1L7, Canada
| | - Norbert Müller
- Institute of Organic Chemistry, Johannes Kepler University Linz, Altenbergerstrasse 69, 4040, Linz, Austria.,Faculty of Science, University of South Bohemia, Branišovská 1645/31A, 370 05, České Budějovice, Czech Republic
| | - Christoph Romanin
- Institute of Biophysics, Johannes Kepler University Linz, Gruberstrasse 40, 4020, Linz, Austria.
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Korzeniowski MK, Wisniewski E, Baird B, Holowka DA, Balla T. Molecular anatomy of the early events in STIM1 activation - oligomerization or conformational change? J Cell Sci 2017; 130:2821-2832. [PMID: 28724757 DOI: 10.1242/jcs.205583] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2017] [Accepted: 07/11/2017] [Indexed: 12/19/2022] Open
Abstract
Decreased luminal endoplasmic reticulum (ER) Ca2+ concentration triggers oligomerization and clustering of the ER Ca2+ sensor STIM1 to promote its association with plasma membrane Orai1 Ca2+ channels leading to increased Ca2+ influx. A key step in STIM1 activation is the release of its SOAR domain from an intramolecular clamp formed with the STIM1 first coiled-coil (CC1) region. Using a truncated STIM1(1-343) molecule that captures or releases the isolated SOAR domain depending on luminal ER Ca2+ concentrations, we analyzed the early molecular events that control the intramolecular clamp formed between the CC1 and SOAR domains. We found that STIM1 forms constitutive dimers, and its CC1 domain can bind the SOAR domain of another STIM1 molecule in trans. Artificial oligomerization failed to liberate the SOAR domain or activate STIM1 unless the luminal Ca2+-sensing domains were removed. We propose that the release of SOAR from its CC1 interaction is controlled by changes in the orientation of the two CC1 domains in STIM1 dimers. Ca2+ unbinding in the STIM1 luminal domains initiates the conformational change allowing SOAR domain liberation and clustering, leading to Orai1 channel activation.
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Affiliation(s)
- Marek K Korzeniowski
- Section on Molecular Signal Transduction, Program for Developmental Neuroscience, Eunice Kennedy Shriver NICHD, National Institutes of Health, Bethesda, MD 20892, USA.,Department of Chemistry and Chemical Biology, Cornell University, Ithaca, NY 14853, USA
| | - Eva Wisniewski
- Section on Molecular Signal Transduction, Program for Developmental Neuroscience, Eunice Kennedy Shriver NICHD, National Institutes of Health, Bethesda, MD 20892, USA
| | - Barbara Baird
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, NY 14853, USA
| | - David A Holowka
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, NY 14853, USA
| | - Tamas Balla
- Section on Molecular Signal Transduction, Program for Developmental Neuroscience, Eunice Kennedy Shriver NICHD, National Institutes of Health, Bethesda, MD 20892, USA
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Stathopulos PB, Ikura M. Store operated calcium entry: From concept to structural mechanisms. Cell Calcium 2017; 63:3-7. [DOI: 10.1016/j.ceca.2016.11.005] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2016] [Revised: 11/24/2016] [Accepted: 11/24/2016] [Indexed: 11/16/2022]
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Lopez JJ, Salido GM, Rosado JA. Cardiovascular and Hemostatic Disorders: SOCE and Ca 2+ Handling in Platelet Dysfunction. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2017; 993:453-472. [PMID: 28900928 DOI: 10.1007/978-3-319-57732-6_23] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Among the Ca2+ entry mechanisms in platelets, store-operated Ca2+ entry (SOCE) plays a prominent role as it is necessary to achieve full activation of platelet functions and replenish intracellular Ca2+ stores. In platelets, as in other non-excitable cells, SOCE has been reported to involve the activation of plasma membrane channels by the ER Ca2+ sensor STIM1. Despite electrophysiological studies are not possible in human platelets, indirect analyses have revealed that the Ca2+-permeable channels involve Orai1 and, most likely, TRPC1 subunits. A relevant role for the latter has not been found in mouse platelets. There is a body of evidence revealing a number of abnormalities in SOCE or in its molecular regulators that result in qualitative platelet disorders and, as a consequence, altered platelet responsiveness upon stimulation with multiple physiological agonists. Platelet SOCE abnormalities include STIM1 and Orai1 mutations. This chapter summarizes the current knowledge in this field, as well as the disorders associated to platelet SOCE dysfunction.
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Affiliation(s)
- Jose J Lopez
- Cell Physiology Research Group, Department of Physiology, University of Extremadura, Cáceres, Spain
| | - Gines M Salido
- Cell Physiology Research Group, Department of Physiology, University of Extremadura, Cáceres, Spain
| | - Juan A Rosado
- Cell Physiology Research Group, Department of Physiology, University of Extremadura, Cáceres, Spain.
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31
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Abstract
Ca2+ entry into the cell via store-operated Ca2+ release-activated Ca2+ (CRAC) channels triggers diverse signaling cascades that affect cellular processes like cell growth, gene regulation, secretion, and cell death. These store-operated Ca2+ channels open after depletion of intracellular Ca2+ stores, and their main features are fully reconstituted by the two molecular key players: the stromal interaction molecule (STIM) and Orai. STIM represents an endoplasmic reticulum-located Ca2+ sensor, while Orai forms a highly Ca2+-selective ion channel in the plasma membrane. Functional as well as mutagenesis studies together with structural insights about STIM and Orai proteins provide a molecular picture of the interplay of these two key players in the CRAC signaling cascade. This review focuses on the main experimental advances in the understanding of the STIM1-Orai choreography, thereby establishing a portrait of key mechanistic steps in the CRAC channel signaling cascade. The focus is on the activation of the STIM proteins, the subsequent coupling of STIM1 to Orai1, and the consequent structural rearrangements that gate the Orai channels into the open state to allow Ca2+ permeation into the cell.
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Affiliation(s)
- Isabella Derler
- Institute of Biophysics, Johannes Kepler University of Linz, Linz, Austria; and
| | - Isaac Jardin
- Department of Physiology, University of Extremadura, Cáceres, Spain
| | - Christoph Romanin
- Institute of Biophysics, Johannes Kepler University of Linz, Linz, Austria; and
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Frischauf I, Fahrner M, Jardín I, Romanin C. The STIM1: Orai Interaction. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2016; 898:25-46. [PMID: 27161223 DOI: 10.1007/978-3-319-26974-0_2] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Ca(2+) influx via store-operated Ca(2+) release activated Ca(2+) (CRAC) channels represents a main signalling pathway for a variety of cell functions, including T-cell activation as well as mast-cell degranulation. Depletion of [Ca(2+)]ER results in activation of Ca(2+) channels within the plasmamembrane that mediate sustained Ca(2+) influx which is required for refilling Ca(2+) stores and down-stream Ca(2+) signalling. The CRAC channel is the best characterized store-operated channel (SOC) with well-defined electrophysiological properties. In recent years, the molecular components of the CRAC channel have been defined. The ER - located Ca(2+)-sensor, STIM1 and the Ca(2+)-selective ion pore, Orai1 in the membrane are sufficient to fully reconstitute CRAC currents. Stromal interaction molecule (STIM) 1 is localized in the ER, senses [Ca(2+)]ER and activates the CRAC channel upon store depletion by direct binding to Orai1 in the plasmamembrane. The identification of STIM1 and Orai1 and recently the structural resolution of both proteins by X-ray crystallography and nuclear magnetic resonance substantiated many findings from structure-function studies which has substantially improved the understanding of CRAC channel activation. Within this review, we summarize the functional and structural mechanisms of CRAC channel regulation, present a detailed overview of the STIM1/Orai1 signalling pathway where we focus on the critical domains mediating interactions and on the ion permeation pathway. We portray a mechanistic view of the steps in the dynamics of CRAC channel signalling ranging from STIM1 oligomerization over STIM1-Orai1 coupling to CRAC channel activation and permeation.
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Affiliation(s)
| | - Marc Fahrner
- Institute of Biophysics, University of Linz, Linz, Austria
| | - Isaac Jardín
- Department of Physiology, University of Extremadura, Cáceres, Spain
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Abstract
Ca(2+) release-activated Ca(2+) (CRAC) channels mediate a specific form of Ca(2+) influx called store-operated Ca(2+) entry (SOCE) that contributes to the function of many cell types. CRAC channels are composed of ORAI1 proteins located in the plasma membrane, which form its ion-conducting pore. ORAI1 channels are activated by stromal interaction molecule (STIM) 1 and STIM2 located in the endoplasmic reticulum. Loss- and gain-of-function gene mutations in ORAI1 and STIM1 in human patients cause distinct disease syndromes. CRAC channelopathy is caused by loss-of-function mutations in ORAI1 and STIM1 that abolish CRAC channel function and SOCE; it is characterized by severe combined immunodeficiency (SCID)-like disease, autoimmunity, muscular hypotonia, and ectodermal dysplasia, with defects in sweat gland function and dental enamel formation. The latter defect emphasizes an important role of CRAC channels in tooth development. By contrast, autosomal dominant gain-of-function mutations in ORAI1 and STIM1 result in constitutive CRAC channel activation, SOCE, and increased intracellular Ca(2+) levels that are associated with an overlapping spectrum of diseases, including nonsyndromic tubular aggregate myopathy (TAM) and York platelet and Stormorken syndromes. The latter two syndromes are defined, besides myopathy, by thrombocytopenia, thrombopathy, and bleeding diathesis. The fact that myopathy results from both loss- and gain-of-function mutations in ORAI1 and STIM1 highlights the importance of CRAC channels for Ca(2+) homeostasis in skeletal muscle function. The cellular dysfunction and clinical disease spectrum observed in mutant patients provide important information about the molecular regulation of ORAI1 and STIM1 proteins and the role of CRAC channels in human physiology.
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Affiliation(s)
- Rodrigo S Lacruz
- Department of Basic Science and Craniofacial Biology, New York University College of Dentistry, New York, New York
| | - Stefan Feske
- Department of Pathology, New York University School of Medicine, New York, New York
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Marshall CB, Nishikawa T, Osawa M, Stathopulos PB, Ikura M. Calmodulin and STIM proteins: Two major calcium sensors in the cytoplasm and endoplasmic reticulum. Biochem Biophys Res Commun 2015; 460:5-21. [PMID: 25998729 DOI: 10.1016/j.bbrc.2015.01.106] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2015] [Accepted: 01/22/2015] [Indexed: 01/22/2023]
Abstract
The calcium (Ca(2+)) ion is a universal signalling messenger which plays vital physiological roles in all eukaryotes. To decode highly regulated intracellular Ca(2+) signals, cells have evolved a number of sensor proteins that are ideally adapted to respond to a specific range of Ca(2+) levels. Among many such proteins, calmodulin (CaM) is a multi-functional cytoplasmic Ca(2+) sensor with a remarkable ability to interact with and regulate a plethora of structurally diverse target proteins. CaM achieves this 'multi-talented' functionality through two EF-hand domains, each with an independent capacity to bind targets, and an adaptable flexible linker. By contrast, stromal interaction molecule-1 and -2 (STIMs) have evolved for a specific role in endoplasmic reticulum (ER) Ca(2+) sensing using EF-hand machinery analogous to CaM; however, whereas CaM structurally adjusts to dissimilar binding partners, STIMs use the EF-hand machinery to self-regulate the stability of the Ca(2+) sensing domain. The molecular mechanisms underlying the Ca(2+)-dependent signal transduction by CaM and STIMs have revealed a remarkable repertoire of actions and underscore the flexibility of nature in molecular evolution and adaption to discrete Ca(2+) levels. Recent genomic sequencing efforts have uncovered a number of disease-associated mutations in both CaM and STIM1. This article aims to highlight the most recent key structural and functional findings in the CaM and STIM fields, and discusses how these two Ca(2+) sensor proteins execute their biological functions.
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Affiliation(s)
- Christopher B Marshall
- Princess Margaret Cancer Centre, University Health Network and University of Toronto, Toronto, Ontario, M5G 1L7, Canada
| | - Tadateru Nishikawa
- Princess Margaret Cancer Centre, University Health Network and University of Toronto, Toronto, Ontario, M5G 1L7, Canada
| | - Masanori Osawa
- Graduate School of Pharmaceutical Sciences, The University of Tokyo, Hongo, Tokyo, 113-0033, Japan
| | - Peter B Stathopulos
- Department of Physiology and Pharmacology, Schulich School of Medicine and Dentistry, University of Western Ontario, London, Ontario, N6A 5C1, Canada.
| | - Mitsuhiko Ikura
- Princess Margaret Cancer Centre, University Health Network and University of Toronto, Toronto, Ontario, M5G 1L7, Canada.
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Morin G, Bruechle NO, Singh AR, Knopp C, Jedraszak G, Elbracht M, Brémond-Gignac D, Hartmann K, Sevestre H, Deutz P, Hérent D, Nürnberg P, Roméo B, Konrad K, Mathieu-Dramard M, Oldenburg J, Bourges-Petit E, Shen Y, Zerres K, Ouadid-Ahidouch H, Rochette J. Gain-of-Function Mutation in STIM1 (P.R304W) Is Associated with Stormorken Syndrome. Hum Mutat 2015; 35:1221-32. [PMID: 25044882 DOI: 10.1002/humu.22621] [Citation(s) in RCA: 88] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2014] [Accepted: 07/03/2014] [Indexed: 12/21/2022]
Abstract
Stormorken syndrome is a rare autosomal dominant disorder characterized by a phenotype that includes miosis, thrombocytopenia/thrombocytopathy with bleeding time diathesis, intellectual disability, mild hypocalcemia, muscle fatigue, asplenia, and ichthyosis. Using targeted sequencing and whole-exome sequencing, we identified the c.910C > T transition in a STIM1 allele (p.R304W) only in patients and not in their unaffected family members. STIM1 encodes stromal interaction molecule 1 protein (STIM1), which is a finely tuned endoplasmic reticulum Ca(2+) sensor. The effect of the mutation on the structure of STIM1 was investigated by molecular modeling, and its effect on function was explored by calcium imaging experiments. Results obtained from calcium imaging experiments using transfected cells together with fibroblasts from one patient are in agreement with impairment of calcium homeostasis. We show that the STIM1 p.R304W variant may affect the conformation of the inhibitory helix and unlock the inhibitory state of STIM1. The p.R304W mutation causes a gain of function effect associated with an increase in both resting Ca(2+) levels and store-operated calcium entry. Our study provides evidence that Stormorken syndrome may result from a single-gene defect, which is consistent with Mendelian-dominant inheritance.
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Affiliation(s)
- Gilles Morin
- Department of Molecular and Clinical Genetics, EA 4666, CHU d'Amiens, Université de Picardie Jules Verne, Amiens, France
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Misceo D, Holmgren A, Louch WE, Holme PA, Mizobuchi M, Morales RJ, De Paula AM, Stray-Pedersen A, Lyle R, Dalhus B, Christensen G, Stormorken H, Tjønnfjord GE, Frengen E. A dominant STIM1 mutation causes Stormorken syndrome. Hum Mutat 2014; 35:556-64. [PMID: 24619930 DOI: 10.1002/humu.22544] [Citation(s) in RCA: 122] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2014] [Accepted: 03/04/2014] [Indexed: 12/11/2022]
Abstract
Stormorken syndrome is a rare autosomal-dominant disease with mild bleeding tendency, thrombocytopathy, thrombocytopenia, mild anemia, asplenia, tubular aggregate myopathy, miosis, headache, and ichthyosis. A heterozygous missense mutation in STIM1 exon 7 (c.910C>T; p.Arg304Trp) (NM_003156.3) was found to segregate with the disease in six Stormorken syndrome patients in four families. Upon sensing Ca(2+) depletion in the endoplasmic reticulum lumen, STIM1 undergoes a conformational change enabling it to interact with and open ORAI1, a Ca(2+) release-activated Ca(2+) channel located in the plasma membrane. The STIM1 mutation found in Stormorken syndrome patients is located in the coiled-coil 1 domain, which might play a role in keeping STIM1 inactive. In agreement with a possible gain-of-function mutation in STIM1, blood platelets from patients were in a preactivated state with high exposure of aminophospholipids on the outer surface of the plasma membrane. Resting Ca(2+) levels were elevated in platelets from the patients compared with controls, and store-operated Ca(2+) entry was markedly attenuated, further supporting constitutive activity of STIM1 and ORAI1. Thus, our data are compatible with a near-maximal activation of STIM1 in Stormorken syndrome patients. We conclude that the heterozygous mutation c.910C>T causes the complex phenotype that defines this syndrome.
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Affiliation(s)
- Doriana Misceo
- Department of Medical Genetics, University of Oslo and Oslo University Hospital, Oslo, Norway
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Activating mutations in STIM1 and ORAI1 cause overlapping syndromes of tubular myopathy and congenital miosis. Proc Natl Acad Sci U S A 2014; 111:4197-202. [PMID: 24591628 DOI: 10.1073/pnas.1312520111] [Citation(s) in RCA: 184] [Impact Index Per Article: 18.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Signaling through the store-operated Ca(2+) release-activated Ca(2+) (CRAC) channel regulates critical cellular functions, including gene expression, cell growth and differentiation, and Ca(2+) homeostasis. Loss-of-function mutations in the CRAC channel pore-forming protein ORAI1 or the Ca(2+) sensing protein stromal interaction molecule 1 (STIM1) result in severe immune dysfunction and nonprogressive myopathy. Here, we identify gain-of-function mutations in the cytoplasmic domain of STIM1 (p.R304W) associated with thrombocytopenia, bleeding diathesis, miosis, and tubular myopathy in patients with Stormorken syndrome, and in ORAI1 (p.P245L), associated with a Stormorken-like syndrome of congenital miosis and tubular aggregate myopathy but without hematological abnormalities. Heterologous expression of STIM1 p.R304W results in constitutive activation of the CRAC channel in vitro, and spontaneous bleeding accompanied by reduced numbers of thrombocytes in zebrafish embryos, recapitulating key aspects of Stormorken syndrome. p.P245L in ORAI1 does not make a constitutively active CRAC channel, but suppresses the slow Ca(2+)-dependent inactivation of the CRAC channel, thus also functioning as a gain-of-function mutation. These data expand our understanding of the phenotypic spectrum of dysregulated CRAC channel signaling, advance our knowledge of the molecular function of the CRAC channel, and suggest new therapies aiming at attenuating store-operated Ca(2+) entry in the treatment of patients with Stormorken syndrome and related pathologic conditions.
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