1
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Naillat F, Deshar G, Hankkila A, Rak-Raszewska A, Sharma A, Prunskaite-Hyyrylainen R, Railo A, Shan J, Vainio SJ. Calcium signaling induces partial EMT and renal fibrosis in a Wnt4 mCherry knock-in mouse model. Biochim Biophys Acta Mol Basis Dis 2024; 1870:167180. [PMID: 38653356 DOI: 10.1016/j.bbadis.2024.167180] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2023] [Revised: 04/04/2024] [Accepted: 04/14/2024] [Indexed: 04/25/2024]
Abstract
The renal tubular epithelial cells (TEC) have a strong capacity for repair after acute injury, but when this mechanism becomes uncontrollable, it leads to chronic kidney diseases (CKD). Indeed, in progress toward CKDs, the TECs may dedifferentiate, undergo epithelial-to-mesenchyme transition (EMT), and promote inflammation and fibrosis. Given the critical role of Wnt4 signaling in kidney ontogenesis, we addressed whether changes in this signaling are connected to renal inflammation and fibrosis by taking advantage of a knock-in Wnt4mCh/mCh mouse. While the Wnt4mCh/mCh embryos appeared normal, the corresponding mice, within one month, developed CKD-related phenotypes, such as pro-inflammatory responses including T-cell/macrophage influx, expression of fibrotic markers, and epithelial cell damage with a partial EMT. The Wnt signal transduction component β-catenin remained unchanged, while calcium signaling is induced in the injured TECs involving Nfat and Tfeb transcription factors. We propose that the Wnt4 signaling pathway is involved in repairing the renal injury, and when the signal is overdriven, CKD is established.
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Affiliation(s)
- Florence Naillat
- Faculty of Biochemistry and Molecular Medicine, University of Oulu, Finland.
| | - Ganga Deshar
- Faculty of Biochemistry and Molecular Medicine, University of Oulu, Finland
| | - Anni Hankkila
- Faculty of Biochemistry and Molecular Medicine, University of Oulu, Finland
| | | | - Abhishek Sharma
- Faculty of Biochemistry and Molecular Medicine, University of Oulu, Finland
| | | | - Antti Railo
- Faculty of Biochemistry and Molecular Medicine, University of Oulu, Finland
| | - Jingdong Shan
- Faculty of Biochemistry and Molecular Medicine, University of Oulu, Finland
| | - Seppo J Vainio
- Faculty of Biochemistry and Molecular Medicine, University of Oulu, Finland; Infotech Oulu, Kvantum Institute, University of Oulu, Finland
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2
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Humer C, Schindl R, Sallinger M. Crosstalk between TPC2 and IP 3R regulates Ca 2+ signals. Trends Cell Biol 2024; 34:352-354. [PMID: 38494377 DOI: 10.1016/j.tcb.2024.03.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2024] [Revised: 02/29/2024] [Accepted: 03/01/2024] [Indexed: 03/19/2024]
Abstract
Calcium (Ca2+) plays a pivotal role in cellular signal transmission by triggering downstream signaling in response to an increase in the cytosolic Ca2+ concentration. Intracellular organelles serve as Ca2+ stores that induce differently shaped Ca2+ signals. We discuss a study by Yuan et al. that investigated the interplay between the lysosomal two-pore channel 2 (TPC2) and endoplasmic reticulum (ER)-localized inositol 1,4,5-trisphosphate receptors (IP3Rs).
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Affiliation(s)
- Christina Humer
- Institute of Biophysics, Johannes Kepler University Linz, Linz, Austria
| | - Rainer Schindl
- Department of Medical Physics and Biophysics, Medical University of Graz, Graz, Austria.
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3
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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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4
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Courjaret R, Prakriya M, Machaca K. SOCE as a regulator of neuronal activity. J Physiol 2024; 602:1449-1462. [PMID: 37029630 DOI: 10.1113/jp283826] [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: 01/08/2023] [Accepted: 03/28/2023] [Indexed: 04/09/2023] Open
Abstract
Store operated Ca2+ entry (SOCE) is a ubiquitous signalling module with established roles in the immune system, secretion and muscle development. Recent evidence supports a complex role for SOCE in the nervous system. In this review we present an update of the current knowledge on SOCE function in the brain with a focus on its role as a regulator of brain activity and excitability.
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Affiliation(s)
- Raphael Courjaret
- Calcium Signaling Group, Research Department, Weill Cornell Medicine Qatar, Qatar Foundation, Doha, Qatar
- Department of Physiology and Biophysics, Weill Cornell Medicine, New York, New York, USA
| | - Murali Prakriya
- Department of Pharmacology, Northwestern University, Feinberg School of Medicine, Chicago, Illinois, USA
| | - Khaled Machaca
- Calcium Signaling Group, Research Department, Weill Cornell Medicine Qatar, Qatar Foundation, Doha, Qatar
- Department of Physiology and Biophysics, Weill Cornell Medicine, New York, New York, USA
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5
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Kuczyńska M, Moskot M, Gabig-Cimińska M. Insights into Autophagic Machinery and Lysosomal Function in Cells Involved in the Psoriatic Immune-Mediated Inflammatory Cascade. Arch Immunol Ther Exp (Warsz) 2024; 72:aite-2024-0005. [PMID: 38409665 DOI: 10.2478/aite-2024-0005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2023] [Accepted: 12/08/2023] [Indexed: 02/28/2024]
Abstract
Impaired autophagy, due to the dysfunction of lysosomal organelles, contributes to maladaptive responses by pathways central to the immune system. Deciphering the immune-inflammatory ecosystem is essential, but remains a major challenge in terms of understanding the mechanisms responsible for autoimmune diseases. Accumulating evidence implicates a role that is played by a dysfunctional autophagy-lysosomal pathway (ALP) and an immune niche in psoriasis (Ps), one of the most common chronic skin diseases, characterized by the co-existence of autoimmune and autoinflammatory responses. The dysregulated autophagy associated with the defective lysosomal system is only one aspect of Ps pathogenesis. It probably cannot fully explain the pathomechanism involved in Ps, but it is likely important and should be seriously considered in Ps research. This review provides a recent update on discoveries in the field. Also, it sheds light on how the dysregulation of intracellular pathways, coming from modulated autophagy and endolysosomal trafficking, characteristic of key players of the disease, i.e., skin-resident cells, as well as circulating immune cells, may be responsible for immune impairment and the development of Ps.
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Affiliation(s)
- Martyna Kuczyńska
- Department of Medical Biology and Genetics, University of Gdańsk, Gdańsk, Poland
| | - Marta Moskot
- Department of Medical Biology and Genetics, University of Gdańsk, Gdańsk, Poland
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6
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Henry C, Carreras-Sureda A, Demaurex N. Enforced tethering elongates the cortical endoplasmic reticulum and limits store-operated calcium entry. J Cell Sci 2022; 135:274483. [PMID: 35191477 PMCID: PMC8995094 DOI: 10.1242/jcs.259313] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2021] [Accepted: 02/14/2022] [Indexed: 12/03/2022] Open
Abstract
Recruitment of STIM proteins to cortical endoplasmic reticulum (cER) domains forming membrane contact sites (MCSs) mediate the store-operated Ca2+ entry (SOCE) pathway essential for human immunity. The cER is dynamically regulated by STIM and tethering proteins during SOCE, but the ultrastructural rearrangement and functional consequences of cER remodeling are unknown. Here, we express natural (E-Syt1 and E-Syt2) and artificial (MAPPER-S and MAPPER-L) protein tethers in HEK-293T cells and correlate the changes in cER length and gap distance, as measured by electron microscopy, with ionic fluxes. We found that native cER cisternae extended during store depletion and remained elongated at a constant ER-plasma membrane (PM) gap distance during subsequent Ca2+ elevations. Tethering proteins enhanced store-dependent cER expansion, anchoring the enlarged cER at tether-specific gap distances of 12-15 nm (E-Syts) and 5-9 nm (MAPPERs). Cells with artificially extended cER had reduced SOCE and reduced agonist-induced Ca2+ release. SOCE remained modulated by calmodulin and exhibited enhanced Ca2+-dependent inhibition. We propose that cER expansion mediated by ER-PM tethering at a close distance negatively regulates SOCE by confining STIM-ORAI complexes to the periphery of enlarged cER sheets, a process that might participate in the termination of store-operated Ca2+ entry. Summary: ER-PM tethering at close distance limits Ca2+ entry by confining STIM-ORAI complexes to the periphery of contact sites.
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Affiliation(s)
- Christopher Henry
- Department of Cell Physiology and Metabolism, University of Geneva, Geneva, 1211, Switzerland
| | - Amado Carreras-Sureda
- Department of Cell Physiology and Metabolism, University of Geneva, Geneva, 1211, Switzerland
| | - Nicolas Demaurex
- Department of Cell Physiology and Metabolism, University of Geneva, Geneva, 1211, Switzerland
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7
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Humer C, Romanin C, Höglinger C. Highlighting the Multifaceted Role of Orai1 N-Terminal- and Loop Regions for Proper CRAC Channel Functions. Cells 2022; 11:371. [PMID: 35159181 PMCID: PMC8834118 DOI: 10.3390/cells11030371] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2021] [Revised: 01/14/2022] [Accepted: 01/15/2022] [Indexed: 11/16/2022] Open
Abstract
Orai1, the Ca2+-selective pore in the plasma membrane, is one of the key components of the Ca2+release-activated Ca2+ (CRAC) channel complex. Activated by the Ca2+ sensor in the endoplasmic reticulum (ER) membrane, stromal interaction molecule 1 (STIM1), via direct interaction when ER luminal Ca2+ levels recede, Orai1 helps to maintain Ca2+ homeostasis within a cell. It has already been proven that the C-terminus of Orai1 is indispensable for channel activation. However, there is strong evidence that for CRAC channels to function properly and maintain all typical hallmarks, such as selectivity and reversal potential, additional parts of Orai1 are needed. In this review, we focus on these sites apart from the C-terminus; namely, the second loop and N-terminus of Orai1 and on their multifaceted role in the functioning of CRAC channels.
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Affiliation(s)
| | | | - Carmen Höglinger
- Institute of Biophysics, Johannes Kepler University Linz, Gruberstrasse 40, 4020 Linz, Austria; (C.H.); (C.R.)
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8
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Gammons J, Halpage J, Mancarella S. Mapping the Proximity Interaction Network of STIM1 Reveals New Mechanisms of Cytoskeletal Regulation. Cells 2021; 10:2701. [PMID: 34685680 PMCID: PMC8535089 DOI: 10.3390/cells10102701] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2021] [Revised: 10/01/2021] [Accepted: 10/01/2021] [Indexed: 11/16/2022] Open
Abstract
Stromal interaction molecule 1 (STIM1) resides primarily in the sarco/endoplasmic reticulum, where it senses intraluminal Ca2+ levels and activates Orai channels on the plasma membrane to initiate Ca2+ influx. We have previously shown that STIM1 is involved in the dynamic remodeling of the actin cytoskeleton. However, the downstream effectors of STIM1 that lead to cytoskeletal remodeling are not known. The proximity-labeling technique (BioID) can capture weak and transient protein-protein interactions, including proteins that reside in the close vicinity of the bait, but that may not be direct binders. Hence, in the present study, we investigated the STIM1 interactome using the BioID technique. A promiscuous biotin ligase was fused to the cytoplasmic C-terminus of STIM1 and was stably expressed in a mouse embryonic fibroblast (MEF) cell line. Screening of biotinylated proteins identified several high confidence targets. Here, we report Gelsolin (GSN) as a new member of the STIM1 interactome. GSN is a Ca2+-dependent actin-severing protein that promotes actin filament assembly and disassembly. Results were validated using knockdown approaches and immunostaining. We tested our results in neonatal cardiomyocytes where STIM1 overexpression induced altered actin dynamics and cytoskeletal instability. This is the first time that BioID assay was used to investigate the STIM1 interactome. Our work highlights the role of STIM1/GSN in the structure and function of the cytoskeleton.
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Affiliation(s)
| | | | - Salvatore Mancarella
- Health Sciences Center, Department of Physiology, University of Tennessee, Memphis, TN 38163, USA; (J.G.); (J.H.)
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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: 7] [Impact Index Per Article: 2.3] [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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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:membranes10120425. [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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11
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Waldherr L, Tiffner A, Mishra D, Sallinger M, Schober R, Frischauf I, Schmidt T, Handl V, Sagmeister P, Köckinger M, Derler I, Üçal M, Bonhenry D, Patz S, Schindl R. Blockage of Store-Operated Ca 2+ Influx by Synta66 is Mediated by Direct Inhibition of the Ca 2+ Selective Orai1 Pore. Cancers (Basel) 2020; 12:E2876. [PMID: 33036292 PMCID: PMC7600887 DOI: 10.3390/cancers12102876] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2020] [Revised: 09/29/2020] [Accepted: 09/30/2020] [Indexed: 12/14/2022] Open
Abstract
The Ca2+ sensor STIM1 and the Ca2+ channel Orai1 that form the store-operated Ca2+ (SOC) channel complex are key targets for drug development. Selective SOC inhibitors are currently undergoing clinical evaluation for the treatment of auto-immune and inflammatory responses and are also deemed promising anti-neoplastic agents since SOC channels are linked with enhanced cancer cell progression. Here, we describe an investigation of the site of binding of the selective inhibitor Synta66 to the SOC channel Orai1 using docking and molecular dynamics simulations, and live cell recordings. Synta66 binding was localized to the extracellular site close to the transmembrane (TM)1 and TM3 helices and the extracellular loop segments, which, importantly, are adjacent to the Orai1-selectivity filter. Synta66-sensitivity of the Orai1 pore was, in fact, diminished by both Orai1 mutations affecting Ca2+ selectivity and permeation of Na+ in the absence of Ca2+. Synta66 also efficiently blocked SOC in three glioblastoma cell lines but failed to interfere with cell viability, division and migration. These experiments provide new structural and functional insights into selective drug inhibition of the Orai1 Ca2+ channel by a high-affinity pore blocker.
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Affiliation(s)
- Linda Waldherr
- Gottfried Schatz Research Centre, Medical University of Graz, A-8010 Graz, Austria; (L.W.); (R.S.); (T.S.)
| | - Adela Tiffner
- Institute of Biophysics, JKU Life Science Centre, Johannes Kepler University Linz, A-4020 Linz, Austria; (A.T.); (M.S.); (I.F.); (I.D.)
| | - Deepti Mishra
- Centre for Nanobiology and Structural Biology, Academy of Sciences of the Czech Republic, 373 33 Nové Hrady, Czech Republic;
| | - Matthias Sallinger
- Institute of Biophysics, JKU Life Science Centre, Johannes Kepler University Linz, A-4020 Linz, Austria; (A.T.); (M.S.); (I.F.); (I.D.)
| | - Romana Schober
- Gottfried Schatz Research Centre, Medical University of Graz, A-8010 Graz, Austria; (L.W.); (R.S.); (T.S.)
- Institute of Biophysics, JKU Life Science Centre, Johannes Kepler University Linz, A-4020 Linz, Austria; (A.T.); (M.S.); (I.F.); (I.D.)
| | - Irene Frischauf
- Institute of Biophysics, JKU Life Science Centre, Johannes Kepler University Linz, A-4020 Linz, Austria; (A.T.); (M.S.); (I.F.); (I.D.)
| | - Tony Schmidt
- Gottfried Schatz Research Centre, Medical University of Graz, A-8010 Graz, Austria; (L.W.); (R.S.); (T.S.)
| | - Verena Handl
- Department of Neurosurgery, Medical University of Graz, A-8010 Graz, Austria; (V.H.); (M.Ü.)
| | - Peter Sagmeister
- Institute of Chemistry, University of Graz, Heinrichstraße 28, A-8010 Graz, Austria; (P.S.); (M.K.)
| | - Manuel Köckinger
- Institute of Chemistry, University of Graz, Heinrichstraße 28, A-8010 Graz, Austria; (P.S.); (M.K.)
| | - Isabella Derler
- Institute of Biophysics, JKU Life Science Centre, Johannes Kepler University Linz, A-4020 Linz, Austria; (A.T.); (M.S.); (I.F.); (I.D.)
| | - Muammer Üçal
- Department of Neurosurgery, Medical University of Graz, A-8010 Graz, Austria; (V.H.); (M.Ü.)
| | - Daniel Bonhenry
- Centre for Nanobiology and Structural Biology, Academy of Sciences of the Czech Republic, 373 33 Nové Hrady, Czech Republic;
| | - Silke Patz
- Department of Neurosurgery, Medical University of Graz, A-8010 Graz, Austria; (V.H.); (M.Ü.)
| | - Rainer Schindl
- Gottfried Schatz Research Centre, Medical University of Graz, A-8010 Graz, Austria; (L.W.); (R.S.); (T.S.)
- Institute of Biophysics, JKU Life Science Centre, Johannes Kepler University Linz, A-4020 Linz, Austria; (A.T.); (M.S.); (I.F.); (I.D.)
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12
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Sallinger M, Tiffner A, Schmidt T, Bonhenry D, Waldherr L, Frischauf I, Lunz V, Derler I, Schober R, Schindl R. Luminal STIM1 Mutants that Cause Tubular Aggregate Myopathy Promote Autophagic Processes. Int J Mol Sci 2020; 21:E4410. [PMID: 32575830 PMCID: PMC7352373 DOI: 10.3390/ijms21124410] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2020] [Revised: 06/17/2020] [Accepted: 06/19/2020] [Indexed: 12/21/2022] Open
Abstract
Stromal interaction molecule 1 (STIM1) is a ubiquitously expressed Ca2+ sensor protein that induces permeation of Orai Ca2+ channels upon endoplasmic reticulum Ca2+-store depletion. A drop in luminal Ca2+ causes partial unfolding of the N-terminal STIM1 domains and thus initial STIM1 activation. We compared the STIM1 structure upon Ca2+ depletion from our molecular dynamics (MD) simulations with a recent 2D NMR structure. Simulation- and structure-based results showed unfolding of two α-helices in the canonical and in the non-canonical EF-hand. Further, we structurally and functionally evaluated mutations in the non-canonical EF-hand that have been shown to cause tubular aggregate myopathy. We found these mutations to cause full constitutive activation of Ca2+-release-activated Ca2+ currents (ICRAC) and to promote autophagic processes. Specifically, heterologously expressed STIM1 mutations in the non-canonical EF-hand promoted translocation of the autophagy transcription factors microphthalmia-associated transcription factor (MITF) and transcription factor EB (TFEB) into the nucleus. These STIM1 mutations additionally stimulated an enhanced production of autophagosomes. In summary, mutations in STIM1 that cause structural unfolding promoted Ca2+ down-stream activation of autophagic processes.
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Affiliation(s)
- Matthias Sallinger
- Institute of Biophysics, JKU Life Science Center, Johannes Kepler University Linz, A-4020 Linz, Austria; (M.S.); (A.T.); (I.F.); (V.L.); (I.D.)
| | - Adéla Tiffner
- Institute of Biophysics, JKU Life Science Center, Johannes Kepler University Linz, A-4020 Linz, Austria; (M.S.); (A.T.); (I.F.); (V.L.); (I.D.)
| | - Tony Schmidt
- Gottfried Schatz Research Center, Medical University of Graz, A-8010 Graz, Austria; (T.S.); (L.W.)
| | - Daniel Bonhenry
- Center for Nanobiology and Structural Biology, Institute of Microbiology, Academy of Sciences of the Czech Republic, CZ-373 33 Nove Hrady, Czech Republic;
| | - Linda Waldherr
- Gottfried Schatz Research Center, Medical University of Graz, A-8010 Graz, Austria; (T.S.); (L.W.)
| | - Irene Frischauf
- Institute of Biophysics, JKU Life Science Center, Johannes Kepler University Linz, A-4020 Linz, Austria; (M.S.); (A.T.); (I.F.); (V.L.); (I.D.)
| | - Victoria Lunz
- Institute of Biophysics, JKU Life Science Center, Johannes Kepler University Linz, A-4020 Linz, Austria; (M.S.); (A.T.); (I.F.); (V.L.); (I.D.)
| | - Isabella Derler
- Institute of Biophysics, JKU Life Science Center, Johannes Kepler University Linz, A-4020 Linz, Austria; (M.S.); (A.T.); (I.F.); (V.L.); (I.D.)
| | - Romana Schober
- Institute of Biophysics, JKU Life Science Center, Johannes Kepler University Linz, A-4020 Linz, Austria; (M.S.); (A.T.); (I.F.); (V.L.); (I.D.)
- Gottfried Schatz Research Center, Medical University of Graz, A-8010 Graz, Austria; (T.S.); (L.W.)
| | - Rainer Schindl
- Gottfried Schatz Research Center, Medical University of Graz, A-8010 Graz, Austria; (T.S.); (L.W.)
- BioTechMed-Graz, A-8010 Graz, Austria
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13
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Qin X, Liu L, Lee SK, Alsina A, Liu T, Wu C, Park H, Yu C, Kim H, Chu J, Triller A, Tang BZ, Hyeon C, Park CY, Park H. Increased Confinement and Polydispersity of STIM1 and Orai1 after Ca 2+ Store Depletion. Biophys J 2019; 118:70-84. [PMID: 31818466 DOI: 10.1016/j.bpj.2019.11.019] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2019] [Revised: 11/14/2019] [Accepted: 11/18/2019] [Indexed: 12/18/2022] Open
Abstract
STIM1 (a Ca2+ sensor in the endoplasmic reticulum (ER) membrane) and Orai1 (a pore-forming subunit of the Ca2+-release-activated calcium channel in the plasma membrane) diffuse in the ER membrane and plasma membrane, respectively. Upon depletion of Ca2+ stores in the ER, STIM1 translocates to the ER-plasma membrane junction and binds Orai1 to trigger store-operated Ca2+ entry. However, the motion of STIM1 and Orai1 during this process and its roles to Ca2+ entry is poorly understood. Here, we report real-time tracking of single STIM1 and Orai1 particles in the ER membrane and plasma membrane in living cells before and after Ca2+ store depletion. We found that the motion of single STIM1 and Orai1 particles exhibits anomalous diffusion both before and after store depletion, and their mobility-measured by the radius of gyration of the trajectories, mean-square displacement, and generalized diffusion coefficient-decreases drastically after store depletion. We also found that the measured displacement distribution is non-Gaussian, and the non-Gaussian parameter drastically increases after store depletion. Detailed analyses and simulations revealed that single STIM1 and Orai1 particles are confined in the compartmentalized membrane both before and after store depletion, and the changes in the motion after store depletion are explained by increased confinement and polydispersity of STIM1-Orai1 complexes formed at the ER-plasma membrane junctions. Further simulations showed that this increase in the confinement and polydispersity after store depletion localizes a rapid increase of Ca2+ influx, which can facilitate the rapid activation of local Ca2+ signaling pathways and the efficient replenishing of Ca2+ store in the ER in store-operated Ca2+ entry.
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Affiliation(s)
- Xianan Qin
- Department of Physics, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong
| | - Lei Liu
- School of Computational Sciences, Korea Institute for Advanced Study, Seoul, Korea
| | - Sang Kwon Lee
- Department of Biological Sciences, School of Life Sciences, Ulsan National Institute of Science and Technology, Ulsan, Korea
| | - Adolfo Alsina
- Department of Physics, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong; Max Planck Institute for the Physics of Complex Systems, Dresden, Germany
| | - Teng Liu
- Department of Physics, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong
| | | | - Hojeong Park
- Division of Biomedical Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong
| | | | - Hajin Kim
- Department of Biomedical Engineering and Department of Physics, Ulsan National Institute of Science and Technology, Ulsan, Korea
| | - Jun Chu
- Research Lab for Biomedical Optics and Molecular Imaging, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China
| | - Antoine Triller
- Biologie Cellulaire de la Synapse N&P, IBENS, Institut de Biologie de L'ENS, Ecole Normale Supérieure, Paris, France
| | - Ben Zhong Tang
- Division of Biomedical Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong; Department of Chemistry, Kowloon, Hong Kong, China, Kowloon, Hong Kong, China
| | - Changbong Hyeon
- School of Computational Sciences, Korea Institute for Advanced Study, Seoul, Korea.
| | - Chan Young Park
- Department of Biological Sciences, School of Life Sciences, Ulsan National Institute of Science and Technology, Ulsan, Korea.
| | - Hyokeun Park
- Department of Physics, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong; Division of Life Science; State Key Laboratory of Molecular Neuroscience, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China.
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14
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Schober R, Bonhenry D, Lunz V, Zhu J, Krizova A, Frischauf I, Fahrner M, Zhang M, Waldherr L, Schmidt T, Derler I, Stathopulos PB, Romanin C, Ettrich RH, Schindl R. Sequential activation of STIM1 links Ca 2+ with luminal domain unfolding. Sci Signal 2019; 12:eaax3194. [PMID: 31744929 DOI: 10.1126/scisignal.aax3194] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
The stromal interaction molecule 1 (STIM1) has two important functions, Ca2+ sensing within the endoplasmic reticulum and activation of the store-operated Ca2+ channel Orai1, enabling plasma-membrane Ca2+ influx. We combined molecular dynamics (MD) simulations with live-cell recordings and determined the sequential Ca2+-dependent conformations of the luminal STIM1 domain upon activation. Furthermore, we identified the residues within the canonical and noncanonical EF-hand domains that can bind to multiple Ca2+ ions. In MD simulations, a single Ca2+ ion was sufficient to stabilize the luminal STIM1 complex. Ca2+ store depletion destabilized the two EF hands, triggering disassembly of the hydrophobic cleft that they form together with the stable SAM domain. Point mutations associated with tubular aggregate myopathy or cancer that targeted the canonical EF hand, and the hydrophobic cleft yielded constitutively clustered STIM1, which was associated with activation of Ca2+ entry through Orai1 channels. On the basis of our results, we present a model of STIM1 Ca2+ binding and refine the currently known initial steps of STIM1 activation on a molecular level.
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Affiliation(s)
- Romana Schober
- Institute of Biophysics, JKU Life Science Center, Johannes Kepler University Linz, A-4020 Linz, Austria
| | - Daniel Bonhenry
- Center for Nanobiology and Structural Biology, Institute of Microbiology, Academy of Sciences of the Czech Republic, Nove Hrady CZ-373 33, Czech Republic
| | - Victoria Lunz
- Institute of Biophysics, JKU Life Science Center, Johannes Kepler University Linz, A-4020 Linz, Austria
| | - Jinhui Zhu
- Schulich Dentistry, Schulich School of Medicine and Dentistry, University of Western Ontario, London, Ontario N6A 5C1, Canada
- Department of Physiology and Pharmacology, Schulich School of Medicine and Dentistry, University of Western Ontario, London, Ontario N6A 5C1, Canada
| | - Adela Krizova
- Institute of Biophysics, JKU Life Science Center, Johannes Kepler University Linz, A-4020 Linz, Austria
| | - Irene Frischauf
- Institute of Biophysics, JKU Life Science Center, Johannes Kepler University Linz, A-4020 Linz, Austria
| | - Marc Fahrner
- Institute of Biophysics, JKU Life Science Center, Johannes Kepler University Linz, A-4020 Linz, Austria
| | - MengQi Zhang
- Department of Physiology and Pharmacology, Schulich School of Medicine and Dentistry, University of Western Ontario, London, Ontario N6A 5C1, Canada
- Faculty of Medicine, University of Ottawa, Ottawa, Ontario K1H 8M5, Canada
| | - 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
| | - Isabella Derler
- Institute of Biophysics, JKU Life Science Center, Johannes Kepler University Linz, A-4020 Linz, Austria
| | - Peter B Stathopulos
- Department of Physiology and Pharmacology, Schulich School of Medicine and Dentistry, University of Western Ontario, London, Ontario N6A 5C1, Canada
| | - Christoph Romanin
- Institute of Biophysics, JKU Life Science Center, Johannes Kepler University Linz, A-4020 Linz, Austria
| | - Rüdiger H Ettrich
- Center for Nanobiology and Structural Biology, Institute of Microbiology, Academy of Sciences of the Czech Republic, Nove Hrady CZ-373 33, Czech Republic.
- College of Biomedical Sciences, Larkin University, Miami, FL 33169, USA
| | - Rainer Schindl
- Gottfried Schatz Research Center, Medical University of Graz, A-8010 Graz, Austria.
- BioTechMed-Graz, A-8010 Graz, Austria
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