1
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Proteomic mapping and optogenetic manipulation of membrane contact sites. Biochem J 2022; 479:1857-1875. [PMID: 36111979 PMCID: PMC9555801 DOI: 10.1042/bcj20220382] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2022] [Revised: 08/31/2022] [Accepted: 09/01/2022] [Indexed: 11/17/2022]
Abstract
Membrane contact sites (MCSs) mediate crucial physiological processes in eukaryotic cells, including ion signaling, lipid metabolism, and autophagy. Dysregulation of MCSs is closely related to various diseases, such as type 2 diabetes mellitus (T2DM), neurodegenerative diseases, and cancers. Visualization, proteomic mapping and manipulation of MCSs may help the dissection of the physiology and pathology MCSs. Recent technical advances have enabled better understanding of the dynamics and functions of MCSs. Here we present a summary of currently known functions of MCSs, with a focus on optical approaches to visualize and manipulate MCSs, as well as proteomic mapping within MCSs.
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2
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Sarcoplasmic Reticulum Ca2+ Dysregulation in the Pathophysiology of Inherited Arrhythmia: An Update. Biochem Pharmacol 2022; 200:115059. [DOI: 10.1016/j.bcp.2022.115059] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2022] [Revised: 04/18/2022] [Accepted: 04/19/2022] [Indexed: 11/19/2022]
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3
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Zhang N, Pan H, Liang X, Xie J, Han W. The roles of transmembrane family proteins in the regulation of store-operated Ca 2+ entry. Cell Mol Life Sci 2022; 79:118. [PMID: 35119538 PMCID: PMC11071953 DOI: 10.1007/s00018-021-04034-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2021] [Revised: 11/09/2021] [Accepted: 11/10/2021] [Indexed: 12/15/2022]
Abstract
Store-operated Ca2+ entry (SOCE) is a major pathway for calcium signaling, which regulates almost every biological process, involving cell proliferation, differentiation, movement and death. Stromal interaction molecule (STIM) and ORAI calcium release-activated calcium modulator (ORAI) are the two major proteins involved in SOCE. With the deepening of studies, more and more proteins are found to be able to regulate SOCE, among which the transmembrane (TMEM) family proteins are worth paying more attention. In addition, the ORAI proteins belong to the TMEM family themselves. As the name suggests, TMEM family is a type of proteins that spans biological membranes including plasma membrane and membrane of organelles. TMEM proteins are in a large family with more than 300 proteins that have been already identified, while the functional knowledge about the proteins is preliminary. In this review, we mainly summarized the TMEM proteins that are involved in SOCE, to better describe a picture of the interaction between STIM and ORAI proteins during SOCE and its downstream signaling pathways, as well as to provide an idea for the study of the TMEM family proteins.
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Affiliation(s)
- Ningxia Zhang
- Department of Medical Oncology, Sir Run Run Shaw Hospital, College of Medicine, Zhejiang University, Hangzhou, Zhejiang, People's Republic of China
| | - Hongming Pan
- Department of Medical Oncology, Sir Run Run Shaw Hospital, College of Medicine, Zhejiang University, Hangzhou, Zhejiang, People's Republic of China
| | - Xiaojing Liang
- Department of Medical Oncology, Sir Run Run Shaw Hospital, College of Medicine, Zhejiang University, Hangzhou, Zhejiang, People's Republic of China
| | - Jiansheng Xie
- Department of Medical Oncology, Sir Run Run Shaw Hospital, College of Medicine, Zhejiang University, Hangzhou, Zhejiang, People's Republic of China.
- Laboratory of Cancer Biology, Institute of Clinical Science, Sir Run Run Shaw Hospital, College of Medicine, Zhejiang University, Hangzhou, Zhejiang, People's Republic of China.
| | - Weidong Han
- Department of Medical Oncology, Sir Run Run Shaw Hospital, College of Medicine, Zhejiang University, Hangzhou, Zhejiang, People's Republic of China.
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4
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van der Merwe M, van Niekerk G, Fourie C, du Plessis M, Engelbrecht AM. The impact of mitochondria on cancer treatment resistance. Cell Oncol (Dordr) 2021; 44:983-995. [PMID: 34244972 DOI: 10.1007/s13402-021-00623-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2021] [Accepted: 06/24/2021] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND The ability of cancer cells to develop treatment resistance is one of the primary factors that prevent successful treatment. Although initially thought to be dysfunctional in cancer, mitochondria are significant players that mediate treatment resistance. Literature indicates that cancer cells reutilize their mitochondria to facilitate cancer progression and treatment resistance. However, the mechanisms by which the mitochondria promote treatment resistance have not yet been fully elucidated. CONCLUSIONS AND PERSPECTIVES Here, we describe various means by which mitochondria can promote treatment resistance. For example, mutations in tricarboxylic acid (TCA) cycle enzymes, i.e., fumarate hydratase and isocitrate dehydrogenase, result in the accumulation of the oncometabolites fumarate and 2-hydroxyglutarate, respectively. These oncometabolites may promote treatment resistance by upregulating the nuclear factor erythroid 2-related factor 2 (Nrf2) pathway, inhibiting the anti-tumor immune response, or promoting angiogenesis. Furthermore, stromal cells can donate intact mitochondria to cancer cells after therapy to restore mitochondrial functionality and facilitate treatment resistance. Targeting mitochondria is, therefore, a feasible strategy that may dampen treatment resistance. Analysis of tumoral DNA may also be used to guide treatment choices. It will indicate whether enzymatic mutations are present in the TCA cycle and, if so, whether the mutations or their downstream signaling pathways can be targeted. This may improve treatment outcomes by inhibiting treatment resistance or promoting the effectiveness of anti-angiogenic agents or immunotherapy.
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Affiliation(s)
- Michelle van der Merwe
- Department of Physiological Sciences, Stellenbosch University, Stellenbosch, South Africa.
| | - Gustav van Niekerk
- Department of Physiological Sciences, Stellenbosch University, Stellenbosch, South Africa
| | - Carla Fourie
- Department of Physiological Sciences, Stellenbosch University, Stellenbosch, South Africa
| | - Manisha du Plessis
- Department of Physiological Sciences, Stellenbosch University, Stellenbosch, South Africa
| | - Anna-Mart Engelbrecht
- Department of Physiological Sciences, Stellenbosch University, Stellenbosch, South Africa
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5
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Nan J, Li J, Lin Y, Saif Ur Rahman M, Li Z, Zhu L. The interplay between mitochondria and store-operated Ca 2+ entry: Emerging insights into cardiac diseases. J Cell Mol Med 2021; 25:9496-9512. [PMID: 34564947 PMCID: PMC8505841 DOI: 10.1111/jcmm.16941] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2021] [Revised: 08/20/2021] [Accepted: 09/08/2021] [Indexed: 12/14/2022] Open
Abstract
Store‐operated Ca2+ entry (SOCE) machinery, including Orai channels, TRPCs, and STIM1, is key to cellular calcium homeostasis. The following characteristics of mitochondria are involved in the physiological and pathological regulation of cells: mitochondria mediate calcium uptake through calcium uniporters; mitochondria are regulated by mitochondrial dynamic related proteins (OPA1, MFN1/2, and DRP1) and form mitochondrial networks through continuous fission and fusion; mitochondria supply NADH to the electron transport chain through the Krebs cycle to produce ATP; under stress, mitochondria will produce excessive reactive oxygen species to regulate mitochondria‐endoplasmic reticulum interactions and the related signalling pathways. Both SOCE and mitochondria play critical roles in mediating cardiac hypertrophy, diabetic cardiomyopathy, and cardiac ischaemia‐reperfusion injury. All the mitochondrial characteristics mentioned above are determinants of SOCE activity, and vice versa. Ca2+ signalling dictates the reciprocal regulation between mitochondria and SOCE under the specific pathological conditions of cardiomyocytes. The coupling of mitochondria and SOCE is essential for various pathophysiological processes in the heart. Herein, we review the research focussing on the reciprocal regulation between mitochondria and SOCE and provide potential interplay patterns in cardiac diseases.
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Affiliation(s)
- Jinliang Nan
- Provincial Key Cardiovascular Research Laboratory, Department of Cardiology, The Second Affiliated Hospital, Zhejiang University School of Medicine, Zhejiang Province, Hangzhou, China
| | - Jiamin Li
- Provincial Key Cardiovascular Research Laboratory, Department of Cardiology, The Second Affiliated Hospital, Zhejiang University School of Medicine, Zhejiang Province, Hangzhou, China
| | - Yinuo Lin
- Wenzhou Municipal Key Cardiovascular Research Laboratory, Department of Cardiology, The First Affiliated Hospital, Wenzhou Medical University, Zhejiang Province, Wenzhou, China
| | - Muhammad Saif Ur Rahman
- Zhejiang University-University of Edinburgh Biomedical Institute, Haining, Zhejiang, China.,Clinical Research Center, The Second Affiliated Hospital Zhejiang University School of Medicine, Hangzhou, China
| | - Zhengzheng Li
- Department of Neurology, Research Institute of Experimental Neurobiology, The First Affiliated Hospital, Wenzhou Medical University, Zhejiang Province, Wenzhou, China
| | - Lingjun Zhu
- Provincial Key Cardiovascular Research Laboratory, Department of Cardiology, The Second Affiliated Hospital, Zhejiang University School of Medicine, Zhejiang Province, Hangzhou, China
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6
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Ma G, He L, Liu S, Xie J, Huang Z, Jing J, Lee YT, Wang R, Luo H, Han W, Huang Y, Zhou Y. Optogenetic engineering to probe the molecular choreography of STIM1-mediated cell signaling. Nat Commun 2020; 11:1039. [PMID: 32098964 PMCID: PMC7042325 DOI: 10.1038/s41467-020-14841-9] [Citation(s) in RCA: 49] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2019] [Accepted: 02/06/2020] [Indexed: 02/07/2023] Open
Abstract
Genetically encoded photoswitches have enabled spatial and temporal control of cellular events to achieve tailored functions in living cells, but their applications to probe the structure-function relations of signaling proteins are still underexplored. We illustrate herein the incorporation of various blue light-responsive photoreceptors into modular domains of the stromal interaction molecule 1 (STIM1) to manipulate protein activity and faithfully recapitulate STIM1-mediated signaling events. Capitalizing on these optogenetic tools, we identify the molecular determinants required to mediate protein oligomerization, intramolecular conformational switch, and protein-target interactions. In parallel, we have applied these synthetic devices to enable light-inducible gating of calcium channels, conformational switch, dynamic protein-microtubule interactions and assembly of membrane contact sites in a reversible manner. Our optogenetic engineering approach can be broadly applied to aid the mechanistic dissection of cell signaling, as well as non-invasive interrogation of physiological processes with high precision. Optogenetic tools have been used to control cellular behaviours but their use to probe structure-function relations of signalling proteins are underexplored. Here the authors engineer optogenetic modules into STIM1 to dissect molecular details of STIM1-mediated signalling and control various cellular events.
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Affiliation(s)
- Guolin Ma
- Center for Translational Cancer Research, Institute of Biosciences and Technology, Texas A&M University, Houston, TX, 77030, USA
| | - Lian He
- Center for Translational Cancer Research, Institute of Biosciences and Technology, Texas A&M University, Houston, TX, 77030, USA
| | - Shuzhong Liu
- Center for Translational Cancer Research, Institute of Biosciences and Technology, Texas A&M University, Houston, TX, 77030, USA.,Department of Gastroenterology, Key Laboratory of Hubei Province for Digestive System Disease, Renmin Hospital of Wuhan University, Wuhan, 430060, China
| | - Jiansheng Xie
- Center for Translational Cancer Research, Institute of Biosciences and Technology, Texas A&M University, Houston, TX, 77030, USA.,Department of Medical Oncology, Laboratory of Cancer Biology, Institute of Clinical Science, Sir Run Run Shaw Hospital, College of Medicine, Zhejiang University, Hangzhou, Zhejiang, China
| | - Zixian Huang
- Center for Translational Cancer Research, Institute of Biosciences and Technology, Texas A&M University, Houston, TX, 77030, USA.,Department of Oral and Maxillofacial Surgery, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou, Guangdong, 510120, China
| | - Ji Jing
- Center for Translational Cancer Research, Institute of Biosciences and Technology, Texas A&M University, Houston, TX, 77030, USA
| | - Yi-Tsang Lee
- Center for Translational Cancer Research, Institute of Biosciences and Technology, Texas A&M University, Houston, TX, 77030, USA
| | - Rui Wang
- Center for Translational Cancer Research, Institute of Biosciences and Technology, Texas A&M University, Houston, TX, 77030, USA
| | - Hesheng Luo
- Department of Gastroenterology, Key Laboratory of Hubei Province for Digestive System Disease, Renmin Hospital of Wuhan University, Wuhan, 430060, China
| | - Weidong Han
- Department of Medical Oncology, Laboratory of Cancer Biology, Institute of Clinical Science, Sir Run Run Shaw Hospital, College of Medicine, Zhejiang University, Hangzhou, Zhejiang, China.
| | - Yun Huang
- Center for Epigenetics and Disease Prevention, Institute of Biosciences and Technology, Texas A&M University, Houston, TX, 77030, USA.
| | - Yubin Zhou
- Center for Translational Cancer Research, Institute of Biosciences and Technology, Texas A&M University, Houston, TX, 77030, USA. .,Department of Translational Medical Sciences, College of Medicine, Texas A&M University, Houston, TX, 77030, USA.
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7
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Larrea D, Pera M, Gonnelli A, Quintana-Cabrera R, Akman HO, Guardia-Laguarta C, Velasco KR, Area-Gomez E, Dal Bello F, De Stefani D, Horvath R, Shy ME, Schon EA, Giacomello M. MFN2 mutations in Charcot-Marie-Tooth disease alter mitochondria-associated ER membrane function but do not impair bioenergetics. Hum Mol Genet 2020; 28:1782-1800. [PMID: 30649465 PMCID: PMC6522073 DOI: 10.1093/hmg/ddz008] [Citation(s) in RCA: 65] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2018] [Revised: 11/27/2018] [Accepted: 12/31/2018] [Indexed: 12/23/2022] Open
Abstract
Charcot-Marie-Tooth disease (CMT) type 2A is a form of peripheral neuropathy, due almost exclusively to dominant mutations in the nuclear gene encoding the mitochondrial protein mitofusin-2 (MFN2). However, there is no understanding of the relationship of clinical phenotype to genotype. MFN2 has two functions: it promotes inter-mitochondrial fusion and mediates endoplasmic reticulum (ER)-mitochondrial tethering at mitochondria-associated ER membranes (MAM). MAM regulates a number of key cellular functions, including lipid and calcium homeostasis, and mitochondrial behavior. To date, no studies have been performed to address whether mutations in MFN2 in CMT2A patient cells affect MAM function, which might provide insight into pathogenesis. Using fibroblasts from three CMT2AMFN2 patients with different mutations in MFN2, we found that some, but not all, examined aspects of ER-mitochondrial connectivity and of MAM function were indeed altered, and correlated with disease severity. Notably, however, respiratory chain function in those cells was unimpaired. Our results suggest that CMT2AMFN2 is a MAM-related disorder but is not a respiratory chain-deficiency disease. The alterations in MAM function described here could also provide insight into the pathogenesis of other forms of CMT.
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Affiliation(s)
- Delfina Larrea
- Department of Neurology, Columbia University Medical Center, New York, NY, USA
| | - Marta Pera
- Department of Neurology, Columbia University Medical Center, New York, NY, USA
| | | | | | - H Orhan Akman
- Department of Neurology, Columbia University Medical Center, New York, NY, USA
| | | | - Kevin R Velasco
- Department of Neurology, Columbia University Medical Center, New York, NY, USA
| | - Estela Area-Gomez
- Department of Neurology, Columbia University Medical Center, New York, NY, USA
| | | | | | - Rita Horvath
- Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne, UK
| | - Michael E Shy
- Department of Neurology, University of Iowa, Iowa City, IA, USA
| | - Eric A Schon
- Department of Neurology, Columbia University Medical Center, New York, NY, USA.,Department of Genetics and Development, Columbia University Medical Center, New York, NY, USA
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8
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Bella P, Farini A, Banfi S, Parolini D, Tonna N, Meregalli M, Belicchi M, Erratico S, D'Ursi P, Bianco F, Legato M, Ruocco C, Sitzia C, Sangiorgi S, Villa C, D'Antona G, Milanesi L, Nisoli E, Mauri P, Torrente Y. Blockade of IGF2R improves muscle regeneration and ameliorates Duchenne muscular dystrophy. EMBO Mol Med 2020; 12:e11019. [PMID: 31793167 PMCID: PMC6949491 DOI: 10.15252/emmm.201911019] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2019] [Revised: 10/29/2019] [Accepted: 10/30/2019] [Indexed: 12/17/2022] Open
Abstract
Duchenne muscular dystrophy (DMD) is a debilitating fatal X-linked muscle disorder. Recent findings indicate that IGFs play a central role in skeletal muscle regeneration and development. Among IGFs, insulinlike growth factor 2 (IGF2) is a key regulator of cell growth, survival, migration and differentiation. The type 2 IGF receptor (IGF2R) modulates circulating and tissue levels of IGF2 by targeting it to lysosomes for degradation. We found that IGF2R and the store-operated Ca2+ channel CD20 share a common hydrophobic binding motif that stabilizes their association. Silencing CD20 decreased myoblast differentiation, whereas blockade of IGF2R increased proliferation and differentiation in myoblasts via the calmodulin/calcineurin/NFAT pathway. Remarkably, anti-IGF2R induced CD20 phosphorylation, leading to the activation of sarcoplasmic/endoplasmic reticulum Ca2+ -ATPase (SERCA) and removal of intracellular Ca2+ . Interestingly, we found that IGF2R expression was increased in dystrophic skeletal muscle of human DMD patients and mdx mice. Blockade of IGF2R by neutralizing antibodies stimulated muscle regeneration, induced force recovery and normalized capillary architecture in dystrophic mdx mice representing an encouraging starting point for the development of new biological therapies for DMD.
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Affiliation(s)
- Pamela Bella
- Stem Cell LaboratoryDepartment of Pathophysiology and TransplantationUnit of NeurologyFondazione IRCCS Ca’ Granda Ospedale Maggiore PoliclinicoCentro Dino FerrariUniversitá degli Studi di MilanoMilanItaly
| | - Andrea Farini
- Stem Cell LaboratoryDepartment of Pathophysiology and TransplantationUnit of NeurologyFondazione IRCCS Ca’ Granda Ospedale Maggiore PoliclinicoCentro Dino FerrariUniversitá degli Studi di MilanoMilanItaly
| | - Stefania Banfi
- Hematology Department Fondazione IRCCSDepartment of Oncology and Hemato‐oncologyIstituto Nazionale dei TumoriUniversitá degli Studi di MilanoMilanItaly
| | | | | | - Mirella Meregalli
- Stem Cell LaboratoryDepartment of Pathophysiology and TransplantationUnit of NeurologyFondazione IRCCS Ca’ Granda Ospedale Maggiore PoliclinicoCentro Dino FerrariUniversitá degli Studi di MilanoMilanItaly
| | - Marzia Belicchi
- Stem Cell LaboratoryDepartment of Pathophysiology and TransplantationUnit of NeurologyFondazione IRCCS Ca’ Granda Ospedale Maggiore PoliclinicoCentro Dino FerrariUniversitá degli Studi di MilanoMilanItaly
| | | | - Pasqualina D'Ursi
- Institute of Technologies in BiomedicineNational Research Council (ITB‐CNR)MilanItaly
| | | | - Mariella Legato
- Stem Cell LaboratoryDepartment of Pathophysiology and TransplantationUnit of NeurologyFondazione IRCCS Ca’ Granda Ospedale Maggiore PoliclinicoCentro Dino FerrariUniversitá degli Studi di MilanoMilanItaly
| | - Chiara Ruocco
- Department of Medical Biotechnology and Translational MedicineCenter for Study and Research on ObesityMilan UniversityMilanItaly
| | - Clementina Sitzia
- UOC SMEL‐1Scuola di Specializzazione di Patologia Clinica e Biochimica ClinicaUniversità degli Studi di MilanoMilanItaly
| | - Simone Sangiorgi
- Neurosurgery UnitDepartment of SurgeryASST Lariana‐S. Anna HospitalComoItaly
| | - Chiara Villa
- Stem Cell LaboratoryDepartment of Pathophysiology and TransplantationUnit of NeurologyFondazione IRCCS Ca’ Granda Ospedale Maggiore PoliclinicoCentro Dino FerrariUniversitá degli Studi di MilanoMilanItaly
| | - Giuseppe D'Antona
- Department of Public Health, Experimental and Forensic MedicinePavia UniversityPaviaItaly
| | - Luciano Milanesi
- Institute of Technologies in BiomedicineNational Research Council (ITB‐CNR)MilanItaly
| | - Enzo Nisoli
- Department of Medical Biotechnology and Translational MedicineCenter for Study and Research on ObesityMilan UniversityMilanItaly
| | - PierLuigi Mauri
- Institute of Technologies in BiomedicineNational Research Council (ITB‐CNR)MilanItaly
| | - Yvan Torrente
- Stem Cell LaboratoryDepartment of Pathophysiology and TransplantationUnit of NeurologyFondazione IRCCS Ca’ Granda Ospedale Maggiore PoliclinicoCentro Dino FerrariUniversitá degli Studi di MilanoMilanItaly
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9
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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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10
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Eckstein M, Vaeth M, Aulestia FJ, Costiniti V, Kassam SN, Bromage TG, Pedersen P, Issekutz T, Idaghdour Y, Moursi AM, Feske S, Lacruz RS. Differential regulation of Ca 2+ influx by ORAI channels mediates enamel mineralization. Sci Signal 2019; 12:12/578/eaav4663. [PMID: 31015290 DOI: 10.1126/scisignal.aav4663] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Store-operated Ca2+ entry (SOCE) channels are highly selective Ca2+ channels activated by the endoplasmic reticulum (ER) sensors STIM1 and STIM2. Their direct interaction with the pore-forming plasma membrane ORAI proteins (ORAI1, ORAI2, and ORAI3) leads to sustained Ca2+ fluxes that are critical for many cellular functions. Mutations in the human ORAI1 gene result in immunodeficiency, anhidrotic ectodermal dysplasia, and enamel defects. In our investigation of the role of ORAI proteins in enamel, we identified enamel defects in a patient with an ORAI1 null mutation. Targeted deletion of the Orai1 gene in mice showed enamel defects and reduced SOCE in isolated enamel cells. However, Orai2-/- mice showed normal enamel despite having increased SOCE in the enamel cells. Knockdown experiments in the enamel cell line LS8 suggested that ORAI2 and ORAI3 modulated ORAI1 function, with ORAI1 and ORAI2 being the main contributors to SOCE. ORAI1-deficient LS8 cells showed altered mitochondrial respiration with increased oxygen consumption rate and ATP, which was associated with altered redox status and enhanced ER Ca2+ uptake, likely due to S-glutathionylation of SERCA pumps. Our findings demonstrate an important role of ORAI1 in Ca2+ influx in enamel cells and establish a link between SOCE, mitochondrial function, and redox homeostasis.
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Affiliation(s)
- Miriam Eckstein
- Department of Basic Science and Craniofacial Biology, New York University College of Dentistry, New York, NY 10010, USA
| | - Martin Vaeth
- Department of Pathology, New York University School of Medicine, New York, NY 10016, USA
| | - Francisco J Aulestia
- Department of Basic Science and Craniofacial Biology, New York University College of Dentistry, New York, NY 10010, USA
| | - Veronica Costiniti
- Department of Basic Science and Craniofacial Biology, New York University College of Dentistry, New York, NY 10010, USA
| | - Serena N Kassam
- Department of Pediatric Dentistry, New York University College of Dentistry, New York, NY 10010, USA
| | - Timothy G Bromage
- Department of Basic Science and Craniofacial Biology, New York University College of Dentistry, New York, NY 10010, USA.,Department of Biomaterials, New York University College of Dentistry, New York, NY 10010, USA
| | - Pal Pedersen
- Carl Zeiss Microscopy, LLC, Thornwood, NY 10594, USA
| | - Thomas Issekutz
- Department of Pediatrics, Dalhousie University, Halifax, NS B3H 4R2, Canada
| | - Youssef Idaghdour
- Biology Program, Division of Science and Mathematics, New York University Abu Dhabi, Abu Dhabi, United Arab Emirates
| | - Amr M Moursi
- Department of Pediatric Dentistry, New York University College of Dentistry, New York, NY 10010, USA
| | - Stefan Feske
- Department of Pathology, New York University School of Medicine, New York, NY 10016, USA
| | - Rodrigo S Lacruz
- Department of Basic Science and Craniofacial Biology, New York University College of Dentistry, New York, NY 10010, USA.
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11
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Yang Z, Yan H, Dai W, Jing J, Yang Y, Mahajan S, Zhou Y, Li W, Macaubas C, Mellins ED, Shih CC, Fitzpatrick JAJ, Faccio R. Tmem178 negatively regulates store-operated calcium entry in myeloid cells via association with STIM1. J Autoimmun 2019; 101:94-108. [PMID: 31018906 DOI: 10.1016/j.jaut.2019.04.015] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2019] [Revised: 04/09/2019] [Accepted: 04/12/2019] [Indexed: 12/27/2022]
Abstract
Store-operated calcium entry (SOCE) modulates cytosolic calcium in multiple cells. Endoplasmic reticulum (ER)-localized STIM1 and plasma membrane (PM)-localized ORAI1 are two main components of SOCE. STIM1:ORAI1 association requires STIM1 oligomerization, its re-distribution to ER-PM junctions, and puncta formation. However, little is known about the negative regulation of these steps to prevent calcium overload. Here, we identified Tmem178 as a negative modulator of STIM1 puncta formation in myeloid cells. Using site-directed mutagenesis, co-immunoprecipitation assays and FRET imaging, we determined that Tmem178:STIM1 association occurs via their transmembrane motifs. Mutants that increase Tmem178:STIM1 association reduce STIM1 puncta formation, SOCE activation, impair inflammatory cytokine production in macrophages and osteoclastogenesis. Mutants that reduce Tmem178:STIM1 association reverse these effects. Furthermore, exposure to plasma from arthritic patients decreases Tmem178 expression, enhances SOCE activation and cytoplasmic calcium. In conclusion, Tmem178 modulates the rate-limiting step of STIM1 puncta formation and therefore controls SOCE in inflammatory conditions.
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Affiliation(s)
- Zhengfeng Yang
- Department of Orthopaedics, Washington University School of Medicine, St. Louis, MO, 63110, USA
| | - Hui Yan
- Department of Orthopaedics, Washington University School of Medicine, St. Louis, MO, 63110, USA
| | - Wentao Dai
- Shanghai Center for Bioinformation Technology & Shanghai Engineering Research Center of Pharmaceutical Translation, Shanghai Industrial Technology Institute, 1278 Keyuan Road, Shanghai, 201203, China
| | - Ji Jing
- Institute of Biosciences and Technology, Texas A&M University College of Medicine, Houston, TX 77030, USA
| | - Yihu Yang
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, MO, USA
| | - Sahil Mahajan
- Department of Orthopaedics, Washington University School of Medicine, St. Louis, MO, 63110, USA
| | - Yubin Zhou
- Institute of Biosciences and Technology, Texas A&M University College of Medicine, Houston, TX 77030, USA
| | - Weikai Li
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, MO, USA
| | - Claudia Macaubas
- Department of Pediatrics, Program in Immunology, Stanford University, Stanford, CA 94305, USA
| | - Elizabeth D Mellins
- Department of Pediatrics, Program in Immunology, Stanford University, Stanford, CA 94305, USA
| | - Chien-Cheng Shih
- Washington University Center for Cellular Imaging, Washington University School of Medicine, St. Louis, MO, 63110, USA
| | - James A J Fitzpatrick
- Washington University Center for Cellular Imaging, Washington University School of Medicine, St. Louis, MO, 63110, USA; Department of Cell Biology & Physiology, Washington University School of Medicine, St. Louis, MO, USA; Department of Neuroscience, Washington University School of Medicine, St. Louis, MO, USA; Department of Biomedical Engineering, Washington University, St. Louis, MO, USA
| | - Roberta Faccio
- Department of Orthopaedics, Washington University School of Medicine, St. Louis, MO, 63110, USA; Shriners Hospitals for Children, St. Louis MO, USA.
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12
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Liu Z, Li H, He L, Xiang Y, Tian C, Li C, Tan P, Jing J, Tian Y, Du L, Huang Y, Han L, Li M, Zhou Y. Discovery of Small-Molecule Inhibitors of the HSP90-Calcineurin-NFAT Pathway against Glioblastoma. Cell Chem Biol 2019; 26:352-365.e7. [PMID: 30639261 PMCID: PMC6430684 DOI: 10.1016/j.chembiol.2018.11.009] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2018] [Revised: 10/13/2018] [Accepted: 11/15/2018] [Indexed: 02/06/2023]
Abstract
Glioblastoma (GBM) is among the most common and malignant types of primary brain tumors in adults, with a dismal prognosis. Although alkylating agents such as temozolomide are widely applied as the first-line treatment for GBM, they often cause chemoresistance and remain ineffective with recurrent GBM. Alternative therapeutics against GBM are urgently needed in the clinic. We report herein the discovery of a class of inhibitors (YZ129 and its derivatives) of the calcineurin-NFAT pathway that exhibited potent anti-tumor activity against GBM. YZ129-induced GBM cell-cycle arrest at the G2/M phase promoted apoptosis and inhibited tumor cell proliferation and migration. At the molecular level, YZ129 directly engaged HSP90 to antagonize its chaperoning effect on calcineurin to abrogate NFAT nuclear translocation, and also suppressed other proto-oncogenic pathways including hypoxia, glycolysis, and the PI3K/AKT/mTOR signaling axis. Our data highlight the potential for targeting the cancer-promoting HSP90 chaperone network to treat GBM.
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Affiliation(s)
- Zhenzhen Liu
- Institute of Biosciences and Technology, College of Medicine, Texas A&M University, Houston, TX 77030, USA; Department of Medicinal Chemistry, Key Laboratory of Chemical Biology (MOE), School of Pharmacy, Shandong University, Jinan, Shandong 250012, China; Department of Pharmaceutical Engineering, School of Chemistry, Chemical Engineering and Materials Science, Shandong Normal University, Jinan, Shandong 250014, China
| | - Hongli Li
- Institute of Biosciences and Technology, College of Medicine, Texas A&M University, Houston, TX 77030, USA; Department of Histology and Embryology, Army Medical University, Chongqing 400038, China
| | - Lian He
- Institute of Biosciences and Technology, College of Medicine, Texas A&M University, Houston, TX 77030, USA
| | - Yu Xiang
- Department of Biochemistry and Molecular Biology, McGovern Medical School at the University of Texas Health Science Center, Houston, TX 77030, USA
| | - Chengsen Tian
- Department of Medicinal Chemistry, Key Laboratory of Chemical Biology (MOE), School of Pharmacy, Shandong University, Jinan, Shandong 250012, China; School of Chemistry and Chemical Engineering, Qilu Normal University, Jinan, Shandong 250200, China
| | - Can Li
- Institute of Biosciences and Technology, College of Medicine, Texas A&M University, Houston, TX 77030, USA
| | - Peng Tan
- Institute of Biosciences and Technology, College of Medicine, Texas A&M University, Houston, TX 77030, USA
| | - Ji Jing
- Institute of Biosciences and Technology, College of Medicine, Texas A&M University, Houston, TX 77030, USA
| | - Yanpin Tian
- Department of Histology and Embryology, Army Medical University, Chongqing 400038, China
| | - Lupei Du
- Department of Medicinal Chemistry, Key Laboratory of Chemical Biology (MOE), School of Pharmacy, Shandong University, Jinan, Shandong 250012, China
| | - Yun Huang
- Institute of Biosciences and Technology, College of Medicine, Texas A&M University, Houston, TX 77030, USA
| | - Leng Han
- Department of Biochemistry and Molecular Biology, McGovern Medical School at the University of Texas Health Science Center, Houston, TX 77030, USA.
| | - Minyong Li
- Department of Medicinal Chemistry, Key Laboratory of Chemical Biology (MOE), School of Pharmacy, Shandong University, Jinan, Shandong 250012, China; State Key Laboratory of Microbial Technology, Shandong University, Jinan, Shandong 250100, China.
| | - Yubin Zhou
- Institute of Biosciences and Technology, College of Medicine, Texas A&M University, Houston, TX 77030, USA; Department of Medical Physiology, College of Medicine, Texas A&M University, Temple, TX 76504, USA.
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13
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Hutchings CJ, Colussi P, Clark TG. Ion channels as therapeutic antibody targets. MAbs 2018; 11:265-296. [PMID: 30526315 PMCID: PMC6380435 DOI: 10.1080/19420862.2018.1548232] [Citation(s) in RCA: 74] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2018] [Revised: 11/01/2018] [Accepted: 11/03/2018] [Indexed: 12/12/2022] Open
Abstract
It is now well established that antibodies have numerous potential benefits when developed as therapeutics. Here, we evaluate the technical challenges of raising antibodies to membrane-spanning proteins together with enabling technologies that may facilitate the discovery of antibody therapeutics to ion channels. Additionally, we discuss the potential targeting opportunities in the anti-ion channel antibody landscape, along with a number of case studies where functional antibodies that target ion channels have been reported. Antibodies currently in development and progressing towards the clinic are highlighted.
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Affiliation(s)
| | | | - Theodore G. Clark
- TetraGenetics Inc, Arlington Massachusetts, USA
- Department of Microbiology and Immunology, Cornell University, Ithaca New York, USA
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14
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Chauhan AS, Liu X, Jing J, Lee H, Yadav RK, Liu J, Zhou Y, Gan B. STIM2 interacts with AMPK and regulates calcium-induced AMPK activation. FASEB J 2018; 33:2957-2970. [PMID: 30335546 PMCID: PMC6338636 DOI: 10.1096/fj.201801225r] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
AMPK is a crucial regulator of energy homeostasis that acts downstream of its upstream kinase liver kinase B1 (LKB1) and calcium/calmodulin-dependent protein kinase 2 (CaMKK2). LKB1 primarily phosphorylates AMPK after energy stress, whereas calcium-mediated activation of AMPK requires CaMKK2, although the regulatory mechanisms of calcium-mediated AMPK activation remain unclear. Using biochemical, microscopic, and genetic approaches, we demonstrate that the stromal interaction molecule (STIM)2, a calcium sensor, acts as a novel regulator of CaMKK2-AMPK signaling. We reveal that STIM2 interacts with AMPK and CaMKK2 and that the increase in intracellular calcium levels promotes AMPK colocalization and interaction with STIM2. We further show that STIM2 deficiency attenuates calcium-induced but not energy stress–induced AMPK activation, possibly by regulating the CaMKK2-AMPK interaction. Together, our results identify a previously unappreciated mechanism that modulates calcium-mediated AMPK activation.—Chauhan, A. S., Liu, X., Jing, J., Lee, H., Yadav, R. K., Liu, J., Zhou, Y., Gan B. STIM2 interacts with AMPK and regulates calcium-induced AMPK activation.
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Affiliation(s)
- Anoop Singh Chauhan
- Department of Experimental Radiation Oncology, The University of Texas M. D. Anderson Cancer Center, Houston, Texas, USA
| | - Xiaoguang Liu
- Department of Experimental Radiation Oncology, The University of Texas M. D. Anderson Cancer Center, Houston, Texas, USA
| | - Ji Jing
- Institute of Biosciences and Technology, Texas A&M University Health Science Center, Houston, Texas, USA
| | - Hyemin Lee
- Department of Experimental Radiation Oncology, The University of Texas M. D. Anderson Cancer Center, Houston, Texas, USA
| | - Raj Kumar Yadav
- Department of Experimental Radiation Oncology, The University of Texas M. D. Anderson Cancer Center, Houston, Texas, USA
| | - Jindou Liu
- Institute of Biosciences and Technology, Texas A&M University Health Science Center, Houston, Texas, USA
| | - Yubin Zhou
- Institute of Biosciences and Technology, Texas A&M University Health Science Center, Houston, Texas, USA.,Department of Medical Physiology, College of Medicine, Texas A&M University, Temple, Texas, USA
| | - Boyi Gan
- Department of Experimental Radiation Oncology, The University of Texas M. D. Anderson Cancer Center, Houston, Texas, USA.,Department of Molecular and Cellular Oncology, The University of Texas M. D. Anderson Cancer Center, Houston, Texas, USA.,UTHealth Graduate School of Biomedical Sciences, M. D. Anderson Cancer Center, Houston, Texas, USA
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15
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Nguyen NT, Ma G, Lin E, D'Souza B, Jing J, He L, Huang Y, Zhou Y. CRAC channel-based optogenetics. Cell Calcium 2018; 75:79-88. [PMID: 30199756 DOI: 10.1016/j.ceca.2018.08.007] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2018] [Accepted: 08/31/2018] [Indexed: 01/28/2023]
Abstract
Store-operated Ca²+ entry (SOCE) constitutes a major Ca2+ influx pathway in mammals to regulate a myriad of physiological processes, including muscle contraction, synaptic transmission, gene expression, and metabolism. In non-excitable cells, the Ca²+ release-activated Ca²+ (CRAC) channel, composed of ORAI and stromal interaction molecules (STIM), constitutes a prototypical example of SOCE to mediate Ca2+ entry at specialized membrane contact sites (MCSs) between the endoplasmic reticulum (ER) and the plasma membrane (PM). The key steps of SOCE activation include the oligomerization of the luminal domain of the ER-resident Ca2+ sensor STIM1 upon Ca²+ store depletion, subsequent signal propagation toward the cytoplasmic domain to trigger a conformational switch and overcome the intramolecular autoinhibition, and ultimate exposure of the minimal ORAI-activating domain to directly engage and gate ORAI channels in the plasma membrane. This exquisitely coordinated cellular event is also facilitated by the C-terminal polybasic domain of STIM1, which physically associates with negatively charged phosphoinositides embedded in the inner leaflet of the PM to enable efficient translocation of STIM1 into ER-PM MCSs. Here, we present recent progress in recapitulating STIM1-mediated SOCE activation by engineering CRAC channels with optogenetic approaches. These STIM1-based optogenetic tools make it possible to not only mechanistically recapture the key molecular steps of SOCE activation, but also remotely and reversibly control Ca²+-dependent cellular processes, inter-organellar tethering at MCSs, and transcriptional reprogramming when combined with CRISPR/Cas9-based genome-editing tools.
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Affiliation(s)
- Nhung Thi Nguyen
- Center for Translational Cancer Research, Institute of Biosciences and Technology, College of Medicine, Texas A&M University, Houston, TX 77030, USA
| | - Guolin Ma
- Center for Translational Cancer Research, Institute of Biosciences and Technology, College of Medicine, Texas A&M University, Houston, TX 77030, USA
| | - Eena Lin
- Center for Translational Cancer Research, Institute of Biosciences and Technology, College of Medicine, Texas A&M University, Houston, TX 77030, USA
| | - Brendan D'Souza
- Center for Translational Cancer Research, Institute of Biosciences and Technology, College of Medicine, Texas A&M University, Houston, TX 77030, USA
| | - Ji Jing
- Center for Translational Cancer Research, Institute of Biosciences and Technology, College of Medicine, Texas A&M University, Houston, TX 77030, USA
| | - Lian He
- Center for Translational Cancer Research, Institute of Biosciences and Technology, College of Medicine, Texas A&M University, Houston, TX 77030, USA
| | - Yun Huang
- Center for Epigenetics and Disease Prevention, Institute of Biosciences and Technology, College of Medicine, Texas A&M University, Houston, TX 77030, USA; Department of Molecular and Cellular Medicine, College of Medicine, Texas A&M University, College Station, TX 77843, USA
| | - Yubin Zhou
- Center for Translational Cancer Research, Institute of Biosciences and Technology, College of Medicine, Texas A&M University, Houston, TX 77030, USA; Department of Medical Physiology, College of Medicine, Texas A&M University, Temple, TX 76504, USA.
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16
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Ma G, Zhang Q, He L, Nguyen NT, Liu S, Gong Z, Huang Y, Zhou Y. Genetically encoded tags for real time dissection of protein assembly in living cells. Chem Sci 2018; 9:5551-5555. [PMID: 30061986 PMCID: PMC6048692 DOI: 10.1039/c8sc00839f] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2018] [Accepted: 05/22/2018] [Indexed: 12/21/2022] Open
Abstract
Simple methods with straightforward readouts that enable real-time interrogation of protein quaternary structure are much needed to facilitate the physicochemical characterization of proteins at the single-cell level. After screening over a series of microtubule (MT) binders, we report herein the development of two genetically encoded tags (designated as "MoTags" for the monomer/oligomer detection tag) that can be conveniently fused to a given protein to probe its oligomeric state in cellulo when combined with routine fluorescence microscopy. In their monomeric form, MoTags are evenly distributed in the cytosol; whereas oligomerization enables MoTags to label MT or track MT tips in an oligomeric state-dependent manner. We demonstrate here the broad utility of engineered MoTags to aid the determination of protein oligomeric states, dissection of protein structure and function, and monitoring of protein-target interactions under physiological conditions in living cells.
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Affiliation(s)
- Guolin Ma
- Center for Translational Cancer Research , Institute of Biosciences and Technology , College of Medicine , Texas A&M University , 2121 W Holcombe Blvd , Houston , TX 77030 , USA . ;
| | - Qian Zhang
- Center for Translational Cancer Research , Institute of Biosciences and Technology , College of Medicine , Texas A&M University , 2121 W Holcombe Blvd , Houston , TX 77030 , USA . ;
- Department of Infectious Diseases , Renmin Hospital of Wuhan University , Wuhan 430060 , China
| | - Lian He
- Center for Translational Cancer Research , Institute of Biosciences and Technology , College of Medicine , Texas A&M University , 2121 W Holcombe Blvd , Houston , TX 77030 , USA . ;
| | - Nhung T Nguyen
- Center for Translational Cancer Research , Institute of Biosciences and Technology , College of Medicine , Texas A&M University , 2121 W Holcombe Blvd , Houston , TX 77030 , USA . ;
| | - Shuzhong Liu
- Center for Translational Cancer Research , Institute of Biosciences and Technology , College of Medicine , Texas A&M University , 2121 W Holcombe Blvd , Houston , TX 77030 , USA . ;
| | - Zuojiong Gong
- Department of Infectious Diseases , Renmin Hospital of Wuhan University , Wuhan 430060 , China
| | - Yun Huang
- Center for Epigenetics and Disease Prevention , Institute of Biosciences and Technology , College of Medicine , Texas A&M University , 2121 W Holcombe Blvd , Houston , TX 77030 , USA .
- Department of Molecular and Cellular Medicine , College of Medicine , Texas A&M University , College Station , TX 77843 , USA
| | - Yubin Zhou
- Center for Translational Cancer Research , Institute of Biosciences and Technology , College of Medicine , Texas A&M University , 2121 W Holcombe Blvd , Houston , TX 77030 , USA . ;
- Department of Medical Physiology , College of Medicine , Texas A&M University , Temple , TX 76504 , USA
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17
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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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18
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Ma G, Zheng S, Ke Y, Zhou L, He L, Huang Y, Wang Y, Zhou Y. Molecular Determinants for STIM1 Activation During Store- Operated Ca2+ Entry. Curr Mol Med 2018; 17:60-69. [PMID: 28231751 DOI: 10.2174/1566524017666170220103731] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2017] [Revised: 01/31/2017] [Accepted: 02/01/2017] [Indexed: 12/25/2022]
Abstract
BACKGROUND STIM/ORAI-mediated store-operated Ca2+ entry (SOCE) mediates a myriad of Ca2+-dependent cellular activities in mammals. Genetic defects in STIM1/ORAI1 lead to devastating severe combined immunodeficiency; whereas gain-offunction mutations in STIM1/ORAI1 are intimately associated with tubular aggregate myopathy. At molecular level, a decrease in the Ca2+ concentrations within the lumen of endoplasmic reticulum (ER) initiates multimerization of the STIM1 luminal domain to switch on the STIM1 cytoplasmic domain to engage and gate ORAI channels, thereby leading to the ultimate Ca2+ influx from the extracellular space into the cytosol. Despite tremendous progress made in dissecting functional STIM1-ORAI1 coupling, the activation mechanism of SOCE remains to be fully characterized. OBJECTIVE AND METHODS Building upon a robust fluorescence resonance energy transfer assay designed to monitor STIM1 intramolecular autoinhibition, we aimed to systematically dissect the molecular determinants required for the activation and oligomerization of STIM1. RESULTS Here we showed that truncation of the STIM1 luminal domain predisposes STIM1 to adopt a more active conformation. Replacement of the single transmembrane (TM) domain of STIM1 by a more rigid dimerized TM domain of glycophorin A abolished STIM1 activation. But this adverse effect could be partially reversed by disrupting the TM dimerization interface. Moreover, our study revealed regions that are important for the optimal assembly of hetero-oligomers composed of full-length STIM1 with its minimal STIM1-ORAI activating region, SOAR. CONCLUSIONS Our study clarifies the roles of major STIM1 functional domains in maintaining a quiescent configuration of STIM1 to prevent preactivation of SOCE.
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Affiliation(s)
- G Ma
- Center for Translational Cancer Research, Institute of Biosciences and Technology, Texas A&M University, Houston, TX 77030. United States
| | - S Zheng
- Beijing Key Laboratory of Gene Resource and Molecular Development, College of Life Sciences, Beijing Normal University, Beijing 100875. China
| | - Y Ke
- Center for Translational Cancer Research, Institute of Biosciences and Technology, Texas A&M University, Houston, TX 77030. United States
| | - L Zhou
- Beijing Key Laboratory of Gene Resource and Molecular Development, College of Life Sciences, Beijing Normal University, Beijing 100875. China
| | - L He
- Center for Translational Cancer Research, Institute of Biosciences and Technology, Texas A&M University, Houston, TX 77030. United States
| | - Y Huang
- Center for Epigenetic and Disease Prevention, Institute of Biosciences and Technology, Texas A&M University, Houston, TX 77030. United States
| | - Y Wang
- Center for Translational Cancer Research, Institute of Biosciences and Technology, Texas A&M University System Health Science Center, 2121 W. Holcombe Blvd., Houston, TX 77030. United States
| | - Y Zhou
- Center for Translational Cancer Research, Institute of Biosciences and Technology, Texas A&M University System Health Science Center, 2121 W. Holcombe Blvd., Houston, TX 77030. United States
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19
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Subedi KP, Ong HL, Son GY, Liu X, Ambudkar IS. STIM2 Induces Activated Conformation of STIM1 to Control Orai1 Function in ER-PM Junctions. Cell Rep 2018; 23:522-534. [DOI: 10.1016/j.celrep.2018.03.065] [Citation(s) in RCA: 45] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2017] [Revised: 02/12/2018] [Accepted: 03/15/2018] [Indexed: 02/07/2023] Open
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20
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Abstract
The transmembrane docking of endoplasmic reticulum (ER) Ca2+-sensing STIM proteins with plasma membrane (PM) Orai Ca2+ channels is a critical but poorly understood step in Ca2+ signal generation. STIM1 protein dimers unfold to expose a discrete STIM-Orai activating region (SOAR1) that tethers and activates Orai1 channels within discrete ER-PM junctions. We reveal that each monomer within the SOAR dimer interacts independently with single Orai1 subunits to mediate cross-linking between Orai1 channels. Superresolution imaging and mobility measured by fluorescence recovery after photobleaching reveal that SOAR dimer cross-linking leads to substantial Orai1 channel clustering, resulting in increased efficacy and cooperativity of Orai1 channel function. A concatenated SOAR1 heterodimer containing one monomer point mutated at its critical Orai1 binding residue (F394H), although fully activating Orai channels, is completely defective in cross-linking Orai1 channels. Importantly, the naturally occurring STIM2 variant, STIM2.1, has an eight-amino acid insert in its SOAR unit that renders it functionally identical to the F394H mutant in SOAR1. Contrary to earlier predictions, the SOAR1-SOAR2.1 heterodimer fully activates Orai1 channels but prevents cross-linking and clustering of channels. Interestingly, combined expression of full-length STIM1 with STIM2.1 in a 5:1 ratio causes suppression of sustained agonist-induced Ca2+ oscillations and protects cells from Ca2+ overload, resulting from high agonist-induced Ca2+ release. Thus, STIM2.1 exerts a powerful regulatory effect on signal generation likely through preventing Orai1 channel cross-linking. Overall, STIM-mediated cross-linking of Orai1 channels is a hitherto unrecognized functional paradigm that likely provides an organizational microenvironment within ER-PM junctions with important functional impact on Ca2+ signal generation.
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21
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Nguyen NT, He L, Martinez-Moczygemba M, Huang Y, Zhou Y. Rewiring Calcium Signaling for Precise Transcriptional Reprogramming. ACS Synth Biol 2018; 7:814-821. [PMID: 29489336 DOI: 10.1021/acssynbio.7b00467] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Tools capable of modulating gene expression in living organisms are very useful for interrogating the gene regulatory network and controlling biological processes. The catalytically inactive CRISPR/Cas9 (dCas9), when fused with repressive or activating effectors, functions as a versatile platform to reprogram gene transcription at targeted genomic loci. However, without temporal control, the application of these reprogramming tools will likely cause off-target effects and lack strict reversibility. To overcome this limitation, we report herein the development of a chemical or light-inducible transcriptional reprogramming device that combines photoswitchable genetically encoded calcium actuators with dCas9 to control gene expression. By fusing an engineered Ca2+-responsive NFAT fragment with dCas9 and transcriptional coactivators, we harness the power of light to achieve photoinducible transcriptional reprogramming in mammalian cells. This synthetic system (designated CaRROT) can also be used to document calcium-dependent activity in mammals after exposure to ligands or chemicals that would elicit calcium response inside cells.
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22
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Ma G, He L, Jing J, Tan P, Huang Y, Zhou Y. Engineered Cross-Linking to Study the Pore Architecture of the CRAC Channel. Methods Mol Biol 2018; 1843:147-166. [PMID: 30203285 PMCID: PMC8935632 DOI: 10.1007/978-1-4939-8704-7_13] [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] [Indexed: 05/13/2024]
Abstract
ORAI1 constitutes the pore-forming subunit of the calcium release-activated calcium (CRAC) channel, a prototypical store-operated channel that is essential for the activation of cells of the immune system. Here we describe a convenient yet powerful cross-linking approach to examine the pore architecture of CRAC channels using ORAI1 proteins engineered to contain one or two cysteine residues. The generalizable cross-linking in situ approach can also be readily extended to study other integral membrane proteins expressed in various types of cells.
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Affiliation(s)
- Guolin Ma
- Center for Translational Cancer Research, Institute of Biosciences and Technology, College of Medicine, Texas A&M University, 2121 W. Holcombe Blvd, Houston, TX, USA
| | - Lian He
- Center for Translational Cancer Research, Institute of Biosciences and Technology, College of Medicine, Texas A&M University, 2121 W. Holcombe Blvd, Houston, TX, USA
| | - Ji Jing
- Center for Translational Cancer Research, Institute of Biosciences and Technology, College of Medicine, Texas A&M University, 2121 W. Holcombe Blvd, Houston, TX, USA
| | - Peng Tan
- Center for Translational Cancer Research, Institute of Biosciences and Technology, College of Medicine, Texas A&M University, 2121 W. Holcombe Blvd, Houston, TX, USA
| | - Yun Huang
- Center for Translational Cancer Research, Institute of Biosciences and Technology, College of Medicine, Texas A&M University, 2121 W. Holcombe Blvd, Houston, TX, USA
| | - Yubin Zhou
- Center for Translational Cancer Research, Institute of Biosciences and Technology, College of Medicine, Texas A&M University, 2121 W. Holcombe Blvd, Houston, TX, USA.
- Department of Medical Physiology, College of Medicine, Texas A&M University, Temple, TX, USA.
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23
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He L, Jing J, Zhu L, Tan P, Ma G, Zhang Q, Nguyen NT, Wang J, Zhou Y, Huang Y. Optical control of membrane tethering and interorganellar communication at nanoscales. Chem Sci 2017; 8:5275-5281. [PMID: 28959426 PMCID: PMC5606013 DOI: 10.1039/c7sc01115f] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2017] [Accepted: 05/23/2017] [Indexed: 12/11/2022] Open
Abstract
Endoplasmic reticulum (ER) forms an extensive intracellular membranous network in eukaryotes that dynamically connects and communicates with diverse subcellular compartments such as plasma membrane (PM) through membrane contact sites (MCSs), with the inter-membrane gaps separated by a distance of 10-40 nm. Phosphoinositides (PI) constitute an important class of cell membrane phospholipids shared by many MCSs to regulate a myriad of cellular events, including membrane trafficking, calcium homeostasis and lipid metabolism. By installing photosensitivity into a series of engineered PI-binding domains with minimal sizes, we have created an optogenetic toolkit (designated as 'OptoPB') to enable rapid and reversible control of protein translocation and inter-membrane tethering at MCSs. These genetically-encoded, single-component tools can be used as scaffolds for grafting lipid-binding domains to dissect molecular determinants that govern protein-lipid interactions in living cells. Furthermore, we have demonstrated the use of OptoPB as a versatile fusion tag to photomanipulate protein translocation toward PM for reprogramming of PI metabolism. When tethered to the ER membrane with the insertion of flexible spacers, OptoPB can be applied to reversibly photo-tune the gap distances at nanometer scales between the two organellar membranes at MCSs, and to gauge the distance requirement for the free diffusion of protein complexes into MCSs. Our modular optical tools will find broad applications in non-invasive and remote control of protein subcellular localization and interorganellar contact sites that are critical for cell signaling.
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Affiliation(s)
- Lian He
- Center for Translational Cancer Research , Institute of Biosciences and Technology , Department of Medical Physiology , College of Medicine , Texas A&M University , Houston , TX 77030 , USA .
| | - Ji Jing
- Center for Translational Cancer Research , Institute of Biosciences and Technology , Department of Medical Physiology , College of Medicine , Texas A&M University , Houston , TX 77030 , USA .
| | - Lei Zhu
- Key Laboratory of High Magnetic Field and Ion Beam Physical Biology , Chinese Academy of Sciences , Hefei 230031 , Anhui , China .
| | - Peng Tan
- Center for Translational Cancer Research , Institute of Biosciences and Technology , Department of Medical Physiology , College of Medicine , Texas A&M University , Houston , TX 77030 , USA .
| | - Guolin Ma
- Center for Translational Cancer Research , Institute of Biosciences and Technology , Department of Medical Physiology , College of Medicine , Texas A&M University , Houston , TX 77030 , USA .
| | - Qian Zhang
- Center for Translational Cancer Research , Institute of Biosciences and Technology , Department of Medical Physiology , College of Medicine , Texas A&M University , Houston , TX 77030 , USA .
- Department of Infectious Diseases , Renmin Hospital of Wuhan University , Wuhan , Hubei 430060 , China
| | - Nhung T Nguyen
- Center for Translational Cancer Research , Institute of Biosciences and Technology , Department of Medical Physiology , College of Medicine , Texas A&M University , Houston , TX 77030 , USA .
| | - Junfeng Wang
- Key Laboratory of High Magnetic Field and Ion Beam Physical Biology , Chinese Academy of Sciences , Hefei 230031 , Anhui , China .
| | - Yubin Zhou
- Center for Translational Cancer Research , Institute of Biosciences and Technology , Department of Medical Physiology , College of Medicine , Texas A&M University , Houston , TX 77030 , USA .
| | - Yun Huang
- Center for Epigenetics and Disease Prevention , Institute of Biosciences and Technology , Department of Medical Physiology , College of Medicine , Texas A&M University , Houston , TX 77030 , USA .
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Ma G, Wen S, He L, Huang Y, Wang Y, Zhou Y. Optogenetic toolkit for precise control of calcium signaling. Cell Calcium 2017; 64:36-46. [PMID: 28104276 PMCID: PMC5457325 DOI: 10.1016/j.ceca.2017.01.004] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2016] [Revised: 01/10/2017] [Accepted: 01/10/2017] [Indexed: 12/19/2022]
Abstract
Calcium acts as a second messenger to regulate a myriad of cell functions, ranging from short-term muscle contraction and cell motility to long-term changes in gene expression and metabolism. To study the impact of Ca2+-modulated 'ON' and 'OFF' reactions in mammalian cells, pharmacological tools and 'caged' compounds are commonly used under various experimental conditions. The use of these reagents for precise control of Ca2+ signals, nonetheless, is impeded by lack of reversibility and specificity. The recently developed optogenetic tools, particularly those built upon engineered Ca2+ release-activated Ca2+ (CRAC) channels, provide exciting opportunities to remotely and non-invasively modulate Ca2+ signaling due to their superior spatiotemporal resolution and rapid reversibility. In this review, we briefly summarize the latest advances in the development of optogenetic tools (collectively termed as 'genetically encoded Ca2+ actuators', or GECAs) that are tailored for the interrogation of Ca2+ signaling, as well as their applications in remote neuromodulation and optogenetic immunomodulation. Our goal is to provide a general guide to choosing appropriate GECAs for optical control of Ca2+ signaling in cellulo, and in parallel, to stimulate further thoughts on evolving non-opsin-based optogenetics into a fully fledged technology for the study of Ca2+-dependent activities in vivo.
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Affiliation(s)
- Guolin Ma
- Center for Translational Cancer Research, Institute of Biosciences and Technology Texas A&M University, Houston, TX 77030, USA
| | - Shufan Wen
- Center for Translational Cancer Research, Institute of Biosciences and Technology Texas A&M University, Houston, TX 77030, USA
| | - Lian He
- Center for Translational Cancer Research, Institute of Biosciences and Technology Texas A&M University, Houston, TX 77030, USA
| | - Yun Huang
- Center for Epigenetics and Disease Prevention, Institute of Biosciences and Technology, Texas A&M University, Houston, TX 77030, USA; Department of Molecular and Cellular Medicine, College of Medicine, Texas A&M University, Bryan, TX 77807, USA
| | - Youjun Wang
- Beijing Key Laboratory of Gene Resource and Molecular Development, College of Life Sciences, Beijing Normal University, Beijing 100875, China.
| | - Yubin Zhou
- Center for Translational Cancer Research, Institute of Biosciences and Technology Texas A&M University, Houston, TX 77030, USA; Department of Medical Physiology, College of Medicine Texas A&M University, Temple, TX 76504, USA, USA.
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25
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Subedi KP, Ong HL, Ambudkar IS. Assembly of ER-PM Junctions: A Critical Determinant in the Regulation of SOCE and TRPC1. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2017; 981:253-276. [PMID: 29594865 DOI: 10.1007/978-3-319-55858-5_11] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Store-operated calcium entry (SOCE), a unique plasma membrane Ca2+ entry mechanism, is activated when ER-[Ca2+] is decreased. SOCE is mediated via the primary channel, Orai1, as well as others such as TRPC1. STIM1 and STIM2 are ER-Ca2+ sensor proteins that regulate Orai1 and TRPC1. SOCE requires assembly of STIM proteins with the plasma membrane channels which occurs within distinct regions in the cell that have been termed as endoplasmic reticulum (ER)-plasma membrane (PM) junctions. The PM and ER are in close proximity to each other within this region, which allows STIM1 in the ER to interact with and activate either Orai1 or TRPC1 in the plasma membrane. Activation and regulation of SOCE involves dynamic assembly of various components that are involved in mediating Ca2+ entry as well as those that determine the formation and stabilization of the junctions. These components include proteins in the cytosol, ER and PM, as well as lipids in the PM. Recent studies have also suggested that SOCE and its components are compartmentalized within ER-PM junctions and that this process might require remodeling of the plasma membrane lipids and reorganization of structural and scaffolding proteins. Such compartmentalization leads to the generation of spatially- and temporally-controlled Ca2+signals that are critical for regulating many downstream cellular functions.
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Affiliation(s)
- Krishna P Subedi
- Secretory Physiology Section, Molecular Physiology and Therapeutics Branch, NIDCR, NIH, Bethesda, MD, USA
| | - Hwei Ling Ong
- Secretory Physiology Section, Molecular Physiology and Therapeutics Branch, NIDCR, NIH, Bethesda, MD, USA
| | - Indu S Ambudkar
- Secretory Physiology Section, Molecular Physiology and Therapeutics Branch, NIDCR, NIH, Bethesda, MD, USA.
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Gudlur A, Hogan PG. The STIM-Orai Pathway: Orai, the Pore-Forming Subunit of the CRAC Channel. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2017; 993:39-57. [PMID: 28900908 DOI: 10.1007/978-3-319-57732-6_3] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
This chapter focuses on the Orai proteins, Orai1-Orai3, with special emphasis on Orai1, in humans and other mammals, and on the definitive evidence that Orai is the pore subunit of the CRAC channel. It begins by reviewing briefly the defining characteristics of the CRAC channel, then discusses the studies that implicated Orai as part of the store-operated Ca2+ entry pathway and as the CRAC channel pore subunit, and finally examines ongoing work that is providing insights into CRAC channel structure and gating.
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Affiliation(s)
- Aparna Gudlur
- Division of Signalling and Gene Expression, La Jolla Institute for Allergy and Immunology, 9420 Athena Circle, La Jolla, CA, USA.
| | - Patrick G Hogan
- Division of Signalling and Gene Expression, La Jolla Institute for Allergy and Immunology, 9420 Athena Circle, La Jolla, CA, USA.
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Abstract
Aberrant Ca(2+) release-activated Ca(2+) (CRAC) channel activity has been implicated in a number of human disorders, including immunodeficiency, autoimmunity, occlusive vascular diseases and cancer, thus placing CRAC channels among the important targets for the treatment of these disorders. We briefly summarize herein the molecular basis and activation mechanism of CRAC channel and focus on discussing several pharmacological inhibitors of CRAC channels with respect to their biological activity, mechanisms of action and selectivity over other types of Ca(2+) channel in different types of cells.
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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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Xie J, Pan H, Yao J, Zhou Y, Han W. SOCE and cancer: Recent progress and new perspectives. Int J Cancer 2015; 138:2067-77. [PMID: 26355642 PMCID: PMC4764496 DOI: 10.1002/ijc.29840] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2015] [Accepted: 09/03/2015] [Indexed: 12/15/2022]
Abstract
Ca2+ acts as a universal and versatile second messenger in the regulation of a myriad of biological processes, including cell proliferation, differentiation, migration and apoptosis. Store‐operated Ca2+ entry (SOCE) mediated by ORAI and the stromal interaction molecule (STIM) constitutes one of the major routes of calcium entry in nonexcitable cells, in which the depletion of intracellular Ca2+ stores triggers activation of the endoplasmic reticulum (ER)‐resident Ca2+ sensor protein STIM to gate and open the ORAI Ca2+ channels in the plasma membrane (PM). Accumulating evidence indicates that SOCE plays critical roles in cancer cell proliferation, metastasis and tumor neovascularization, as well as in antitumor immunity. We summarize herein the recent advances in our understanding of the function of SOCE in various types of tumor cells, vascular endothelial cells and cells of the immune system. Finally, the therapeutic potential of SOCE inhibitors in the treatment of cancer is also discussed.
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Affiliation(s)
- Jiansheng Xie
- Laboratory of Cancer Biology, Institute of Clinical Science, Sir Run Run Shaw Hospital, College of Medicine, Zhejiang University, Hangzhou, Zhejiang, China
| | - Hongming Pan
- Laboratory of Cancer Biology, Institute of Clinical Science, Sir Run Run Shaw Hospital, College of Medicine, Zhejiang University, Hangzhou, Zhejiang, China.,Department of Medical Oncology, Sir Run Run Shaw Hospital, College of Medicine, Zhejiang University, Hangzhou, Zhejiang, China
| | - Junlin Yao
- Department of Medical Oncology, Sir Run Run Shaw Hospital, College of Medicine, Zhejiang University, Hangzhou, Zhejiang, China
| | - Yubin Zhou
- Center for Translational Cancer Research, Institute of Biosciences and Technology, Texas A&M University Health Science Center, Houston, TX
| | - Weidong Han
- Laboratory of Cancer Biology, Institute of Clinical Science, Sir Run Run Shaw Hospital, College of Medicine, Zhejiang University, Hangzhou, Zhejiang, China.,Department of Medical Oncology, Sir Run Run Shaw Hospital, College of Medicine, Zhejiang University, Hangzhou, Zhejiang, China
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Lin H, Zheng C, Li J, Yang C, Hu L. Ca2+ -activated K+ channel-3.1 blocker TRAM-34 alleviates murine allergic rhinitis. Int Immunopharmacol 2015; 23:642-8. [PMID: 25466273 DOI: 10.1016/j.intimp.2014.10.017] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2014] [Revised: 09/21/2014] [Accepted: 10/17/2014] [Indexed: 01/08/2023]
Abstract
The precise pathogenesis of allergic rhinitis (AR) remains unclear and AR is less easily cured. Recent evidence has suggested that calcium-activated K+ channel-3.1(KCa3.1) is implicated in the immune response of allergic and inflammatory diseases and TRAM-34 is a selective KCa3.1 blocker. However, little is known about its role in AR. We aimed to investigate the effect of TRAM-34 in a mouse model of AR induced by ovalbumin (OVA). The BALB/c mice were divided into six groups: untreated AR group, 200 μg TRAM-34 treated AR group, 400 μg TRAM-34 treated AR group, 200 μg TRAM-34 treated normal group, 400 μg TRAM-34 treated normal group and untreated normal control group. Histopathological characteristics were assessed by HE staining. KCa3.1 protein expression was investigated by immunohistochemistry and western blotting method, and mRNA expression of KCa3.1, stromal interaction molecule1 (STIM1) and Orai1 in nasal tissues were assessed by real-time PCR. Furthermore, concentrations of OVA-specific IgE, ECP, IL-4, IL-5, IL-17 and IL-1β in nasal lavage fluid (NLF) were analyzed by enzyme-linked immunosorbent assay (ELISA). Results showed that TRAM-34 administration into the nostril attenuated sneezing, nasal rubbing, epithelial cell proliferation, eosinophil infiltration and inhibited nasal mucosa KCa3.1, STIM1 and Orai1 expression in TRAM-34 treated mice compared with untreated AR mice and suppressed inflammatory cytokines in the NLF of TRAM-34 treated groups compared with untreated AR mice. In conclusion, TRAM-34 could effectively alleviate murine allergic rhinitis by suppressing KCa3.1 and leads to reduction of K+ efflux and Ca2 + influx, leading to inflammation reduction and allergic responses attenuation.
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31
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Store-operated calcium entry: Mechanisms and modulation. Biochem Biophys Res Commun 2015; 460:40-9. [PMID: 25998732 DOI: 10.1016/j.bbrc.2015.02.110] [Citation(s) in RCA: 152] [Impact Index Per Article: 16.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2015] [Accepted: 02/20/2015] [Indexed: 11/22/2022]
Abstract
Store-operated calcium entry is a central mechanism in cellular calcium signalling and in maintaining cellular calcium balance. This review traces the history of research on store-operated calcium entry, the discovery of STIM and ORAI as central players in calcium entry, and the role of STIM and ORAI in biology and human disease. It describes current knowledge of the basic mechanism of STIM-ORAI signalling and of the varied mechanisms by which STIM-ORAI signalling can be modulated.
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32
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Ma G, Wei M, He L, Liu C, Wu B, Zhang SL, Jing J, Liang X, Senes A, Tan P, Li S, Sun A, Bi Y, Zhong L, Si H, Shen Y, Li M, Lee MS, Zhou W, Wang J, Wang Y, Zhou Y. Inside-out Ca(2+) signalling prompted by STIM1 conformational switch. Nat Commun 2015; 6:7826. [PMID: 26184105 PMCID: PMC4509486 DOI: 10.1038/ncomms8826] [Citation(s) in RCA: 147] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2014] [Accepted: 06/16/2015] [Indexed: 12/11/2022] Open
Abstract
Store-operated Ca(2+) entry mediated by STIM1 and ORAI1 constitutes one of the major Ca(2+) entry routes in mammalian cells. The molecular choreography of STIM1-ORAI1 coupling is initiated by endoplasmic reticulum (ER) Ca(2+) store depletion with subsequent oligomerization of the STIM1 ER-luminal domain, followed by its redistribution towards the plasma membrane to gate ORAI1 channels. The mechanistic underpinnings of this inside-out Ca(2+) signalling were largely undefined. By taking advantage of a unique gain-of-function mutation within the STIM1 transmembrane domain (STIM1-TM), here we show that local rearrangement, rather than alteration in the oligomeric state of STIM1-TM, prompts conformational changes in the cytosolic juxtamembrane coiled-coil region. Importantly, we further identify critical residues within the cytoplasmic domain of STIM1 (STIM1-CT) that entail autoinhibition. On the basis of these findings, we propose a model in which STIM1-TM reorganization switches STIM1-CT into an extended conformation, thereby projecting the ORAI-activating domain to gate ORAI1 channels.
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Affiliation(s)
- Guolin Ma
- Institute of Biosciences and Technology, Texas A&M University Health Science Center, Houston, Texas 77030, USA
| | - Ming Wei
- Beijing Key Laboratory of Gene Resource and Molecular Development, College of Life Sciences, Beijing Normal University, Beijing 100875, China
| | - Lian He
- Institute of Biosciences and Technology, Texas A&M University Health Science Center, Houston, Texas 77030, USA
| | - Chongxu Liu
- High Magnetic Field Laboratory, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei 230031, China
- University of Science and Technology of China, Hefei, Anhui 230036, China
| | - Bo Wu
- High Magnetic Field Laboratory, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei 230031, China
| | - Shenyuan L. Zhang
- Department of Medical Physiology, College of Medicine, Texas A&M University Health Science Center, Temple, Texas 76504, USA
| | - Ji Jing
- Institute of Biosciences and Technology, Texas A&M University Health Science Center, Houston, Texas 77030, USA
| | - Xiaowen Liang
- Institute of Biosciences and Technology, Texas A&M University Health Science Center, Houston, Texas 77030, USA
| | - Alessandro Senes
- Department of Biochemistry, University of Wisconsin Madison, Madison, Wisconsin 53706, USA
| | - Peng Tan
- Institute of Biosciences and Technology, Texas A&M University Health Science Center, Houston, Texas 77030, USA
| | - Siwei Li
- College of Life Sciences, Nankai University, Tianjin 300071, China
| | - Aomin Sun
- Beijing Key Laboratory of Gene Resource and Molecular Development, College of Life Sciences, Beijing Normal University, Beijing 100875, China
| | - Yunchen Bi
- High Magnetic Field Laboratory, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei 230031, China
| | - Ling Zhong
- Institute of Biosciences and Technology, Texas A&M University Health Science Center, Houston, Texas 77030, USA
| | - Hongjiang Si
- Department of Medical Physiology, College of Medicine, Texas A&M University Health Science Center, Temple, Texas 76504, USA
| | - Yuequan Shen
- College of Life Sciences, Nankai University, Tianjin 300071, China
| | - Minyong Li
- Key Laboratory of Chemical Biology, School of Pharmacy, Shandong University, Jinan, Shandong 250012, China
| | - Mi-Sun Lee
- Department of Pediatrics and Communicable Diseases, University of Michigan Medical School, Ann Arbor, Michigan 48109, USA
| | - Weibin Zhou
- Department of Pediatrics and Communicable Diseases, University of Michigan Medical School, Ann Arbor, Michigan 48109, USA
| | - Junfeng Wang
- High Magnetic Field Laboratory, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei 230031, China
- University of Science and Technology of China, Hefei, Anhui 230036, China
| | - Youjun Wang
- Beijing Key Laboratory of Gene Resource and Molecular Development, College of Life Sciences, Beijing Normal University, Beijing 100875, China
| | - Yubin Zhou
- Institute of Biosciences and Technology, Texas A&M University Health Science Center, Houston, Texas 77030, USA
- Department of Medical Physiology, College of Medicine, Texas A&M University Health Science Center, Temple, Texas 76504, USA
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Abstract
The regulatory protein STIM1 controls gating of the Ca(2+) channel ORAI1 by a direct protein-protein interaction. Because STIM1 is anchored in the ER membrane and ORAI1 is in the plasma membrane, the STIM-ORAI pathway can support Ca(2+) influx only where the two membranes come into close apposition, effectively demarcating a microdomain for Ca(2+) signalling. This review begins with a brief summary of the STIM-ORAI pathway of store-operated Ca(2+) influx, then turns to the special geometry of the STIM-ORAI microdomain and the expected characteristics of the microdomain Ca(2+) signal. A final section of the review seeks to place the STIM-ORAI microdomain into a broader context of cellular Ca(2+) signalling.
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Affiliation(s)
- Patrick G Hogan
- La Jolla Institute for Allergy & Immunology, La Jolla, CA 92037, USA.
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34
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Critical role for Orai1 C-terminal domain and TM4 in CRAC channel gating. Cell Res 2015; 25:963-80. [PMID: 26138675 DOI: 10.1038/cr.2015.80] [Citation(s) in RCA: 68] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2015] [Revised: 03/30/2015] [Accepted: 05/22/2015] [Indexed: 01/12/2023] Open
Abstract
Calcium flux through store-operated calcium entry is a major regulator of intracellular calcium homeostasis and various calcium signaling pathways. Two key components of the store-operated calcium release-activated calcium channel are the Ca(2+)-sensing protein stromal interaction molecule 1 (STIM1) and the channel pore-forming protein Orai1. Following calcium depletion from the endoplasmic reticulum, STIM1 undergoes conformational changes that unmask an Orai1-activating domain called CAD. CAD binds to two sites in Orai1, one in the N terminal and one in the C terminal. Most previous studies suggested that gating is initiated by STIM1 binding at the Orai1 N-terminal site, just proximal to the TM1 pore-lining segment, and that binding at the C terminal simply anchors STIM1 within reach of the N terminal. However, a recent study had challenged this view and suggested that the Orai1 C-terminal region is more than a simple STIM1-anchoring site. In this study, we establish that the Orai1 C-terminal domain plays a direct role in gating. We identify a linker region between TM4 and the C-terminal STIM1-binding segment of Orai1 as a key determinant that couples STIM1 binding to gating. We further find that Proline 245 in TM4 of Orai1 is essential for stabilizing the closed state of the channel. Taken together with previous studies, our results suggest a dual-trigger mechanism of Orai1 activation in which binding of STIM1 at the N- and C-terminal domains of Orai1 induces rearrangements in proximal membrane segments to open the channel.
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35
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Onopiuk M, Brutkowski W, Young C, Krasowska E, Róg J, Ritso M, Wojciechowska S, Arkle S, Zabłocki K, Górecki DC. Store-operated calcium entry contributes to abnormal Ca²⁺ signalling in dystrophic mdx mouse myoblasts. Arch Biochem Biophys 2015; 569:1-9. [PMID: 25659883 DOI: 10.1016/j.abb.2015.01.025] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2014] [Revised: 01/20/2015] [Accepted: 01/28/2015] [Indexed: 01/13/2023]
Abstract
Sarcolemma damage and activation of various calcium channels are implicated in altered Ca(2+) homeostasis in muscle fibres of both Duchenne muscular dystrophy (DMD) sufferers and in the mdx mouse model of DMD. Previously we have demonstrated that also in mdx myoblasts extracellular nucleotides trigger elevated cytoplasmic Ca(2+) concentrations due to alterations of both ionotropic and metabotropic purinergic receptors. Here we extend these findings to show that the mdx mutation is associated with enhanced store-operated calcium entry (SOCE). Substantially increased rate of SOCE in mdx myoblasts in comparison to that in control cells correlated with significantly elevated STIM1 protein levels. These results reveal that mutation in the dystrophin-encoding Dmd gene may significantly impact cellular calcium response to metabotropic stimulation involving depletion of the intracellular calcium stores followed by activation of the store-operated calcium entry, as early as in undifferentiated myoblasts. These data are in agreement with the increasing number of reports showing that the dystrophic pathology resulting from dystrophin mutations may be developmentally regulated. Moreover, our results showing that aberrant responses to extracellular stimuli may contribute to DMD pathogenesis suggest that treatments inhibiting such responses might alter progression of this lethal disease.
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Affiliation(s)
- Marta Onopiuk
- Nencki Institute of Experimental Biology, Warsaw, Poland; Departments of Cell Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA(1)
| | - Wojciech Brutkowski
- School of Pharmacy and Biomedical Sciences, University of Portsmouth, Portsmouth, UK; Nencki Institute of Experimental Biology, Warsaw, Poland
| | - Christopher Young
- School of Pharmacy and Biomedical Sciences, University of Portsmouth, Portsmouth, UK
| | - Elżbieta Krasowska
- School of Pharmacy and Biomedical Sciences, University of Portsmouth, Portsmouth, UK; Nencki Institute of Experimental Biology, Warsaw, Poland
| | - Justyna Róg
- Nencki Institute of Experimental Biology, Warsaw, Poland
| | - Morten Ritso
- Institute of Genetic Medicine, Newcastle University, Newcastle Upon Tyne, UK
| | | | - Stephen Arkle
- School of Pharmacy and Biomedical Sciences, University of Portsmouth, Portsmouth, UK
| | | | - Dariusz C Górecki
- School of Pharmacy and Biomedical Sciences, University of Portsmouth, Portsmouth, UK
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36
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Hendron E, Wang X, Zhou Y, Cai X, Goto JI, Mikoshiba K, Baba Y, Kurosaki T, Wang Y, Gill DL. Potent functional uncoupling between STIM1 and Orai1 by dimeric 2-aminodiphenyl borinate analogs. Cell Calcium 2014; 56:482-92. [PMID: 25459299 DOI: 10.1016/j.ceca.2014.10.005] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2014] [Revised: 10/10/2014] [Accepted: 10/14/2014] [Indexed: 12/21/2022]
Abstract
The coupling of ER Ca(2+)-sensing STIM proteins and PM Orai Ca(2+) entry channels generates "store-operated" Ca(2+) signals crucial in controlling responses in many cell types. The dimeric derivative of 2-aminoethoxydiphenyl borinate (2-APB), DPB162-AE, blocks functional coupling between STIM1 and Orai1 with an IC50 (200 nM) 100-fold lower than 2-APB. Unlike 2-APB, DPB162-AE does not affect L-type or TRPC channels or Ca(2+) pumps at maximal STIM1-Orai1 blocking levels. DPB162-AE blocks STIM1-induced Orai1 or Orai2, but does not block Orai3 or STIM2-mediated effects. We narrowed the DPB162-AE site of action to the STIM-Orai activating region (SOAR) of STIM1. DPB162-AE does not prevent the SOAR-Orai1 interaction but potently blocks SOAR-mediated Orai1 channel activation, yet its action is not as an Orai1 channel pore blocker. Using the SOAR-F394H mutant which prevents both physical and functional coupling to Orai1, we reveal DPB162-AE rapidly restores SOAR-Orai binding but only slowly restores Orai1 channel-mediated Ca(2+) entry. With the same SOAR mutant, 2-APB induces rapid physical and functional coupling to Orai1, but channel activation is transient. We infer that the actions of both 2-APB and DPB162-AE are directed toward the STIM1-Orai1 coupling interface. Compared to 2-APB, DPB162-AE is a much more potent and specific STIM1/Orai1 functional uncoupler. DPB162-AE provides an important pharmacological tool and a useful mechanistic probe for the function and coupling between STIM1 and Orai1 channels.
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Affiliation(s)
- Eunan Hendron
- Department of Biochemistry, Temple University School of Medicine, Philadelphia, PA 19140, United States
| | - Xizhuo Wang
- Department of Biochemistry, Temple University School of Medicine, Philadelphia, PA 19140, United States; Department of Cellular and Molecular Physiology, The Pennsylvania State University College of Medicine, Hershey, PA 17033, United States
| | - Yandong Zhou
- Department of Cellular and Molecular Physiology, The Pennsylvania State University College of Medicine, Hershey, PA 17033, United States
| | - Xiangyu Cai
- Department of Cellular and Molecular Physiology, The Pennsylvania State University College of Medicine, Hershey, PA 17033, United States
| | - Jun-ichi Goto
- Department of Physiology, Yamagata University School of Medicine, Yamagata 990-9585, Japan
| | - Katsuhiko Mikoshiba
- Laboratory for Developmental Neurobiology, RIKEN Brain Science Institute, Saitama 351-0198, Japan
| | - Yoshihiro Baba
- Laboratory for Lymphocyte Differentiation, WPI Immunology Frontier Research Center, Osaka University, Suita, Osaka 565-0871, Japan; Laboratory for Lymphocyte Differentiation, RIKEN Center for Integrative Medical Sciences, Yokohama, Kanagawa 230-0045, Japan
| | - Tomohiro Kurosaki
- Laboratory for Lymphocyte Differentiation, WPI Immunology Frontier Research Center, Osaka University, Suita, Osaka 565-0871, Japan; Laboratory for Lymphocyte Differentiation, RIKEN Center for Integrative Medical Sciences, Yokohama, Kanagawa 230-0045, Japan
| | - 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, United States.
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Gudlur A, Quintana A, Zhou Y, Hirve N, Mahapatra S, Hogan PG. STIM1 triggers a gating rearrangement at the extracellular mouth of the ORAI1 channel. Nat Commun 2014; 5:5164. [PMID: 25296861 PMCID: PMC4376667 DOI: 10.1038/ncomms6164] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2014] [Accepted: 09/04/2014] [Indexed: 01/28/2023] Open
Abstract
The ER-resident regulatory protein STIM1 triggers store-operated Ca2+ entry by direct interaction with the plasma membrane Ca2+ channel ORAI1. The mechanism of channel gating remains undefined. Here we establish that STIM1 gates the purified recombinant ORAI1 channel in vitro, and use Tb3+ luminescence and, separately, disulfide crosslinking to probe movements of the pore-lining helices. We show that interaction of STIM1 with the cytoplasmic face of the human ORAI1 channel elicits a conformational change near the external entrance to the pore, detectable at the pore Ca2+-binding residue E106 and the adjacent pore-lining residue V102. We demonstrate that a short nonpolar segment of the pore including V102 forms a barrier to ion flux in the closed channel, implicating the STIM1-dependent movement in channel gating. Our data explain the close coupling between ORAI1 channel gating and ion selectivity, and open a new avenue to dissect the gating, modulation, and inactivation of ORAI-family channels.
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Affiliation(s)
- Aparna Gudlur
- Division of Signalling and Gene Expression, La Jolla Institute for Allergy and Immunology, La Jolla, California 92037, USA
| | - Ariel Quintana
- Division of Signalling and Gene Expression, La Jolla Institute for Allergy and Immunology, La Jolla, California 92037, USA
| | - Yubin Zhou
- Division of Signalling and Gene Expression, La Jolla Institute for Allergy and Immunology, La Jolla, California 92037, USA
| | - Nupura Hirve
- Division of Signalling and Gene Expression, La Jolla Institute for Allergy and Immunology, La Jolla, California 92037, USA
| | - Sahasransu Mahapatra
- Division of Signalling and Gene Expression, La Jolla Institute for Allergy and Immunology, La Jolla, California 92037, USA
| | - Patrick G Hogan
- Division of Signalling and Gene Expression, La Jolla Institute for Allergy and Immunology, La Jolla, California 92037, USA
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Dong H, Klein ML, Fiorin G. Counterion-Assisted Cation Transport in a Biological Calcium Channel. J Phys Chem B 2014; 118:9668-76. [DOI: 10.1021/jp5059897] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Affiliation(s)
- Hao Dong
- Institute for Computational
Molecular Science, Temple University, Philadelphia, Pennsylvania 19122, United States
| | - Michael L. Klein
- Institute for Computational
Molecular Science, Temple University, Philadelphia, Pennsylvania 19122, United States
| | - Giacomo Fiorin
- Institute for Computational
Molecular Science, Temple University, Philadelphia, Pennsylvania 19122, United States
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Schmitz F. Presynaptic [Ca(2+)] and GCAPs: aspects on the structure and function of photoreceptor ribbon synapses. Front Mol Neurosci 2014; 7:3. [PMID: 24567702 PMCID: PMC3915146 DOI: 10.3389/fnmol.2014.00003] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2013] [Accepted: 01/15/2014] [Indexed: 12/21/2022] Open
Abstract
Changes in intracellular calcium ions [Ca2+] play important roles in photoreceptor signaling. Consequently, intracellular [Ca2+] levels need to be tightly controlled. In the light-sensitive outer segments (OS) of photoreceptors, Ca2+ regulates the activity of retinal guanylate cyclases thus playing a central role in phototransduction and light-adaptation by restoring light-induced decreases in cGMP. In the synaptic terminals, changes of intracellular Ca2+ trigger various aspects of neurotransmission. Photoreceptors employ tonically active ribbon synapses that encode light-induced, graded changes of membrane potential into modulation of continuous synaptic vesicle exocytosis. The active zones of ribbon synapses contain large electron-dense structures, synaptic ribbons, that are associated with large numbers of synaptic vesicles. Synaptic coding at ribbon synapses differs from synaptic coding at conventional (phasic) synapses. Recent studies revealed new insights how synaptic ribbons are involved in this process. This review focuses on the regulation of [Ca2+] in presynaptic photoreceptor terminals and on the function of a particular Ca2+-regulated protein, the neuronal calcium sensor protein GCAP2 (guanylate cyclase-activating protein-2) in the photoreceptor ribbon synapse. GCAP2, an EF-hand-containing protein plays multiple roles in the OS and in the photoreceptor synapse. In the OS, GCAP2 works as a Ca2+-sensor within a Ca2+-regulated feedback loop that adjusts cGMP levels. In the photoreceptor synapse, GCAP2 binds to RIBEYE, a component of synaptic ribbons, and mediates Ca2+-dependent plasticity at that site. Possible mechanisms are discussed.
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Affiliation(s)
- Frank Schmitz
- Department of Neuroanatomy, Institute for Anatomy and Cell Biology, Medical School Homburg/Saar, Saarland University Saarland, Germany
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Abstract
Ca(2+) influx via store-operated Ca(2+) release activated Ca(2+) (CRAC) channels represents a main signaling pathway for T-cell activation as well as mast-cell degranulation. 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. Their identification, but even more the recent structural resolution of both proteins by X-ray crystallography has substantially advanced the understanding of the activation mechanism of CRAC channels. In this review, we provide a detailed description of the STIM1/Orai1 signaling pathway thereby focusing on the critical domains mediating both, intra- as well as intermolecular interactions and on the ion permeation pathway. Based on the results of functional studies as well as the recently published crystal structures, we portray a mechanistic view of the steps in the CRAC channel signaling cascade ranging from STIM1 oligomerization over STIM1-Orai1 coupling to the ultimate Orai1 channel activation and permeation.
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Affiliation(s)
- Marc Fahrner
- Institute of Biophysics; Johannes Kepler University Linz; Linz, Austria
| | - Isabella Derler
- Institute of Biophysics; Johannes Kepler University Linz; Linz, Austria
| | - Isaac Jardin
- Institute of Biophysics; Johannes Kepler University Linz; Linz, Austria
| | - Christoph Romanin
- Institute of Biophysics; Johannes Kepler University Linz; Linz, Austria
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