1
|
Gutierrez-Merino C. Brain Hydrophobic Peptides Antagonists of Neurotoxic Amyloid β Peptide Monomers/Oligomers-Protein Interactions. Int J Mol Sci 2023; 24:13846. [PMID: 37762148 PMCID: PMC10531495 DOI: 10.3390/ijms241813846] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2023] [Revised: 09/02/2023] [Accepted: 09/05/2023] [Indexed: 09/29/2023] Open
Abstract
Amyloid β (Aβ) oligomers have been linked to Alzheimer's disease (AD) pathogenesis and are the main neurotoxic forms of Aβ. This review focuses on the following: (i) the Aβ(1-42):calmodulin interface as a model for the design of antagonist Aβ peptides and its limitations; (ii) proteolytic degradation as the major source of highly hydrophobic peptides in brain cells; and (iii) brain peptides that have been experimentally demonstrated to bind to Aβ monomers or oligomers, Aβ fibrils, or Aβ plaques. It is highlighted that the hydrophobic amino acid residues of the COOH-terminal segment of Aβ(1-42) play a key role in its interaction with intracellular protein partners linked to its neurotoxicity. The major source of highly hydrophobic endogenous peptides of 8-10 amino acids in neurons is the proteasome activity. Many canonical antigen peptides bound to the major histocompatibility complex class 1 are of this type. These highly hydrophobic peptides bind to Aβ and are likely to be efficient antagonists of the binding of Aβ monomers/oligomers concentrations in the nanomolar range with intracellular proteins. Also, their complexation with Aβ will protect them against endopeptidases, suggesting a putative chaperon-like physiological function for Aβ that has been overlooked until now. Remarkably, the hydrophobic amino acid residues of Aβ responsible for the binding of several neuropeptides partially overlap with those playing a key role in its interaction with intracellular protein partners that mediates its neurotoxicity. Therefore, these latter neuropeptides are also potential candidates to antagonize Aβ peptides binding to target proteins. In conclusion, the analysis performed in this review points out that hydrophobic endogenous brain neuropeptides could be valuable biomarkers to evaluate the risk of the onset of sporadic AD, as well as for the prognosis of AD.
Collapse
Affiliation(s)
- Carlos Gutierrez-Merino
- Instituto de Biomarcadores de Patologías Moleculares, Universidad de Extremadura, 06006 Badajoz, Spain
| |
Collapse
|
2
|
Shapovalov G, Gordienko D, Prevarskaya N. Store operated calcium channels in cancer progression. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2021; 363:123-168. [PMID: 34392928 DOI: 10.1016/bs.ircmb.2021.02.016] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
In recent decades cancer emerged as one of the leading causes of death in the developed countries, with some types of cancer contributing to the top 10 causes of death on the list of the World Health Organization. Carcinogenesis, a malignant transformation causing formation of tumors in normal tissues, is associated with changes in the cell cycle caused by suppression of signaling pathways leading to cell death and facilitation of those enhancing proliferation. Further progression of cancer, during which benign tumors acquire more aggressive phenotypes, is characterized by metastatic dissemination through the body driven by augmented motility and invasiveness of cancer cells. All these processes are associated with alterations in calcium homeostasis in cancer cells, which promote their proliferation, motility and invasion, and dissuade cell death or cell cycle arrest. Remodeling of store-operated calcium entry (SOCE), one of the major pathways regulating intracellular Ca2+ concentration ([Ca2+]i), manifests a key event in many of these processes. This review systematizes current knowledge on the mechanisms recruiting SOCE-related proteins in carcinogenesis and cancer progression.
Collapse
Affiliation(s)
- George Shapovalov
- Laboratory of Cell Physiology, INSERM U1003, Laboratory of Excellence Ion Channels Science and Therapeutics, Department of Biology, Faculty of Science and Technologiesa, University of Lille, Villeneuve d'Ascq, France.
| | - Dmitri Gordienko
- Laboratory of Cell Physiology, INSERM U1003, Laboratory of Excellence Ion Channels Science and Therapeutics, Department of Biology, Faculty of Science and Technologiesa, University of Lille, Villeneuve d'Ascq, France
| | - Natalia Prevarskaya
- Laboratory of Cell Physiology, INSERM U1003, Laboratory of Excellence Ion Channels Science and Therapeutics, Department of Biology, Faculty of Science and Technologiesa, University of Lille, Villeneuve d'Ascq, France
| |
Collapse
|
3
|
Chen M, Betzer O, Fan Y, Gao Y, Shen M, Sadan T, Popovtzer R, Shi X. Multifunctional Dendrimer-Entrapped Gold Nanoparticles for Labeling and Tracking T Cells Via Dual-Modal Computed Tomography and Fluorescence Imaging. Biomacromolecules 2020; 21:1587-1595. [PMID: 32154709 DOI: 10.1021/acs.biomac.0c00147] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Nanosystems for monitoring and tracking T cells provide an important basis for evaluating the functionality and efficacy of T cell-based immunotherapy. To this end, we designed herein an efficient nanoprobe for T cell monitoring and tracking using poly(amidoamine) (PAMAM) dendrimer-entrapped gold nanoparticles (Au DENPs) conjugated with Fluo-4 for dual-mode computed tomography (CT) and fluorescence imaging. In this study, PAMAM dendrimers of generation 5 (G5) were modified with hydroxyl-terminated polyethylene glycol (PEG) and then used to entrap 2.0 nm Au NPs followed by acetylation of the excess amine groups on the dendrimer surface. Subsequently, the calcium ion probe was covalently attached to the dendrimer nanohybrids through the PEG hydroxyl end groups to gain the functional {(Au0)25-G5.NHAc-(PEG)14-(Fluo-4)2} nanoprobe. This nanoprobe had excellent water solubility, high X-ray attenuation coefficient, and good cytocompatibility in the given concentration range, as well as a high T cell labeling efficiency. Confocal microscopy and flow cytometry results demonstrated that the nanoprobe was able to fluorescently sense activated T cells. Moreover, the nanoprobe was able to realize both CT and fluorescence imaging of subcutaneously injected T cells in vivo. Thus, the developed novel dendrimer-based nanosystem may hold great promise for advancing and improving the clinical application of T cell-based immunotherapy.
Collapse
Affiliation(s)
- Meixiu Chen
- State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, International Joint Laboratory for Advanced Fiber and Low-dimension Materials, College of Chemistry, Chemical Engineering and Biotechnology, Donghua University, Shanghai 201620, P. R. China
| | - Oshra Betzer
- Faculty of Engineering and the Institute of Nanotechnology & Advanced Materials, Bar-Ilan University, Ramat Gan 5290002, Israel
| | - Yu Fan
- State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, International Joint Laboratory for Advanced Fiber and Low-dimension Materials, College of Chemistry, Chemical Engineering and Biotechnology, Donghua University, Shanghai 201620, P. R. China
| | - Yue Gao
- State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, International Joint Laboratory for Advanced Fiber and Low-dimension Materials, College of Chemistry, Chemical Engineering and Biotechnology, Donghua University, Shanghai 201620, P. R. China
| | - Mingwu Shen
- State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, International Joint Laboratory for Advanced Fiber and Low-dimension Materials, College of Chemistry, Chemical Engineering and Biotechnology, Donghua University, Shanghai 201620, P. R. China
| | - Tamar Sadan
- Faculty of Engineering and the Institute of Nanotechnology & Advanced Materials, Bar-Ilan University, Ramat Gan 5290002, Israel
| | - Rachela Popovtzer
- Faculty of Engineering and the Institute of Nanotechnology & Advanced Materials, Bar-Ilan University, Ramat Gan 5290002, Israel
| | - Xiangyang Shi
- State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, International Joint Laboratory for Advanced Fiber and Low-dimension Materials, College of Chemistry, Chemical Engineering and Biotechnology, Donghua University, Shanghai 201620, P. R. China
| |
Collapse
|
4
|
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.
Collapse
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
| |
Collapse
|
5
|
Emrich SM, Yoast RE, Xin P, Zhang X, Pathak T, Nwokonko R, Gueguinou MF, Subedi KP, Zhou Y, Ambudkar IS, Hempel N, Machaca K, Gill DL, Trebak M. Cross-talk between N-terminal and C-terminal domains in stromal interaction molecule 2 (STIM2) determines enhanced STIM2 sensitivity. J Biol Chem 2019; 294:6318-6332. [PMID: 30824535 DOI: 10.1074/jbc.ra118.006801] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2018] [Revised: 02/28/2019] [Indexed: 12/20/2022] Open
Abstract
Store-operated Ca2+ entry (SOCE) is a ubiquitous pathway for Ca2+ influx across the plasma membrane (PM). SOCE is mediated by the endoplasmic reticulum (ER)-associated Ca2+-sensing proteins stromal interaction molecule 1 (STIM1) and STIM2, which transition into an active conformation in response to ER Ca2+ store depletion, thereby interacting with and gating PM-associated ORAI1 channels. Although structurally homologous, STIM1 and STIM2 generate distinct Ca2+ signatures in response to varying strengths of agonist stimulation. The physiological functions of these Ca2+ signatures, particularly under native conditions, remain unclear. To investigate the structural properties distinguishing STIM1 and STIM2 activation of ORAI1 channels under native conditions, here we used CRISPR/Cas9 to generate STIM1-/-, STIM2-/-, and STIM1/2-/- knockouts in HEK293 and colorectal HCT116 cells. We show that depending on cell type, STIM2 can significantly sustain SOCE in response to maximal store depletion. Utilizing the SOCE modifier 2-aminoethoxydiphenyl borate (2-APB), we demonstrate that 2-APB-activated store-independent Ca2+ entry is mediated exclusively by endogenous STIM2. Using variants that either stabilize or disrupt intramolecular interactions of STIM C termini, we show that the increased flexibility of the STIM2 C terminus contributes to its selective store-independent activation by 2-APB. However, STIM1 variants with enhanced flexibility in the C terminus failed to support its store-independent activation. STIM1/STIM2 chimeric constructs indicated that coordination between N-terminal sensitivity and C-terminal flexibility is required for specific store-independent STIM2 activation. Our results clarify the structural determinants underlying activation of specific STIM isoforms, insights that are potentially useful for isoform-selective drug targeting.
Collapse
Affiliation(s)
- Scott M Emrich
- From the Departments of Cellular and Molecular Physiology and
| | - Ryan E Yoast
- From the Departments of Cellular and Molecular Physiology and
| | - Ping Xin
- From the Departments of Cellular and Molecular Physiology and
| | - Xuexin Zhang
- From the Departments of Cellular and Molecular Physiology and
| | | | - Robert Nwokonko
- From the Departments of Cellular and Molecular Physiology and
| | | | - Krishna P Subedi
- the Secretory Physiology Section, NIDCR, National Institutes of Health, Bethesda, Maryland 20892, and
| | - Yandong Zhou
- From the Departments of Cellular and Molecular Physiology and
| | - Indu S Ambudkar
- the Secretory Physiology Section, NIDCR, National Institutes of Health, Bethesda, Maryland 20892, and
| | - Nadine Hempel
- Pharmacology, Pennsylvania State University College of Medicine, Hershey, Pennsylvania 17033
| | - Khaled Machaca
- the Department of Physiology and Biophysics, Weill Cornell Medical College in Qatar, Education City, Qatar Foundation, P.O. Box 24144, Doha, Qatar
| | - Donald L Gill
- From the Departments of Cellular and Molecular Physiology and
| | - Mohamed Trebak
- From the Departments of Cellular and Molecular Physiology and
| |
Collapse
|
6
|
Tuning store-operated calcium entry to modulate Ca 2+-dependent physiological processes. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2018; 1866:1037-1045. [PMID: 30521873 DOI: 10.1016/j.bbamcr.2018.11.018] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/12/2018] [Revised: 11/28/2018] [Accepted: 11/29/2018] [Indexed: 01/10/2023]
Abstract
The intracellular calcium signaling processes are tightly regulated to ensure the generation of calcium signals with the specific spatiotemporal characteristics required for regulating various cell functions. Compartmentalization of the molecular components involved in the generation of these signals at discrete intracellular sites ensures the signaling specificity and transduction fidelity of the signal for regulating downstream effector processes. Store-operated calcium entry (SOCE) is ubiquitously present in cells and is critical for essential cell functions in a variety of tissues. SOCE is mediated via plasma membrane Ca2+ channels that are activated when luminal [Ca2+] of the endoplasmic reticulum ([Ca2+]ER) is decreased. The ER-resident stromal interaction molecules, STIM1 and STIM2, respond to decreases in [Ca2+]ER by undergoing conformational changes that cause them to aggregate at the cell periphery in ER-plasma membrane (ER-PM) junctions. At these sites, STIM proteins recruit Orai1 channels and trigger their activation. Importantly, the two STIM proteins concertedly modulate Orai1 function as well as the sensitivity of SOCE to ER-Ca2+ store depletion. Another family of plasma membrane Ca2+ channels, known as the Transient Receptor Potential Canonical (TRPC) channels (TRPC1-7) also contribute to sustained [Ca2+]i elevation. Although Ca2+ signals generated by these channels overlap with those of Orai1, they regulate distinct functions in the cells. Importantly, STIM1 is also required for plasma membrane localization and activation of some TRPCs. In this review, we will discuss various molecular components and factors that govern the activation, regulation and modulation of the Ca2+ signal generated by Ca2+ entry pathways in response to depletion of ER-Ca2+ stores. This article is part of a Special Issue entitled: ECS Meeting edited by Claus Heizmann, Joachim Krebs and Jacques Haiech.
Collapse
|
7
|
S -Nitrosylation of STIM1 by Neuronal Nitric Oxide Synthase Inhibits Store-Operated Ca 2+ Entry. J Mol Biol 2018; 430:1773-1785. [DOI: 10.1016/j.jmb.2018.04.028] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2017] [Revised: 03/28/2018] [Accepted: 04/19/2018] [Indexed: 11/18/2022]
|
8
|
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
|
9
|
Fahrner M, Stadlbauer M, Muik M, Rathner P, Stathopulos P, Ikura M, Müller N, Romanin C. A dual mechanism promotes switching of the Stormorken STIM1 R304W mutant into the activated state. Nat Commun 2018; 9:825. [PMID: 29483506 PMCID: PMC5827659 DOI: 10.1038/s41467-018-03062-w] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2017] [Accepted: 01/17/2018] [Indexed: 11/22/2022] Open
Abstract
STIM1 and Orai1 are key components of the Ca2+-release activated Ca2+ (CRAC) current. Orai1, which represents the subunit forming the CRAC channel complex, is activated by the ER resident Ca2+ sensor STIM1. The genetically inherited Stormorken syndrome disease has been associated with the STIM1 single point R304W mutant. The resulting constitutive activation of Orai1 mainly involves the CRAC-activating domain CAD/SOAR of STIM1, the exposure of which is regulated by the molecular interplay between three cytosolic STIM1 coiled-coil (CC) domains. Here we present a dual mechanism by which STIM1 R304W attains the pathophysiological, constitutive activity eliciting the Stormorken syndrome. The R304W mutation induces a helical elongation within the CC1 domain, which together with an increased CC1 homomerization, destabilize the resting state of STIM1. This culminates, even in the absence of store depletion, in structural extension and CAD/SOAR exposure of STIM1 R304W leading to constitutive CRAC channel activation and Stormorken disease. Stormorken syndrome is associated with the R304W mutation in STIM1, which is a Calcium sensor in the endoplasmic reticulum. Here authors use FRET and electrophysiology to show that R304W induces STIM1 conformational extension by a dual mechanism resulting in constitutive activation of Ca2+ channels.
Collapse
Affiliation(s)
- Marc Fahrner
- Institute of Biophysics, Johannes Kepler University Linz, Gruberstrasse 40, 4020, Linz, Austria.
| | - Michael Stadlbauer
- Institute of Biophysics, Johannes Kepler University Linz, Gruberstrasse 40, 4020, Linz, Austria
| | - Martin Muik
- Institute of Biophysics, Johannes Kepler University Linz, Gruberstrasse 40, 4020, Linz, Austria
| | - Petr Rathner
- Institute of Organic Chemistry, Johannes Kepler University Linz, Altenbergerstrasse 69, 4040, Linz, Austria
| | - Peter Stathopulos
- Department of Physiology and Pharmacology, University of Western Ontario, London, ON N6A 5C1, Canada
| | - Mitsu Ikura
- Princess Margaret Cancer Center, University Health Network, Toronto, ON M5G 1L7, Canada.,Department of Medical Biophysics, University of Toronto, Toronto, ON M5G 1L7, Canada
| | - Norbert Müller
- Institute of Organic Chemistry, Johannes Kepler University Linz, Altenbergerstrasse 69, 4040, Linz, Austria.,Faculty of Science, University of South Bohemia, Branišovská 1645/31A, 370 05, České Budějovice, Czech Republic
| | - Christoph Romanin
- Institute of Biophysics, Johannes Kepler University Linz, Gruberstrasse 40, 4020, Linz, Austria.
| |
Collapse
|
10
|
Disturbed Ca 2+ Homeostasis in Muscle-Wasting Disorders. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2018; 1088:307-326. [PMID: 30390258 DOI: 10.1007/978-981-13-1435-3_14] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Ca2+ is essential for proper structure and function of skeletal muscle. It not only activates contraction and force development but also participates in multiple signaling pathways. Low levels of Ca2+ restrain muscle regeneration by limiting the fusion of satellite cells. Ironically, sustained elevations of Ca2+ also result in muscle degeneration as this ion promotes high rates of protein breakdown. Moreover, transforming growth factors (TGFs) which are well known for controlling muscle growth also regulate Ca2+ channels. Thus, therapies focused on changing levels of Ca2+ and TGFs are promising for treating muscle-wasting disorders. Three principal systems govern the homeostasis of Ca2+, namely, excitation-contraction (EC) coupling, excitation-coupled Ca2+ entry (ECCE), and store-operated Ca2+ entry (SOCE). Accordingly, alterations in these systems can lead to weakness and atrophy in many hereditary diseases, such as Brody disease, central core disease (CCD), tubular aggregate myopathy (TAM), myotonic dystrophy type 1 (MD1), oculopharyngeal muscular dystrophy (OPMD), and Duchenne muscular dystrophy (DMD). Here, the interrelationship between all these molecules and processes is reviewed.
Collapse
|
11
|
Choi YJ, Zhu J, Chung S, Siddiqui N, Feng Q, Stathopulos PB. Targeting Cysteine Thiols for in Vitro Site-specific Glycosylation of Recombinant Proteins. J Vis Exp 2017. [PMID: 29053695 DOI: 10.3791/56302] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Stromal interaction molecule-1 (STIM1) is a type-I transmembrane protein located on the endoplasmic reticulum (ER) and plasma membranes (PM). ER-resident STIM1 regulates the activity of PM Orai1 channels in a process known as store operated calcium (Ca2+) entry which is the principal Ca2+ signaling process that drives the immune response. STIM1 undergoes post-translational N-glycosylation at two luminal Asn sites within the Ca2+ sensing domain of the molecule. However, the biochemical, biophysical, and structure biological effects of N-glycosylated STIM1 were poorly understood until recently due to an inability to readily obtain high levels of homogeneous N-glycosylated protein. Here, we describe the implementation of an in vitro chemical approach which attaches glucose moieties to specific protein sites applicable to understanding the underlying effects of N-glycosylation on protein structure and mechanism. Using solution nuclear magnetic resonance spectroscopy we assess both efficiency of the modification as well as the structural consequences of the glucose attachment with a single sample. This approach can readily be adapted to study the myriad glycosylated proteins found in nature.
Collapse
Affiliation(s)
- Yoo Jung Choi
- Department of Physiology and Pharmacology, Schulich School of Medicine and Dentistry, University of Western Ontario
| | - Jinhui Zhu
- Department of Physiology and Pharmacology, Schulich School of Medicine and Dentistry, University of Western Ontario
| | - Steve Chung
- Department of Physiology and Pharmacology, Schulich School of Medicine and Dentistry, University of Western Ontario
| | - Naveed Siddiqui
- Department of Physiology and Pharmacology, Schulich School of Medicine and Dentistry, University of Western Ontario
| | - Qingping Feng
- Department of Physiology and Pharmacology, Schulich School of Medicine and Dentistry, University of Western Ontario
| | - Peter B Stathopulos
- Department of Physiology and Pharmacology, Schulich School of Medicine and Dentistry, University of Western Ontario;
| |
Collapse
|
12
|
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.
Collapse
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.
| |
Collapse
|
13
|
From Stores to Sinks: Structural Mechanisms of Cytosolic Calcium Regulation. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2017; 981:215-251. [PMID: 29594864 DOI: 10.1007/978-3-319-55858-5_10] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/08/2022]
Abstract
All eukaryotic cells have adapted the use of the calcium ion (Ca2+) as a universal signaling element through the evolution of a toolkit of Ca2+ sensor, buffer and effector proteins. Among these toolkit components, integral and peripheral proteins decorate biomembranes and coordinate the movement of Ca2+ between compartments, sense these concentration changes and elicit physiological signals. These changes in compartmentalized Ca2+ levels are not mutually exclusive as signals propagate between compartments. For example, agonist induced surface receptor stimulation can lead to transient increases in cytosolic Ca2+ sourced from endoplasmic reticulum (ER) stores; the decrease in ER luminal Ca2+ can subsequently signal the opening surface channels which permit the movement of Ca2+ from the extracellular space to the cytosol. Remarkably, the minuscule compartments of mitochondria can function as significant cytosolic Ca2+ sinks by taking up Ca2+ in a coordinated manner. In non-excitable cells, inositol 1,4,5 trisphosphate receptors (IP3Rs) on the ER respond to surface receptor stimulation; stromal interaction molecules (STIMs) sense the ER luminal Ca2+ depletion and activate surface Orai1 channels; surface Orai1 channels selectively permit the movement of Ca2+ from the extracellular space to the cytosol; uptake of Ca2+ into the matrix through the mitochondrial Ca2+ uniporter (MCU) further shapes the cytosolic Ca2+ levels. Recent structural elucidations of these key Ca2+ toolkit components have improved our understanding of how they function to orchestrate precise cytosolic Ca2+ levels for specific physiological responses. This chapter reviews the atomic-resolution structures of IP3R, STIM1, Orai1 and MCU elucidated by X-ray crystallography, electron microscopy and NMR and discusses the mechanisms underlying their biological functions in their respective compartments within the cell.
Collapse
|
14
|
Ambudkar IS. Calcium signalling in salivary gland physiology and dysfunction. J Physiol 2016; 594:2813-24. [PMID: 26592972 PMCID: PMC4887685 DOI: 10.1113/jp271143] [Citation(s) in RCA: 62] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2015] [Accepted: 10/31/2015] [Indexed: 01/29/2023] Open
Abstract
Studies over the past four decades have established that Ca(2+) is a critical factor in control of salivary gland function and have led to identification of the critical components of this process. The major ion transport mechanisms and ion channels that are involved in fluid secretion have also been established. The key event in activation of fluid secretion is an increase in [Ca(2+) ]i triggered by inositol 1,4,5-trisphosphate (IP3 )-induced release of Ca(2+) from ER via the IP3 receptor (IP3 R). IP3 Rs determine the site of initiation and the pattern of the [Ca(2+) ]i signal in the cell. However, Ca(2+) entry into the cell is required to sustain the elevation of [Ca(2+) ]i and fluid secretion and is mediated by the store-operated Ca(2+) entry (SOCE) mechanism. Orai1, TRPC1, TRPC3 and STIM1 have been identified as critical components of SOCE in these cells. Cells finely tune the generation and amplification of [Ca(2+) ]i signals for regulation of cell function. An important emerging area is the concept that unregulated [Ca(2+) ]i signals in cells can directly cause cell damage, dysfunction and disease. Alternatively, aberrant [Ca(2+) ]i signals can also amplify and increase the rates of cell damage. Such defects in Ca(2+) signalling have been described in salivary glands in conjunction with radiation-induced loss of salivary gland function as well as in the salivary defects associated with the autoimmune exocrinopathy Sjögren's syndrome. Such defects have been associated with altered function or expression of key Ca(2+) signalling components, such as STIM proteins and TRP channels. These studies offer new avenues for examining the mechanisms underlying the disease and development of novel clinical targets and therapeutic strategies.
Collapse
Affiliation(s)
- Indu S Ambudkar
- Secretory Physiology Section, Molecular Physiology and Therapeutics Branch, National Institute of Dental Research, National Institutes of Health, Bethesda, MD, 20892, USA
| |
Collapse
|
15
|
Extracellular Calcium Has Multiple Targets to Control Cell Proliferation. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2016; 898:133-56. [DOI: 10.1007/978-3-319-26974-0_7] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
|
16
|
Lopez JJ, Albarran L, Gómez LJ, Smani T, Salido GM, Rosado JA. Molecular modulators of store-operated calcium entry. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2016; 1863:2037-43. [PMID: 27130253 DOI: 10.1016/j.bbamcr.2016.04.024] [Citation(s) in RCA: 50] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/16/2016] [Revised: 04/13/2016] [Accepted: 04/25/2016] [Indexed: 12/20/2022]
Abstract
Three decades ago, store-operated Ca(2+) entry (SOCE) was identified as a unique mechanism for Ca(2+) entry through plasma membrane (PM) Ca(2+)-permeable channels modulated by the intracellular Ca(2+) stores, mainly the endoplasmic reticulum (ER). Extensive analysis of the communication between the ER and the PM leads to the identification of the protein STIM1 as the ER-Ca(2+) sensor that gates the Ca(2+) channels in the PM. Further analysis on the biophysical, electrophysiological and biochemical properties of STIM1-dependent Ca(2+) channels has revealed the presence of a highly Ca(2+)-selective channel termed Ca(2+) release-activated Ca(2+) channel (CRAC), consisting of Orai1 subunits, and non-selective cation channels named store-operated channels (SOC), including both Orai1 and TRPC channel subunits. Since the identification of the key elements of CRAC and SOC channels a number of intracellular modulators have been reported to play essential roles in the stabilization of STIM-Orai interactions, collaboration with STIM1 conformational changes or mediating slow Ca(2+)-dependent inactivation. Here, we review our current understanding of some of the key modulators of STIM1-Orai1 interaction, including the proteins CRACR2A, STIMATE, SARAF, septins, golli and ORMDL3.
Collapse
Affiliation(s)
- Jose J Lopez
- Department of Physiology (Cell Physiology Research Group), University of Extremadura, 10003 Cáceres, Spain
| | - Letizia Albarran
- Department of Physiology (Cell Physiology Research Group), University of Extremadura, 10003 Cáceres, Spain
| | - Luis J Gómez
- Department of Physiology (Cell Physiology Research Group), University of Extremadura, 10003 Cáceres, Spain
| | - Tarik Smani
- Department of Medical Physiology and Biophysic, Institute of Biomedicine of Sevilla, Sevilla, Spain
| | - Gines M Salido
- Department of Physiology (Cell Physiology Research Group), University of Extremadura, 10003 Cáceres, Spain
| | - Juan A Rosado
- Department of Physiology (Cell Physiology Research Group), University of Extremadura, 10003 Cáceres, Spain.
| |
Collapse
|
17
|
Wen J, Huang YC, Xiu HH, Shan ZM, Xu KQ. Altered expression of stromal interaction molecule (STIM)-calcium release-activated calcium channel protein (ORAI) and inositol 1,4,5-trisphosphate receptors (IP3Rs) in cancer: will they become a new battlefield for oncotherapy? CHINESE JOURNAL OF CANCER 2016; 35:32. [PMID: 27013185 PMCID: PMC4807559 DOI: 10.1186/s40880-016-0094-2] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/17/2015] [Accepted: 03/03/2016] [Indexed: 12/20/2022]
Abstract
The stromal interaction molecule (STIM)-calcium release-activated calcium channel protein (ORAI) and inositol 1,4,5-trisphosphate receptors (IP3Rs) play pivotal roles in the modulation of Ca2+-regulated pathways from gene transcription to cell apoptosis by driving calcium-dependent signaling processes. Increasing evidence has implicated the dysregulation of STIM–ORAI and IP3Rs in tumorigenesis and tumor progression. By controlling the activities, structure, and/or expression levels of these Ca2+-transporting proteins, malignant cancer cells can hijack them to drive essential biological functions for tumor development. However, the molecular mechanisms underlying the participation of STIM–ORAI and IP3Rs in the biological behavior of cancer remain elusive. In this review, we summarize recent advances regarding STIM–ORAI and IP3Rs and discuss how they promote cell proliferation, apoptosis evasion, and cell migration through temporal and spatial rearrangements in certain types of malignant cells. An understanding of the essential roles of STIM–ORAI and IP3Rs may provide new pharmacologic targets that achieve a better therapeutic effect by inhibiting their actions in key intracellular signaling pathways.
Collapse
Affiliation(s)
- Jing Wen
- Department of Anesthesiology, The First Affiliated Hospital, Sun Yat-sen University, Guangzhou, Guangdong, 510080, P. R. China
| | - Ying-Cheng Huang
- Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, Guangdong, 510080, P. R. China
| | - Huan-Huan Xiu
- Department of Anesthesiology, The First Affiliated Hospital, Sun Yat-sen University, Guangzhou, Guangdong, 510080, P. R. China
| | - Zhi-Ming Shan
- Department of Anesthesiology, The First Affiliated Hospital, Sun Yat-sen University, Guangzhou, Guangdong, 510080, P. R. China
| | - Kang-Qing Xu
- Department of Anesthesiology, The First Affiliated Hospital, Sun Yat-sen University, Guangzhou, Guangdong, 510080, P. R. China.
| |
Collapse
|
18
|
Abstract
Ca2+ entry into the cell via store-operated Ca2+ release-activated Ca2+ (CRAC) channels triggers diverse signaling cascades that affect cellular processes like cell growth, gene regulation, secretion, and cell death. These store-operated Ca2+ channels open after depletion of intracellular Ca2+ stores, and their main features are fully reconstituted by the two molecular key players: the stromal interaction molecule (STIM) and Orai. STIM represents an endoplasmic reticulum-located Ca2+ sensor, while Orai forms a highly Ca2+-selective ion channel in the plasma membrane. Functional as well as mutagenesis studies together with structural insights about STIM and Orai proteins provide a molecular picture of the interplay of these two key players in the CRAC signaling cascade. This review focuses on the main experimental advances in the understanding of the STIM1-Orai choreography, thereby establishing a portrait of key mechanistic steps in the CRAC channel signaling cascade. The focus is on the activation of the STIM proteins, the subsequent coupling of STIM1 to Orai1, and the consequent structural rearrangements that gate the Orai channels into the open state to allow Ca2+ permeation into the cell.
Collapse
Affiliation(s)
- Isabella Derler
- Institute of Biophysics, Johannes Kepler University of Linz, Linz, Austria; and
| | - Isaac Jardin
- Department of Physiology, University of Extremadura, Cáceres, Spain
| | - Christoph Romanin
- Institute of Biophysics, Johannes Kepler University of Linz, Linz, Austria; and
| |
Collapse
|
19
|
Shin DM, Son A, Park S, Kim MS, Ahuja M, Muallem S. The TRPCs, Orais and STIMs in ER/PM Junctions. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2016; 898:47-66. [PMID: 27161224 DOI: 10.1007/978-3-319-26974-0_3] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
The Ca(2+) second messenger is initiated at ER/PM junctions and propagates into the cell interior to convey the receptor information. The signal is maintained by Ca(2+) influx across the plasma membrane through the Orai and TRPC channels. These Ca(2+) influx channels form complexes at ER/PM junctions with the ER Ca(2+) sensor STIM1, which activates the channels. The function of STIM1 is modulated by other STIM isoforms like STIM1L, STIM2 and STIM2.1/STIM2β and by SARAF, which mediates the Ca(2+)-dependent inhibition of Orai channels. The ER/PM junctions are formed at membrane contact sites by tethering proteins that generate several types of ER/PM junctions, such as PI(4,5)P2-poor and PI(4,5)P2-rich domains. This chapter discusses several properties of the TRPC channels, the Orai channels and the STIMs, their key interacting proteins and how interaction of the STIMs with the channels gates their activity. The chapter closes by highlighting open questions and potential future directions in this field.
Collapse
Affiliation(s)
- Dong Min Shin
- Department of Oral Biology, BK 21 PLUS Project, Yonsei University College of Dentistry, Seoul, 120-752, South Korea.
| | - Aran Son
- Epithelial Signaling and Transport Section, Molecular Physiology and Therapeutics Branch, National Institute of Dental and Craniofacial Research, National Institute of Health, Bethesda, MD, 20892, USA
| | - Seonghee Park
- Department of Physiology, School of Medicine, EwhaWomans University, 911-1 Mok-6-dong, Yang Chun-gu, Seoul, 158-710, South Korea
| | - Min Seuk Kim
- Department of Oral Physiology, School of Dentistry, Wonkwang University, Iksan City, Jeonbuk, South Korea
| | - Malini Ahuja
- Epithelial Signaling and Transport Section, Molecular Physiology and Therapeutics Branch, National Institute of Dental and Craniofacial Research, National Institute of Health, Bethesda, MD, 20892, USA
| | - Shmuel Muallem
- Epithelial Signaling and Transport Section, Molecular Physiology and Therapeutics Branch, National Institute of Dental and Craniofacial Research, National Institute of Health, Bethesda, MD, 20892, USA.
| |
Collapse
|
20
|
Qi Z, Wang Y, Zhou H, Liang N, Yang L, Liu L, Zhang W. The Central Analgesic Mechanism of YM-58483 in Attenuating Neuropathic Pain in Rats. Cell Mol Neurobiol 2015; 36:1035-43. [PMID: 26514127 DOI: 10.1007/s10571-015-0292-5] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2015] [Accepted: 10/22/2015] [Indexed: 12/18/2022]
Abstract
Calcium channel antagonists are commonly used to treat neuropathic pain. Their analgesic effects rely on inhibiting long-term potentiation, and neurotransmitters release in the spinal cord. Store-operated Ca(2+)channels (SOCCs) are highly Ca(2+)-selective cation channels broadly expressed in non-excitable cells and some excitable cells. Recent studies have shown that the potent inhibitor of SOCCs, YM-58483, has analgesic effects on neuropathic pain, but its mechanism is unclear. This experiment performed on spinal nerve ligation (SNL)-induced neuropathic pain model in rats tries to explore the mechanism, whereby YM-58483 attenuates neuropathic pain. The left L5 was ligated to produce the SNL neuropathic pain model in male Sprague-Dawley rats. The withdrawal threshold of rats was measured by the up-down method and Hargreaves' method before and after intrathecal administration of YM-58483 and vehicle. The SOCCs in the spinal dorsal horn were located by immunofluorescence. The expression of phosphorylated ERK and phosphorylated CREB, CD11b, and GFAP proteins in spinal level was tested by Western blot, while the release of proinflammatory cytokines (IL-1β, TNF-α, PGE2) was measured by enzyme-linked immunosorbent assay (ELISA). Intrathecal YM-58483 at the concentration of 300 μM (1.5 nmol) and 1000 μM (10 nmol) produced a significant central analgesic effect on the SNL rats, compared with control + vehicle (n = 7, P < 0.001). However, both could not prevent the development of neuropathic pain, compared with normal + saline (P < 0.001). Immunofluorescent staining revealed that Orai1 and STIM1 (the two key components of SOCCs) were located in the spinal dorsal horn neurons. Western blot showed that YM-58483 could decrease the levels of P-ERK and P-CREB (n = 10, #P < 0.05), without affecting the expression of CD11b and GFAP (n = 10, #P > 0.05). YM-58483 also inhibited the release of spinal cord IL-1β, TNF-α, and PGE2, compared with control + vehicle (n = 5, #P < 0.001). The analgesic mechanism of YM-58483 may be via inhibiting central ERK/CREB signaling in the neurons and decreasing central IL-1β, TNF-α, and PGE2 release to reduce neuronal excitability in the spinal dorsal horn of the SNL rats.
Collapse
Affiliation(s)
- Zeyou Qi
- Second Xiang-Ya Hospital of Central South University, Changsha, China
| | - Yaping Wang
- Second Xiang-Ya Hospital of Central South University, Changsha, China.
| | - Haocheng Zhou
- Second Xiang-Ya Hospital of Central South University, Changsha, China
| | - Na Liang
- Second Xiang-Ya Hospital of Central South University, Changsha, China
| | - Lin Yang
- Second Xiang-Ya Hospital of Central South University, Changsha, China
| | - Lei Liu
- Second Xiang-Ya Hospital of Central South University, Changsha, China
| | - Wei Zhang
- Second Xiang-Ya Hospital of Central South University, Changsha, China
| |
Collapse
|
21
|
Abstract
Stromal interaction molecules (STIM) 1 and 2 are sensors of the calcium concentration in the endoplasmic reticulum. Depletion of endoplasmic reticulum calcium stores activates STIM proteins which, in turn, bind and open calcium channels in the plasma membrane formed by the proteins ORAI1, ORAI2, and ORAI3. The resulting store-operated calcium entry (SOCE), mostly controlled by the principal components STIM1 and ORAI1, has been particularly characterized in immune cells. In the nervous system, all STIM and ORAI homologs are expressed. This review summarizes current knowledge on distribution and function of STIM and ORAI proteins in central neurons and glial cells, i.e. astrocytes and microglia. STIM2 is required for SOCE in hippocampal synapses and cortical neurons, whereas STIM1 controls calcium store replenishment in cerebellar Purkinje neurons. In microglia, STIM1, STIM2, and ORAI1 regulate migration and phagocytosis. The isoforms ORAI2 and ORAI3 are candidates for SOCE channels in neurons and astrocytes, respectively. Due to the role of SOCE in neuronal and glial calcium homeostasis, dysfunction of STIM and ORAI proteins may have consequences for the development of neurodegenerative disorders, such as Alzheimer's disease.
Collapse
Affiliation(s)
- Robert Kraft
- a Carl-Ludwig-Institute for Physiology, University of Leipzig ; Leipzig , Germany
| |
Collapse
|
22
|
Ca(2+) homeostasis and endoplasmic reticulum (ER) stress: An integrated view of calcium signaling. Biochem Biophys Res Commun 2015; 460:114-21. [PMID: 25998740 DOI: 10.1016/j.bbrc.2015.02.004] [Citation(s) in RCA: 378] [Impact Index Per Article: 42.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2014] [Accepted: 02/02/2015] [Indexed: 12/21/2022]
Abstract
Cellular Ca(2+) homeostasis is maintained through the integrated and coordinated function of Ca(2+) transport molecules, Ca(2+) buffers and sensors. These molecules are associated with the plasma membrane and different cellular compartments, such as the cytoplasm, nucleus, mitochondria, and cellular reticular network, including the endoplasmic reticulum (ER) to control free and bound Ca(2+) levels in all parts of the cell. Loss of nutrients/energy leads to the loss of cellular homeostasis and disruption of Ca(2+) signaling in both the reticular network and cytoplasmic compartments. As an integral part of cellular physiology and pathology, this leads to activation of ER stress coping responses, such as the unfolded protein response (UPR), and mobilization of pathways to regain ER homeostasis.
Collapse
|
23
|
Ong HL, de Souza LB, Zheng C, Cheng KT, Liu X, Goldsmith CM, Feske S, Ambudkar IS. STIM2 enhances receptor-stimulated Ca²⁺ signaling by promoting recruitment of STIM1 to the endoplasmic reticulum-plasma membrane junctions. Sci Signal 2015; 8:ra3. [PMID: 25587190 DOI: 10.1126/scisignal.2005748] [Citation(s) in RCA: 77] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
A central component of receptor-evoked Ca(2+) signaling is store-operated Ca(2+) entry (SOCE), which is activated by the assembly of STIM1-Orai1 channels in endoplasmic reticulum (ER) and plasma membrane (PM) (ER-PM) junctions in response to depletion of ER Ca(2+). We report that STIM2 enhances agonist-mediated activation of SOCE by promoting STIM1 clustering in ER-PM junctions at low stimulus intensities. Targeted deletion of STIM2 in mouse salivary glands diminished fluid secretion in vivo and SOCE activation in dispersed salivary acinar cells stimulated with low concentrations of muscarinic receptor agonists. STIM2 knockdown in human embryonic kidney (HEK) 293 cells diminished agonist-induced Ca(2+) signaling and nuclear translocation of NFAT (nuclear factor of activated T cells). STIM2 lacking five carboxyl-terminal amino acid residues did not promote formation of STIM1 puncta at low concentrations of agonist, whereas coexpression of STIM2 with STIM1 mutant lacking the polybasic region STIM1ΔK resulted in co-clustering of both proteins. Together, our findings suggest that STIM2 recruits STIM1 to ER-PM junctions at low stimulus intensities when ER Ca(2+) stores are mildly depleted, thus increasing the sensitivity of Ca(2+) signaling to agonists.
Collapse
Affiliation(s)
- Hwei Ling Ong
- Secretory Physiology Section, Molecular Physiology and Therapeutics Branch, National Institute of Dental and Craniofacial Research (NIDCR), National Institutes of Health (NIH), Bethesda, MD 20892, USA
| | - Lorena Brito de Souza
- Secretory Physiology Section, Molecular Physiology and Therapeutics Branch, National Institute of Dental and Craniofacial Research (NIDCR), National Institutes of Health (NIH), Bethesda, MD 20892, USA
| | - Changyu Zheng
- Translational Research Core, Molecular Physiology and Therapeutics Branch, NIDCR, NIH, Bethesda, MD 20892, USA
| | - Kwong Tai Cheng
- Department of Pharmacology, College of Medicine, University of Illinois at Chicago, Chicago, IL 60612, USA
| | - Xibao Liu
- Secretory Physiology Section, Molecular Physiology and Therapeutics Branch, National Institute of Dental and Craniofacial Research (NIDCR), National Institutes of Health (NIH), Bethesda, MD 20892, USA
| | - Corinne M Goldsmith
- Translational Research Core, Molecular Physiology and Therapeutics Branch, NIDCR, NIH, Bethesda, MD 20892, USA
| | - Stefan Feske
- Department of Pathology, New York University Langone Medical Center, New York, NY 10016, USA
| | - Indu S Ambudkar
- Secretory Physiology Section, Molecular Physiology and Therapeutics Branch, National Institute of Dental and Craniofacial Research (NIDCR), National Institutes of Health (NIH), Bethesda, MD 20892, USA.
| |
Collapse
|
24
|
Apodaca G, Brown WJ. Membrane traffic research: challenges for the next decade. Front Cell Dev Biol 2014; 2:52. [PMID: 25364759 PMCID: PMC4207031 DOI: 10.3389/fcell.2014.00052] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2014] [Accepted: 09/02/2014] [Indexed: 01/26/2023] Open
Affiliation(s)
- Gerard Apodaca
- The Renal-Electrolyte Division, Department of Medicine, University of Pittsburgh Pittsburgh, PA, USA
| | - William J Brown
- Molecular Biology and Genetics, Cornell University Ithaca, NY, USA
| |
Collapse
|