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Lemos FO, de Ridder I, Wagner L, Bootman MD, Bultynck G, Yule DI, Parys JB. Tetrameric, active PKM2 inhibits IP 3 receptors, potentially requiring GRP75 as an additional interaction partner. BIOCHIMICA ET BIOPHYSICA ACTA. MOLECULAR CELL RESEARCH 2024; 1871:119796. [PMID: 39038610 DOI: 10.1016/j.bbamcr.2024.119796] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/19/2024] [Revised: 06/05/2024] [Accepted: 07/08/2024] [Indexed: 07/24/2024]
Abstract
Pyruvate kinase M2 (PKM2) is a key glycolytic enzyme interacting with the inositol 1,4,5-trisphosphate receptor (IP3R). This interaction suppresses IP3R-mediated cytosolic [Ca2+] rises. As PKM2 exists in monomeric, dimeric and tetrameric forms displaying different properties including catalytic activity, we investigated the molecular determinants of PKM2 enabling its interaction with IP3Rs. Treatment of HeLa cells with TEPP-46, a compound stabilizing the tetrameric form of PKM2, increased both its catalytic activity and the suppression of IP3R-mediated Ca2+ signals. Consistently, in PKM2 knock-out HeLa cells, PKM2C424L, a tetrameric, highly active PKM2 mutant, but not inactive PKM2K270M or the less active PKM2K305Q, suppressed IP3R-mediated Ca2+ release. Surprisingly, however, in vitro assays did not reveal a direct interaction between purified PKM2 and either the purified Fragment 5 of IP3R1 (a.a. 1932-2216) or the therein located D5SD peptide (a.a. 2078-2098 of IP3R1), the presumed interaction sites of PKM2 on the IP3R. Moreover, on-nucleus patch clamp of heterologously expressed IP3R1 in DT40 cells devoid of endogenous IP3Rs did not reveal any functional effect of purified wild-type PKM2, mutant PKM2 or PKM1 proteins. These results indicate that an additional factor mediates the regulation of the IP3R by PKM2 in cellulo. Immunoprecipitation of GRP75 using HeLa cell lysates co-precipitated IP3R1, IP3R3 and PKM2. Moreover, the D5SD peptide not only disrupted PKM2:IP3R, but also PKM2:GRP75 and GRP75:IP3R interactions. Our data therefore support a model in which catalytically active, tetrameric PKM2 suppresses Ca2+ signaling via the IP3R through a multiprotein complex involving GRP75.
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Affiliation(s)
- Fernanda O Lemos
- Laboratory of Molecular and Cellular Signaling, Department of Cellular and Molecular Medicine & Leuven Kanker Instituut, KU Leuven, Herestraat 49, Campus Gasthuisberg O&N1 - B802, 3000 Leuven, Belgium.
| | - Ian de Ridder
- Laboratory of Molecular and Cellular Signaling, Department of Cellular and Molecular Medicine & Leuven Kanker Instituut, KU Leuven, Herestraat 49, Campus Gasthuisberg O&N1 - B802, 3000 Leuven, Belgium
| | - Larry Wagner
- Department of Pharmacology and Physiology, University of Rochester, Rochester, NY 14642, USA
| | - Martin D Bootman
- School of Life, Health and Chemical Sciences, The Open University, Walton Hall, Milton Keynes MK7 6AA, UK
| | - Geert Bultynck
- Laboratory of Molecular and Cellular Signaling, Department of Cellular and Molecular Medicine & Leuven Kanker Instituut, KU Leuven, Herestraat 49, Campus Gasthuisberg O&N1 - B802, 3000 Leuven, Belgium
| | - David I Yule
- Department of Pharmacology and Physiology, University of Rochester, Rochester, NY 14642, USA
| | - Jan B Parys
- Laboratory of Molecular and Cellular Signaling, Department of Cellular and Molecular Medicine & Leuven Kanker Instituut, KU Leuven, Herestraat 49, Campus Gasthuisberg O&N1 - B802, 3000 Leuven, Belgium.
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2
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Kochkina EN, Kopylova EE, Rogachevskaja OA, Kovalenko NP, Kabanova NV, Kotova PD, Bystrova MF, Kolesnikov SS. Agonist-Induced Ca 2+ Signaling in HEK-293-Derived Cells Expressing a Single IP 3 Receptor Isoform. Cells 2024; 13:562. [PMID: 38607001 PMCID: PMC11011116 DOI: 10.3390/cells13070562] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2023] [Revised: 03/13/2024] [Accepted: 03/18/2024] [Indexed: 04/13/2024] Open
Abstract
In mammals, three genes encode IP3 receptors (IP3Rs), which are involved in agonist-induced Ca2+ signaling in cells of apparently all types. Using the CRISPR/Cas9 approach for disruption of two out of three IP3R genes in HEK-293 cells, we generated three monoclonal cell lines, IP3R1-HEK, IP3R2-HEK, and IP3R3-HEK, with the single functional isoform, IP3R1, IP3R2, and IP3R3, respectively. All engineered cells responded to ACh with Ca2+ transients in an "all-or-nothing" manner, suggesting that each IP3R isotype was capable of mediating CICR. The sensitivity of cells to ACh strongly correlated with the affinity of IP3 binding to an IP3R isoform they expressed. Based on a mathematical model of intracellular Ca2+ signals induced by thapsigargin, a SERCA inhibitor, we developed an approach for estimating relative Ca2+ permeability of Ca2+ store and showed that all three IP3R isoforms contributed to Ca2+ leakage from ER. The relative Ca2+ permeabilities of Ca2+ stores in IP3R1-HEK, IP3R2-HEK, and IP3R3-HEK cells were evaluated as 1:1.75:0.45. Using the genetically encoded sensor R-CEPIA1er for monitoring Ca2+ signals in ER, engineered cells were ranged by resting levels of stored Ca2+ as IP3R3-HEK ≥ IP3R1-HEK > IP3R2-HEK. The developed cell lines could be helpful for further assaying activity, regulation, and pharmacology of individual IP3R isoforms.
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Affiliation(s)
| | | | | | | | | | | | | | - Stanislav S. Kolesnikov
- Institute of Cell Biophysics, Pushchino Scientific Center for Biological Research of the Russian Academy of Sciences, 3 Institutskaya Street, 142290 Pushchino, Russia
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Tao S, Hulpiau P, Wagner LE, Witschas K, Yule DI, Bultynck G, Leybaert L. IP3RPEP6, a novel peptide inhibitor of IP 3 receptor channels that does not affect connexin-43 hemichannels. Acta Physiol (Oxf) 2024; 240:e14086. [PMID: 38240350 DOI: 10.1111/apha.14086] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2023] [Revised: 10/24/2023] [Accepted: 01/01/2024] [Indexed: 02/24/2024]
Abstract
AIM Inositol 1,4,5-trisphosphate receptors (IP3 Rs) are intracellular Ca2+ -release channels with crucial roles in cell function. Current IP3 R inhibitors suffer from off-target effects and poor selectivity towards the three distinct IP3 R subtypes. We developed a novel peptide inhibitor of IP3 Rs and determined its effect on connexin-43 (Cx43) hemichannels, which are co-activated by IP3 R stimulation. METHODS IP3RPEP6 was developed by in silico molecular docking studies and characterized by on-nucleus patch-clamp experiments of IP3 R2 channels and carbachol-induced IP3 -mediated Ca2+ responses in IP3 R1, 2 or 3 expressing cells, triple IP3 R KO cells and astrocytes. Cx43 hemichannels were studied by patch-clamp and ATP-release approaches, and by inhibition with Gap19 peptide. IP3RPEP6 interactions with IP3 Rs were verified by co-immunoprecipitation and affinity pull-down assays. RESULTS IP3RPEP6 concentration-dependently reduced the open probability of IP3 R2 channels and competitively inhibited IP3 Rs in an IC50 order of IP3 R2 (~3.9 μM) < IP3 R3 (~4.3 μM) < IP3 R1 (~9.0 μM), without affecting Cx43 hemichannels or ryanodine receptors. IP3RPEP6 co-immunoprecipitated with IP3 R2 but not with IP3 R1; interaction with IP3 R3 varied between cell types. The IC50 of IP3RPEP6 inhibition of carbachol-induced Ca2+ responses decreased with increasing cellular Cx43 expression. Moreover, Gap19-inhibition of Cx43 hemichannels significantly reduced the amplitude of the IP3 -Ca2+ responses and strongly increased the EC50 of these responses. Finally, we identified palmitoyl-8G-IP3RPEP6 as a membrane-permeable IP3RPEP6 version allowing extracellular application of the IP3 R-inhibiting peptide. CONCLUSION IP3RPEP6 inhibits IP3 R2/R3 at concentrations that have limited effects on IP3 R1. IP3 R activation triggers hemichannel opening, which strongly affects the amplitude and concentration-dependence of IP3 -triggered Ca2+ responses.
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Affiliation(s)
- Siyu Tao
- Department of Basic and Applied Medical Sciences-Physiology Group, Ghent University, Ghent, Belgium
| | - Paco Hulpiau
- Department of Bio-Medical Sciences, HOWEST University of Applied Sciences (Hogeschool West-Vlaanderen), Bruges, Belgium
| | - Larry E Wagner
- Department of Pharmacology and Physiology, School of Medicine and Dentistry, University of Rochester Medical Center, Rochester, New York, USA
| | - Katja Witschas
- Department of Basic and Applied Medical Sciences-Physiology Group, Ghent University, Ghent, Belgium
| | - David I Yule
- Department of Pharmacology and Physiology, School of Medicine and Dentistry, University of Rochester Medical Center, Rochester, New York, USA
| | - Geert Bultynck
- Laboratory of Molecular and Cellular Signaling, Department of Molecular Cell Biology, KU Leuven, Leuven, Belgium
| | - Luc Leybaert
- Department of Basic and Applied Medical Sciences-Physiology Group, Ghent University, Ghent, Belgium
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4
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Friedhoff VN, Lindner B, Falcke M. Modeling IP 3-induced Ca 2+ signaling based on its interspike interval statistics. Biophys J 2023; 122:2818-2831. [PMID: 37312455 PMCID: PMC10398346 DOI: 10.1016/j.bpj.2023.06.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2023] [Revised: 04/24/2023] [Accepted: 06/06/2023] [Indexed: 06/15/2023] Open
Abstract
Inositol 1,4,5-trisphosphate (IP3)-induced Ca2+ signaling is a second messenger system used by almost all eukaryotic cells. Recent research demonstrated randomness of Ca2+ signaling on all structural levels. We compile eight general properties of Ca2+ spiking common to all cell types investigated and suggest a theory of Ca2+ spiking starting from the random behavior of IP3 receptor channel clusters mediating the release of Ca2+ from the endoplasmic reticulum capturing all general properties and pathway-specific behavior. Spike generation begins after the absolute refractory period of the previous spike. According to its hierarchical spreading from initiating channel openings to cell level, we describe it as a first passage process from none to all clusters open while the cell recovers from the inhibition which terminated the previous spike. Our theory reproduces the exponential stimulation response relation of the average interspike interval Tav and its robustness properties, random spike timing with a linear moment relation between Tav and the interspike interval SD and its robustness properties, sensitive dependency of Tav on diffusion properties, and nonoscillatory local dynamics. We explain large cell variability of Tav observed in experiments by variability of channel cluster coupling by Ca2+-induced Ca2+ release, the number of clusters, and IP3 pathway component expression levels. We predict the relation between puff probability and agonist concentration and [IP3] and agonist concentration. Differences of spike behavior between cell types and stimulating agonists are explained by the different types of negative feedback terminating spikes. In summary, the hierarchical random character of spike generation explains all of the identified general properties.
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Affiliation(s)
- Victor Nicolai Friedhoff
- Max Delbrück Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany; Department of Physics, Humboldt University, Berlin, Germany
| | - Benjamin Lindner
- Bernstein Center for Computational Neuroscience Berlin, Berlin, Germany; Department of Physics, Humboldt University, Berlin, Germany
| | - Martin Falcke
- Max Delbrück Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany; Department of Physics, Humboldt University, Berlin, Germany.
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Chung J, Tilūnaitė A, Ladd D, Hunt H, Soeller C, Crampin EJ, Johnston ST, Roderick HL, Rajagopal V. IP 3R activity increases propensity of RyR-mediated sparks by elevating dyadic [Ca 2+]. Math Biosci 2023; 355:108923. [PMID: 36395827 DOI: 10.1016/j.mbs.2022.108923] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2022] [Revised: 10/15/2022] [Accepted: 10/15/2022] [Indexed: 11/16/2022]
Abstract
Calcium (Ca2+) plays a critical role in the excitation contraction coupling (ECC) process that mediates the contraction of cardiomyocytes during each heartbeat. While ryanodine receptors (RyRs) are the primary Ca2+ channels responsible for generating the cell-wide Ca2+ transients during ECC, Ca2+ release, via inositol 1,4,5-trisphosphate (IP3) receptors (IP3Rs) are also reported in cardiomyocytes to elicit ECC-modulating effects. Recent studies suggest that the localization of IP3Rs at dyads grant their ability to modify the occurrence of Ca2+ sparks (elementary Ca2+ release events that constitute cell wide Ca2+ releases associated with ECC) which may underlie their modulatory influence on ECC. Here, we aim to uncover the mechanism by which dyad-localized IP3Rs influence Ca2+ spark dynamics. To this end, we developed a mathematical model of the dyad that incorporates the behaviour of IP3Rs, in addition to RyRs, to reveal the impact of their activity on local Ca2+ handling and consequent Ca2+ spark occurrence and its properties. Consistent with published experimental data, our model predicts that the propensity for Ca2+ spark formation increases in the presence of IP3R activity. Our simulations support the hypothesis that IP3Rs elevate Ca2+ in the dyad, sensitizing proximal RyRs towards activation and hence Ca2+ spark formation. The stochasticity of IP3R gating is an important aspect of this mechanism. However, dyadic IP3R activity lowers the Ca2+ available in the junctional sarcoplasmic reticulum (JSR) for release, thus resulting in Ca2+ sparks with similar durations but lower amplitudes.
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Affiliation(s)
- Joshua Chung
- Department of Biomedical Engineering, The University of Melbourne, Melbourne, VIC 3010, Australia; Laboratory of Experimental Cardiology, Department of Cardiovascular Sciences, KU Leuven, 3000, Leuven, Belgium
| | - Agnė Tilūnaitė
- Department of Biomedical Engineering, The University of Melbourne, Melbourne, VIC 3010, Australia; School of Mathematics and Statistics, The University of Melbourne, Melbourne, VIC 3010, Australia
| | - David Ladd
- Department of Biomedical Engineering, The University of Melbourne, Melbourne, VIC 3010, Australia; School of Mathematics and Statistics, The University of Melbourne, Melbourne, VIC 3010, Australia; ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, School of Chemical and Biomedical Engineering, The University of Melbourne, Melbourne, VIC 3010, Australia
| | - Hilary Hunt
- School of Mathematics and Statistics, The University of Melbourne, Melbourne, VIC 3010, Australia
| | | | - Edmund J Crampin
- Department of Biomedical Engineering, The University of Melbourne, Melbourne, VIC 3010, Australia; School of Mathematics and Statistics, The University of Melbourne, Melbourne, VIC 3010, Australia; ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, School of Chemical and Biomedical Engineering, The University of Melbourne, Melbourne, VIC 3010, Australia
| | - Stuart T Johnston
- School of Mathematics and Statistics, The University of Melbourne, Melbourne, VIC 3010, Australia; ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, School of Chemical and Biomedical Engineering, The University of Melbourne, Melbourne, VIC 3010, Australia
| | - H Llewelyn Roderick
- Laboratory of Experimental Cardiology, Department of Cardiovascular Sciences, KU Leuven, 3000, Leuven, Belgium.
| | - Vijay Rajagopal
- Department of Biomedical Engineering, The University of Melbourne, Melbourne, VIC 3010, Australia; Baker Department of Cardiometabolic Health, The University of Melbourne, Melbourne, VIC 3010, Australia.
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6
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Atakpa-Adaji P, Ivanova A. IP 3R at ER-Mitochondrial Contact Sites: Beyond the IP 3R-GRP75-VDAC1 Ca 2+ Funnel. CONTACT (THOUSAND OAKS (VENTURA COUNTY, CALIF.)) 2023; 6:25152564231181020. [PMID: 37426575 PMCID: PMC10328019 DOI: 10.1177/25152564231181020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/28/2023] [Accepted: 05/23/2023] [Indexed: 07/11/2023]
Abstract
Membrane contact sites (MCS) circumvent the topological constraints of functional coupling between different membrane-bound organelles by providing a means of communication and exchange of materials. One of the most characterised contact sites in the cell is that between the endoplasmic reticulum and the mitochondrial (ERMCS) whose function is to couple cellular Ca2+ homeostasis and mitochondrial function. Inositol 1,4,5-trisphosphate receptors (IP3Rs) on the ER, glucose-regulated protein 75 (GRP 75) and voltage-dependent anion channel 1 (VDAC1) on the outer mitochondrial membrane are the canonical component of the Ca2+ transfer unit at ERMCS. These are often reported to form a Ca2+ funnel that fuels the mitochondrial low-affinity Ca2+ uptake system. We assess the available evidence on the IP3R subtype selectivity at the ERMCS and consider if IP3Rs have other roles at the ERMCS beyond providing Ca2+. Growing evidence suggests that all three IP3R subtypes can localise and regulate Ca2+ signalling at ERMCS. Furthermore, IP3Rs may be structurally important for assembly of the ERMCS in addition to their role in providing Ca2+ at these sites. Evidence that various binding partners regulate the assembly and Ca2+ transfer at ERMCS populated by IP3R-GRP75-VDAC1, suggesting that cells have evolved mechanisms that stabilise these junctions forming a Ca2+ microdomain that is required to fuel mitochondrial Ca2+ uptake.
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Affiliation(s)
- Peace Atakpa-Adaji
- Department of Pharmacology, University of Cambridge, Tennis Court Road, Cambridge, CB2 1PD, UK
| | - Adelina Ivanova
- Department of Pharmacology, University of Cambridge, Tennis Court Road, Cambridge, CB2 1PD, UK
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7
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Fan G, Baker MR, Terry LE, Arige V, Chen M, Seryshev AB, Baker ML, Ludtke SJ, Yule DI, Serysheva II. Conformational motions and ligand-binding underlying gating and regulation in IP 3R channel. Nat Commun 2022; 13:6942. [PMID: 36376291 PMCID: PMC9663519 DOI: 10.1038/s41467-022-34574-1] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2022] [Accepted: 10/28/2022] [Indexed: 11/16/2022] Open
Abstract
Inositol-1,4,5-trisphosphate receptors (IP3Rs) are activated by IP3 and Ca2+ and their gating is regulated by various intracellular messengers that finely tune the channel activity. Here, using single particle cryo-EM analysis we determined 3D structures of the nanodisc-reconstituted IP3R1 channel in two ligand-bound states. These structures provide unprecedented details governing binding of IP3, Ca2+ and ATP, revealing conformational changes that couple ligand-binding to channel opening. Using a deep-learning approach and 3D variability analysis we extracted molecular motions of the key protein domains from cryo-EM density data. We find that IP3 binding relies upon intrinsic flexibility of the ARM2 domain in the tetrameric channel. Our results highlight a key role of dynamic side chains in regulating gating behavior of IP3R channels. This work represents a stepping-stone to developing mechanistic understanding of conformational pathways underlying ligand-binding, activation and regulation of the channel.
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Affiliation(s)
- Guizhen Fan
- Department of Biochemistry and Molecular Biology, Structural Biology Imaging Center, McGovern Medical School at The University of Texas Health Science Center at Houston, 6431, Fannin Street, Houston, TX, USA
| | - Mariah R Baker
- Department of Biochemistry and Molecular Biology, Structural Biology Imaging Center, McGovern Medical School at The University of Texas Health Science Center at Houston, 6431, Fannin Street, Houston, TX, USA
| | - Lara E Terry
- Department of Pharmacology and Physiology, School of Medicine and Dentistry, University of Rochester, Rochester, NY, USA
| | - Vikas Arige
- Department of Pharmacology and Physiology, School of Medicine and Dentistry, University of Rochester, Rochester, NY, USA
| | - Muyuan Chen
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, One Baylor Plaza, Houston, TX, USA
- SLAC National Accelerator Laboratory, Menlo Park, CA, USA
| | - Alexander B Seryshev
- Department of Biochemistry and Molecular Biology, Structural Biology Imaging Center, McGovern Medical School at The University of Texas Health Science Center at Houston, 6431, Fannin Street, Houston, TX, USA
| | - Matthew L Baker
- Department of Biochemistry and Molecular Biology, Structural Biology Imaging Center, McGovern Medical School at The University of Texas Health Science Center at Houston, 6431, Fannin Street, Houston, TX, USA
| | - Steven J Ludtke
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, One Baylor Plaza, Houston, TX, USA
| | - David I Yule
- Department of Pharmacology and Physiology, School of Medicine and Dentistry, University of Rochester, Rochester, NY, USA.
| | - Irina I Serysheva
- Department of Biochemistry and Molecular Biology, Structural Biology Imaging Center, McGovern Medical School at The University of Texas Health Science Center at Houston, 6431, Fannin Street, Houston, TX, USA.
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8
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Arige V, Terry LE, Wagner LE, Malik S, Baker MR, Fan G, Joseph SK, Serysheva II, Yule DI. Functional determination of calcium-binding sites required for the activation of inositol 1,4,5-trisphosphate receptors. Proc Natl Acad Sci U S A 2022; 119:e2209267119. [PMID: 36122240 PMCID: PMC9522344 DOI: 10.1073/pnas.2209267119] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2022] [Accepted: 08/23/2022] [Indexed: 01/25/2023] Open
Abstract
Inositol 1,4,5-trisphosphate receptors (IP3Rs) initiate a diverse array of physiological responses by carefully orchestrating intracellular calcium (Ca2+) signals in response to various external cues. Notably, IP3R channel activity is determined by several obligatory factors, including IP3, Ca2+, and ATP. The critical basic amino acid residues in the N-terminal IP3-binding core (IBC) region that facilitate IP3 binding are well characterized. In contrast, the residues conferring regulation by Ca2+ have yet to be ascertained. Using comparative structural analysis of Ca2+-binding sites identified in two main families of intracellular Ca2+-release channels, ryanodine receptors (RyRs) and IP3Rs, we identified putative acidic residues coordinating Ca2+ in the cytosolic calcium sensor region in IP3Rs. We determined the consequences of substituting putative Ca2+ binding, acidic residues in IP3R family members. We show that the agonist-induced Ca2+ release, single-channel open probability (P0), and Ca2+ sensitivities are markedly altered when the negative charge on the conserved acidic side chain residues is neutralized. Remarkably, neutralizing the negatively charged side chain on two of the residues individually in the putative Ca2+-binding pocket shifted the Ca2+ required to activate IP3R to higher concentrations, indicating that these residues likely are a component of the Ca2+ activation site in IP3R. Taken together, our findings indicate that Ca2+ binding to a well-conserved activation site is a common underlying mechanism resulting in increased channel activity shared by IP3Rs and RyRs.
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Affiliation(s)
- Vikas Arige
- Department of Pharmacology and Physiology, University of Rochester, Rochester, NY 14642
| | - Lara E. Terry
- Department of Pharmacology and Physiology, University of Rochester, Rochester, NY 14642
| | - Larry E. Wagner
- Department of Pharmacology and Physiology, University of Rochester, Rochester, NY 14642
| | - Sundeep Malik
- Department of Pharmacology and Physiology, University of Rochester, Rochester, NY 14642
| | - Mariah R. Baker
- Department of Biochemistry and Molecular Biology, Structural Biology Imaging Center, McGovern Medical School, The University of Texas Health Science Center at Houston, Houston, TX 77030
| | - Guizhen Fan
- Department of Biochemistry and Molecular Biology, Structural Biology Imaging Center, McGovern Medical School, The University of Texas Health Science Center at Houston, Houston, TX 77030
| | - Suresh K. Joseph
- Department of Pathology, Anatomy, and Cell Biology, Thomas Jefferson University, Philadelphia, PA 19107
| | - Irina I. Serysheva
- Department of Biochemistry and Molecular Biology, Structural Biology Imaging Center, McGovern Medical School, The University of Texas Health Science Center at Houston, Houston, TX 77030
| | - David I. Yule
- Department of Pharmacology and Physiology, University of Rochester, Rochester, NY 14642
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9
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Rosa N, Speelman-Rooms F, Parys JB, Bultynck G. Modulation of Ca 2+ signaling by antiapoptotic Bcl-2 versus Bcl-xL: From molecular mechanisms to relevance for cancer cell survival. Biochim Biophys Acta Rev Cancer 2022; 1877:188791. [PMID: 36162541 DOI: 10.1016/j.bbcan.2022.188791] [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: 06/08/2022] [Revised: 08/29/2022] [Accepted: 08/29/2022] [Indexed: 11/17/2022]
Abstract
Members of the Bcl-2-protein family are key controllers of apoptotic cell death. The family is divided into antiapoptotic (including Bcl-2 itself, Bcl-xL, Mcl-1, etc.) and proapoptotic members (Bax, Bak, Bim, Bim, Puma, Noxa, Bad, etc.). These proteins are well known for their canonical role in the mitochondria, where they control mitochondrial outer membrane permeabilization and subsequent apoptosis. However, several proteins are recognized as modulators of intracellular Ca2+ signals that originate from the endoplasmic reticulum (ER), the major intracellular Ca2+-storage organelle. More than 25 years ago, Bcl-2, the founding member of the family, was reported to control apoptosis through Ca2+ signaling. Further work elucidated that Bcl-2 directly targets and inhibits inositol 1,4,5-trisphosphate receptors (IP3Rs), thereby suppressing proapoptotic Ca2+ signaling. In addition to Bcl-2, Bcl-xL was also shown to impact cell survival by sensitizing IP3R function, thereby promoting prosurvival oscillatory Ca2+ release. However, new work challenges this model and demonstrates that Bcl-2 and Bcl-xL can both function as inhibitors of IP3Rs. This suggests that, depending on the cell context, Bcl-xL could support very distinct Ca2+ patterns. This not only raises several questions but also opens new possibilities for the treatment of Bcl-xL-dependent cancers. In this review, we will discuss the similarities and divergences between Bcl-2 and Bcl-xL regarding Ca2+ homeostasis and IP3R modulation from both a molecular and a functional point of view, with particular emphasis on cancer cell death resistance mechanisms.
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Affiliation(s)
- Nicolas Rosa
- KU Leuven, Laboratory of Molecular & Cellular Signaling, Department of Cellular & Molecular Medicine, Campus Gasthuisberg O/N-I bus 802, Herestraat 49, BE-3000 Leuven, Belgium
| | - Femke Speelman-Rooms
- KU Leuven, Laboratory of Molecular & Cellular Signaling, Department of Cellular & Molecular Medicine, Campus Gasthuisberg O/N-I bus 802, Herestraat 49, BE-3000 Leuven, Belgium
| | - Jan B Parys
- KU Leuven, Laboratory of Molecular & Cellular Signaling, Department of Cellular & Molecular Medicine, Campus Gasthuisberg O/N-I bus 802, Herestraat 49, BE-3000 Leuven, Belgium
| | - Geert Bultynck
- KU Leuven, Laboratory of Molecular & Cellular Signaling, Department of Cellular & Molecular Medicine, Campus Gasthuisberg O/N-I bus 802, Herestraat 49, BE-3000 Leuven, Belgium.
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10
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Rosa N, Ivanova H, Wagner LE, Kale J, La Rovere R, Welkenhuyzen K, Louros N, Karamanou S, Shabardina V, Lemmens I, Vandermarliere E, Hamada K, Ando H, Rousseau F, Schymkowitz J, Tavernier J, Mikoshiba K, Economou A, Andrews DW, Parys JB, Yule DI, Bultynck G. Bcl-xL acts as an inhibitor of IP 3R channels, thereby antagonizing Ca 2+-driven apoptosis. Cell Death Differ 2021; 29:788-805. [PMID: 34750538 PMCID: PMC8990011 DOI: 10.1038/s41418-021-00894-w] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2021] [Revised: 10/06/2021] [Accepted: 10/07/2021] [Indexed: 11/09/2022] Open
Abstract
Anti-apoptotic Bcl-2-family members not only act at mitochondria but also at the endoplasmic reticulum, where they impact Ca2+ dynamics by controlling IP3 receptor (IP3R) function. Current models propose distinct roles for Bcl-2 vs. Bcl-xL, with Bcl-2 inhibiting IP3Rs and preventing pro-apoptotic Ca2+ release and Bcl-xL sensitizing IP3Rs to low [IP3] and promoting pro-survival Ca2+ oscillations. We here demonstrate that Bcl-xL too inhibits IP3R-mediated Ca2+ release by interacting with the same IP3R regions as Bcl-2. Via in silico superposition, we previously found that the residue K87 of Bcl-xL spatially resembled K17 of Bcl-2, a residue critical for Bcl-2's IP3R-inhibitory properties. Mutagenesis of K87 in Bcl-xL impaired its binding to IP3R and abrogated Bcl-xL's inhibitory effect on IP3Rs. Single-channel recordings demonstrate that purified Bcl-xL, but not Bcl-xLK87D, suppressed IP3R single-channel openings stimulated by sub-maximal and threshold [IP3]. Moreover, we demonstrate that Bcl-xL-mediated inhibition of IP3Rs contributes to its anti-apoptotic properties against Ca2+-driven apoptosis. Staurosporine (STS) elicits long-lasting Ca2+ elevations in wild-type but not in IP3R-knockout HeLa cells, sensitizing the former to STS treatment. Overexpression of Bcl-xL in wild-type HeLa cells suppressed STS-induced Ca2+ signals and cell death, while Bcl-xLK87D was much less effective in doing so. In the absence of IP3Rs, Bcl-xL and Bcl-xLK87D were equally effective in suppressing STS-induced cell death. Finally, we demonstrate that endogenous Bcl-xL also suppress IP3R activity in MDA-MB-231 breast cancer cells, whereby Bcl-xL knockdown augmented IP3R-mediated Ca2+ release and increased the sensitivity towards STS, without altering the ER Ca2+ content. Hence, this study challenges the current paradigm of divergent functions for Bcl-2 and Bcl-xL in Ca2+-signaling modulation and reveals that, similarly to Bcl-2, Bcl-xL inhibits IP3R-mediated Ca2+ release and IP3R-driven cell death. Our work further underpins that IP3R inhibition is an integral part of Bcl-xL's anti-apoptotic function.
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Affiliation(s)
- Nicolas Rosa
- KU Leuven, Laboratory of Molecular and Cellular Signaling, Department of Cellular and Molecular Medicine, and Leuven Kanker Instituut, Campus Gasthuisberg O/N-1 Box 802, Herestraat 49, 3000, Leuven, Belgium
| | - Hristina Ivanova
- KU Leuven, Laboratory of Molecular and Cellular Signaling, Department of Cellular and Molecular Medicine, and Leuven Kanker Instituut, Campus Gasthuisberg O/N-1 Box 802, Herestraat 49, 3000, Leuven, Belgium
| | - Larry E Wagner
- Department of Pharmacology and Physiology, School of Medicine and Dentistry, University of Rochester, 601 Elmwood Avenue, Box 711, Rochester, NY, 14642, USA
| | - Justin Kale
- Biological Sciences, Sunnybrook Research Institute, University of Toronto, Toronto, ON, M4N 3M5, Canada
| | - Rita La Rovere
- KU Leuven, Laboratory of Molecular and Cellular Signaling, Department of Cellular and Molecular Medicine, and Leuven Kanker Instituut, Campus Gasthuisberg O/N-1 Box 802, Herestraat 49, 3000, Leuven, Belgium
| | - Kirsten Welkenhuyzen
- KU Leuven, Laboratory of Molecular and Cellular Signaling, Department of Cellular and Molecular Medicine, and Leuven Kanker Instituut, Campus Gasthuisberg O/N-1 Box 802, Herestraat 49, 3000, Leuven, Belgium
| | - Nikolaos Louros
- VIB Center for Brain and Disease Research, Campus Gasthuisberg O/N-1bis Box 802, Herestraat 49, 3000, Leuven, Belgium.,KU Leuven, Switch Laboratory, Department of Cellular and Molecular Medicine, Campus Gasthuisberg O/N-1bis Box 802, Herestraat 49, 3000, Leuven, Belgium
| | - Spyridoula Karamanou
- KU Leuven, Laboratory of Molecular Bacteriology, Department of Microbiology and Immunology, Rega Institute for Medical Research, Campus Gasthuisberg P.O, Box 1037, Herestraat 49, 3000, Leuven, Belgium
| | - Victoria Shabardina
- Institut of Evolutionary Biology, CSIC-Universitat Pompeu Fabra, Passeig Marítim de la Barceloneta 37-49, 08003, Barcelona, Spain
| | - Irma Lemmens
- Cytokine Receptor Laboratory, Faculty of Medicine and Health Sciences, Department of Biomolecular Medicine, Ghent University, and Center for Medical Biotechnology, VIB, Albert Baertsoenkaai 3, B-9000, Ghent, Belgium
| | | | - Kozo Hamada
- Shanghai Institute for Advanced Immunochemical Studies, ShanghaiTech University, 201210, Shanghai, China
| | - Hideaki Ando
- Laboratory for Developmental Neurobiology, RIKEN Brain Science Institute, 2-1 Hirosawa, Wako, 351-0198, Saitama, Japan
| | - Frederic Rousseau
- VIB Center for Brain and Disease Research, Campus Gasthuisberg O/N-1bis Box 802, Herestraat 49, 3000, Leuven, Belgium.,KU Leuven, Switch Laboratory, Department of Cellular and Molecular Medicine, Campus Gasthuisberg O/N-1bis Box 802, Herestraat 49, 3000, Leuven, Belgium
| | - Joost Schymkowitz
- VIB Center for Brain and Disease Research, Campus Gasthuisberg O/N-1bis Box 802, Herestraat 49, 3000, Leuven, Belgium.,KU Leuven, Switch Laboratory, Department of Cellular and Molecular Medicine, Campus Gasthuisberg O/N-1bis Box 802, Herestraat 49, 3000, Leuven, Belgium
| | - Jan Tavernier
- Cytokine Receptor Laboratory, Faculty of Medicine and Health Sciences, Department of Biomolecular Medicine, Ghent University, and Center for Medical Biotechnology, VIB, Albert Baertsoenkaai 3, B-9000, Ghent, Belgium
| | - Katsuhiko Mikoshiba
- Shanghai Institute for Advanced Immunochemical Studies, ShanghaiTech University, 201210, Shanghai, China.,Faculty of Science, Toho University, Miyama 2-2-1, Funabashi, 274-8510, Chiba, Japan
| | - Anastassios Economou
- KU Leuven, Laboratory of Molecular Bacteriology, Department of Microbiology and Immunology, Rega Institute for Medical Research, Campus Gasthuisberg P.O, Box 1037, Herestraat 49, 3000, Leuven, Belgium
| | - David W Andrews
- Biological Sciences, Sunnybrook Research Institute, University of Toronto, Toronto, ON, M4N 3M5, Canada
| | - Jan B Parys
- KU Leuven, Laboratory of Molecular and Cellular Signaling, Department of Cellular and Molecular Medicine, and Leuven Kanker Instituut, Campus Gasthuisberg O/N-1 Box 802, Herestraat 49, 3000, Leuven, Belgium
| | - David I Yule
- Department of Pharmacology and Physiology, School of Medicine and Dentistry, University of Rochester, 601 Elmwood Avenue, Box 711, Rochester, NY, 14642, USA
| | - Geert Bultynck
- KU Leuven, Laboratory of Molecular and Cellular Signaling, Department of Cellular and Molecular Medicine, and Leuven Kanker Instituut, Campus Gasthuisberg O/N-1 Box 802, Herestraat 49, 3000, Leuven, Belgium.
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11
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Costiniti V, Bomfim GH, Mitaishvili E, Son GY, Li Y, Lacruz RS. Calcium Transport in Specialized Dental Epithelia and Its Modulation by Fluoride. Front Endocrinol (Lausanne) 2021; 12:730913. [PMID: 34456880 PMCID: PMC8385142 DOI: 10.3389/fendo.2021.730913] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/25/2021] [Accepted: 07/26/2021] [Indexed: 11/25/2022] Open
Abstract
Most cells use calcium (Ca2+) as a second messenger to convey signals that affect a multitude of biological processes. The ability of Ca2+ to bind to proteins to alter their charge and conformation is essential to achieve its signaling role. Cytosolic Ca2+ (cCa2+) concentration is maintained low at ~100 nM so that the impact of elevations in cCa2+ is readily sensed and transduced by cells. However, such elevations in cCa2+ must be transient to prevent detrimental effects. Cells have developed a variety of systems to rapidly clear the excess of cCa2+ including Ca2+ pumps, exchangers and sequestering Ca2+ within intracellular organelles. This Ca2+ signaling toolkit is evolutionarily adapted so that each cell, tissue, and organ can fulfill its biological function optimally. One of the most specialized cells in mammals are the enamel forming cells, the ameloblasts, which also handle large quantities of Ca2+. The end goal of ameloblasts is to synthesize, secrete and mineralize a unique proteinaceous matrix without the benefit of remodeling or repair mechanisms. Ca2+ uptake into ameloblasts is mainly regulated by the store operated Ca2+ entry (SOCE) before it is transported across the polarized ameloblasts to reach the insulated enamel space. Here we review the ameloblasts Ca2+ signaling toolkit and address how the common electronegative non-metal fluoride can alter its function, potentially addressing the biology of dental fluorosis.
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Affiliation(s)
| | | | | | | | | | - Rodrigo S. Lacruz
- Department Molecular Pathobiology, College of Dentistry, New York University, New York, NY, United States
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12
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Zhang Q, Li W, Ayidaerhan N, Han W, Chen Y, Song W, Yue Y. IP 3 R attenuates oxidative stress and inflammation damage in smoking-induced COPD by promoting autophagy. J Cell Mol Med 2021; 25:6174-6187. [PMID: 34060199 PMCID: PMC8256356 DOI: 10.1111/jcmm.16546] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2020] [Revised: 02/14/2021] [Accepted: 03/22/2021] [Indexed: 02/06/2023] Open
Abstract
Tobacco smoking is one of the most important risk factors for chronic obstructive pulmonary disease (COPD). However, the most critical genes and proteins remain poorly understood. Therefore, we aimed to investigate these hub genes and proteins in tobacco smoke-induced COPD, together with the potential mechanism(s). Differentially expressed genes (DEGs) were analysed between smokers and patients with COPD. mRNA expression and protein expression of IP3 R were confirmed in patients with COPD and extracted smoke solution (ESS)-treated human bronchial epithelial (HBE) cells. Moreover, expression of oxidative stress, inflammatory cytokines and/or autophagy-related protein was tested when IP3 R was silenced or overexpressed in ESS-treated and/or 3-MA-treated cells. A total of 30 DEGs were obtained between patients with COPD and smoker samples. IP3 R was identified as one of the key targets in tobacco smoke-induced COPD. In addition, IP3 R was significantly decreased in patients with COPD and ESS-treated cells. Loss of IP3 R statistically increased expression of oxidative stress and inflammatory cytokines in ESS-treated HBE cells, and overexpression of IP3 R reversed the above functions. Furthermore, the autophagy-related proteins (Atg5, LC3 and Beclin1) were statistically decreased, and p62 was increased by silencing of IP3 R cells, while overexpression of IP3 R showed contrary results. Additionally, we detected that administration of 3-MA significantly reversed the protective effects of IP3 R overexpression on ESS-induced oxidative stress and inflammatory injury. Our results suggest that IP3 R might exert a protective role against ESS-induced oxidative stress and inflammation damage in HBE cells. These protective effects might be associated with promoting autophagy.
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Affiliation(s)
- Qiang Zhang
- Department of Pulmonary and Critical Care MedicineShengjing Hospital of China Medical UniversityShenyangChina
| | - Wei Li
- Key Laboratory of Intelligent Computing in Medical ImageMinistry of EducationNortheastern UniversityShenyangChina
| | - Nahemuguli Ayidaerhan
- Department of Pulmonary and Critical Care MedicineTarbagatay Prefecture People’s HospitalTachengChina
| | - Wuxin Han
- Department of Clinical LaboratoryTarbagatay Prefecture People’s HospitalTachengChina
| | - Yingying Chen
- Department of Pulmonary and Critical Care MedicineShengjing Hospital of China Medical UniversityShenyangChina
| | - Wei Song
- Department of Pulmonary and Critical Care MedicineShengjing Hospital of China Medical UniversityShenyangChina
| | - Yuanyi Yue
- Department of Gastroenterology MedicineShengjing Hospital of China Medical UniversityShenyangChina
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13
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Ahumada-Castro U, Bustos G, Silva-Pavez E, Puebla-Huerta A, Lovy A, Cárdenas C. In the Right Place at the Right Time: Regulation of Cell Metabolism by IP3R-Mediated Inter-Organelle Ca 2+ Fluxes. Front Cell Dev Biol 2021; 9:629522. [PMID: 33738285 PMCID: PMC7960657 DOI: 10.3389/fcell.2021.629522] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2020] [Accepted: 01/19/2021] [Indexed: 12/18/2022] Open
Abstract
In the last few years, metabolism has been shown to be controlled by cross-organelle communication. The relationship between the endoplasmic reticulum and mitochondria/lysosomes is the most studied; here, inositol 1,4,5-triphosphate (IP3) receptor (IP3R)-mediated calcium (Ca2+) release plays a central role. Recent evidence suggests that IP3R isoforms participate in synthesis and degradation pathways. This minireview will summarize the current findings in this area, emphasizing the critical role of Ca2+ communication on organelle function as well as catabolism and anabolism, particularly in cancer.
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Affiliation(s)
- Ulises Ahumada-Castro
- Geroscience Center for Brain Health and Metabolism, Center for Integrative Biology, Faculty of Sciences, Universidad Mayor, Santiago, Chile
| | - Galdo Bustos
- Geroscience Center for Brain Health and Metabolism, Center for Integrative Biology, Faculty of Sciences, Universidad Mayor, Santiago, Chile
| | - Eduardo Silva-Pavez
- Geroscience Center for Brain Health and Metabolism, Center for Integrative Biology, Faculty of Sciences, Universidad Mayor, Santiago, Chile
| | - Andrea Puebla-Huerta
- Geroscience Center for Brain Health and Metabolism, Center for Integrative Biology, Faculty of Sciences, Universidad Mayor, Santiago, Chile
| | - Alenka Lovy
- Geroscience Center for Brain Health and Metabolism, Center for Integrative Biology, Faculty of Sciences, Universidad Mayor, Santiago, Chile.,Department of Neuroscience, Center for Neuroscience Research, Tufts University School of Medicine, Boston, MA, United States
| | - César Cárdenas
- Geroscience Center for Brain Health and Metabolism, Center for Integrative Biology, Faculty of Sciences, Universidad Mayor, Santiago, Chile.,Buck Institute for Research on Aging, Novato, CA, United States.,Department of Chemistry and Biochemistry, University of California, Santa Barbara, Santa Barbara, CA, United States
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14
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Gambardella J, Morelli MB, Wang X, Castellanos V, Mone P, Santulli G. The discovery and development of IP3 receptor modulators: an update. Expert Opin Drug Discov 2021; 16:709-718. [PMID: 33356639 DOI: 10.1080/17460441.2021.1858792] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Introduction: Inositol 1,4,5-trisphosphate receptors (IP3Rs) are intracellular calcium (Ca2+) release channels located on the endoplasmic/sarcoplasmic reticulum. The availability of the structure of the ligand-binding domain of IP3Rs has enabled the design of compatible ligands, but the limiting step remains their actual effectiveness in a biological context.Areas covered: This article summarizes the compelling literature on both agonists and antagonists targeting IP3Rs, emphasizing their strengths and limitations. The main challenges toward the discovery and development of IP3 receptor modulators are also described.Expert opinion: Despite significant progress in recent years, the pharmacology of IP3R still has major drawbacks, especially concerning the availability of specific antag onists. Moreover, drugs specifically targeting the three different subtypes of IP3R are especially needed.
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Affiliation(s)
- Jessica Gambardella
- Department of Medicine (Division of Cardiology), Wilf Family Cardiovascular Research Institute, Einstein Institute for Aging Research, Albert Einstein College of Medicine, Montefiore University Hospital, New York City, USA.,Department of Molecular Pharmacology, Fleischer Institute for Diabetes and Metabolism, Einstein-Sinai Diabetes Research Center (ES-DRC), Albert Einstein College of Medicine, New York City, USA.,Department of Advanced Biomedical Sciences, "Federico II" University, Naples, Italy.,International Translational Research and Medical Education (ITME), Naples, Italy
| | - Marco B Morelli
- Department of Medicine (Division of Cardiology), Wilf Family Cardiovascular Research Institute, Einstein Institute for Aging Research, Albert Einstein College of Medicine, Montefiore University Hospital, New York City, USA.,Department of Molecular Pharmacology, Fleischer Institute for Diabetes and Metabolism, Einstein-Sinai Diabetes Research Center (ES-DRC), Albert Einstein College of Medicine, New York City, USA
| | - Xujun Wang
- Department of Medicine (Division of Cardiology), Wilf Family Cardiovascular Research Institute, Einstein Institute for Aging Research, Albert Einstein College of Medicine, Montefiore University Hospital, New York City, USA
| | - Vanessa Castellanos
- Department of Medicine (Division of Cardiology), Wilf Family Cardiovascular Research Institute, Einstein Institute for Aging Research, Albert Einstein College of Medicine, Montefiore University Hospital, New York City, USA
| | - Pasquale Mone
- University of Campania "Luigi Vanvitelli", Naples, Italy
| | - Gaetano Santulli
- Department of Medicine (Division of Cardiology), Wilf Family Cardiovascular Research Institute, Einstein Institute for Aging Research, Albert Einstein College of Medicine, Montefiore University Hospital, New York City, USA.,Department of Molecular Pharmacology, Fleischer Institute for Diabetes and Metabolism, Einstein-Sinai Diabetes Research Center (ES-DRC), Albert Einstein College of Medicine, New York City, USA.,Department of Advanced Biomedical Sciences, "Federico II" University, Naples, Italy.,International Translational Research and Medical Education (ITME), Naples, Italy
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15
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The role of Ca2+ signalling in the physiology and pathophysiology of exocrine pancreas. CURRENT OPINION IN PHYSIOLOGY 2020. [DOI: 10.1016/j.cophys.2020.07.013] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
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16
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Rosa N, Sneyers F, Parys JB, Bultynck G. Type 3 IP 3 receptors: The chameleon in cancer. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2020; 351:101-148. [PMID: 32247578 DOI: 10.1016/bs.ircmb.2020.02.003] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Inositol 1,4,5-trisphosphate (IP3) receptors (IP3Rs), intracellular calcium (Ca2+) release channels, fulfill key functions in cell death and survival processes, whose dysregulation contributes to oncogenesis. This is essentially due to the presence of IP3Rs in microdomains of the endoplasmic reticulum (ER) in close proximity to the mitochondria. As such, IP3Rs enable efficient Ca2+ transfers from the ER to the mitochondria, thus regulating metabolism and cell fate. This review focuses on one of the three IP3R isoforms, the type 3 IP3R (IP3R3), which is linked to proapoptotic ER-mitochondrial Ca2+ transfers. Alterations in IP3R3 expression have been highlighted in numerous cancer types, leading to dysregulations of Ca2+ signaling and cellular functions. However, the outcome of IP3R3-mediated Ca2+ transfers for mitochondrial function is complex with opposing effects on oncogenesis. IP3R3 can either suppress cancer by promoting cell death and cellular senescence or support cancer by driving metabolism, anabolic processes, cell cycle progression, proliferation and invasion. The aim of this review is to provide an overview of IP3R3 dysregulations in cancer and describe how such dysregulations alter critical cellular processes such as proliferation or cell death and survival. Here, we pose that the IP3R3 isoform is not only linked to proapoptotic ER-mitochondrial Ca2+ transfers but might also be involved in prosurvival signaling.
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Affiliation(s)
- Nicolas Rosa
- KU Leuven, Laboratory of Molecular and Cellular Signaling, Department of Cellular and Molecular Medicine and Leuven Kanker Instituut (LKI), Leuven, Belgium
| | - Flore Sneyers
- KU Leuven, Laboratory of Molecular and Cellular Signaling, Department of Cellular and Molecular Medicine and Leuven Kanker Instituut (LKI), Leuven, Belgium
| | - Jan B Parys
- KU Leuven, Laboratory of Molecular and Cellular Signaling, Department of Cellular and Molecular Medicine and Leuven Kanker Instituut (LKI), Leuven, Belgium
| | - Geert Bultynck
- KU Leuven, Laboratory of Molecular and Cellular Signaling, Department of Cellular and Molecular Medicine and Leuven Kanker Instituut (LKI), Leuven, Belgium.
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17
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Affiliation(s)
- Xiang-Na Guo
- Department of Anesthesiology, Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - Xin Ma
- Department of Anesthesiology, Nanfang Hospital, Southern Medical University, Guangzhou, China
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18
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Ivanova H, Wagner LE, Tanimura A, Vandermarliere E, Luyten T, Welkenhuyzen K, Alzayady KJ, Wang L, Hamada K, Mikoshiba K, De Smedt H, Martens L, Yule DI, Parys JB, Bultynck G. Bcl-2 and IP 3 compete for the ligand-binding domain of IP 3Rs modulating Ca 2+ signaling output. Cell Mol Life Sci 2019; 76:3843-3859. [PMID: 30989245 PMCID: PMC11105292 DOI: 10.1007/s00018-019-03091-8] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2018] [Revised: 03/21/2019] [Accepted: 04/01/2019] [Indexed: 12/27/2022]
Abstract
Bcl-2 proteins have emerged as critical regulators of intracellular Ca2+ dynamics by directly targeting and inhibiting the IP3 receptor (IP3R), a major intracellular Ca2+-release channel. Here, we demonstrate that such inhibition occurs under conditions of basal, but not high IP3R activity, since overexpressed and purified Bcl-2 (or its BH4 domain) can inhibit IP3R function provoked by low concentration of agonist or IP3, while fails to attenuate against high concentration of agonist or IP3. Surprisingly, Bcl-2 remained capable of inhibiting IP3R1 channels lacking the residues encompassing the previously identified Bcl-2-binding site (a.a. 1380-1408) located in the ARM2 domain, part of the modulatory region. Using a plethora of computational, biochemical and biophysical methods, we demonstrate that Bcl-2 and more particularly its BH4 domain bind to the ligand-binding domain (LBD) of IP3R1. In line with this finding, the interaction between the LBD and Bcl-2 (or its BH4 domain) was sensitive to IP3 and adenophostin A, ligands of the IP3R. Vice versa, the BH4 domain of Bcl-2 counteracted the binding of IP3 to the LBD. Collectively, our work reveals a novel mechanism by which Bcl-2 influences IP3R activity at the level of the LBD. This allows for exquisite modulation of Bcl-2's inhibitory properties on IP3Rs that is tunable to the level of IP3 signaling in cells.
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MESH Headings
- Adenosine/analogs & derivatives
- Adenosine/metabolism
- Amino Acid Sequence
- Animals
- Binding, Competitive
- COS Cells
- Calcium Signaling
- Cells, Cultured
- Chlorocebus aethiops
- Inositol 1,4,5-Trisphosphate/metabolism
- Inositol 1,4,5-Trisphosphate Receptors/agonists
- Inositol 1,4,5-Trisphosphate Receptors/antagonists & inhibitors
- Inositol 1,4,5-Trisphosphate Receptors/chemistry
- Inositol 1,4,5-Trisphosphate Receptors/genetics
- Ligands
- Mice
- Molecular Docking Simulation
- Protein Domains
- Proto-Oncogene Proteins c-bcl-2/chemistry
- Proto-Oncogene Proteins c-bcl-2/metabolism
- Sequence Deletion
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Affiliation(s)
- Hristina Ivanova
- Laboratory of Molecular and Cellular Signaling, Department of Cellular and Molecular Medicine, Leuven Cancer Institute (LKI), KU Leuven, Campus Gasthuisberg O/N-1 Bus 802, Herestraat 49, 3000, Leuven, Belgium
| | - Larry E Wagner
- University of Rochester Medical Center School of Medicine and Dentistry, 601 Elmwood Ave, Box 711, Rochester, NY, 14642, USA
| | - Akihiko Tanimura
- Department of Pharmacology, School of Dentistry, Health Sciences University of Hokkaido, Kita-121757 Kanazawa, Ishikari-Tobetsu, Hokkaido, 061-0293, Japan
| | - Elien Vandermarliere
- Center for Medical Biotechnology, VIB-UGent, 9000, Ghent, Belgium
- Department of Biochemistry, Ghent University, 9000, Ghent, Belgium
- Bioinformatics Institute Ghent, Ghent University, 9000, Ghent, Belgium
| | - Tomas Luyten
- Laboratory of Molecular and Cellular Signaling, Department of Cellular and Molecular Medicine, Leuven Cancer Institute (LKI), KU Leuven, Campus Gasthuisberg O/N-1 Bus 802, Herestraat 49, 3000, Leuven, Belgium
| | - Kirsten Welkenhuyzen
- Laboratory of Molecular and Cellular Signaling, Department of Cellular and Molecular Medicine, Leuven Cancer Institute (LKI), KU Leuven, Campus Gasthuisberg O/N-1 Bus 802, Herestraat 49, 3000, Leuven, Belgium
| | - Kamil J Alzayady
- University of Rochester Medical Center School of Medicine and Dentistry, 601 Elmwood Ave, Box 711, Rochester, NY, 14642, USA
| | - Liwei Wang
- University of Rochester Medical Center School of Medicine and Dentistry, 601 Elmwood Ave, Box 711, Rochester, NY, 14642, USA
| | - Kozo Hamada
- Lab Developmental Neurobiology, RIKEN Brain Science Institute, 2-1 Hirosawa Wako-Shi, 351-0198, Saitama, Japan
- SIAIS (Shanghai Institute for Advanced Immunochemical Studies), ShanghaiTech University, 393 Middle Huaxia Road, 201210, Shanghai, China
| | - Katsuhiko Mikoshiba
- Lab Developmental Neurobiology, RIKEN Brain Science Institute, 2-1 Hirosawa Wako-Shi, 351-0198, Saitama, Japan
- SIAIS (Shanghai Institute for Advanced Immunochemical Studies), ShanghaiTech University, 393 Middle Huaxia Road, 201210, Shanghai, China
| | - Humbert De Smedt
- Laboratory of Molecular and Cellular Signaling, Department of Cellular and Molecular Medicine, Leuven Cancer Institute (LKI), KU Leuven, Campus Gasthuisberg O/N-1 Bus 802, Herestraat 49, 3000, Leuven, Belgium
| | - Lennart Martens
- Center for Medical Biotechnology, VIB-UGent, 9000, Ghent, Belgium
- Department of Biochemistry, Ghent University, 9000, Ghent, Belgium
- Bioinformatics Institute Ghent, Ghent University, 9000, Ghent, Belgium
| | - David I Yule
- University of Rochester Medical Center School of Medicine and Dentistry, 601 Elmwood Ave, Box 711, Rochester, NY, 14642, USA
| | - Jan B Parys
- Laboratory of Molecular and Cellular Signaling, Department of Cellular and Molecular Medicine, Leuven Cancer Institute (LKI), KU Leuven, Campus Gasthuisberg O/N-1 Bus 802, Herestraat 49, 3000, Leuven, Belgium
| | - Geert Bultynck
- Laboratory of Molecular and Cellular Signaling, Department of Cellular and Molecular Medicine, Leuven Cancer Institute (LKI), KU Leuven, Campus Gasthuisberg O/N-1 Bus 802, Herestraat 49, 3000, Leuven, Belgium.
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19
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Denizot A, Arizono M, Nägerl UV, Soula H, Berry H. Simulation of calcium signaling in fine astrocytic processes: Effect of spatial properties on spontaneous activity. PLoS Comput Biol 2019; 15:e1006795. [PMID: 31425510 PMCID: PMC6726244 DOI: 10.1371/journal.pcbi.1006795] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2019] [Revised: 09/04/2019] [Accepted: 07/08/2019] [Indexed: 12/20/2022] Open
Abstract
Astrocytes, a glial cell type of the central nervous system, have emerged as detectors and regulators of neuronal information processing. Astrocyte excitability resides in transient variations of free cytosolic calcium concentration over a range of temporal and spatial scales, from sub-microdomains to waves propagating throughout the cell. Despite extensive experimental approaches, it is not clear how these signals are transmitted to and integrated within an astrocyte. The localization of the main molecular actors and the geometry of the system, including the spatial organization of calcium channels IP3R, are deemed essential. However, as most calcium signals occur in astrocytic ramifications that are too fine to be resolved by conventional light microscopy, most of those spatial data are unknown and computational modeling remains the only methodology to study this issue. Here, we propose an IP3R-mediated calcium signaling model for dynamics in such small sub-cellular volumes. To account for the expected stochasticity and low copy numbers, our model is both spatially explicit and particle-based. Extensive simulations show that spontaneous calcium signals arise in the model via the interplay between excitability and stochasticity. The model reproduces the main forms of calcium signals and indicates that their frequency crucially depends on the spatial organization of the IP3R channels. Importantly, we show that two processes expressing exactly the same calcium channels can display different types of calcium signals depending on the spatial organization of the channels. Our model with realistic process volume and calcium concentrations successfully reproduces spontaneous calcium signals that we measured in calcium micro-domains with confocal microscopy and predicts that local variations of calcium indicators might contribute to the diversity of calcium signals observed in astrocytes. To our knowledge, this model is the first model suited to investigate calcium dynamics in fine astrocytic processes and to propose plausible mechanisms responsible for their variability.
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Affiliation(s)
- Audrey Denizot
- INRIA, F-69603, Villeurbanne, France
- Univ Lyon, LIRIS, UMR5205 CNRS, F-69621, Villeurbanne, France
| | - Misa Arizono
- Interdisciplinary Institute for Neuroscience, Université de Bordeaux, Bordeaux, France
- Interdisciplinary Institute for Neuroscience, CNRS UMR 5297, Bordeaux, France
| | - U. Valentin Nägerl
- Interdisciplinary Institute for Neuroscience, Université de Bordeaux, Bordeaux, France
- Interdisciplinary Institute for Neuroscience, CNRS UMR 5297, Bordeaux, France
| | - Hédi Soula
- INRIA, F-69603, Villeurbanne, France
- Univ P&M Curie, CRC, INSERM UMRS 1138, F-75006, Paris, France
| | - Hugues Berry
- INRIA, F-69603, Villeurbanne, France
- Univ Lyon, LIRIS, UMR5205 CNRS, F-69621, Villeurbanne, France
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20
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Bok regulates mitochondrial fusion and morphology. Cell Death Differ 2019; 26:2682-2694. [PMID: 30976095 DOI: 10.1038/s41418-019-0327-4] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2018] [Revised: 03/05/2019] [Accepted: 03/25/2019] [Indexed: 12/11/2022] Open
Abstract
Bok (Bcl-2-related ovarian killer) is a member of the Bcl-2 protein family that governs the intrinsic apoptosis pathway, but the cellular role that Bok plays is controversial. Remarkably, endogenous Bok is constitutively bound to inositol 1,4,5-trisphosphate receptors (IP3Rs) and is stabilized by this interaction. Here we report that despite the strong association with IP3Rs, deletion of Bok expression by CRISPR/Cas9 (clustered regularly interspaced short palindromic repeats/CRISPR-associated protein-9 nuclease)-mediated gene editing does not alter calcium mobilization via IP3Rs or calcium influx into the mitochondria. Rather, Bok deletion significantly reduces mitochondrial fusion rate, resulting in mitochondrial fragmentation. This phenotype is reversed by exogenous wild-type Bok and by an IP3R binding-deficient Bok mutant, and may result from a decrease in mitochondrial motility. Bok deletion also enhances mitochondrial spare respiratory capacity and membrane potential. Finally, Bok does not play a major role in apoptotic signaling, since Bok deletion does not alter responsiveness to various apoptotic stimuli. Overall, despite binding to IP3Rs, Bok does not alter IP3R-mediated Ca2+ signaling, but is required to maintain normal mitochondrial fusion, morphology, and bioenergetics.
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21
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Prole DL, Taylor CW. Structure and Function of IP 3 Receptors. Cold Spring Harb Perspect Biol 2019; 11:cshperspect.a035063. [PMID: 30745293 DOI: 10.1101/cshperspect.a035063] [Citation(s) in RCA: 88] [Impact Index Per Article: 17.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Inositol 1,4,5-trisphosphate receptors (IP3Rs), by releasing Ca2+ from the endoplasmic reticulum (ER) of animal cells, allow Ca2+ to be redistributed from the ER to the cytosol or other organelles, and they initiate store-operated Ca2+ entry (SOCE). For all three IP3R subtypes, binding of IP3 primes them to bind Ca2+, which then triggers channel opening. We are now close to understanding the structural basis of IP3R activation. Ca2+-induced Ca2+ release regulated by IP3 allows IP3Rs to regeneratively propagate Ca2+ signals. The smallest of these regenerative events is a Ca2+ puff, which arises from the nearly simultaneous opening of a small cluster of IP3Rs. Ca2+ puffs are the basic building blocks for all IP3-evoked Ca2+ signals, but only some IP3 clusters, namely those parked alongside the ER-plasma membrane junctions where SOCE occurs, are licensed to respond. The location of these licensed IP3Rs may allow them to selectively regulate SOCE.
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Affiliation(s)
- David L Prole
- Department of Pharmacology, University of Cambridge, Cambridge CB2 1PD, United Kingdom
| | - Colin W Taylor
- Department of Pharmacology, University of Cambridge, Cambridge CB2 1PD, United Kingdom
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22
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Chandran A, Chee X, Prole DL, Rahman T. Exploration of inositol 1,4,5-trisphosphate (IP 3) regulated dynamics of N-terminal domain of IP 3 receptor reveals early phase molecular events during receptor activation. Sci Rep 2019; 9:2454. [PMID: 30792485 PMCID: PMC6385359 DOI: 10.1038/s41598-019-39301-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2018] [Accepted: 01/22/2019] [Indexed: 01/12/2023] Open
Abstract
Inositol 1, 4, 5-trisphosphate (IP3) binding at the N-terminus (NT) of IP3 receptor (IP3R) allosterically triggers the opening of a Ca2+-conducting pore located ~100 Å away from the IP3-binding core (IBC). However, the precise mechanism of IP3 binding and correlated domain dynamics in the NT that are central to the IP3R activation, remains unknown. Our all-atom molecular dynamics (MD) simulations recapitulate the characteristic twist motion of the suppressor domain (SD) and reveal correlated ‘clam closure’ dynamics of IBC with IP3-binding, complementing existing suggestions on IP3R activation mechanism. Our study further reveals the existence of inter-domain dynamic correlation in the NT and establishes the SD to be critical for the conformational dynamics of IBC. Also, a tripartite interaction involving Glu283-Arg54-Asp444 at the SD – IBC interface seemed critical for IP3R activation. Intriguingly, during the sub-microsecond long simulation, we observed Arg269 undergoing an SD-dependent flipping of hydrogen bonding between the first and fifth phosphate groups of IP3. This seems to play a major role in determining the IP3 binding affinity of IBC in the presence/absence of the SD. Our study thus provides atomistic details of early molecular events occurring within the NT during and following IP3 binding that lead to channel gating.
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Affiliation(s)
- Aneesh Chandran
- Department of Pharmacology, University of Cambridge, Tennis Court Road, CB2 1PD, Cambridge, UK. .,Molecular Biophysics Unit, Indian Institute of Science, 560 012, Bangalore, India.
| | - Xavier Chee
- Department of Pharmacology, University of Cambridge, Tennis Court Road, CB2 1PD, Cambridge, UK
| | - David L Prole
- Department of Pharmacology, University of Cambridge, Tennis Court Road, CB2 1PD, Cambridge, UK
| | - Taufiq Rahman
- Department of Pharmacology, University of Cambridge, Tennis Court Road, CB2 1PD, Cambridge, UK.
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23
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Lock JT, Alzayady KJ, Yule DI, Parker I. All three IP 3 receptor isoforms generate Ca 2+ puffs that display similar characteristics. Sci Signal 2018; 11:11/561/eaau0344. [PMID: 30563861 DOI: 10.1126/scisignal.aau0344] [Citation(s) in RCA: 46] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Inositol 1,4,5-trisphosphate (IP3) evokes Ca2+ release through IP3 receptors (IP3Rs) to generate both local Ca2+ puffs arising from concerted openings of clustered IP3Rs and cell-wide Ca2+ waves. Imaging Ca2+ puffs with single-channel resolution yields information on the localization and properties of native IP3Rs in intact cells, but interpretation has been complicated because cells express varying proportions of three structurally and functionally distinct isoforms of IP3Rs. Here, we used TIRF and light-sheet microscopy to image Ca2+ puffs in HEK-293 cell lines generated by CRISPR-Cas9 technology to express exclusively IP3R type 1, 2, or 3. Photorelease of the IP3 analog i-IP3 in all three cell lines evoked puffs with largely similar mean amplitudes, temporal characteristics, and spatial extents. Moreover, the single-channel Ca2+ flux was similar among isoforms, indicating that clusters of different IP3R isoforms contain comparable numbers of active channels. Our results show that all three IP3R isoforms cluster to generate local Ca2+ puffs and, contrary to findings of divergent properties from in vitro electrophysiological studies, display similar conductances and gating kinetics in intact cells.
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Affiliation(s)
- Jeffrey T Lock
- Department of Neurobiology and Behavior, University of California, Irvine, Irvine, CA 92697, USA.
| | - Kamil J Alzayady
- Department of Pharmacology and Physiology, School of Medicine and Dentistry, University of Rochester Medical Center, 601 Elmwood Avenue, Box 711, Rochester, NY 14642, USA
| | - David I Yule
- Department of Pharmacology and Physiology, School of Medicine and Dentistry, University of Rochester Medical Center, 601 Elmwood Avenue, Box 711, Rochester, NY 14642, USA
| | - Ian Parker
- Department of Neurobiology and Behavior, University of California, Irvine, Irvine, CA 92697, USA.,Department of Physiology and Biophysics, University of California, Irvine, Irvine, CA 92697, USA
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24
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Cryo-EM reveals ligand induced allostery underlying InsP 3R channel gating. Cell Res 2018; 28:1158-1170. [PMID: 30470765 PMCID: PMC6274648 DOI: 10.1038/s41422-018-0108-5] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2018] [Revised: 09/02/2018] [Accepted: 10/22/2018] [Indexed: 01/06/2023] Open
Abstract
Inositol-1,4,5-trisphosphate receptors (InsP3Rs) are cation channels that mobilize Ca2+ from intracellular stores in response to a wide range of cellular stimuli. The paradigm of InsP3R activation is the coupled interplay between binding of InsP3 and Ca2+ that switches the ion conduction pathway between closed and open states to enable the passage of Ca2+ through the channel. However, the molecular mechanism of how the receptor senses and decodes ligand-binding signals into gating motion remains unknown. Here, we present the electron cryo-microscopy structure of InsP3R1 from rat cerebellum determined to 4.1 Å resolution in the presence of activating concentrations of Ca2+ and adenophostin A (AdA), a structural mimetic of InsP3 and the most potent known agonist of the channel. Comparison with the 3.9 Å-resolution structure of InsP3R1 in the Apo-state, also reported herein, reveals the binding arrangement of AdA in the tetrameric channel assembly and striking ligand-induced conformational rearrangements within cytoplasmic domains coupled to the dilation of a hydrophobic constriction at the gate. Together, our results provide critical insights into the mechanistic principles by which ligand-binding allosterically gates InsP3R channel.
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25
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Wang JB, Gu Y, Zhang MX, Yang S, Wang Y, Wang W, Li XR, Zhao YT, Wang HT. High expression of type I inositol 1,4,5-trisphosphate receptor in the kidney of rats with hepatorenal syndrome. World J Gastroenterol 2018; 24:3273-3280. [PMID: 30090007 PMCID: PMC6079285 DOI: 10.3748/wjg.v24.i29.3273] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/03/2018] [Revised: 06/19/2018] [Accepted: 06/27/2018] [Indexed: 02/06/2023] Open
Abstract
AIM To detect the expression of type I inositol 1,4,5-trisphosphate receptor (IP3RI) in the kidney of rats with hepatorenal syndrome (HRS). METHODS One hundred and twenty-five Sprague-Dawley rats were randomly divided into four groups to receive an intravenous injection of D-galactosamine (D-GalN) plus lipopolysaccharide (LPS; group G/L, n = 50), D-GalN alone (group G, n = 25), LPS alone (group L, n = 25), and normal saline (group NS, n = 25), respectively. At 3, 6, 9, 12, and 24 h after injection, blood, liver, and kidney samples were collected. Hematoxylin-eosin staining of liver tissue was performed to assess hepatocyte necrosis. Electron microscopy was used to observe ultrastructural changes in the kidney. Western blot analysis and real-time PCR were performed to detect the expression of IP3RI protein and mRNA in the kidney, respectively. RESULTS Hepatocyte necrosis was aggravated gradually, which was most significant at 12 h after treatment with D-galactosamine/lipopolysaccharide, and was characterized by massive hepatocyte necrosis. At the same time, serum levels of biochemical indicators including liver and kidney function indexes were all significantly changed. The structure of the renal glomerulus and tubules was normal at all time points. Western blot analysis indicated that IP3RI protein expression began to rise at 3 h (P < 0.05) and peaked at 12 h (P < 0.01). Real-time PCR demonstrated that IP3RI mRNA expression began to rise at 3 h (P < 0.05) and peaked at 9 h (P < 0.01). CONCLUSION IP3RI protein expression is increased in the kidney of HRS rats, and may be regulated at the transcriptional level.
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MESH Headings
- Animals
- Disease Models, Animal
- Galactosamine/toxicity
- Hepatocytes/pathology
- Hepatorenal Syndrome/chemically induced
- Hepatorenal Syndrome/pathology
- Humans
- Inositol 1,4,5-Trisphosphate Receptors/genetics
- Inositol 1,4,5-Trisphosphate Receptors/metabolism
- Kidney/blood supply
- Kidney/cytology
- Kidney/pathology
- Kidney/ultrastructure
- Lipopolysaccharides/toxicity
- Liver/cytology
- Liver/drug effects
- Liver/pathology
- Male
- Microscopy, Electron
- Muscle, Smooth, Vascular/cytology
- Muscle, Smooth, Vascular/pathology
- Myocytes, Smooth Muscle/pathology
- Myocytes, Smooth Muscle/ultrastructure
- Necrosis
- RNA, Messenger/metabolism
- Rats
- Rats, Sprague-Dawley
- Specific Pathogen-Free Organisms
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Affiliation(s)
- Jing-Bo Wang
- Liver Cirrhosis Ward, the Sixth People’s Hospital of Shenyang, Shenyang 110006, Liaoning Province, China
| | - Ye Gu
- Liver Cirrhosis Ward, the Sixth People’s Hospital of Shenyang, Shenyang 110006, Liaoning Province, China
| | - Ming-Xiang Zhang
- Liver Cirrhosis Ward, the Sixth People’s Hospital of Shenyang, Shenyang 110006, Liaoning Province, China
| | - Shun Yang
- Liaoning Cancer Hospital & Institute, Shenyang 110042, Liaoning Province, China
| | - Yan Wang
- Liver Cirrhosis Ward, the Sixth People’s Hospital of Shenyang, Shenyang 110006, Liaoning Province, China
| | - Wei Wang
- Liver Cirrhosis Ward, the Sixth People’s Hospital of Shenyang, Shenyang 110006, Liaoning Province, China
| | - Xi-Ran Li
- Liver Cirrhosis Ward, the Sixth People’s Hospital of Shenyang, Shenyang 110006, Liaoning Province, China
| | - Yi-Tong Zhao
- Liver Cirrhosis Ward, the Sixth People’s Hospital of Shenyang, Shenyang 110006, Liaoning Province, China
| | - Hai-Tao Wang
- Department of General Surgery, the Second Affiliated Hospital of Shenyang Medical College, Shenyang 110002, Liaoning Province, China
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26
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Wang L, Yule DI. Differential regulation of ion channels function by proteolysis. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2018; 1865:1698-1706. [PMID: 30009861 DOI: 10.1016/j.bbamcr.2018.07.004] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 03/28/2018] [Revised: 07/06/2018] [Accepted: 07/10/2018] [Indexed: 12/23/2022]
Abstract
Ion channels are pore-forming protein complexes in membranes that play essential roles in a diverse array of biological activities. Ion channel activity is strictly regulated at multiple levels and by numerous cellular events to selectively activate downstream effectors involved in specific biological activities. For example, ions, binding proteins, nucleotides, phosphorylation, the redox state, channel subunit composition have all been shown to regulate channel activity and subsequently allow channels to participate in distinct cellular events. While these forms of modulation are well documented and have been extensively reviewed, in this article, we will first review and summarize channel proteolysis as a novel and quite widespread mechanism for altering channel activity. We will then highlight the recent findings demonstrating that proteolysis profoundly alters Inositol 1,4,5 trisphosphate receptor activity, and then discuss its potential functional ramifications in various developmental and pathological conditions.
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Affiliation(s)
- Liwei Wang
- Department of Pharmacology and Physiology, University of Rochester, Rochester, NY 14642, United States of America
| | - David I Yule
- Department of Pharmacology and Physiology, University of Rochester, Rochester, NY 14642, United States of America.
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27
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Wang L, Wagner LE, Alzayady KJ, Yule DI. Region-specific proteolysis differentially modulates type 2 and type 3 inositol 1,4,5-trisphosphate receptor activity in models of acute pancreatitis. J Biol Chem 2018; 293:13112-13124. [PMID: 29970616 DOI: 10.1074/jbc.ra118.003421] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2018] [Revised: 06/04/2018] [Indexed: 12/22/2022] Open
Abstract
Fine-tuning of the activity of inositol 1,4,5-trisphosphate receptors (IP3R) by a diverse array of regulatory inputs results in intracellular Ca2+ signals with distinct characteristics. These events allow the activation of specific downstream effectors. We reported previously that region-specific proteolysis represents a novel regulatory event for type 1 IP3R (R1). Specifically, caspase-fragmented R1 display a marked increase in single-channel open probability. More importantly, the distinct characteristics of the Ca2+ signals elicited via fragmented R1 can activate alternate downstream effectors. In this report, we expand these studies to investigate whether all IP3R subtypes are regulated by proteolysis. We now show that type 2 and type 3 IP3R (R2 and R3, respectively) are proteolytically cleaved in rodent models of acute pancreatitis. Surprisingly, fragmented IP3R retained tetrameric architecture, remained embedded in endoplasmic reticulum membranes and were not functionally disabled. Proteolysis was associated with a marked attenuation of the frequency of Ca2+ signals in pancreatic lobules. Consistent with these data, expression of DNAs encoding complementary R2 and R3 peptides mimicking fragmented receptors at particular sites, resulted in a significant decrease in the frequency of agonist-stimulated Ca2+ oscillations. Further, proteolysis of R2 resulted in a marked decrease in single-channel open probability. Taken together, proteolytic fragmentation modulates R2 and R3 activity in a region-specific manner, and this event may contribute to the altered Ca2+ signals in pancreatic acinar cells during acute pancreatitis.
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Affiliation(s)
- Liwei Wang
- From the Department of Pharmacology and Physiology, University of Rochester, Rochester, New York 14642
| | - Larry E Wagner
- From the Department of Pharmacology and Physiology, University of Rochester, Rochester, New York 14642
| | - Kamil J Alzayady
- From the Department of Pharmacology and Physiology, University of Rochester, Rochester, New York 14642
| | - David I Yule
- From the Department of Pharmacology and Physiology, University of Rochester, Rochester, New York 14642
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28
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Williams JA, Yule DI. Can pancreatitis be treated by inhibiting Ca 2+ signaling? ANNALS OF TRANSLATIONAL MEDICINE 2018; 6:124. [PMID: 29955584 DOI: 10.21037/atm.2017.06.07] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Affiliation(s)
- John A Williams
- Departments of Molecular and Integrative Physiology and Internal Medicine, University of Michigan, Ann Arbor, MI, USA
| | - David I Yule
- Department of Pharmacology and Physiology, University of Rochester, Rochester, NY, USA
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29
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Ivanova H, Ritaine A, Wagner L, Luyten T, Shapovalov G, Welkenhuyzen K, Seitaj B, Monaco G, De Smedt H, Prevarskaya N, Yule DI, Parys JB, Bultynck G. The trans-membrane domain of Bcl-2α, but not its hydrophobic cleft, is a critical determinant for efficient IP3 receptor inhibition. Oncotarget 2018; 7:55704-55720. [PMID: 27494888 PMCID: PMC5342447 DOI: 10.18632/oncotarget.11005] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2016] [Accepted: 07/18/2016] [Indexed: 12/29/2022] Open
Abstract
The anti-apoptotic Bcl-2 protein is emerging as an efficient inhibitor of IP3R function, contributing to its oncogenic properties. Yet, the underlying molecular mechanisms remain not fully understood. Using mutations or pharmacological inhibition to antagonize Bcl-2's hydrophobic cleft, we excluded this functional domain as responsible for Bcl-2-mediated IP3Rs inhibition. In contrast, the deletion of the C-terminus, containing the trans-membrane domain, which is only present in Bcl-2α, but not in Bcl-2β, led to impaired inhibition of IP3R-mediated Ca2+ release and staurosporine-induced apoptosis. Strikingly, the trans-membrane domain was sufficient for IP3R binding and inhibition. We therefore propose a novel model, in which the Bcl-2's C-terminus serves as a functional anchor, which beyond mere ER-membrane targeting, underlies efficient IP3R inhibition by (i) positioning the BH4 domain in the close proximity of its binding site on IP3R, thus facilitating their interaction; (ii) inhibiting IP3R-channel openings through a direct interaction with the C-terminal region of the channel downstream of the channel-pore. Finally, since the hydrophobic cleft of Bcl-2 was not involved in IP3R suppression, our findings indicate that ABT-199 does not interfere with IP3R regulation by Bcl-2 and its mechanism of action as a cell-death therapeutic in cancer cells likely does not involve Ca2+ signaling.
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Affiliation(s)
- Hristina Ivanova
- Katholieke Universiteit Leuven, Laboratory of Molecular and Cellular Signaling, Department of Cellular and Molecular Medicine and Leuven Cancer Institute (LKI), BE-3000 Leuven, Belgium
| | - Abigael Ritaine
- Inserm U-1003, Equipe Labellisée par la Ligue Nationale Contre le Cancer et LABEX (Laboratoire d'excellence), Université Lille1, 59655 Villeneuve d'Ascq, France
| | - Larry Wagner
- University of Rochester Medical Center School of Medicine and Dentistry, Rochester, NY 14642, USA
| | - Tomas Luyten
- Katholieke Universiteit Leuven, Laboratory of Molecular and Cellular Signaling, Department of Cellular and Molecular Medicine and Leuven Cancer Institute (LKI), BE-3000 Leuven, Belgium
| | - George Shapovalov
- Inserm U-1003, Equipe Labellisée par la Ligue Nationale Contre le Cancer et LABEX (Laboratoire d'excellence), Université Lille1, 59655 Villeneuve d'Ascq, France
| | - Kirsten Welkenhuyzen
- Katholieke Universiteit Leuven, Laboratory of Molecular and Cellular Signaling, Department of Cellular and Molecular Medicine and Leuven Cancer Institute (LKI), BE-3000 Leuven, Belgium
| | - Bruno Seitaj
- Katholieke Universiteit Leuven, Laboratory of Molecular and Cellular Signaling, Department of Cellular and Molecular Medicine and Leuven Cancer Institute (LKI), BE-3000 Leuven, Belgium
| | - Giovanni Monaco
- Katholieke Universiteit Leuven, Laboratory of Molecular and Cellular Signaling, Department of Cellular and Molecular Medicine and Leuven Cancer Institute (LKI), BE-3000 Leuven, Belgium
| | - Humbert De Smedt
- Katholieke Universiteit Leuven, Laboratory of Molecular and Cellular Signaling, Department of Cellular and Molecular Medicine and Leuven Cancer Institute (LKI), BE-3000 Leuven, Belgium
| | - Natalia Prevarskaya
- Inserm U-1003, Equipe Labellisée par la Ligue Nationale Contre le Cancer et LABEX (Laboratoire d'excellence), Université Lille1, 59655 Villeneuve d'Ascq, France
| | - David I Yule
- University of Rochester Medical Center School of Medicine and Dentistry, Rochester, NY 14642, USA
| | - Jan B Parys
- Katholieke Universiteit Leuven, Laboratory of Molecular and Cellular Signaling, Department of Cellular and Molecular Medicine and Leuven Cancer Institute (LKI), BE-3000 Leuven, Belgium
| | - Geert Bultynck
- Katholieke Universiteit Leuven, Laboratory of Molecular and Cellular Signaling, Department of Cellular and Molecular Medicine and Leuven Cancer Institute (LKI), BE-3000 Leuven, Belgium
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30
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Toglia P, Ullah G, Pearson JE. Analyzing optical imaging of Ca 2+ signals via TIRF microscopy: The limits on resolution due to chemical rates and depth of the channels. Cell Calcium 2017; 67:65-73. [PMID: 29029792 DOI: 10.1016/j.ceca.2017.08.010] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2017] [Revised: 08/22/2017] [Accepted: 08/23/2017] [Indexed: 11/17/2022]
Abstract
High resolution total internal reflection (TIRF) microscopy (TIRFM) together with detailed computational modeling provides a powerful approach towards the understanding of a wide range of Ca2+ signals mediated by the ubiquitous inositol 1,4,5-trisphosphate (IP3) receptor (IP3R) channel. Exploiting this fruitful collaboration further requires close agreement between the models and observations. However, elementary Ca2+ release events, puffs, imaged through TIRFM do not show the rapid single-channel openings and closings during and between puffs as are present in simulated puffs using data-driven single channel models. TIRFM also shows a rapid equilibration of 10ms after a channel opens or closes which is not achievable in simulation using standard Ca2+ diffusion coefficients and reaction rates between indicator dye and Ca2+. Furthermore, TIRFM imaging cannot decipher the depth of the channel with respect to the microscope, which will affect the change in fluorescence that the microscope detects, thereby affecting its sensitivity to fast single-channel activity. Using the widely used Ca2+ diffusion coefficients and reaction rates, our simulations show equilibration rates that are eight times slower than TIRFM imaging. We show that to get equilibrium rates consistent with observed values, the diffusion coefficients and reaction rates have to be significantly higher than the values reported in the literature, and predict the channel depth to be 200-250nm. Finally, we show that with the addition of noise, short events due to 1-2ms opening and closing of channels that are observed in computational models can be missed in TIRFM.
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Affiliation(s)
- Patrick Toglia
- Department of Physics, University of South Florida, Tampa, FL 33620, USA
| | - Ghanim Ullah
- Department of Physics, University of South Florida, Tampa, FL 33620, USA.
| | - John E Pearson
- T-6 Theoretical Biology and Biophysics Division, Los Alamos National Laboratory, Los Alamos, NM 87545, USA
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31
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Cao P, Falcke M, Sneyd J. Mapping Interpuff Interval Distribution to the Properties of Inositol Trisphosphate Receptors. Biophys J 2017; 112:2138-2146. [PMID: 28538151 DOI: 10.1016/j.bpj.2017.03.019] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2017] [Revised: 03/14/2017] [Accepted: 03/24/2017] [Indexed: 01/24/2023] Open
Abstract
Tightly clustered inositol trisphosphate receptors (IP3Rs) control localized Ca2+ liberation from the endoplasmic reticulum to generate repetitive Ca2+ puffs. Distributions of the interpuff interval (IPI), i.e., the waiting time between successive puffs, are found to be well characterized by a probability density function involving only two parameters, λ and ξ, which represent the basal rate of puff generation and the recovery rate from refractoriness, respectively. However, how the two parameters depend on the kinetic parameters of single IP3Rs in a cluster is still unclear. In this article, using a stochastic puff model and a single-channel data-based IP3R model, we establish the dependencies of λ and ξ on two important IP3R model parameters, IP3 concentration ([IP3]) and the recovery rate from Ca2+ inhibition (rlow). By varying [IP3] and rlow in physiologically plausible ranges, we find that the ξ-λ plane is comprised of only two disjoint regions, a biologically impermissible region and a region where each parameter set (ξ, λ) can be caused by using two different combinations of [IP3] and rlow. The two combinations utilize very different mechanisms to maintain the same IPI distribution, and the mechanistic difference provides a way of identifying IP3R kinetic parameters by observing properties of the IPI.
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Affiliation(s)
- Pengxing Cao
- School of Mathematics and Statistics, The University of Melbourne, Melbourne, Victoria, Australia
| | - Martin Falcke
- Mathematical Cell Physiology, Max Delbrück Center for Molecular Medicine, Berlin, Germany
| | - James Sneyd
- Department of Mathematics, The University of Auckland, Auckland, New Zealand.
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Wang L, Wagner LE, Alzayady KJ, Yule DI. Region-specific proteolysis differentially regulates type 1 inositol 1,4,5-trisphosphate receptor activity. J Biol Chem 2017; 292:11714-11726. [PMID: 28526746 DOI: 10.1074/jbc.m117.789917] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2017] [Revised: 05/11/2017] [Indexed: 12/31/2022] Open
Abstract
The inositol 1,4,5 trisphosphate receptor (IP3R) is an intracellular Ca2+ release channel expressed predominately on the membranes of the endoplasmic reticulum. IP3R1 can be cleaved by caspase or calpain into at least two receptor fragments. However, the functional consequences of receptor fragmentation are poorly understood. Our previous work has demonstrated that IP3R1 channels, formed following either enzymatic fragmentation or expression of the corresponding complementary polypeptide chains, retain tetrameric architecture and are still activated by IP3 binding despite the loss of peptide continuity. In this study, we demonstrate that region-specific receptor fragmentation modifies channel regulation. Specifically, the agonist-evoked temporal Ca2+ release profile and protein kinase A modulation of Ca2+ release are markedly altered. Moreover, we also demonstrate that activation of fragmented IP3R1 can result in a distinct functional outcome. Our work suggests that proteolysis of IP3R1 may represent a novel form of modulation of IP3R1 channel function and increases the repertoire of Ca2+ signals achievable through this channel.
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Affiliation(s)
- Liwei Wang
- Department of Pharmacology and Physiology, University of Rochester, Rochester, New York 14642
| | - Larry E Wagner
- Department of Pharmacology and Physiology, University of Rochester, Rochester, New York 14642
| | - Kamil J Alzayady
- Department of Pharmacology and Physiology, University of Rochester, Rochester, New York 14642
| | - David I Yule
- Department of Pharmacology and Physiology, University of Rochester, Rochester, New York 14642.
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33
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Nurbaeva MK, Eckstein M, Feske S, Lacruz RS. Ca 2+ transport and signalling in enamel cells. J Physiol 2017; 595:3015-3039. [PMID: 27510811 PMCID: PMC5430215 DOI: 10.1113/jp272775] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2016] [Accepted: 07/21/2016] [Indexed: 01/02/2023] Open
Abstract
Dental enamel is one of the most remarkable examples of matrix-mediated biomineralization. Enamel crystals form de novo in a rich extracellular environment in a stage-dependent manner producing complex microstructural patterns that are visually stunning. This process is orchestrated by specialized epithelial cells known as ameloblasts which themselves undergo striking morphological changes, switching function from a secretory role to a cell primarily engaged in ionic transport. Ameloblasts are supported by a host of cell types which combined represent the enamel organ. Fully mineralized enamel is the hardest tissue found in vertebrates owing its properties partly to the unique mixture of ionic species represented and their highly organized assembly in the crystal lattice. Among the main elements found in enamel, Ca2+ is the most abundant ion, yet how ameloblasts modulate Ca2+ dynamics remains poorly known. This review describes previously proposed models for passive and active Ca2+ transport, the intracellular Ca2+ buffering systems expressed in ameloblasts and provides an up-dated view of current models concerning Ca2+ influx and extrusion mechanisms, where most of the recent advances have been made. We also advance a new model for Ca2+ transport by the enamel organ.
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Affiliation(s)
- Meerim K. Nurbaeva
- Department of Basic Science and Craniofacial BiologyNew York University College of DentistryNew YorkUSA
| | - Miriam Eckstein
- Department of Basic Science and Craniofacial BiologyNew York University College of DentistryNew YorkUSA
| | - Stefan Feske
- Department of PathologyNew York University School of MedicineNew YorkNY10016USA
| | - Rodrigo S. Lacruz
- Department of Basic Science and Craniofacial BiologyNew York University College of DentistryNew YorkUSA
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Tykocki NR, Boerman EM, Jackson WF. Smooth Muscle Ion Channels and Regulation of Vascular Tone in Resistance Arteries and Arterioles. Compr Physiol 2017; 7:485-581. [PMID: 28333380 DOI: 10.1002/cphy.c160011] [Citation(s) in RCA: 222] [Impact Index Per Article: 31.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Vascular tone of resistance arteries and arterioles determines peripheral vascular resistance, contributing to the regulation of blood pressure and blood flow to, and within the body's tissues and organs. Ion channels in the plasma membrane and endoplasmic reticulum of vascular smooth muscle cells (SMCs) in these blood vessels importantly contribute to the regulation of intracellular Ca2+ concentration, the primary determinant of SMC contractile activity and vascular tone. Ion channels provide the main source of activator Ca2+ that determines vascular tone, and strongly contribute to setting and regulating membrane potential, which, in turn, regulates the open-state-probability of voltage gated Ca2+ channels (VGCCs), the primary source of Ca2+ in resistance artery and arteriolar SMCs. Ion channel function is also modulated by vasoconstrictors and vasodilators, contributing to all aspects of the regulation of vascular tone. This review will focus on the physiology of VGCCs, voltage-gated K+ (KV) channels, large-conductance Ca2+-activated K+ (BKCa) channels, strong-inward-rectifier K+ (KIR) channels, ATP-sensitive K+ (KATP) channels, ryanodine receptors (RyRs), inositol 1,4,5-trisphosphate receptors (IP3Rs), and a variety of transient receptor potential (TRP) channels that contribute to pressure-induced myogenic tone in resistance arteries and arterioles, the modulation of the function of these ion channels by vasoconstrictors and vasodilators, their role in the functional regulation of tissue blood flow and their dysfunction in diseases such as hypertension, obesity, and diabetes. © 2017 American Physiological Society. Compr Physiol 7:485-581, 2017.
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Affiliation(s)
- Nathan R Tykocki
- Department of Pharmacology, University of Vermont, Burlington, Vermont, USA
| | - Erika M Boerman
- Department of Medical Pharmacology and Physiology, University of Missouri, Columbia, Missouri, USA
| | - William F Jackson
- Department of Pharmacology and Toxicology, Michigan State University, East Lansing, Michigan, USA
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Garcia MI, Boehning D. Cardiac inositol 1,4,5-trisphosphate receptors. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2016; 1864:907-914. [PMID: 27884701 DOI: 10.1016/j.bbamcr.2016.11.017] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/01/2016] [Revised: 11/16/2016] [Accepted: 11/16/2016] [Indexed: 10/20/2022]
Abstract
Calcium is a second messenger that regulates almost all cellular functions. In cardiomyocytes, calcium plays an integral role in many functions including muscle contraction, gene expression, and cell death. Inositol 1,4,5-trisphosphate receptors (IP3Rs) are a family of calcium channels that are ubiquitously expressed in all tissues. In the heart, IP3Rs have been associated with regulation of cardiomyocyte function in response to a variety of neurohormonal agonists, including those implicated in cardiac disease. Notably, IP3R activity is thought to be essential for mediating the hypertrophic response to multiple stimuli including endothelin-1 and angiotensin II. In this review, we will explore the functional implications of IP3R activity in the heart in health and disease.
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Affiliation(s)
- M Iveth Garcia
- Cell Biology Graduate Program, University of Texas Medical Branch, Galveston, TX 77555, United States; Department of Biochemistry and Molecular Biology, McGovern Medical School at UTHealth, Houston, TX 77030, United States
| | - Darren Boehning
- Department of Biochemistry and Molecular Biology, McGovern Medical School at UTHealth, Houston, TX 77030, United States.
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Structural and dynamic insights into the subtype-specific IP3-binding mechanism of the IP3 receptor. Biochem J 2016; 473:3533-3543. [DOI: 10.1042/bcj20160539] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2016] [Accepted: 07/21/2016] [Indexed: 11/17/2022]
Abstract
There are three subtypes of vertebrate inositol 1,4,5-trisphosphate (IP3) receptor (IP3R), a Ca2+-release channel on the ER membrane — IP3R1, IP3R2, and IP3R3 — each of which has a distinctive role in disease development. To determine the subtype-specific IP3-binding mechanism, we compared the thermodynamics, thermal stability, and conformational dynamics between the N-terminal regions of IP3R1 (IP3R1-NT) and IP3R3 (IP3R3-NT) by performing circular dichroism (CD), isothermal titration calorimetry (ITC), and hydrogen–deuterium exchange mass spectrometry (HDX-MS). Previously determined crystal structures of IP3R1-NT and HDX-MS results from this study revealed that both IP3R1 and IP3R3 adopt a similar IP3-binding mechanism. However, several regions, including the α- and β-interfaces, of IP3R1-NT and IP3R3-NT show significantly different conformational dynamics upon IP3 binding, which may explain the different IP3-binding affinities between the subtypes. The importance of the interfaces for subtype-specific IP3 binding is also supported by the different dynamic conformations of the two subtypes in the apo-states. Furthermore, IP3R1-NT and IP3R3-NT show different IP3-binding affinities and thermal stabilities, but share similar thermodynamic properties for IP3 binding. These results collectively provide new insights into the mechanism underlying IP3 binding to IP3Rs and the subtype-specific regulatory mechanism.
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Boie S, Chen J, Sanderson MJ, Sneyd J. The relative contributions of store-operated and voltage-gated Ca 2+ channels to the control of Ca 2+ oscillations in airway smooth muscle. J Physiol 2016; 595:3129-3141. [PMID: 27502470 DOI: 10.1113/jp272996] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2016] [Accepted: 08/03/2016] [Indexed: 02/02/2023] Open
Abstract
KEY POINTS Agonist-dependent oscillations in the concentration of free cytosolic calcium are a vital mechanism for the control of airway smooth muscle contraction and thus are a critical factor in airway hyper-responsiveness. Using a mathematical model, closely tied to experimental work, we show that the oscillations in membrane potential accompanying the calcium oscillations have no significant effect on the properties of the calcium oscillations. In addition, the model shows that calcium entry through store-operated calcium channels is critical for calcium oscillations, but calcium entry through voltage-gated channels has much less effect. The model predicts that voltage-gated channels are less important than store-operated channels in the control of airway smooth muscle tone. ABSTRACT Airway smooth muscle contraction is typically the key mechanism underlying airway hyper-responsiveness, and the strength of muscle contraction is determined by the frequency of oscillations of intracellular calcium (Ca2+ ) concentration. In airway smooth muscle cells, these Ca2+ oscillations are caused by cyclic Ca2+ release from the sarcoplasmic reticulum, although Ca2+ influx via plasma membrane channels is also necessary to sustain the oscillations over longer times. To assess the relative contributions of store-operated and voltage-gated Ca2+ channels to this Ca2+ influx, we generated a comprehensive mathematical model, based on experimental Ca2+ measurements in mouse precision-cut lung slices, to simulate Ca2+ oscillations and changes in membrane potential. Agonist-induced Ca2+ oscillations are accompanied by oscillations in membrane potential, although the membrane potential oscillations are too small to generate large Ca2+ currents through voltage-gated Ca2+ channels, and thus have little effect on the Ca2+ oscillations. Ca2+ entry through voltage-gated channels only becomes important when the cell is depolarized (e.g. by a high external K+ concentration). As a result, agonist-induced Ca2+ oscillations are critically dependent on Ca2+ entry through store-operated channels but do not depend strongly on Ca2+ entry though voltage-gated channels.
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Affiliation(s)
- Sebastian Boie
- Department of Mathematics, The University of Auckland, Auckland, New Zealand
| | - Jun Chen
- Department of Microbiology and Physiological Systems, University of Massachusetts Medical School, Worcester, MA, USA
| | - Michael J Sanderson
- Department of Microbiology and Physiological Systems, University of Massachusetts Medical School, Worcester, MA, USA
| | - James Sneyd
- Department of Mathematics, The University of Auckland, Auckland, New Zealand
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38
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Emergence of ion channel modal gating from independent subunit kinetics. Proc Natl Acad Sci U S A 2016; 113:E5288-97. [PMID: 27551100 DOI: 10.1073/pnas.1604090113] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Many ion channels exhibit a slow stochastic switching between distinct modes of gating activity. This feature of channel behavior has pronounced implications for the dynamics of ionic currents and the signaling pathways that they regulate. A canonical example is the inositol 1,4,5-trisphosphate receptor (IP3R) channel, whose regulation of intracellular Ca(2+) concentration is essential for numerous cellular processes. However, the underlying biophysical mechanisms that give rise to modal gating in this and most other channels remain unknown. Although ion channels are composed of protein subunits, previous mathematical models of modal gating are coarse grained at the level of whole-channel states, limiting further dialogue between theory and experiment. Here we propose an origin for modal gating, by modeling the kinetics of ligand binding and conformational change in the IP3R at the subunit level. We find good agreement with experimental data over a wide range of ligand concentrations, accounting for equilibrium channel properties, transient responses to changing ligand conditions, and modal gating statistics. We show how this can be understood within a simple analytical framework and confirm our results with stochastic simulations. The model assumes that channel subunits are independent, demonstrating that cooperative binding or concerted conformational changes are not required for modal gating. Moreover, the model embodies a generally applicable principle: If a timescale separation exists in the kinetics of individual subunits, then modal gating can arise as an emergent property of channel behavior.
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Horiuchi K, Tohmonda T, Morioka H. The unfolded protein response in skeletal development and homeostasis. Cell Mol Life Sci 2016; 73:2851-69. [PMID: 27002737 PMCID: PMC11108572 DOI: 10.1007/s00018-016-2178-1] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2016] [Revised: 03/06/2016] [Accepted: 03/10/2016] [Indexed: 12/20/2022]
Abstract
Osteoblasts and chondrocytes produce a large number of extracellular matrix proteins to generate and maintain the skeletal system. To cope with their functions as secretory cells, these cells must acquire a considerable capacity for protein synthesis and also the machinery for the quality-control and transport of newly synthesized secreted proteins. The unfolded protein response (UPR) plays a crucial role during the differentiation of these cells to achieve this goal. Unexpectedly, however, studies in the past several years have revealed that the UPR has more extensive functions in skeletal development than was initially assumed, and the UPR critically orchestrates many facets of skeletal development and homeostasis. This review focuses on recent findings on the functions of the UPR in the differentiation of osteoblasts, chondrocytes, and osteoclasts. These findings may have a substantial impact on our understanding of bone metabolism and also on establishing treatments for congenital and acquired skeletal disorders.
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Affiliation(s)
- Keisuke Horiuchi
- Department of Orthopedic Surgery, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ku, Tokyo, 160-8582, Japan.
- Department of Anti-aging Orthopedic Research, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ku, Tokyo, 160-8582, Japan.
| | - Takahide Tohmonda
- Department of Orthopedic Surgery, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ku, Tokyo, 160-8582, Japan
- Department of Anti-aging Orthopedic Research, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ku, Tokyo, 160-8582, Japan
| | - Hideo Morioka
- Department of Orthopedic Surgery, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ku, Tokyo, 160-8582, Japan
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40
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Siekmann I, Fackrell M, Crampin EJ, Taylor P. Modelling modal gating of ion channels with hierarchical Markov models. Proc Math Phys Eng Sci 2016; 472:20160122. [PMID: 27616917 PMCID: PMC5014102 DOI: 10.1098/rspa.2016.0122] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2016] [Accepted: 07/22/2016] [Indexed: 11/12/2022] Open
Abstract
Many ion channels spontaneously switch between different levels of activity. Although this behaviour known as modal gating has been observed for a long time it is currently not well understood. Despite the fact that appropriately representing activity changes is essential for accurately capturing time course data from ion channels, systematic approaches for modelling modal gating are currently not available. In this paper, we develop a modular approach for building such a model in an iterative process. First, stochastic switching between modes and stochastic opening and closing within modes are represented in separate aggregated Markov models. Second, the continuous-time hierarchical Markov model, a new modelling framework proposed here, then enables us to combine these components so that in the integrated model both mode switching as well as the kinetics within modes are appropriately represented. A mathematical analysis reveals that the behaviour of the hierarchical Markov model naturally depends on the properties of its components. We also demonstrate how a hierarchical Markov model can be parametrized using experimental data and show that it provides a better representation than a previous model of the same dataset. Because evidence is increasing that modal gating reflects underlying molecular properties of the channel protein, it is likely that biophysical processes are better captured by our new approach than in earlier models.
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Affiliation(s)
- Ivo Siekmann
- Systems Biology Laboratory, Melbourne School of Engineering, University of Melbourne, Melbourne, Australia
- Centre for Systems Genomics, University of Melbourne, Melbourne, Australia
| | - Mark Fackrell
- School of Mathematics and Statistics, University of Melbourne, Melbourne, Australia
| | - Edmund J. Crampin
- Systems Biology Laboratory, Melbourne School of Engineering, University of Melbourne, Melbourne, Australia
- Centre for Systems Genomics, University of Melbourne, Melbourne, Australia
- School of Mathematics and Statistics, University of Melbourne, Melbourne, Australia
- School of Medicine, University of Melbourne, Melbourne, Australia
- Australian Research Council Centre of Excellence in Convergent Bio-Nano Science and Technology, Melbourne, Australia
| | - Peter Taylor
- School of Mathematics and Statistics, University of Melbourne, Melbourne, Australia
- Australian Research Council Centre of Excellence for Mathematical and Statistical Frontiers, Melbourne, Australia
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41
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Sneyd J, Means S, Zhu D, Rugis J, Won JH, Yule DI. Modeling calcium waves in an anatomically accurate three-dimensional parotid acinar cell. J Theor Biol 2016; 419:383-393. [PMID: 27155044 DOI: 10.1016/j.jtbi.2016.04.030] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2016] [Revised: 04/20/2016] [Accepted: 04/25/2016] [Indexed: 11/24/2022]
Abstract
We construct a model of calcium waves in a three-dimensional anatomically accurate parotid acinar cell, constructed from experimental data. Gradients of inositol trisphosphate receptor (IPR) density are imposed, with the IPR density being greater closer to the lumen, which has a branched structure, and inositol trisphosphate (IP3) is produced only at the basal membrane. We show (1) that IP3 equilibrates so quickly across the cell that it can be assumed to be spatially homogeneous; (2) spatial separation of the sites of IP3 action and IP3 production does not preclude the formation of stable oscillatory Ca2+ waves. However, these waves are not waves in the mathematical sense of a traveling wave with fixed profile. They result instead from a time delay between the Ca2+ rise in the apical and basal regions; (3) the ryanodine receptors serve to reinforce the Ca2+ wave, but are not necessary for the wave to exist; (4) a spatially independent model is not sufficient to study saliva secretion, although a one-dimensional model might be sufficient. Our results here form the first stages of the construction of a multiscale and multicellular model of saliva secretion in an entire acinus.
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Affiliation(s)
- James Sneyd
- Department of Mathematics, University of Auckland, New Zealand.
| | - Shawn Means
- Department of Mathematics, University of Auckland, New Zealand
| | - Di Zhu
- Department of Mathematics, University of Auckland, New Zealand
| | - John Rugis
- Department of Mathematics, University of Auckland, New Zealand
| | - Jong Hak Won
- Department of Pharmacology and Physiology, University of Rochester Medical Centre, Rochester, USA
| | - David I Yule
- Department of Pharmacology and Physiology, University of Rochester Medical Centre, Rochester, USA
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42
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Alzayady KJ, Wang L, Chandrasekhar R, Wagner LE, Van Petegem F, Yule DI. Defining the stoichiometry of inositol 1,4,5-trisphosphate binding required to initiate Ca2+ release. Sci Signal 2016; 9:ra35. [PMID: 27048566 DOI: 10.1126/scisignal.aad6281] [Citation(s) in RCA: 124] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Inositol 1,4,5-trisphosphate (IP3) receptors (IP3Rs) are tetrameric intracellular Ca(2+)-release channels with each subunit containing a binding site for IP3in the amino terminus. We provide evidence that four IP3molecules are required to activate the channel under diverse conditions. Comparing the concentration-response relationship for binding and Ca(2+)release suggested that IP3Rs are maximally occupied by IP3before substantial Ca(2+)release occurs. We showed that ligand binding-deficient subunits acted in a dominant-negative manner when coexpressed with wild-type monomers in the chicken immune cell line DT40-3KO, which lacks all three genes encoding IP3R subunits, and confirmed the same effect in an IP3R-null human cell line (HEK-3KO) generated by CRISPR/Cas9 technology. Using dimeric and tetrameric concatenated IP3Rs with increasing numbers of binding-deficient subunits, we addressed the obligate ligand stoichiometry. The concatenated IP3Rs with four ligand-binding sites exhibited Ca(2+)release and electrophysiological properties of native IP3Rs. However, IP3failed to activate IP3Rs assembled from concatenated dimers consisting of one binding-competent and one binding-deficient mutant subunit. Similarly, IP3Rs containing two monomers of IP3R2short, an IP3binding-deficient splice variant, were nonfunctional. Concatenated tetramers containing only three binding-competent ligand-binding sites were nonfunctional under a wide range of activating conditions. These data provide definitive evidence that IP3-induced Ca(2+)release only occurs when each IP3R monomer within the tetramer is occupied by IP3, thereby ensuring fidelity of Ca(2+)release.
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Affiliation(s)
- Kamil J Alzayady
- Department of Pharmacology and Physiology, University of Rochester, Rochester, NY 14642, USA
| | - Liwei Wang
- Department of Pharmacology and Physiology, University of Rochester, Rochester, NY 14642, USA
| | - Rahul Chandrasekhar
- Department of Pharmacology and Physiology, University of Rochester, Rochester, NY 14642, USA
| | - Larry E Wagner
- Department of Pharmacology and Physiology, University of Rochester, Rochester, NY 14642, USA
| | - Filip Van Petegem
- Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, British Columbia V6T 1Z3, Canada
| | - David I Yule
- Department of Pharmacology and Physiology, University of Rochester, Rochester, NY 14642, USA.
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Chandrasekhar R, Alzayady KJ, Wagner LE, Yule DI. Unique Regulatory Properties of Heterotetrameric Inositol 1,4,5-Trisphosphate Receptors Revealed by Studying Concatenated Receptor Constructs. J Biol Chem 2016; 291:4846-60. [PMID: 26755721 DOI: 10.1074/jbc.m115.705301] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2015] [Indexed: 02/02/2023] Open
Abstract
The ability of inositol 1,4,5-trisphosphate receptors (IP3R) to precisely initiate and generate a diverse variety of intracellular Ca(2+) signals is in part mediated by the differential regulation of the three subtypes (R1, R2, and R3) by key functional modulators (IP3, Ca(2+), and ATP). However, the contribution of IP3R heterotetramerization to Ca(2+) signal diversity has largely been unexplored. In this report, we provide the first definitive biochemical evidence of endogenous heterotetramer formation. Additionally, we examine the contribution of individual subtypes within defined concatenated heterotetramers to the shaping of Ca(2+) signals. Under conditions where key regulators of IP3R function are optimal for Ca(2+) release, we demonstrate that individual monomers within heteromeric IP3Rs contributed equally toward generating a distinct 'blended' sensitivity to IP3 that is likely dictated by the unique IP3 binding affinity of the heteromers. However, under suboptimal conditions where [ATP] were varied, we found that one subtype dictated the ATP regulatory properties of heteromers. We show that R2 monomers within a heterotetramer were both necessary and sufficient to dictate the ATP regulatory properties. Finally, the ATP-binding site B in R2 critical for ATP regulation was mutated and rendered non-functional to address questions relating to the stoichiometry of IP3R regulation. Two intact R2 monomers were sufficient to maintain ATP regulation in R2 homotetramers. In summary, we demonstrate that heterotetrameric IP3R do not necessarily behave as the sum of the constituent subunits, and these properties likely extend the versatility of IP3-induced Ca(2+) signaling in cells expressing multiple IP3R isoforms.
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Affiliation(s)
- Rahul Chandrasekhar
- From the Department of Pharmacology and Physiology, University of Rochester, Rochester, New York 14642
| | - Kamil J Alzayady
- From the Department of Pharmacology and Physiology, University of Rochester, Rochester, New York 14642
| | - Larry E Wagner
- From the Department of Pharmacology and Physiology, University of Rochester, Rochester, New York 14642
| | - David I Yule
- From the Department of Pharmacology and Physiology, University of Rochester, Rochester, New York 14642
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44
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Kim HN, Seok SH, Chung KY, Won HS, Son WS, Seo MD. Expression, purification and structural characterization of the type 1-specific ATP binding site of IP3 receptor (IP3R1-ATPA). Process Biochem 2015. [DOI: 10.1016/j.procbio.2015.06.010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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45
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Yarotskyy V, Dirksen RT. Monovalent cationic channel activity in the inner membrane of nuclei from skeletal muscle fibers. Biophys J 2015; 107:2027-36. [PMID: 25418088 DOI: 10.1016/j.bpj.2014.09.030] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2014] [Revised: 09/24/2014] [Accepted: 09/30/2014] [Indexed: 12/28/2022] Open
Abstract
Nuclear ion channels remain among the least studied and biophysically characterized channels. Although considerable progress has been made in characterizing calcium release channels in the nuclear membrane, very little is known regarding the properties of nuclear monovalent cationic channels. Here, we describe a method to isolate nuclei from adult skeletal muscle fibers that are suitable for electrophysiological experiments. Using this approach, we show for the first time, to our knowledge, that a nuclear monovalent cationic channel (NMCC) is prominently expressed in the inner membrane of nuclei isolated from flexor digitorum brevis skeletal muscle fibers of adult mice. In isotonic 140 mM KCl, the skeletal muscle NMCC exhibits a unitary conductance of ?160 pS and high, voltage-independent open probability. Based on single-channel reversal potential measurements, NMCCs are slightly more permeable to potassium ions over sodium (PK/PNa = 2.68 ± 0.21) and cesium (PK/PCs = 1.39 ± 0.03) ions. In addition, NMCCs do not permeate divalent cations, are inhibited by calcium ions, and demonstrate weak rectification in asymmetric Ca(2+)-containing solutions. Together, these studies characterize a voltage-independent NMCC in skeletal muscle, the properties of which are ideally suited to serve as a countercurrent mechanism during calcium release from the nuclear envelope.
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Affiliation(s)
- Viktor Yarotskyy
- Department of Pharmacology and Physiology, University of Rochester Medical Center, Rochester, New York.
| | - Robert T Dirksen
- Department of Pharmacology and Physiology, University of Rochester Medical Center, Rochester, New York
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46
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Tohmonda T, Yoda M, Iwawaki T, Matsumoto M, Nakamura M, Mikoshiba K, Toyama Y, Horiuchi K. IRE1α/XBP1-mediated branch of the unfolded protein response regulates osteoclastogenesis. J Clin Invest 2015; 125:3269-79. [PMID: 26193638 DOI: 10.1172/jci76765] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2014] [Accepted: 06/09/2015] [Indexed: 01/16/2023] Open
Abstract
The unfolded protein response (UPR) is a cellular adaptive mechanism that is activated in response to the accumulation of unfolded proteins in the endoplasmic reticulum. The inositol-requiring protein-1α/X-box-binding protein-mediated (IRE1α/XBP1-mediated) branch of the UPR is highly conserved and has also been shown to regulate various cell-fate decisions. Herein, we have demonstrated a crucial role for the IREα/XBP1-mediated arm of the UPR in osteoclast differentiation. Using murine models, we found that the conditional abrogation of IRE1α in bone marrow cells increases bone mass as the result of defective osteoclastic bone resorption. In osteoclast precursors, IRE1α was transiently activated during osteoclastogenesis, and suppression of the IRE1α/XBP1 pathway in these cells substantially inhibited the formation of multinucleated osteoclasts in vitro. We determined that XBP1 directly binds the promoter and induces transcription of the gene encoding the master regulator of osteoclastogenesis nuclear factor of activated T cells cytoplasmic 1 (NFATc1). Moreover, activation of IRE1α was partially dependent on Ca2+ oscillation mediated by inositol 1,4,5-trisphosphate receptors 2 and 3 (ITPR2 and ITPR3) in the endoplasmic reticulum, as pharmacological inhibition or deletion of these receptors markedly decreased Xbp1 mRNA processing. The present study thus reveals an intracellular pathway that integrates the UPR and osteoclast differentiation through activation of the IRE1α/XBP1 pathway.
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Leblanc N, Forrest AS, Ayon RJ, Wiwchar M, Angermann JE, Pritchard HAT, Singer CA, Valencik ML, Britton F, Greenwood IA. Molecular and functional significance of Ca(2+)-activated Cl(-) channels in pulmonary arterial smooth muscle. Pulm Circ 2015; 5:244-68. [PMID: 26064450 DOI: 10.1086/680189] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/01/2014] [Accepted: 07/22/2014] [Indexed: 12/31/2022] Open
Abstract
Increased peripheral resistance of small distal pulmonary arteries is a hallmark signature of pulmonary hypertension (PH) and is believed to be the consequence of enhanced vasoconstriction to agonists, thickening of the arterial wall due to remodeling, and increased thrombosis. The elevation in arterial tone in PH is attributable, at least in part, to smooth muscle cells of PH patients being more depolarized and displaying higher intracellular Ca(2+) levels than cells from normal subjects. It is now clear that downregulation of voltage-dependent K(+) channels (e.g., Kv1.5) and increased expression and activity of voltage-dependent (Cav1.2) and voltage-independent (e.g., canonical and vanilloid transient receptor potential [TRPC and TRPV]) Ca(2+) channels play an important role in the functional remodeling of pulmonary arteries in PH. This review focuses on an anion-permeable channel that is now considered a novel excitatory mechanism in the systemic and pulmonary circulations. It is permeable to Cl(-) and is activated by a rise in intracellular Ca(2+) concentration (Ca(2+)-activated Cl(-) channel, or CaCC). The first section outlines the biophysical and pharmacological properties of the channel and ends with a description of the molecular candidate genes postulated to encode for CaCCs, with particular emphasis on the bestrophin and the newly discovered TMEM16 and anoctamin families of genes. The second section provides a review of the various sources of Ca(2+) activating CaCCs, which include stimulation by mobilization from intracellular Ca(2+) stores and Ca(2+) entry through voltage-dependent and voltage-independent Ca(2+) channels. The third and final section summarizes recent findings that suggest a potentially important role for CaCCs and the gene TMEM16A in PH.
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Affiliation(s)
- Normand Leblanc
- Department of Pharmacology, University of Nevada School of Medicine, Reno, Nevada, USA
| | - Abigail S Forrest
- Department of Pharmacology, University of Nevada School of Medicine, Reno, Nevada, USA
| | - Ramon J Ayon
- Department of Medicine, University of Illinois, Chicago, Illinois, USA
| | - Michael Wiwchar
- Department of Pharmacology, University of Nevada School of Medicine, Reno, Nevada, USA
| | - Jeff E Angermann
- School of Community Health Sciences, University of Nevada, Reno, Nevada, USA
| | - Harry A T Pritchard
- Vascular Biology Research Centre, Institute of Cardiovascular and Cell Sciences, St. George's University of London, London, United Kingdom
| | - Cherie A Singer
- Department of Pharmacology, University of Nevada School of Medicine, Reno, Nevada, USA
| | - Maria L Valencik
- Department of Biochemistry and Molecular Biology, University of Nevada School of Medicine, Reno, Nevada, USA
| | - Fiona Britton
- Department of Physiology, School of Medical Sciences, University of New South Wales, Sydney, Australia
| | - Iain A Greenwood
- Vascular Biology Research Centre, Institute of Cardiovascular and Cell Sciences, St. George's University of London, London, United Kingdom
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48
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Penny CJ, Kilpatrick BS, Eden ER, Patel S. Coupling acidic organelles with the ER through Ca²⁺ microdomains at membrane contact sites. Cell Calcium 2015; 58:387-96. [PMID: 25866010 DOI: 10.1016/j.ceca.2015.03.006] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2014] [Revised: 03/13/2015] [Accepted: 03/14/2015] [Indexed: 10/23/2022]
Abstract
Acidic organelles such as lysosomes serve as non-canonical Ca(2+) stores. The Ca(2+) mobilising messenger NAADP is thought to trigger local Ca(2+) release from such stores. These events are then amplified by Ca(2+) channels on canonical ER Ca(2+) stores to generate physiologically relevant global Ca(2+) signals. Coupling likely occurs at microdomains formed at membrane contact sites between acidic organelles and the ER. Molecular analyses and computational modelling suggest heterogeneity in the composition of these contacts and predicted Ca(2+) microdomain behaviour. Conversely, acidic organelles might also locally amplify and temper ER-evoked Ca(2+) signals. Ca(2+) microdomains between distinct Ca(2+) stores are thus likely to be integral to the genesis of complex Ca(2+) signals.
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Affiliation(s)
- Christopher J Penny
- Department of Cell and Developmental Biology, University College London, London WC1E 6BT, UK
| | - Bethan S Kilpatrick
- Department of Cell and Developmental Biology, University College London, London WC1E 6BT, UK
| | - Emily R Eden
- Department of Cell Biology, Institute of Ophthalmology, University College London, London EC1V 9EL, UK
| | - Sandip Patel
- Department of Cell and Developmental Biology, University College London, London WC1E 6BT, UK.
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49
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Hedgepeth SC, Garcia MI, Wagner LE, Rodriguez AM, Chintapalli SV, Snyder RR, Hankins GDV, Henderson BR, Brodie KM, Yule DI, van Rossum DB, Boehning D. The BRCA1 tumor suppressor binds to inositol 1,4,5-trisphosphate receptors to stimulate apoptotic calcium release. J Biol Chem 2015; 290:7304-13. [PMID: 25645916 DOI: 10.1074/jbc.m114.611186] [Citation(s) in RCA: 56] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
The inositol 1,4,5-trisphosphate receptor (IP3R) is a ubiquitously expressed endoplasmic reticulum (ER)-resident calcium channel. Calcium release mediated by IP3Rs influences many signaling pathways, including those regulating apoptosis. IP3R activity is regulated by protein-protein interactions, including binding to proto-oncogenes and tumor suppressors to regulate cell death. Here we show that the IP3R binds to the tumor suppressor BRCA1. BRCA1 binding directly sensitizes the IP3R to its ligand, IP3. BRCA1 is recruited to the ER during apoptosis in an IP3R-dependent manner, and, in addition, a pool of BRCA1 protein is constitutively associated with the ER under non-apoptotic conditions. This is likely mediated by a novel lipid binding activity of the first BRCA1 C terminus domain of BRCA1. These findings provide a mechanistic explanation by which BRCA1 can act as a proapoptotic protein.
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Affiliation(s)
- Serena C Hedgepeth
- From the Department of Biochemistry and Molecular Biology, University of Texas Health Science Center at Houston, Houston, Texas 77030, the Cell Biology Graduate Program and
| | - M Iveth Garcia
- From the Department of Biochemistry and Molecular Biology, University of Texas Health Science Center at Houston, Houston, Texas 77030, the Cell Biology Graduate Program and
| | - Larry E Wagner
- the Department of Pharmacology and Physiology, University of Rochester Medical Center, Rochester, New York 14642
| | - Ana M Rodriguez
- the Department of Obstetrics and Gynecology, University of Texas Medical Branch, Galveston, Texas 77555
| | - Sree V Chintapalli
- the Department of Biology, Penn State University, University Park, Pennsylvania, 16802, and
| | - Russell R Snyder
- the Department of Obstetrics and Gynecology, University of Texas Medical Branch, Galveston, Texas 77555
| | - Gary D V Hankins
- the Department of Obstetrics and Gynecology, University of Texas Medical Branch, Galveston, Texas 77555
| | - Beric R Henderson
- the Centre for Cancer Research, Westmead Millennium Institute at Westmead Hospital, The University of Sydney, Westmead, New South Wales 2145, Australia
| | - Kirsty M Brodie
- the Centre for Cancer Research, Westmead Millennium Institute at Westmead Hospital, The University of Sydney, Westmead, New South Wales 2145, Australia
| | - David I Yule
- the Department of Pharmacology and Physiology, University of Rochester Medical Center, Rochester, New York 14642
| | - Damian B van Rossum
- the Department of Biology, Penn State University, University Park, Pennsylvania, 16802, and
| | - Darren Boehning
- From the Department of Biochemistry and Molecular Biology, University of Texas Health Science Center at Houston, Houston, Texas 77030,
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50
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Mak DOD, Foskett JK. Inositol 1,4,5-trisphosphate receptors in the endoplasmic reticulum: A single-channel point of view. Cell Calcium 2014; 58:67-78. [PMID: 25555684 DOI: 10.1016/j.ceca.2014.12.008] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2014] [Revised: 12/09/2014] [Accepted: 12/10/2014] [Indexed: 10/24/2022]
Abstract
As an intracellular Ca(2+) release channel at the endoplasmic reticulum membrane, the ubiquitous inositol 1,4,5-trisphosphate (InsP3) receptor (InsP3R) plays a crucial role in the generation, propagation and regulation of intracellular Ca(2+) signals that regulate numerous physiological and pathophysiological processes. This review provides a concise account of the fundamental single-channel properties of the InsP3R channel: its conductance properties and its regulation by InsP3 and Ca(2+), its physiological ligands, studied using nuclear patch clamp electrophysiology.
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Affiliation(s)
- Don-On Daniel Mak
- Department of Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, United States.
| | - J Kevin Foskett
- Department of Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, United States; Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, United States
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