1
|
Cauwelier C, de Ridder I, Bultynck G. Recent advances in canonical versus non-canonical Ca 2+-signaling-related anti-apoptotic Bcl-2 functions and prospects for cancer treatment. BIOCHIMICA ET BIOPHYSICA ACTA. MOLECULAR CELL RESEARCH 2024; 1871:119713. [PMID: 38521468 DOI: 10.1016/j.bbamcr.2024.119713] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/03/2023] [Revised: 01/11/2024] [Accepted: 03/20/2024] [Indexed: 03/25/2024]
Abstract
Cell fate is tightly controlled by a continuous balance between cell survival and cell death inducing mechanisms. B-cell lymphoma 2 (Bcl-2)-family members, composed of effectors and regulators, not only control apoptosis at the level of the mitochondria but also by impacting the intracellular Ca2+ homeostasis and dynamics. On the one hand, anti-apoptotic protein Bcl-2, prevents mitochondrial outer membrane permeabilization (MOMP) by scaffolding and neutralizing proapoptotic Bcl-2-family members via its hydrophobic cleft (region composed of BH-domain 1-3). On the other hand, Bcl-2 suppress pro-apoptotic Ca2+ signals by binding and inhibiting IP3 receptors via its BH4 domain, which is structurally exiled from the hydrophobic cleft by a flexible loop region (FLR). As such, Bcl-2 prevents excessive Ca2+ transfer from ER to mitochondria. Whereas regulation of both pathways requires different functional regions of Bcl-2, both seem to be connected in cancers that overexpress Bcl-2 in a life-promoting dependent manner. Here we discuss the anti-apoptotic canonical and non-canonical role, via calcium signaling, of Bcl-2 in health and cancer and evolving from this the proposed anti-cancer therapies with their shortcomings. We also argue how some cancers, with the major focus on diffuse large B-cell lymphoma (DLBCL) are difficult to treat, although theoretically prime marked for Bcl-2-targeting therapeutics. Further work is needed to understand the non-canonical functions of Bcl-2 also at organelles beyond the mitochondria, the interaction partners outside the Bcl-2 family as well as their ability to target or exploit these functions as therapeutic strategies in diseases.
Collapse
Affiliation(s)
- Claire Cauwelier
- KU Leuven, Lab. Molecular & Cellular Signaling, Dep. Cellular & Molecular Medicine, Campus Gasthuisberg O/N-I bus 802, Herestraat 49, BE-3000 Leuven, Belgium
| | - Ian de Ridder
- KU Leuven, Lab. Molecular & Cellular Signaling, Dep. Cellular & Molecular Medicine, Campus Gasthuisberg O/N-I bus 802, Herestraat 49, BE-3000 Leuven, Belgium
| | - Geert Bultynck
- KU Leuven, Lab. Molecular & Cellular Signaling, Dep. Cellular & Molecular Medicine, Campus Gasthuisberg O/N-I bus 802, Herestraat 49, BE-3000 Leuven, Belgium.
| |
Collapse
|
2
|
Ismatullah H, Jabeen I, Kiani YS. Structural and functional insight into a new emerging target IP 3R in cancer. J Biomol Struct Dyn 2024; 42:2170-2196. [PMID: 37070253 DOI: 10.1080/07391102.2023.2201332] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2023] [Accepted: 04/05/2023] [Indexed: 04/19/2023]
Abstract
Calcium signaling has been identified as an important phenomenon in a plethora of cellular processes. Inositol 1,4,5-trisphosphate receptors (IP3Rs) are ER-residing intracellular calcium (Ca2+) release channels responsible for cell bioenergetics by transferring calcium from the ER to the mitochondria. The recent availability of full-length IP3R channel structure has enabled the researchers to design the IP3 competitive ligands and reveal the channel gating mechanism by elucidating the conformational changes induced by ligands. However, limited knowledge is available for IP3R antagonists and the exact mechanism of action of these antagonists within a tumorigenic environment of a cell. Here in this review a summarized information about the role of IP3R in cell proliferation and apoptosis has been discussed. Moreover, structure and gating mechanism of IP3R in the presence of antagonists have been provided in this review. Additionally, compelling information about ligand-based studies (both agonists and antagonists) has been discussed. The shortcomings of these studies and the challenges toward the design of potent IP3R modulators have also been provided in this review. However, the conformational changes induced by antagonists for channel gating mechanism still display some major drawbacks that need to be addressed. However, the design, synthesis and availability of isoform-specific antagonists is a rather challenging one due to intra-structural similarity within the binding domain of each isoform. HighlightsThe intricate complexity of IP3R's in cellular processes declares them an important target whereby, the recently solved structure depicts the receptor's potential involvement in a complex network of processes spanning from cell proliferation to cell death.Pharmacological inhibition of IP3R attenuates the proliferation or invasiveness of cancers, thus inducing necrotic cell death.Despite significant advancements, there is a tremendous need to design new potential hits to target IP3R, based upon 3D structural features and pharmacophoric patterns.Communicated by Ramaswamy H. Sarma.
Collapse
Affiliation(s)
- Humaira Ismatullah
- Department of Sciences, School of Interdisciplinary Engineering and Sciences (SINES), National University of Sciences and Technology (NUST), Islamabad, Pakistan
| | - Ishrat Jabeen
- Department of Sciences, School of Interdisciplinary Engineering and Sciences (SINES), National University of Sciences and Technology (NUST), Islamabad, Pakistan
| | - Yusra Sajid Kiani
- Department of Sciences, School of Interdisciplinary Engineering and Sciences (SINES), National University of Sciences and Technology (NUST), Islamabad, Pakistan
| |
Collapse
|
3
|
Woll KA, Van Petegem F. Calcium Release Channels: Structure and Function of IP3 Receptors and Ryanodine Receptors. Physiol Rev 2021; 102:209-268. [PMID: 34280054 DOI: 10.1152/physrev.00033.2020] [Citation(s) in RCA: 79] [Impact Index Per Article: 26.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Ca2+-release channels are giant membrane proteins that control the release of Ca2+ from the endoplasmic and sarcoplasmic reticulum. The two members, ryanodine receptors (RyRs) and inositol-1,4,5-trisphosphate Receptors (IP3Rs), are evolutionarily related and are both activated by cytosolic Ca2+. They share a common architecture, but RyRs have evolved additional modules in the cytosolic region. Their massive size allows for the regulation by tens of proteins and small molecules, which can affect the opening and closing of the channels. In addition to Ca2+, other major triggers include IP3 for the IP3Rs, and depolarization of the plasma membrane for a particular RyR subtype. Their size has made them popular targets for study via electron microscopic methods, with current structures culminating near 3Å. The available structures have provided many new mechanistic insights int the binding of auxiliary proteins and small molecules, how these can regulate channel opening, and the mechanisms of disease-associated mutations. They also help scrutinize previously proposed binding sites, as some of these are now incompatible with the structures. Many questions remain around the structural effects of post-translational modifications, additional binding partners, and the higher-order complexes these channels can make in situ. This review summarizes our current knowledge about the structures of Ca2+-release channels and how this informs on their function.
Collapse
Affiliation(s)
- Kellie A Woll
- Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, BC, Canada
| | - Filip Van Petegem
- Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, BC, Canada
| |
Collapse
|
4
|
New Insights in the IP 3 Receptor and Its Regulation. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2020; 1131:243-270. [PMID: 31646513 DOI: 10.1007/978-3-030-12457-1_10] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The inositol 1,4,5-trisphosphate (IP3) receptor (IP3R) is a Ca2+-release channel mainly located in the endoplasmic reticulum (ER). Three IP3R isoforms are responsible for the generation of intracellular Ca2+ signals that may spread across the entire cell or occur locally in so-called microdomains. Because of their ubiquitous expression, these channels are involved in the regulation of a plethora of cellular processes, including cell survival and cell death. To exert their proper function a fine regulation of their activity is of paramount importance. In this review, we will highlight the recent advances in the structural analysis of the IP3R and try to link these data with the newest information concerning IP3R activation and regulation. A special focus of this review will be directed towards the regulation of the IP3R by protein-protein interaction. Especially the protein family formed by calmodulin and related Ca2+-binding proteins and the pro- and anti-apoptotic/autophagic Bcl-2-family members will be highlighted. Finally, recently identified and novel IP3R regulatory proteins will be discussed. A number of these interactions are involved in cancer development, illustrating the potential importance of modulating IP3R-mediated Ca2+ signaling in cancer treatment.
Collapse
|
5
|
Abstract
In the body, extracellular stimuli produce inositol 1,4,5-trisphosphate (IP3), an intracellular chemical signal that binds to the IP3 receptor (IP3R) to release calcium ions (Ca2+) from the endoplasmic reticulum. In the past 40 years, the wide-ranging functions mediated by IP3R and its genetic defects causing a variety of disorders have been unveiled. Recent cryo-electron microscopy and X-ray crystallography have resolved IP3R structures and begun to integrate with concurrent functional studies, which can explicate IP3-dependent opening of Ca2+-conducting gates placed ∼90 Å away from IP3-binding sites and its regulation by Ca2+. This review highlights recent research progress on the IP3R structure and function. We also propose how protein plasticity within IP3R, which involves allosteric gating and assembly transformations accompanied by rapid and chronic structural changes, would enable it to regulate diverse functions at cellular microdomains in pathophysiological states.
Collapse
Affiliation(s)
- Kozo Hamada
- Laboratory of Cell Calcium Signaling, Shanghai Institute for Advanced Immunochemical Studies (SIAIS), ShanghaiTech University, Shanghai, 201210, China; ,
| | - Katsuhiko Mikoshiba
- Laboratory of Cell Calcium Signaling, Shanghai Institute for Advanced Immunochemical Studies (SIAIS), ShanghaiTech University, Shanghai, 201210, China; ,
| |
Collapse
|
6
|
Paknejad N, Hite RK. Structural basis for the regulation of inositol trisphosphate receptors by Ca 2+ and IP 3. Nat Struct Mol Biol 2018; 25:660-668. [PMID: 30013099 PMCID: PMC6082148 DOI: 10.1038/s41594-018-0089-6] [Citation(s) in RCA: 72] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2018] [Accepted: 06/18/2018] [Indexed: 11/17/2022]
Abstract
Inositol trisphosphate receptors (IP3R) are ubiquitous Ca2+-permeable channels that mediate release of Ca2+ from the endoplasmic reticulum to regulate numerous processes including cell division, cell death, differentiation and fertilization. IP3R is activated by both IP3 and its permeant ion Ca2+. At high concentrations, however, Ca2+ inhibits activity ensuring precise spatiotemporal control over intracellular Ca2+. Despite extensive characterization of IP3R, the mechanisms by which these molecules control channel gating have remained elusive. Here, we present structures of full-length human type 3 IP3R in ligand-bound and ligand-free states. Multiple IP3-bound structures demonstrate that the large cytoplasmic domain provides a platform for propagation of long-range conformational changes to the ion conduction gate. Structures in the presence of Ca2+ reveal two Ca2+ binding sites that induce the disruption of numerous interactions between subunits, thereby inhibiting IP3R. These structures thus begin to provide a mechanistic basis for understanding the regulation of IP3R.
Collapse
Affiliation(s)
- Navid Paknejad
- Structural Biology Program, Memorial Sloan Kettering Cancer Center, New York, NY, USA.,Physiology, Biophysics and Systems Biology Graduate Program, Weill Cornell Medical College, New York, NY, USA
| | - Richard K Hite
- Structural Biology Program, Memorial Sloan Kettering Cancer Center, New York, NY, USA.
| |
Collapse
|
7
|
Egorova PA, Bezprozvanny IB. Inositol 1,4,5-trisphosphate receptors and neurodegenerative disorders. FEBS J 2018; 285:3547-3565. [PMID: 29253316 DOI: 10.1111/febs.14366] [Citation(s) in RCA: 52] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2017] [Revised: 11/27/2017] [Accepted: 12/12/2017] [Indexed: 12/15/2022]
Abstract
The inositol 1,4,5-trisphosphate receptor (IP3 R) is an intracellular ion channel that mediates the release of calcium ions from the endoplasmic reticulum. It plays a role in basic biological functions, such as cell division, differentiation, fertilization and cell death, and is involved in developmental processes including learning, memory and behavior. Deregulation of neuronal calcium signaling results in disturbance of cell homeostasis, synaptic loss and dysfunction, eventually leading to cell death. Three IP3 R subtypes have been identified in mammalian cells and the predominant isoform in neurons is IP3 R type 1. Dysfunction of IP3 R type 1 may play a role in the pathogenesis of certain neurodegenerative diseases as enhanced activity of the IP3 R was observed in models of Huntington's disease, spinocerebellar ataxias and Alzheimer's disease. These results suggest that IP3 R-mediated signaling is a potential target for treatment of these disorders. In this review we discuss the structure, functions and regulation of the IP3 R in healthy neurons and in conditions of neurodegeneration.
Collapse
Affiliation(s)
- Polina A Egorova
- Laboratory of Molecular Neurodegeneration, Peter the Great St. Petersburg Polytechnic University, St Petersburg, Russia
| | - Ilya B Bezprozvanny
- Laboratory of Molecular Neurodegeneration, Peter the Great St. Petersburg Polytechnic University, St Petersburg, Russia.,Department of Physiology, University of Texas Southwestern Medical Center, Dallas, TX, USA
| |
Collapse
|
8
|
Baker MR, Fan G, Serysheva II. Structure of IP 3R channel: high-resolution insights from cryo-EM. Curr Opin Struct Biol 2017; 46:38-47. [PMID: 28618351 PMCID: PMC5683905 DOI: 10.1016/j.sbi.2017.05.014] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2016] [Revised: 05/08/2017] [Accepted: 05/25/2017] [Indexed: 01/19/2023]
Abstract
Inositol 1,4,5-trisphosphate receptors (IP3Rs) are ubiquitously expressed intracellular Ca2+ channels and the major mediators of cellular Ca2+ signals generated by the release of Ca2+ ions from intracellular stores in response to a variety of extracellular stimuli. Despite established physiological significance and proven involvements of IP3R channels in many human diseases, detailed structural basis for signal detection by these ion channels and their gating remain obscure. Recently, single particle electron cryomicroscopy (cryo-EM) has yielded a long-awaited near-atomic resolution structure of the entire full-length type 1 IP3R. This structure provided exciting mechanistic insights into the molecular assembly of IP3R, revealing the pronounced structural conservation of Ca2+ release channels and raising many fundamental and controversial questions on their activation and gating. Here we summarize the major technological advances that propelled our cryo-EM analysis of IP3R to near-atomic resolution and discuss what the future holds for structural biology of Ca2+ release channels.
Collapse
Affiliation(s)
- Mariah R Baker
- Structural Biology Imaging Center, Department of Biochemistry and Molecular Biology, McGovern Medical School at The University of Texas Health Science Center at Houston, 6431 Fannin Street, Houston, TX 77030, USA
| | - Guizhen Fan
- Structural Biology Imaging Center, Department of Biochemistry and Molecular Biology, McGovern Medical School at The University of Texas Health Science Center at Houston, 6431 Fannin Street, Houston, TX 77030, USA
| | - Irina I Serysheva
- Structural Biology Imaging Center, Department of Biochemistry and Molecular Biology, McGovern Medical School at The University of Texas Health Science Center at Houston, 6431 Fannin Street, Houston, TX 77030, USA.
| |
Collapse
|
9
|
IP 3 receptor signaling and endothelial barrier function. Cell Mol Life Sci 2017; 74:4189-4207. [PMID: 28803370 DOI: 10.1007/s00018-017-2624-8] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2017] [Revised: 07/18/2017] [Accepted: 08/08/2017] [Indexed: 12/14/2022]
Abstract
The endothelium, a monolayer of endothelial cells lining vessel walls, maintains tissue-fluid homeostasis by restricting the passage of the plasma proteins and blood cells into the interstitium. The ion Ca2+, a ubiquitous secondary messenger, initiates signal transduction events in endothelial cells that is critical to control of vascular tone and endothelial permeability. The ion Ca2+ is stored inside the intracellular organelles and released into the cytosol in response to environmental cues. The inositol 1,4,5-trisphosphate (IP3) messenger facilitates Ca2+ release through IP3 receptors which are Ca2+-selective intracellular channels located within the membrane of the endoplasmic reticulum. Binding of IP3 to the IP3Rs initiates assembly of IP3R clusters, a key event responsible for amplification of Ca2+ signals in endothelial cells. This review discusses emerging concepts related to architecture and dynamics of IP3R clusters, and their specific role in propagation of Ca2+ signals in endothelial cells.
Collapse
|
10
|
IP 3-mediated gating mechanism of the IP 3 receptor revealed by mutagenesis and X-ray crystallography. Proc Natl Acad Sci U S A 2017; 114:4661-4666. [PMID: 28416699 DOI: 10.1073/pnas.1701420114] [Citation(s) in RCA: 59] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The inositol 1,4,5-trisphosphate (IP3) receptor (IP3R) is an IP3-gated ion channel that releases calcium ions (Ca2+) from the endoplasmic reticulum. The IP3-binding sites in the large cytosolic domain are distant from the Ca2+ conducting pore, and the allosteric mechanism of how IP3 opens the Ca2+ channel remains elusive. Here, we identify a long-range gating mechanism uncovered by channel mutagenesis and X-ray crystallography of the large cytosolic domain of mouse type 1 IP3R in the absence and presence of IP3 Analyses of two distinct space group crystals uncovered an IP3-dependent global translocation of the curvature α-helical domain interfacing with the cytosolic and channel domains. Mutagenesis of the IP3R channel revealed an essential role of a leaflet structure in the α-helical domain. These results suggest that the curvature α-helical domain relays IP3-controlled global conformational dynamics to the channel through the leaflet, conferring long-range allosteric coupling from IP3 binding to the Ca2+ channel.
Collapse
|
11
|
Raffaello A, Mammucari C, Gherardi G, Rizzuto R. Calcium at the Center of Cell Signaling: Interplay between Endoplasmic Reticulum, Mitochondria, and Lysosomes. Trends Biochem Sci 2016; 41:1035-1049. [PMID: 27692849 DOI: 10.1016/j.tibs.2016.09.001] [Citation(s) in RCA: 344] [Impact Index Per Article: 43.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2016] [Revised: 08/31/2016] [Accepted: 09/07/2016] [Indexed: 12/29/2022]
Abstract
In recent years, rapid discoveries have been made relating to Ca2+ handling at specific organelles that have important implications for whole-cell Ca2+ homeostasis. In particular, the structures of the endoplasmic reticulum (ER) Ca2+ channels revealed by electron cryomicroscopy (cryo-EM), continuous updates on the structure, regulation, and role of the mitochondrial calcium uniporter (MCU) complex, and the analysis of lysosomal Ca2+ signaling are milestones on the route towards a deeper comprehension of the complexity of global Ca2+ signaling. In this review we summarize recent discoveries on the regulation of interorganellar Ca2+ homeostasis and its role in pathophysiology.
Collapse
Affiliation(s)
- Anna Raffaello
- Department of Biomedical Sciences, University of Padua, 35131 Padua, Italy.
| | - Cristina Mammucari
- Department of Biomedical Sciences, University of Padua, 35131 Padua, Italy.
| | - Gaia Gherardi
- Department of Biomedical Sciences, University of Padua, 35131 Padua, Italy
| | - Rosario Rizzuto
- Department of Biomedical Sciences, University of Padua, 35131 Padua, Italy; Neuroscience Institute, National Research Council, 35131 Padua, Italy.
| |
Collapse
|
12
|
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.
Collapse
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.
| |
Collapse
|
13
|
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.
Collapse
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
| |
Collapse
|
14
|
Wang L, Alzayady KJ, Yule DI. Proteolytic fragmentation of inositol 1,4,5-trisphosphate receptors: a novel mechanism regulating channel activity? J Physiol 2015; 594:2867-76. [PMID: 26486785 DOI: 10.1113/jp271140] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2015] [Accepted: 09/30/2015] [Indexed: 12/15/2022] Open
Abstract
Inositol 1,4,5-trisphosphate receptors (IP3 Rs) are a family of ubiquitously expressed intracellular Ca(2+) release channels. Regulation of channel activity by Ca(2+) , nucleotides, phosphorylation, protein binding partners and other cellular factors is thought to play a major role in defining the specific spatiotemporal characteristics of intracellular Ca(2+) signals. These properties are, in turn, believed pivotal for the selective and specific physiological activation of Ca(2+) -dependent effectors. IP3 Rs are also substrates for the intracellular cysteine proteases, calpain and caspase. Cleavage of the IP3 R has been proposed to play a role in apoptotic cell death by uncoupling regions important for IP3 binding from the channel domain, leaving an unregulated leaky Ca(2+) pore. Contrary to this hypothesis, we demonstrate following proteolysis that N- and C-termini of IP3 R1 remain associated, presumably through non-covalent interactions. Further, we show that complementary fragments of IP3 R1 assemble into tetrameric structures and retain their ability to be regulated robustly by IP3 . While peptide continuity is clearly not necessary for IP3 -gating of the channel, we propose that cleavage of the IP3 R peptide chain may alter other important regulatory events to modulate channel activity. In this scenario, stimulation of the cleaved IP3 R may support distinct spatiotemporal Ca(2+) signals and activation of specific effectors. Notably, in many adaptive physiological events, the non-apoptotic activities of caspase and calpain are demonstrated to be important, but the substrates of the proteases are poorly defined. We speculate that proteolytic fragmentation may represent a novel form of IP3 R regulation, which plays a role in varied adaptive physiological processes.
Collapse
Affiliation(s)
- Liwei Wang
- Department of Pharmacology and Physiology, University of Rochester, 601 Elmwood Avenue, Rochester, NY, 14642, USA
| | - Kamil J Alzayady
- Department of Pharmacology and Physiology, University of Rochester, 601 Elmwood Avenue, Rochester, NY, 14642, USA
| | - David I Yule
- Department of Pharmacology and Physiology, University of Rochester, 601 Elmwood Avenue, Rochester, NY, 14642, USA
| |
Collapse
|
15
|
Fan G, Baker ML, Wang Z, Baker MR, Sinyagovskiy PA, Chiu W, Ludtke SJ, Serysheva II. Gating machinery of InsP3R channels revealed by electron cryomicroscopy. Nature 2015; 527:336-41. [PMID: 26458101 DOI: 10.1038/nature15249] [Citation(s) in RCA: 168] [Impact Index Per Article: 18.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2015] [Accepted: 07/24/2015] [Indexed: 12/12/2022]
Abstract
Inositol-1,4,5-trisphosphate receptors (InsP3Rs) are ubiquitous ion channels responsible for cytosolic Ca(2+) signalling and essential for a broad array of cellular processes ranging from contraction to secretion, and from proliferation to cell death. Despite decades of research on InsP3Rs, a mechanistic understanding of their structure-function relationship is lacking. Here we present the first, to our knowledge, near-atomic (4.7 Å) resolution electron cryomicroscopy structure of the tetrameric mammalian type 1 InsP3R channel in its apo-state. At this resolution, we are able to trace unambiguously ∼85% of the protein backbone, allowing us to identify the structural elements involved in gating and modulation of this 1.3-megadalton channel. Although the central Ca(2+)-conduction pathway is similar to other ion channels, including the closely related ryanodine receptor, the cytosolic carboxy termini are uniquely arranged in a left-handed α-helical bundle, directly interacting with the amino-terminal domains of adjacent subunits. This configuration suggests a molecular mechanism for allosteric regulation of channel gating by intracellular signals.
Collapse
Affiliation(s)
- Guizhen Fan
- Department of Biochemistry and Molecular Biology, Structural Biology Imaging Center, The University of Texas Medical School at Houston, 6431 Fannin Street, Houston, Texas 77030, USA
| | - Matthew L Baker
- National Center for Macromolecular Imaging, Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, One Baylor Plaza, Houston, Texas 77030, USA
| | - Zhao Wang
- National Center for Macromolecular Imaging, Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, One Baylor Plaza, Houston, Texas 77030, USA
| | - Mariah R Baker
- Department of Biochemistry and Molecular Biology, Structural Biology Imaging Center, The University of Texas Medical School at Houston, 6431 Fannin Street, Houston, Texas 77030, USA
| | - Pavel A Sinyagovskiy
- Department of Biochemistry and Molecular Biology, Structural Biology Imaging Center, The University of Texas Medical School at Houston, 6431 Fannin Street, Houston, Texas 77030, USA
| | - Wah Chiu
- National Center for Macromolecular Imaging, Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, One Baylor Plaza, Houston, Texas 77030, USA
| | - Steven J Ludtke
- National Center for Macromolecular Imaging, Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, One Baylor Plaza, Houston, Texas 77030, USA
| | - Irina I Serysheva
- Department of Biochemistry and Molecular Biology, Structural Biology Imaging Center, The University of Texas Medical School at Houston, 6431 Fannin Street, Houston, Texas 77030, USA
| |
Collapse
|
16
|
Chandrasekhar R, Alzayady KJ, Yule DI. Using concatenated subunits to investigate the functional consequences of heterotetrameric inositol 1,4,5-trisphosphate receptors. Biochem Soc Trans 2015; 43:364-70. [PMID: 26009177 PMCID: PMC4677331 DOI: 10.1042/bst20140287] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Inositol 1,4,5-trisphosphate receptors (IP3Rs) are a family of ubiquitous, ER localized, tetrameric Ca2+ release channels. There are three subtypes of the IP3Rs (R1, R2, R3), encoded by three distinct genes, that share ∼60-70% sequence identity. The diversity of Ca2+ signals generated by IP3Rs is thought to be largely the result of differential tissue expression, intracellular localization and subtype-specific regulation of the three subtypes by various cellular factors, most significantly InsP3, Ca2+ and ATP. However, largely unexplored is the notion of additional signal diversity arising from the assembly of both homo and heterotetrameric InsP3Rs. In the present article, we review the biochemical and functional evidence supporting the existence of homo and heterotetrameric populations of InsP3Rs. In addition, we consider a strategy that utilizes genetically concatenated InsP3Rs to study the functional characteristics of heterotetramers with unequivocally defined composition. This approach reveals that the overall properties of IP3R are not necessarily simply a blend of the constituent monomers but that specific subtypes appear to dominate the overall characteristics of the tetramer. It is envisioned that the ability to generate tetramers with defined wild type and mutant subunits will be useful in probing fundamental questions relating to IP3R structure and function.
Collapse
MESH Headings
- Adenosine Triphosphate/chemistry
- Adenosine Triphosphate/metabolism
- Calcium Signaling/genetics
- Humans
- Inositol 1,4,5-Trisphosphate/chemistry
- Inositol 1,4,5-Trisphosphate/metabolism
- Inositol 1,4,5-Trisphosphate Receptors/chemistry
- Inositol 1,4,5-Trisphosphate Receptors/genetics
- Inositol 1,4,5-Trisphosphate Receptors/metabolism
- Protein Multimerization
- Protein Structure, Tertiary
- Structure-Activity Relationship
Collapse
|
17
|
Shah SZA, Zhao D, Khan SH, Yang L. Regulatory Mechanisms of Endoplasmic Reticulum Resident IP3 Receptors. J Mol Neurosci 2015; 56:938-948. [PMID: 25859934 DOI: 10.1007/s12031-015-0551-4] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2015] [Accepted: 03/23/2015] [Indexed: 11/25/2022]
Abstract
Dysregulated calcium signaling and accumulation of aberrant proteins causing endoplasmic reticulum stress are the early sign of intra-axonal pathological events in many neurodegenerative diseases, and apoptotic signaling is initiated when the stress goes beyond the maximum threshold level of endoplasmic reticulum. The fate of the cell to undergo apoptosis is controlled by Ca2(+) signaling and dynamics at the level of the endoplasmic reticulum. Endoplasmic reticulum resident inositol 1,4,5-trisphosphate receptors (IP3R) play a pivotal role in cell death signaling by mediating Ca2(+) flux from the endoplasmic reticulum into the cytosol and mitochondria. Hence, many prosurvival and prodeath signaling pathways and proteins affect Ca2(+) signaling by directly targeting IP3R channels, which can happen in an IP3R-isoform-dependent manner. Here, in this review, we summarize the regulatory mechanisms of inositol triphosphate receptors in calcium regulation and initiation of apoptosis during unfolded protein response.
Collapse
Affiliation(s)
- Syed Zahid Ali Shah
- State Key Laboratories for Agrobiotechnology, Key Lab of Animal Epidemiology and Zoonosis, Ministry of Agriculture, National Animal Transmissible Spongiform Encephalopathy Laboratory, College of Veterinary Medicine, China Agricultural University, Beijing, 100193, China
| | - Deming Zhao
- State Key Laboratories for Agrobiotechnology, Key Lab of Animal Epidemiology and Zoonosis, Ministry of Agriculture, National Animal Transmissible Spongiform Encephalopathy Laboratory, College of Veterinary Medicine, China Agricultural University, Beijing, 100193, China
| | - Sher Hayat Khan
- State Key Laboratories for Agrobiotechnology, Key Lab of Animal Epidemiology and Zoonosis, Ministry of Agriculture, National Animal Transmissible Spongiform Encephalopathy Laboratory, College of Veterinary Medicine, China Agricultural University, Beijing, 100193, China
| | - Lifeng Yang
- State Key Laboratories for Agrobiotechnology, Key Lab of Animal Epidemiology and Zoonosis, Ministry of Agriculture, National Animal Transmissible Spongiform Encephalopathy Laboratory, College of Veterinary Medicine, China Agricultural University, Beijing, 100193, China.
| |
Collapse
|
18
|
Seo MD, Enomoto M, Ishiyama N, Stathopulos PB, Ikura M. Structural insights into endoplasmic reticulum stored calcium regulation by inositol 1,4,5-trisphosphate and ryanodine receptors. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2014; 1853:1980-91. [PMID: 25461839 DOI: 10.1016/j.bbamcr.2014.11.023] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/11/2014] [Revised: 11/17/2014] [Accepted: 11/19/2014] [Indexed: 10/24/2022]
Abstract
The two major calcium (Ca²⁺) release channels on the sarco/endoplasmic reticulum (SR/ER) are inositol 1,4,5-trisphosphate and ryanodine receptors (IP3Rs and RyRs). They play versatile roles in essential cell signaling processes, and abnormalities of these channels are associated with a variety of diseases. Structural information on IP3Rs and RyRs determined using multiple techniques including X-ray crystallography, nuclear magnetic resonance (NMR) spectroscopy and cryo-electron microscopy (EM), has significantly advanced our understanding of the mechanisms by which these Ca²⁺ release channels function under normal and pathophysiological circumstances. In this review, structural advances on the understanding of the mechanisms of IP3R and RyR function and dysfunction are summarized. This article is part of a Special Issue entitled: 13th European Symposium on Calcium.
Collapse
Affiliation(s)
- Min-Duk Seo
- Department of Molecular Science and Technology, Ajou University, Suwon, Gyeonggi 443-749, Republic of Korea; College of Pharmacy, Ajou University, Suwon, Gyeonggi 443-749, Republic of Korea
| | - Masahiro Enomoto
- Princess Margaret Cancer Centre, University Health Network, University of Toronto, Toronto, ON M5G 1L7, Canada
| | - Noboru Ishiyama
- Princess Margaret Cancer Centre, University Health Network, University of Toronto, Toronto, ON M5G 1L7, Canada
| | - Peter B Stathopulos
- Department of Physiology and Pharmacology, Schulich School of Medicine and Dentistry, University of Western Ontario, London, ON N6A 5C1, Canada
| | - Mitsuhiko Ikura
- Princess Margaret Cancer Centre, University Health Network, University of Toronto, Toronto, ON M5G 1L7, Canada.
| |
Collapse
|
19
|
Zhang N, Fissore RA. Role of caspase-3 cleaved IP3 R1 on Ca(2+) homeostasis and developmental competence of mouse oocytes and eggs. J Cell Physiol 2014; 229:1842-54. [PMID: 24692207 DOI: 10.1002/jcp.24638] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2013] [Accepted: 03/28/2014] [Indexed: 11/12/2022]
Abstract
Apoptosis in most cell types is accompanied by altered Ca(2+) homeostasis. During apoptosis, caspase-3 mediated cleavage of the type 1 inositol 1,4,5-trisphosphate receptor (IP3 R1) generates a 95-kDa C-terminal fragment (C-IP3 R1), which represents the channel domain of the receptor. Aged mouse eggs display abnormal Ca(2+) homeostasis and express C-IP3 R1, although whether or not C-IP3 R1 expression contributes to Ca(2+) misregulation or a decrease in developmental competency is unknown. We sought to answer these questions by injecting in mouse oocytes and eggs cRNAs encoding C-IP3 R1. We found that: (1) expression of C-IP3 R1 in eggs lowered the Ca(2+) content of the endoplasmic reticulum (ER), although, as C-IP3 R1 is quickly degraded at this stage, its expression did not impair pre-implantation embryo development; (2) expression of C-IP3 R1 in eggs enhanced fragmentation associated with aging; (3) endogenous IP3 R1 is required for aging associated apoptosis, as its down-regulation prevented fragmentation, and expression of C-IP3 R1 in eggs with downregulated IP3 R1 partly restored fragmentation; (4) C-IP3 R1 expression in GV oocytes resulted in persistent levels of protein, which abolished the increase in the ER releasable Ca(2+) pool that occurs during maturation, undermined the Ca(2+) oscillatory ability of matured eggs and their activation potential. Collectively, this study supports a role for IP3 R1 and C-IP3 R1 in regulating Ca(2+) homeostasis and the ER Ca(2+) content during oocyte maturation. Nevertheless, the role of C-IP3 R1 on Ca(2+) homeostasis in aged eggs seems minor, as in MII eggs the majority of endogenous IP3 R1 remains intact and C-IP3 R1 undergoes rapid turnover.
Collapse
Affiliation(s)
- Nan Zhang
- Department of Veterinary and Animal Sciences, University of Massachusetts Amherst, Amherst, Massachusetts
| | | |
Collapse
|
20
|
Aberrant calcium signaling by transglutaminase-mediated posttranslational modification of inositol 1,4,5-trisphosphate receptors. Proc Natl Acad Sci U S A 2014; 111:E3966-75. [PMID: 25201980 DOI: 10.1073/pnas.1409730111] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
The inositol 1,4,5-trisphosphate receptor (IP3R) in the endoplasmic reticulum mediates calcium signaling that impinges on intracellular processes. IP3Rs are allosteric proteins comprising four subunits that form an ion channel activated by binding of IP3 at a distance. Defective allostery in IP3R is considered crucial to cellular dysfunction, but the specific mechanism remains unknown. Here we demonstrate that a pleiotropic enzyme transglutaminase type 2 targets the allosteric coupling domain of IP3R type 1 (IP3R1) and negatively regulates IP3R1-mediated calcium signaling and autophagy by locking the subunit configurations. The control point of this regulation is the covalent posttranslational modification of the Gln2746 residue that transglutaminase type 2 tethers to the adjacent subunit. Modification of Gln2746 and IP3R1 function was observed in Huntington disease models, suggesting a pathological role of this modification in the neurodegenerative disease. Our study reveals that cellular signaling is regulated by a new mode of posttranslational modification that chronically and enzymatically blocks allosteric changes in the ligand-gated channels that relate to disease states.
Collapse
|
21
|
Abstract
In the 30 years since IP3 (inositol 1,4,5-trisphosphate) was first shown to release Ca2+ from intracellular stores, the importance of spatially organized interactions within IP3-regulated signalling pathways has been universally recognized. Recent evidence that addresses three different levels of the structural determinants of IP3-evoked Ca2+ signalling is described in the present review. High-resolution structures of the N-terminal region of the IP3R (IP3 receptor) have established that the two essential phosphate groups of IP3 bind to opposite sides of the IP3-binding site, pulling its two domains together. This conformational change is proposed to disrupt an interaction between adjacent subunits within the tetrameric IP3R that normally holds the channel in a closed state. Similar structural changes are thought to allow gating of ryanodine receptors. cAMP increases the sensitivity of IP3Rs and thereby potentiates the Ca2+ signals evoked by receptors that stimulate IP3 formation. We speculate that both IP3 and cAMP are delivered to IP3Rs within signalling junctions, wherein the associated IP3Rs are exposed to a saturating concentration of either messenger. The concentration-dependent effects of extracellular stimuli come from recruitment of junctions rather than from a graded increase in the activity of individual junctions. IP3Rs within 'IP3 junctions' respond directly to receptors that stimulate phospholipase C, whereas extra-junctional IP3Rs are exposed to suboptimal concentrations of IP3 and open only when they are sensitized by cAMP. These results highlight the importance of selective delivery of diffusible messengers to IP3Rs. The spatial organization of IP3Rs also allows them to direct Ca2+ to specific intracellular targets that include other IP3Rs, mitochondria and Ca2+-regulated channels and enzymes. IP3Rs also interact functionally with lysosomes because Ca2+ released by IP3Rs, but not that entering cells via store-operated Ca2+ entry pathways, is selectively accumulated by lysosomes. This Ca2+ uptake shapes the Ca2+ signals evoked by IP3 and it may regulate lysosomal behaviour.
Collapse
|
22
|
Serysheva II. Toward a high-resolution structure of IP₃R channel. Cell Calcium 2014; 56:125-32. [PMID: 25159857 DOI: 10.1016/j.ceca.2014.08.002] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2014] [Revised: 08/01/2014] [Accepted: 08/02/2014] [Indexed: 12/11/2022]
Abstract
The ability of cells to maintain low levels of Ca(2+) under resting conditions and to create rapid and transient increases in Ca(2+) upon stimulation is a fundamental property of cellular Ca(2+) signaling mechanism. An increase of cytosolic Ca(2+) level in response to diverse stimuli is largely accounted for by the inositol 1,4,5-trisphosphate receptor (IP3R) present in the endoplasmic reticulum membranes of virtually all eukaryotic cells. Extensive information is currently available on the function of IP3Rs and their interaction with modulators. Very little, however, is known about their molecular architecture and therefore most critical issues surrounding gating of IP3R channels are still ambiguous, including the central question of how opening of the IP3R pore is initiated by IP3 and Ca(2+). Membrane proteins such as IP3R channels have proven to be exceptionally difficult targets for structural analysis due to their large size, their location in the membrane environment, and their dynamic nature. To date, a 3D structure of complete IP3R channel is determined by single-particle cryo-EM at intermediate resolution, and the best crystal structures of IP3R are limited to a soluble portion of the cytoplasmic region representing ∼15% of the entire channel protein. Together these efforts provide the important structural information for this class of ion channels and serve as the basis for further studies aiming at understanding of the IP3R function.
Collapse
Affiliation(s)
- Irina I Serysheva
- Department of Biochemistry and Molecular Biology, The University of Texas Medical School at Houston, 6431 Fannin Street, Houston, TX 77030, USA.
| |
Collapse
|
23
|
Feng X, Krogh KA, Wu CY, Lin YW, Tsai HC, Thayer SA, Wei LN. Receptor-interacting protein 140 attenuates endoplasmic reticulum stress in neurons and protects against cell death. Nat Commun 2014; 5:4487. [PMID: 25066731 PMCID: PMC4200015 DOI: 10.1038/ncomms5487] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2014] [Accepted: 06/23/2014] [Indexed: 12/29/2022] Open
Abstract
Inositol 1, 4, 5-trisphosphate receptor (IP3R)-mediated Ca(2+) release from the endoplasmic reticulum (ER) triggers many physiological responses in neurons, and when uncontrolled can cause ER stress that contributes to neurological disease. Here we show that the unfolded protein response (UPR) in neurons induces rapid translocation of nuclear receptor-interacting protein 140 (RIP140) to the cytoplasm. In the cytoplasm, RIP140 localizes to the ER by binding to the IP3R. The carboxyl-terminal RD4 domain of RIP140 interacts with the carboxyl-terminal gate-keeping domain of the IP3R. This molecular interaction disrupts the IP3R's 'head-tail' interaction, thereby suppressing channel opening and attenuating IP3R-mediated Ca(2+) release. This contributes to a rapid suppression of the ER stress response and provides protection from apoptosis in both hippocampal neurons in vitro and in an animal model of ER stress. Thus, RIP140 translocation to the cytoplasm is an early response to ER stress and provides protection against neuronal death.
Collapse
Affiliation(s)
- Xudong Feng
- Department of Pharmacology, University of Minnesota Medical School, Minneapolis, MN 55455, USA
| | - Kelly A. Krogh
- Department of Pharmacology, University of Minnesota Medical School, Minneapolis, MN 55455, USA
| | - Cheng-Ying Wu
- Department of Pharmacology, University of Minnesota Medical School, Minneapolis, MN 55455, USA
| | - Yi-Wei Lin
- Department of Pharmacology, University of Minnesota Medical School, Minneapolis, MN 55455, USA
| | - Hong-Chieh Tsai
- Department of Pharmacology, University of Minnesota Medical School, Minneapolis, MN 55455, USA
- Department of Neurosurgery, Chang-Gung Memorial Hospital and University, Tao-Yuan, Taiwan, R.O.C
| | - Stanley A. Thayer
- Department of Pharmacology, University of Minnesota Medical School, Minneapolis, MN 55455, USA
| | - Li-Na Wei
- Department of Pharmacology, University of Minnesota Medical School, Minneapolis, MN 55455, USA
| |
Collapse
|
24
|
Ivanova H, Vervliet T, Missiaen L, Parys JB, De Smedt H, Bultynck G. Inositol 1,4,5-trisphosphate receptor-isoform diversity in cell death and survival. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2014; 1843:2164-83. [PMID: 24642269 DOI: 10.1016/j.bbamcr.2014.03.007] [Citation(s) in RCA: 139] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 12/10/2013] [Revised: 03/06/2014] [Accepted: 03/09/2014] [Indexed: 01/22/2023]
Abstract
Cell-death and -survival decisions are critically controlled by intracellular Ca(2+) homeostasis and dynamics at the level of the endoplasmic reticulum (ER). Inositol 1,4,5-trisphosphate (IP3) receptors (IP3Rs) play a pivotal role in these processes by mediating Ca(2+) flux from the ER into the cytosol and mitochondria. Hence, it is clear that many pro-survival and pro-death signaling pathways and proteins affect Ca(2+) signaling by directly targeting IP3R channels, which can happen in an IP3R-isoform-dependent manner. In this review, we will focus on how the different IP3R isoforms (IP3R1, IP3R2 and IP3R3) control cell death and survival. First, we will present an overview of the isoform-specific regulation of IP3Rs by cellular factors like IP3, Ca(2+), Ca(2+)-binding proteins, adenosine triphosphate (ATP), thiol modification, phosphorylation and interacting proteins, and of IP3R-isoform specific expression patterns. Second, we will discuss the role of the ER as a Ca(2+) store in cell death and survival and how IP3Rs and pro-survival/pro-death proteins can modulate the basal ER Ca(2+) leak. Third, we will review the regulation of the Ca(2+)-flux properties of the IP3R isoforms by the ER-resident and by the cytoplasmic proteins involved in cell death and survival as well as by redox regulation. Hence, we aim to highlight the specific roles of the various IP3R isoforms in cell-death and -survival signaling. This article is part of a Special Issue entitled: Calcium signaling in health and disease. Guest Editors: Geert Bultynck, Jacques Haiech, Claus W. Heizmann, Joachim Krebs, and Marc Moreau.
Collapse
Affiliation(s)
- Hristina Ivanova
- KU Leuven Lab. of Molecular and Cellular Signaling, Dept. of Cellular and Molecular Medicine, Campus Gasthuisberg O&N I Box 802, Herestraat 49, BE-3000 Leuven, Belgium
| | - Tim Vervliet
- KU Leuven Lab. of Molecular and Cellular Signaling, Dept. of Cellular and Molecular Medicine, Campus Gasthuisberg O&N I Box 802, Herestraat 49, BE-3000 Leuven, Belgium
| | - Ludwig Missiaen
- KU Leuven Lab. of Molecular and Cellular Signaling, Dept. of Cellular and Molecular Medicine, Campus Gasthuisberg O&N I Box 802, Herestraat 49, BE-3000 Leuven, Belgium
| | - Jan B Parys
- KU Leuven Lab. of Molecular and Cellular Signaling, Dept. of Cellular and Molecular Medicine, Campus Gasthuisberg O&N I Box 802, Herestraat 49, BE-3000 Leuven, Belgium
| | - Humbert De Smedt
- KU Leuven Lab. of Molecular and Cellular Signaling, Dept. of Cellular and Molecular Medicine, Campus Gasthuisberg O&N I Box 802, Herestraat 49, BE-3000 Leuven, Belgium.
| | - Geert Bultynck
- KU Leuven Lab. of Molecular and Cellular Signaling, Dept. of Cellular and Molecular Medicine, Campus Gasthuisberg O&N I Box 802, Herestraat 49, BE-3000 Leuven, Belgium.
| |
Collapse
|
25
|
Alzayady KJ, Wagner LE, Chandrasekhar R, Monteagudo A, Godiska R, Tall GG, Joseph SK, Yule DI. Functional inositol 1,4,5-trisphosphate receptors assembled from concatenated homo- and heteromeric subunits. J Biol Chem 2013; 288:29772-84. [PMID: 23955339 DOI: 10.1074/jbc.m113.502203] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
Vertebrate genomes code for three subtypes of inositol 1,4,5-trisphosphate (IP3) receptors (IP3R1, -2, and -3). Individual IP3R monomers are assembled to form homo- and heterotetrameric channels that mediate Ca(2+) release from intracellular stores. IP3R subtypes are regulated differentially by IP3, Ca(2+), ATP, and various other cellular factors and events. IP3R subtypes are seldom expressed in isolation in individual cell types, and cells often express different complements of IP3R subtypes. When multiple subtypes of IP3R are co-expressed, the subunit composition of channels cannot be specifically defined. Thus, how the subunit composition of heterotetrameric IP3R channels contributes to shaping the spatio-temporal properties of IP3-mediated Ca(2+) signals has been difficult to evaluate. To address this question, we created concatenated IP3R linked by short flexible linkers. Dimeric constructs were expressed in DT40-3KO cells, an IP3R null cell line. The dimeric proteins were localized to membranes, ran as intact dimeric proteins on SDS-PAGE, and migrated as an ∼1100-kDa band on blue native gels exactly as wild type IP3R. Importantly, IP3R channels formed from concatenated dimers were fully functional as indicated by agonist-induced Ca(2+) release. Using single channel "on-nucleus" patch clamp, the channels assembled from homodimers were essentially indistinguishable from those formed by the wild type receptor. However, the activity of channels formed from concatenated IP3R1 and IP3R2 heterodimers was dominated by IP3R2 in terms of the characteristics of regulation by ATP. These studies provide the first insight into the regulation of heterotetrameric IP3R of defined composition. Importantly, the results indicate that the properties of these channels are not simply a blend of those of the constituent IP3R monomers.
Collapse
Affiliation(s)
- Kamil J Alzayady
- From the Department of Pharmacology and Physiology, University of Rochester, Rochester, New York 14642
| | | | | | | | | | | | | | | |
Collapse
|
26
|
Zhang D, Liu X, Chan JD, Marchant JS. Characterization of a flatworm inositol (1,4,5) trisphosphate receptor (IP₃R) reveals a role in reproductive physiology. Cell Calcium 2013; 53:307-14. [PMID: 23481272 PMCID: PMC3665645 DOI: 10.1016/j.ceca.2013.01.003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2012] [Revised: 01/22/2013] [Accepted: 01/29/2013] [Indexed: 11/15/2022]
Abstract
Inositol 1,4,5-trisphosphate receptors (IP₃Rs) are intracellular Ca²⁺ channels that elevate cytoplasmic Ca²⁺ in response to the second messenger IP3. Here, we describe the identification and in vivo functional characterization of the planarian IP₃R, the first intracellular Ca²⁺ channel to be defined in flatworms. A single IP₃R gene in Dugesia japonica encoded a 2666 amino acid protein (Dj.IP₃R) that shared well conserved structural features with vertebrate IP₃R counterparts. Expression of an NH₂-terminal Dj.IP₃R region (amino acid residues 223-585) recovered high affinity ³H-IP₃ binding (0.9±0.1 nM) which was abolished by a single point mutation of an arginine residue (R495L) important for IP₃ coordination. In situ hybridization revealed that Dj.IP₃R mRNA was most strongly expressed in the pharynx and optical nerve system as well as the reproductive system in sexualized planarians. Consistent with this observed tissue distribution, in vivo RNAi of Dj.IP₃R resulted in a decreased egg-laying behavior suggesting Dj.IP₃R plays an upstream role in planarian reproductive physiology.
Collapse
Affiliation(s)
- Dan Zhang
- Department of Pharmacology, University of Minnesota Medical School, MN 55455, USA
| | - Xiaolong Liu
- Department of Pharmacology, University of Minnesota Medical School, MN 55455, USA
| | - John D. Chan
- Department of Pharmacology, University of Minnesota Medical School, MN 55455, USA
| | - Jonathan S. Marchant
- Department of Pharmacology, University of Minnesota Medical School, MN 55455, USA
- The Stem Cell Institute, University of Minnesota Medical School, MN 55455, USA
| |
Collapse
|
27
|
Amador FJ, Stathopulos PB, Enomoto M, Ikura M. Ryanodine receptor calcium release channels: lessons from structure-function studies. FEBS J 2013; 280:5456-70. [PMID: 23413940 DOI: 10.1111/febs.12194] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2012] [Revised: 01/24/2013] [Accepted: 02/04/2013] [Indexed: 11/28/2022]
Abstract
Ryanodine receptors (RyRs) are the largest known ion channels. They are Ca(2+) release channels found primarily on the sarcoplasmic reticulum of myocytes. Several hundred mutations in RyRs are associated with skeletal or cardiomyocyte disease in humans. Many of these mutations can now be mapped onto the high resolution structures of individual RyR domains and on full-length tetrameric cryo-electron microscopy structures. A closely related Ca(2+) release channel, the inositol 1,4,5-trisphospate receptor (IP3 R), shows a conserved structural architecture at the N-terminus, suggesting that both channels evolved from an ancestral unicellular RyR/IP3 R. The functional insights provided by recent structural studies for both channels will aid in the development of rationale treatments for a myriad of Ca(2+)-signaled malignancies.
Collapse
Affiliation(s)
- Fernando J Amador
- Ontario Cancer Institute and Department of Medical Biophysics, University of Toronto, Canada
| | | | | | | |
Collapse
|
28
|
Alzayady KJ, Chandrasekhar R, Yule DI. Fragmented inositol 1,4,5-trisphosphate receptors retain tetrameric architecture and form functional Ca2+ release channels. J Biol Chem 2013; 288:11122-34. [PMID: 23479737 DOI: 10.1074/jbc.m113.453241] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Inositol 1,4,5-trisphosphate receptor isoforms are a family of ubiquitously expressed ligand-gated channels encoded by three individual genes. The proteins are localized to membranes of intracellular Ca(2+) stores and play pivotal roles in Ca(2+) homeostasis. Previous studies have demonstrated that IP3R1 is cleaved by the intracellular proteases calpain and caspase both in vivo and in vitro. However, the resultant cleavage products are poorly defined, and the functional consequences of these proteolytic events are not fully understood. We demonstrate that IP3R1 is cleaved during staurosporine-induced apoptosis, yielding N-terminal fragments encompassing the ligand-binding domain and the majority of the central modulatory domain together with a C-terminal fragment containing the channel domain and cytosolic tail. Notably, these fragments remain associated with the membrane after initiation of apoptotic cleavage. Furthermore, when recombinant IP3R1 fragments, corresponding to those predicted to be generated by caspase or calpain cleavage, are stably coexpressed in cells, they physically associate and form functional channels. These data provide novel insights regarding the regulation of IP3R1 during proteolysis and provide direct evidence that polypeptide continuity is not required for IP3R activation and Ca(2+) release.
Collapse
Affiliation(s)
- Kamil J Alzayady
- Department of Pharmacology and Physiology, University of Rochester, Rochester, New York 14642, USA
| | | | | |
Collapse
|
29
|
Bhanumathy C, da Fonseca PCA, Morris EP, Joseph SK. Identification of functionally critical residues in the channel domain of inositol trisphosphate receptors. J Biol Chem 2012; 287:43674-84. [PMID: 23086950 PMCID: PMC3527953 DOI: 10.1074/jbc.m112.415786] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
We have combined alanine mutagenesis and functional assays to identify amino acid residues in the channel domain that are critical for inositol 1,4,5-trisphosphate receptor (IP(3)R) channel function. The residues selected were highly conserved in all three IP(3)R isoforms and were located in the cytosolic end of the S6 pore-lining helix and proximal portion of the C-tail. Two adjacent hydrophobic amino acids (Ile-2588 and Ile-2589) at the putative cytosolic interface of the S6 helix inactivated channel function and could be candidates for the channel gate. Of five negatively charged residues mutated, none completely eliminated channel function. Of five positively charged residues mutated, only one inactivated the channel (Arg-2596). In addition to the previously identified role of a pair of cysteines in the C-tail (Cys-2610 and Cys-2613), a pair of highly conserved histidines (His-2630 and His-2635) were also essential for channel function. Expression of the H2630A and H2635A mutants (but not R2596A) produced receptors with destabilized interactions between the N-terminal fragment and the channel domain. A previously unrecognized association between the cytosolic C-tail and the TM 4,5-loop was demonstrated using GST pulldown assays. However, none of the mutations in the C-tail interfered with this interaction or altered the ability of the C-tail to assemble into dimers. Our present findings and recent information on IP(3)R structure from electron microscopy and crystallography are incorporated into a revised model of channel gating.
Collapse
MESH Headings
- Amino Acid Substitution
- Animals
- COS Cells
- Chlorocebus aethiops
- HEK293 Cells
- Humans
- Inositol 1,4,5-Trisphosphate Receptors/chemistry
- Inositol 1,4,5-Trisphosphate Receptors/genetics
- Inositol 1,4,5-Trisphosphate Receptors/metabolism
- Ion Channel Gating/physiology
- Models, Molecular
- Mutation, Missense
- Protein Multimerization/physiology
- Protein Structure, Secondary
- Protein Structure, Tertiary
- Rats
Collapse
Affiliation(s)
- Cunnigaiper Bhanumathy
- From the Department of Pathology and Cell Biology, Thomas Jefferson University, Philadelphia, Pennsylvania 19107 and
| | - Paula C. A. da Fonseca
- the Institute for Cancer Research, Chester Beatty Laboratories, London, SW3 6JB, United Kingdom
| | - Edward P. Morris
- the Institute for Cancer Research, Chester Beatty Laboratories, London, SW3 6JB, United Kingdom
| | - Suresh K. Joseph
- From the Department of Pathology and Cell Biology, Thomas Jefferson University, Philadelphia, Pennsylvania 19107 and
- To whom correspondence should be addressed: Dept. of Pathology & Cell Biology, Rm. 230A JAH, 1020 Locust St., Philadelphia, PA 19107. Tel.: 215-503-1222; E-mail:
| |
Collapse
|
30
|
Monaco G, Beckers M, Ivanova H, Missiaen L, Parys JB, De Smedt H, Bultynck G. Profiling of the Bcl-2/Bcl-XL-binding sites on type 1 IP3 receptor. Biochem Biophys Res Commun 2012; 428:31-5. [DOI: 10.1016/j.bbrc.2012.10.002] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2012] [Accepted: 10/01/2012] [Indexed: 02/04/2023]
|
31
|
Hamada K, Mikoshiba K. Revisiting Channel Allostery: A Coherent Mechanism in IP3 and Ryanodine Receptors. Sci Signal 2012; 5:pe24. [DOI: 10.1126/scisignal.2003148] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
|
32
|
Szlufcik K, Missiaen L, Parys JB, Callewaert G, De Smedt H. Uncoupled IP3 receptor can function as a Ca2+-leak channel: cell biological and pathological consequences. Biol Cell 2012; 98:1-14. [PMID: 16354157 DOI: 10.1042/bc20050031] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Ca(2+) release via intracellular release channels, IP(3)Rs (inositol 1,4,5-trisphosphate receptors) and RyRs (ryanodine receptors), is perhaps the most ubiquitous and versatile cellular signalling mechanism, and is involved in a vast number of cellular processes. In addition to this classical release pathway there is limited, but yet persistent, information about less well-defined Ca(2+)-leak pathways that may play an important role in the control of the Ca(2+) load of the endo(sarco)plasmic reticulum. The mechanisms responsible for this 'basal' leak are not known, but recent data suggest that both IP(3)Rs and RyRs may also operate as Ca(2+)-leak channels, particularly in pathological conditions. Proteolytic cleavage or biochemical modification (such as hyperphosphorylation or nitrosylation), for example, occurring during conditions of cell stress or apoptosis, can functionally uncouple the cytoplasmic control domains from the channel domain of the receptor. Highly significant information has been obtained from studies of malfunctioning channels in various disorders; for example, RyRs in cardiac malfunction or genetic muscle diseases and IP(3)Rs in neurodegenerative diseases. In this review we aim to summarize the existing information about functionally uncoupled IP(3)R and RyR channels, and to discuss the concept that those channels can participate in Ca(2+)-leak pathways.
Collapse
|
33
|
Abstract
The Ca(2) (+) signals evoked by inositol 1,4,5-trisphosphate (IP(3)) are built from elementary Ca(2) (+) release events involving progressive recruitment of IP(3) receptors (IP(3)R), intracellular Ca(2) (+) channels that are expressed in almost all animal cells. The smallest events ('blips') result from opening of single IP(3)R. Larger events ('puffs') reflect the near-synchronous opening of a small cluster of IP(3)R. These puffs become more frequent as the stimulus intensity increases and they eventually trigger regenerative Ca(2) (+) waves that propagate across the cell. This hierarchical recruitment of IP(3)R is important in allowing Ca(2) (+) signals to be delivered locally to specific target proteins or more globally to the entire cell. Co-regulation of IP(3)R by Ca(2) (+) and IP(3), the ability of a single IP(3)R rapidly to mediate a large efflux of Ca(2) (+) from the endoplasmic reticulum, and the assembly of IP(3)R into clusters are key features that allow IP(3)R to propagate Ca(2) (+) signals regeneratively. We review these properties of IP(3)R and the structural basis of IP(3)R behavior.
Collapse
Affiliation(s)
- Colin W Taylor
- Department of Pharmacology, Tennis Court Road, CB2 1PD, Cambridge, UK,
| | | |
Collapse
|
34
|
Parys JB, De Smedt H. Inositol 1,4,5-trisphosphate and its receptors. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2012; 740:255-79. [PMID: 22453946 DOI: 10.1007/978-94-007-2888-2_11] [Citation(s) in RCA: 89] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Activation of cells by many extracellular agonists leads to the production of inositol 1,4,5-trisphosphate (IP₃). IP₃ is a global messenger that easily diffuses in the cytosol. Its receptor (IP₃R) is a Ca(2+)-release channel located on intracellular membranes, especially the endoplasmic reticulum (ER). The IP₃R has an affinity for IP(3) in the low nanomolar range. A prime regulator of the IP₃R is the Ca(2+) ion itself. Cytosolic Ca(2+) is considered as a co-agonist of the IP₃R, as it strongly increases IP(3)R activity at concentrations up to about 300 nM. In contrast, at higher concentrations, cytosolic Ca(2+) inhibits the IP₃R. Also the luminal Ca(2+) sensitizes the IP₃R. In higher organisms three genes encode for an IP₃R and additional diversity exists as a result of alternative splicing mechanisms and the formation of homo- and heterotetramers. The various IP₃R isoforms have a similar structure and a similar function, but due to differences in their affinity for IP₃, their variable sensitivity to regulatory parameters, their differential interaction with associated proteins, and the variation in their subcellular localization, they participate differently in the formation of intracellular Ca(2+) signals and this affects therefore the physiological consequences of these signals.
Collapse
Affiliation(s)
- Jan B Parys
- Laboratory of Molecular and Cellular Signaling, Department of Cellular and Molecular Medicine, KU Leuven, Campus Gasthuisberg O/N1 - Bus 802, Herestraat 49, Belgium.
| | | |
Collapse
|
35
|
Ludtke SJ, Tran TP, Ngo QT, Moiseenkova-Bell VY, Chiu W, Serysheva II. Flexible architecture of IP3R1 by Cryo-EM. Structure 2011; 19:1192-9. [PMID: 21827954 DOI: 10.1016/j.str.2011.05.003] [Citation(s) in RCA: 74] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2011] [Revised: 04/28/2011] [Accepted: 05/02/2011] [Indexed: 11/16/2022]
Abstract
Inositol 1,4,5-trisphosphate receptors (IP3Rs) play a fundamental role in generating Ca2+ signals that trigger many cellular processes in virtually all eukaryotic cells. Thus far, the three-dimensional (3D) structure of these channels has remained extremely controversial. Here, we report a subnanometer resolution electron cryomicroscopy (cryo-EM) structure of a fully functional type 1 IP3R from cerebellum in the closed state. The transmembrane region reveals a twisted bundle of four α helices, one from each subunit, that form a funnel shaped structure around the 4-fold symmetry axis, strikingly similar to the ion-conduction pore of K+ channels. The lumenal face of IP3R1 has prominent densities that surround the pore entrance and similar to the highly structured turrets of Kir channels. 3D statistical analysis of the cryo-EM density map identifies high variance in the cytoplasmic region. This structural variation could be attributed to genuine structural flexibility of IP3R1.
Collapse
Affiliation(s)
- Steven J Ludtke
- National Center for Macromolecular Imaging, Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX 77030, USA
| | | | | | | | | | | |
Collapse
|
36
|
Baylis HA, Vázquez-Manrique RP. Genetic analysis of IP3 and calcium signalling pathways in C. elegans. Biochim Biophys Acta Gen Subj 2011; 1820:1253-68. [PMID: 22146231 DOI: 10.1016/j.bbagen.2011.11.009] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2011] [Revised: 11/15/2011] [Accepted: 11/16/2011] [Indexed: 01/02/2023]
Abstract
BACKGROUND The nematode, Caenorhabditis elegans is an established model system that is particularly well suited to genetic analysis. C. elegans is easily manipulated and we have an in depth knowledge of many aspects of its biology. Thus, it is an attractive system in which to pursue integrated studies of signalling pathways. C. elegans has a complement of calcium signalling molecules similar to that of other animals. SCOPE OF REVIEW We focus on IP3 signalling. We describe how forward and reverse genetic approaches, including RNAi, have resulted in a tool kit which enables the analysis of IP3/Ca2+ signalling pathways. The importance of cell and tissue specific manipulation of signalling pathways and the use of epistasis analysis are highlighted. We discuss how these tools have increased our understanding of IP3 signalling in specific developmental, physiological and behavioural roles. Approaches to imaging calcium signals in C. elegans are considered. MAJOR CONCLUSIONS A wide selection of tools is available for the analysis of IP3/Ca2+ signalling in C. elegans. This has resulted in detailed descriptions of the function of IP3/Ca2+ signalling in the animal's biology. Nevertheless many questions about how IP3 signalling regulates specific processes remain. GENERAL SIGNIFICANCE Many of the approaches described may be applied to other calcium signalling systems. C. elegans offers the opportunity to dissect pathways, perform integrated studies and to test the importance of the properties of calcium signalling molecules to whole animal function, thus illuminating the function of calcium signalling in animals. This article is part of a Special Issue entitled Biochemical, biophysical and genetic approaches to intracellular calcium signalling.
Collapse
Affiliation(s)
- Howard A Baylis
- Department of Zoology, University of Cambridge, Cambridge, UK.
| | | |
Collapse
|
37
|
Yamazaki H, Chan J, Ikura M, Michikawa T, Mikoshiba K. Tyr-167/Trp-168 in type 1/3 inositol 1,4,5-trisphosphate receptor mediates functional coupling between ligand binding and channel opening. J Biol Chem 2010; 285:36081-91. [PMID: 20813840 PMCID: PMC2975230 DOI: 10.1074/jbc.m110.140129] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2010] [Revised: 08/01/2010] [Indexed: 02/02/2023] Open
Abstract
The N-terminal ∼220-amino acid region of the inositol 1,4,5-trisphosphate (IP(3)) receptor (IP(3)R)/Ca(2+) release channel has been referred to as the suppressor/coupling domain because it is required for both IP(3) binding suppression and IP(3)-induced channel gating. Measurements of IP(3)-induced Ca(2+) fluxes of mutagenized mouse type 1 IP(3)R (IP(3)R1) showed that the residues responsible for IP(3) binding suppression in this domain were not essential for channel opening. On the other hand, a single amino acid substitution of Tyr-167 to alanine completely impaired IP(3)-induced Ca(2+) release without reducing the IP(3) binding activity. The corresponding residue in type 3 IP(3)R (IP(3)R3), Trp-168, was also critical for channel opening. Limited trypsin digestion experiments showed that the trypsin sensitivities of the C-terminal gatekeeper domain differed markedly between the wild-type channel and the Tyr-167 mutant under the optimal conditions for channel opening. These results strongly suggest that the Tyr/Trp residue (Tyr-167 in IP(3)R1 and Trp-168 in IP(3)R3) is critical for the functional coupling between IP(3) binding and channel gating by maintaining the structural integrity of the C-terminal gatekeeper domain at least under activation gating.
Collapse
MESH Headings
- Amino Acid Sequence
- Amino Acid Substitution
- Animals
- Binding Sites/genetics
- Blotting, Western
- Calcium/metabolism
- Cell Line, Tumor
- Inositol 1,4,5-Trisphosphate/chemistry
- Inositol 1,4,5-Trisphosphate/metabolism
- Inositol 1,4,5-Trisphosphate/pharmacology
- Inositol 1,4,5-Trisphosphate Receptors/chemistry
- Inositol 1,4,5-Trisphosphate Receptors/genetics
- Inositol 1,4,5-Trisphosphate Receptors/metabolism
- Ion Channel Gating/drug effects
- Ion Channel Gating/genetics
- Ion Channel Gating/physiology
- Ligands
- Mice
- Models, Molecular
- Molecular Sequence Data
- Mutagenesis, Site-Directed
- Mutation
- Protein Binding
- Protein Isoforms/chemistry
- Protein Isoforms/genetics
- Protein Isoforms/metabolism
- Protein Structure, Tertiary
- Sequence Homology, Amino Acid
- Trypsin/metabolism
- Tryptophan/chemistry
- Tryptophan/genetics
- Tryptophan/metabolism
- Tyrosine/chemistry
- Tyrosine/genetics
- Tyrosine/metabolism
Collapse
Affiliation(s)
- Haruka Yamazaki
- From the Laboratory for Developmental Neurobiology, RIKEN Brain Science Institute, Saitama 351-0198, Japan
- the Calcium Oscillation Project, Solution Oriented Research for Science and Technology, Japan Science and Technology Agency, Saitama 332-0012, Japan, and
| | - Jenny Chan
- the Division of Signaling Biology, Ontario Cancer Institute and Department of Medical Biophysics, University of Toronto, Ontario M5G IL7, Canada
| | - Mitsuhiko Ikura
- the Division of Signaling Biology, Ontario Cancer Institute and Department of Medical Biophysics, University of Toronto, Ontario M5G IL7, Canada
| | - Takayuki Michikawa
- From the Laboratory for Developmental Neurobiology, RIKEN Brain Science Institute, Saitama 351-0198, Japan
- the Calcium Oscillation Project, Solution Oriented Research for Science and Technology, Japan Science and Technology Agency, Saitama 332-0012, Japan, and
| | - Katsuhiko Mikoshiba
- From the Laboratory for Developmental Neurobiology, RIKEN Brain Science Institute, Saitama 351-0198, Japan
- the Calcium Oscillation Project, Solution Oriented Research for Science and Technology, Japan Science and Technology Agency, Saitama 332-0012, Japan, and
| |
Collapse
|
38
|
Taylor CW, Tovey SC. IP(3) receptors: toward understanding their activation. Cold Spring Harb Perspect Biol 2010; 2:a004010. [PMID: 20980441 DOI: 10.1101/cshperspect.a004010] [Citation(s) in RCA: 167] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Inositol 1,4,5-trisphosphate receptors (IP(3)R) and their relatives, ryanodine receptors, are the channels that most often mediate Ca(2+) release from intracellular stores. Their regulation by Ca(2+) allows them also to propagate cytosolic Ca(2+) signals regeneratively. This brief review addresses the structural basis of IP(3)R activation by IP(3) and Ca(2+). IP(3) initiates IP(3)R activation by promoting Ca(2+) binding to a stimulatory Ca(2+)-binding site, the identity of which is unresolved. We suggest that interactions of critical phosphate groups in IP(3) with opposite sides of the clam-like IP(3)-binding core cause it to close and propagate a conformational change toward the pore via the adjacent N-terminal suppressor domain. The pore, assembled from the last pair of transmembrane domains and the intervening pore loop from each of the four IP(3)R subunits, forms a structure in which a luminal selectivity filter and a gate at the cytosolic end of the pore control cation fluxes through the IP(3)R.
Collapse
Affiliation(s)
- Colin W Taylor
- Department of Pharmacology, University of Cambridge, Tennis Court Road, Cambridge, CB2 1PD, United Kingdom.
| | | |
Collapse
|
39
|
Chan J, Yamazaki H, Ishiyama N, Seo MD, Mal TK, Michikawa T, Mikoshiba K, Ikura M. Structural studies of inositol 1,4,5-trisphosphate receptor: coupling ligand binding to channel gating. J Biol Chem 2010; 285:36092-9. [PMID: 20843799 DOI: 10.1074/jbc.m110.140160] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The three isoforms of the inositol 1,4,5-trisphosphate receptor (IP(3)R) exhibit distinct IP(3) sensitivities and cooperativities in calcium (Ca(2+)) channel function. The determinants underlying this isoform-specific channel gating mechanism have been localized to the N-terminal suppressor region of IP(3)R. We determined the 1.9 Å crystal structure of the suppressor domain from type 3 IP(3)R (IP(3)R3(SUP), amino acids 1-224) and revealed structural features contributing to isoform-specific functionality of IP(3)R by comparing it with our previously determined structure of the type 1 suppressor domain (IP(3)R1(SUP)). The molecular surface known to associate with the ligand binding domain (amino acids 224-604) showed marked differences between IP(3)R3(SUP) and IP(3)R1(SUP). Our NMR and biochemical studies showed that three spatially clustered residues (Glu-20, Tyr-167, and Ser-217 in IP(3)R1 and Glu-19, Trp-168, and Ser-218 in IP(3)R3) within the N-terminal suppressor domains of IP(3)R1(SUP) and IP(3)R3(SUP) interact directly with their respective C-terminal fragments. Together with the accompanying paper (Yamazaki, H., Chan, J., Ikura, M., Michikawa, T., and Mikoshiba, K. (2010) J. Biol. Chem. 285, 36081-36091), we demonstrate that the single aromatic residue in this region (Tyr-167 in IP(3)R1 and Trp-168 in IP(3)R3) plays a critical role in the coupling between ligand binding and channel gating.
Collapse
Affiliation(s)
- Jenny Chan
- Division of Signaling Biology, Ontario Cancer Institute, Department of Medical Biophysics, University of Toronto, Toronto, Ontario M5G IL7, Canada
| | | | | | | | | | | | | | | |
Collapse
|
40
|
|
41
|
Molecular architecture of the inositol 1,4,5-trisphosphate receptor pore. CURRENT TOPICS IN MEMBRANES 2010; 66:191-207. [PMID: 22353481 DOI: 10.1016/s1063-5823(10)66009-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
|
42
|
Ding Z, Rossi AM, Riley AM, Rahman T, Potter BVL, Taylor CW. Binding of inositol 1,4,5-trisphosphate (IP3) and adenophostin A to the N-terminal region of the IP3 receptor: thermodynamic analysis using fluorescence polarization with a novel IP3 receptor ligand. Mol Pharmacol 2010; 77:995-1004. [PMID: 20215561 PMCID: PMC2879921 DOI: 10.1124/mol.109.062596] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2009] [Accepted: 03/09/2010] [Indexed: 11/22/2022] Open
Abstract
Inositol 1,4,5-trisphosphate (IP(3)) receptors (IP(3)R) are intracellular Ca(2+) channels. Their opening is initiated by binding of IP(3) to the IP(3)-binding core (IBC; residues 224-604 of IP(3)R1) and transmitted to the pore via the suppressor domain (SD; residues 1-223). The major conformational changes leading to IP(3)R activation occur within the N terminus (NT; residues 1-604). We therefore developed a high-throughput fluorescence polarization (FP) assay using a newly synthesized analog of IP(3), fluorescein isothiocyanate (FITC)-IP(3), to examine the thermodynamics of IP(3) and adenophostin A binding to the NT and IBC. Using both single-channel recording and the FP assay, we demonstrate that FITC-IP(3) is a high-affinity partial agonist of the IP(3)R. Conventional [(3)H]IP(3) and FP assays provide similar estimates of the K(D) for both IP(3) and adenophostin A in cytosol-like medium at 4 degrees C. They further establish that the isolated IBC retains the ability of full-length IP(3)R to bind adenophostin A with approximately 10-fold greater affinity than IP(3). By examining the reversible effects of temperature on ligand binding, we established that favorable entropy changes (T Delta S) account for the greater affinities of both ligands for the IBC relative to the NT and for the greater affinity of adenophostin A relative to IP(3). The two agonists differ more substantially in the relative contribution of Delta H and T Delta S to binding to the IBC relative to the NT. This suggests that different initial binding events drive the IP(3)R on convergent pathways toward a similar open state.
Collapse
Affiliation(s)
- Zhao Ding
- Department of Pharmacology, University of Cambridge, Tennis Court Road, Cambridge, CB2 1PD, United Kingdom
| | | | | | | | | | | |
Collapse
|
43
|
Yule DI, Betzenhauser MJ, Joseph SK. Linking structure to function: Recent lessons from inositol 1,4,5-trisphosphate receptor mutagenesis. Cell Calcium 2010; 47:469-79. [PMID: 20510450 DOI: 10.1016/j.ceca.2010.04.005] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2010] [Revised: 04/21/2010] [Accepted: 04/22/2010] [Indexed: 12/12/2022]
Abstract
Great insight has been gained into the structure and function of the inositol 1,4,5 trisphosphate receptor (InsP(3)R) by studies employing mutagenesis of the cDNA encoding the receptor. Notably, early studies using this approach defined the key constituents required for InsP(3) binding in the N-terminus and the membrane spanning regions in the C-terminal domain responsible for channel formation, targeting and function. In this article we evaluate recent studies which have used a similar approach to investigate key residues underlying the in vivo modulation by select regulatory factors. In addition, we review studies defining the structural requirements in the channel domain which comprise the conduction pathway and are suggested to be involved in the gating of the channel.
Collapse
Affiliation(s)
- David I Yule
- Department of Pharmacology and Physiology, University of Rochester, NY, United States.
| | | | | |
Collapse
|
44
|
Rahman T, Taylor CW. Nuclear Patch-Clamp Recording from Inositol 1,4,5-Trisphosphate Receptors. Methods Cell Biol 2010; 99:199-224. [DOI: 10.1016/b978-0-12-374841-6.00008-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
|
45
|
Taylor CW, Rahman T, Tovey SC, Dedos SG, Taylor EJA, Velamakanni S. IP3 receptors: some lessons from DT40 cells. Immunol Rev 2009; 231:23-44. [PMID: 19754888 DOI: 10.1111/j.1600-065x.2009.00807.x] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Inositol-1,4,5-trisphosphate receptors (IP3Rs) are intracellular Ca2+ channels that are regulated by IP3 and Ca2+ and are modulated by many additional signals. These properties allow them to initiate and, via Ca2+-induced Ca2+ release, regeneratively propagate Ca2+ signals evoked by receptors that stimulate formation of IP3. The ubiquitous expression of IP3R highlights their importance, but it also presents problems when attempting to resolve the behavior of defined IP3R. DT40 cells are a pre-B-lymphocyte cell line in which high rates of homologous recombination afford unrivalled opportunities to disrupt endogenous genes. DT40-knockout cells with both alleles of each of the three IP3R genes disrupted provide the only null-background for analysis of homogenous recombinant IP3R. We review the properties of DT40 cells and consider three areas where they have contributed to understanding IP3R behavior. Patch-clamp recording from the nuclear envelope and Ca2+ release from intracellular stores loaded with a low-affinity Ca2+ indicator address the mechanisms leading to activation of IP(3)R. We show that IP3 causes intracellular IP3R to cluster and re-tune their responses to IP3 and Ca2+, better equipping them to mediate regenerative Ca2+ signals. Finally, we show that DT40 cells reliably count very few IP3R into the plasma membrane, where they mediate about half the Ca2+ entry evoked by the B-cell antigen receptor.
Collapse
Affiliation(s)
- Colin W Taylor
- Department of Pharmacology, University of Cambridge, Cambridge, UK.
| | | | | | | | | | | |
Collapse
|
46
|
Rossi AM, Riley AM, Tovey SC, Taufiq-Ur-Rahman, Dellis O, Taylor EJA, Veresov VG, Potter BVL, Taylor CW. Synthetic partial agonists reveal key steps in IP3 receptor activation. Nat Chem Biol 2009; 5:631-9. [PMID: 19668195 PMCID: PMC2869033 DOI: 10.1038/nchembio.195] [Citation(s) in RCA: 65] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2009] [Accepted: 05/28/2009] [Indexed: 11/10/2022]
Abstract
Inositol 1,4,5-trisphosphate receptors (IP(3)Rs) are ubiquitous intracellular Ca2+ channels. IP(3) binding to the IP(3)-binding core (IBC) near the N terminus initiates conformational changes that lead to opening of a pore. The mechanisms underlying this process are unresolved. We synthesized 2-O-modified IP(3) analogs that are partial agonists of IP(3)R. These are similar to IP(3) in their interactions with the IBC, but they are less effective than IP(3) in rearranging the relationship between the IBC and the N-terminal suppressor domain (SD), and they open the channel at slower rates. IP(3)R with a mutation in the SD occupying a position similar to the 2-O substituent of the partial agonists has a reduced open probability that is similar for full and partial agonists. Bulky or charged substituents from either the ligand or the SD therefore block obligatory coupling of the IBC and the SD. Analysis of DeltaG for ligand binding shows that IP(3) is recognized by the IBC and conformational changes then propagate entirely via the SD to the pore.
Collapse
Affiliation(s)
- Ana M. Rossi
- Department of Pharmacology, University of Cambridge, Tennis Court Road, Cambridge, CB2 1PD, UK
| | - Andrew M. Riley
- Wolfson Laboratory of Medicinal Chemistry, Department of Pharmacy and Pharmacology, University of Bath, Claverton Down, Bath, BA2 7AY, UK
| | - Stephen C. Tovey
- Department of Pharmacology, University of Cambridge, Tennis Court Road, Cambridge, CB2 1PD, UK
| | - Taufiq-Ur-Rahman
- Department of Pharmacology, University of Cambridge, Tennis Court Road, Cambridge, CB2 1PD, UK
| | - Olivier Dellis
- Department of Pharmacology, University of Cambridge, Tennis Court Road, Cambridge, CB2 1PD, UK
| | - Emily J. A. Taylor
- Department of Pharmacology, University of Cambridge, Tennis Court Road, Cambridge, CB2 1PD, UK
| | - Valery G. Veresov
- Department of Cell Biophysics, Institute of Biophysics and Cell Engineering, Minsk 220072, Academicheskaya St. 27, Belarus
| | - Barry V. L. Potter
- Wolfson Laboratory of Medicinal Chemistry, Department of Pharmacy and Pharmacology, University of Bath, Claverton Down, Bath, BA2 7AY, UK
| | - Colin W. Taylor
- Department of Pharmacology, University of Cambridge, Tennis Court Road, Cambridge, CB2 1PD, UK
| |
Collapse
|
47
|
Taylor CW, Pantazaka E. Targeting and clustering of IP3 receptors: key determinants of spatially organized Ca2+ signals. CHAOS (WOODBURY, N.Y.) 2009; 19:037102. [PMID: 19798811 DOI: 10.1063/1.3127593] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Inositol 1,4,5-trisphosphate receptors (IP3R) are intracellular Ca2+ channels that are almost ubiquitously expressed in animal cells. The spatiotemporal complexity of the Ca2+ signals evoked by IP3R underlies their versatility in cellular signaling. Here we review the mechanisms that contribute to the subcellular targeting of IP3R and the dynamic interplay between IP3R that underpin their ability to generate complex intracellular Ca2+ signals.
Collapse
|
48
|
Vanderheyden V, Wakai T, Bultynck G, De Smedt H, Parys JB, Fissore RA. Regulation of inositol 1,4,5-trisphosphate receptor type 1 function during oocyte maturation by MPM-2 phosphorylation. Cell Calcium 2009; 46:56-64. [PMID: 19482353 PMCID: PMC2774721 DOI: 10.1016/j.ceca.2009.04.004] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2009] [Revised: 04/27/2009] [Accepted: 04/28/2009] [Indexed: 11/30/2022]
Abstract
Egg activation and further embryo development require a sperm-induced intracellular Ca(2+) signal at the time of fertilization. Prior to fertilization, the egg's Ca(2+) machinery is therefore optimized. To this end, during oocyte maturation, the sensitivity, i.e. the Ca(2+) releasing ability, of the inositol 1,4,5-trisphosphate receptor type 1 (IP(3)R1), which is responsible for most of this Ca(2+) release, markedly increases. In this study, the recently discovered specific Polo-like kinase (Plk) inhibitor BI2536 was used to investigate the role of Plk1 in this process. BI2536 inactivates Plk1 in oocytes at the early stages of maturation and significantly decreases IP(3)R1 phosphorylation at an MPM-2 epitope at this stage. Moreover, this decrease in Plk1-dependent MPM-2 phosphorylation significantly lowers IP(3)R1 sensitivity. Finally, using in vitro phosphorylation techniques we identified T(2656) as a major Plk1 site on IP(3)R1. We therefore propose that the initial increase in IP(3)R1 sensitivity during oocyte maturation is underpinned by IP(3)R1 phosphorylation at an MPM-2 epitope(s).
Collapse
Affiliation(s)
- Veerle Vanderheyden
- Laboratory of Molecular and Cellular Signalling, Department of Molecular Cell Biology, K.U. Leuven, Campus Gasthuisberg, O&N1 Bus 802, B-3000 Leuven, Belgium
| | | | | | | | | | | |
Collapse
|
49
|
Díaz-Muñoz M, de la Rosa Santander P, Juárez-Espinosa AB, Arellano RO, Morales-Tlalpan V. Granulosa cells express three inositol 1,4,5-trisphosphate receptor isoforms: cytoplasmic and nuclear Ca2+ mobilization. Reprod Biol Endocrinol 2008; 6:60. [PMID: 19068129 PMCID: PMC2631483 DOI: 10.1186/1477-7827-6-60] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/28/2008] [Accepted: 12/09/2008] [Indexed: 12/21/2022] Open
Abstract
BACKGROUND Granulosa cells play an important endocrine role in folliculogenesis. They mobilize Ca2+ from intracellular stores by a coordinated action between 1,4,5 inositol trisphosphate and ryanodine receptors (IP3R and RyR). The aim of this study was to explore the isoforms of IP3Rs expressed in mouse C57BL/6 NHsd granulosa cells, characterizing their intranuclear localization and the relation with other Ca2+-handling proteins. METHODS Ovarian tissue and granulosa cells were analyzed by multiphotonic and confocal microscopy to determine the intracellular presence of IP3R types 1, 2 and 3, RyR, thapsigargin-sensitive Ca2+-ATPase, and endomembranes. Cellular fractionation and Western blot assays were also used to further confirm the nuclear occurrence of the three IP3R isoforms. Free nuclear and cytosolic Ca2+ concentrations were measured using Fluo-4 AM by confocal microscopy. RESULTS By using antibodies and specific fluorophores, was shown that granulosa cells endomembranes contain three isoforms of IP3R, the RyR, and the thapsigargin-sensitive Ca2+-ATPase (SERCA). Interestingly, all these proteins were also detected in the nuclear envelope and in well-defined intranuclear structures. Microsomal membranes depicted characteristic bands of the 3 types of IP3R, but also variants of lower molecular weight. Analysis of nuclear membranes and nucleoplasmic fraction confirmed the nuclear localization of the IP3R types 1, 2 and 3. We demonstrated ATP-induced Ca2+ transients in the nuclear and cytoplasmic compartments. Remarkably, the inhibitory effect on ATP-induced Ca2+ mobilization of brefeldin A was more accentuated in the cytoplasm than in the nucleus. CONCLUSION These findings provide evidence that granulosa cells, including nuclei, express the Ca2+-handling proteins that allow Ca2+ mobilization. All three IP3R were also detected in ovarian slices, including the nuclei of granulosa cells, suggesting that these cells use the three IP3R in situ to achieve their physiological responses.
Collapse
Affiliation(s)
- Mauricio Díaz-Muñoz
- Departamento de Neurobiología Celular y Molecular, Instituto de Neurobiología, Campus UNAM-Juriquilla, Querétaro 76230, QRO., México
| | - Patricia de la Rosa Santander
- Departamento de Neurobiología Celular y Molecular, Instituto de Neurobiología, Campus UNAM-Juriquilla, Querétaro 76230, QRO., México
| | - Anna Berenice Juárez-Espinosa
- Departamento de Neurobiología Celular y Molecular, Instituto de Neurobiología, Campus UNAM-Juriquilla, Querétaro 76230, QRO., México
| | - Rogelio O Arellano
- Departamento de Neurobiología Celular y Molecular, Instituto de Neurobiología, Campus UNAM-Juriquilla, Querétaro 76230, QRO., México
| | - Verónica Morales-Tlalpan
- Departamento de Neurobiología Celular y Molecular, Instituto de Neurobiología, Campus UNAM-Juriquilla, Querétaro 76230, QRO., México
| |
Collapse
|
50
|
Verbert L, Lee B, Kocks SL, Assefa Z, Parys JB, Missiaen L, Callewaert G, Fissore RA, De Smedt H, Bultynck G. Caspase-3-truncated type 1 inositol 1,4,5-trisphosphate receptor enhances intracellular Ca2+ leak and disturbs Ca2+ signalling. Biol Cell 2008; 100:39-49. [PMID: 17868032 PMCID: PMC2909191 DOI: 10.1042/bc20070086] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
BACKGROUND INFORMATION The IP(3)R (inositol 1,4,5-trisphosphate receptor) is a tetrameric channel that accounts for a large part of the intracellular Ca(2+) release in virtually all cell types. We have previously demonstrated that caspase-3-mediated cleavage of IP(3)R1 during cell death generates a C-terminal fragment of 95 kDa comprising the complete channel domain. Expression of this truncated IP(3)R increases the cellular sensitivity to apoptotic stimuli, and it was postulated to be a constitutively active channel. RESULTS In the present study, we demonstrate that expression of the caspase-3-cleaved C-terminus of IP(3)R1 increased the rate of thapsigargin-mediated Ca(2+) leak and decreased the rate of Ca(2+) uptake into the ER (endoplasmic reticulum), although it was not sufficient by itself to deplete intracellular Ca(2+) stores. We detected the truncated IP(3)R1 in different cell types after a challenge with apoptotic stimuli, as well as in aged mouse oocytes. Injection of mRNA corresponding to the truncated IP(3)R1 blocked sperm factor-induced Ca(2+) oscillations and induced an apoptotic phenotype. CONCLUSIONS In the present study, we show that caspase-3-mediated truncation of IP(3)R1 enhanced the Ca(2+) leak from the ER. We suggest a model in which, in normal conditions, the increased Ca(2+) leak is largely compensated by enhanced Ca(2+)-uptake activity, whereas in situations where the cellular metabolism is compromised, as occurring in aging oocytes, the Ca(2+) leak acts as a feed-forward mechanism to divert the cell into apoptosis.
Collapse
Affiliation(s)
- Leen Verbert
- Laboratory of Molecular and Cellular Signalling, Division of Physiology, Department of Molecular Cell Biology, K.U. Leuven, Campus Gasthuisberg, O&N1 bus 802, B-3000 Leuven, Belgium
| | - Bora Lee
- Program and Department of Veterinary and Animal Sciences, University of Massachusetts, Amherst, MA 01002, U.S.A
| | - Sarah L. Kocks
- Laboratory of Molecular and Cellular Signalling, Division of Physiology, Department of Molecular Cell Biology, K.U. Leuven, Campus Gasthuisberg, O&N1 bus 802, B-3000 Leuven, Belgium
| | - Zerihun Assefa
- Laboratory of Molecular and Cellular Signalling, Division of Physiology, Department of Molecular Cell Biology, K.U. Leuven, Campus Gasthuisberg, O&N1 bus 802, B-3000 Leuven, Belgium
| | - Jan B. Parys
- Laboratory of Molecular and Cellular Signalling, Division of Physiology, Department of Molecular Cell Biology, K.U. Leuven, Campus Gasthuisberg, O&N1 bus 802, B-3000 Leuven, Belgium
| | - Ludwig Missiaen
- Laboratory of Molecular and Cellular Signalling, Division of Physiology, Department of Molecular Cell Biology, K.U. Leuven, Campus Gasthuisberg, O&N1 bus 802, B-3000 Leuven, Belgium
| | - Geert Callewaert
- Laboratory of Molecular and Cellular Signalling, Division of Physiology, Department of Molecular Cell Biology, K.U. Leuven, Campus Gasthuisberg, O&N1 bus 802, B-3000 Leuven, Belgium
| | - Rafael A. Fissore
- Program and Department of Veterinary and Animal Sciences, University of Massachusetts, Amherst, MA 01002, U.S.A
| | - Humbert De Smedt
- Laboratory of Molecular and Cellular Signalling, Division of Physiology, Department of Molecular Cell Biology, K.U. Leuven, Campus Gasthuisberg, O&N1 bus 802, B-3000 Leuven, Belgium
| | - Geert Bultynck
- Laboratory of Molecular and Cellular Signalling, Division of Physiology, Department of Molecular Cell Biology, K.U. Leuven, Campus Gasthuisberg, O&N1 bus 802, B-3000 Leuven, Belgium
- To whom correspondence should be addressed ()
| |
Collapse
|