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Kowalski A, Betzer C, Larsen ST, Gregersen E, Newcombe EA, Bermejo MC, Bendtsen VW, Diemer J, Ernstsen CV, Jain S, Bou AE, Langkilde AE, Nejsum LN, Klipp E, Edwards R, Kragelund BB, Jensen PH, Nissen P. Monomeric α-synuclein activates the plasma membrane calcium pump. EMBO J 2023; 42:e111122. [PMID: 37916890 PMCID: PMC10690453 DOI: 10.15252/embj.2022111122] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2022] [Revised: 09/19/2023] [Accepted: 10/11/2023] [Indexed: 11/03/2023] Open
Abstract
Alpha-synuclein (aSN) is a membrane-associated and intrinsically disordered protein, well known for pathological aggregation in neurodegeneration. However, the physiological function of aSN is disputed. Pull-down experiments have pointed to plasma membrane Ca2+ -ATPase (PMCA) as a potential interaction partner. From proximity ligation assays, we find that aSN and PMCA colocalize at neuronal synapses, and we show that calcium expulsion is activated by aSN and PMCA. We further show that soluble, monomeric aSN activates PMCA at par with calmodulin, but independent of the autoinhibitory domain of PMCA, and highly dependent on acidic phospholipids and membrane-anchoring properties of aSN. On PMCA, the key site is mapped to the acidic lipid-binding site, located within a disordered PMCA-specific loop connecting the cytosolic A domain and transmembrane segment 3. Our studies point toward a novel physiological role of monomeric aSN as a stimulator of calcium clearance in neurons through activation of PMCA.
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Affiliation(s)
- Antoni Kowalski
- Department of Molecular Biology and GeneticsAarhus UniversityAarhusDenmark
- Danish Research Institute of Translational Neuroscience – DANDRITEAarhus UniversityAarhusDenmark
- REPIN and Structural Biology and NMR Laboratory, Department of BiologyUniversity of CopenhagenCopenhagenDenmark
- Department of Molecular NeurochemistryMedical University of LodzLodzPoland
- Present address:
ImmunAware ApSHørsholmDenmark
| | - Cristine Betzer
- Danish Research Institute of Translational Neuroscience – DANDRITEAarhus UniversityAarhusDenmark
- Department of BiomedicineAarhus UniversityAarhusDenmark
- Present address:
Region Midtjylland, Regionshospitalet GødstrupHerningDenmark
| | - Sigrid Thirup Larsen
- Department of Molecular Biology and GeneticsAarhus UniversityAarhusDenmark
- Danish Research Institute of Translational Neuroscience – DANDRITEAarhus UniversityAarhusDenmark
| | - Emil Gregersen
- Danish Research Institute of Translational Neuroscience – DANDRITEAarhus UniversityAarhusDenmark
- Department of BiomedicineAarhus UniversityAarhusDenmark
- Present address:
Department of Clinical MedicineAarhus UniversityAarhus NDenmark
| | - Estella A Newcombe
- REPIN and Structural Biology and NMR Laboratory, Department of BiologyUniversity of CopenhagenCopenhagenDenmark
| | - Montaña Caballero Bermejo
- Department of Molecular Biology and GeneticsAarhus UniversityAarhusDenmark
- Danish Research Institute of Translational Neuroscience – DANDRITEAarhus UniversityAarhusDenmark
- Department Biochemistry and Molecular Biology and Genetics, IBMPUniversity of ExtremaduraBadajozSpain
| | - Viktor Wisniewski Bendtsen
- Department of Molecular Biology and GeneticsAarhus UniversityAarhusDenmark
- Danish Research Institute of Translational Neuroscience – DANDRITEAarhus UniversityAarhusDenmark
| | - Jorin Diemer
- Theoretical BiophysicsHumboldt‐Universität zu BerlinBerlinGermany
| | | | - Shweta Jain
- Departments of Neurology and PhysiologyUniversity of California San FranciscoSan FranciscoCAUSA
| | - Alicia Espiña Bou
- Department of Molecular Biology and GeneticsAarhus UniversityAarhusDenmark
- Danish Research Institute of Translational Neuroscience – DANDRITEAarhus UniversityAarhusDenmark
| | | | - Lene N Nejsum
- Department of Clinical MedicineAarhus UniversityAarhus NDenmark
| | - Edda Klipp
- Theoretical BiophysicsHumboldt‐Universität zu BerlinBerlinGermany
| | - Robert Edwards
- Departments of Neurology and PhysiologyUniversity of California San FranciscoSan FranciscoCAUSA
| | - Birthe B Kragelund
- REPIN and Structural Biology and NMR Laboratory, Department of BiologyUniversity of CopenhagenCopenhagenDenmark
| | - Poul Henning Jensen
- Danish Research Institute of Translational Neuroscience – DANDRITEAarhus UniversityAarhusDenmark
- Department of BiomedicineAarhus UniversityAarhusDenmark
| | - Poul Nissen
- Department of Molecular Biology and GeneticsAarhus UniversityAarhusDenmark
- Danish Research Institute of Translational Neuroscience – DANDRITEAarhus UniversityAarhusDenmark
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2
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Hua T, Robitaille M, Roberts-Thomson SJ, Monteith GR. The intersection between cysteine proteases, Ca 2+ signalling and cancer cell apoptosis. BIOCHIMICA ET BIOPHYSICA ACTA. MOLECULAR CELL RESEARCH 2023; 1870:119532. [PMID: 37393017 DOI: 10.1016/j.bbamcr.2023.119532] [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: 04/03/2023] [Revised: 06/19/2023] [Accepted: 06/26/2023] [Indexed: 07/03/2023]
Abstract
Apoptosis is a highly complex and regulated cell death pathway that safeguards the physiological balance between life and death. Over the past decade, the role of Ca2+ signalling in apoptosis and the mechanisms involved have become clearer. The initiation and execution of apoptosis is coordinated by three distinct groups of cysteines proteases: the caspase, calpain and cathepsin families. Beyond its physiological importance, the ability to evade apoptosis is a prominent hallmark of cancer cells. In this review, we will explore the involvement of Ca2+ in the regulation of caspase, calpain and cathepsin activity, and how the actions of these cysteine proteases alter intracellular Ca2+ handling during apoptosis. We will also explore how apoptosis resistance can be achieved in cancer cells through deregulation of cysteine proteases and remodelling of the Ca2+ signalling toolkit.
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Affiliation(s)
- Trinh Hua
- School of Pharmacy, The University of Queensland, Brisbane, QLD 4102, Australia.
| | - Mélanie Robitaille
- School of Pharmacy, The University of Queensland, Brisbane, QLD 4102, Australia.
| | | | - Gregory R Monteith
- School of Pharmacy, The University of Queensland, Brisbane, QLD 4102, Australia; Mater Research Institute, Translational Research Institute, The University of Queensland, Brisbane, QLD, Australia.
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3
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Kimura M, Mochizuki H, Satou R, Iwasaki M, Kokubu E, Kono K, Nomura S, Sakurai T, Kuroda H, Shibukawa Y. Plasma Membrane Ca 2+-ATPase in Rat and Human Odontoblasts Mediates Dentin Mineralization. Biomolecules 2021; 11:biom11071010. [PMID: 34356633 PMCID: PMC8301758 DOI: 10.3390/biom11071010] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2021] [Revised: 06/28/2021] [Accepted: 07/05/2021] [Indexed: 11/17/2022] Open
Abstract
Intracellular Ca2+ signaling engendered by Ca2+ influx and mobilization in odontoblasts is critical for dentinogenesis induced by multiple stimuli at the dentin surface. Increased Ca2+ is exported by the Na+–Ca2+ exchanger (NCX) and plasma membrane Ca2+–ATPase (PMCA) to maintain Ca2+ homeostasis. We previously demonstrated a functional coupling between Ca2+ extrusion by NCX and its influx through transient receptor potential channels in odontoblasts. Although the presence of PMCA in odontoblasts has been previously described, steady-state levels of mRNA-encoding PMCA subtypes, pharmacological properties, and other cellular functions remain unclear. Thus, we investigated PMCA mRNA levels and their contribution to mineralization under physiological conditions. We also examined the role of PMCA in the Ca2+ extrusion pathway during hypotonic and alkaline stimulation-induced increases in intracellular free Ca2+ concentration ([Ca2+]i). We performed RT-PCR and mineralization assays in human odontoblasts. [Ca2+]i was measured using fura-2 fluorescence measurements in odontoblasts isolated from newborn Wistar rat incisor teeth and human odontoblasts. We detected mRNA encoding PMCA1–4 in human odontoblasts. The application of hypotonic or alkaline solutions transiently increased [Ca2+]i in odontoblasts in both rat and human odontoblasts. The Ca2+ extrusion efficiency during the hypotonic or alkaline solution-induced [Ca2+]i increase was decreased by PMCA inhibitors in both cell types. Alizarin red and von Kossa staining showed that PMCA inhibition suppressed mineralization. In addition, alkaline stimulation (not hypotonic stimulation) to human odontoblasts upregulated the mRNA levels of dentin matrix protein-1 (DMP-1) and dentin sialophosphoprotein (DSPP). The PMCA inhibitor did not affect DMP-1 or DSPP mRNA levels at pH 7.4–8.8 and under isotonic and hypotonic conditions, respectively. We also observed PMCA1 immunoreactivity using immunofluorescence analysis. These findings indicate that PMCA participates in maintaining [Ca2+]i homeostasis in odontoblasts by Ca2+ extrusion following [Ca2+]i elevation. In addition, PMCA participates in dentinogenesis by transporting Ca2+ to the mineralizing front (which is independent of non-collagenous dentin matrix protein secretion) under physiological and pathological conditions following mechanical stimulation by hydrodynamic force inside dentinal tubules, or direct alkaline stimulation by the application of high-pH dental materials.
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Affiliation(s)
- Maki Kimura
- Department of Physiology, Tokyo Dental College, 2-9-18, Kanda-Misaki-cho, Chiyoda-ku, Tokyo 101-0061, Japan; (M.K.); (H.M.); (K.K.); (S.N.); (T.S.); (H.K.)
| | - Hiroyuki Mochizuki
- Department of Physiology, Tokyo Dental College, 2-9-18, Kanda-Misaki-cho, Chiyoda-ku, Tokyo 101-0061, Japan; (M.K.); (H.M.); (K.K.); (S.N.); (T.S.); (H.K.)
| | - Ryouichi Satou
- Department of Epidemiology and Public Health, Tokyo Dental College, Chiyodaku, Tokyo 101-0061, Japan; (R.S.); (M.I.)
| | - Miyu Iwasaki
- Department of Epidemiology and Public Health, Tokyo Dental College, Chiyodaku, Tokyo 101-0061, Japan; (R.S.); (M.I.)
| | - Eitoyo Kokubu
- Department of Microbiology, Tokyo Dental College, Chiyodaku, Tokyo 101-0061, Japan;
| | - Kyosuke Kono
- Department of Physiology, Tokyo Dental College, 2-9-18, Kanda-Misaki-cho, Chiyoda-ku, Tokyo 101-0061, Japan; (M.K.); (H.M.); (K.K.); (S.N.); (T.S.); (H.K.)
| | - Sachie Nomura
- Department of Physiology, Tokyo Dental College, 2-9-18, Kanda-Misaki-cho, Chiyoda-ku, Tokyo 101-0061, Japan; (M.K.); (H.M.); (K.K.); (S.N.); (T.S.); (H.K.)
| | - Takeshi Sakurai
- Department of Physiology, Tokyo Dental College, 2-9-18, Kanda-Misaki-cho, Chiyoda-ku, Tokyo 101-0061, Japan; (M.K.); (H.M.); (K.K.); (S.N.); (T.S.); (H.K.)
| | - Hidetaka Kuroda
- Department of Physiology, Tokyo Dental College, 2-9-18, Kanda-Misaki-cho, Chiyoda-ku, Tokyo 101-0061, Japan; (M.K.); (H.M.); (K.K.); (S.N.); (T.S.); (H.K.)
- Department of Dental Anesthesiology, Kanagawa Dental University, 1-23, Ogawacho, Kanagawa, Yokosuka-shi 238-8570, Japan
| | - Yoshiyuki Shibukawa
- Department of Physiology, Tokyo Dental College, 2-9-18, Kanda-Misaki-cho, Chiyoda-ku, Tokyo 101-0061, Japan; (M.K.); (H.M.); (K.K.); (S.N.); (T.S.); (H.K.)
- Correspondence:
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Takvam M, Wood CM, Kryvi H, Nilsen TO. Ion Transporters and Osmoregulation in the Kidney of Teleost Fishes as a Function of Salinity. Front Physiol 2021; 12:664588. [PMID: 33967835 PMCID: PMC8098666 DOI: 10.3389/fphys.2021.664588] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2021] [Accepted: 03/24/2021] [Indexed: 12/13/2022] Open
Abstract
Euryhaline teleosts exhibit major changes in renal function as they move between freshwater (FW) and seawater (SW) environments, thus tolerating large fluctuations in salinity. In FW, the kidney excretes large volumes of water through high glomerular filtration rates (GFR) and low tubular reabsorption rates, while actively reabsorbing most ions at high rates. The excreted product has a high urine flow rate (UFR) with a dilute composition. In SW, GFR is greatly reduced, and the tubules reabsorb as much water as possible, while actively secreting divalent ions. The excreted product has a low UFR, and is almost isosmotic to the blood plasma, with Mg2+, SO42–, and Cl– as the major ionic components. Early studies at the organismal level have described these basic patterns, while in the last two decades, studies of regulation at the cell and molecular level have been implemented, though only in a few euryhaline groups (salmonids, eels, tilapias, and fugus). There have been few studies combining the two approaches. The aim of the review is to integrate known aspects of renal physiology (reabsorption and secretion) with more recent advances in molecular water and solute physiology (gene and protein function of transporters). The renal transporters addressed include the subunits of the Na+, K+- ATPase (NKA) enzyme, monovalent ion transporters for Na+, Cl–, and K+ (NKCC1, NKCC2, CLC-K, NCC, ROMK2), water transport pathways [aquaporins (AQP), claudins (CLDN)], and divalent ion transporters for SO42–, Mg2+, and Ca2+ (SLC26A6, SLC26A1, SLC13A1, SLC41A1, CNNM2, CNNM3, NCX1, NCX2, PMCA). For each transport category, we address the current understanding at the molecular level, try to synthesize it with classical knowledge of overall renal function, and highlight knowledge gaps. Future research on the kidney of euryhaline fishes should focus on integrating changes in kidney reabsorption and secretion of ions with changes in transporter function at the cellular and molecular level (gene and protein verification) in different regions of the nephrons. An increased focus on the kidney individually and its functional integration with the other osmoregulatory organs (gills, skin and intestine) in maintaining overall homeostasis will have applied relevance for aquaculture.
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Affiliation(s)
- Marius Takvam
- Department of Biological Sciences, University of Bergen, Bergen, Norway.,NORCE, Norwegian Research Centre, NORCE Environment, Bergen, Norway
| | - Chris M Wood
- Department of Zoology, University of British Columbia, Vancouver, BC, Canada
| | - Harald Kryvi
- Department of Biological Sciences, University of Bergen, Bergen, Norway
| | - Tom O Nilsen
- Department of Biological Sciences, University of Bergen, Bergen, Norway.,NORCE, Norwegian Research Centre, NORCE Environment, Bergen, Norway
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5
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Rimessi A, Vitto VAM, Patergnani S, Pinton P. Update on Calcium Signaling in Cystic Fibrosis Lung Disease. Front Pharmacol 2021; 12:581645. [PMID: 33776759 PMCID: PMC7990772 DOI: 10.3389/fphar.2021.581645] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2020] [Accepted: 01/19/2021] [Indexed: 12/15/2022] Open
Abstract
Cystic fibrosis (CF) is an autosomal recessive disorder characterized by mutations in the cystic fibrosis transmembrane conductance regulator gene, which causes multifunctional defects that preferentially affect the airways. Abnormal viscosity of mucus secretions, persistent pathogen infections, hyperinflammation, and lung tissue damage compose the classical pathological manifestation referred to as CF lung disease. Among the multifunctional defects associated with defective CFTR, increasing evidence supports the relevant role of perturbed calcium (Ca2+) signaling in the pathophysiology of CF lung disease. The Ca2+ ion is a critical player in cell functioning and survival. Its intracellular homeostasis is maintained by a fine balance between channels, transporters, and exchangers, mediating the influx and efflux of the ion across the plasma membrane and the intracellular organelles. An abnormal Ca2+ profile has been observed in CF cells, including airway epithelial and immune cells, with heavy repercussions on cell function, viability, and susceptibility to pathogens, contributing to proinflammatory overstimulation, organelle dysfunction, oxidative stress, and excessive cytokines release in CF lung. This review discusses the role of Ca2+ signaling in CF and how its dysregulation in airway epithelial and immune cells contributes to hyperinflammation in the CF lung. Finally, we provide an outlook on the therapeutic options that target the Ca2+ signaling to treat the CF lung disease.
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Affiliation(s)
- Alessandro Rimessi
- Department of Medical Sciences and Laboratory for Technologies of Advanced Therapies (LTTA), University of Ferrara, Ferrara, Italy.,Center of Research for Innovative Therapies in Cystic Fibrosis, University of Ferrara, Ferrara, Italy
| | - Veronica A M Vitto
- Department of Medical Sciences and Laboratory for Technologies of Advanced Therapies (LTTA), University of Ferrara, Ferrara, Italy
| | - Simone Patergnani
- Department of Medical Sciences and Laboratory for Technologies of Advanced Therapies (LTTA), University of Ferrara, Ferrara, Italy
| | - Paolo Pinton
- Department of Medical Sciences and Laboratory for Technologies of Advanced Therapies (LTTA), University of Ferrara, Ferrara, Italy.,Center of Research for Innovative Therapies in Cystic Fibrosis, University of Ferrara, Ferrara, Italy
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6
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Chamberland S, Zamora Moratalla A, Topolnik L. Calcium extrusion mechanisms in dendrites of mouse hippocampal CA1 inhibitory interneurons. Cell Calcium 2019; 77:49-57. [DOI: 10.1016/j.ceca.2018.12.002] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2018] [Revised: 11/25/2018] [Accepted: 12/03/2018] [Indexed: 12/18/2022]
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7
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Sillanpää JK, Sundh H, Sundell KS. Calcium transfer across the outer mantle epithelium in the Pacific oyster, Crassostrea gigas. Proc Biol Sci 2018; 285:20181676. [PMID: 30429301 PMCID: PMC6253367 DOI: 10.1098/rspb.2018.1676] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2018] [Accepted: 10/24/2018] [Indexed: 11/12/2022] Open
Abstract
Calcium transport is essential for bivalves to be able to build and maintain their shells. Ionized calcium (Ca2+) is taken up from the environment and eventually transported through the outer mantle epithelium (OME) to the shell growth area. However, the mechanisms behind this process are poorly understood. The objective of the present study was to characterize the Ca2+ transfer performed by the OME of the Pacific oyster, Crassostrea gigas, as well as to develop an Ussing chamber technique for the functional assessment of transport activities in epithelia of marine bivalves. Kinetic studies revealed that the Ca2+ transfer across the OME consists of one saturable and one linear component, of which the saturable component fits best to Michaelis-Menten kinetics and is characterized by a Km of 6.2 mM and a Vmax of 3.3 nM min-1 The transcellular transfer of Ca2+ accounts for approximately 60% of the total Ca2+ transfer across the OME of C. gigas at environmental Ca2+ concentrations. The use of the pharmacological inhibitors: verapamil, ouabain and caloxin 1a1 revealed that voltage-gated Ca2+-channels, plasma-membrane Ca2+-ATPase and Na+/Ca2+-exchanger all participate in the transcellular Ca2+ transfer across the OME and a model for this Ca2+ transfer is presented and discussed.
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Affiliation(s)
- J Kirsikka Sillanpää
- Department of Biological and Environmental Sciences, Swedish Mariculture Research Center, University of Gothenburg, Box 463, Gothenburg 40530, Sweden
| | - Henrik Sundh
- Department of Biological and Environmental Sciences, Swedish Mariculture Research Center, University of Gothenburg, Box 463, Gothenburg 40530, Sweden
| | - Kristina S Sundell
- Department of Biological and Environmental Sciences, Swedish Mariculture Research Center, University of Gothenburg, Box 463, Gothenburg 40530, Sweden
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8
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Vinaiphat A, Thongboonkerd V. Characterizations of PMCA2-interacting complex and its role as a calcium oxalate crystal-binding protein. Cell Mol Life Sci 2018; 75:1461-1482. [PMID: 29085954 PMCID: PMC11105569 DOI: 10.1007/s00018-017-2699-2] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2017] [Revised: 10/24/2017] [Accepted: 10/26/2017] [Indexed: 12/27/2022]
Abstract
Three isoforms of plasma membrane Ca2+-ATPase (PMCA) are expressed in the kidney. While PMCA1 and PMCA4 play major role in regulating Ca2+ reabsorption, the role for PMCA2 remains vaguely defined. To define PMCA2 function, PMCA2-interacting complex was characterized by immunoprecipitation followed by nanoLC-ESI-Qq-TripleTOF MS/MS (IP-MS). After subtracting non-specific binders using isotype-controlled IP-MS, 474 proteins were identified as PMCA2-interacting partners. Among these, eight were known and 20 were potential PMCA2-interacting partners based on bioinformatic prediction, whereas other 446 were novel and had not been previously reported/predicted. Quantitative immuno-co-localization assay confirmed the association of PMCA2 with these partners. Gene ontology analysis revealed binding activity as the major molecular function of PMCA2-interacting complex. Functional validation using calcium oxalate monohydrate (COM) crystal-protein binding, crystal-cell adhesion, and crystal internalization assays together with neutralization by anti-PMCA2 antibody compared to isotype-controlled IgG and blank control, revealed a novel role of PMCA2 as a COM crystal-binding protein that was crucial for crystal retention and uptake. In summary, a large number of novel PMCA2-interacting proteins have been defined and a novel function of PMCA2 as a COM crystal-binding protein sheds light onto its involvement, at least in part, in kidney stone pathogenesis.
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Affiliation(s)
- Arada Vinaiphat
- Medical Proteomics Unit, Office for Research and Development, Faculty of Medicine Siriraj Hospital, Mahidol University, 6th Floor-SiMR Building, 2 Wanglang Road, Bangkoknoi, Bangkok, 10700, Thailand
- Center for Research in Complex Systems Science, Mahidol University, Bangkok, Thailand
| | - Visith Thongboonkerd
- Medical Proteomics Unit, Office for Research and Development, Faculty of Medicine Siriraj Hospital, Mahidol University, 6th Floor-SiMR Building, 2 Wanglang Road, Bangkoknoi, Bangkok, 10700, Thailand.
- Center for Research in Complex Systems Science, Mahidol University, Bangkok, Thailand.
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9
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Regulation of the Plasma Membrane Calcium ATPases by the actin cytoskeleton. Biochem Biophys Res Commun 2017; 506:347-354. [PMID: 29180009 DOI: 10.1016/j.bbrc.2017.11.151] [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: 11/17/2017] [Accepted: 11/22/2017] [Indexed: 01/08/2023]
Abstract
Associations between the cortical cytoskeleton and the components of the plasma membrane are no longer considered to be merely of structural and mechanical nature but are nowadays recognized as dynamic interactions that modulate a plethora of cellular responses. Reorganization of actin filaments upon diverse stimuli - among which is the rise in cytosolic Ca2+ - is involved in cell motility and adhesion, phagocytosis, cytokinesis, and secretion. Actin dynamics also participates in the regulation of ion transport across the membranes where it not only plays a key role in the delivery and stabilization of channels and transporters in the plasma membrane but also in the regulation of their activity. The recently described functional interaction between actin and the Plasma Membrane Ca2+-ATPase (PMCA) represents a novel regulatory mechanism of the pump at the time that unveils a new pathway by which the cortical actin cytoskeleton participates in the regulation of cytosolic Ca2+ homeostasis. In this review, we summarize the current knowledge on the interaction between the cortical actin cytoskeleton and the PMCA and discuss the possible mechanisms that may explain the pump's modulation.
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10
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Zhang WB, Kwan CY. Pharmacological evidence that potentiation of plasmalemmal Ca(2+)-extrusion is functionally coupled to inhibition of SR Ca(2+)-ATPases in vascular smooth muscle cells. Naunyn Schmiedebergs Arch Pharmacol 2016; 389:447-55. [PMID: 26842648 DOI: 10.1007/s00210-016-1209-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2015] [Accepted: 01/05/2016] [Indexed: 11/28/2022]
Abstract
Cyclopiazonic acid (CPA), a specific inhibitor of sarcoplasmic reticulum (SR) Ca(2+)-ATPases, causes slowly developing and subsequently diminishing characteristic contractions in vascular smooth muscle, and the second application of CPA has incompletely repeatable effects, depending on the vessel type. The objective of the present study was to examine the mechanisms underlying the significant decrease of CPA-induced contractions upon the second application. A pharmacological intervention of Ca(2+) extrusion process as a strategy was performed to modulate vasoconstrictor effects of CPA in rat aortic ring preparations. CPA-induced contractions, expressed as percentages of the contractions induced by KCl (80 mM), were significantly decreased from 44.1 ± 5.7 to 7.6 ± 1.8 % (P < 0.001) upon the second application. The contractions, however, were completely repeatable in the presence of vanadate, an inhibitor of ATPases, but not of ouabain, an inhibitor of Na(+)-pumps. Strikingly, CPA-induced contractions were sustained and completely repeatable in Na(+)-free and low Na(+) medium. Furthermore, we found that the contractions were completely repeatable in the presence of 2',4'-dichlorobenzamil, an inhibitor of the forward mode of Na(+)/Ca(2+) exchangers, but not of KBR7943, an inhibitor of the reverse mode of Na(+)/Ca(2+) exchangers. Our findings indicate that CPA by inducing a transient rise in cytosolic Ca(2+) level causes a long-lasting upregulation of plasma membrane (PM) Ca(2+) extruders and thus leads to a diminished contraction upon its second application in blood vessels. This suggests that there is a functional coupling between PM Ca(2+) extruders and SR Ca(2+)-ATPases in rat aortic smooth muscle cells.
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Affiliation(s)
- Wen-Bo Zhang
- Department of Medicine, Faculty of Health Sciences, McMaster University, 1200 Main Street West, Hamilton, ON, L8N 3Z5, Canada.,Program in Neurosciences & Mental Health, The Hospital for Sick Children, 686 Bay Street, Toronto, ON, M5G 0A4, Canada
| | - Chiu-Yin Kwan
- Department of Medicine, Faculty of Health Sciences, McMaster University, 1200 Main Street West, Hamilton, ON, L8N 3Z5, Canada. .,Vascular Biology Research Group and Research Institute of Basic Medical Science, School of Medicine, China Medical University, Taichung, Taiwan, 40402.
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Abstract
Na(+)/Ca(2+) exchangers (NCXs) have traditionally been viewed principally as a means of Ca(2+) removal from non-excitable cells. However there has recently been increasing interest in the operation of NCXs in reverse mode acting as a means of eliciting Ca(2+) entry into these cells. Reverse mode exchange requires a significant change in the normal resting transmembrane ion gradients and membrane potential, which has been suggested to occur principally via the coupling of NCXs to localised Na(+) entry through non-selective cation channels such as canonical transient receptor potential (TRPC) channels. Here we review evidence for functional or physical coupling of NCXs to non-selective cation channels, and how this affects NCX activity in non-excitable cells. In particular we focus on the potential role of nanojunctions, where the close apposition of plasma and intracellular membranes may help create the conditions needed for the generation of localised rises in Na(+) concentration that would be required to trigger reverse mode exchange.
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12
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Pászty K, Caride AJ, Bajzer Ž, Offord CP, Padányi R, Hegedűs L, Varga K, Strehler EE, Enyedi A. Plasma membrane Ca2+-ATPases can shape the pattern of Ca2+transients induced by store-operated Ca2+entry. Sci Signal 2015; 8:ra19. [DOI: 10.1126/scisignal.2005672] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
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13
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Kosiorek M, Podszywalow-Bartnicka P, Zylinska L, Pikula S. NFAT1 and NFAT3 cooperate with HDAC4 during regulation of alternative splicing of PMCA isoforms in PC12 cells. PLoS One 2014; 9:e99118. [PMID: 24905014 PMCID: PMC4048221 DOI: 10.1371/journal.pone.0099118] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2014] [Accepted: 05/10/2014] [Indexed: 02/07/2023] Open
Abstract
Background The bulk of human genes undergo alternative splicing (AS) upon response to physiological stimuli. AS is a great source of protein diversity and biological processes and is associated with the development of many diseases. Pheochromocytoma is a neuroendocrine tumor, characterized by an excessive Ca2+-dependent secretion of catecholamines. This underlines the importance of balanced control of calcium transport via regulation of gene expression pattern, including different calcium transport systems, such as plasma membrane Ca2+-ATPases (PMCAs), abundantly expressed in pheochromocytoma chromaffin cells (PC12 cells). PMCAs are encoded by four genes (Atp2b1, Atp2b2, Atp2b3, Atp2b4), whose transcript products undergo alternative splicing giving almost 30 variants. Results In this scientific report, we propose a novel mechanism of regulation of PMCA alternative splicing in PC12 cells through cooperation of the nuclear factor of activated T-cells (NFAT) and histone deacetylases (HDACs). Luciferase assays showed increased activity of NFAT in PC12 cells, which was associated with altered expression of PMCA. RT-PCR experiments suggested that inhibition of the transcriptional activity of NFAT might result in the rearrangement of PMCA splicing variants in PC12 cells. NFAT inhibition led to dominant expression of 2x/c, 3x/a and 4x/a PMCA variants, while in untreated cells the 2w,z/b, 3z,x/b,c,e,f, and 4x/b variants were found as well. Furthermore, chromatin immunoprecipitation experiments showed that NFAT1-HDAC4 or NFAT3-HDAC4 complexes might be involved in regulation of PMCA2x splicing variant generation. Conclusions We suggest that the influence of NFAT/HDAC on PMCA isoform composition might be important for altered dopamine secretion by PC12 cells.
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Affiliation(s)
- Michalina Kosiorek
- Department of Biochemistry, Nencki Institute of Experimental Biology, Warsaw, Poland
- Department of Neurodegenerative Disorders, Laboratory of Neurogenetics, Mossakowski Medical Research Centre PAS, Warsaw, Poland
| | | | - Ludmila Zylinska
- Department of Molecular Neurochemistry, Medical University, Lodz, Poland
| | - Slawomir Pikula
- Department of Biochemistry, Nencki Institute of Experimental Biology, Warsaw, Poland
- * E-mail:
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Kosiorek M, Zylinska L, Zablocki K, Pikula S. Calcineurin/NFAT signaling represses genes Vamp1 and Vamp2 via PMCA-dependent mechanism during dopamine secretion by Pheochromocytoma cells. PLoS One 2014; 9:e92176. [PMID: 24667359 PMCID: PMC3965406 DOI: 10.1371/journal.pone.0092176] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2013] [Accepted: 02/19/2014] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Plasma membrane Ca(2+)-ATPases (PMCA) extrude Ca(2+) ions out of the cell and contribute to generation of calcium oscillations. Calcium signaling is crucial for transcriptional regulation of dopamine secretion by neuroendocrine PC12 cells. Low resting [Ca(2+)]c in PC12 cells is maintained mainly by two Ca(2+)-ATPases, PMCA2 and PMCA3. Recently, we found that Ca(2+) dependent phosphatase calcineurin was excessively activated under conditions of experimental downregulation of PMCA2 or PMCA3. Thus, the aim of this study was to explain if, via modulation of the Ca(2+)/calcineurin-dependent nuclear factor of activated T cells (NFAT) pathway, PMCA2 and PMCA3 affect intracellular signaling in pheochromocytoma/neuronal cells/PC12 cells. Secondly, we tested whether this might influence dopamine secretion by PC12 cells. RESULTS PMCA2- and PMCA3-deficient cells displayed profound decrease in dopamine secretion accompanied by a permanent increase in [Ca(2+)]c. Reduction in secretion might result from changes in NFAT signaling, following altered PMCA pattern. Consequently, activation of NFAT1 and NFAT3 transcription factors was observed in PMCA2- or PMCA3-deficient cells. Furthermore, chromatin immunoprecipitation assay indicated that NFATs could be involved in repression of Vamp genes encoding vesicle associated membrane proteins (VAMP). CONCLUSIONS PMCA2 and PMCA3 are crucial for dopamine secretion in PC12 cells. Reduction in PMCA2 or PMCA3 led to calcium-dependent activation of calcineurin/NFAT signaling and, in consequence, to repression of the Vamp gene and deterioration of the SNARE complex formation in PC12 cells.
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Affiliation(s)
- Michalina Kosiorek
- Department of Biochemistry, Nencki Institute of Experimental Biology, PAS, Warsaw, Poland
- Laboratory of Neurogenetics, Department of Neurodegenerative Disorders, Mossakowski Medical Research Centre PAS, Warsaw, Poland
- * E-mail: (MK); (SP)
| | - Ludmila Zylinska
- Department of Molecular Neurochemistry, Medical University, Lodz, Poland
| | - Krzysztof Zablocki
- Department of Biochemistry, Nencki Institute of Experimental Biology, PAS, Warsaw, Poland
| | - Slawomir Pikula
- Department of Biochemistry, Nencki Institute of Experimental Biology, PAS, Warsaw, Poland
- * E-mail: (MK); (SP)
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Wright LN, Ryscavage A, Merlino G, Yuspa SH. Modeling the transcriptional consequences of epidermal growth factor receptor ablation in Ras-initiated squamous cancer. Clin Cancer Res 2011; 18:170-83. [PMID: 22068661 DOI: 10.1158/1078-0432.ccr-11-1349] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
PURPOSE Epidermal growth factor receptor (EGFR)-targeted therapy is in clinical use to treat squamous cell carcinoma of the head and neck and other cancers of lining epithelium. RAS mutations in these tumors are a negative prognostic factor for response, and skin inflammation is an adverse reaction to therapy. We investigated transcriptional and biochemical changes that could account for the confounding effects of RAS activation and inflammation in a squamous tissue. EXPERIMENTAL DESIGN We carried out gene expression profiling on oncogenic Ras-transformed and wild-type mouse and human keratinocytes with EGFR ablated chronically by genetic deletion or acutely by drug treatment and followed leads provided by pathway analysis with biochemical studies. RESULTS We identified a 25-gene signature specific to the Ras-EGFR ablation interaction and a distinct 19-gene EGFR ablation signature on normal keratinocytes. EGFR ablation in the context of wild-type Ras reduces ontologies favoring cell-cycle control and transcription, whereas oncogenic Ras enriches ontologies for ion channels and membrane transporters, particularly focused on calcium homeostasis. Ontologies between chronic EGFR ablation and acute pharmacologic ablation were unique, both with and without Ras activation. p38α is activated in response to abrogation of EGFR signaling under conditions of Ras activation in both mouse and human keratinocytes and in RAS-transformed tumor orthografts of EGFR-ablated mouse keratinocytes. EGFR ablation in the absence of oncogenic Ras revealed Erk and interleukin-1β-related pathways. CONCLUSION These findings reveal unrecognized interactions between Ras and EGFR signaling in squamous tumor cells that could influence the therapeutic response to EGFR ablation therapy.
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Affiliation(s)
- Lisa Nolan Wright
- Laboratory of Cancer Biology and Genetics, Center for Cancer Research, National Cancer Institute, Bethesda, Maryland 20892, USA
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Interaction of plasma membrane Ca(2+)-ATPase isoform 4 with calcineurin A: implications for catecholamine secretion by PC12 cells. Biochem Biophys Res Commun 2011; 411:235-40. [PMID: 21740891 DOI: 10.1016/j.bbrc.2011.06.098] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2011] [Accepted: 06/14/2011] [Indexed: 12/11/2022]
Abstract
PMCA1-4 isoforms have been recently recognised as regulators of various signalling pathways in mammalian cells. PMCAs were found to interact with calcineurin A in an isoform specific manner. In this study we focus on the interaction of calcineurin A with PMCA4 and its effect on catecholamine secretion in PC12 cells with reduced PMCA2 or PMCA3 content. Reduction of synthesis of PMCA2 or PMCA3 led to upregulation of PMCA4 manifested by preferential interaction of PMCA4 with calcineurin A. On the other hand, we observed a significant reduction of dopamine secretion, which did not correspond with an increased [Ca(2+)](c). This result indicates that the interaction of PMCA4 with calcineurin A plays a regulatory role in the signalling during catecholamine secretion.
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Ortuño-Sahagún D, Rivera-Cervantes MC, Gudiño-Cabrera G, Junyent F, Verdaguer E, Auladell C, Pallàs M, Camins A, Beas-Zárate C. Microarray analysis of rat hippocampus exposed to excitotoxicity: reversal Na(+)/Ca(2+) exchanger NCX3 is overexpressed in glial cells. Hippocampus 2010; 22:128-40. [PMID: 20928830 DOI: 10.1002/hipo.20869] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/02/2010] [Indexed: 02/06/2023]
Abstract
Multiple factors are involved in the glutamate-induced excitotoxicity phenomenon, such as overload of ionotropic and metabotropic receptors, excess Ca(2+) influx, nitric oxide synthase activation, oxidative damage due to increase in free radicals, and release of endogenous polyamine, among others. In order to attempt a more integrated approach to address this issue, we established, by microarray analysis, the hippocampus gene expression profiles under glutamate-induced excitotoxicity conditions. Increased gene expression is mainly related to excitotoxicity (CaMKII, glypican 2, GFAP, NCX3, IL-2, and Gmeb2) or with cell damage response (dynactin and Ecel1). Several genes that augmented their expression are related to glutamatergic system modulation, in particular with NMDA receptor modulation and calcium homeostasis (IL-2, CaMKII, acrosin, Gmeb2, hAChE, Slc83a, and SP1 factor). Conversely, among genes that diminished their expression, we found the Syngap 1, which is downregulated by CaMKII, and the MHC II, which is downregulated by glutamate. Changes observed in gene expression induced by monosodium glutamate (MSG) neonatal treatment in the hippocampus are consistent with the activation of the mechanisms that modulate NMDA receptor function as well as with the implementation of plastic response to cell damage and intracellular calcium homeostasis. Regarding this aspect, we report here that NCX3/Slc8a3, a Na(+)/Ca(2+) membrane exchanger, is highly expressed in astrocytes, both in vitro and in vivo, in response to glutamate-induced excitotoxicity. Hence, the results of this analysis present a broad view of the expression profile elicited by MSG neonatal treatment, and lead us to suggest the possible molecular pathways of action and reaction involved under this experimental model of excitotoxicity.
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Affiliation(s)
- Daniel Ortuño-Sahagún
- Laboratorio de Desarrollo y Regeneración Neural, Instituto de Neurobiología, C.U.C.B.A, Universidad de Guadalajara, Guadalajara, Jalisco, México
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18
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Brini M, Di Leva F, Ortega CK, Domi T, Ottolini D, Leonardi E, Tosatto SCE, Carafoli E. Deletions and mutations in the acidic lipid-binding region of the plasma membrane Ca2+ pump: a study on different splicing variants of isoform 2. J Biol Chem 2010; 285:30779-91. [PMID: 20643655 DOI: 10.1074/jbc.m110.140475] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Acidic phospholipids increase the affinity of the plasma membrane Ca(2+)-ATPase pump for Ca(2+). They interact with the C-terminal region of the pump and with a domain in the loop connecting transmembrane domains 2 and 3 (A(L) region) next to site A of alternative splicing. The contribution of the two phospholipid-binding sites and the possible interference of splicing inserts at site A with the regulation of the ATPase activity of isoform 2 of the pump by phospholipids have been analyzed. The activity of the full-length z/b variant (no insert at site A), the w/b (with insert at site A), and the w/a variant, containing both the 45-amino acid A-site insert and a C-site insert that truncates the pump in the calmodulin binding domain, has been analyzed in microsomal membranes of overexpressing CHO cells. The A-site insertion did not modify the phospholipid sensitivity of the pump, but the doubly inserted w/a variant became insensitive to acidic phospholipids, even if containing the intact A(L) phospholipid binding domain. Pump mutants in which 12 amino acids had been deleted, or single lysine mutations introduced, in the A(L) region were studied by monitoring agonist-induced Ca(2+) transients in overexpressing CHO cells. The 12-residue deletion completely abolished the ATPase activity of the w/a variant but only reduced that of the z/b variant, which was also affected by the single lysine substitutions in the same domain. A structural interpretation of the interplay of the pump with phospholipids, and of the mechanism of their activation, is proposed on the basis of molecular modeling studies.
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Affiliation(s)
- Marisa Brini
- Department of Biological Chemistry, University of Padova, 35131 Padova, Italy.
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19
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Zhang WB, Kwan CY. Unrepeatable extracellular Ca2+-dependent contractile effects of cyclopiazonic acid in rat vascular smooth muscle. Eur J Pharmacol 2009; 610:81-6. [PMID: 19292983 DOI: 10.1016/j.ejphar.2009.03.030] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2009] [Accepted: 03/09/2009] [Indexed: 11/16/2022]
Abstract
Cyclopiazonic acid (CPA), a specific reversible inhibitor of Ca(2+)-pumps in sarcoplasmic reticulum, causes a slowly developing and subsequently diminishing characteristic contraction in endothelium-denuded rat vascular smooth muscle. We recently found that CPA-induced contractions were not completely repeatable in endothelium-denuded rat aorta and superior mesenteric artery. 10 microM CPA-induced contractions expressed as a percentage of 80 mM KCl-induced contraction were significantly decreased from 51.4+/-5.7% to 11.8+/-2.6% (P<0.0001) upon the second application in endothelium-denuded rat aorta, and this was not due to any irreversible cytotoxic effects of CPA. The decrease of CPA-induced contractile responses upon the second application was dependent on both types of blood vessels and doses of CPA upon the first application. CPA upon the second application in Ca(2+)-containing solutions did induce its characteristic contractions in the rings pretreated with Ca(2+)-free solutions or Ca(2+) entry blockers before and during its first application, suggesting that capacitative mode of Ca(2+) influx during the application of CPA might be responsible for the diminishment of contractions upon the second application. These data suggest that CPA by inducing a transient rise in cytosolic Ca(2+) level might cause a long-lasting upregulation of Ca(2+) extrusion across the plasma membrane in vascular smooth muscle cells and thus accelerate Ca(2+) efflux over a prolonged period, leading to unrepeatable contractile effects of CPA. Such long-lasting upregulation of Ca(2+) extrusion may contribute to the regulation of excitability of vascular smooth muscle cells and protect the cells against excitotoxic injury.
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Affiliation(s)
- Wen-Bo Zhang
- Research Institute of Basic Medical Sciences and Vascular Biology Research Group, College of Medicine, China Medical University, 91 Hue-Shih Road, Taichung, 40402, Taiwan
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20
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Burette AC, Strehler EE, Weinberg RJ. "Fast" plasma membrane calcium pump PMCA2a concentrates in GABAergic terminals in the adult rat brain. J Comp Neurol 2009; 512:500-13. [PMID: 19025983 DOI: 10.1002/cne.21909] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The plasma membrane Ca(2+)-ATPases (PMCA) represent the major high-affinity Ca(2+) extrusion system in the brain. PMCAs comprise four isoforms and over 20 splice variants. Their different functional properties may permit different PMCA splice variants to accommodate different kinds of local [Ca(2+)] transients, but for a specific PMCA to play a unique role in local Ca(2+) handling it must be targeted to the appropriate subcellular compartment. We used immunohistochemistry to study the spatial distribution of PMCA2a-one of the two major carboxyl-terminal splice variants of PMCA2-in the adult rat brain, testing whether this isoform, with especially high basal activity, is targeted to specific subcellular compartments. In striking contrast to the widespread distribution of PMCA2 as a whole, we found that PMCA2a is largely restricted to parvalbumin-positive inhibitory presynaptic terminals throughout the brain. The only major exception to this targeting pattern was in the cerebellar cortex, where PMCA2a also concentrates postsynaptically, in the spines of Purkinje cells. We propose that the fast Ca(2+) activation kinetics and high V(max) of PMCA2a make this pump especially suited for rapid clearance of presynaptic Ca(2+) in fast-spiking inhibitory nerve terminals, which face severe transient calcium loads.
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Affiliation(s)
- Alain C Burette
- Department of Cell and Developmental Biology, University of North Carolina, Chapel Hill, North Carolina 27599, USA.
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Boursiac Y, Harper JF. The origin and function of calmodulin regulated Ca2+ pumps in plants. J Bioenerg Biomembr 2008; 39:409-14. [PMID: 18000746 DOI: 10.1007/s10863-007-9104-z] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
While Ca2+ signaling plays an important role in both plants and animals, the machinery that codes and decodes these signals have evolved to show interesting differences and similarities. For example, typical plant and animal cells both utilize calmodulin (CaM)-regulated Ca2+ pumps at the plasma membrane to help control cytoplasmic Ca2+ levels. However, in flowering plants this family of pumps has evolved with a unique structural arrangement in which the regulatory domain is located at the N-terminal instead of C-terminal end. In addition, some of the plant isoforms have evolved to function at endomembrane locations. For the 14 Ca2+ pumps present in the model plant Arabidopsis, molecular genetic analyses are providing exciting insights into their function in diverse aspects of plant growth and development.
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Affiliation(s)
- Yann Boursiac
- Biochemistry Department MS200, Fleischmann Agriculture Building, University of Nevada, Reno, NV 89557, USA
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22
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Di Leva F, Domi T, Fedrizzi L, Lim D, Carafoli E. The plasma membrane Ca2+ ATPase of animal cells: structure, function and regulation. Arch Biochem Biophys 2008; 476:65-74. [PMID: 18328800 DOI: 10.1016/j.abb.2008.02.026] [Citation(s) in RCA: 192] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2008] [Revised: 02/15/2008] [Accepted: 02/17/2008] [Indexed: 12/19/2022]
Abstract
Most important processes in cell life are regulated by calcium (Ca2+). A number of mechanisms have thus been developed to maintain the concentration of free Ca2+ inside cells at the level (100-200nM) necessary for the optimal operation of the targets of its regulatory function. The systems that move Ca2+ back and forth across membranes are important actors in its control. The plasma membrane calcium ATPase (PMCA pump) which ejects Ca2+ from all eukaryotic cell types will be the topic of this contribution. The pump uses a molecule of ATP to transport one molecule of Ca2+ from the cytosol to the external environment. It is a P-type ATPase encoded by four genes (ATP2B1-4), the transcripts of which undergo different types of alternative splicing. Many pump variants thus exist. Their multiplicity is best explained by the specific Ca2+ demands in different cell types. In keeping with these demands, the isoforms are differently expressed in tissues and cell types and have differential Ca2+ extruding properties. At very low Ca2+ concentrations the PMCAs are nearly inactive. They must be activated by calmodulin, by acid phospholipids, by protein kinases, and by other means, e.g., a dimerization process. Other proteins interact with the PMCAs (i.e., MAGUK and NHERF at the PDZ domain and calcineurin A in the main intracellular domain) to sort them to specific regions of the cell membrane or to regulate their function. In some cases the interaction is isoform, or even splice variant specific. PMCAs knock out (KO) mice have been generated and have contributed information on the importance of PMCAs to cells and organisms. So far, only one human genetic disease, hearing loss, has been traced back to a PMCA defect.
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Affiliation(s)
- Francesca Di Leva
- Department of Biochemistry, University of Padova, Viale G. Colombo, 3 35131 Padova, Italy
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Abstract
In mammals, four different genes encode four PMCA (plasma-membrane Ca(2+)-ATPase) isoforms. PMCA1 and 4 are expressed ubiquitously, and PMCA2 and 3 are expressed predominantly in the central nervous system. More than 30 variants are generated by mechanisms of alternative splicing. The physiological meaning of the existence of so many isoforms is not clear, but evidently it must be related to the cell-specific demands of Ca(2+) homoeostasis. Recent studies suggest that the alternatively spliced regions in PMCA are responsible for specific targeting to plasma membrane domains, and proteins that bind specifically to the pumps could contribute to further regulation of Ca(2+) control. In addition, the combination of proteins obtained by alternative splicing occurring at two different sites could be responsible for different functional characteristics of the pumps.
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Szewczyk MM, Pande J, Grover AK. Caloxins: a novel class of selective plasma membrane Ca2+ pump inhibitors obtained using biotechnology. Pflugers Arch 2007; 456:255-66. [PMID: 17909851 DOI: 10.1007/s00424-007-0348-6] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2007] [Accepted: 09/06/2007] [Indexed: 12/22/2022]
Abstract
Plasma membrane Ca2+ pumps (PMCA) extrude cellular Ca2+ with a high affinity and hence play a major role in Ca2+ homeostasis and signaling. Caloxins (selective extracellular PMCA inhibitors) would aid in elucidating the physiology of PMCA. PMCA proteins have five extracellular domains (exdoms). Our hypotheses are: 1) peptides that bind selectively to each exdom can be invented by screening a random peptide library, and 2) a peptide can modulate PMCA activity by binding to one of the exdoms. The first caloxin 2a1, selected for binding exdom 2 was selective for PMCA (Ki=529 microM). It has been used to examine the physiological role of PMCA. PMCA isoforms are encoded by four genes. PMCA isoform expression differs in various cell types, with PMCA1 and 4 being the most widely distributed. There are differences between PMCA1-4 exdom 1 sequences, which may be exploited for inventing isoform selective caloxins. Using exdom 1 of PMCA4 as a target, modified screening procedures and mutagenesis led to the high-affinity caloxin 1c2 (Ki=2.3 microM for PMCA4). It is selective for PMCA4 over PMCA1, 2, or 3. We hope that caloxins can be used to discern the roles of individual PMCA isoforms in Ca2+ homeostasis and signaling. Caloxins may also become clinically useful in cardiovascular diseases, neurological disorders, retinopathy, cancer, and contraception.
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Affiliation(s)
- Magdalena M Szewczyk
- Department of Biology, McMaster University, HSC 4N41, 1200 Main Street W, Hamilton, ON L8N3Z5, Canada
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Talarico EF, Mangini NJ. Alternative splice variants of plasma membrane calcium-ATPases in human corneal epithelium. Exp Eye Res 2007; 85:869-79. [PMID: 17931625 DOI: 10.1016/j.exer.2007.08.023] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2007] [Revised: 08/27/2007] [Accepted: 08/28/2007] [Indexed: 10/22/2022]
Abstract
Plasma membrane calcium-ATPases (PMCAs) play a critical role in regulating intracellular calcium concentration. Four genes encode PMCA proteins with alternative splicing of transcripts at three sites (A, B and C) serving to increase isoform diversity. Our previous work shows that all four PMCAs are expressed and have specific locations in human corneal epithelium (hCE). The present work examined which splice variants of PMCAs are expressed in hCE. Total RNA was extracted from hCE scraped from cadaver corneas of five different donors (two females and three males, age range 55-76 years). RT-PCR was performed using PMCA isoform-specific primers designed to amplify transcripts that included either splice site A or splice sites B and C. PMCA cDNAs were sequenced or cloned, and then sequenced. There was uniformity in the PMCA1 and PMCA4 expression profile among the five donors. Specifically, every donor expressed PMCA4 transcripts (4x at site A and 4b at site B/C). Every donor also expressed PMCA1 transcripts at sites B/C, specifically PMCA1b and PMCA1kb. In contrast, PMCA2 and PMCA3 expression varied; PCR DNAs were detected in two of five donors. One donor expressed PMCA2a and a novel PMCA2 variant we termed PMCA2((i)). PMCA3a transcript was demonstrated in a different donor. Finally, for all the donors, bands encoding site A transcripts for PMCA4 were obtained but no PCR transcripts were detected at site A for PMCA1, PMCA2 and PMCA3. This investigation showed that hCE expressed multiple splice variants of PMCA isoforms. Furthermore, this study documented the expression of the PMCA1k variant (PMCA1kb) previously only described in intestine and pancreatic beta cells and describes a novel PMCA2((i)) variant. Finally, this study suggests that the molecular configuration of PMCA1, PMCA2 and PMCA3 in the region of splice site A in hCE must be different than in other tissues since the same primers that produced site A transcripts in several other tissues were ineffective in priming PCR in hCE.
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Affiliation(s)
- Ernest F Talarico
- Department of Anatomy and Cell Biology, Indiana University School of Medicine-Northwest, Gary, IN 46408-1197, USA.
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