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Jardin I, Berna-Erro A, Nieto-Felipe J, Macias A, Sanchez-Collado J, Lopez JJ, Salido GM, Rosado JA. Similarities and Differences between the Orai1 Variants: Orai1α and Orai1β. Int J Mol Sci 2022; 23:ijms232314568. [PMID: 36498894 PMCID: PMC9735889 DOI: 10.3390/ijms232314568] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2022] [Revised: 11/16/2022] [Accepted: 11/21/2022] [Indexed: 11/24/2022] Open
Abstract
Orai1, the first identified member of the Orai protein family, is ubiquitously expressed in the animal kingdom. Orai1 was initially characterized as the channel responsible for the store-operated calcium entry (SOCE), a major mechanism that allows cytosolic calcium concentration increments upon receptor-mediated IP3 generation, which results in intracellular Ca2+ store depletion. Furthermore, current evidence supports that abnormal Orai1 expression or function underlies several disorders. Orai1 is, together with STIM1, the key element of SOCE, conducting the Ca2+ release-activated Ca2+ (CRAC) current and, in association with TRPC1, the store-operated Ca2+ (SOC) current. Additionally, Orai1 is involved in non-capacitative pathways, as the arachidonate-regulated or LTC4-regulated Ca2+ channel (ARC/LRC), store-independent Ca2+ influx activated by the secretory pathway Ca2+-ATPase (SPCA2) and the small conductance Ca2+-activated K+ channel 3 (SK3). Furthermore, Orai1 possesses two variants, Orai1α and Orai1β, the latter lacking 63 amino acids in the N-terminus as compared to the full-length Orai1α form, which confers distinct features to each variant. Here, we review the current knowledge about the differences between Orai1α and Orai1β, the implications of the Ca2+ signals triggered by each variant, and their downstream modulatory effect within the cell.
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Lisek M, Mackiewicz J, Sobolczyk M, Ferenc B, Guo F, Zylinska L, Boczek T. Early Developmental PMCA2b Expression Protects From Ketamine-Induced Apoptosis and GABA Impairments in Differentiating Hippocampal Progenitor Cells. Front Cell Neurosci 2022; 16:890827. [PMID: 35677757 PMCID: PMC9167922 DOI: 10.3389/fncel.2022.890827] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2022] [Accepted: 04/26/2022] [Indexed: 11/30/2022] Open
Abstract
PMCA2 is not expressed until the late embryonic state when the control of subtle Ca2+ fluxes becomes important for neuronal specialization. During this period, immature neurons are especially vulnerable to degenerative insults induced by the N-methyl-D-aspartate (NMDA) receptor blocker, ketamine. As H19-7 hippocampal progenitor cells isolated from E17 do not express the PMCA2 isoform, they constitute a valuable model for studying its role in neuronal development. In this study, we demonstrated that heterologous expression of PMCA2b enhanced the differentiation of H19-7 cells and protected from ketamine-induced death. PMCA2b did not affect resting [Ca2+]c in the presence or absence of ketamine and had no effect on the rate of Ca2+ clearance following membrane depolarization in the presence of the drug. The upregulation of endogenous PMCA1 demonstrated in response to PMCA2b expression as well as ketamine-induced PMCA4 depletion were indifferent to the rate of Ca2+ clearance in the presence of ketamine. Yet, co-expression of PMCA4b and PMCA2b was able to partially restore Ca2+ extrusion diminished by ketamine. The profiling of NMDA receptor expression showed upregulation of the NMDAR1 subunit in PMCA2b-expressing cells and increased co-immunoprecipitation of both proteins following ketamine treatment. Further microarray screening demonstrated a significant influence of PMCA2b on GABA signaling in differentiating progenitor cells, manifested by the unique regulation of several genes key to the GABAergic transmission. The overall activity of glutamate decarboxylase remained unchanged, but Ca2+-induced GABA release was inhibited in the presence of ketamine. Interestingly, PMCA2b expression was able to reverse this effect. The mechanism of GABA secretion normalization in the presence of ketamine may involve PMCA2b-mediated inhibition of GABA transaminase, thus shifting GABA utilization from energetic purposes to neurosecretion. In this study, we show for the first time that developmentally controlled PMCA expression may dictate the pattern of differentiation of hippocampal progenitor cells. Moreover, the appearance of PMCA2 early in development has long-standing consequences for GABA metabolism with yet an unpredictable influence on GABAergic neurotransmission during later stages of brain maturation. In contrast, the presence of PMCA2b seems to be protective for differentiating progenitor cells from ketamine-induced apoptotic death.
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Affiliation(s)
- Malwina Lisek
- Department of Molecular Neurochemistry, Medical University of Lodz, Łódz, Poland
| | - Joanna Mackiewicz
- Department of Molecular Neurochemistry, Medical University of Lodz, Łódz, Poland
| | - Marta Sobolczyk
- Department of Molecular Neurochemistry, Medical University of Lodz, Łódz, Poland
| | - Bozena Ferenc
- Department of Molecular Neurochemistry, Medical University of Lodz, Łódz, Poland
| | - Feng Guo
- Department of Pharmaceutical Toxicology, China Medical University, Shenyang, China
| | - Ludmila Zylinska
- Department of Molecular Neurochemistry, Medical University of Lodz, Łódz, Poland
| | - Tomasz Boczek
- Department of Molecular Neurochemistry, Medical University of Lodz, Łódz, Poland
- *Correspondence: Tomasz Boczek
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Zaidi A, Adewale M, McLean L, Ramlow P. The plasma membrane calcium pumps-The old and the new. Neurosci Lett 2019; 663:12-17. [PMID: 29452610 DOI: 10.1016/j.neulet.2017.09.066] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2017] [Revised: 09/29/2017] [Accepted: 09/30/2017] [Indexed: 12/27/2022]
Abstract
The plasma membrane Ca2+-ATPase (PMCA) pumps play a critical role in the maintenance of calcium (Ca2+) homeostasis, crucial for optimal neuronal function and cell survival. Loss of Ca2+ homeostasis is a key precursor in neuronal dysfunction associated with brain aging and in the pathogenesis of neurodegenerative disorders. In this article, we review evidence showing age-related changes in the PMCAs in synaptic plasma membranes (SPMs) and lipid raft microdomains isolated from rat brain. Both PMCA activity and protein levels decline progressively with increasing age. However, the loss of activity is disproportionate to the reduction of protein levels suggesting the presence of dysfunctional PMCA molecules in aged brain. PMCA activity is also diminished in post-mortem human brain samples from Alzheimer's disease and Parkinson's disease patients and in cell models of these neurodegenerative disorders. Experimental reduction of the PMCAs not only alter Ca2+ homeostasis but also have diverse effects on neurons such as reduced neuritic network, impaired release of neurotransmitter and increased susceptibility to stressful stimuli, particularly to agents that elevate intracellular Ca2+ [Ca2+]i. Loss of PMCA is likely to contribute to neuronal dysfunction observed in the aging brain and in the development of age-dependent neurodegenerative disorders. Therapeutic (pharmacological and/or non-pharmacological) approaches that can enhance PMCA activity and stabilize [Ca2+]i homeostasis may be capable of preventing, slowing, and/or reversing neuronal degeneration.
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Affiliation(s)
- Asma Zaidi
- Division of Basic Sciences, Kansas City University of Medicine and Biosciences, 1750 Independence Avenue, Kansas City, MO 64106, USA.
| | - Mercy Adewale
- Division of Basic Sciences, Kansas City University of Medicine and Biosciences, 1750 Independence Avenue, Kansas City, MO 64106, USA
| | - Lauren McLean
- Division of Basic Sciences, Kansas City University of Medicine and Biosciences, 1750 Independence Avenue, Kansas City, MO 64106, USA
| | - Paul Ramlow
- Division of Basic Sciences, Kansas City University of Medicine and Biosciences, 1750 Independence Avenue, Kansas City, MO 64106, USA
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4
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Wang G, Fang X, Han M, Wang X, Huang Q. MicroRNA-493-5p promotes apoptosis and suppresses proliferation and invasion in liver cancer cells by targeting VAMP2. Int J Mol Med 2018; 41:1740-1748. [PMID: 29328362 DOI: 10.3892/ijmm.2018.3358] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2016] [Accepted: 12/15/2017] [Indexed: 11/05/2022] Open
Abstract
The aim of the present study was to explore the role of miR‑493-5p in liver cancer tissues and cell lines, and its effect on cell behavioral characteristics. The expression of miR-493-5p was detected by reverse transcription-quantitative polymerase chain reaction (RT-qPCR) in liver cancer tissues and cell lines (hepatic cell line HL-7702 and the liver cancer cell lines HCCC-9810, HuH-7 and HepG2). In addition, the mechanism by which miR-493-5p mediates its effects was analyzed via the transfection of miR-493-5p mimic and negative control miRNA into HepG2 cells. The viability, proliferation, apoptosis and invasion of the cells were analyzed using MTT assay, flow cytometry and Transwell chamber experiments. Furthermore, the effect of miR-493-5p on the expression of vesicle associated membrane protein 2 (VAMP2) was assayed using a dual-luciferase reporter system, and VAMP2 protein levels were determined by western blot analysis. In addition, following the cotransfection of HepG2 cells with pcDNA3.1‑VAMP2 plasmid and miR‑493-5p mimic, the role of miR-493-5p as a regulator of VAMP2 was evaluated using MTT assay, flow cytometry and Transwell chamber experiments. RT-qPCR analysis indicated that the expression of miR-493-5p in liver cancer tissues and cell lines was decreased significantly compared with that in adjacent normal liver tissues and normal liver cell lines, respectively. Compared with the control group, the cells transfected with miR-493-5p mimic (the miR-493-5p overexpression group) exhibited reduced cell viability, a reduced percentage of cells in the S phase and an increased percentage of apoptotic cells. In addition, fewer cells passed through the Transwell membrane in the miR-493-5p overexpression group compared with the control group. In the dual-luciferase reporter assay, luciferase activity in the miR‑493-5p overexpression group was attenuated compared with that in the control group. In addition, western blot analysis indicated that the VAMP2 protein levels in the miR‑493-5p overexpression group were lower than those in the control group. Furthermore, in cells overexpressing miR-493-5p and VAMP2 simultaneously, the biological behavior of the cells, including cell viability, cell cycle and cell invasiveness, was significantly rescued compared with that of the control group transfected with miR‑493-5p alone. In conclusion, miR-493-5p is indicated to be a tumor suppressor gene, and is downregulated in human liver cancer. miR-493-5p overexpression promotes cell apoptosis and inhibits the proliferation and migration of liver cancer cells by negatively regulating the expression of VAMP. These observations suggest the potential of treating liver cancer by the overexpression of microRNA-493-5p.
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Affiliation(s)
- Guannan Wang
- Department of Pancreato-Biliary Surgery, Anhui Provincial Hospital Affiliated to Anhui Medical University, Hefei, Anhui 230001, P.R. China
| | - Xiaosan Fang
- Department of Hepatobiliary Surgery, Yijishan Hospital Affiliated to Wannan Medical College, Wuhu, Anhui 241001, P.R. China
| | - Meng Han
- Department of Hepatobiliary Surgery, Yijishan Hospital Affiliated to Wannan Medical College, Wuhu, Anhui 241001, P.R. China
| | - Xiaoming Wang
- Department of Hepatobiliary Surgery, Yijishan Hospital Affiliated to Wannan Medical College, Wuhu, Anhui 241001, P.R. China
| | - Qiang Huang
- Department of Pancreato-Biliary Surgery, Anhui Provincial Hospital Affiliated to Anhui Medical University, Hefei, Anhui 230001, P.R. China
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Banks DA, Dahal A, McFarland AG, Flowers BM, Stephens CA, Swack B, Gugssa A, Anderson WA, Hinton SD. MK-STYX Alters the Morphology of Primary Neurons, and Outgrowths in MK-STYX Overexpressing PC-12 Cells Develop a Neuronal Phenotype. Front Mol Biosci 2017; 4:76. [PMID: 29250526 PMCID: PMC5715325 DOI: 10.3389/fmolb.2017.00076] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2017] [Accepted: 11/02/2017] [Indexed: 01/14/2023] Open
Abstract
We previously reported that the pseudophosphatase MK-STYX (mitogen activated kinase phosphoserine/threonine/tyrosine binding protein) dramatically increases the number of what appeared to be primary neurites in rat pheochromocytoma (PC-12) cells; however, the question remained whether these MK-STYX-induced outgrowths were bona fide neurites, and formed synapses. Here, we report that microtubules and microfilaments, components of the cytoskeleton that are involved in the formation of neurites, are present in MK-STYX-induced outgrowths. In addition, in response to nerve growth factor (NGF), MK-STYX-expressing cells produced more growth cones than non-MK-STYX-expressing cells, further supporting a model in which MK-STYX has a role in actin signaling. Furthermore, immunoblot analysis demonstrates that MK-STYX modulates actin expression. Transmission electron microscopy confirmed that MK-STYX-induced neurites form synapses. To determine whether these MK-STYX-induced neurites have pre-synaptic or post-synaptic properties, we used classical markers for axons and dendrites, Tau-1 and MAP2 (microtubule associated protein 2), respectively. MK-STYX induced neurites were dopaminergic and expression of both Tau-1 and MAP2 suggests that they have both axonal and dendritic properties. Further studies in rat hippocampal primary neurons demonstrated that MK-STYX altered their morphology. A significant number of primary neurons in the presence of MK-STYX had more than the normal number of primary neurites. Our data illustrate the novel findings that MK-STYX induces outgrowths in PC-12 cells that fit the criteria for neurites, have a greater number of growth cones, form synapses, and have pre-synaptic and post-synaptic properties. It also highlights that the pseudophosphatase MK-STYX significantly alters the morphology of primary neurons.
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Affiliation(s)
- Dallas A Banks
- Department of Biology, Integrated Science Center, College of William and Mary, Williamsburg, VA, United States
| | - Arya Dahal
- Department of Biology, Integrated Science Center, College of William and Mary, Williamsburg, VA, United States
| | - Alexander G McFarland
- Department of Biology, Integrated Science Center, College of William and Mary, Williamsburg, VA, United States
| | - Brittany M Flowers
- Department of Biology, Integrated Science Center, College of William and Mary, Williamsburg, VA, United States.,National Cancer Institute, National Institutes of Health, Bethesda, MD, United States
| | - Christina A Stephens
- Department of Chemistry, Integrated Science Center, College of William and Mary, Williamsburg, VA, United States
| | - Benjamin Swack
- Department of Biology, Integrated Science Center, College of William and Mary, Williamsburg, VA, United States
| | - Ayele Gugssa
- Department of Biology, Howard University, Washington, DC, United States
| | | | - Shantá D Hinton
- Department of Biology, Integrated Science Center, College of William and Mary, Williamsburg, VA, United States
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Boczek T, Lisek M, Ferenc B, Zylinska L. Cross talk among PMCA, calcineurin and NFAT transcription factors in control of calmodulin gene expression in differentiating PC12 cells. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2017; 1860:502-515. [PMID: 28153703 DOI: 10.1016/j.bbagrm.2017.01.012] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/17/2016] [Revised: 01/16/2017] [Accepted: 01/27/2017] [Indexed: 11/19/2022]
Abstract
Brain aging is characterized by progressive loss of plasma membrane calcium pump (PMCA) and its activator - calmodulin (CaM), but the mechanism of this phenomenon remains unresolved. CaM encoded by three genes Calm1, Calm2, Calm3, works to translate Ca2+ signal into changes in frequently opposite cellular activities. This unique function allows CaM to affect gene expression via stimulation of calcineurin (CaN) and its downstream target - nuclear factor of activated T-cells (NFAT) and to terminate Ca2+ signal by stimulation of its extrusion. PMCA, which exists in four isoforms PMCA1-4, may in turn shape the pattern of Ca2+ transients and control CaN activity by its direct binding. Therefore, the interplay between PMCA, CaM and CaN/NFAT is highly plausible. To verify that, we used differentiated PC12 cells with reduced expression of PMCA2 or PMCA3 to mimic the potential changes in aged brain. Manipulation in PMCAs level decreased CaM protein in PMCA2 or PMCA3-reduced lines that was accompanied by down-regulation of Calm1 and Calm2 in both lines, but Calm3 only in PMCA2-reduced cells. Further studies showed substantially higher NFATc2 nuclear accumulation and increased NFAT transcriptional activity. Blocking of CaN/NFAT signalling resulted in almost full CaM recovery, mainly due to up-regulation of Calm2 and Calm3 genes. Moreover, higher occupancy of Calm2 and Calm3 promoters by NFATc2 and increased expression of these genes in response to NFATc2 silencing were demonstrated in PMCA2 and PMCA3-reduced lines. Our results indicate that decrease in CaM level in response to PMCAs downregulation can be driven by CaN/NFAT pathway.
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Affiliation(s)
- Tomasz Boczek
- Department of Molecular Neurochemistry, Medical University, Mazowiecka 6/8 Str., 92-215 Lodz, Poland; Boston Children's Hospital and Harvard Medical School, 300 Longwood Ave, Boston, MA 02115, USA.
| | - Malwina Lisek
- Department of Molecular Neurochemistry, Medical University, Mazowiecka 6/8 Str., 92-215 Lodz, Poland
| | - Bozena Ferenc
- Department of Molecular Neurochemistry, Medical University, Mazowiecka 6/8 Str., 92-215 Lodz, Poland
| | - Ludmila Zylinska
- Department of Molecular Neurochemistry, Medical University, Mazowiecka 6/8 Str., 92-215 Lodz, Poland
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Multifaceted plasma membrane Ca(2+) pumps: From structure to intracellular Ca(2+) handling and cancer. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2015; 1863:1351-63. [PMID: 26707182 DOI: 10.1016/j.bbamcr.2015.12.011] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/11/2015] [Revised: 11/25/2015] [Accepted: 12/12/2015] [Indexed: 11/20/2022]
Abstract
Plasma membrane Ca(2+) ATPases (PMCAs) are intimately involved in the control of intracellular Ca(2+) concentration. They reduce Ca(2+) in the cytosol not only by direct ejection, but also by controlling the formation of inositol-1,4,5-trisphosphate and decreasing Ca(2+) release from the endoplasmic reticulum Ca(2+) pool. In mammals four genes (PMCA1-4) are expressed, and alternative RNA splicing generates more than twenty variants. The variants differ in their regulatory characteristics. They localize into highly specialized membrane compartments and respond to the incoming Ca(2+) with distinct temporal resolution. The expression pattern of variants depends on cell type; a change in this pattern can result in perturbed Ca(2+) homeostasis and thus altered cell function. Indeed, PMCAs undergo remarkable changes in their expression pattern during tumorigenesis that might significantly contribute to the unbalanced Ca(2+) homeostasis of cancer cells. This article is part of a Special Issue entitled: Calcium and Cell Fate. Guest Editors: Jacques Haiech, Claus Heizmann, Joachim Krebs, Thierry Capiod and Olivier Mignen.
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Living without DAT: Loss and compensation of the dopamine transporter gene in sauropsids (birds and reptiles). Sci Rep 2015; 5:14093. [PMID: 26364979 PMCID: PMC4894405 DOI: 10.1038/srep14093] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2015] [Accepted: 08/18/2015] [Indexed: 11/17/2022] Open
Abstract
The dopamine transporter (DAT) is a major regulator of synaptic dopamine (DA) availability. It plays key roles in motor control and motor learning, memory formation, and reward-seeking behavior, is a major target of cocaine and methamphetamines, and has been assumed to be conserved among vertebrates. We have found, however, that birds, crocodiles, and lizards lack the DAT gene. We also found that the unprecedented loss of this important gene is compensated for by the expression of the noradrenaline transporter (NAT) gene, and not the serotonin transporter genes, in dopaminergic cells, which explains the peculiar pharmacology of the DA reuptake activity previously noted in bird striatum. This unexpected pattern contrasts with that of ancestral vertebrates (e.g. fish) and mammals, where the NAT gene is selectively expressed in noradrenergic cells. DA circuits in birds/reptiles and mammals thus operate with an analogous reuptake mechanism exerted by different genes, bringing new insights into gene expression regulation in dopaminergic cells and the evolution of a key molecular player in reward and addiction pathways.
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Regulation of GAP43/calmodulin complex formation via calcineurin-dependent mechanism in differentiated PC12 cells with altered PMCA isoforms composition. Mol Cell Biochem 2015; 407:251-62. [PMID: 26045175 PMCID: PMC4536269 DOI: 10.1007/s11010-015-2473-4] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2015] [Accepted: 05/30/2015] [Indexed: 12/21/2022]
Abstract
Several lines of evidence suggest the contribution of age-related decline in plasma membrane calcium pump (PMCA) to the onset of neurodegenerative diseases. From four PMCA isoforms, PMCA2, and PMCA3 respond to a rapid removal of Ca2+ and are expressed predominantly in excitable cells. We have previously shown that suppression of neuron-specific PMCAs in differentiated PC12 cells accelerated cell differentiation, but increased apoptosis in PMCA2-deficient line. We also demonstrated that altered expression of voltage-dependent calcium channels correlated with their higher contribution to Ca2+ influx, which varied between PMCA-reduced lines. Here, we propose a mechanism unique for differentiated PC12 cells by which PMCA2 and PMCA3 regulate pGAP43/GAP43 ratio and the interaction between GAP43 and calmodulin (CaM). Although down-regulation of PMCA2 or PMCA3 altered the content of GAP43/pGAP43, of paramount importance for the regulatory mechanism is a disruption of isoform-specific inhibitory PMCA/calcineurin interaction. In result, higher endogenous calcineurin (CaN) activity leads to hypophosphorylation of GAP43 in PMCA2- or PMCA3-deficient lines and intensification of GAP43/CaM complex formation, thus potentially limiting the availability of free CaM. In overall, our results indicate that both “fast” PMCA isoforms could actively regulate the local CaN function and CaN-downstream processes. In connection with our previous observations, we also suggest a negative feedback of cooperative action of CaM, GAP43, and CaN on P/Q and L-type channels activity. PMCAs- and CaN-dependent mechanism presented here, may signify a protective action against calcium overload in neuronal cells during aging, as well a potential way for decreasing neuronal cells vulnerability to neurodegenerative insults.
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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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