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Wasąg P, Suwińska A, Richert A, Lenartowska M, Lenartowski R. Plant-specific calreticulin is localized in the nuclei of highly specialized cells in the pistil-new observations for an old hypothesis. PROTOPLASMA 2024:10.1007/s00709-024-01961-y. [PMID: 38849663 DOI: 10.1007/s00709-024-01961-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/22/2023] [Accepted: 05/31/2024] [Indexed: 06/09/2024]
Abstract
One of the first cellular locations of the calreticulin (CRT) chaperone in eukaryotic cells, apart from its obvious localization in the endoplasmic reticulum (ER), was the cell nucleus (Opas et al. 1991). The presence of CRT has been detected inside the nucleus and in the nuclear envelope of animal and plant cells, and a putative nuclear localization signal (NLS) in the CRT amino acid sequence has been mapped in several animal and plant species. Over the last 30 years, other localization sites of this protein outside the ER and cell nucleus have also been discovered, suggesting that CRT is a multifunctional Ca2+-binding protein widely found in various cell types. In our previous studies focusing on plant developmental biology, we have demonstrated the presence of CRT inside and outside the ER in highly specialized plant cells, as well as the possibility of CRT localization in the cell nucleus. In this paper, we present a detailed analysis of immunocytochemical localization of CRT inside nuclei of the pistil transmission tract somatic cells before and after pollination. We show a similar pattern of the nuclear CRT localization in relation to exchangeable Ca2+ for two selected species of angiosperms, dicotyledonous Petunia and monocot Haemanthus, that differ in anatomical structure of the pistil and discuss the potential role of CRT in the cell nucleus.
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Affiliation(s)
- Piotr Wasąg
- Department of Cellular and Molecular Biology, Faculty of Biological and Veterinary Sciences, Nicolaus Copernicus University in Toruń, Toruń, Poland.
| | - Anna Suwińska
- Department of Cellular and Molecular Biology, Faculty of Biological and Veterinary Sciences, Nicolaus Copernicus University in Toruń, Toruń, Poland
- Centre for Modern Interdisciplinary Technologies, Nicolaus Copernicus University in Toruń, Toruń, Poland
| | - Anna Richert
- Department of Cellular and Molecular Biology, Faculty of Biological and Veterinary Sciences, Nicolaus Copernicus University in Toruń, Toruń, Poland
| | - Marta Lenartowska
- Department of Cellular and Molecular Biology, Faculty of Biological and Veterinary Sciences, Nicolaus Copernicus University in Toruń, Toruń, Poland
- Centre for Modern Interdisciplinary Technologies, Nicolaus Copernicus University in Toruń, Toruń, Poland
| | - Robert Lenartowski
- Department of Cellular and Molecular Biology, Faculty of Biological and Veterinary Sciences, Nicolaus Copernicus University in Toruń, Toruń, Poland
- Centre for Modern Interdisciplinary Technologies, Nicolaus Copernicus University in Toruń, Toruń, Poland
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2
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Carey RM, McMahon DB, Miller ZA, Kim T, Rajasekaran K, Gopallawa I, Newman JG, Basu D, Nead KT, White EA, Lee RJ. T2R bitter taste receptors regulate apoptosis and may be associated with survival in head and neck squamous cell carcinoma. Mol Oncol 2021; 16:1474-1492. [PMID: 34717036 PMCID: PMC8978516 DOI: 10.1002/1878-0261.13131] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2021] [Revised: 09/16/2021] [Accepted: 10/28/2021] [Indexed: 12/02/2022] Open
Abstract
Better management of head and neck squamous cell carcinomas (HNSCCs) requires a clearer understanding of tumor biology and disease risk. Bitter taste receptors (T2Rs) have been studied in several cancers, including thyroid, salivary, and GI, but their role in HNSCC has not been explored. We found that HNSCC patient samples and cell lines expressed functional T2Rs on both the cell and nuclear membranes. Bitter compounds, including bacterial metabolites, activated T2R‐mediated nuclear Ca2+ responses leading to mitochondrial depolarization, caspase activation, and ultimately apoptosis. Buffering nuclear Ca2+ elevation blocked caspase activation. Furthermore, increased expression of T2Rs in HNSCCs from The Cancer Genome Atlas is associated with improved overall survival. This work suggests that T2Rs are potential biomarkers to predict outcomes and guide treatment selection, may be leveraged as therapeutic targets to stimulate tumor apoptosis, and may mediate tumor‐microbiome crosstalk in HNSCC.
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Affiliation(s)
- Ryan M Carey
- Department of Otorhinolaryngology, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania, USA
| | - Derek B McMahon
- Department of Otorhinolaryngology, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania, USA
| | - Zoey A Miller
- Department of Otorhinolaryngology, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania, USA
| | - TaeBeom Kim
- Department of Epidemiology, Division of Cancer Prevention and Population Sciences, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA
| | - Karthik Rajasekaran
- Department of Otorhinolaryngology, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania, USA
| | - Indiwari Gopallawa
- Department of Otorhinolaryngology, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania, USA
| | - Jason G Newman
- Department of Otorhinolaryngology, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania, USA
| | - Devraj Basu
- Department of Otorhinolaryngology, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania, USA
| | - Kevin T Nead
- Department of Epidemiology, Division of Cancer Prevention and Population Sciences, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA.,Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA
| | - Elizabeth A White
- Department of Otorhinolaryngology, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania, USA
| | - Robert J Lee
- Department of Otorhinolaryngology, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania, USA.,Department of Physiology, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania, USA
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3
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The basis of nuclear phospholipase C in cell proliferation. Adv Biol Regul 2021; 82:100834. [PMID: 34710785 DOI: 10.1016/j.jbior.2021.100834] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Revised: 10/17/2021] [Accepted: 10/21/2021] [Indexed: 11/23/2022]
Abstract
Ca2+ is a highly versatile intracellular signal that regulates many biological processes such as cell death and proliferation. Broad Ca2+-signaling machinery is used to assemble signaling systems with a precise spatial and temporal resolution to achieve this versatility. Ca2+-signaling components can be organized in different regions of the cell and local increases in Ca2+ within the nucleus can regulate different cellular functions from the increases in cytosolic Ca2+. However, the mechanisms and pathways that promote localized increases in Ca2+ levels in the nucleus are still under investigation. This review presents evidence that the nucleus has its own Ca2+ stores and signaling machinery, which modulate processes such as cell proliferation and tumor growth. We focus on what is known about the functions of nuclear Phospholipase C (PLC) in the generation of nuclear Ca2+ transients that are involved in cell proliferation.
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4
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Studying Proton Gradients Across the Nuclear Envelope. Methods Mol Biol 2021; 2175:47-63. [PMID: 32681483 DOI: 10.1007/978-1-0716-0763-3_5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/10/2023]
Abstract
The existence of nuclear pore complexes in the nuclear envelope has led to the assumption that ions move freely from the cytosol into the nucleus, and that the molecular mechanisms at the plasma membrane that regulate cytosolic pH also regulate nuclear pH. Furthermore, studies to measure pH in the nucleus have produced contradictory results, since it has been found that the nuclear pH is either similar to the cytosol or more alkaline than the cytosol. However, most studies of nuclear pH have lacked the rigor needed to understand pH regulation in the nucleus. A major problem has been the lack of in situ titrations in the nucleus and cytosol, since the intracellular environment is different in the cytosol and nucleus and the behavior of fluorescent pH probes is different in these environments. Here we present a method that uses the fluorescence of SNARF-1 that labels both cytosol and nucleus. Using ratio imaging microscopy, regions of interest corresponding to the nucleus and cytosol to perform steady-state pH measurements followed by in situ titrations, to correctly assign pH in those cellular domains.
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5
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de Miranda MC, Rodrigues MA, de Angelis Campos AC, Faria JAQA, Kunrath-Lima M, Mignery GA, Schechtman D, Goes AM, Nathanson MH, Gomes DA. Epidermal growth factor (EGF) triggers nuclear calcium signaling through the intranuclear phospholipase Cδ-4 (PLCδ4). J Biol Chem 2019; 294:16650-16662. [PMID: 31537645 DOI: 10.1074/jbc.ra118.006961] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2018] [Revised: 09/10/2019] [Indexed: 02/06/2023] Open
Abstract
Calcium (Ca2+) signaling within the cell nucleus regulates specific cellular events such as gene transcription and cell proliferation. Nuclear and cytosolic Ca2+ levels can be independently regulated, and nuclear translocation of receptor tyrosine kinases (RTKs) is one way to locally activate signaling cascades within the nucleus. Nuclear RTKs, including the epidermal growth factor receptor (EGFR), are important for processes such as transcriptional regulation, DNA-damage repair, and cancer therapy resistance. RTKs can hydrolyze phosphatidylinositol 4,5-bisphosphate (PI(4,5)P2) within the nucleus, leading to Ca2+ release from the nucleoplasmic reticulum by inositol 1,4,5-trisphosphate receptors. PI(4,5)P2 hydrolysis is mediated by phospholipase C (PLC). However, it is unknown which nuclear PLC isoform is triggered by EGFR. Here, using subcellular fractionation, immunoblotting and fluorescence, siRNA-based gene knockdowns, and FRET-based biosensor reporter assays, we investigated the role of PLCδ4 in epidermal growth factor (EGF)-induced nuclear Ca2+ signaling and downstream events. We found that EGF-induced Ca2+ signals are inhibited when translocation of EGFR is impaired. Nuclear Ca2+ signals also were reduced by selectively buffering inositol 1,4,5-trisphosphate (InsP3) within the nucleus. EGF induced hydrolysis of nuclear PI(4,5)P2 by the intranuclear PLCδ4, rather than by PLCγ1. Moreover, protein kinase C, a downstream target of EGF, was active in the nucleus of stimulated cells. Furthermore, PLCδ4 and InsP3 modulated cell cycle progression by regulating the expression of cyclins A and B1. These results provide evidence that EGF-induced nuclear signaling is mediated by nuclear PLCδ4 and suggest new therapeutic targets to modulate the proliferative effects of this growth factor.
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Affiliation(s)
- Marcelo Coutinho de Miranda
- Department of Biochemistry and Immunology, Universidade Federal de Minas Gerais (UFMG), Av. Antonio Carlos, 6627 Belo Horizonte-MG, 31270-901, Brazil.,Section of Digestive Diseases, Internal Medicine, Yale University, New Haven, Connecticut 06520-8056
| | - Michele Angela Rodrigues
- Department of Biochemistry and Immunology, Universidade Federal de Minas Gerais (UFMG), Av. Antonio Carlos, 6627 Belo Horizonte-MG, 31270-901, Brazil.,Section of Digestive Diseases, Internal Medicine, Yale University, New Haven, Connecticut 06520-8056
| | - Ana Carolina de Angelis Campos
- Department of Biochemistry and Immunology, Universidade Federal de Minas Gerais (UFMG), Av. Antonio Carlos, 6627 Belo Horizonte-MG, 31270-901, Brazil.,Section of Digestive Diseases, Internal Medicine, Yale University, New Haven, Connecticut 06520-8056
| | | | - Marianna Kunrath-Lima
- Department of Biochemistry and Immunology, Universidade Federal de Minas Gerais (UFMG), Av. Antonio Carlos, 6627 Belo Horizonte-MG, 31270-901, Brazil
| | - Gregory A Mignery
- Department of Cell and Molecular Physiology, Stritch School of Medicine, Loyola University Chicago, Maywood, Illinois 60153
| | - Deborah Schechtman
- Department of Biochemistry, University of São Paulo, Av. Professor Lineu Prestes, 748, São Paulo-SP 05508-900, Brazil
| | - Alfredo Miranda Goes
- Department of Pathology, Universidade Federal de Minas Gerais (UFMG), Av. Antonio Carlos, 6627 Belo Horizonte-MG, 31270-901, Brazil
| | - Michael H Nathanson
- Section of Digestive Diseases, Internal Medicine, Yale University, New Haven, Connecticut 06520-8056
| | - Dawidson A Gomes
- Department of Biochemistry and Immunology, Universidade Federal de Minas Gerais (UFMG), Av. Antonio Carlos, 6627 Belo Horizonte-MG, 31270-901, Brazil .,Section of Digestive Diseases, Internal Medicine, Yale University, New Haven, Connecticut 06520-8056
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6
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Kunrath-Lima M, de Miranda MC, Ferreira ADF, Faraco CCF, de Melo MIA, Goes AM, Rodrigues MA, Faria JAQA, Gomes DA. Phospholipase C delta 4 (PLCδ4) is a nuclear protein involved in cell proliferation and senescence in mesenchymal stromal stem cells. Cell Signal 2018; 49:59-67. [PMID: 29859928 DOI: 10.1016/j.cellsig.2018.05.011] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2018] [Revised: 05/28/2018] [Accepted: 05/29/2018] [Indexed: 02/08/2023]
Abstract
Ca2+ is an important second messenger, and it is involved in many cellular processes such as cell death and proliferation. The rise in intracellular Ca2+ levels can be due to the generation of inositol 1,4,5-trisphosphate (InsP3), which is a product of phosphatidylinositol 4,5-bisphosphate (PIP2) hydrolysis by phospholipases C (PLCs), that leads to Ca2+ release from endoplasmic reticulum by InsP3 receptors (InsP3R). Ca2+ signaling patterns can vary in different regions of the cell and increases in nuclear Ca2+ levels have specific biological effects that differ from those of Ca2+ increase in the cytoplasm. There are PLCs in the cytoplasm and nucleus, but little is known about the functions of nuclear PLCs. This work aimed to characterize phenotypically the human PLCδ4 (hPLCδ4) in mesenchymal stem cells. This nuclear isoform of PLC is present in different cell types and has a possible role in proliferative processes. In this work, hPLCδ4 was found to be mainly nuclear in human adipose-derived mesenchymal stem cells (hASC). PLCδ4 knockdown demonstrated that it is essential for hASC proliferation, without inducing cell death. An increase of cells in G1, and a reduction of cells on interphase and G2/M in knockdown cells were seen. Furthermore, PLCδ4 knockdown increased the percentage of senescent cells, p16INK4A+ and p21Cip1 mRNAs expression, which could explain the impaired cell proliferation. The results show that hPLCδ4 is in involved in cellular proliferation and senescence in hASC.
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Affiliation(s)
- Marianna Kunrath-Lima
- Departamento de Bioquímica e Imunologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil
| | - Marcelo Coutinho de Miranda
- Departamento de Bioquímica e Imunologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil
| | - Andrea da Fonseca Ferreira
- Departamento de Bioquímica e Imunologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil
| | - Camila Cristina Fraga Faraco
- Departamento de Bioquímica e Imunologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil
| | - Mariane Izabella Abreu de Melo
- Departamento de Bioquímica e Imunologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil
| | - Alfredo Miranda Goes
- Departamento de Bioquímica e Imunologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil
| | - Michele Angela Rodrigues
- Departamento de Bioquímica e Imunologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil
| | | | - Dawidson Assis Gomes
- Departamento de Bioquímica e Imunologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil.
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7
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Santos JM, Martínez-Zaguilán R, Facanha AR, Hussain F, Sennoune SR. Vacuolar H+-ATPase in the nuclear membranes regulates nucleo-cytosolic proton gradients. Am J Physiol Cell Physiol 2016; 311:C547-C558. [PMID: 27510904 DOI: 10.1152/ajpcell.00019.2016] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2016] [Accepted: 06/26/2016] [Indexed: 01/01/2023]
Abstract
The regulation of the luminal pH of each organelle is crucial for its function and must be controlled tightly. Nevertheless, it has been assumed that the nuclear pH is regulated by the cytoplasmic proton transporters via the diffusion of H+ across the nuclear pores because of their large diameter. However, it has been demonstrated that ion gradients exist between cytosol and nucleus, suggesting that the permeability of ions across the nuclear pores is restricted. Vacuolar H+-ATPase (V-H+-ATPase) is responsible for the creation and maintenance of trans-membrane electrochemical gradient. We hypothesize that V-H+-ATPase located in the nuclear membranes functions as the primary mechanism to regulate nuclear pH and generate H+ gradients across the nuclear envelope. We studied the subcellular heterogeneity of H+ concentration in the nucleus and cytosol using ratio imaging microscopy and SNARF-1, a pH indicator, in prostate cells. Our results indicate that there are proton gradients across the nuclear membranes that are generated by V-H+-ATPase located in the outer and inner nuclear membranes. We demonstrated that these gradients are mostly dissipated by inhibiting V-H+-ATPase. Immunoblots and V-H+-ATPase activity corroborated the existence of V-H+-ATPase in the nuclear membranes. This study demonstrates that V-H+-ATPase is functionally expressed in nuclear membranes and is responsible for nuclear H+ gradients that may promote not only the coupled transport of substrates, but also most electrochemically driven events across the nuclear membranes. This study represents a paradigm shift that the nucleus can regulate its own pH microenvironment, providing new insights into nuclear ion homeostasis and signaling.
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Affiliation(s)
- Julianna Maria Santos
- Cell Physiology and Molecular Biophysics Department, Texas Tech University Health Sciences Center, Lubbock, Texas
| | - Raul Martínez-Zaguilán
- Cell Physiology and Molecular Biophysics Department, Texas Tech University Health Sciences Center, Lubbock, Texas
| | - Arnoldo Rocha Facanha
- Biosciences and Biotechnology Center, Cell Biology and Tissue Laboratory, Universidade Estadual do Norte Fluminense Darcy Ribeiro, Rio de Janeiro, Brazil; and
| | - Fazle Hussain
- Mechanical Engineering Department, Texas Tech University, Lubbock, Texas
| | - Souad R Sennoune
- Cell Physiology and Molecular Biophysics Department, Texas Tech University Health Sciences Center, Lubbock, Texas;
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8
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Chen F, Zhu L, Cai L, Zhang J, Zeng X, Li J, Su Y, Hu Q. A stromal interaction molecule 1 variant up-regulates matrix metalloproteinase-2 expression by strengthening nucleoplasmic Ca2+ signaling. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2016; 1863:617-29. [PMID: 26775216 DOI: 10.1016/j.bbamcr.2016.01.007] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/14/2015] [Revised: 01/02/2016] [Accepted: 01/11/2016] [Indexed: 10/22/2022]
Abstract
Very recent studies hold promise to reveal the role of stromal interaction molecule 1 (STIM1) in non-store-operated Ca2+ entry. Here we showed that in contrast to cytoplasmic membrane redistribution as previously noted, human umbilical vein endothelial STIM1 with a T-to-C nucleotide transition resulting in an amino acid substitution of leucine by proline in the signal peptide sequence translocated to perinuclear membrane upon intracellular Ca2+ depletion, amplified nucleoplasmic Ca2+ signaling through ryanodine receptor-dependent pathway, and enhanced the subsequent cAMP responsive element binding protein activity, matrix metalloproteinase-2 (MMP-2) gene expression, and endothelial tube forming. The abundance of mutated STIM1 and the MMP-2 expression were higher in native human umbilical vein endothelial cells of patients with gestational hypertension than controls and were significantly correlated with blood pressure. These findings broaden our understanding about structure-function bias of STIM1 and offer unique insights into its application in nucleoplasmic Ca2+, MMP-2 expression, endothelial dysfunction, and pathophysiological mechanism(s) of gestational hypertension.
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Affiliation(s)
- Fengrong Chen
- Department of Pathophysiology, School of Basic Medicine, Tongji Medical College, Huazhong Science and Technology University (HUST), Wuhan 430030, People's Republic of China; Key Laboratory of Pulmonary Diseases of Ministry of Health of China, Tongji Medical College, Huazhong Science and Technology University (HUST), Wuhan 430030, People's Republic of China
| | - Liping Zhu
- Department of Pathophysiology, School of Basic Medicine, Tongji Medical College, Huazhong Science and Technology University (HUST), Wuhan 430030, People's Republic of China; Key Laboratory of Pulmonary Diseases of Ministry of Health of China, Tongji Medical College, Huazhong Science and Technology University (HUST), Wuhan 430030, People's Republic of China
| | - Lei Cai
- Department of Pathophysiology, School of Basic Medicine, Tongji Medical College, Huazhong Science and Technology University (HUST), Wuhan 430030, People's Republic of China; Key Laboratory of Pulmonary Diseases of Ministry of Health of China, Tongji Medical College, Huazhong Science and Technology University (HUST), Wuhan 430030, People's Republic of China
| | - Jiwei Zhang
- Department of Pathophysiology, School of Basic Medicine, Tongji Medical College, Huazhong Science and Technology University (HUST), Wuhan 430030, People's Republic of China; Key Laboratory of Pulmonary Diseases of Ministry of Health of China, Tongji Medical College, Huazhong Science and Technology University (HUST), Wuhan 430030, People's Republic of China
| | - Xianqin Zeng
- Department of Pathophysiology, School of Basic Medicine, Tongji Medical College, Huazhong Science and Technology University (HUST), Wuhan 430030, People's Republic of China; Key Laboratory of Pulmonary Diseases of Ministry of Health of China, Tongji Medical College, Huazhong Science and Technology University (HUST), Wuhan 430030, People's Republic of China
| | - Jiansha Li
- Key Laboratory of Pulmonary Diseases of Ministry of Health of China, Tongji Medical College, Huazhong Science and Technology University (HUST), Wuhan 430030, People's Republic of China; Department of Pathology, Tongji Hospital, Tongji Medical College, Huazhong Science and Technology University (HUST), Wuhan 430030, People's Republic of China
| | - Yuan Su
- Key Laboratory of Pulmonary Diseases of Ministry of Health of China, Tongji Medical College, Huazhong Science and Technology University (HUST), Wuhan 430030, People's Republic of China; Department of Respiratory Medicine, Union Hospital, Tongji Medical College, Huazhong Science and Technology University (HUST), Wuhan 430030, People's Republic of China
| | - Qinghua Hu
- Department of Pathophysiology, School of Basic Medicine, Tongji Medical College, Huazhong Science and Technology University (HUST), Wuhan 430030, People's Republic of China; Key Laboratory of Pulmonary Diseases of Ministry of Health of China, Tongji Medical College, Huazhong Science and Technology University (HUST), Wuhan 430030, People's Republic of China; Key Laboratory of Molecular Biophysics of the Ministry of Education, Huazhong Science and Technology University (HUST), Wuhan 430030, People's Republic of China.
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9
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Oliveira AG, Guimarães ES, Andrade LM, Menezes GB, Fatima Leite M. Decoding calcium signaling across the nucleus. Physiology (Bethesda) 2015; 29:361-8. [PMID: 25180265 DOI: 10.1152/physiol.00056.2013] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Calcium (Ca(2+)) is an important multifaceted second messenger that regulates a wide range of cellular events. A Ca(2+)-signaling toolkit has been shown to exist in the nucleus and to be capable of generating and modulating nucleoplasmic Ca(2+) transients. Within the nucleus, Ca(2+) controls cellular events that are different from those modulated by cytosolic Ca(2+). This review focuses on nuclear Ca(2+) signals and their role in regulating physiological and pathological processes.
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Affiliation(s)
- André G Oliveira
- Department of Physiology and Biophysics, Federal University of Minas Gerais, Belo Horizonte, Brazil
| | - Erika S Guimarães
- Department of Physiology and Biophysics, Federal University of Minas Gerais, Belo Horizonte, Brazil; Molecular Medicine, School of Medicine, Federal University of Minas Gerais, Belo Horizonte, Brazil; and
| | - Lídia M Andrade
- Department of Physiology and Biophysics, Federal University of Minas Gerais, Belo Horizonte, Brazil
| | - Gustavo B Menezes
- Department of Morphology, Federal University of Minas Gerais, Belo Horizonte, Brazil
| | - M Fatima Leite
- Department of Physiology and Biophysics, Federal University of Minas Gerais, Belo Horizonte, Brazil;
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10
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Lenartowski R, Suwińska A, Lenartowska M. Calreticulin expression in relation to exchangeable Ca(2+) level that changes dynamically during anthesis, progamic phase, and double fertilization in Petunia. PLANTA 2015; 241:209-27. [PMID: 25262422 PMCID: PMC4282720 DOI: 10.1007/s00425-014-2178-z] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/18/2014] [Accepted: 09/15/2014] [Indexed: 05/25/2023]
Abstract
Calcium (Ca(2+)) plays essential roles in plant sexual reproduction, but the sites and the mechanism of Ca(2+) mobile storage during pollen-pistil interactions have not been fully defined. Because the Ca(2+)-buffering protein calreticulin (CRT) is able to bind and sequester Ca(2+), it can serve as a mobile intracellular store of easily releasable Ca(2+) and control its local concentration within the cytoplasm. Our previous studies showed an enhanced expression of Petunia hybrida CRT gene (PhCRT) during pistil transmitting tract maturation, pollen germination and tube outgrowth on the stigma, gamete fusion, and early embryogenesis. Here, we demonstrate that elevated expression of CRT results in the accumulation of this protein in response to anthesis, pollination, sperm cells deposition within the receptive synergid and fertilization, when the level of exchangeable Ca(2+) changes dynamically. CRT localizes mainly to the endoplasmic reticulum and Golgi compartments in the pistil transmitting tract cells, germinated pollen/tubes, and sporophytic/gametophytic cells of the ovule and corresponds with loosely bound Ca(2+). Additionally, the immunogold research shows, for the first time, highly selective CRT distribution in specific nuclear sub-domains. On the basis of our results, we discuss the possible functions of CRT with respect to the critical role of Ca(2+) homeostasis during key events of the multi-step process of generative reproduction in angiosperms.
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Affiliation(s)
- Robert Lenartowski
- Laboratory of Isotope and Instrumental Analysis, Faculty of Biology and Environment Protection, Nicolaus Copernicus University, Toruń, Poland,
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11
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López Sanjurjo CI, Tovey SC, Taylor CW. Rapid recycling of Ca2+ between IP3-sensitive stores and lysosomes. PLoS One 2014; 9:e111275. [PMID: 25337829 PMCID: PMC4206489 DOI: 10.1371/journal.pone.0111275] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2014] [Accepted: 09/28/2014] [Indexed: 11/26/2022] Open
Abstract
Inositol 1,4,5-trisphosphate (IP3) evokes release of Ca2+ from the endoplasmic reticulum (ER), but the resulting Ca2+ signals are shaped by interactions with additional intracellular organelles. Bafilomycin A1, which prevents lysosomal Ca2+ uptake by inhibiting H+ pumping into lysosomes, increased the amplitude of the initial Ca2+ signals evoked by carbachol in human embryonic kidney (HEK) cells. Carbachol alone and carbachol in combination with parathyroid hormone (PTH) evoke Ca2+ release from distinct IP3-sensitive Ca2+ stores in HEK cells stably expressing human type 1 PTH receptors. Bafilomycin A1 similarly exaggerated the Ca2+ signals evoked by carbachol or carbachol with PTH, indicating that Ca2+ released from distinct IP3-sensitive Ca2+ stores is sequestered by lysosomes. The Ca2+ signals resulting from store-operated Ca2+ entry, whether evoked by thapsigargin or carbachol, were unaffected by bafilomycin A1. Using Gd3+ (1 mM) to inhibit both Ca2+ entry and Ca2+ extrusion, HEK cells were repetitively stimulated with carbachol to assess the effectiveness of Ca2+ recycling to the ER after IP3-evoked Ca2+ release. Blocking lysosomal Ca2+ uptake with bafilomycin A1 increased the amplitude of each carbachol-evoked Ca2+ signal without affecting the rate of Ca2+ recycling to the ER. This suggests that Ca2+ accumulated by lysosomes is rapidly returned to the ER. We conclude that lysosomes rapidly, reversibly and selectively accumulate the Ca2+ released by IP3 receptors residing within distinct Ca2+ stores, but not the Ca2+ entering cells via receptor-regulated, store-operated Ca2+ entry pathways.
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Affiliation(s)
| | - Stephen C. Tovey
- Department of Pharmacology, University of Cambridge, Cambridge, United Kingdom
| | - Colin W. Taylor
- Department of Pharmacology, University of Cambridge, Cambridge, United Kingdom
- * E-mail:
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Ibarra C, Vicencio JM, Varas-Godoy M, Jaimovich E, Rothermel BA, Uhlén P, Hill JA, Lavandero S. An integrated mechanism of cardiomyocyte nuclear Ca(2+) signaling. J Mol Cell Cardiol 2014; 75:40-8. [PMID: 24997440 PMCID: PMC4626248 DOI: 10.1016/j.yjmcc.2014.06.015] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/30/2013] [Revised: 06/11/2014] [Accepted: 06/26/2014] [Indexed: 01/05/2023]
Abstract
In cardiomyocytes, Ca(2+) plays a central role in governing both contraction and signaling events that regulate gene expression. Current evidence indicates that discrimination between these two critical functions is achieved by segregating Ca(2+) within subcellular microdomains: transcription is regulated by Ca(2+) release within nuclear microdomains, and excitation-contraction coupling is regulated by cytosolic Ca(2+). Accordingly, a variety of agonists that control cardiomyocyte gene expression, such as endothelin-1, angiotensin-II or insulin-like growth factor-1, share the feature of triggering nuclear Ca(2+) signals. However, signaling pathways coupling surface receptor activation to nuclear Ca(2+) release, and the phenotypic responses to such signals, differ between agonists. According to earlier hypotheses, the selective control of nuclear Ca(2+) signals by activation of plasma membrane receptors relies on the strategic localization of inositol trisphosphate receptors at the nuclear envelope. There, they mediate Ca(2+) release from perinuclear Ca(2+) stores upon binding of inositol trisphosphate generated in the cytosol, which diffuses into the nucleus. More recently, identification of such receptors at nuclear membranes or perinuclear sarcolemmal invaginations has uncovered novel mechanisms whereby agonists control nuclear Ca(2+) release. In this review, we discuss mechanisms for the selective control of nuclear Ca(2+) signals with special focus on emerging models of agonist receptor activation.
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Affiliation(s)
- Cristián Ibarra
- Cardiovascular and Metabolic Diseases, Innovative Medicines and Early Development, AstraZeneca R&D, Mölndal, Sweden.
| | - Jose Miguel Vicencio
- Hatter Cardiovascular Institute, University College London, London, United Kingdom
| | - Manuel Varas-Godoy
- Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden
| | - Enrique Jaimovich
- Centro de Estudios Moleculares de la Célula, Facultad de Ciencias Químicas y Farmacéuticas & Facultad de Medicina, Universidad de Chile, Santiago, Chile
| | - Beverly A Rothermel
- Department of Internal Medicine, Cardiology Division, University of Texas Southwestern Medical Center, Dallas, TX, USA; Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Per Uhlén
- Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden
| | - Joseph A Hill
- Department of Internal Medicine, Cardiology Division, University of Texas Southwestern Medical Center, Dallas, TX, USA; Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Sergio Lavandero
- Centro de Estudios Moleculares de la Célula, Facultad de Ciencias Químicas y Farmacéuticas & Facultad de Medicina, Universidad de Chile, Santiago, Chile; Department of Internal Medicine, Cardiology Division, University of Texas Southwestern Medical Center, Dallas, TX, USA; Advanced Center for Chronic Diseases, Facultad de Ciencias Químicas y Farmacéuticas & Facultad de Medicina, Universidad de Chile, Santiago, Chile.
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Kapoor N, Maxwell JT, Mignery GA, Will D, Blatter LA, Banach K. Spatially defined InsP3-mediated signaling in embryonic stem cell-derived cardiomyocytes. PLoS One 2014; 9:e83715. [PMID: 24409283 PMCID: PMC3883750 DOI: 10.1371/journal.pone.0083715] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2013] [Accepted: 11/06/2013] [Indexed: 11/19/2022] Open
Abstract
The functional role of inositol 1,4,5-trisphosphate (InsP3) signaling in cardiomyocytes is not entirely understood but it was linked to an increased propensity for triggered activity. The aim of this study was to determine how InsP3 receptors can translate Ca(2+) release into a depolarization of the plasma membrane and consequently arrhythmic activity. We used embryonic stem cell-derived cardiomyocytes (ESdCs) as a model system since their spontaneous electrical activity depends on InsP3-mediated Ca(2+) release. [InsP3]i was monitored with the FRET-based InsP3-biosensor FIRE-1 (Fluorescent InsP3 Responsive Element) and heterogeneity in sub-cellular [InsP3]i was achieved by targeted expression of FIRE-1 in the nucleus (FIRE-1nuc) or expression of InsP3 5-phosphatase (m43) localized to the plasma membrane. Spontaneous activity of ESdCs was monitored simultaneously as cytosolic Ca(2+) transients (Fluo-4/AM) and action potentials (current clamp). During diastole, the diastolic depolarization was paralleled by an increase of [Ca(2+)]i and spontaneous activity was modulated by [InsP3]i. A 3.7% and 1.7% increase of FIRE-1 FRET ratio and 3.0 and 1.5 fold increase in beating frequency was recorded upon stimulation with endothelin-1 (ET-1, 100 nmol/L) or phenylephrine (PE, 10 µmol/L), respectively. Buffering of InsP3 by FIRE-1nuc had no effect on the basal frequency while attenuation of InsP3 signaling throughout the cell (FIRE-1), or at the plasma membrane (m43) resulted in a 53.7% and 54.0% decrease in beating frequency. In m43 expressing cells the response to ET-1 was completely suppressed. Ca(2+) released from InsP3Rs is more effective than Ca(2+) released from RyRs to enhance INCX. The results support the hypothesis that in ESdCs InsP3Rs form a functional signaling domain with NCX that translates Ca(2+) release efficiently into a depolarization of the membrane potential.
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Affiliation(s)
- Nidhi Kapoor
- Heart Institute, Cedars-Sinai Medical Center, Los Angeles, California, United States of America
| | - Joshua T. Maxwell
- Department of Molecular Biophysics and Physiology, Rush University Medical Center, Chicago, Illinois, United States of America
| | - Gregory A. Mignery
- Department of Cell and Molecular Physiology, Stritch School of Medicine, Loyola University Chicago, Maywood, Illinois, United States of America
| | - David Will
- Center for Cardiovascular Research, Dept. of Medicine, Section of Cardiology, University of Illinois at Chicago, Chicago, Illinois, United States of America
| | - Lothar A. Blatter
- Department of Molecular Biophysics and Physiology, Rush University Medical Center, Chicago, Illinois, United States of America
| | - Kathrin Banach
- Center for Cardiovascular Research, Dept. of Medicine, Section of Cardiology, University of Illinois at Chicago, Chicago, Illinois, United States of America
- * E-mail:
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14
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Fedorenko OA, Popugaeva E, Enomoto M, Stathopulos PB, Ikura M, Bezprozvanny I. Intracellular calcium channels: inositol-1,4,5-trisphosphate receptors. Eur J Pharmacol 2013; 739:39-48. [PMID: 24300389 DOI: 10.1016/j.ejphar.2013.10.074] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2013] [Revised: 09/28/2013] [Accepted: 10/17/2013] [Indexed: 01/13/2023]
Abstract
The inositol-1,4,5-trisphosphate receptors (InsP3Rs) are the major intracellular Ca(2+)-release channels in cells. Activity of InsP3Rs is essential for elementary and global Ca(2+) events in the cell. There are three InsP3Rs isoforms that are present in mammalian cells. In this review we will focus primarily on InsP3R type 1. The InsP3R1 is a predominant isoform in neurons and it is the most extensively studied isoform. Combination of biophysical and structural methods revealed key mechanisms of InsP3R function and modulation. Cell biological and biochemical studies lead to identification of a large number of InsP3R-binding proteins. InsP3Rs are involved in the regulation of numerous physiological processes, including learning and memory, proliferation, differentiation, development and cell death. Malfunction of InsP3R1 play a role in a number of neurodegenerative disorders and other disease states. InsP3Rs represent a potentially valuable drug target for treatment of these disorders and for modulating activity of neurons and other cells. Future studies will provide better understanding of physiological functions of InsP3Rs in health and disease.
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Affiliation(s)
- Olena A Fedorenko
- Department of Brain Physiology, Bogomoletz Institute of Physiology, 01024 Kiev, Ukraine; State Key Laboratory of Molecular and Cellular Biology, 01024 Kiev, Ukraine
| | - Elena Popugaeva
- Laboratory of Molecular Neurodegeneration, Department of Medical Physics, St. Petersburg State Polytechnical University, 195251 St. Petersburg, Russia
| | - Masahiro Enomoto
- Princess Margaret Cancer Centre, Department of Medical Biophysics, University of Toronto, M5G1L7 Toronto, Ontario, Canada
| | - Peter B Stathopulos
- Princess Margaret Cancer Centre, Department of Medical Biophysics, University of Toronto, M5G1L7 Toronto, Ontario, Canada
| | - Mitsuhiko Ikura
- Princess Margaret Cancer Centre, Department of Medical Biophysics, University of Toronto, M5G1L7 Toronto, Ontario, Canada
| | - Ilya Bezprozvanny
- Laboratory of Molecular Neurodegeneration, Department of Medical Physics, St. Petersburg State Polytechnical University, 195251 St. Petersburg, Russia; Department of Physiology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA.
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Gaspers LD, Mémin E, Thomas AP. Calcium-dependent physiologic and pathologic stimulus-metabolic response coupling in hepatocytes. Cell Calcium 2012; 52:93-102. [PMID: 22564906 DOI: 10.1016/j.ceca.2012.04.009] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2012] [Revised: 04/13/2012] [Accepted: 04/16/2012] [Indexed: 01/19/2023]
Abstract
A recurrent paradigm in calcium signaling is the coordination of the target response of the calcium signal with activation of metabolic energy production to support that response. This occurs in many tissues, including cardiac and skeletal muscle where contractile activity and ATP production are coordinately regulated by the frequency and amplitude of calcium transients, endocrine and exocrine cells that use calcium to drive the secretory process, and hepatocytes where the downstream targets of calcium include both catabolic and anabolic processes. The primary mechanism by which calcium enhances the capacity for energy production is through calcium-dependent stimulation of mitochondrial oxidative metabolism, achieved by increasing NADH production and respiratory chain flux. Although this enhances energy supply, it also has the potential for deleterious consequences resulting from increased generation of reactive oxygen species (ROS). The negative consequences of calcium-dependent mitochondrial activation can be ameliorated when the underlying cytosolic calcium signals occur as brief calcium spikes or oscillations, with signal strength encoded through the spike frequency (frequency modulation). Frequency modulation increases signal fidelity, and reduces pathological effects of calcium, including excess mitochondrial ROS production and apoptotic or necrotic outcomes. The present article reviews these issues using data obtained in hepatocytes under physiologic and pathologic conditions.
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Affiliation(s)
- Lawrence D Gaspers
- Department of Pharmacology and Physiology, University of Medicine and Dentistry of New Jersey, 185 South Orange Avenue, Newark, NJ 07103, United States.
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Abstract
After partial hepatectomy (PH) the initial mass of the organ is restored through a complex network of cellular interactions that orchestrate both proliferative and hepatoprotective signalling cascades. Among agonists involved in this network many of them drive Ca(2+) movements. During liver regeneration in the rat, hepatocyte cytosolic Ca(2+) signalling has been shown on the one hand to be deeply remodelled and on the other hand to enhance progression of hepatocytes through the cell cycle. Mechanisms through which cytosolic Ca(2+) signals impact on hepatocyte cell cycle early after PH are not completely understood, but at least they include regulation of immediate early gene transcription and ERK and CREB phosphorylation. In addition to cytosolic Ca(2+), there is also evidence that mitochondrial Ca(2+) and also nuclear Ca(2+) may be critical for the regulation of liver regeneration. Finally, Ca(2+) movements in hepatocytes, and possibly in other liver cells, not only impact hepatocyte progression in the cell cycle but more generally may regulate cellular homeostasis after PH.
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Bkaily G, Avedanian L, Al-Khoury J, Provost C, Nader M, D'Orléans-Juste P, Jacques D. Nuclear membrane receptors for ET-1 in cardiovascular function. Am J Physiol Regul Integr Comp Physiol 2011; 300:R251-63. [DOI: 10.1152/ajpregu.00736.2009] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Plasma membrane endothelin type A (ETA) receptors are internalized and recycled to the plasma membrane, whereas endothelin type B (ETB) receptors undergo degradation and subsequent nuclear translocation. Recent studies show that G protein-coupled receptors (GPCRs) and ion transporters are also present and functional at the nuclear membranes of many cell types. Similarly to other GPCRs, ETA and ETB are present at both the plasma and nuclear membranes of several cardiovascular cell types, including human cardiac, vascular smooth muscle, endocardial endothelial, and vascular endothelial cells. The distribution and density of ETARs in the cytosol (including the cell membrane) and the nucleus (including the nuclear membranes) differ between these cell types. However, the localization and density of ET-1 and ETB receptors are similar in these cell types. The extracellular ET-1-induced increase in cytosolic ([Ca]c) and nuclear ([Ca]n) free Ca2+ is associated with an increase of cytosolic and nuclear reactive oxygen species. The extracellular ET-1-induced increase of [Ca]c and [Ca]n as well as intracellular ET-1-induced increase of [Ca]n are cell-type dependent. The type of ET-1 receptor mediating the extracellular ET-1-induced increase of [Ca]c and [Ca]n depends on the cell type. However, the cytosolic ET-1-induced increase of [Ca]n does not depend on cell type. In conclusion, nuclear membranes' ET-1 receptors may play an important role in overall ET-1 action. These nuclear membrane ET-1 receptors could be targets for a new generation of antagonists.
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Affiliation(s)
- Ghassan Bkaily
- Faculty of Medicine, Departments of 1Anatomy and Cell Biology and
| | - Levon Avedanian
- Faculty of Medicine, Departments of 1Anatomy and Cell Biology and
| | - Johny Al-Khoury
- Faculty of Medicine, Departments of 1Anatomy and Cell Biology and
| | - Chantale Provost
- Faculty of Medicine, Departments of 1Anatomy and Cell Biology and
| | - Moni Nader
- Faculty of Medicine, Departments of 1Anatomy and Cell Biology and
| | | | - Danielle Jacques
- Faculty of Medicine, Departments of 1Anatomy and Cell Biology and
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18
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Valdehita A, Bajo AM, Fernández-Martínez AB, Arenas MI, Vacas E, Valenzuela P, Ruíz-Villaespesa A, Prieto JC, Carmena MJ. Nuclear localization of vasoactive intestinal peptide (VIP) receptors in human breast cancer. Peptides 2010; 31:2035-45. [PMID: 20691743 DOI: 10.1016/j.peptides.2010.07.024] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/15/2010] [Revised: 07/28/2010] [Accepted: 07/28/2010] [Indexed: 12/12/2022]
Abstract
Vasoactive intestinal peptide (VIP) and its receptors (VPACs) are involved in proliferation, survival, and differentiation in human breast cancer cells. Its mechanism of action is traditionally thought to be through specific plasma membrane receptors. There is compelling evidence for a novel intracrine mode of genomic regulation by G-protein-coupled receptors (GPCRs) that implies both endocytosis and nuclear translocation of peripheral GPCR and/or the activation of nuclear-located GPCRs by endogenously-produced, non-secreted ligands. Regarding to VPAC receptors, which are GPCRs, there is only a report suggesting them as a dynamic system for signaling from plasma membrane and nuclear membrane complex. In this study, we show that VPAC(1) receptor is localized in cell nuclear fraction whereas VPAC(2) receptor presents an extranuclear localization and its protein expression is lower than that of VPAC(1) receptor in human breast tissue samples. Both receptors as well as VIP are overexpressed in breast cancer as compared to non-tumor tissue. Moreover, we report the markedly nuclear localization of VPAC(1) receptors in estrogen-dependent (T47D) and independent (MDA-MB-468) human breast cancer cell lines. VPAC(1) receptors are functional in plasma membrane and nucleus as shown by VIP stimulation of cAMP production in both cell lines. In addition, VIP increases its own intracellular and extracellular levels, and could be involved in the regulation of VPAC(1)-receptor traffic from the plasma membrane to the nucleus. These results support new concepts on function and regulation of nuclear GPCRs which could have an impact on development of new therapeutic drugs.
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Affiliation(s)
- Ana Valdehita
- Molecular Neuroendocrinology Unit, Department of Biochemistry and Molecular Biology, Alcalá University, 28871 Alcalá de Henares, Spain
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19
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Mothersill C, Saroya R, Smith RW, Singh H, Seymour CB. Serum serotonin levels determine the magnitude and type of bystander effects in medium transfer experiments. Radiat Res 2010; 174:119-23. [PMID: 20681806 DOI: 10.1667/rr2036.1] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Serotonin has been shown to be involved in the production of bystander signals by irradiated cells. In this study we examined the levels of serotonin in 10 different batches of commercially available fetal calf serum and correlated the serotonin levels with the toxicity of medium harvested from irradiated cells (ICCM) using a standard medium transfer colony-forming assay. The serotonin levels in the serum varied widely between batches, and the levels correlated directly with the toxicity of the harvested ICCM. Three serum samples had levels of serotonin below 25 ng/ml, and these did not show medium transfer bystander effects. Exposure of serum samples to normal daylight reduced serotonin levels significantly. We suggest that serum batch variability may underlie much of the observed interlaboratory variation in the ability to produce bystander effects and further suggest that serum batches should be protected from light and prescreened for their ability to produce a bystander effect using a positive control cell line.
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Affiliation(s)
- Carmel Mothersill
- Medical Physics and Applied Radiation Science Centre, McMaster University, Hamilton, Ontario, Canada, L8S 4K1.
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20
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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.
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Affiliation(s)
- Colin W Taylor
- Department of Pharmacology, University of Cambridge, Cambridge, UK.
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21
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Sieberer BJ, Chabaud M, Timmers AC, Monin A, Fournier J, Barker DG. A nuclear-targeted cameleon demonstrates intranuclear Ca2+ spiking in Medicago truncatula root hairs in response to rhizobial nodulation factors. PLANT PHYSIOLOGY 2009; 151:1197-206. [PMID: 19700563 PMCID: PMC2773104 DOI: 10.1104/pp.109.142851] [Citation(s) in RCA: 110] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
Lipochitooligosaccharide nodulation factors (NFs) secreted by endosymbiotic nitrogen-fixing rhizobia trigger Ca(2+) spiking in the cytoplasmic perinuclear region of host legume root hairs. To determine whether NFs also elicit Ca(2+) responses within the plant cell nucleus we have made use of a nucleoplasmin-tagged cameleon (NupYC2.1). Confocal microscopy using this nuclear-specific calcium reporter has revealed sustained and regular Ca(2+) spiking within the nuclear compartment of Medicago truncatula root hairs treated with Sinorhizobium meliloti NFs. Since the activation of Ca(2+) oscillations is blocked in M. truncatula nfp, dmi1, and dmi2 mutants, and unaltered in a dmi3 background, it is likely that intranuclear spiking lies on the established NF-dependent signal transduction pathway, leading to cytoplasmic calcium spiking. A semiautomated mathematical procedure has been developed to identify and analyze nuclear Ca(2+) spiking profiles, and has revealed high cell-to-cell variability in terms of both periodicity and spike duration. Time-lapse imaging of the cameleon Förster resonance energy transfer-based ratio has allowed us to visualize the nuclear spiking variability in situ and to demonstrate the absence of spiking synchrony between adjacent growing root hairs. Finally, spatio-temporal analysis of the asymmetric nuclear spike suggests that the initial rapid increase in Ca(2+) concentration occurs principally in the vicinity of the nuclear envelope. The discovery that rhizobial NF perception leads to the activation of cell-autonomous Ca(2+) oscillations on both sides of the nuclear envelope raises major questions about the respective roles of the cytoplasmic and nuclear compartments in transducing this key endosymbiotic signal.
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Bootman MD, Fearnley C, Smyrnias I, MacDonald F, Roderick HL. An update on nuclear calcium signalling. J Cell Sci 2009; 122:2337-50. [PMID: 19571113 DOI: 10.1242/jcs.028100] [Citation(s) in RCA: 149] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Over the past 15 years or so, numerous studies have sought to characterise how nuclear calcium (Ca2+) signals are generated and reversed, and to understand how events that occur in the nucleoplasm influence cellular Ca2+ activity, and vice versa. In this Commentary, we describe mechanisms of nuclear Ca2+ signalling and discuss what is known about the origin and physiological significance of nuclear Ca2+ transients. In particular, we focus on the idea that the nucleus has an autonomous Ca2+ signalling system that can generate its own Ca2+ transients that modulate processes such as gene transcription. We also discuss the role of nuclear pores and the nuclear envelope in controlling ion flux into the nucleoplasm.
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Affiliation(s)
- Martin D Bootman
- Laboratory of Molecular Signalling, The Babraham Institute, Babraham, Cambridge CB22 3AT, UK.
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23
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Hwang JY, Duncan RS, Madry C, Singh M, Koulen P. Progesterone potentiates calcium release through IP3 receptors by an Akt-mediated mechanism in hippocampal neurons. Cell Calcium 2008; 45:233-42. [PMID: 19081133 DOI: 10.1016/j.ceca.2008.10.006] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2008] [Revised: 08/29/2008] [Accepted: 10/26/2008] [Indexed: 12/19/2022]
Abstract
Progesterone (P4) is a steroid hormone that plays multiple roles in the central nervous system (CNS) including promoting neuroprotection. However, the precise mechanisms involved in its neuroprotective effects are still unknown. Given that the regulation of the intracellular calcium (Ca(2+)) concentration is critical for cell survival, we determined if inositol 1, 4, 5-trisphosphate receptors (IP(3)Rs) are relevant targets of P4. Using primary hippocampal neurons, we tested the hypothesis that P4 controls the gain of IP3R-mediated intracellular Ca(2+) signaling in neurons and characterized the subcellular distribution and phosphorylation of potential signaling intermediates involved in P4s actions. Our results reveal that P4 treatment altered the intensity and distribution of IP3R immunoreactivity and induced the nuclear translocation of phosphorylated Akt. Further, P4 potentiated IP(3)R-mediated intracellular Ca(2+) responses. These results suggest a potential involvement of P4 in particular and of steroid hormone signaling pathways in general in the control of intracellular Ca(2+) signaling and its related functions.
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Affiliation(s)
- Ji-yeon Hwang
- Department of Pharmacology and Neuroscience, University of North Texas Health Science Center at Fort Worth, 3500 Camp Bowie Blvd., Fort Worth, TX 76107-2699, USA
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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.
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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
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25
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Wojda U, Salinska E, Kuznicki J. Calcium ions in neuronal degeneration. IUBMB Life 2008; 60:575-90. [PMID: 18478527 DOI: 10.1002/iub.91] [Citation(s) in RCA: 206] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Neuronal Ca(2+) homeostasis and Ca(2+) signaling regulate multiple neuronal functions, including synaptic transmission, plasticity, and cell survival. Therefore disturbances in Ca(2+) homeostasis can affect the well-being of the neuron in different ways and to various degrees. Ca(2+) homeostasis undergoes subtle dysregulation in the physiological ageing. Products of energy metabolism accumulating with age together with oxidative stress gradually impair Ca(2+) homeostasis, making neurons more vulnerable to additional stress which, in turn, can lead to neuronal degeneration. Neurodegenerative diseases related to aging, such as Alzheimer's disease, Parkinson's disease, or Huntington's disease, develop slowly and are characterized by the positive feedback between Ca(2+) dyshomeostasis and the aggregation of disease-related proteins such as amyloid beta, alfa-synuclein, or huntingtin. Ca(2+) dyshomeostasis escalates with time eventually leading to neuronal loss. Ca(2+) dyshomeostasis in these chronic pathologies comprises mitochondrial and endoplasmic reticulum dysfunction, Ca(2+) buffering impairment, glutamate excitotoxicity and alterations in Ca(2+) entry routes into neurons. Similar changes have been described in a group of multifactorial diseases not related to ageing, such as epilepsy, schizophrenia, amyotrophic lateral sclerosis, or glaucoma. Dysregulation of Ca(2+) homeostasis caused by HIV infection or by sudden accidents, such as brain stroke or traumatic brain injury, leads to rapid neuronal death. The differences between the distinct types of Ca(2+) dyshomeostasis underlying neuronal degeneration in various types of pathologies are not clear. Questions that should be addressed concern the sequence of pathogenic events in an affected neuron and the pattern of progressive degeneration in the brain itself. Moreover, elucidation of the selective vulnerability of various types of neurons affected in the diseases described here will require identification of differences in the types of Ca(2+) homeostasis and signaling among these neurons. This information will be required for improved targeting of Ca(2+) homeostasis and signaling components in future therapeutic strategies, since no effective treatment is currently available to prevent neuronal degeneration in any of the pathologies described here.
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Affiliation(s)
- Urszula Wojda
- Laboratory of Neurodegeneration, International Institute of Molecular and Cell Biology, Ks. Trojdena 4, 02-109 Warsaw, Poland.
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Kockskämper J, Zima AV, Roderick HL, Pieske B, Blatter LA, Bootman MD. Emerging roles of inositol 1,4,5-trisphosphate signaling in cardiac myocytes. J Mol Cell Cardiol 2008; 45:128-47. [PMID: 18603259 PMCID: PMC2654363 DOI: 10.1016/j.yjmcc.2008.05.014] [Citation(s) in RCA: 142] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/03/2008] [Revised: 05/20/2008] [Accepted: 05/21/2008] [Indexed: 01/19/2023]
Abstract
Inositol 1,4,5-trisphosphate (IP(3)) is a ubiquitous intracellular messenger regulating diverse functions in almost all mammalian cell types. It is generated by membrane receptors that couple to phospholipase C (PLC), an enzyme which liberates IP(3) from phosphatidylinositol 4,5-bisphosphate (PIP(2)). The major action of IP(3), which is hydrophilic and thus translocates from the membrane into the cytoplasm, is to induce Ca(2+) release from endogenous stores through IP(3) receptors (IP(3)Rs). Cardiac excitation-contraction coupling relies largely on ryanodine receptor (RyR)-induced Ca(2+) release from the sarcoplasmic reticulum. Myocytes express a significantly larger number of RyRs compared to IP(3)Rs (~100:1), and furthermore they experience substantial fluxes of Ca(2+) with each heartbeat. Therefore, the role of IP(3) and IP(3)-mediated Ca(2+) signaling in cardiac myocytes has long been enigmatic. Recent evidence, however, indicates that despite their paucity cardiac IP(3)Rs may play crucial roles in regulating diverse cardiac functions. Strategic localization of IP(3)Rs in cytoplasmic compartments and the nucleus enables them to participate in subsarcolemmal, bulk cytoplasmic and nuclear Ca(2+) signaling in embryonic stem cell-derived and neonatal cardiomyocytes, and in adult cardiac myocytes from the atria and ventricles. Intriguingly, expression of both IP(3)Rs and membrane receptors that couple to PLC/IP(3) signaling is altered in cardiac disease such as atrial fibrillation or heart failure, suggesting the involvement of IP(3) signaling in the pathology of these diseases. Thus, IP(3) exerts important physiological and pathological functions in the heart, ranging from the regulation of pacemaking, excitation-contraction and excitation-transcription coupling to the initiation and/or progression of arrhythmias, hypertrophy and heart failure.
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Affiliation(s)
- Jens Kockskämper
- Division of Cardiology, Medical University of Graz,, Auenbruggerplatz 15, A-8036 Graz, Austria
| | - Aleksey V. Zima
- Department of Molecular Biophysics & Physiology, Rush University, 1750 W. Harrison St., Chicago, IL 60612, USA
| | - H. Llewelyn Roderick
- Laboratory of Molecular Signalling, Babraham Institute, Cambridge CB2 4AT, UK
- Department of Pharmacology, University of Cambridge, Tennis Court Road, Cambridge CB2 1 PD, UK
| | - Burkert Pieske
- Division of Cardiology, Medical University of Graz,, Auenbruggerplatz 15, A-8036 Graz, Austria
| | - Lothar A. Blatter
- Department of Molecular Biophysics & Physiology, Rush University, 1750 W. Harrison St., Chicago, IL 60612, USA
| | - Martin D. Bootman
- Laboratory of Molecular Signalling, Babraham Institute, Cambridge CB2 4AT, UK
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Bezin S, Charpentier G, Lee HC, Baux G, Fossier P, Cancela JM. Regulation of nuclear Ca2+ signaling by translocation of the Ca2+ messenger synthesizing enzyme ADP-ribosyl cyclase during neuronal depolarization. J Biol Chem 2008; 283:27859-27870. [PMID: 18632662 DOI: 10.1074/jbc.m804701200] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
In neurons, voltage-gated Ca(2+) channels and nuclear Ca(2+) signaling play important roles, such as in the regulation of gene expression. However, the link between electrical activity and biochemical cascade activation involved in the generation of the nuclear Ca(2+) signaling is poorly understood. Here we show that depolarization of Aplysia neurons induces the translocation of ADP-ribosyl cyclase, a Ca(2+) messenger synthesizing enzyme, from the cytosol into the nucleus. The translocation is dependent on Ca(2+) influx mainly through the voltage-dependent L-type Ca(2+) channels. We report also that specific nucleoplasmic Ca(2+) signals can be induced by three different calcium messengers, cyclic ADP-ribose, nicotinic acid adenine dinucleotide phosphate (NAADP), both produced by the ADP-ribosyl cyclase, and inositol 1,4,5-trisphosphate (IP(3)). Moreover, our pharmacological data show that NAADP acts on its own receptor, which cooperates with the IP(3) and the ryanodine receptors to generate nucleoplasmic Ca(2+) oscillations. We propose a new model where voltage-dependent L-type Ca(2+) channel-induced nuclear translocation of the cytosolic cyclase is a crucial step in the fine tuning of nuclear Ca(2+) signals in neurons.
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Affiliation(s)
- Stéphanie Bezin
- Laboratoire de Neurobiologie Cellulaire et Moléculaire, CNRS, UPR 9040, 1, Avenue de la Terrasse, 91198 Gif-Sur-Yvette Cedex, France
| | - Gilles Charpentier
- Laboratoire de Neurobiologie Cellulaire et Moléculaire, CNRS, UPR 9040, 1, Avenue de la Terrasse, 91198 Gif-Sur-Yvette Cedex, France; Université Bordeaux 1 Laboratoire DMPFCS, IECB, 2, Rue Robert Escarpit, 33607 Pessac, France
| | - Hon Cheung Lee
- Department of Physiology, University of Hong Kong, 4/F Lab Block, Faculty of Medicine Building, 21 Sassoon Road, Hong Kong
| | - Gérard Baux
- Laboratoire de Neurobiologie Cellulaire et Moléculaire, CNRS, UPR 9040, 1, Avenue de la Terrasse, 91198 Gif-Sur-Yvette Cedex, France
| | - Philippe Fossier
- Laboratoire de Neurobiologie Cellulaire et Moléculaire, CNRS, UPR 9040, 1, Avenue de la Terrasse, 91198 Gif-Sur-Yvette Cedex, France
| | - José-Manuel Cancela
- Laboratoire de Neurobiologie Cellulaire et Moléculaire, CNRS, UPR 9040, 1, Avenue de la Terrasse, 91198 Gif-Sur-Yvette Cedex, France.
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Vartiainen MK. Nuclear actin dynamics--from form to function. FEBS Lett 2008; 582:2033-40. [PMID: 18423404 DOI: 10.1016/j.febslet.2008.04.010] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2008] [Revised: 03/28/2008] [Accepted: 04/09/2008] [Indexed: 01/10/2023]
Abstract
Cell biological functions of actin have recently expanded from cytoplasm to nucleus, with actin implicated in such diverse processes as gene expression, transcription factor regulation and intranuclear motility. Actin in the nucleus seems to behave differently than in the cytoplasm, raising new questions regarding the molecular mechanisms by which actin functions in cells. In this review, I will discuss dynamic properties of nuclear actin that are related to its polymerization cycle and nucleocytoplasmic shuttling. By comparing the behaviour of nuclear and cytoplasmic actin and their regulators, I try to dissect the underlying differences of these equally important cellular actin pools.
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Affiliation(s)
- Maria K Vartiainen
- Research Program in Cellular Biotechnology, Institute of Biotechnology, University of Helsinki, Viikinkaari 9, 00014 Helsinki, Finland.
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VanHouten JN, Wysolmerski JJ. Transcellular calcium transport in mammary epithelial cells. J Mammary Gland Biol Neoplasia 2007; 12:223-35. [PMID: 17999165 DOI: 10.1007/s10911-007-9057-1] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/10/2007] [Accepted: 10/25/2007] [Indexed: 10/22/2022] Open
Abstract
The time-honored paradigm for mammary gland transepithelial calcium transport into milk is centered on the view that most, if not all, calcium enters milk through the secretory pathway, and no ionic calcium directly crosses the apical plasma membrane. Data from several recent studies all strongly suggest that most calcium, in fact, is extruded across the apical plasma membrane directly by the plasma membrane calcium-ATPase isoform 2 (PMCA2). In this review we break down transcellular calcium transport into the tasks of calcium entry, calcium sequestration and compartmentalization, and calcium extrusion. We compare and contrast the steps of calcium transport into milk by mammary epithelial cells, and the specific molecules that might perform these tasks, with well-characterized calcium transport mechanisms in other epithelia, such as the kidney, small intestine, and salivary gland. Finally, we suggest an updated model for calcium transport into milk that incorporates calcium transport across the apical plasma membrane.
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Affiliation(s)
- Joshua N VanHouten
- Section of Endocrinology and Metabolism, Department of Internal Medicine, Yale University School of Medicine, P.O. Box 208020, New Haven, CT 06520-8020, USA.
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Juretić N, Urzúa U, Munroe DJ, Jaimovich E, Riveros N. Differential gene expression in skeletal muscle cells after membrane depolarization. J Cell Physiol 2007; 210:819-30. [PMID: 17146758 DOI: 10.1002/jcp.20902] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Skeletal muscle is a highly plastic tissue with a remarkable capacity to adapt itself to challenges imposed by contractile activity. Adaptive response, that include hypertrophy and activation of oxidative mechanisms have been associated with transient changes in transcriptional activity of specific genes. To define the set of genes regulated by a depolarizing stimulus, we used 22 K mouse oligonucleotide microarrays. Total RNA from C2C12 myotubes was obtained at 2, 4, 18, and 24 h after high K+ stimulation. cDNA from control and depolarized samples was labeled with cyanine 3 or 5 dyes prior to microarray hybridization. Loess normalization followed by statistical analysis resulted in 423 differentially expressed genes using an unadjusted P-value < or = 0.01 as cut off. Depolarization affects transcriptional activity of a limited number of genes, mainly associated with metabolism, cell communication and response to stress. A number of genes related to Ca2+ signaling pathways are induced at 4 h, reinforcing the potential role of Ca2+ in early steps of signal transduction that leads to gene expression. Significant changes in the expression of molecules involved in muscle cell structure were observed; K+-depolarization increased Tnni1 and Acta1 mRNA levels in both differentiated C2C12 and rat skeletal muscle cells in primary culture. Of these two, depolarization induced slow Ca2+ transients appear to have a role only in the regulation of Tnni1 transcriptional activity. We suggest that depolarization induced expression of a small set of genes may underlie Ca2+ dependent plasticity of skeletal muscle cells.
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Affiliation(s)
- Nevenka Juretić
- Centro de Estudios Moleculares de la Célula, Facultad de Medicina, Instituto de Ciencias Biomédicas, Universidad de Chile, Santiago, Chile
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Chan CB, Ye K, Chan CB, Ye K. PIKE GTPase are phosphoinositide-3-kinase enhancers, suppressing programmed cell death. J Cell Mol Med 2007; 11:39-53. [PMID: 17367500 PMCID: PMC4401219 DOI: 10.1111/j.1582-4934.2007.00014.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2006] [Accepted: 01/05/2007] [Indexed: 01/05/2023] Open
Abstract
Phosphoinositide-3-kinase enhancers (PIKE) are GTP-binding proteins that posses anti-apoptotic functions. The PIKE family includes three members, PIKE-L, PIKE-S and PIKE-A, which are originated from a single gene (CENTG1) through alternative splicing or differential transcription initiation. Both PIKE-S and PIKE-L bind to phosphoinositide-3-kinase (PI3K) and enhance its activity. PIKE-A does not interplay with PI3K. Instead, it interacts with the downstream effector Akt and promotes its activity. These actions are mediated by their GTPase activity. Because both PI3K and Akt are important effectors in the growth factor-mediated signaling which triggers cellular growth and acts against apoptosis, PIKEs therefore serve as the molecular switch that their activation are crucial for growth factors to exert their physiological functions. In this review, the current understanding of different PIKE isoforms in growth factors-induced anti-apoptotic function will be discussed. Moreover, the role of PIKE in the survival and invasion activity of cancer cells will also be introduced.
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Affiliation(s)
- Chi Bun Chan
- Department of Pathology and Laboratory Medicine, Emory University School of Medicine, Atlanta, GA, USA
| | - Keqiang Ye
- Department of Pathology and Laboratory Medicine, Emory University School of Medicine, Atlanta, GA, USA
| | - Chi Bun Chan
- Department of Pathology and Laboratory Medicine, Emory University School of Medicine, Atlanta, GA, USA
| | - Keqiang Ye
- Department of Pathology and Laboratory Medicine, Emory University School of Medicine, Atlanta, GA, USA
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