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Gao Y, Xu L, Li Y, Qi D, Wang C, Luan C, Zheng S, Du Q, Liu W, Lu G, Gong W, Ma X. Calcium transferring from ER to mitochondria via miR-129/ITPR2 axis controls cellular senescence in vitro and in vivo. Mech Ageing Dev 2024; 218:111902. [PMID: 38218462 DOI: 10.1016/j.mad.2024.111902] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2023] [Revised: 12/20/2023] [Accepted: 01/08/2024] [Indexed: 01/15/2024]
Abstract
Senescent cells are known to be accumulated in aged organisms. Although the two main characteristics, cell cycle arrest (for dividing cells) and secretion of senescence-associated secretory phenotype (SASP) factors, have been well described, the lack of sufficient senescent markers and incomplete understanding of mechanisms have limited the progress of the anti-senescence field. Calcium transferred from the endoplasmic reticulum (ER) via inositol 1, 4, 5-trisphosphate receptor type 2 (ITPR2) to mitochondria has emerged as a key player during cellular senescence and aging. However, the internal regulatory mechanisms, particularly those of endogenous molecules, remain only partially understood. Here we identified miRNA-129 (miR-129) as a direct repressor of ITPR2. Interestingly, miR-129 controlled a cascade of intracellular calcium signaling, mitochondrial membrane potential (MMP), reactive oxygen species (ROS), DNA damage, and consequently cellular senescence through ITPR2 and mitochondrial calcium uniporter (MCU). In addition, miR-129 was repressed in different senescence models and delayed bleomycin-induced cellular senescence. Importantly, intraperitoneal injection of miR-129 partly postponed bleomycin-accelerated lung aging and natural aging markers as well as reduced immunosenescence markers in mice. Altogether, these findings demonstrated that miR-129 regulated cellular senescence and aging markers via intracellular calcium signaling by directly targeting ITPR2.
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Affiliation(s)
- Yue Gao
- Department of The Central Laboratory, Department of Intensive Care, The Affiliated Hospital of Yangzhou University, Yangzhou University, Yangzhou, China; Department of Pathology, Northern Jiangsu People's Hospital, Yangzhou, China
| | - Lei Xu
- Department of The Central Laboratory, Department of Intensive Care, The Affiliated Hospital of Yangzhou University, Yangzhou University, Yangzhou, China
| | - Yaru Li
- Department of The Central Laboratory, Department of Intensive Care, The Affiliated Hospital of Yangzhou University, Yangzhou University, Yangzhou, China
| | - Dandan Qi
- Department of The Central Laboratory, Department of Intensive Care, The Affiliated Hospital of Yangzhou University, Yangzhou University, Yangzhou, China
| | - Chaofan Wang
- Department of The Central Laboratory, Department of Intensive Care, The Affiliated Hospital of Yangzhou University, Yangzhou University, Yangzhou, China
| | - Changjiao Luan
- Department of The Central Laboratory, Department of Intensive Care, The Affiliated Hospital of Yangzhou University, Yangzhou University, Yangzhou, China; Department of Lung, The Third People's Hospital of Yangzhou, Yangzhou, China
| | - Shihui Zheng
- Department of Molecular Biology, Inter faculty Institute of Cell Biology, Eberhard Karls University Tuebingen, Tuebingen, Germany
| | - Qiu Du
- Department of The Central Laboratory, Department of Intensive Care, The Affiliated Hospital of Yangzhou University, Yangzhou University, Yangzhou, China
| | - Weili Liu
- Department of The Central Laboratory, Department of Intensive Care, The Affiliated Hospital of Yangzhou University, Yangzhou University, Yangzhou, China
| | - Guotao Lu
- Department of Gastroenterology, The Affiliated Hospital of Yangzhou University, Yangzhou University, Yangzhou, China
| | - Weijuan Gong
- Department of Gastroenterology, The Affiliated Hospital of Yangzhou University, Yangzhou University, Yangzhou, China.
| | - Xingjie Ma
- Department of The Central Laboratory, Department of Intensive Care, The Affiliated Hospital of Yangzhou University, Yangzhou University, Yangzhou, China.
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Kodakandla G, Akimzhanov AM, Boehning D. Regulatory mechanisms controlling store-operated calcium entry. Front Physiol 2023; 14:1330259. [PMID: 38169682 PMCID: PMC10758431 DOI: 10.3389/fphys.2023.1330259] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2023] [Accepted: 12/08/2023] [Indexed: 01/05/2024] Open
Abstract
Calcium influx through plasma membrane ion channels is crucial for many events in cellular physiology. Cell surface stimuli lead to the production of inositol 1,4,5-trisphosphate (IP3), which binds to IP3 receptors (IP3R) in the endoplasmic reticulum (ER) to release calcium pools from the ER lumen. This leads to the depletion of ER calcium pools, which has been termed store depletion. Store depletion leads to the dissociation of calcium ions from the EF-hand motif of the ER calcium sensor Stromal Interaction Molecule 1 (STIM1). This leads to a conformational change in STIM1, which helps it to interact with the plasma membrane (PM) at ER:PM junctions. At these ER:PM junctions, STIM1 binds to and activates a calcium channel known as Orai1 to form calcium release-activated calcium (CRAC) channels. Activation of Orai1 leads to calcium influx, known as store-operated calcium entry (SOCE). In addition to Orai1 and STIM1, the homologs of Orai1 and STIM1, such as Orai2/3 and STIM2, also play a crucial role in calcium homeostasis. The influx of calcium through the Orai channel activates a calcium current that has been termed the CRAC current. CRAC channels form multimers and cluster together in large macromolecular assemblies termed "puncta". How CRAC channels form puncta has been contentious since their discovery. In this review, we will outline the history of SOCE, the molecular players involved in this process, as well as the models that have been proposed to explain this critical mechanism in cellular physiology.
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Affiliation(s)
- Goutham Kodakandla
- Department of Biomedical Sciences, Cooper Medical School of Rowan University, Camden, NJ, United States
| | - Askar M. Akimzhanov
- Department of Biochemistry and Molecular Biology, McGovern Medical School, Houston, TX, United States
| | - Darren Boehning
- Department of Biomedical Sciences, Cooper Medical School of Rowan University, Camden, NJ, United States
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Sotelo-Orozco J, Abbeduto L, Hertz-Picciotto I, Slupsky CM. Association Between Plasma Metabolites and Psychometric Scores Among Children With Developmental Disabilities: Investigating Sex-Differences. Front Psychiatry 2020; 11:579538. [PMID: 33414730 PMCID: PMC7783080 DOI: 10.3389/fpsyt.2020.579538] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/13/2020] [Accepted: 11/30/2020] [Indexed: 12/27/2022] Open
Abstract
Background: Developmental disabilities are defined by delays in learning, language, and behavior, yet growing evidence has revealed disturbances in metabolic systems that may also be present. Little is known about whether these metabolic issues contribute to the symptoms or severity of these disabilities, or whether sex plays a role in these associations, given that boys are disproportionately affected by some developmental disabilities. Here we sought to investigate the correlation between psychometric scores, sex, and the plasma metabolome. Methods: The plasma metabolomes of children with autism spectrum disorder (ASD; n = 167), idiopathic developmental delay (i-DD; n = 51), Down syndrome (DS; n = 31), and typically developing controls (TD; n = 193) were investigated using NMR spectroscopy. Spearman rank correlations and multiple linear regression models (adjusted for child's neurodevelopmental diagnosis, child's sex, child's age, child's race/ethnicity, maternal age at child's birth, and parental homeownership) were used to examine the association between plasma metabolites and sex in relation to psychometric measures of cognitive skills, adaptive behavior, and maladaptive behavior in our study population. Results: Higher levels of metabolites involved in cellular energy and mitochondrial function among children with ASD (fumarate and cis-aconitate), DS (lactate), and TD (pyruvate) are associated with poorer cognitive and adaptive subscales. Similarly, higher o-acetylcarnitine associated with deficits in cognitive subscales among all DS cases and TD boys, and carnitine correlated with increased maladaptive behavior among girls with ASD and girls with DS. Among children with DS, elevated myo-inositol, ornithine, and creatine correlated with poorer scores across several subscales. Even among TD cases, elevated 3-hydroxybutyrate correlated with decreased receptive language. In contrast, higher levels of glutamate were associated with better socialization skills among ASD cases. Even after adjusting for the child's neurodevelopmental diagnosis, sex, and other possible confounders, key metabolites including glycolysis metabolites (lactate and pyruvate), ketone bodies (3-hydroxybutyrate and acetoacetate), TCA cycle metabolites (cis-aconitate and fumarate), as well as ornithine were associated with deficits in multiple domains of cognitive function, adaptive skills, and aberrant behaviors. Conclusions: Our results highlight that some plasma metabolites may relate to specific functional subdomains within cognitive, adaptive, and behavioral development with some variation by diagnosis and sex.
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Affiliation(s)
- Jennie Sotelo-Orozco
- Department of Public Health Sciences, University of California, Davis, Davis, CA, United States
| | - Leonard Abbeduto
- Department of Psychiatry and Behavioral Sciences, University of California Davis Health, Sacramento, CA, United States
- MIND Institute, University of California Davis, Sacramento, CA, United States
| | - Irva Hertz-Picciotto
- Department of Public Health Sciences, University of California, Davis, Davis, CA, United States
| | - Carolyn M. Slupsky
- Department of Nutrition, University of California, Davis, Davis, CA, United States
- Department of Food Science and Technology, University of California, Davis, Davis, CA, United States
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Michon C, Kang CM, Karpenko S, Tanaka K, Ishikawa S, Yoshida KI. A bacterial cell factory converting glucose into scyllo-inositol, a therapeutic agent for Alzheimer's disease. Commun Biol 2020; 3:93. [PMID: 32123276 PMCID: PMC7052218 DOI: 10.1038/s42003-020-0814-7] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2019] [Accepted: 02/11/2020] [Indexed: 12/28/2022] Open
Abstract
A rare stereoisomer of inositol, scyllo-inositol, is a therapeutic agent that has shown potential efficacy in preventing Alzheimer’s disease. Mycobacterium tuberculosis ino1 encoding myo-inositol-1-phosphate (MI1P) synthase (MI1PS) was introduced into Bacillus subtilis to convert glucose-6-phosphate (G6P) into MI1P. We found that inactivation of pbuE elevated intracellular concentrations of NAD+·NADH as an essential cofactor of MI1PS and was required to activate MI1PS. MI1P thus produced was dephosphorylated into myo-inositol by an intrinsic inositol monophosphatase, YktC, which was subsequently isomerized into scyllo-inositol via a previously established artificial pathway involving two inositol dehydrogenases, IolG and IolW. In addition, both glcP and glcK were overexpressed to feed more G6P and accelerate scyllo-inositol production. Consequently, a B. subtilis cell factory was demonstrated to produce 2 g L−1scyllo-inositol from 20 g L−1 glucose. This cell factory provides an inexpensive way to produce scyllo-inositol, which will help us to challenge the growing problem of Alzheimer’s disease in our aging society. Michon et al. describe the use of a recombinant Bacillus subtilis as a cell factory capable of producing scyllo-inositol, a therapeutic compound for Alzheimer’s disease, from inexpensive glucose. They demonstrate that it could produce 2 g L−1 of scyllo-inositol from 20 g L−1 glucose.
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Affiliation(s)
- Christophe Michon
- Department of Science, Technology and Innovation, Kobe University, Kobe, 657 8501, Japan.,CHROMagar, 4 Place du 18 Juin 1940, 75006, Paris, France
| | - Choong-Min Kang
- Department of Biological Sciences, California State University, Stanislaus, Turlock, CA, 95382, USA
| | - Sophia Karpenko
- Department of Science, Technology and Innovation, Kobe University, Kobe, 657 8501, Japan.,Sorbonne Universités, UPMC Univ. Paris 06, UMR 8237, Laboratoire Jean Perrin, F-75005, Paris, France.,CNRS UMR 8237, Laboratoire Jean Perrin, F-75005, Paris, France.,Paris Sciences & Lettres, 60 rue Mazarine, F-75006, Paris, France
| | - Kosei Tanaka
- Department of Science, Technology and Innovation, Kobe University, Kobe, 657 8501, Japan
| | - Shu Ishikawa
- Department of Science, Technology and Innovation, Kobe University, Kobe, 657 8501, Japan
| | - Ken-Ichi Yoshida
- Department of Science, Technology and Innovation, Kobe University, Kobe, 657 8501, Japan.
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Orozco JS, Hertz-Picciotto I, Abbeduto L, Slupsky CM. Metabolomics analysis of children with autism, idiopathic-developmental delays, and Down syndrome. Transl Psychiatry 2019; 9:243. [PMID: 31582732 PMCID: PMC6776514 DOI: 10.1038/s41398-019-0578-3] [Citation(s) in RCA: 64] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/22/2019] [Revised: 09/04/2019] [Accepted: 09/16/2019] [Indexed: 02/06/2023] Open
Abstract
Although developmental delays affect learning, language, and behavior, some evidence suggests the presence of disturbances in metabolism are associated with psychiatric disorders. Here, the plasma metabolic phenotype of children with autism spectrum disorder (ASD, n = 167), idiopathic-developmental delay (i-DD, n = 51), and Down syndrome (DS, n = 31), as compared to typically developed (TD, n = 193) controls was investigated in a subset of children from the case-control Childhood Autism Risk from Genetics and the Environment (CHARGE) Study. Metabolome profiles were obtained using nuclear magnetic resonance spectroscopy and analyzed in an untargeted manner. Forty-nine metabolites were identified and quantified in each sample that included amino acids, organic acids, sugars, and other compounds. Multiple linear regression analysis revealed significant associations between 11 plasma metabolites and neurodevelopmental outcome. Despite the varied origins of these developmental disabilities, we observed similar perturbation in one-carbon metabolism pathways among DS and ASD cases. Similarities were also observed in the DS and i-DD cases in the energy-related tricarboxylic acid cycle. Other metabolites and pathways were uniquely associated with DS or ASD. By comparing metabolic signatures between these conditions, the current study expands on extant literature demonstrating metabolic alterations associated with developmental disabilities and provides a better understanding of overlapping vs specific biological perturbations associated with these disorders.
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Affiliation(s)
| | - Irva Hertz-Picciotto
- Department of Public Health Sciences, University of California, Davis, CA, 95616, USA
| | - Leonard Abbeduto
- Department of Psychiatry and Behavioral Sciences, University of California, Davis, CA, 95616, USA
- MIND Institute, University of California, Davis, CA, 95817, USA
| | - Carolyn M Slupsky
- Department of Nutrition, University of California, Davis, CA, 95616, USA.
- Department of Food Science and Technology, University of California, Davis, CA, 95616, USA.
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6
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Plasticity of Neuron-Glial Transmission: Equipping Glia for Long-Term Integration of Network Activity. Neural Plast 2015; 2015:765792. [PMID: 26339509 PMCID: PMC4539116 DOI: 10.1155/2015/765792] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2015] [Accepted: 06/11/2015] [Indexed: 01/28/2023] Open
Abstract
The capacity of synaptic networks to express activity-dependent changes in strength and connectivity is essential for learning and memory processes. In recent years, glial cells (most notably astrocytes) have been recognized as active participants in the modulation of synaptic transmission and synaptic plasticity, implicating these electrically nonexcitable cells in information processing in the brain. While the concept of bidirectional communication between neurons and glia and the mechanisms by which gliotransmission can modulate neuronal function are well established, less attention has been focussed on the computational potential of neuron-glial transmission itself. In particular, whether neuron-glial transmission is itself subject to activity-dependent plasticity and what the computational properties of such plasticity might be has not been explored in detail. In this review, we summarize current examples of plasticity in neuron-glial transmission, in many brain regions and neurotransmitter pathways. We argue that induction of glial plasticity typically requires repetitive neuronal firing over long time periods (minutes-hours) rather than the short-lived, stereotyped trigger typical of canonical long-term potentiation. We speculate that this equips glia with a mechanism for monitoring average firing rates in the synaptic network, which is suited to the longer term roles proposed for astrocytes in neurophysiology.
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Harrington JL, Murphy E. The mitochondrial calcium uniporter: mice can live and die without it. J Mol Cell Cardiol 2014; 78:46-53. [PMID: 25451167 DOI: 10.1016/j.yjmcc.2014.10.013] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/21/2014] [Revised: 10/23/2014] [Accepted: 10/26/2014] [Indexed: 01/27/2023]
Abstract
Calcium is of critical importance to mitochondrial and cell function, and calcium signaling is highly localized in the cell. When stimulated, mitochondria are capable of rapidly taking up calcium, affecting both matrix energetics within mitochondria and shaping the amplitude and frequency of cytosolic calcium "waves". During pathological conditions a large increase in mitochondrial calcium levels is thought to activate the mitochondrial permeability transition pore, resulting in cell death. The protein responsible for mitochondrial calcium uptake, the mitochondrial calcium uniporter (MCU), was identified in 2011 and its molecular elucidation has stimulated and invigorated research in this area. MCU knockout mice have been created, a variety of other regulators have been identified, and a disease phenotype in humans has been attributed to the loss of a uniporter regulator. In the three years since its molecular elucidation, further research into the MCU has revealed a complex uniporter, and raised many questions about its physiologic and pathologic cell roles. This article is part of a Special Issue entitled "Mitochondria: From Basic Mitochondrial Biology to Cardiovascular Disease".
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Hara A, Ebina S, Kondo A, Funaguma T. A New Type of Phytase from Pollen of Typha latifolia L. ACTA ACUST UNITED AC 2014. [DOI: 10.1080/00021369.1985.10867290] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Affiliation(s)
- Akira Hara
- Laboratory of Biological Chemistry, Faculty of Agriculture, Meijo University, Tenpaku-ku, Nagoya 468, Japan
| | - Shoetsu Ebina
- Laboratory of Biological Chemistry, Faculty of Agriculture, Meijo University, Tenpaku-ku, Nagoya 468, Japan
| | - Akihiko Kondo
- Laboratory of Biological Chemistry, Faculty of Agriculture, Meijo University, Tenpaku-ku, Nagoya 468, Japan
| | - Tooru Funaguma
- Laboratory of Biological Chemistry, Faculty of Agriculture, Meijo University, Tenpaku-ku, Nagoya 468, Japan
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9
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Putney JW, Tomita T. Phospholipase C signaling and calcium influx. Adv Biol Regul 2012; 52:152-64. [PMID: 21933679 PMCID: PMC3560308 DOI: 10.1016/j.advenzreg.2011.09.005] [Citation(s) in RCA: 115] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2011] [Accepted: 09/06/2011] [Indexed: 04/18/2023]
Affiliation(s)
- James W Putney
- Laboratory of Signal Transduction, National Institute of Environmental Health Sciences - NIH, Department of Health and Human Services, Research Triangle Park, NC 27709, USA.
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10
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Zhang ZY, Wang WJ, Pan LJ, Xu Y, Zhang ZM. Measuring Ca2+ influxes of TRPC1-dependent Ca2+ channels in HL-7702 cells with non-invasive micro-test technique. World J Gastroenterol 2009; 15:4150-5. [PMID: 19725149 PMCID: PMC2738811 DOI: 10.3748/wjg.15.4150] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
AIM To explore the possibility of using the Non-invasive Micro-test Technique (NMT) to investigate the role of Transient Receptor Potential Canonical 1 (TRPC1) in regulating Ca(2+) influxes in HL-7702 cells, a normal human liver cell line. METHODS Net Ca(2+) fluxes were measured with NMT, a technology that can obtain dynamic information of specific/selective ionic/molecular activities on material surfaces, non-invasively. The expression levels of TRPC1 were increased by liposomal transfection, whose effectiveness was evaluated by Western-blotting and single cell reverse transcription-polymerase chain reaction. RESULTS Ca(2+) influxes could be elicited by adding 1 mmol/L CaCl(2) to the test solution of HL-7702 cells. They were enhanced by addition of 20 micromol/L noradrenaline and inhibited by 100 micromol/L LaCl(3) (a non-selective Ca(2+) channel blocker); 5 micromol/L nifedipine did not induce any change. Overexpression of TRPC1 caused increased Ca(2+) influx. Five micromoles per liter nifedipine did not inhibit this elevation, whereas 100 micromol/L LaCl(3) did. CONCLUSION In HL-7702 cells, there is a type of TRPC1-dependent Ca(2+) channel, which could be detected via NMT and inhibited by La(3+).
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Affiliation(s)
- Zhen-Ya Zhang
- Department of General Surgery, Digestive Medical Center, the First Affiliated Hospital, Medical School, Tsinghua University, Beijing 100016, China
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Strahl T, Thorner J. Synthesis and function of membrane phosphoinositides in budding yeast, Saccharomyces cerevisiae. BIOCHIMICA ET BIOPHYSICA ACTA 2007; 1771:353-404. [PMID: 17382260 PMCID: PMC1868553 DOI: 10.1016/j.bbalip.2007.01.015] [Citation(s) in RCA: 231] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/06/2006] [Revised: 01/29/2007] [Accepted: 01/30/2007] [Indexed: 02/02/2023]
Abstract
It is now well appreciated that derivatives of phosphatidylinositol (PtdIns) are key regulators of many cellular processes in eukaryotes. Of particular interest are phosphoinositides (mono- and polyphosphorylated adducts to the inositol ring in PtdIns), which are located at the cytoplasmic face of cellular membranes. Phosphoinositides serve both a structural and a signaling role via their recruitment of proteins that contain phosphoinositide-binding domains. Phosphoinositides also have a role as precursors of several types of second messengers for certain intracellular signaling pathways. Realization of the importance of phosphoinositides has brought increased attention to characterization of the enzymes that regulate their synthesis, interconversion, and turnover. Here we review the current state of our knowledge about the properties and regulation of the ATP-dependent lipid kinases responsible for synthesis of phosphoinositides and also the additional temporal and spatial controls exerted by the phosphatases and a phospholipase that act on phosphoinositides in yeast.
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Affiliation(s)
- Thomas Strahl
- Divisions of Biochemistry & Molecular Biology and of Cell & Developmental Biology.Department of Molecular and Cell Biology, University of California, Berkeley, CA 94720 USA
| | - Jeremy Thorner
- Divisions of Biochemistry & Molecular Biology and of Cell & Developmental Biology.Department of Molecular and Cell Biology, University of California, Berkeley, CA 94720 USA
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12
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Folk P, Kmoníčková E, Krpejšová L, Strunecká A. 35S-labelled thiophosphorylated derivative of inositol trisphosphate. J Labelled Comp Radiopharm 2006. [DOI: 10.1002/jlcr.2580250713] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Exton JH. The roles of calcium and phosphoinositides in the mechanisms of alpha 1-adrenergic and other agonists. Rev Physiol Biochem Pharmacol 2005; 111:117-224. [PMID: 2906170 DOI: 10.1007/bfb0033873] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
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14
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Galvan DL, Mignery GA. Carboxyl-terminal sequences critical for inositol 1,4,5-trisphosphate receptor subunit assembly. J Biol Chem 2002; 277:48248-60. [PMID: 12377774 DOI: 10.1074/jbc.m209990200] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The inositol 1,4,5-trisphosphate receptor (InsP(3)R) is a tetrameric assembly of conserved subunits that each contains six transmembrane regions (TMRs) localized near the carboxyl terminus. Receptor subunit assembly into a tetramer appears to be a multideterminant process involving an additive contribution of membrane spanning helices and the short cytosolic carboxyl terminus (residues 2590-2749). Previous studies have shown that of the six membrane-spanning regions in each subunit, the 5th and 6th transmembrane regions, and the carboxyl terminus are strong determinants for assembly. The fifth and sixth TMRs contain numerous beta-branched amino acids that may participate in coiled/coil formation via putative leucine zipper motifs. InsP(3)R truncation mutants were expressed in COS-1 cells and analyzed by sucrose density gradient sedimentation and gel filtration for their ability to assemble. Chemical cross-linking with the homobifunctional reagents sDST or DMS of mammalian and bacterially expressed carboxyl-terminal containing receptor fragments reveals that sequences within the carboxyl terminus confer the formation of subunit dimers. A series of InsP(3) receptor carboxyl-terminal fragments and glutathione S-transferase (GST)/InsP(3)R chimeras were expressed in Escherichia coli and used in an in vitro assay to elucidate the minimal sequence responsible for association of the carboxyl termini into dimers. The results presented here indicate that this minimal sequence is approximately 30 residues in length and is localized between residues 2629 and 2654. These residues are highly conserved between the three InsP(3)R isoforms ( approximately 80% identity) as well as the ryanodine receptor ( approximately 40% identity) and suggest that a conserved assembly motif may exist between the two intracellular receptor families. We propose that assembly of the InsP(3) receptor to a tetramer involves intersubunit interactions mediated through both the membrane-spanning regions and residues 2629-2654 of the carboxyl terminus possibly through the formation of a dimer of dimers.
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Affiliation(s)
- Daniel L Galvan
- Department of Physiology, Stritch School of Medicine, Loyola University Chicago, Maywood, Illinois 60153, USA
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15
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Lin C, Widjaja J, Joseph SK. The interaction of calmodulin with alternatively spliced isoforms of the type-I inositol trisphosphate receptor. J Biol Chem 2000; 275:2305-11. [PMID: 10644679 DOI: 10.1074/jbc.275.4.2305] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
A 592-amino acid segment of the regulatory domain of the neuronal type-I inositol 1,4,5-trisphosphate receptor (IP(3)R) isoform (type-I long, amino acids1314-1905) and the corresponding 552-amino acid alternatively spliced form present in peripheral tissues (type-I short, amino acids 1693-1733 deleted) were expressed as glutathione S-transferase fusion proteins. These domains encompass a putative calmodulin (CaM) binding domain and two protein kinase A phosphorylation sites. Both long and short fusion proteins retained the ability to bind CaM in a Ca(2+)-dependent manner as measured by CaM-Sepharose chromatography or a dansyl-CaM fluorescence assay. Both assays indicated that the short fusion protein bound twice the amount of CaM than the long form at saturating concentrations of CaM. In addition, the binding of the short form to CaM-Sepharose was inhibited by phosphorylation with protein kinase A, whereas the binding of the long form was unaffected. Full-length cDNAs encoding type-I long, type-I short, and type-III IP(3)R isoforms were expressed in COS cells, and the Ca(2+) sensitivity of [(3)H]IP(3) binding to permeabilized cells was measured. The type-I long isoform was more sensitive to Ca(2+) inhibition (IC(50) = 0.55 microM) than the type-I short (IC(50) = 5.7 microM) or the type-III isoform (IC(50) = 3 microM). In agreement with studies on the fusion proteins, the full-length type-I short bound more CaM-Sepharose, and this binding was inhibited to a greater extent by protein kinase A phosphorylation than the type-I long IP(3)R. Although type-III IP(3)Rs did not bind directly to CaM-Sepharose, hetero-oligomers of type-I/III IP(3)Rs retained the ability to interact with CaM. We conclude that the deletion of the SII splice site in the type-I IP(3)R results in the differential regulation of the alternatively spliced isoforms by Ca(2+), CaM, and protein kinase A.
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Affiliation(s)
- C Lin
- Department of Pathology, Thomas Jefferson University School of Medicine, Philadelphia, Pennsylvania 19107, USA
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Maitra SR, Homan CS, Beuhler MC, Thode HC, Henry M. Alterations in hepatic gluconeogenesis, prostanoid, and intracellular calcium during sepsis. Acad Emerg Med 1999; 6:588-95. [PMID: 10386675 DOI: 10.1111/j.1553-2712.1999.tb00410.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
OBJECTIVE The metabolic alterations observed during sepsis may be associated with changes in local concentrations of intracellular calcium (Ca2+) and prostanoid synthesis in the liver. The authors studied hepatocyte intracellular Ca2+ and the release of glucose and prostanoid in an in-vivo murine liver perfusion model. METHODS Sepsis was induced in anesthetized, fasted rats by cecal ligation and puncture (CLP, n = 42). Hepatic glucose release was studied in control (n = 10) and CLP (n = 10) groups using a non-recirculating liver perfusion model with and without lactate as gluconeogenic substrate. Hepatocyte intracellular Ca2+ (n = 11) was measured using the selective indicator Fura-2 under basal and epinephrine (10(-5) M) stimulated conditions. 6-Keto-prostaglandin F1alpha (6-Keto) and thromboxane B2 (TxB2) were determined from liver perfusate by radioimmunassay (n = 11). Data were analyzed using t-tests and repeated-measures ANOVA. RESULTS Plasma glucose was significantly lower in CLP groups compared with controls (74.9+/-6.6 vs 115.7+/-4.6 mg/dL, p < 0.05). Plasma lactate was significantly higher in CLP vs controls (3.7+/-0.4 vs 1.4+/-0.1 mM, p < 0.05). Glucose release in isolated perfused livers was significantly lower in CLP vs controls (8.5 vs 16+/-1.2 microM/g/hr, p < 0.001). With the addition of lactate + pyruvate to the perfusate, glucose output in CLP livers was significantly lower following 5 (9.9+/-0.7 vs 17.7+/-1.1 microM/g/hr, p < 0.05) and 10 (11.9+/-1.2 vs 20.6+/-1.3 microM/g/hr, p < 0.001) minutes of perfusion. The basal level of intracellular calcium ([Ca2+]i) in CLP rats (460.1+/-91.6 nM) was significantly higher than in control rats (196.3+/-35.5 nM) (p < 0.05). A significant increase (p < 0.05) in [Ca2+]i occurred after the addition of epinephrine in hepatocytes in control (196.3+/-35.5 vs 331.8+/-41.4 nM) but not CLP (460.1+/-91.6 vs 489.4+/-105 nM) rats. 6-Keto was significantly lower in CLP compared with controls at 30 minutes (25.7+/-3.9 vs 33.4+/-5.5 pg/mL, p < 0.05), whereas TxB2 was not significantly altered (52.1+/-34.7 vs 87.5+/-43.2 pg/mL). CONCLUSION These results demonstrate that CLP sepsis is associated with an increase in hepatocyte intracellular free Ca2+ concentration along with attenuation of hormone-mediated Ca2+ mobilization and hepatic gluconeogenesis.
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Affiliation(s)
- S R Maitra
- Department of Emergency Medicine, University Medical, Center State University of New York Stony Brook 11794-7400, USA.
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Bokkala S, Joseph SK. Angiotensin II-induced down-regulation of inositol trisphosphate receptors in WB rat liver epithelial cells. Evidence for involvement of the proteasome pathway. J Biol Chem 1997; 272:12454-61. [PMID: 9139693 DOI: 10.1074/jbc.272.19.12454] [Citation(s) in RCA: 72] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Chronic stimulation of WB rat liver epithelial cells by angiotensin II (Ang II) resulted in the down-regulation of both type I and type III myo-inositol 1,4,5-trisphosphate receptors (IP3Rs). Stimulation with vasopressin, bradykinin, epidermal growth factor, or 12-O-tetradecanoylphorbol-13-acetate was without effect. Ang II-induced down-regulation of IP3Rs could be detected within 2 h and resulted in an inhibition of IP3-induced Ca2+ release from permeabilized cells. IP3R down-regulation was reversible, and both homo- and heterooligomers of IP3Rs were equally susceptible to Ang II-induced degradation. Chloroquine and NH4Cl increased the basal levels of IP3Rs by 2-fold, suggesting that the basal turnover of IP3Rs occurs via a lysosomal pathway. However, Ang II-induced degradation of IP3R was not affected by these inhibitors, suggesting that stimulated degradation of IP3Rs occurs via a non-lysosomal pathway. The cysteine protease and proteasomal inhibitor N-acetyl-Leu-Leu-norleucinal completely prevented Ang II-mediated down-regulation of IP3Rs, whereas the structural analog N-acetyl-Leu-Leu-methioninal was without effect. Lactacystin, a highly specific proteasome inhibitor, also blocked Ang II-mediated IP3R degradation. Stimulation with Ang II increased the amount of IP3R immunoprecipitated by anti-ubiquitin antibodies. We conclude that Ang II-stimulated IP3R degradation involves enhanced ubiquitination of the protein and degradation by the proteasome pathway.
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Affiliation(s)
- S Bokkala
- Department of Pathology, Thomas Jefferson University School of Medicine, Philadelphia, Pennsylvania 19107, USA
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Khan AA, Soloski MJ, Sharp AH, Schilling G, Sabatini DM, Li SH, Ross CA, Snyder SH. Lymphocyte apoptosis: mediation by increased type 3 inositol 1,4,5-trisphosphate receptor. Science 1996; 273:503-7. [PMID: 8662540 DOI: 10.1126/science.273.5274.503] [Citation(s) in RCA: 210] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
B and T lymphocytes undergoing apoptosis in response to anti-immunoglobulin M antibodies and dexamethasone, respectively, were found to have increased amounts of messenger RNA for the inositol 1,4,5-trisphosphate receptor (IP3R) and increased amounts of IP3R protein. Immunohistochemical analysis revealed that the augmented receptor population was localized to the plasma membrane. Type 3 IP3R (IP3R3) was selectively increased during apoptosis, with no enhancement of type 1 IP3R (IP3R1). Expression of IP3R3 antisense constructs in S49 T cells blocked dexamethasone-induced apoptosis, whereas IP3R3 sense, IP3R1 sense, or IP3R1 antisense control constructs did not block cell death. Thus, the increases in IP3R3 may be causally related to apoptosis.
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MESH Headings
- Amino Acid Sequence
- Animals
- Apoptosis
- B-Lymphocytes/cytology
- B-Lymphocytes/metabolism
- Base Sequence
- Calcium/metabolism
- Calcium Channels/genetics
- Calcium Channels/immunology
- Calcium Channels/metabolism
- Cell Line
- Cell Membrane/metabolism
- Cells, Cultured
- DNA, Antisense
- Dexamethasone/pharmacology
- Immunoblotting
- Inositol 1,4,5-Trisphosphate/metabolism
- Inositol 1,4,5-Trisphosphate Receptors
- Mice
- Molecular Sequence Data
- Receptors, Cytoplasmic and Nuclear/genetics
- Receptors, Cytoplasmic and Nuclear/immunology
- Receptors, Cytoplasmic and Nuclear/metabolism
- T-Lymphocytes/cytology
- T-Lymphocytes/metabolism
- Transfection
- Tumor Cells, Cultured
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Affiliation(s)
- A A Khan
- Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
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19
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Ward ME, Hussain SN. Effect of alpha-adrenoreceptor stimulation on the diaphragmatic oxygen delivery-consumption relationship. J Crit Care 1996; 11:19-26. [PMID: 8904280 DOI: 10.1016/s0883-9441(96)90016-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
PURPOSE In the vascularly isolated canine hemidiaphragm, we tested the hypothesis that alpha-adrenoreceptor stimulation may influence diaphragmatic function and O2 extraction during reductions in O2 delivery (QO2di). METHODS The diaphragm was perfused using a constant flow pump with blood diverted from the left femoral artery. QO2di was reduced in a stepwise fashion by progressive reductions in pump flow. The tension generated by the contracting diaphragm (3 Hz), the critical O2 delivery (QO2di,c) below which O2 consumption (VO2di) becomes dependent on O2 supply and the oxygen extraction ratio at this critical point (ERc) were assessed in two groups of animals. Phenylephrine (10(-5) mol/L) was infused into the phrenic artery in one group and saline was infused in another group. RESULTS In the contracting diaphragm, VO2di was higher in the phenylephrine infused group than in the control group (5.2 +/- 0.5 vs 2.11 +/- 0.3 mL/min/100 g). QO2di,c and ERc were also higher in the phenylephrine group than in the control group (6.16 +/- 0.43 vs 3.1 +/- 0.5 mL/min/100 g and 0.87 +/- 0.035 vs 0.63 +/- 0.05, respectively). In the resting diaphragm, VO2di was not significantly different between the two groups and no critical oxygen delivery could be identified in either group. CONCLUSIONS These results indicate that alpha-adrenoreceptor activation may increase the tension generated by the diaphragm as well as its oxygen consumption and oxygen extraction. Although this may be beneficial during moderate reductions in oxygen delivery, in more severe shock states, activation of these receptors by endogenous or exogenously administered catecholamines may hasten the development of delivery limitation of VO2di and compromise the ability to sustain ventilation.
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Affiliation(s)
- M E Ward
- Division of Critical Care Medicine, Royal Victoria Hospital, McGill University, Montreal, Quebec, Canada
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20
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Myers SI, Evans CT, Bartula L, Riva A, Kalley-Taylor B. Regulation of eicosanoid synthesis in fibroblasts from inflamed gallbladders. Mol Cell Endocrinol 1995; 115:29-39. [PMID: 8674862 DOI: 10.1016/0303-7207(95)03667-v] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Gallbladder cell cultures obtained from rabbits subjected to sham or 72 h of bile duct ligation (72 h BDL, cholecystitis model) were incubated with calcium ionophore (A23187), dibutyryl cAMP (cAMP), and phorbol 12,13-diacetate (phorbol) to determine the intracellular signal transduction mechanisms responsible for increased inflamed gallbladder eicosanoid synthesis. Incubation of sham and 72 h BDL cell cultures with A23187 or phorbol significantly increased, whereas cAMP decreased, release of 6-keto-PGF1 alpha, PGE2, thromboxane B2 (measured by enzyme immunoassay) in a dose-related manner. Seventy-two-hour BDL cell cultures contained a specific 2-fold increased level of prostacyclin synthase compared to sham cell cultures which was not altered by preincubation with A23187, phorbol or cAMP. These findings suggest that increased PGI2 release in the sham and inflamed cell cultures following A23187 and phorbol stimulation was mediated in part via the inositol triphosphate pathway and protein kinase C activation and was not associated with altered cyclooxygenase or prostacyclin synthase content.
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Affiliation(s)
- S I Myers
- Department of Surgery, University of Texas Southwestern Medical Center, Dallas, USA
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21
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Palmeira CM, Moreno AJ, Madeira VM. Effects of paraquat, dinoseb and 2,4-D on intracellular calcium and on vasopressin-induced calcium mobilization in isolated hepatocytes. Arch Toxicol 1995; 69:460-6. [PMID: 8526741 DOI: 10.1007/s002040050199] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The effects of the herbicides paraquat, dinoseb and 2,4-D on intracellular Ca2+ levels and on vasopressin-induced Ca2+ mobilization were investigated in intact isolated hepatocytes. Incubation of rat hepatocytes with paraquat (5 mM for 60 min) and dinoseb (10 microM) resulted in a time-dependent loss of viability by approximately 25%. Viability of cells treated with 2,4-D decreased significantly, dropping to about 20% at 10 mM and 60 min incubation. Exposure of hepatocytes to paraquat (1-10 mM) for 60 min had no effect on the basal level of [Ca2+]i. Additionally, exposure to paraquat had no effect on the magnitude and on the duration of the [Ca2+]i response to vasopressin. In the presence of 2,4-D (1-10 mM), basal [Ca2+]i increases as a function of herbicide concentration. The magnitude of the delta[Ca2+]i response decreases from 256 +/- 8 nM in control to 220 +/- 5 nM, at 10 mM 2,4-D. Exposure of hepatocytes to dinoseb (1-10 microM) had no effect on the basal level of [Ca2+]i. However, a strong concentration-dependent decrease in the magnitude of delta[Ca2+]i in response to vasopressin was noticed at 60 min incubation. Dinoseb markedly inhibited the stimulation of the production of inositol phosphates by vasopressin stimulus. The present study demonstrates that paraquat, 2,4-D and dinoseb cause cell death in hepatocytes by mechanisms not related to an early increase in [Ca2+]i. Additionally, it has been shown for the first time that dinoseb disturbs the transduction mechanism promoted by vasopressin by inhibiting the formation of IP3.
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Affiliation(s)
- C M Palmeira
- Department of Zoology, University of Coimbra, Portugal
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22
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Luminal communication between intracellular calcium stores modulated by GTP and the cytoskeleton. J Biol Chem 1994. [DOI: 10.1016/s0021-9258(17)34058-9] [Citation(s) in RCA: 66] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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Affiliation(s)
- R R Ruffolo
- SmithKline Beecham Pharmaceuticals, King of Prussia, Pennsylvania 19406-0939
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24
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Identification and characterization of the phosphatidylinositol-(4, 5)-bisphosphate 5-phosphatase in human platelets. J Biol Chem 1994. [DOI: 10.1016/s0021-9258(17)41875-8] [Citation(s) in RCA: 55] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
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Abstract
Major advances have been made in our understanding of the molecular structure and function of the alpha-adrenoceptors. Many new subtypes of the alpha-adrenoceptor have been identified recently through biochemical and pharmacological techniques and several of these receptors have been cloned and expressed in a variety of vector systems. Currently, at least seven subtypes of the alpha-adrenoceptor have been identified and the molecular structure and biochemical functions of these subtypes are beginning to be understood. The alpha-adrenoceptors belong to the super family of receptors that are coupled to guanine nucleotide regulatory proteins (G-proteins). A variety of G-proteins are involved in the coupling of the various alpha-adrenoceptor subtypes to intracellular second messenger systems, which ultimately produce the end-organ response. The mechanisms by which the alpha-adrenoceptor subtypes recognize different G-proteins, as well as the molecular interactions between receptors and G-proteins, are the topics of current research. Furthermore, the physiological and pathophysiological role that alpha-adrenoceptors play in homeostasis and in a variety of disease states is also being elucidated. These major advances made in alpha-adrenoceptor classification, molecular structure, physiologic function, second messenger systems and therapeutic relevance are the subject of this review.
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Affiliation(s)
- R R Ruffolo
- Department of Pharmacology, SmithKline Beecham Pharmaceuticals, King of Prussia, PA 19406
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26
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Parissenti AM, Su L, Riedel H. Reconstitution of protein kinase C alpha function by the protein kinase C beta-I carboxy terminus. Mol Cell Endocrinol 1993; 98:9-16. [PMID: 8143918 DOI: 10.1016/0303-7207(93)90230-h] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
The Ca(2+)- and phospholipid-dependent Ser/Thr kinase protein kinase C (PKC) plays important roles in the transduction of cellular signals. Various PKC isoforms exist in mammalian cells which share conserved and variable regions as defined by cDNA sequence comparisons. To test whether carboxyl (C) terminal sequences of distinct isoforms can complement each other to yield functional chimeric molecules, we have constructed a PKC chimera in which amino acids 595-672 at the C-terminus of bovine PKC alpha (a) were replaced with the corresponding C-terminal amino acids (598-671) of rat PKC beta-I (b) to yield the chimera alpha/beta-I (ab). The chimera was then characterized biochemically and functionally, and compared with the parental isoforms. Since structure/function analysis of PKC in mammalian experimental systems is complicated by multiple PKC isoforms and by cellular complexity, we stably introduced the PKC constructs into the yeast Saccharomyces cerevisiae, a simple, lower eukaryote with a short doubling time and well established molecular genetics. In yeast, the faithfully expressed PKCab chimera and normal PKC isoforms bound radiolabelled phorbol ester and were recognized on immunoblots by PKC-specific antibodies. The chimera phosphorylated substrate peptides in a PMA- and Ca(2+)-dependent manner, and, upon activation, increased the cell doubling time and the rate of Ca2+ uptake into cells. In addition, PKCab displayed characteristics distinct from normal PKCb, but virtually indistinguishable from normal PKCa. Our findings indicate the reconstitution of PKCa function by the PKCb carboxyl terminus.
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Affiliation(s)
- A M Parissenti
- Section on Molecular Biology, Joslin Diabetes Center, Boston, MA 02215
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27
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Morishita F, Shimada A, Fujimoto M, Katayama H, Yamada K. Inhibition of adenylate cyclase activity in the goldfish melanophore is mediated by ? 2-adrenoceptors and a pertussis toxin-sensitive GTP-binding protein. J Comp Physiol B 1993; 163:533-40. [DOI: 10.1007/bf00302111] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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28
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Renard-Rooney D, Hajnóczky G, Seitz M, Schneider T, Thomas A. Imaging of inositol 1,4,5-trisphosphate-induced Ca2+ fluxes in single permeabilized hepatocytes. Demonstration of both quantal and nonquantal patterns of Ca2+ release. J Biol Chem 1993. [DOI: 10.1016/s0021-9258(19)49505-7] [Citation(s) in RCA: 56] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
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29
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Calderwood SK, Stevenson MA, Price BD. Activation of phospholipase C by heat shock requires GTP analogs and is resistant to pertussis toxin. J Cell Physiol 1993; 156:153-9. [PMID: 8314854 DOI: 10.1002/jcp.1041560121] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
The heat shock response in mammals consists of a complex array of intracellular reactions initiated by stress, although its regulation is poorly understood. We have investigated the role of transmembrane signal transduction in the response, examining mechanisms involved in the activation of phospholipase C (PLC) by heat shock. In rodent fibroblasts permeabilized with digitonin, heat shock and receptor-mediated PLC activity exhibited a strict GTP analog dependency. This indicates that heat shock-mediated phospholipase activation, in common with receptor mediated stimulation, does not involve direct effects on the phospholipases and suggests the participation of GTP binding (G) proteins in the activation process. When cells were treated with the inhibitor pertussis toxin (PTX), the phospholipases retained their inducibility by heat shock, but became refractory to thrombin treatment, indicating that heat shock may influence PLC activity through a distinct population of G proteins compared to thrombin. The data seem to exclude a role for PTX sensitive G proteins in the production of IP3 after heating and suggest a pathway involving the direct thermal activation of the Gq class of G proteins, which are coupled to the PLC beta 1 isoform.
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Affiliation(s)
- S K Calderwood
- Dana-Farber Cancer Institute, Harvard Medical School, Boston, Massachusetts 02115
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30
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Panfoli I, Morelli A, Viarengo A, Orunesu M. Biochemical characterization of a phosphatidylinositol 4,5-bisphosphate-specific phospholipase C activity in gills and digestive gland of the marine mussel Mytilus galloprovincialis Lam. COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY. B, COMPARATIVE BIOCHEMISTRY 1993; 105:139-45. [PMID: 8389267 DOI: 10.1016/0305-0491(93)90180-d] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
1. Polyphosphoinositide-specific phosphodiesterase (phospholipase C, PLC) activity against phosphatidylinositol 4,5-bisphosphate, present in gill and digestive gland homogenates of mussel (Mytilus galloprovincialis Lam.), has been biochemically characterized. 2. The enzyme was strictly modulated by free calcium ion concentration in both tissues and maximally activated at 10(-5) M Ca2+ (19 +/- 4 and 11 +/- 2 nmol phosphatidylinositol 4,5-bisphosphate hydrolysed/min/mg of protein for gill and digestive gland PLC, respectively, at 19 degrees C). Optimum pH at 10(-5) M Ca2+ was around 7.0 in both cases. The Ca(2+)-stimulated PLC activity showed high specificity for PIP2; the KMa for PIP2 were 150 and 170 microM for the gills and digestive gland, respectively. 3. Good substrate dispersion was obtained in the presence of sodium deoxycholate; the concentration routinely used in the assay (0.08%) produced a 9-fold activation of both gill and digestive gland PLC, consistent with previous reports. 4. The possible biochemical and physiological role of the enzyme in mussel tissues is discussed.
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Affiliation(s)
- I Panfoli
- Istituto Policattedra di Chimica Biologica dell'Università, Genova, Italy
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31
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Abstract
Effect of polymyxin B (PMB, protein kinase C inhibitor) on estradiol-induced thymidine incorporation into uterine DNA was studied in ovariectomized rats. Administration of estradiol to ovariectomized rats enhanced thymidine incorporation to uterine DNA 15-fold. Pretreatment of rats with PMB 1 hour before the administration of estradiol had a dose-dependent inhibitory effect on estradiol induced response. PMB had no effect on the basal levels of thymidine incorporation. The inhibitory effect of PMB was also observed with prostaglandin F2 alpha (PGF2 alpha)-induced thymidine incorporation. Time-course experiments indicate that PMB was effective in alleviating estradiol-induced response when administered 1 hour before or 5 minutes after estradiol administration. However, PMB did not antagonize estradiol-induced response when administered at 2, 4, 8, and 12 hours after estradiol administration. Polymyxin E (PME), which differs from PMB by one conservative amino acid substitution in the ring structure and is devoid of PKC activation, did not decrease estradiol- or PGE2 alpha-enhanced thymidine incorporation. It is concluded that estradiol-induced protein kinase-C activation may play a role in the stimulation of thymidine incorporation into uterine DNA and that this effect occurs within the first 2 hours of estradiol administration.
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Affiliation(s)
- K Rajkumar
- Department of Obstetrics and Gynecology, University of Saskatchewan, Saskatoon, Canada
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Baffy G, Miyashita T, Williamson J, Reed J. Apoptosis induced by withdrawal of interleukin-3 (IL-3) from an IL-3-dependent hematopoietic cell line is associated with repartitioning of intracellular calcium and is blocked by enforced Bcl-2 oncoprotein production. J Biol Chem 1993. [DOI: 10.1016/s0021-9258(18)53280-4] [Citation(s) in RCA: 204] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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Kobayashi K, Shaver JK, Liang W, Siperstein AE, Duh QY, Clark OH. Increased phospholipase C activity in neoplastic thyroid membrane. Thyroid 1993; 3:25-9. [PMID: 8388752 DOI: 10.1089/thy.1993.3.25] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
The phospholipase C (PLC)-protein kinase C (PKC) signal transduction pathway appears to be important for cellular growth of many normal and neoplastic tissues. Because alterations in the thyroid-stimulating hormone (TSH) receptor-adenylate cyclase-protein kinase A system in some thyroid tumors do not correlate with tumor size, invasiveness, or metastatic potential, we studied the PLC activity in both normal and neoplastic thyroid tissues from 11 patients. Five of these patients had follicular adenomas and 6 had papillary carcinomas. An 8,000 x g membrane fraction and a 105,000 x g cytosol fraction were prepared from the normal and neoplastic human thyroid tissues. PLC hydrolyzes phosphatidylinositol, 4,5-diphosphate (PIP2) to diacylglycerol (DAG) and inositol 1,4,5-triphosphate (IP3). Phospholipase C activity was determined measuring the hydrolysis of [3H]-PIP2. The activity of PLC in the neoplastic thyroid tissue membrane fraction (20.91 +/- 2.28 nmol PIP2 hydrolyzed/mg protein/120 min) was higher than that in normal thyroid membrane (14.27 +/- 0.82) (p < 0.05). In contrast, PLC activity was similar in the neoplastic (16.12 +/- 0.86 nmol PIP2 hydrolyzed/mg protein/120 min) and normal (16.66 +/- 0.60) cytosol. There was no difference between PLC activity in the membrane fraction from adenomas (21.21 +/- 3.71 nmol PIP2 hydrolyzed/mg protein/120 min) when compared with thyroid carcinomas (20.67 +/- 3.14). Neoplastic thyroid membranes have greater PLC activity than that found in normal thyroid membranes from the same patients. Although PLC activity in benign and malignant thyroid membranes was similar, the increased PLC activity in thyroid neoplasms may be responsible for or contribute to the enhanced growth of some thyroid tumors.
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Affiliation(s)
- K Kobayashi
- UCSF/Mount Zion Medical Center San Francisco
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Baffy G, Yang L, Michalopoulos GK, Williamson JR. Hepatocyte growth factor induces calcium mobilization and inositol phosphate production in rat hepatocytes. J Cell Physiol 1992; 153:332-9. [PMID: 1429853 DOI: 10.1002/jcp.1041530213] [Citation(s) in RCA: 48] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The effects of hepatocyte growth factor (HGF) on intracellular Ca2+ mobilization were studied using fura-2-loaded single rat hepatocytes. Hepatocytes microperfused with different amounts of HGF responded with a rapid concentration-dependent rise in the cytosolic free Ca2+ concentration with a maximum increase of 142% at 80 ng/ml of HGF. The lag period of the Ca2+ response was decreased with increasing HGF concentrations, being 64 +/- 12 s, 42 +/- 6 s, and 14 +/- 2 s, respectively, with 8, 20, and 80 ng/ml of HGF. The detailed pattern of Ca2+ transients, however, was variable. Out of 16 cells tested using 20 ng/ml of HGF, 68% showed sustained oscillatory responses, whereas other cells showed a sustained increase in the cytosolic-free Ca2+ upon exposure to HGF, which was dependent on the presence of extracellular Ca2+. HGF also induced Ca2+ entry across the plasma membrane. Mobilization of Ca2+ by HGF was accompanied by a rapid accumulation of inositol 1,4,5-trisphosphate (Ins 1,4,5-P3). The effects of HGF and epidermal growth factor (EGF) were comparable and partly additive for Ins 1,4,5-P3 production and for the sustained phase of Ca2+ mobilization. Preincubation of cells with 10 microM of genistein to inhibit protein tyrosine kinases abolished the HGF-induced Ca2+ response and also inhibited HGF-induced Ins 1,4,5-P3 production in rat liver cells. These data indicate that early events in the signal transduction pathways mediated by HGF and EGF have in common the requirements for tyrosine kinase activity, Ins 1,4,5-P3 production, and Ca2+ mobilization.
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Affiliation(s)
- G Baffy
- Department of Biochemistry and Biophysics, University of Pennsylvania, Philadelphia 19104-6089
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35
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Hinkovska-Galchev V, Srivastava PN. Phosphatidylcholine and phosphatidylinositol-specific phospholipases C of bull and rabbit spermatozoa. Mol Reprod Dev 1992; 33:281-6. [PMID: 1333240 DOI: 10.1002/mrd.1080330308] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Acrosomal reaction is an essential prerequisite to fertilization. The changes in lipid composition of sperm membranes cause fusion of the plasma and outer acrosomal membranes that results in the exocytosis of acrosomal contents. We report that both bull and rabbit spermatozoa contain a phosphatidylcholine-specific phospholipase C (PC-PLC) that hydrolyzes L-alpha-dipalmitoyl-(choline-methyl-14C-153.0 Ci/mmol and a phosphatidylinositol-specific phospholipase C (PI-PLC) that hydrolyzes L-alpha-(Myo-Inositol-2-3H (N)-5.2 Ci mmol. PI-PLC from bull sperm acrosome has been purified 568 x fold with a specific activity 6.25 +/- 0.6 nmol/min/mg protein, km 0.004 mM, and Vmax 12 nmol/min/mg protein. Both enzymes had optimum at pH 7.5. The activity of PC-PLC remained unaffected by varying concentrations of Ca2+, whereas PI-PLC activity was significantly increased. The bulk of PI-PLC was found to be associated with inner acrosomal membrane of bull and rabbit sperm, while PC-PLC was found in the outer acrosomal membranes in the bull sperm and the plasma membrane of the rabbit sperm. Both enzymes are compartmentalized in sperm cell.
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36
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Abstract
This study was undertaken to investigate the role of endothelium in the modulation of vascular responses to bradykinin and to elucidate the receptor types and mechanism of action of bradykinin in isolated basilar artery. The results showed a contractile response to bradykinin in basilar artery. This contractile response to bradykinin was partially modulated by endothelium in a dose-dependent manner. In addition, both des-Arg9-[Leu8]bradykinin and [d-Arg0,Hyp3,Thi5,8,D-Phe7]bradykinin significantly antagonized the responses to bradykinin. However, the blocking effect and the apparent affinity of [d-Arg0,Hyp3,Thi5,8,D-Phe7]bradykinin (pA2 = 9.6 +/- 0.4) were greater than those with des-Arg9-[Leu8]bradykinin (pA.2 = 7.8 +/- 0.3). These results suggest that two apparently distinct types of BK receptors may exist in basilar arteries. Furthermore, the contractile response to bradykinin in basilar artery was significantly inhibited by 2-nitro-4-carboxyphenyl-N,N-diphenylcarbamate (10(-5) M), H-7 (10(-5) M) and TMB-8 (10(-5) M), but not by indomethacin (10(-5) M) or nordihydroquariaretic acid (10(-5) M). On the other hand, nifedipine, Ca(2+)-free medium, EGTA and Ca(2+)-free medium/EGTA significantly reduced the bradykinin-induced contraction, indicating that part of the contractile response of basilar artery to bradykinin is dependent on extracellular Ca2+. In conclusion, the mechanism of the contractile responses to bradykinin in basilar artery may involve increased intracellular Ca2+ levels acting on the BK1 and BK2 receptor, followed by activation of the phosphoinositide pathway and receptor-mediated Ca2+ channel.
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Affiliation(s)
- M H Yen
- Department of Pharmacology, National Defense Medical Center, Tapei, Taiwan
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37
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Lin HY, Davis PJ, Thacore HR. Production of human interferon-beta by Sendai virus and poly(rI).poly(rC): inhibition by neomycin. JOURNAL OF INTERFERON RESEARCH 1991; 11:365-9. [PMID: 1666117 DOI: 10.1089/jir.1991.11.365] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Neomycin inhibits the production of interferon-beta (IFN-beta) in human fibroblast cells in response to Sendai virus or to poly(rI).poly(rC) in a concentration-dependent manner, and to the greatest extent effective when added prior to or up to 2 h after induction. This inhibitory effect is negated when the protein kinase C activator, SC-9, is present during IFN-beta production in response to poly(rI).poly(rC), but not in response to Sendai virus. These results suggest that in human cells both virus and poly(rI).poly(rC) utilize an early neomycin-sensitive signal transduction step for the production of IFN-beta; because neomycin binds specific phosphatidylinositol phosphates, both of these inducers very likely require hydrolysis of these phosphates.
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Affiliation(s)
- H Y Lin
- Department of Microbiology, School of Medicine and Biomedical Sciences, State University of New York, Buffalo
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38
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Falsafi R, Tatakis DN, Hagel-Bradway S, Dziak R. Effects of inositol trisphosphate on calcium mobilization in bone cells. Calcif Tissue Int 1991; 49:333-9. [PMID: 1782574 DOI: 10.1007/bf02556256] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The effect of inositol 1,4,5 trisphosphate (IP3) on calcium mobilization was studied in human osteosarcoma lines, Saos-2 and G292, as well as isolated rat osteoblastic and osteoclastic cells. Cells were permeabilized with saponin and calcium mobilization was studied with the fluorescent dye, fura-2 in a recording spectrofluorometer. IP3 (10 microM) increased calcium release in all cell types studied. The effect was dependent on ATP and occurred in the presence of mitochondrial inhibitors. The effect was not seen with inositol 1-phosphate (IP) or inositol 1,4-diphosphate (IP2). Inositol 1,3,4,5 tetrakisphosphate (IP4) appeared to elicit a decrease in the calcium released. Depletion of the intracellular pool with the calcium ionophore, ionomycin, as well as incubation with the inhibitor of intracellular calcium mobilization, TMB-8, obliterated the IP3 effect. The results are consistent with the hypothesis that increases in IP3 can cause a rapid elevation of bone cell cytosolic calcium.
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Affiliation(s)
- R Falsafi
- Department of Oral Biology, School of Dental Medicine, State University of New York, Buffalo 14214
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39
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Conricode KM, Ochs RS. Vasopressin stimulates pyruvate utilization through a Ca(2+)-dependent mechanism and lactate formation by a protein kinase C-dependent mechanism in isolated rat hepatocytes. BIOCHIMICA ET BIOPHYSICA ACTA 1991; 1095:161-8. [PMID: 1932135 DOI: 10.1016/0167-4889(91)90079-d] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Vasopressin stimulates lactate production by hepatocytes from fed rats, an effect which has been attributed exclusively to Ca2+ activation of glycogenolysis. We provide evidence here for two further actions of vasopressin which affect lactate formation by rat hepatocytes. In the presence of 50 mM glucose, vasopressin inhibited lactate production by hepatocytes. The inhibition was relieved by the presence of alpha-cyano-4-hydroxycinnamate (alpha-CHC), which blocks mitochondrial pyruvate transport. This suggests that vasopressin stimulates pyruvate utilization in the presence of a high concentration of glucose. Epidermal growth factor (EGF), which also increases lactate formation by hepatocytes, did not similarly decrease lactate accumulation in the presence of high glucose, suggesting no stimulation of lactate and pyruvate utilization by this hormone. In cells depleted of Ca2+, vasopressin also stimulated lactate formation. Although vasopressin did not cause the apparent translocation of protein kinase C between cell spaces, phospholipase C treatment of hepatocytes did duplicate vasopressin stimulation of lactate formation, provided fatty acid oxidation was suppressed by the simultaneous presence of the inhibitor palmixorate. We conclude that three actions of vasopressin affect lactate and pyruvate formation: the calcium-linked activations of glycogenolysis and mitochondrial pyruvate utilization, and a stimulation of glycolysis likely mediated by protein kinase C.
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Affiliation(s)
- K M Conricode
- Department of Nutrition, Case Western Reserve University, Mt. Sinai Medical Center, Cleveland, OH 44106-4198
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40
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Bazotte RB, Pereira B, Higham S, Shoshan-Barmatz V, Kraus-Friedmann N. Effects of ryanodine on calcium sequestration in the rat liver. Biochem Pharmacol 1991; 42:1799-803. [PMID: 1656999 DOI: 10.1016/0006-2952(91)90518-a] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Ryanodine, a highly toxic alkaloid known to react specifically with the Ca2+ release channels in sarcoplasmic reticulum (SR), was employed to study Ca2+ sequestration in the liver. Ryanodine at a 200 microM concentration increased cytosolic free Ca2+ levels and phosphorylase a activity in isolated hepatocytes. These effects may involve microsomal Ca2+ sequestration, because ryanodine, in the presence of inhibitors of mitochondrial Ca2+ uptake, at concentrations of 1 nM, 1 microM, 50 microM and 100 microM decreased 45Ca2+ retention in permeabilized hepatocytes. This inhibition of Ca2+ retention by ryanodine was not due to inhibition of the microsomal Ca(2+)-ATPase. Dantrolene, a compound shown previously to inhibit ryanodine binding in the liver, also decreased 45Ca2+ retention in permeabilized hepatocytes, and activated phosphorylase a. These results show that ryanodine administration alters calcium sequestration in liver. The possibility of the existence of a ryanodine-sensitive Ca(2+)-release channel in liver is discussed.
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Affiliation(s)
- R B Bazotte
- Department of Physiology and Cell Biology, University of Texas Medical School, Houston 77225
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41
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Kawanishi T, Nieminen A, Herman B, Lemasters J. Suppression of Ca2+ oscillations in cultured rat hepatocytes by chemical hypoxia. J Biol Chem 1991. [DOI: 10.1016/s0021-9258(18)54891-2] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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42
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Hansen C, Yang L, Williamson J. Mechanisms of receptor-mediated Ca2+ signaling in rat hepatocytes. J Biol Chem 1991. [DOI: 10.1016/s0021-9258(18)55101-2] [Citation(s) in RCA: 48] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
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43
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Putney JW, Bird GS, Horstman DA, Hughes AR, Menniti FS, Nogimori K, Obie J, Oliver KG, Sugiya H, Takemura H. Role of inositol phosphates in the actions of substance P on NK1 receptors in exocrine gland cells. Ann N Y Acad Sci 1991; 632:94-102. [PMID: 1719914 DOI: 10.1111/j.1749-6632.1991.tb33097.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Affiliation(s)
- J W Putney
- Calcium Regulation Section, National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina 27709
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44
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Islam MS, Nilsson T, Rorsman P, Berggren PO. Interaction with the inositol 1,4,5-trisphosphate receptor promotes Ca2+ sequestration in permeabilised insulin-secreting cells. FEBS Lett 1991; 288:27-9. [PMID: 1652478 DOI: 10.1016/0014-5793(91)80995-f] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Electropermeabilised insulin-secreting RINm5F cells sequestered Ca2+, resulting in a steady-state level of the ambient free Ca2+ concentration corresponding to 723 +/- 127 nM (mean +/- SEM, n = 10), as monitored by a Ca(2+)-selective minielectrode. Inositol 1,4,5-trisphosphate (Ins(1,4,5)P3) promoted a rapid and pronounced release of Ca2+. This Ca2+ was resequestered and a new steady-state Ca2+ level was attained, which was always lower (460 +/- 102 nM, n = 10, P less than 0.001) than the steady-state Ca2+ level maintained before the addition of Ins(1,4,5)P3. Whereas the initial reuptake of Ca2+ subsequent to Ins(1,4,5)P3 stimulation was relatively slow, the later part of reuptake was fast as compared to the reuptake phases of a pulse addition of extraneous Ca2+. In the latter case the uptake of Ca2+ resulted in a steady-state level similar to that found in the absence of Ins(1,4,5)P3. Addition of Ins(1,4,5)P3 under this condition resulted in a further Ca2+ uptake and thus a lower steady-state Ca2+ level. Heparin, which binds to the Ins(1,4,5)P3 receptor, also lowered the steady-state free Ca2+ concentration. In contrast to Ins(1,4,5)P3, inositol 1,3,4,5-tetrakisphosphate was without effect on Ca2+ sequestration. These findings are consistent with the presence of a high-affinity Ins(1,4,5)P3 receptor promoting continuous release of Ca2+ under basal conditions and/or the Ins(1,4,5)P3 receptor being actively involved in Ca2+ sequestration.
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Affiliation(s)
- M S Islam
- Rolf Luft Center for Diabetes Research, Department of Endocrinology, Karolinska Institute, Karolinska Hospital, Stockholm, Sweden
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45
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Tokura Y, Edelson RL, Gasparro FP. Formation and removal of 8-MOP-DNA photoadducts in keratinocytes: effects of calcium concentration and retinoids. J Invest Dermatol 1991; 96:942-9. [PMID: 2045683 DOI: 10.1111/1523-1747.ep12475675] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
8-methoxypsoralen (8-MOP)-DNA photoadducts were quantified in freshly isolated human and murine keratinocytes and cultured keratinocyte cell lines after in vitro treatment with 8-MOP (1-200 ng/ml) and ultraviolet A (UVA; 0.2-24.0 J/cm2). Greater doses of 8-MOP and UVA led to proportionately greater numbers of photoadducts, with a dose reciprocity relationship between the amounts of 8-MOP and UVA. No significant difference in photoadduct formation was observed between basal and differentiated cells. However, the transformed keratinocyte cell lines showed fewer photoadducts than did normal keratinocytes, which appeared to be correlated with the finding that the adduct formation was inhibited in normal keratinocytes cultured with phorbol 12-myristate 13-acetate, because this agent leads to epidermal hyperproliferation. In viable keratinocytes that were treated with a sublethal dose of 8-MOP and UVA (15 ng/ml and 1 J/cm2, respectively), 54% of photoadducts formed were removed over a 20-h period. Adduct removal depended on the calcium concentration in the media; cells cultured in standard high calcium levels showed a higher removal rate than those cultured in low-calcium media. The addition of retinoids (etretinate, acitretin, and 13-cis retinoic acid) to the culture induced 55 to 80% of suppression of the adduct removal. The calcium ionophore A23187 partially restored the suppression of photoadduct removal induced by retinoids. The present studies suggest that calcium performs an important role in the photoadduct removal and raise the possibility that the synergism of systemic retinoids and psoralen plus UVA photochemotherapy relates to the former's inhibition of repair of 8-MOP photoadducts in DNA.
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Affiliation(s)
- Y Tokura
- Department of Dermatology, Yale University School of Medicine, New Haven, CT 06510-8059
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46
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Koshiyama H, Tashjian AH. Evidence for multiple intracellular calcium pools in GH4C1 cells: investigations using thapsigargin. Biochem Biophys Res Commun 1991; 177:551-8. [PMID: 1645964 DOI: 10.1016/0006-291x(91)92019-g] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The actions of thapsigargin (Tg), a plant sesquiterpene lactone, on Ca2+ homeostasis were investigated in digitonin-permeabilized GH4C1 rat pituitary cells. Tg (1 microM) caused a rapid and sustained increase in ambient Ca2+ concentration [( Ca2+]) and inhibited the rise in [Ca2+] induced by subsequent addition of TRH (100 nM), inositol 1,4,5-trisphosphate (IP3, 10 microM), or the nonhydrolyzable GTP analogue guanosine 5'-0-(3-thiotriphosphate) (GTP gamma S, 10 microM). However, neither IP3 nor GTP gamma S pretreatment, which themselves release sequestered Ca2+, prevented the Ca2+ accumulation induced by Tg. Pretreatment with heparin (100 micrograms/ml, 10 min), an IP3 receptor antagonist, did not affect Ca2+ accumulation induced by Tg, although it abolished the rise in [Ca2+] induced by IP3. The ability of Tg to increase [Ca2+] was dependent on added ATP. We conclude that, in GH4C1 cells, Tg acts, in part, on TRH-, IP3- and GTP gamma S-sensitive Ca2+ pools; however, Tg also acts on an ATP-dependent pool of intracellular Ca2+ which is not sensitive to TRH, IP3 or GTP gamma S, indicating a complexity of intracellular Ca2+ pools not previously appreciated in these cells.
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Affiliation(s)
- H Koshiyama
- Laboratory of Toxicology, Harvard School of Public Health, Boston, MA
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47
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Seishima M, Kudo Y, Nagao S, Mori S, Nozawa Y. Alterations in intracellular calcium transients of fibroblasts from progressive systemic sclerotic patients: a digital imaging microscopic study. Arch Dermatol Res 1991; 283:96-9. [PMID: 2069418 DOI: 10.1007/bf00371616] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Intracellular Ca2+ concentrations ([Ca2+]i) in cultured skin fibroblasts from normal subjects and progressive systemic sclerosis (PSS) patients were determined by using Fura-2 and fluorescent videomicroscopy. With the exception of fibroblasts from one PSS patient showing a higher [Ca2+]i, no significant difference was observed in resting [Ca2+]i between the two groups of fibroblasts. Bradykinin (BK) (10 microM) induced a transient [Ca2+]i increase in normal fibroblasts, whereas the BK-induced [Ca2+]i increase was reduced or not detectable in PSS fibroblasts. Removal of extracellular Ca2+ did not eliminate the BK-induced [Ca2+]i increase in normal fibroblasts. These findings suggest that BK stimulates Ca2+ release from intracellular stores in human fibroblasts, and also that the BK-mediated Ca2+ release is impaired in PSS fibroblasts.
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Affiliation(s)
- M Seishima
- Department of Dermatology, Gifu University School of Medicine, Japan
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48
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Abstract
Oncogenes are genes whose expression has been associated with malignant transformation of cells in tissue culture and with neoplastic changein vivo(Bishop, 1987). Much of the current understanding of their nature and action has stemmed from work, over the past 20 years, on tumour viruses (Temin, 1971; Rapp, 1983). One group of tumour viruses, the retroviruses, are unique in possessing an enzyme, reverse transcriptase, which transcribes to the cell DNA a copy of the viral RNA genome (Marks, 1987). After the discovery of viral oncogenes, such DNA copies were used as probes in hybridisation studies (Stehelinet al, 1976; Frankel & Fischinger, 1976). These probes, capable of annealing to complementary DNA sequences, revealed the existence of the latter in normal, unaffected cells (Willecke & Schäfer, 1984). These sequences, called cellular or proto-oncogenes, exist in a wide range of eukaryotic organisms, from yeast to man.
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Affiliation(s)
- J Leach
- Maudsley Hospital, Denmark Hill, London
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49
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Gonzales RA, Crews FT. Chronic ethanol inhibits receptor-stimulated phosphoinositide hydrolysis in rat liver slices. Alcohol 1991; 8:131-6. [PMID: 1648364 DOI: 10.1016/0741-8329(91)91321-r] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The effects of chronic ethanol feeding on norepinephrine (NE)- and arginine-vasopressin (AVP)-stimulated phosphoinositide (PI) hydrolysis in rat liver slices was determined. The maximum NE-stimulated PI response was significantly reduced by 40% in liver slices from 8-month-old rats which had been treated for 5 months with a liquid diet containing ethanol compared to pair-fed controls. The maximum AVP-stimulated PI response was decreased by 39% in liver slices from the ethanol-fed rats compared to control. EC50 values for NE- and AVP-stimulated PI hydrolysis in liver slices were not affected by the chronic ethanol treatment. Similar reductions in the maximal NE- and AVP-stimulated PI hydrolysis (28% and 27%, respectively) were found in 22-month-old rats which had been maintained on an ethanol containing diet for 5 months compared to pair-fed controls. The binding of [3H]prazosin and [3H]AVP to liver plasma membranes from 8-month-old ethanol-fed rats was not significantly different from binding to liver membranes from sucrose-fed controls. Our data suggest that chronic ethanol ingestion may lead to a reduction in PI-linked signal transduction in liver.
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Affiliation(s)
- R A Gonzales
- Department of Pharmacology, University of Texas, Austin 78712
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50
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Huang HM, Toral-Barza L, Gibson GE. Interactions between inositol phosphates and cytosolic free calcium following bradykinin stimulation in cultured human skin fibroblasts. BIOCHIMICA ET BIOPHYSICA ACTA 1991; 1091:409-16. [PMID: 2001422 DOI: 10.1016/0167-4889(91)90208-f] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
The inositol triphosphate (IP3) that results from hydrolysis of phosphatidylinositol 4,5-bisphosphate (PIP2) is generally accepted to be responsible for the mobilization of intracellular calcium. However, some studies suggest that low concentrations of agonists elevate cytosolic free calcium concentration ([Ca2+]i) without IP3 formation. Thus, in the present studies, a comparison of the temporal response of inositol phosphates (IP3, IP2 and IP) and [Ca2+]i to a wide range of bradykinin concentrations was used to examine the relation of these two signal transduction events in cultured human skin fibroblasts (GM3652). In addition, the effects of alterations in internal or external calcium on the response of these second messengers to bradykinin were determined. Bradykinin stimulated accumulation of inositol phosphates and a rise of [Ca2+]i in a time- and dose-dependent manner. Decreasing the bradykinin concentration from 1 microM to 0.1 microM increased the time until the IP3 peak, and when the bradykinin concentration was reduced to 0.01 microM IP3 was not detected. [Ca2+]i was examined under parallel conditions. As the bradykinin concentration was reduced from 1 microM to 0.01 microM, the time to reach the peak of [Ca2+]i increased progressively, but the magnitude of the peak was unaltered. These two second messengers were variably dependent on external calcium. Although the bradykinin-stimulated initial spike of [Ca2+]i did not depend on extracellular calcium, the subsequent sustained levels of [Ca2+]i were abolished in calcium free medium. The bradykinin-stimulated inositol phosphate formation was not dependent on the extracellular calcium nor on the elevation of [Ca2+]i that was produced with Br-A23187. These results demonstrate that bradykinin-induced IP3 formation can be independent of [Ca2+]i and of external calcium, whereas changes in [Ca2+]i are partially dependent on external calcium.
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Affiliation(s)
- H M Huang
- Cornell University Medical College, Burke Rehabilitation Center, White Plains, NY 10605
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