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Cross-linking of the endolysosomal system reveals potential flotillin structures and cargo. Nat Commun 2022; 13:6212. [PMID: 36266287 PMCID: PMC9584938 DOI: 10.1038/s41467-022-33951-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2022] [Accepted: 10/06/2022] [Indexed: 12/24/2022] Open
Abstract
Lysosomes are well-established as the main cellular organelles for the degradation of macromolecules and emerging as regulatory centers of metabolism. They are of crucial importance for cellular homeostasis, which is exemplified by a plethora of disorders related to alterations in lysosomal function. In this context, protein complexes play a decisive role, regulating not only metabolic lysosomal processes but also lysosome biogenesis, transport, and interaction with other organelles. Using cross-linking mass spectrometry, we analyze lysosomes and early endosomes. Based on the identification of 5376 cross-links, we investigate protein-protein interactions and structures of lysosome- and endosome-related proteins. In particular, we present evidence for a tetrameric assembly of the lysosomal hydrolase PPT1 and a heterodimeric structure of FLOT1/FLOT2 at lysosomes and early endosomes. For FLOT1-/FLOT2-positive early endosomes, we identify >300 putative cargo proteins and confirm eleven substrates for flotillin-dependent endocytosis, including the latrophilin family of adhesion G protein-coupled receptors.
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Tennakoon M, Senarath K, Kankanamge D, Ratnayake K, Wijayaratna D, Olupothage K, Ubeysinghe S, Martins-Cannavino K, Hébert TE, Karunarathne A. Subtype-dependent regulation of Gβγ signalling. Cell Signal 2021; 82:109947. [PMID: 33582184 PMCID: PMC8026654 DOI: 10.1016/j.cellsig.2021.109947] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2020] [Revised: 02/01/2021] [Accepted: 02/02/2021] [Indexed: 01/04/2023]
Abstract
G protein-coupled receptors (GPCRs) transmit information to the cell interior by transducing external signals to heterotrimeric G protein subunits, Gα and Gβγ subunits, localized on the inner leaflet of the plasma membrane. Though the initial focus was mainly on Gα-mediated events, Gβγ subunits were later identified as major contributors to GPCR-G protein signalling. A broad functional array of Gβγ signalling has recently been attributed to Gβ and Gγ subtype diversity, comprising 5 Gβ and 12 Gγ subtypes, respectively. In addition to displaying selectivity towards each other to form the Gβγ dimer, numerous studies have identified preferences of distinct Gβγ combinations for specific GPCRs, Gα subtypes and effector molecules. Importantly, Gβ and Gγ subtype-dependent regulation of downstream effectors, representing a diverse range of signalling pathways and physiological functions have been found. Here, we review the literature on the repercussions of Gβ and Gγ subtype diversity on direct and indirect regulation of GPCR/G protein signalling events and their physiological outcomes. Our discussion additionally provides perspective in understanding the intricacies underlying molecular regulation of subtype-specific roles of Gβγ signalling and associated diseases.
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Affiliation(s)
- Mithila Tennakoon
- Department of Chemistry and Biochemistry, The University of Toledo, Toledo, OH 43606, USA
| | - Kanishka Senarath
- Genetics and Molecular Biology Unit, University of Sri Jayewardenepura, Nugegoda, Sri Lanka
| | - Dinesh Kankanamge
- Department of Chemistry and Biochemistry, The University of Toledo, Toledo, OH 43606, USA
| | - Kasun Ratnayake
- Department of Chemistry and Biochemistry, The University of Toledo, Toledo, OH 43606, USA; Department of Pharmacology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Dhanushan Wijayaratna
- Department of Chemistry and Biochemistry, The University of Toledo, Toledo, OH 43606, USA
| | - Koshala Olupothage
- Department of Chemistry and Biochemistry, The University of Toledo, Toledo, OH 43606, USA
| | - Sithurandi Ubeysinghe
- Department of Chemistry and Biochemistry, The University of Toledo, Toledo, OH 43606, USA
| | | | - Terence E Hébert
- Department of Pharmacology and Therapeutics, McGill University, Montréal, QC H3G 1Y6, Canada.
| | - Ajith Karunarathne
- Department of Chemistry and Biochemistry, The University of Toledo, Toledo, OH 43606, USA.
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Malerba N, De Nittis P, Merla G. The Emerging Role of Gβ Subunits in Human Genetic Diseases. Cells 2019; 8:E1567. [PMID: 31817184 PMCID: PMC6952978 DOI: 10.3390/cells8121567] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2019] [Revised: 11/23/2019] [Accepted: 11/29/2019] [Indexed: 12/20/2022] Open
Abstract
Environmental stimuli are perceived and transduced inside the cell through the activation of signaling pathways. One common type of cell signaling transduction network is initiated by G-proteins. G-proteins are activated by G-protein-coupled receptors (GPCRs) and transmit signals from hormones, neurotransmitters, and other signaling factors, thus controlling a number of biological processes that include synaptic transmission, visual photoreception, hormone and growth factors release, regulation of cell contraction and migration, as well as cell growth and differentiation. G-proteins mainly act as heterotrimeric complexes, composed of alpha, beta, and gamma subunits. In the last few years, whole exome sequencing and biochemical studies have shown causality of disease-causing variants in genes encoding G-proteins and human genetic diseases. This review focuses on the G-protein β subunits and their emerging role in the etiology of genetically inherited rare diseases in humans.
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Affiliation(s)
- Natascia Malerba
- Division of Medical Genetics Unit, IRCCS Casa Sollievo della Sofferenza, Viale Cappuccini, 71013 San Giovanni Rotondo (FG), Italy;
| | - Pasquelena De Nittis
- Center for Integrative Genomics, University of Lausanne, CH-1015 Lausanne, Switzerland;
| | - Giuseppe Merla
- Division of Medical Genetics Unit, IRCCS Casa Sollievo della Sofferenza, Viale Cappuccini, 71013 San Giovanni Rotondo (FG), Italy;
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Wu F, Gao F, He S, Xiao Y. Identification of hub genes in chronically hypoxic myocardium using bioinformatics analysis. Mol Med Rep 2019; 19:3871-3881. [PMID: 30864710 PMCID: PMC6472133 DOI: 10.3892/mmr.2019.10001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2018] [Accepted: 12/02/2018] [Indexed: 11/05/2022] Open
Abstract
Chronic hypoxia can be observed in the heart under physiological or pathophysiological states, including embryonic development or cyanotic congenital heart disease. The aim of the present study was to examine gene expression profiles of chronically hypoxic myocardium and to explore the pathophysiological mechanisms by which the heart adapts to chronic hypoxia. Raw data from the next-generation sequencing data set GSE36761 were downloaded from the Gene Expression Omnibus database. The data set comprised 30 specimens, including 8 healthy myocardia and 22 tetralogy of Fallot (TOF) congenital cardiac malformations; only 7 original data sets of healthy myocardia were obtained, and 5/22 TOFs were excluded. Gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses of differentially expressed genes (DEGs) were performed. Furthermore, network analysis of DEGs using Cytoscape software based on protein-protein interaction (PPI) data was also conducted. A total of 1,260 DEGs were selected, of which 926 DEGs were enriched in 83 GO biological process terms, including extracellular matrix organization, regeneration and monocyte chemotaxis. Furthermore, 406 DEGs were enriched in 13 KEGG pathways, including cytokine-cytokine receptor interaction, focal adhesion and apoptosis. PPI network analysis indicated that six hub genes with correlated degree scores >25 among nodes were identified, including G protein subunit β4, C-C motif chemokine receptor (CCR)1, CCR2, platelet factor 4, catenin β1 and Jun proto-oncogene (JUN). Of these, JUN was enriched in GO terms of regeneration and neuron projection regeneration, and in KEGG pathways of focal adhesion, apoptosis and Chagas disease (American trypanosomiasis). The present bioinformatics analysis of these DEGs and hub genes may provide a molecular insight to the role of diverse genes in the pathophysiology of chronically hypoxic myocardium and in myocardial adaptation to chronic hypoxia.
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Affiliation(s)
- Fan Wu
- Department of Cardiovascular Surgery, Xinqiao Hospital, Army Medical University, Chongqing 400037, P.R. China
| | - Feng Gao
- Department of Cardiovascular Surgery, Chengdu Military General Hospital, Chengdu, Sichuan 610083, P.R. China
| | - Siyi He
- Department of Cardiovascular Surgery, Chengdu Military General Hospital, Chengdu, Sichuan 610083, P.R. China
| | - Yingbin Xiao
- Department of Cardiovascular Surgery, Xinqiao Hospital, Army Medical University, Chongqing 400037, P.R. China
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Li X, Carreria MB, Witonsky KF, Zeric T, Lofaro OM, Bossert JM, Zhang J, Surjono F, Richie CT, Harvey BK, Son H, Cowan CW, Nestler EJ, Shaham Y. Role of Dorsal Striatum Histone Deacetylase 5 in Incubation of Methamphetamine Craving. Biol Psychiatry 2018; 84:213-222. [PMID: 29397902 PMCID: PMC6026084 DOI: 10.1016/j.biopsych.2017.12.008] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/29/2017] [Revised: 11/28/2017] [Accepted: 12/08/2017] [Indexed: 12/12/2022]
Abstract
BACKGROUND Methamphetamine (meth) seeking progressively increases after withdrawal (incubation of meth craving). We previously demonstrated an association between histone deacetylase 5 (HDAC5) gene expression in the rat dorsal striatum and incubation of meth craving. Here we used viral constructs to study the causal role of dorsal striatum HDAC5 in this incubation. METHODS In experiment 1 (overexpression), we injected an adeno-associated virus bilaterally into dorsal striatum to express either green fluorescent protein (control) or a mutant form of HDAC5, which strongly localized to the nucleus. After training rats to self-administer meth (10 days, 9 hours/day), we tested the rats for relapse to meth seeking on withdrawal days 2 and 30. In experiment 2 (knockdown), we injected an adeno-associated virus bilaterally into the dorsal striatum to express a short hairpin RNA either against luciferase (control) or against HDAC5. After training rats to self-administer meth, we tested the rats for relapse on withdrawal days 2 and 30. We also measured gene expression of other HDACs and potential HDAC5 downstream targets. RESULTS We found that HDAC5 overexpression in dorsal striatum increased meth seeking on withdrawal day 30 but not day 2. In contrast, HDAC5 knockdown in the dorsal striatum decreased meth seeking on withdrawal day 30 but not on day 2; this manipulation also altered other HDACs (Hdac1 and Hdac4) and potential HDAC5 targets (Gnb4 and Suv39h1). CONCLUSIONS Results demonstrate a novel role of dorsal striatum HDAC5 in incubation of meth craving. These findings also set up future work to identify HDAC5 targets that mediate this incubation.
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Affiliation(s)
- Xuan Li
- Intramural Research Program, National Institute on Drug Abuse, National Institutes of Health, Department of Health and Human Services, Baltimore, Maryland.
| | - Maria B. Carreria
- Neuroscience Graduate Program, University of Texas Southwestern Medical Center, Dallas, TX
| | | | - Tamara Zeric
- Intramural Research Program, NIDA, NIH, DHHS, Baltimore, MD
| | | | | | - Jianjun Zhang
- CAS Key Laboratory of Mental Health, Institute of Psychology, Beijing, China
| | | | | | | | - Hyeon Son
- Department of Biochemistry and Molecular Biology, College of Medicine, Hanyang University, Korea
| | - Christopher W. Cowan
- Department of Neuroscience, Medical University of South Carolina, Charleston, MA
| | - Eric J. Nestler
- Fishberg Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, NY
| | - Yavin Shaham
- Intramural Research Program, NIDA, NIH, DHHS, Baltimore, MD
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Dogra S, Sona C, Kumar A, Yadav PN. Epigenetic regulation of G protein coupled receptor signaling and its implications in psychiatric disorders. Int J Biochem Cell Biol 2016; 77:226-39. [PMID: 27046448 DOI: 10.1016/j.biocel.2016.03.012] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2016] [Revised: 03/21/2016] [Accepted: 03/22/2016] [Indexed: 12/21/2022]
Abstract
G protein-coupled receptors (GPCRs) act as a relay center through which extracellular signals, in the form of neurotransmitters or therapeutics, are converted into an intracellular response, which ultimately shapes the overall response at the tissue and behavioral level. Remarkably in similar ways, epigenetic mechanisms also modulate the expression pattern of a large number of genes in response to the dynamic environment inside and outside of the body, and consequently overall response. Emerging evidences from the pharmacogenomics and preclinical studies clearly suggest that these two distinct mechanisms criss-cross each other in several neurological disorders. At one hand such cross-talks between two distinct mechanisms make disease etiology more challenging to understand, while on the other hand if dealt appropriately, such situations might provide an opportunity to find novel druggable target and strategy for the treatment of complex diseases. In this review article, we have summarized and highlighted the main findings that tie epigenetic mechanisms to GPCR mediated signaling in the pathophysiology of central nervous system (CNS) disorders, including depression, addiction and pain.
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Affiliation(s)
- Shalini Dogra
- Division of Pharmacology, CSIR-Central Drug Research Institute, Lucknow, UP 226031, India
| | - Chandan Sona
- Division of Pharmacology, CSIR-Central Drug Research Institute, Lucknow, UP 226031, India
| | - Ajeet Kumar
- Division of Pharmacology, CSIR-Central Drug Research Institute, Lucknow, UP 226031, India
| | - Prem N Yadav
- Division of Pharmacology, CSIR-Central Drug Research Institute, Lucknow, UP 226031, India.
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Wang X, Ning Y, Guo X. Integrative meta-analysis of differentially expressed genes in osteoarthritis using microarray technology. Mol Med Rep 2015; 12:3439-3445. [PMID: 25975828 PMCID: PMC4526045 DOI: 10.3892/mmr.2015.3790] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2014] [Accepted: 04/22/2015] [Indexed: 01/15/2023] Open
Abstract
The aim of the present study was to identify differentially expressed (DE) genes in patients with osteoarthritis (OA), and biological processes associated with changes in gene expression that occur in this disease. Using the INMEX (integrative meta-analysis of expression data) software tool, a meta-analysis of publicly available microarray Gene Expression Omnibus (GEO) datasets of OA was performed. Gene ontology (GO) enrichment analysis was performed in order to detect enriched functional attributes based on gene-associated GO terms. Three GEO datasets, containing 137 patients with OA and 52 healthy controls, were included in the meta-analysis. The analysis identified 85 genes that were consistently differentially expressed in OA (30 genes were upregulated and 55 genes were downregulated). The upregulated gene with the lowest P-value (P=5.36E-07) was S-phase kinase-associated protein 2, E3 ubiquitin protein ligase (SKP2). The downregulated gene with the lowest P-value (P=4.42E-09) was Proline rich 5 like (PRR5L). Among the 210 GO terms that were associated with the set of DE genes, the most significant two enrichments were observed in the GO categories of 'Immune response', with a P-value of 0.000129438, and 'Immune effectors process', with a P-value of 0.000288619. The current meta-analysis identified genes that were consistently DE in OA, in addition to biological pathways associated with changes in gene expression that occur during OA, which may provide insight into the molecular mechanisms underlying the pathogenesis of this disease.
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Affiliation(s)
- Xi Wang
- School of Public Health, Xi'an Jiaotong University Health Science Center, Key Laboratory of Trace Elements and Endemic Diseases, National Health and Family Planning Commission, Xi'an, Shaanxi 710061, P.R. China
| | - Yujie Ning
- School of Public Health, Xi'an Jiaotong University Health Science Center, Key Laboratory of Trace Elements and Endemic Diseases, National Health and Family Planning Commission, Xi'an, Shaanxi 710061, P.R. China
| | - Xiong Guo
- School of Public Health, Xi'an Jiaotong University Health Science Center, Key Laboratory of Trace Elements and Endemic Diseases, National Health and Family Planning Commission, Xi'an, Shaanxi 710061, P.R. China
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8
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White SM, North LM, Haines E, Goldberg M, Sullivan LM, Pressly JD, Weber DS, Park F, Regner KR. G-protein βγ subunit dimers modulate kidney repair after ischemia-reperfusion injury in rats. Mol Pharmacol 2014; 86:369-77. [PMID: 25028481 DOI: 10.1124/mol.114.092346] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Heterotrimeric G-proteins play a crucial role in the control of renal epithelial cell function during homeostasis and in response to injury. In this report, G-protein βγ subunit (Gβγ) dimer activity was evaluated during the process of tubular repair after renal ischemia-reperfusion injury (IRI) in male Sprague Dawley rats. Rats were treated with a small molecule inhibitor of Gβγ activity, gallein (30 or 100 mg/kg), 1 hour after reperfusion and every 24 hours for 3 additional days. After IRI, renal dysfunction was prolonged after the high-dose gallein treatment in comparison with vehicle treatment during the 7-day recovery period. Renal tubular repair in the outer medulla 7 days after IRI was significantly (P < 0.001) attenuated after treatment with high-dose gallein (100 mg/kg) in comparison with low-dose gallein (30 mg/kg), or the vehicle and fluorescein control groups. Gallein treatment significantly reduced (P < 0.05) the number of proliferating cell nuclear antigen-positive tubular epithelial cells at 24 hours after the ischemia-reperfusion phase in vivo. In vitro application of gallein on normal rat kidney (NRK-52E) proximal tubule cells significantly reduced (P < 0.05) S-phase cell cycle entry compared with vehicle-treated cells as determined by 5'-bromo-2'-deoxyuridine incorporation. Taken together, these data suggest that Gβγ signaling contributes to the maintenance and repair of renal tubular epithelium and may be a novel therapeutic target for the development of drugs to treat acute kidney injury.
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Affiliation(s)
- Sarah M White
- Department of Medicine, Division of Nephrology (S.M.W., L.M.N., E.H., M.G., K.R.R.), Cardiovascular Research Center (K.R.R.), Medical College of Wisconsin, Milwaukee, Wisconsin; Department of Pharmaceutical Sciences, University of Tennessee Health Sciences Center, Memphis, Tennessee (J.D.P., F.P.); and Department of Physiology, University of South Alabama, Mobile, Alabama (L.M.S., D.S.W.)
| | - Lauren M North
- Department of Medicine, Division of Nephrology (S.M.W., L.M.N., E.H., M.G., K.R.R.), Cardiovascular Research Center (K.R.R.), Medical College of Wisconsin, Milwaukee, Wisconsin; Department of Pharmaceutical Sciences, University of Tennessee Health Sciences Center, Memphis, Tennessee (J.D.P., F.P.); and Department of Physiology, University of South Alabama, Mobile, Alabama (L.M.S., D.S.W.)
| | - Emily Haines
- Department of Medicine, Division of Nephrology (S.M.W., L.M.N., E.H., M.G., K.R.R.), Cardiovascular Research Center (K.R.R.), Medical College of Wisconsin, Milwaukee, Wisconsin; Department of Pharmaceutical Sciences, University of Tennessee Health Sciences Center, Memphis, Tennessee (J.D.P., F.P.); and Department of Physiology, University of South Alabama, Mobile, Alabama (L.M.S., D.S.W.)
| | - Megan Goldberg
- Department of Medicine, Division of Nephrology (S.M.W., L.M.N., E.H., M.G., K.R.R.), Cardiovascular Research Center (K.R.R.), Medical College of Wisconsin, Milwaukee, Wisconsin; Department of Pharmaceutical Sciences, University of Tennessee Health Sciences Center, Memphis, Tennessee (J.D.P., F.P.); and Department of Physiology, University of South Alabama, Mobile, Alabama (L.M.S., D.S.W.)
| | - Lydia M Sullivan
- Department of Medicine, Division of Nephrology (S.M.W., L.M.N., E.H., M.G., K.R.R.), Cardiovascular Research Center (K.R.R.), Medical College of Wisconsin, Milwaukee, Wisconsin; Department of Pharmaceutical Sciences, University of Tennessee Health Sciences Center, Memphis, Tennessee (J.D.P., F.P.); and Department of Physiology, University of South Alabama, Mobile, Alabama (L.M.S., D.S.W.)
| | - Jeffrey D Pressly
- Department of Medicine, Division of Nephrology (S.M.W., L.M.N., E.H., M.G., K.R.R.), Cardiovascular Research Center (K.R.R.), Medical College of Wisconsin, Milwaukee, Wisconsin; Department of Pharmaceutical Sciences, University of Tennessee Health Sciences Center, Memphis, Tennessee (J.D.P., F.P.); and Department of Physiology, University of South Alabama, Mobile, Alabama (L.M.S., D.S.W.)
| | - David S Weber
- Department of Medicine, Division of Nephrology (S.M.W., L.M.N., E.H., M.G., K.R.R.), Cardiovascular Research Center (K.R.R.), Medical College of Wisconsin, Milwaukee, Wisconsin; Department of Pharmaceutical Sciences, University of Tennessee Health Sciences Center, Memphis, Tennessee (J.D.P., F.P.); and Department of Physiology, University of South Alabama, Mobile, Alabama (L.M.S., D.S.W.)
| | - Frank Park
- Department of Medicine, Division of Nephrology (S.M.W., L.M.N., E.H., M.G., K.R.R.), Cardiovascular Research Center (K.R.R.), Medical College of Wisconsin, Milwaukee, Wisconsin; Department of Pharmaceutical Sciences, University of Tennessee Health Sciences Center, Memphis, Tennessee (J.D.P., F.P.); and Department of Physiology, University of South Alabama, Mobile, Alabama (L.M.S., D.S.W.)
| | - Kevin R Regner
- Department of Medicine, Division of Nephrology (S.M.W., L.M.N., E.H., M.G., K.R.R.), Cardiovascular Research Center (K.R.R.), Medical College of Wisconsin, Milwaukee, Wisconsin; Department of Pharmaceutical Sciences, University of Tennessee Health Sciences Center, Memphis, Tennessee (J.D.P., F.P.); and Department of Physiology, University of South Alabama, Mobile, Alabama (L.M.S., D.S.W.)
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Sathyanesan A, Feijoo AA, Mehta ST, Nimarko AF, Lin W. Expression profile of G-protein βγ subunit gene transcripts in the mouse olfactory sensory epithelia. Front Cell Neurosci 2013; 7:84. [PMID: 23759900 PMCID: PMC3671183 DOI: 10.3389/fncel.2013.00084] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2013] [Accepted: 05/16/2013] [Indexed: 11/24/2022] Open
Abstract
Heterotrimeric G-proteins mediate a variety of cellular functions, including signal transduction in sensory neurons of the olfactory system. Whereas the Gα subunits in these neurons are well characterized, the gene transcript expression profile of Gβγ subunits is largely missing. Here we report our comprehensive expression analysis to identify Gβ and Gγ subunit gene transcripts in the mouse main olfactory epithelium (MOE) and the vomeronasal organ (VNO). Our reverse transcriptase PCR (RT-PCR) and realtime qPCR analyses of all known Gβ (β1,2,3,4,5) and Gγ (γ1,2,2t,3,4,5,7,8,10,11,12,13) subunits indicate presence of multiple Gβ and Gγ subunit gene transcripts in the MOE and the VNO at various expression levels. These results are supported by our RNA in situ hybridization (RISH) experiments, which reveal the expression patterns of two Gβ subunits and four Gγ subunits in the MOE as well as one Gβ and four Gγ subunits in the VNO. Using double-probe fluorescence RISH and line intensity scan analysis of the RISH signals of two dominant Gβγ subunits, we show that Gγ13 is expressed in mature olfactory sensory neurons (OSNs), while Gβ1 is present in both mature and immature OSNs. Interestingly, we also found Gβ1 to be the dominant Gβ subunit in the VNO and present throughout the sensory epithelium. In contrast, we found diverse expression of Gγ subunit gene transcripts with Gγ2, Gγ3, and Gγ13 in the Gαi2-expressing neuronal population, while Gγ8 is expressed in both layers. Further, we determined the expression of these Gβγ gene transcripts in three post-natal developmental stages (p0, 7, and 14) and found their cell-type specific expression remains largely unchanged, except the transient expression of Gγ2 in a single basal layer of cells in the MOE during P7 and P14. Taken together, our comprehensive expression analyses reveal cell-type specific gene expression of multiple Gβ and Gγ in sensory neurons of the olfactory system.
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Affiliation(s)
- Aaron Sathyanesan
- Department of Biological Sciences, University of Maryland Baltimore County, Baltimore MD, USA
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10
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Soong BW, Huang YH, Tsai PC, Huang CC, Pan HC, Lu YC, Chien HJ, Liu TT, Chang MH, Lin KP, Tu PH, Kao LS, Lee YC. Exome sequencing identifies GNB4 mutations as a cause of dominant intermediate Charcot-Marie-Tooth disease. Am J Hum Genet 2013; 92:422-30. [PMID: 23434117 DOI: 10.1016/j.ajhg.2013.01.014] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2012] [Revised: 11/26/2012] [Accepted: 01/19/2013] [Indexed: 01/30/2023] Open
Abstract
Charcot-Marie-Tooth disease (CMT) is a heterogeneous group of inherited neuropathies. Mutations in approximately 45 genes have been identified as being associated with CMT. Nevertheless, the genetic etiologies of at least 30% of CMTs have yet to be elucidated. Using a genome-wide linkage study, we previously mapped a dominant intermediate CMT to chromosomal region 3q28-q29. Subsequent exome sequencing of two affected first cousins revealed heterozygous mutation c.158G>A (p.Gly53Asp) in GNB4, encoding guanine-nucleotide-binding protein subunit beta-4 (Gβ4), to cosegregate with the CMT phenotype in the family. Further analysis of GNB4 in an additional 88 unrelated CMT individuals uncovered another de novo mutation, c.265A>G (p.Lys89Glu), in this gene in one individual. Immunohistochemistry studies revealed that Gβ4 was abundant in the axons and Schwann cells of peripheral nerves and that expression of Gβ4 was significantly reduced in the sural nerve of the two individuals carrying the c.158G>A (p.Gly53Asp) mutation. In vitro studies demonstrated that both the p.Gly53Asp and p.Lys89Glu altered proteins impaired bradykinin-induced G-protein-coupled-receptor (GPCR) signaling, which was facilitated by the wild-type Gβ4. This study identifies GNB4 mutations as a cause of CMT and highlights the importance of Gβ4-related GPCR signaling in peripheral-nerve function in humans.
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11
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Eijgelsheim M, Newton-Cheh C, Sotoodehnia N, de Bakker PIW, Müller M, Morrison AC, Smith AV, Isaacs A, Sanna S, Dörr M, Navarro P, Fuchsberger C, Nolte IM, de Geus EJC, Estrada K, Hwang SJ, Bis JC, Rückert IM, Alonso A, Launer LJ, Hottenga JJ, Rivadeneira F, Noseworthy PA, Rice KM, Perz S, Arking DE, Spector TD, Kors JA, Aulchenko YS, Tarasov KV, Homuth G, Wild SH, Marroni F, Gieger C, Licht CM, Prineas RJ, Hofman A, Rotter JI, Hicks AA, Ernst F, Najjar SS, Wright AF, Peters A, Fox ER, Oostra BA, Kroemer HK, Couper D, Völzke H, Campbell H, Meitinger T, Uda M, Witteman JCM, Psaty BM, Wichmann HE, Harris TB, Kääb S, Siscovick DS, Jamshidi Y, Uitterlinden AG, Folsom AR, Larson MG, Wilson JF, Penninx BW, Snieder H, Pramstaller PP, van Duijn CM, Lakatta EG, Felix SB, Gudnason V, Pfeufer A, Heckbert SR, Stricker BHC, Boerwinkle E, O'Donnell CJ. Genome-wide association analysis identifies multiple loci related to resting heart rate. Hum Mol Genet 2010; 19:3885-94. [PMID: 20639392 DOI: 10.1093/hmg/ddq303] [Citation(s) in RCA: 104] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
Higher resting heart rate is associated with increased cardiovascular disease and mortality risk. Though heritable factors play a substantial role in population variation, little is known about specific genetic determinants. This knowledge can impact clinical care by identifying novel factors that influence pathologic heart rate states, modulate heart rate through cardiac structure and function or by improving our understanding of the physiology of heart rate regulation. To identify common genetic variants associated with heart rate, we performed a meta-analysis of 15 genome-wide association studies (GWAS), including 38,991 subjects of European ancestry, estimating the association between age-, sex- and body mass-adjusted RR interval (inverse heart rate) and approximately 2.5 million markers. Results with P < 5 × 10(-8) were considered genome-wide significant. We constructed regression models with multiple markers to assess whether results at less stringent thresholds were likely to be truly associated with RR interval. We identified six novel associations with resting heart rate at six loci: 6q22 near GJA1; 14q12 near MYH7; 12p12 near SOX5, c12orf67, BCAT1, LRMP and CASC1; 6q22 near SLC35F1, PLN and c6orf204; 7q22 near SLC12A9 and UfSp1; and 11q12 near FADS1. Associations at 6q22 400 kb away from GJA1, at 14q12 MYH6 and at 1q32 near CD34 identified in previously published GWAS were confirmed. In aggregate, these variants explain approximately 0.7% of RR interval variance. A multivariant regression model including 20 variants with P < 10(-5) increased the explained variance to 1.6%, suggesting that some loci falling short of genome-wide significance are likely truly associated. Future research is warranted to elucidate underlying mechanisms that may impact clinical care.
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Affiliation(s)
- Mark Eijgelsheim
- Department of Epidemiology, Erasmus Medical Center, Rotterdam, The Netherlands
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12
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McIntire WE. Structural determinants involved in the formation and activation of G protein betagamma dimers. Neurosignals 2009; 17:82-99. [PMID: 19212142 DOI: 10.1159/000186692] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2008] [Accepted: 05/13/2008] [Indexed: 01/08/2023] Open
Abstract
Heterotrimeric G proteins, composed of an alpha, beta and gamma subunit, represent one of the most important and dynamic families of signaling proteins. As a testament to the significance of G protein signaling, the hundreds of seven-transmembrane-spanning receptors that interact with G proteins are estimated to occupy 1-2% of the human genome. This broad diversity of receptors is echoed in the number of potential heterotrimer combinations that can arise from the 23 alpha subunit, 7 beta subunit and 12 gamma subunit isoforms that have been identified. The potential for such vast complexity implies that the receptor G protein interface is the site of much regulation. The historical model for the activation of a G protein holds that activated receptor catalyzes the exchange of GDP for GTP on the alpha subunit, inducing a conformational change that substantially lowers the affinity of alpha for betagamma. This decreased affinity enables dissociation of betagamma from alpha and receptor. The free form of betagamma is thought to activate effectors, until the hydrolysis of GTP by G alpha (aided by RGS proteins) allows the subunits to re-associate, effectively deactivating the G protein until another interaction with activated receptor.
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Affiliation(s)
- William E McIntire
- Department of Pharmacology, University of Virginia Health System, Charlottesville, VA 22908, USA.
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13
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Renthal W, Maze I, Krishnan V, Covington HE, Xiao G, Kumar A, Russo SJ, Graham A, Tsankova N, Kippin TE, Kerstetter KA, Neve RL, Haggarty SJ, McKinsey TA, Bassel-Duby R, Olson EN, Nestler EJ. Histone Deacetylase 5 Epigenetically Controls Behavioral Adaptations to Chronic Emotional Stimuli. Neuron 2007; 56:517-29. [DOI: 10.1016/j.neuron.2007.09.032] [Citation(s) in RCA: 484] [Impact Index Per Article: 28.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2007] [Revised: 08/23/2007] [Accepted: 09/26/2007] [Indexed: 11/28/2022]
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McIntire WE, MacCleery G, Murphree LJ, Kerchner KR, Linden J, Garrison JC. Influence of differential stability of G protein βγ dimers containing the γ11 subunit on functional activity at the M1 muscarinic receptor, A1 adenosine receptor, and phospholipase C-β. Biochemistry 2006; 45:11616-31. [PMID: 16981721 DOI: 10.1021/bi0604882] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Ggamma11 is an unusual guanine nucleotide-binding regulatory protein (G protein) subunit. To study the effect of different Gbeta-binding partners on gamma11 function, four recombinant betagamma dimers, beta1gamma2, beta4gamma2, beta1gamma11, and beta4gamma11, were characterized in a receptor reconstitution assay with the G(q)-linked M1 muscarinic and the G(i1)-linked A1 adenosine receptors. The beta4gamma11 dimer was up to 30-fold less efficient than beta4gamma2 at promoting agonist-dependent binding of [35S]GTPgammaS to either alpha(q) or alpha(i1). Using a competition assay to measure relative affinities of purified betagamma dimers for alpha, the beta4gamma11 dimer had a 15-fold lower affinity for G(i1) alpha than beta4gamma2. Chromatographic characterization of the beta4gamma11 dimer revealed that the betagamma is stable in a heterotrimeric complex with G(i1) alpha; however, upon activation of alpha with MgCl2 and GTPgammaS under nondenaturing conditions, the beta4 and gamma11 subunits dissociate. Activation of purified G(i1) alpha:beta4gamma11 with Mg+2/GTPgammaS following reconstitution into lipid vesicles and incubation with phospholipase C (PLC)-beta resulted in stimulation of PLC-beta activity; however, when this activation preceded reconstitution into vesicles, PLC-beta activity was markedly diminished. In a membrane coupling assay designed to measure the ability of G protein to promote a high-affinity agonist-binding conformation of the A1 adenosine receptor, beta4gamma11 was as effective as beta4gamma2 when coexpressed with G(i1) alpha and receptor. However, G(i1) alpha:beta4gamma11-induced high-affinity binding was up to 20-fold more sensitive to GTPgammaS than G(i1) alpha:beta4gamma2-induced high-affinity binding. These results suggest that the stability of the beta4gamma11 dimer can modulate G protein activity at the receptor and effector.
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Affiliation(s)
- William E McIntire
- Department of Pharmacology, University of Virginia Health System, Post Office Box 800735, 1300 Jefferson Park Avenue, Charlottesville, Virginia 22908, USA.
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15
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Khan KM, Sarfaraz N, Siddiqui S, Nawaz H. Immunohistochemical localization of G protein betagamma subunits in the lateral wall of the rat cochlea. J Anat 2006; 208:205-18. [PMID: 16441565 PMCID: PMC2100195 DOI: 10.1111/j.1469-7580.2006.00526.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022] Open
Abstract
The role of G protein-mediated signal transduction in the production of endolymph, an extracellular fluid of unusual ionic composition, is beginning to be understood. The identity of Galpha subunits in the stria vascularis and the spiral ligament of the lateral wall of the cochlear duct is well established. However, little is known about the presence of betagamma subunits. This study used immunohistochemistry to investigate the distribution of G protein betagamma subunits in the lateral wall of the cochlea. Temporal bones of 6- to 8-week-old rats were fixed in 4% paraformaldehyde and 0.1% glutaraldehyde and processed for embedding in paraffin wax. The dewaxed, midmodiolar sections of the cochlea were incubated with subunit-specific polyclonal antibodies. The results show that the pattern of immunoreactivity varies for the G protein beta1-4 and gamma1-3, 5 and 7 subunits in the stria vascularis and spiral ligament. In the stria vascularis, immunoreactivity was detected for beta2, beta3, beta4, gamma1, gamma2 and gamma7 subunits. All five types of fibrocytes in the spiral ligament exhibited positive staining for gamma2 and gamma7. However, immunoreactivity for beta1-4 subunits was variable. Immunoreactivity for gamma3 and gamma5 subunits was not detected in the lateral cochlear wall. The expression pattern of G protein betagamma subunits in lateral wall provides a basis for interpreting the functions of G protein-coupled receptors in cochlear fluid homeostasis.
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Affiliation(s)
- Khalid M Khan
- Department of Biological & Biomedical Sciences, Faculty of Health Sciences, The Aga Khan University, Karachi, Pakistan.
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Krumins AM, Gilman AG. Targeted knockdown of G protein subunits selectively prevents receptor-mediated modulation of effectors and reveals complex changes in non-targeted signaling proteins. J Biol Chem 2006; 281:10250-62. [PMID: 16446365 DOI: 10.1074/jbc.m511551200] [Citation(s) in RCA: 92] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Heterotrimeric G protein signaling specificity has been attributed to select combinations of Galpha, beta, and gamma subunits, their interactions with other signaling proteins, and their localization in the cell. With few exceptions, the G protein subunit combinations that exist in vivo and the significance of these specific combinations are largely unknown. We have begun to approach these problems in HeLa cells by: 1) determining the concentrations of Galpha and Gbeta subunits; 2) examining receptor-dependent activities of two effector systems (adenylyl cyclase and phospholipase Cbeta); and 3) systematically silencing each of the Galpha and Gbeta subunits by using small interfering RNA while quantifying resultant changes in effector function and the concentrations of other relevant proteins in the network. HeLa cells express equimolar amounts of total Galpha and Gbeta subunits. The most prevalent Galpha proteins were one member of each Galpha subfamily (Galpha(s), Galpha(i3), Galpha(11), and Galpha(13)). We substantially abrogated expression of most of the Galpha and Gbeta proteins expressed in these cells, singly and some in combinations. As expected, agonist-dependent activation of adenylyl cyclase or phospholipase Cbeta was specifically eliminated following the silencing of Galpha(s) or Galpha(q/11), respectively. We also confirmed that Gbeta subunits are necessary for stable accumulation of Galpha proteins in vivo. Gbeta subunits demonstrated little isoform specificity for receptor-dependent modulation of effector activity. We observed compensatory changes in G protein accumulation following silencing of individual genes, as well as an apparent reciprocal relationship between the expression of certain Galpha(q) and Galpha(i) subfamily members. These findings provide a foundation for understanding the mechanisms that regulate the adaptability and remarkable resilience of G protein signaling networks.
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Affiliation(s)
- Andrejs M Krumins
- Department of Pharmacology, The University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
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Rosskopf D, Nikula C, Manthey I, Joisten M, Frey U, Kohnen S, Siffert W. The human G protein beta4 subunit: gene structure, expression, Ggamma and effector interaction. FEBS Lett 2003; 544:27-32. [PMID: 12782285 DOI: 10.1016/s0014-5793(03)00441-1] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
The aim of this study was the characterization of the human Gbeta4 subunit of heterotrimeric G proteins. Human Gbeta4 is widely expressed. Its gene is located on chromosome 3 with a genomic structure indistinguishable from that of the genes of Gbeta1 to Gbeta3, but entirely different from Gbeta5. In vitro translation co-precipitation analyses revealed that Gbeta4 can form stable dimers with Ggamma1, Ggamma2, Ggamma3, Ggamma4, Ggamma5, Ggamma7, Ggamma10, Ggamma11, Ggamma12, and Ggamma13, dimers which were also able to stimulate phospholipase beta2.
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Affiliation(s)
- Dieter Rosskopf
- Institut für Pharmakologie, Universitätsklinikum Essen, Hufelandstr. 55, Germany.
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Ruiz-Velasco V, Ikeda SR. A splice variant of the G protein beta 3-subunit implicated in disease states does not modulate ion channels. Physiol Genomics 2003; 13:85-95. [PMID: 12595577 DOI: 10.1152/physiolgenomics.00057.2002] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
A single-nucleotide polymorphism (C825T) in the GNB3 gene produces an alternative splice variant of the heterotrimeric G protein beta3 subunit (Gbeta3). Translation of the alternatively spliced mRNA results in a protein product, Gbeta3-s, in which 41 amino acids are deleted from Gbeta3. Interestingly, previous studies indicate that the C825T allele occurs with a high frequency in patients with certain vascular disorders. However, little information is available regarding the functional role Gbeta3-s might play in ion channel modulation. To examine this aspect, Gbeta3 or Gbeta3-s, along with either Ggamma2 or Ggamma5, were expressed in rat sympathetic neurons by nuclear microinjection of vector encoding the desired protein. In contrast to Gbeta3, expression of Gbeta3-s did not modulate N-type Ca(2+) or G protein-gated inwardly rectifying K(+) channels. In addition, Gbeta3-s did not appear to complex with a pertussis toxin-insensitive mutant of Galpha(i2) or couple to natively expressed alpha(2)-adrenergic receptors. Finally, fluorescence resonance energy transfer (FRET) measurements indicated that enhanced yellow fluorescent protein (EYFP)-labeled Gbeta3-s does not form a Gbetagamma heterodimer when coexpressed with enhanced cyan fluorescent protein (ECFP)-labeled Ggamma2. Therefore, when expressed in sympathetic neurons, Gbeta3-s appears to lack biological activity--hence pathological conditions in patients carrying the homozygous C825T allele may result from a functional knockout of Gbeta3.
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Affiliation(s)
- Victor Ruiz-Velasco
- Laboratory of Molecular Physiology, Guthrie Research Institute, Sayre, Pennsylvania 18840, USA.
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