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Spicer MM, Weber MA, Luo Z, Yang J, Narayanan NS, Fisher RA. Regulator of G protein signaling 6 (RGS6) in dopamine neurons promotes EtOH seeking, behavioral reward, and susceptibility to relapse. Psychopharmacology (Berl) 2024:10.1007/s00213-024-06631-8. [PMID: 38856764 DOI: 10.1007/s00213-024-06631-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/14/2023] [Accepted: 05/31/2024] [Indexed: 06/11/2024]
Abstract
Mesolimbic dopamine (DA) transmission is believed to play a critical role in mediating reward responses to drugs of abuse, including alcohol (EtOH). The neurobiological mechanisms underlying EtOH-seeking behavior and dependence are not fully understood, and abstinence remains the only effective way to prevent alcohol use disorders (AUDs). Here, we developed novel RGS6fl/fl; DAT-iCreER mice to determine the role of RGS6 in DA neurons on EtOH consumption, reward, and relapse behaviors. We found that RGS6 is expressed in DA neurons in both human and mouse ventral tegmental area (VTA), and that RGS6 loss in mice upregulates DA transporter (DAT) expression in VTA DA neuron synaptic terminals. Remarkably, loss of RGS6 in DA neurons significantly reduced EtOH consumption, preference, and reward in a manner indistinguishable from that seen in RGS6-/- mice. Strikingly, RGS6 loss from DA neurons before or after EtOH behavioral reward is established significantly reduced (~ 50%) re-instatement of reward following extinguishment, demonstrating distinct roles of RGS6 in promoting reward and relapse susceptibility to EtOH. These studies identify DA neurons as the locus of RGS6 action in promoting EtOH consumption, preference, reward, and relapse. RGS6 is unique among R7 RGS proteins in promoting rather than suppressing behavioral responses to drugs of abuse and to modulate EtOH behavioral reward. This is a result of RGS6's pre-synaptic actions that we hypothesize promote VTA DA transmission by suppressing GPCR-Gαi/o-DAT signaling in VTA DA neurons. These studies identify RGS6 as a potential therapeutic target for behavioral reward and relapse to EtOH.
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Affiliation(s)
- Mackenzie M Spicer
- Department of Neuroscience and Pharmacology, University of Iowa Carver College of Medicine, 51 Newton Rd. BSB 2-512, Iowa City, IA, 52242, USA
- Iowa Neuroscience Institute, University of Iowa Carver College of Medicine, 169 Newton Rd., Iowa City, IA, 52242, USA
- Department of Neurology, University of Iowa Carver College of Medicine, 200 Hawkins Dr., Iowa City, IA, 52242, USA
| | - Matthew A Weber
- Iowa Neuroscience Institute, University of Iowa Carver College of Medicine, 169 Newton Rd., Iowa City, IA, 52242, USA
- Department of Neurology, University of Iowa Carver College of Medicine, 200 Hawkins Dr., Iowa City, IA, 52242, USA
| | - Zili Luo
- Department of Pediatrics, University of Iowa Carver College of Medicine, 200 Hawkins Dr., Iowa City, IA, 52242, USA
| | - Jianqi Yang
- Department of Neuroscience and Pharmacology, University of Iowa Carver College of Medicine, 51 Newton Rd. BSB 2-512, Iowa City, IA, 52242, USA
- Iowa Neuroscience Institute, University of Iowa Carver College of Medicine, 169 Newton Rd., Iowa City, IA, 52242, USA
| | - Nandakumar S Narayanan
- Iowa Neuroscience Institute, University of Iowa Carver College of Medicine, 169 Newton Rd., Iowa City, IA, 52242, USA
- Department of Neurology, University of Iowa Carver College of Medicine, 200 Hawkins Dr., Iowa City, IA, 52242, USA
| | - Rory A Fisher
- Department of Neuroscience and Pharmacology, University of Iowa Carver College of Medicine, 51 Newton Rd. BSB 2-512, Iowa City, IA, 52242, USA.
- Iowa Neuroscience Institute, University of Iowa Carver College of Medicine, 169 Newton Rd., Iowa City, IA, 52242, USA.
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Chung YK, Chan HY, Lee TY, Wong YH. Inhibition of adenylyl cyclase by GTPase-deficient Gα i is mechanistically different from that mediated by receptor-activated Gα i. Cell Commun Signal 2024; 22:218. [PMID: 38581012 PMCID: PMC10996109 DOI: 10.1186/s12964-024-01572-3] [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: 01/20/2024] [Accepted: 03/16/2024] [Indexed: 04/07/2024] Open
Abstract
Signal transduction through G protein-coupled receptors (GPCRs) has been a major focus in cell biology for decades. Numerous disorders are associated with GPCRs that utilize Gi proteins to inhibit adenylyl cyclase (AC) as well as regulate other effectors. Several early studies have successfully defined the AC-interacting domains of several members of Gαi by measuring the loss of activity upon homologous replacements of putative regions of constitutive active Gαi mutants. However, whether such findings can indeed be translated into the context of a receptor-activated Gαi have not been rigorously verified. To address this issue, an array of known and new chimeric mutations was introduced into GTPase-deficient Q204L (QL) and R178C (RC) mutants of Gαi1, followed by examinations on their ability to inhibit AC. Surprisingly, most chimeras failed to abolish the constitutive activity brought on by the QL mutation, while some were able to eliminate the inhibitory activity of RC mutants. Receptor-mediated inhibition of AC was similarly observed in the same chimeric constructs harbouring the pertussis toxin (PTX)-resistant C351I mutation. Moreover, RC-bearing loss-of-function chimeras appeared to be hyper-deactivated by endogenous RGS protein. Molecular docking revealed a potential interaction between AC and the α3/β5 loop of Gαi1. Subsequent cAMP assays support a cooperative action of the α3/β5 loop, the α4 helix, and the α4/β6 loop in mediating AC inhibition by Gαi1-i3. Our results unveiled a notable functional divergence between constitutively active mutants and receptor-activated Gαi1 to inhibit AC, and identified a previously unknown AC-interacting domain of Gαi subunits. These results collectively provide valuable insights on the mechanism of AC inhibition in the cellular environment.
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Affiliation(s)
- Yin Kwan Chung
- Division of Life Science and Biotechnology Research Institute, Hong Kong University of Science and Technology, Hong Kong, China
- Rudolf Schönheimer Institute of Biochemistry, Division of General Biochemistry, Medical Faculty, Leipzig University, Johannisallee 30, 04103, Leipzig, Germany
| | - Ho Yung Chan
- Division of Life Science and Biotechnology Research Institute, Hong Kong University of Science and Technology, Hong Kong, China
| | - Tung Yeung Lee
- Division of Life Science and Biotechnology Research Institute, Hong Kong University of Science and Technology, Hong Kong, China
| | - Yung Hou Wong
- Division of Life Science and Biotechnology Research Institute, Hong Kong University of Science and Technology, Hong Kong, China.
- State Key Laboratory of Molecular Neuroscience, and the Molecular Neuroscience Center, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China.
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Garcia-Marcos M. Heterotrimeric G protein signaling without GPCRs: The Gα-binding-and-activating (GBA) motif. J Biol Chem 2024; 300:105756. [PMID: 38364891 PMCID: PMC10943482 DOI: 10.1016/j.jbc.2024.105756] [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: 10/28/2023] [Revised: 01/30/2024] [Accepted: 02/02/2024] [Indexed: 02/18/2024] Open
Abstract
Heterotrimeric G proteins (Gαβγ) are molecular switches that relay signals from 7-transmembrane receptors located at the cell surface to the cytoplasm. The function of these receptors is so intimately linked to heterotrimeric G proteins that they are named G protein-coupled receptors (GPCRs), showcasing the interdependent nature of this archetypical receptor-transducer axis of transmembrane signaling in eukaryotes. It is generally assumed that activation of heterotrimeric G protein signaling occurs exclusively by the action of GPCRs, but this idea has been challenged by the discovery of alternative mechanisms by which G proteins can propagate signals in the cell. This review will focus on a general principle of G protein signaling that operates without the direct involvement of GPCRs. The mechanism of G protein signaling reviewed here is mediated by a class of G protein regulators defined by containing an evolutionarily conserved sequence named the Gα-binding-and-activating (GBA) motif. Using the best characterized proteins with a GBA motif as examples, Gα-interacting vesicle-associated protein (GIV)/Girdin and dishevelled-associating protein with a high frequency of leucine residues (DAPLE), this review will cover (i) the mechanisms by which extracellular cues not relayed by GPCRs promote the coupling of GBA motif-containing regulators with G proteins, (ii) the structural and molecular basis for how GBA motifs interact with Gα subunits to facilitate signaling, (iii) the relevance of this mechanism in different cellular and pathological processes, including cancer and birth defects, and (iv) strategies to manipulate GBA-G protein coupling for experimental therapeutics purposes, including the development of rationally engineered proteins and chemical probes.
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Affiliation(s)
- Mikel Garcia-Marcos
- Department of Biochemistry & Cell Biology, Chobanian & Avedisian School of Medicine, Boston University, Boston, Massachusetts, USA; Department of Biology, College of Arts & Sciences, Boston University, Boston, Massachusetts, USA.
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Spicer MM, Weber MA, Luo Z, Yang J, Narayanan NS, Fisher RA. Regulator of G protein signaling 6 (RGS6) in ventral tegmental area (VTA) dopamine neurons promotes EtOH seeking, behavioral reward and susceptibility to relapse. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.10.24.563844. [PMID: 37961154 PMCID: PMC10634791 DOI: 10.1101/2023.10.24.563844] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2023]
Abstract
Mesolimbic dopamine (DA) transmission is believed to play a critical role in mediating reward responses to drugs of abuse, including alcohol (EtOH). EtOH is the most abused substance worldwide with chronic consumption often leading to the development of dependence and abuse. Unfortunately, the neurobiological mechanisms underlying EtOH-seeking behavior and dependence are not fully understood, and abstinence remains the only effective way to prevent alcohol use disorders (AUDs). Here, we developed novel RGS6 fl/fl ; DAT-iCreER mice to determine the role of RGS6 in VTA DA neurons on EtOH consumption and reward behaviors. We found that RGS6 is expressed in DA neurons in both human and mouse VTA, and that RGS6 loss in mice upregulates DA transporter (DAT) expression in VTA DA neuron synaptic terminals. Remarkably, loss of RGS6 in VTA DA neurons significantly reduced EtOH consumption, preference, and reward in a manner indistinguishable from that seen in RGS6 -/- mice. Strikingly, RGS6 loss from VTA DA neurons before or after EtOH behavioral reward is established significantly reduced (∼50%) re-instatement of reward following extinguishment, demonstrating distinct roles of RGS6 in promoting reward and relapse susceptibility to EtOH. These studies illuminate a critical role of RGS6 in the mesolimbic circuit in promoting EtOH seeking, reward, and reinstatement. We propose that RGS6 functions to promote DA transmission through its function as a negative modulator of GPCR-Gα i/o -DAT signaling in VTA DA neurons. These studies identify RGS6 as a potential therapeutic target for behavioral reward and relapse to EtOH.
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Montañez-Miranda C, Perszyk RE, Harbin NH, Okalova J, Ramineni S, Traynelis SF, Hepler JR. Functional Assessment of Cancer-Linked Mutations in Sensitive Regions of Regulators of G Protein Signaling Predicted by Three-Dimensional Missense Tolerance Ratio Analysis. Mol Pharmacol 2023; 103:21-37. [PMID: 36384958 PMCID: PMC10955721 DOI: 10.1124/molpharm.122.000614] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2022] [Revised: 10/04/2022] [Accepted: 10/18/2022] [Indexed: 11/18/2022] Open
Abstract
Regulators of G protein signaling (RGS) proteins modulate G protein-coupled receptor (GPCR) signaling by acting as negative regulators of G proteins. Genetic variants in RGS proteins are associated with many diseases, including cancers, although the impact of these mutations on protein function is uncertain. Here we analyze the RGS domains of 15 RGS protein family members using a novel bioinformatic tool that measures the missense tolerance ratio (MTR) using a three-dimensional (3D) structure (3DMTR). Subsequent permutation analysis can define the protein regions that are most significantly intolerant (P < 0.05) in each dataset. We further focused on RGS14, RGS10, and RGS4. RGS14 exhibited seven significantly tolerant and seven significantly intolerant residues, RGS10 had six intolerant residues, and RGS4 had eight tolerant and six intolerant residues. Intolerant and tolerant-control residues that overlap with pathogenic cancer mutations reported in the COSMIC cancer database were selected to define the functional phenotype. Using complimentary cellular and biochemical approaches, proteins were tested for effects on GPCR-Gα activation, Gα binding properties, and downstream cAMP levels. Identified intolerant residues with reported cancer-linked mutations RGS14-R173C/H and RGS4-K125Q/E126K, and tolerant RGS14-S127P and RGS10-S64T resulted in a loss-of-function phenotype in GPCR-G protein signaling activity. In downstream cAMP measurement, tolerant RGS14-D137Y and RGS10-S64T and intolerant RGS10-K89M resulted in change of function phenotypes. These findings show that 3DMTR identified intolerant residues that overlap with cancer-linked mutations cause phenotypic changes that negatively impact GPCR-G protein signaling and suggests that 3DMTR is a potentially useful bioinformatics tool for predicting functionally important protein residues. SIGNIFICANCE STATEMENT: Human genetic variant/mutation information has expanded rapidly in recent years, including cancer-linked mutations in regulator of G protein signaling (RGS) proteins. However, experimental testing of the impact of this vast catalogue of mutations on protein function is not feasible. We used the novel bioinformatics tool three-dimensional missense tolerance ratio (3DMTR) to define regions of genetic intolerance in RGS proteins and prioritize which cancer-linked mutants to test. We found that 3DMTR more accurately classifies loss-of-function mutations in RGS proteins than other databases thereby offering a valuable new research tool.
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Affiliation(s)
- Carolina Montañez-Miranda
- Department of Pharmacology and Chemical Biology (C.M.-M., R.E.P., N.H.H., S.R., S.F.T., J.R.H.) and Aflac Cancer and Blood Disorders Center, Department of Pediatrics (J.O.), Emory University School of Medicine, Atlanta, Georgia
| | - Riley E Perszyk
- Department of Pharmacology and Chemical Biology (C.M.-M., R.E.P., N.H.H., S.R., S.F.T., J.R.H.) and Aflac Cancer and Blood Disorders Center, Department of Pediatrics (J.O.), Emory University School of Medicine, Atlanta, Georgia
| | - Nicholas H Harbin
- Department of Pharmacology and Chemical Biology (C.M.-M., R.E.P., N.H.H., S.R., S.F.T., J.R.H.) and Aflac Cancer and Blood Disorders Center, Department of Pediatrics (J.O.), Emory University School of Medicine, Atlanta, Georgia
| | - Jennifer Okalova
- Department of Pharmacology and Chemical Biology (C.M.-M., R.E.P., N.H.H., S.R., S.F.T., J.R.H.) and Aflac Cancer and Blood Disorders Center, Department of Pediatrics (J.O.), Emory University School of Medicine, Atlanta, Georgia
| | - Suneela Ramineni
- Department of Pharmacology and Chemical Biology (C.M.-M., R.E.P., N.H.H., S.R., S.F.T., J.R.H.) and Aflac Cancer and Blood Disorders Center, Department of Pediatrics (J.O.), Emory University School of Medicine, Atlanta, Georgia
| | - Stephen F Traynelis
- Department of Pharmacology and Chemical Biology (C.M.-M., R.E.P., N.H.H., S.R., S.F.T., J.R.H.) and Aflac Cancer and Blood Disorders Center, Department of Pediatrics (J.O.), Emory University School of Medicine, Atlanta, Georgia
| | - John R Hepler
- Department of Pharmacology and Chemical Biology (C.M.-M., R.E.P., N.H.H., S.R., S.F.T., J.R.H.) and Aflac Cancer and Blood Disorders Center, Department of Pediatrics (J.O.), Emory University School of Medicine, Atlanta, Georgia
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6
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Chan KYY, Chung PY, Zhang C, Poon ENY, Leung AWK, Leung KT. R4 RGS proteins as fine tuners of immature and mature hematopoietic cell trafficking. J Leukoc Biol 2022; 112:785-797. [PMID: 35694792 DOI: 10.1002/jlb.1mr0422-475r] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Revised: 04/28/2022] [Indexed: 11/08/2022] Open
Abstract
G-protein-coupled receptors (GPCRs) are the largest and most diverse group of membrane receptors. They are involved in almost every physiologic process and consequently have a pivotal role in an extensive number of pathologies, including genetic, neurologic, and immune system disorders. Indeed, the vast array of GPCRs mechanisms have led to the development of a tremendous number of drug therapies and already account for about a third of marketed drugs. These receptors mediate their downstream signals primarily via G proteins. The regulators of G-protein signaling (RGS) proteins are now in the spotlight as the critical modulatory factors of active GTP-bound Gα subunits of heterotrimeric G proteins to fine-tune the biologic responses driven by the GPCRs. Also, they possess noncanonical functions by multiple mechanisms, such as protein-protein interactions. Essential roles and impacts of these RGS proteins have been revealed in physiology, including hematopoiesis and immunity, and pathologies, including asthma, cancers, and neurologic disorders. This review focuses on the largest subfamily of R4 RGS proteins and provides a brief overview of their structures and G-proteins selectivity. With particular interest, we explore and highlight, their expression in the hematopoietic system and the regulation in the engraftment of hematopoietic stem/progenitor cells (HSPCs). Distinct expression patterns of R4 RGS proteins in the hematopoietic system and their pivotal roles in stem cell trafficking pave the way for realizing new strategies for enhancing the clinical performance of hematopoietic stem cell transplantation. Finally, we discuss the exciting future trends in drug development by targeting RGS activity and expression with small molecules inhibitors and miRNA approaches.
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Affiliation(s)
- Kathy Yuen Yee Chan
- Department of Paediatrics, The Chinese University of Hong Kong, Shatin, Hong Kong, China
| | - Po Yee Chung
- Department of Paediatrics, The Chinese University of Hong Kong, Shatin, Hong Kong, China
| | - Chi Zhang
- Department of Paediatrics, The Chinese University of Hong Kong, Shatin, Hong Kong, China
| | - Ellen Ngar Yun Poon
- School of Biomedical Sciences, The Chinese University of Hong Kong, Shatin, Hong Kong, China
| | - Alex Wing Kwan Leung
- Department of Paediatrics, The Chinese University of Hong Kong, Shatin, Hong Kong, China.,Department of Paediatrics & Adolescent Medicine, Hong Kong Children's Hospital, Hong Kong SAR, China
| | - Kam Tong Leung
- Department of Paediatrics, The Chinese University of Hong Kong, Shatin, Hong Kong, China.,Hong Kong Hub of Paediatric Excellence, The Chinese University of Hong Kong, Shatin, Hong Kong, China
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Shen M, Li T, Feng Y, Chen Z, Dou T, Wu P, Wang K, Lu J, Qu L. Exploring the expression and preliminary function of chicken regulator of G protein signalling 3 ( RGS3) gene in follicular development. Br Poult Sci 2022; 63:613-620. [PMID: 35522181 DOI: 10.1080/00071668.2022.2071597] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
1. The following study explored the expression and preliminary function of RGS3. The spatial and temporal expression patterns of the RGS3 gene were analysed in the ovarian stroma of Shendan No. 6 Green shell hens and Hy-line Brown hens at four time points (6, 28, 40 and 52 weeks old), as well as in various organs and follicles of Hy-line Brown hens.2. Based on the genomic and protein sequences of RGS3 in NCBI database, phylogenetic trees were constructed using MEGA-X. The protein interaction network was analysed using STRING. According to the results of protein-protein interaction network and pathways, the mRNA expression levels of RGS3 and three interaction proteins were explored by qRT-PCR in vitro.3. Spatio-temporal expression data revealed that RGS3 mRNA was expressed in all the organs tested, being highest in the hypothalamus. In different follicles, RGS3 mRNA was highly expressed in post-ovulatory follicles, followed by ovarian stroma and large white follicles. The expression levels of RGS3 mRNA in the ovarian stroma were significantly higher in Shendan No. 6 Green shell hens than that in the Hy-line Brown hens at all egg-laying stages.4. The phylogenetic tree results showed that ducks, geese and chickens had higher homology based on the genomic and protein sequence of RGS3. Moreover, chicken RGS3 interacted with GSK3B, RAF1 and BRAF based on STRING prediction. In vitro follicle stimulating hormone (FSH) treatment showed that mRNA expression levels of RGS3 and those of its predicted interacting proteins BRAF and GSK3B decreased with increasing FSH concentration. The results suggested that RGS3 responds to FSH and may play an important role in the regulation follicular development in chicken.
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Affiliation(s)
- Manman Shen
- College of Biotechnology, Jiangsu University of Science and Technology, Zhenjiang, 225108, China.,Jiangsu Institute of Poultry Science, Chinese Academy of Agricultural Sciences, Yangzhou, 225125, China.,Jiangsu Key Laboratory of Animal genetic Breeding and Molecular Design, College of Animal Science and Technology, Yangzhou University, Yangzhou 225009, China
| | - Tao Li
- College of Biotechnology, Jiangsu University of Science and Technology, Zhenjiang, 225108, China
| | - Yuan Feng
- College of Biotechnology, Jiangsu University of Science and Technology, Zhenjiang, 225108, China
| | - Zikang Chen
- College of Biotechnology, Jiangsu University of Science and Technology, Zhenjiang, 225108, China
| | - Taocun Dou
- Jiangsu Institute of Poultry Science, Chinese Academy of Agricultural Sciences, Yangzhou, 225125, China
| | - Ping Wu
- College of Biotechnology, Jiangsu University of Science and Technology, Zhenjiang, 225108, China
| | - Kehua Wang
- Jiangsu Institute of Poultry Science, Chinese Academy of Agricultural Sciences, Yangzhou, 225125, China
| | - Jian Lu
- Jiangsu Institute of Poultry Science, Chinese Academy of Agricultural Sciences, Yangzhou, 225125, China
| | - Liang Qu
- Jiangsu Institute of Poultry Science, Chinese Academy of Agricultural Sciences, Yangzhou, 225125, China
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Mirabella F, Desiato G, Mancinelli S, Fossati G, Rasile M, Morini R, Markicevic M, Grimm C, Amegandjin C, Termanini A, Peano C, Kunderfranco P, di Cristo G, Zerbi V, Menna E, Lodato S, Matteoli M, Pozzi D. Prenatal interleukin 6 elevation increases glutamatergic synapse density and disrupts hippocampal connectivity in offspring. Immunity 2021; 54:2611-2631.e8. [PMID: 34758338 PMCID: PMC8585508 DOI: 10.1016/j.immuni.2021.10.006] [Citation(s) in RCA: 52] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2020] [Revised: 04/24/2021] [Accepted: 10/07/2021] [Indexed: 02/07/2023]
Abstract
Early prenatal inflammatory conditions are thought to be a risk factor for different neurodevelopmental disorders. Maternal interleukin-6 (IL-6) elevation during pregnancy causes abnormal behavior in offspring, but whether these defects result from altered synaptic developmental trajectories remains unclear. Here we showed that transient IL-6 elevation via injection into pregnant mice or developing embryos enhanced glutamatergic synapses and led to overall brain hyperconnectivity in offspring into adulthood. IL-6 activated synaptogenesis gene programs in glutamatergic neurons and required the transcription factor STAT3 and expression of the RGS4 gene. The STAT3-RGS4 pathway was also activated in neonatal brains during poly(I:C)-induced maternal immune activation, which mimics viral infection during pregnancy. These findings indicate that IL-6 elevation at early developmental stages is sufficient to exert a long-lasting effect on glutamatergic synaptogenesis and brain connectivity, providing a mechanistic framework for the association between prenatal inflammatory events and brain neurodevelopmental disorders.
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Affiliation(s)
- Filippo Mirabella
- Department of Biomedical Sciences, Humanitas University, Via Rita Levi Montalcini 4, 20090 Pieve Emanuele, Milan, Italy; IRCCS Humanitas Research Hospital, via Manzoni 56, 20089 Rozzano, Milan, Italy
| | - Genni Desiato
- IRCCS Humanitas Research Hospital, via Manzoni 56, 20089 Rozzano, Milan, Italy; Institute of Neuroscience - National Research Council, 20139 Milan, Italy
| | - Sara Mancinelli
- IRCCS Humanitas Research Hospital, via Manzoni 56, 20089 Rozzano, Milan, Italy
| | - Giuliana Fossati
- IRCCS Humanitas Research Hospital, via Manzoni 56, 20089 Rozzano, Milan, Italy
| | - Marco Rasile
- Department of Biomedical Sciences, Humanitas University, Via Rita Levi Montalcini 4, 20090 Pieve Emanuele, Milan, Italy
| | - Raffaella Morini
- IRCCS Humanitas Research Hospital, via Manzoni 56, 20089 Rozzano, Milan, Italy
| | - Marija Markicevic
- Neuroscience Center Zürich, ETH Zürich and University of Zürich, Zürich 8057, Switzerland
| | - Christina Grimm
- Neuroscience Center Zürich, ETH Zürich and University of Zürich, Zürich 8057, Switzerland
| | - Clara Amegandjin
- Department of Neurosciences, Université de Montréal, Montréal, QC, Canada; CHU Sainte-Justine Research Center, Montréal, QC, Canada
| | - Alberto Termanini
- Bioinformatic Unit, Humanitas Clinical and Research Center, 20089 Rozzano, Milan, Italy
| | - Clelia Peano
- Institute of Genetic and Biomedical Research, UoS Milan, National Research Council, 20089 Rozzano, Milan, Italy; Genomic Unit, Humanitas Clinical and Research Center, 20089 Rozzano, Milan, Italy
| | - Paolo Kunderfranco
- Bioinformatic Unit, Humanitas Clinical and Research Center, 20089 Rozzano, Milan, Italy
| | - Graziella di Cristo
- Department of Neurosciences, Université de Montréal, Montréal, QC, Canada; CHU Sainte-Justine Research Center, Montréal, QC, Canada
| | - Valerio Zerbi
- Neuroscience Center Zürich, ETH Zürich and University of Zürich, Zürich 8057, Switzerland; Neural Control of Movement Lab, Department of Health Sciences and Technology, ETH Zürich, Zürich 8057, Switzerland
| | - Elisabetta Menna
- IRCCS Humanitas Research Hospital, via Manzoni 56, 20089 Rozzano, Milan, Italy; Institute of Neuroscience - National Research Council, 20139 Milan, Italy
| | - Simona Lodato
- Department of Biomedical Sciences, Humanitas University, Via Rita Levi Montalcini 4, 20090 Pieve Emanuele, Milan, Italy; IRCCS Humanitas Research Hospital, via Manzoni 56, 20089 Rozzano, Milan, Italy
| | - Michela Matteoli
- IRCCS Humanitas Research Hospital, via Manzoni 56, 20089 Rozzano, Milan, Italy; Institute of Neuroscience - National Research Council, 20139 Milan, Italy.
| | - Davide Pozzi
- Department of Biomedical Sciences, Humanitas University, Via Rita Levi Montalcini 4, 20090 Pieve Emanuele, Milan, Italy; IRCCS Humanitas Research Hospital, via Manzoni 56, 20089 Rozzano, Milan, Italy.
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Signaling Pathways Regulated by UBR Box-Containing E3 Ligases. Int J Mol Sci 2021; 22:ijms22158323. [PMID: 34361089 PMCID: PMC8346999 DOI: 10.3390/ijms22158323] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2021] [Revised: 07/28/2021] [Accepted: 07/29/2021] [Indexed: 12/31/2022] Open
Abstract
UBR box E3 ligases, also called N-recognins, are integral components of the N-degron pathway. Representative N-recognins include UBR1, UBR2, UBR4, and UBR5, and they bind destabilizing N-terminal residues, termed N-degrons. Understanding the molecular bases of their substrate recognition and the biological impact of the clearance of their substrates on cellular signaling pathways can provide valuable insights into the regulation of these pathways. This review provides an overview of the current knowledge of the binding mechanism of UBR box N-recognin/N-degron interactions and their roles in signaling pathways linked to G-protein-coupled receptors, apoptosis, mitochondrial quality control, inflammation, and DNA damage. The targeting of these UBR box N-recognins can provide potential therapies to treat diseases such as cancer and neurodegenerative diseases.
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Kankanamge D, Ubeysinghe S, Tennakoon M, Pantula PD, Mitra K, Giri L, Karunarathne A. Dissociation of the G protein βγ from the Gq-PLCβ complex partially attenuates PIP2 hydrolysis. J Biol Chem 2021; 296:100702. [PMID: 33901492 PMCID: PMC8138763 DOI: 10.1016/j.jbc.2021.100702] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2020] [Revised: 04/09/2021] [Accepted: 04/21/2021] [Indexed: 01/14/2023] Open
Abstract
Phospholipase C β (PLCβ), which is activated by the Gq family of heterotrimeric G proteins, hydrolyzes the inner membrane lipid phosphatidylinositol 4,5-bisphosphate (PIP2), generating diacylglycerol and inositol 1,4,5-triphosphate (IP3). Because Gq and PLCβ regulate many crucial cellular processes and have been identified as major disease drivers, activation and termination of PLCβ signaling by the Gαq subunit have been extensively studied. Gq-coupled receptor activation induces intense and transient PIP2 hydrolysis, which subsequently recovers to a low-intensity steady-state equilibrium. However, the molecular underpinnings of this equilibrium remain unclear. Here, we explored the influence of signaling crosstalk between Gq and Gi/o pathways on PIP2 metabolism in living cells using single-cell and optogenetic approaches to spatially and temporally constrain signaling. Our data suggest that the Gβγ complex is a component of the highly efficient lipase GαqGTP-PLCβ-Gβγ. We found that over time, Gβγ dissociates from this lipase complex, leaving the less-efficient GαqGTP-PLCβ lipase complex and allowing the significant partial recovery of PIP2 levels. Our findings also indicate that the subtype of the Gγ subunit in Gβγ fine-tunes the lipase activity of Gq-PLCβ, in which cells expressing Gγ with higher plasma membrane interaction show lower PIP2 recovery. Given that Gγ shows cell- and tissue-specific subtype expression, our findings suggest the existence of tissue-specific distinct Gq-PLCβ signaling paradigms. Furthermore, these results also outline a molecular process that likely safeguards cells from excessive Gq signaling.
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Affiliation(s)
- Dinesh Kankanamge
- Department of Chemistry and Biochemistry, The University of Toledo, Toledo, Ohio, USA
| | - Sithurandi Ubeysinghe
- Department of Chemistry and Biochemistry, The University of Toledo, Toledo, Ohio, USA
| | - Mithila Tennakoon
- Department of Chemistry and Biochemistry, The University of Toledo, Toledo, Ohio, USA
| | - Priyanka Devi Pantula
- Department of Chemical Engineering, Indian Institute of Technology, Hyderabad, Sangareddy, Telangana, India
| | - Kishalay Mitra
- Department of Chemical Engineering, Indian Institute of Technology, Hyderabad, Sangareddy, Telangana, India
| | - Lopamudra Giri
- Department of Chemical Engineering, Indian Institute of Technology, Hyderabad, Sangareddy, Telangana, India
| | - Ajith Karunarathne
- Department of Chemistry and Biochemistry, The University of Toledo, Toledo, Ohio, USA.
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11
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Hariharan A, Weir N, Robertson C, He L, Betsholtz C, Longden TA. The Ion Channel and GPCR Toolkit of Brain Capillary Pericytes. Front Cell Neurosci 2020; 14:601324. [PMID: 33390906 PMCID: PMC7775489 DOI: 10.3389/fncel.2020.601324] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Accepted: 11/13/2020] [Indexed: 12/14/2022] Open
Abstract
Brain pericytes reside on the abluminal surface of capillaries, and their processes cover ~90% of the length of the capillary bed. These cells were first described almost 150 years ago (Eberth, 1871; Rouget, 1873) and have been the subject of intense experimental scrutiny in recent years, but their physiological roles remain uncertain and little is known of the complement of signaling elements that they employ to carry out their functions. In this review, we synthesize functional data with single-cell RNAseq screens to explore the ion channel and G protein-coupled receptor (GPCR) toolkit of mesh and thin-strand pericytes of the brain, with the aim of providing a framework for deeper explorations of the molecular mechanisms that govern pericyte physiology. We argue that their complement of channels and receptors ideally positions capillary pericytes to play a central role in adapting blood flow to meet the challenge of satisfying neuronal energy requirements from deep within the capillary bed, by enabling dynamic regulation of their membrane potential to influence the electrical output of the cell. In particular, we outline how genetic and functional evidence suggest an important role for Gs-coupled GPCRs and ATP-sensitive potassium (KATP) channels in this context. We put forth a predictive model for long-range hyperpolarizing electrical signaling from pericytes to upstream arterioles, and detail the TRP and Ca2+ channels and Gq, Gi/o, and G12/13 signaling processes that counterbalance this. We underscore critical questions that need to be addressed to further advance our understanding of the signaling topology of capillary pericytes, and how this contributes to their physiological roles and their dysfunction in disease.
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Affiliation(s)
- Ashwini Hariharan
- Department of Physiology, School of Medicine, University of Maryland, Baltimore, MD, United States
| | - Nick Weir
- Department of Physiology, School of Medicine, University of Maryland, Baltimore, MD, United States
| | - Colin Robertson
- Department of Physiology, School of Medicine, University of Maryland, Baltimore, MD, United States
| | - Liqun He
- Rudbeck Laboratory, Department of Immunology, Genetics and Pathology, Uppsala University, Uppsala, Sweden
| | - Christer Betsholtz
- Rudbeck Laboratory, Department of Immunology, Genetics and Pathology, Uppsala University, Uppsala, Sweden.,Department of Medicine Huddinge (MedH), Karolinska Institutet & Integrated Cardio Metabolic Centre, Huddinge, Sweden
| | - Thomas A Longden
- Department of Physiology, School of Medicine, University of Maryland, Baltimore, MD, United States
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12
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Layeghi-Ghalehsoukhteh S, Pal Choudhuri S, Ocal O, Zolghadri Y, Pashkov V, Niederstrasser H, Posner BA, Kantheti HS, Azevedo-Pouly AC, Huang H, Girard L, MacDonald RJ, Brekken RA, Wilkie TM. Concerted cell and in vivo screen for pancreatic ductal adenocarcinoma (PDA) chemotherapeutics. Sci Rep 2020; 10:20662. [PMID: 33244070 PMCID: PMC7693321 DOI: 10.1038/s41598-020-77373-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2020] [Accepted: 10/23/2020] [Indexed: 12/22/2022] Open
Abstract
PDA is a major cause of US cancer-related deaths. Oncogenic Kras presents in 90% of human PDAs. Kras mutations occur early in pre-neoplastic lesions but are insufficient to cause PDA. Other contributing factors early in disease progression include chronic pancreatitis, alterations in epigenetic regulators, and tumor suppressor gene mutation. GPCRs activate heterotrimeric G-proteins that stimulate intracellular calcium and oncogenic Kras signaling, thereby promoting pancreatitis and progression to PDA. By contrast, Rgs proteins inhibit Gi/q-coupled GPCRs to negatively regulate PDA progression. Rgs16::GFP is expressed in response to caerulein-induced acinar cell dedifferentiation, early neoplasia, and throughout PDA progression. In genetically engineered mouse models of PDA, Rgs16::GFP is useful for pre-clinical rapid in vivo validation of novel chemotherapeutics targeting early lesions in patients following successful resection or at high risk for progressing to PDA. Cultured primary PDA cells express Rgs16::GFP in response to cytotoxic drugs. A histone deacetylase inhibitor, TSA, stimulated Rgs16::GFP expression in PDA primary cells, potentiated gemcitabine and JQ1 cytotoxicity in cell culture, and Gem + TSA + JQ1 inhibited tumor initiation and progression in vivo. Here we establish the use of Rgs16::GFP expression for testing drug combinations in cell culture and validation of best candidates in our rapid in vivo screen.
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Affiliation(s)
- Somayeh Layeghi-Ghalehsoukhteh
- Department of Pharmacology, UT Southwestern Medical Center, 6001 Forest Park Drive, Dallas, TX, 75390, USA
- Department of Basic Science, School of Veterinary Medicine, Shiraz University, Shiraz, Iran
| | - Shreoshi Pal Choudhuri
- Department of Pharmacology, UT Southwestern Medical Center, 6001 Forest Park Drive, Dallas, TX, 75390, USA
| | - Ozhan Ocal
- Department of Pharmacology, UT Southwestern Medical Center, 6001 Forest Park Drive, Dallas, TX, 75390, USA
- Department of Molecular Biology and Genetics, Bilkent University, 06800, Ankara, Turkey
| | - Yalda Zolghadri
- Department of Pharmacology, UT Southwestern Medical Center, 6001 Forest Park Drive, Dallas, TX, 75390, USA
- Department of Basic Science, School of Veterinary Medicine, Shiraz University, Shiraz, Iran
| | - Victor Pashkov
- Department of Pharmacology, UT Southwestern Medical Center, 6001 Forest Park Drive, Dallas, TX, 75390, USA
| | - Hanspeter Niederstrasser
- Department of Biochemistry, UT Southwestern Medical Center, 5323 Harry Hines Blvd, Dallas, TX, 75390, USA
| | - Bruce A Posner
- Department of Biochemistry, UT Southwestern Medical Center, 5323 Harry Hines Blvd, Dallas, TX, 75390, USA
| | - Havish S Kantheti
- Department of Pharmacology, UT Southwestern Medical Center, 6001 Forest Park Drive, Dallas, TX, 75390, USA
- Cancer Discovery (CanDisc) Group, UT Southwestern Medical Center, 6001 Forest Park Drive, Dallas, TX, 75390, USA
| | - Ana C Azevedo-Pouly
- Department of Surgery, University of Arkansas for Medical Sciences, Little Rock, AR, USA
| | - Huocong Huang
- Hamon Center for Therapeutic Oncology Research, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Luc Girard
- Department of Pharmacology, UT Southwestern Medical Center, 6001 Forest Park Drive, Dallas, TX, 75390, USA
- Hamon Center for Therapeutic Oncology Research, University of Texas Southwestern Medical Center, Dallas, TX, USA
- Simmons Comprehensive Cancer Center, University of Texas Southwestern Medical Center, Dallas, TX, 75390, USA
| | - Raymond J MacDonald
- Department of Molecular Biology, UT Southwestern Medical Center, 5323 Harry Hines Blvd, Dallas, TX, 75390, USA
| | - Rolf A Brekken
- Hamon Center for Therapeutic Oncology Research, University of Texas Southwestern Medical Center, Dallas, TX, USA
- Department of Surgery, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Thomas M Wilkie
- Department of Pharmacology, UT Southwestern Medical Center, 6001 Forest Park Drive, Dallas, TX, 75390, USA.
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13
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Masuho I, Balaji S, Muntean BS, Skamangas NK, Chavali S, Tesmer JJG, Babu MM, Martemyanov KA. A Global Map of G Protein Signaling Regulation by RGS Proteins. Cell 2020; 183:503-521.e19. [PMID: 33007266 PMCID: PMC7572916 DOI: 10.1016/j.cell.2020.08.052] [Citation(s) in RCA: 73] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2019] [Revised: 07/03/2020] [Accepted: 08/29/2020] [Indexed: 12/24/2022]
Abstract
The control over the extent and timing of G protein signaling is provided by the regulator of G protein signaling (RGS) proteins that deactivate G protein α subunits (Gα). Mammalian genomes encode 20 canonical RGS and 16 Gα genes with key roles in physiology and disease. To understand the principles governing the selectivity of Gα regulation by RGS, we examine the catalytic activity of all canonical human RGS proteins and their selectivity for a complete set of Gα substrates using real-time kinetic measurements in living cells. The data reveal rules governing RGS-Gα recognition, the structural basis of its selectivity, and provide principles for engineering RGS proteins with defined selectivity. The study also explores the evolution of RGS-Gα selectivity through ancestral reconstruction and demonstrates how naturally occurring non-synonymous variants in RGS alter signaling. These results provide a blueprint for decoding signaling selectivity and advance our understanding of molecular recognition principles. Systematic analysis reveals G protein selectivity of all canonical RGS proteins RGS proteins rely on selectivity bar codes for selective G protein recognition Transplantation of bar codes across RGS proteins switches their G protein preferences Natural variants, mutations, and evolution shape RGS selectivity
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Affiliation(s)
- Ikuo Masuho
- Department of Neuroscience, The Scripps Research Institute Florida, Jupiter, FL 33458, USA
| | - Santhanam Balaji
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge CB2 0QH, UK; Departments of Structural Biology and Center for Data Driven Discovery, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - Brian S Muntean
- Department of Neuroscience, The Scripps Research Institute Florida, Jupiter, FL 33458, USA
| | - Nickolas K Skamangas
- Department of Neuroscience, The Scripps Research Institute Florida, Jupiter, FL 33458, USA
| | - Sreenivas Chavali
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge CB2 0QH, UK; Department of Biology, Indian Institute of Science Education and Research (IISER) Tirupati, Karakambadi Road, Tirupati 517 507, India
| | - John J G Tesmer
- Departments of Biological Sciences and Medicinal Chemistry and Molecular Pharmacology, Purdue University, West Lafayette, IN 47907-2054, USA
| | - M Madan Babu
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge CB2 0QH, UK; Departments of Structural Biology and Center for Data Driven Discovery, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - Kirill A Martemyanov
- Department of Neuroscience, The Scripps Research Institute Florida, Jupiter, FL 33458, USA.
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14
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Regulators of G protein signalling as pharmacological targets for the treatment of neuropathic pain. Pharmacol Res 2020; 160:105148. [PMID: 32858121 DOI: 10.1016/j.phrs.2020.105148] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/31/2019] [Revised: 07/24/2020] [Accepted: 08/10/2020] [Indexed: 12/30/2022]
Abstract
Neuropathic pain, a specific type of chronic pain resulting from persistent nervous tissue lesions, is a debilitating condition that affects about 7% of the population. This condition remains particularly difficult to treat because of the poor understanding of its underlying mechanisms. Drugs currently used to alleviate this chronic pain syndrome are of limited benefit due to their lack of efficacy and the elevated risk of side effects, especially after a prolonged period of treatment. Although drugs targeting G protein-coupled receptors (GPCR) also have several limitations, such as progressive loss of efficacy due to receptor desensitization or unavoidable side effects due to wide receptor distribution, the identification of several molecular partners that contribute to the fine-tuning of receptor activity has raised new opportunities for the development of alternative therapeutic approaches. Regulators of G protein signalling (RGS) act intracellularly by influencing the coupling process and activity of G proteins, and are amongst the best-characterized physiological modulators of GPCR. Changes in RGS expression have been documented in a range of models of neuropathic pain, or after prolonged treatment with diverse analgesics, and could participate in altered pain processing as well as impaired physiological or pharmacological control of nociceptive signals. The present review summarizes the experimental data that implicates RGS in the development of pain with focus on the pathological mechanisms of neuropathic pain, including the impact of neuropathic lesions on RGS expression and, reciprocally, the influence of modifying RGS on GPCRs involved in the modulation of nociception as well as on the outcome of pain. In this context, we address the question of the relevance of RGS as promising targets in the treatment of neuropathic pain.
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15
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Zmijewska A, Czelejewska W, Waszkiewicz EM, Gajewska A, Okrasa S, Franczak A. Transcriptomic analysis of the porcine anterior pituitary gland during the peri-implantation period. Reprod Domest Anim 2020; 55:1434-1445. [PMID: 32745313 DOI: 10.1111/rda.13794] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2020] [Accepted: 07/28/2020] [Indexed: 12/21/2022]
Abstract
The peri-implantation period is controlled by signals originating from hypothalamic-pituitary-ovarian axis, uterus and developing embryos. The transcriptomic activity of the anterior pituitary gland may be important for the control of the peri-implantation period. The aim of this study was to determine the alternations in the transcriptomic profile of porcine anterior pituitary gland during the peri-implantation period (days 15-16 of pregnancy) in comparison with established for the respective days of the oestrous cycle. Analysis using a microarray approach indicated that the 651 genes (fold-change ˂1.2; p ≤ .05) were differentially expressed (DEGs) in the anterior pituitary of pigs during the peri-implantation period when compared to cyclic females. Of these DEGs, 404 were upregulated and 247 downregulated. Analysis of occurred relationships among DEGs revealed that some of them are involved in steroid-response and oestrogen synthesis, FSH secretion, immune response, PPAR signalling pathway and the potential for DNA methylation. In conclusion, the altered transcriptomic profile of the porcine pituitary gland in pigs during the peri-implantation period indicates the role of embryos presence in the creation of transcriptomic activity of the pituitary gland in pigs.
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Affiliation(s)
- Agata Zmijewska
- Department of Animal Anatomy and Physiology, Faculty of Biology and Biotechnology, University of Warmia and Mazury in Olsztyn, Olsztyn, Poland
| | - Wioleta Czelejewska
- Department of Animal Anatomy and Physiology, Faculty of Biology and Biotechnology, University of Warmia and Mazury in Olsztyn, Olsztyn, Poland
| | - Ewa M Waszkiewicz
- Department of Animal Anatomy and Physiology, Faculty of Biology and Biotechnology, University of Warmia and Mazury in Olsztyn, Olsztyn, Poland
| | - Alina Gajewska
- Department of Animal Physiology, The Kielanowski Institute of Animal Physiology and Nutrition, Polish Academy of Science, Jablonna, Poland
| | - Stanislaw Okrasa
- Department of Animal Anatomy and Physiology, Faculty of Biology and Biotechnology, University of Warmia and Mazury in Olsztyn, Olsztyn, Poland
| | - Anita Franczak
- Department of Animal Anatomy and Physiology, Faculty of Biology and Biotechnology, University of Warmia and Mazury in Olsztyn, Olsztyn, Poland
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16
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Wong GS, Redes JL, Balenga N, McCullough M, Fuentes N, Gokhale A, Koziol-White C, Jude JA, Madigan LA, Chan EC, Jester WH, Biardel S, Flamand N, Panettieri RA, Druey KM. RGS4 promotes allergen- and aspirin-associated airway hyperresponsiveness by inhibiting PGE2 biosynthesis. J Allergy Clin Immunol 2020; 146:1152-1164.e13. [PMID: 32199913 DOI: 10.1016/j.jaci.2020.03.004] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2019] [Revised: 02/21/2020] [Accepted: 03/11/2020] [Indexed: 12/12/2022]
Abstract
BACKGROUND Allergens elicit host production of mediators acting on G-protein-coupled receptors to regulate airway tone. Among these is prostaglandin E2 (PGE2), which, in addition to its role as a bronchodilator, has anti-inflammatory actions. Some patients with asthma develop bronchospasm after the ingestion of aspirin and other nonsteroidal anti-inflammatory drugs, a disorder termed aspirin-exacerbated respiratory disease. This condition may result in part from abnormal dependence on the bronchoprotective actions of PGE2. OBJECTIVE We sought to understand the functions of regulator of G protein signaling 4 (RGS4), a cytoplasmic protein expressed in airway smooth muscle and bronchial epithelium that regulates the activity of G-protein-coupled receptors, in asthma. METHODS We examined RGS4 expression in human lung biopsies by immunohistochemistry. We assessed airways hyperresponsiveness (AHR) and lung inflammation in germline and airway smooth muscle-specific Rgs4-/- mice and in mice treated with an RGS4 antagonist after challenge with Aspergillus fumigatus. We examined the role of RGS4 in nonsteroidal anti-inflammatory drug-associated bronchoconstriction by challenging aspirin-exacerbated respiratory disease-like (ptges1-/-) mice with aspirin. RESULTS RGS4 expression in respiratory epithelium is increased in subjects with severe asthma. Allergen-induced AHR was unexpectedly diminished in Rgs4-/- mice, a finding associated with increased airway PGE2 levels. RGS4 modulated allergen-induced PGE2 secretion in human bronchial epithelial cells and prostanoid-dependent bronchodilation. The RGS4 antagonist CCG203769 attenuated AHR induced by allergen or aspirin challenge of wild-type or ptges1-/- mice, respectively, in association with increased airway PGE2 levels. CONCLUSIONS RGS4 may contribute to the development of AHR by reducing airway PGE2 biosynthesis in allergen- and aspirin-induced asthma.
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Affiliation(s)
- Gordon S Wong
- Lung and Vascular Inflammation Section, Laboratory of Allergic Diseases, National Institute of Allergy and Infectious Diseases (NIAID)/National Institutes of Health (NIH), Bethesda, Md
| | - Jamie L Redes
- Lung and Vascular Inflammation Section, Laboratory of Allergic Diseases, National Institute of Allergy and Infectious Diseases (NIAID)/National Institutes of Health (NIH), Bethesda, Md
| | - Nariman Balenga
- Lung and Vascular Inflammation Section, Laboratory of Allergic Diseases, National Institute of Allergy and Infectious Diseases (NIAID)/National Institutes of Health (NIH), Bethesda, Md
| | - Morgan McCullough
- Lung and Vascular Inflammation Section, Laboratory of Allergic Diseases, National Institute of Allergy and Infectious Diseases (NIAID)/National Institutes of Health (NIH), Bethesda, Md
| | - Nathalie Fuentes
- Lung and Vascular Inflammation Section, Laboratory of Allergic Diseases, National Institute of Allergy and Infectious Diseases (NIAID)/National Institutes of Health (NIH), Bethesda, Md
| | - Ameya Gokhale
- Food Allergy Research Unit, Laboratory of Allergic Diseases, NIAID/NIH, Bethesda, Md
| | - Cynthia Koziol-White
- Rutgers Institute for Translational Medicine and Science, Child Health Institute of New Jersey, Rutgers University School of Medicine, New Brunswick, NJ
| | - Joseph A Jude
- Rutgers Institute for Translational Medicine and Science, Child Health Institute of New Jersey, Rutgers University School of Medicine, New Brunswick, NJ
| | - Laura A Madigan
- Lung and Vascular Inflammation Section, Laboratory of Allergic Diseases, National Institute of Allergy and Infectious Diseases (NIAID)/National Institutes of Health (NIH), Bethesda, Md
| | - Eunice C Chan
- Lung and Vascular Inflammation Section, Laboratory of Allergic Diseases, National Institute of Allergy and Infectious Diseases (NIAID)/National Institutes of Health (NIH), Bethesda, Md
| | - William H Jester
- Rutgers Institute for Translational Medicine and Science, Child Health Institute of New Jersey, Rutgers University School of Medicine, New Brunswick, NJ
| | - Sabrina Biardel
- Centre de recherche de l'IUCPQ, Département de médecine, Faculté de médecine, Université Laval, Québec, Canada
| | - Nicolas Flamand
- Centre de recherche de l'IUCPQ, Département de médecine, Faculté de médecine, Université Laval, Québec, Canada
| | - Reynold A Panettieri
- Rutgers Institute for Translational Medicine and Science, Child Health Institute of New Jersey, Rutgers University School of Medicine, New Brunswick, NJ
| | - Kirk M Druey
- Lung and Vascular Inflammation Section, Laboratory of Allergic Diseases, National Institute of Allergy and Infectious Diseases (NIAID)/National Institutes of Health (NIH), Bethesda, Md.
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17
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Senese NB, Kandasamy R, Kochan KE, Traynor JR. Regulator of G-Protein Signaling (RGS) Protein Modulation of Opioid Receptor Signaling as a Potential Target for Pain Management. Front Mol Neurosci 2020; 13:5. [PMID: 32038168 PMCID: PMC6992652 DOI: 10.3389/fnmol.2020.00005] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2019] [Accepted: 01/09/2020] [Indexed: 12/23/2022] Open
Abstract
Opioid drugs are the gold standard for the management of pain, but their use is severely limited by dangerous and unpleasant side effects. All clinically available opioid analgesics bind to and activate the mu-opioid receptor (MOR), a heterotrimeric G-protein-coupled receptor, to produce analgesia. The activity of these receptors is modulated by a family of intracellular RGS proteins or regulators of G-protein signaling proteins, characterized by the presence of a conserved RGS Homology (RH) domain. These proteins act as negative regulators of G-protein signaling by serving as GTPase accelerating proteins or GAPS to switch off signaling by both the Gα and βγ subunits of heterotrimeric G-proteins. Consequently, knockdown or knockout of RGS protein activity enhances signaling downstream of MOR. In this review we discuss current knowledge of how this activity, across the different families of RGS proteins, modulates MOR activity, as well as activity of other members of the opioid receptor family, and so pain and analgesia in animal models, with particular emphasis on RGS4 and RGS9 families. We discuss inhibition of RGS proteins with small molecule inhibitors that bind to sensitive cysteine moieties in the RH domain and the potential for targeting this family of intracellular proteins as adjuncts to provide an opioid sparing effect or as standalone analgesics by promoting the activity of endogenous opioid peptides. Overall, we conclude that RGS proteins may be a novel drug target to provide analgesia with reduced opioid-like side effects, but that much basic work is needed to define the roles for specific RGS proteins, particularly in chronic pain, as well as a need to develop newer inhibitors.
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Affiliation(s)
- Nicolas B Senese
- Department of Pharmacology, Edward F. Domino Research Center, University of Michigan Medical School, Ann Arbor, MI, United States.,Department of Psychiatry, Chicago, IL, United States
| | - Ram Kandasamy
- Department of Pharmacology, Edward F. Domino Research Center, University of Michigan Medical School, Ann Arbor, MI, United States.,Department of Psychology, California State University, East Bay, Hayward, CA, United States
| | - Kelsey E Kochan
- Department of Pharmacology, Edward F. Domino Research Center, University of Michigan Medical School, Ann Arbor, MI, United States
| | - John R Traynor
- Department of Pharmacology, Edward F. Domino Research Center, University of Michigan Medical School, Ann Arbor, MI, United States.,Department of Medicinal Chemistry, College of Pharmacy, University of Michigan, Ann Arbor, MI, United States
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18
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The Emerging Role of Gβ Subunits in Human Genetic Diseases. Cells 2019; 8:cells8121567. [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] [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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19
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Echeverría E, Velez Rueda AJ, Cabrera M, Juritz E, Burghi V, Fabián L, Davio C, Lorenzano Menna P, Fernández NC. Identification of inhibitors of the RGS homology domain of GRK2 by docking-based virtual screening. Life Sci 2019; 239:116872. [DOI: 10.1016/j.lfs.2019.116872] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2019] [Revised: 09/10/2019] [Accepted: 09/11/2019] [Indexed: 01/25/2023]
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20
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Luo Z, Ahlers-Dannen KE, Spicer MM, Yang J, Alberico S, Stevens HE, Narayanan NS, Fisher RA. Age-dependent nigral dopaminergic neurodegeneration and α-synuclein accumulation in RGS6-deficient mice. JCI Insight 2019; 5:126769. [PMID: 31120439 DOI: 10.1172/jci.insight.126769] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Parkinson's is primarily a non-familial, age-related disorder caused by α-synuclein accumulation and the progressive loss of dopamine neurons in the substantia nigra pars compacta (SNc). G protein-coupled receptor (GPCR)-cAMP signaling has been linked to a reduction in human Parkinson's incidence and α-synuclein expression. Neuronal cAMP levels are controlled by GPCRs coupled to Gs or Gi/o, which increase or decrease cAMP, respectively. Regulator of G protein signaling 6 (RGS6) powerfully inhibits Gi/o signaling. Therefore, we hypothesized that RGS6 suppresses D2 autoreceptor- Gi/o signaling in SNc dopamine neurons promoting neuronal survival and reducing α-synuclein expression. Here we provide novel evidence that RGS6 critically suppresses late-age-onset SNc dopamine neuron loss and α-synuclein accumulation. RGS6 is restrictively expressed in human SNc dopamine neurons and, despite their loss in Parkinson's, all surviving neurons express RGS6. RGS6-/- mice exhibit hyperactive D2 autoreceptors with reduced cAMP signaling in SNc dopamine neurons. Importantly, RGS6-/- mice recapitulate key sporadic Parkinson's hallmarks, including: SNc dopamine neuron loss, reduced nigrostriatal dopamine, motor deficits, and α-synuclein accumulation. To our knowledge, Rgs6 is the only gene whose loss phenocopies these features of human Parkinson's. Therefore, RGS6 is a key regulator of D2R-Gi/o signaling in SNc dopamine neurons, protecting against Parkinson's neurodegeneration and α-synuclein accumulation.
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Affiliation(s)
- Zili Luo
- Department of Pharmacology, University of Iowa Carver College of Medicine, Iowa City, Iowa, USA
| | - Katelin E Ahlers-Dannen
- Department of Pharmacology, University of Iowa Carver College of Medicine, Iowa City, Iowa, USA
| | - Mackenzie M Spicer
- Department of Pharmacology, University of Iowa Carver College of Medicine, Iowa City, Iowa, USA.,Interdisciplinary Graduate Program of Molecular Medicine, University of Iowa Carver College of Medicine, Iowa City, Iowa, USA
| | - Jianqi Yang
- Department of Pharmacology, University of Iowa Carver College of Medicine, Iowa City, Iowa, USA
| | | | - Hanna E Stevens
- Department of Psychiatry, University of Iowa Carver College of Medicine, Iowa City, Iowa, USA
| | - Nandakumar S Narayanan
- Department of Neurology, University of Iowa Carver College of Medicine, Iowa City, Iowa, USA
| | - Rory A Fisher
- Department of Pharmacology, University of Iowa Carver College of Medicine, Iowa City, Iowa, USA
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21
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Navot S, Kosloff M. Structural design principles that underlie the multi-specific interactions of Gα q with dissimilar partners. Sci Rep 2019; 9:6898. [PMID: 31053791 PMCID: PMC6499889 DOI: 10.1038/s41598-019-43395-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2019] [Accepted: 04/23/2019] [Indexed: 02/07/2023] Open
Abstract
Gαq is a ubiquitous molecular switch that activates the effectors phospholipase-C-β3 (PLC-β3) and Rho guanine-nucleotide exchange factors. Gαq is inactivated by regulators of G protein signaling proteins, as well as by PLC-β3. Gαq further interacts with G protein-coupled receptor kinase 2 (GRK2), although the functional role of this interaction is debated. While X-ray structures of Gαq bound to representatives of these partners have revealed details of their interactions, the mechanistic basis for differential Gαq interactions with multiple partners (i.e., Gαq multi-specificity) has not been elucidated at the individual residue resolution. Here, we map the structural determinants of Gαq multi-specificity using structure-based energy calculations. We delineate regions that specifically interact with GTPase Activating Proteins (GAPs) and residues that exclusively contribute to effector interactions, showing that only the Gαq “Switch II” region interacts with all partners. Our analysis further suggests that Gαq-GRK2 interactions are consistent with GRK2 functioning as an effector, rather than a GAP. Our multi-specificity analysis pinpoints Gαq residues that uniquely contribute to interactions with particular partners, enabling precise manipulation of these cascades. As such, we dissect the molecular basis of Gαq function as a central signaling hub, which can be used to target Gαq-mediated signaling in therapeutic interventions.
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Affiliation(s)
- Shir Navot
- The Department of Human Biology, Faculty of Natural Science, University of Haifa, Haifa, 3498838, Israel
| | - Mickey Kosloff
- The Department of Human Biology, Faculty of Natural Science, University of Haifa, Haifa, 3498838, Israel.
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22
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Squires KE, Montañez-Miranda C, Pandya RR, Torres MP, Hepler JR. Genetic Analysis of Rare Human Variants of Regulators of G Protein Signaling Proteins and Their Role in Human Physiology and Disease. Pharmacol Rev 2018; 70:446-474. [PMID: 29871944 DOI: 10.1124/pr.117.015354] [Citation(s) in RCA: 49] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Regulators of G protein signaling (RGS) proteins modulate the physiologic actions of many neurotransmitters, hormones, and other signaling molecules. Human RGS proteins comprise a family of 20 canonical proteins that bind directly to G protein-coupled receptors/G protein complexes to limit the lifetime of their signaling events, which regulate all aspects of cell and organ physiology. Genetic variations account for diverse human traits and individual predispositions to disease. RGS proteins contribute to many complex polygenic human traits and pathologies such as hypertension, atherosclerosis, schizophrenia, depression, addiction, cancers, and many others. Recent analysis indicates that most human diseases are due to extremely rare genetic variants. In this study, we summarize physiologic roles for RGS proteins and links to human diseases/traits and report rare variants found within each human RGS protein exome sequence derived from global population studies. Each RGS sequence is analyzed using recently described bioinformatics and proteomic tools for measures of missense tolerance ratio paired with combined annotation-dependent depletion scores, and protein post-translational modification (PTM) alignment cluster analysis. We highlight selected variants within the well-studied RGS domain that likely disrupt RGS protein functions and provide comprehensive variant and PTM data for each RGS protein for future study. We propose that rare variants in functionally sensitive regions of RGS proteins confer profound change-of-function phenotypes that may contribute, in newly appreciated ways, to complex human diseases and/or traits. This information provides investigators with a valuable database to explore variation in RGS protein function, and for targeting RGS proteins as future therapeutic targets.
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Affiliation(s)
- Katherine E Squires
- Department of Pharmacology, Emory University School of Medicine, Atlanta, Georgia (K.E.S., C.M.-M., J.R.H.); and School of Biological Sciences, Georgia Institute of Technology, Atlanta, Georgia (R.R.P., M.P.T.)
| | - Carolina Montañez-Miranda
- Department of Pharmacology, Emory University School of Medicine, Atlanta, Georgia (K.E.S., C.M.-M., J.R.H.); and School of Biological Sciences, Georgia Institute of Technology, Atlanta, Georgia (R.R.P., M.P.T.)
| | - Rushika R Pandya
- Department of Pharmacology, Emory University School of Medicine, Atlanta, Georgia (K.E.S., C.M.-M., J.R.H.); and School of Biological Sciences, Georgia Institute of Technology, Atlanta, Georgia (R.R.P., M.P.T.)
| | - Matthew P Torres
- Department of Pharmacology, Emory University School of Medicine, Atlanta, Georgia (K.E.S., C.M.-M., J.R.H.); and School of Biological Sciences, Georgia Institute of Technology, Atlanta, Georgia (R.R.P., M.P.T.)
| | - John R Hepler
- Department of Pharmacology, Emory University School of Medicine, Atlanta, Georgia (K.E.S., C.M.-M., J.R.H.); and School of Biological Sciences, Georgia Institute of Technology, Atlanta, Georgia (R.R.P., M.P.T.)
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23
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Wirth S, Kunert M, Ahrens LM, Krause K, Broska S, Paetz C, Kniemeyer O, Jung EM, Boland W, Kothe E. The regulator of G-protein signalling Thn1 links pheromone response to volatile production in Schizophyllum commune. Environ Microbiol 2018; 20:3684-3699. [PMID: 30062773 DOI: 10.1111/1462-2920.14369] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2017] [Revised: 07/13/2018] [Accepted: 07/27/2018] [Indexed: 01/07/2023]
Abstract
The regulator of G-protein signalling, Thn1, is involved in sexual development through pheromone signalling in the mushroom forming basidiomycete Schizophyllum commune affecting hyphal morphology and mating interactions. Thn1 plays a key role in coordinating sesquiterpene production, pheromone response and sexual development. The gene thn1 is transcriptionally regulated in response to mating with a role in clamp cell development and hydrophobin gene transcription. Further, it negatively regulates cAMP signalling and secondary metabolism. Disruption of thn1 affects dikaryotization by reducing clamp fusion and development with predominant non-fused pseudoclamps. Enhanced protein kinase A (PKA) activities in Δthn1 strains indicate that Thn1 regulates pheromone signalling by de-activating G-protein α subunits, which control cAMP-dependent PKA. The repressed formation of aerial hyphae could be linked to a reduced metabolic activity and to a transcriptional down-regulation of hyd6 and sc3 hydrophobin genes. Thn1 was also shown to be necessary for the biosynthesis of sesquiterpenes and an altered spectrum of sesquiterpenes in Δthn1 is linked to transcriptional up-regulation of biosynthesis genes. Proteome analysis indicated changes in cytoskeletal structure affecting actin localization, linking the major regulator Thn1 to growth and development of S. commune. The results support a role for Thn1 in G-protein signalling connecting development and secondary metabolism.
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Affiliation(s)
- Sophia Wirth
- Friedrich Schiller University Jena, Institute of Microbiology, Microbial Communication, Neugasse 25, 07743, Jena, Germany
| | - Maritta Kunert
- Max Planck Institute for Chemical Ecology, Bioorganic Chemistry, Hans-Knöll-Straße 8, 07745, Jena, Germany
| | - Lisa-Marija Ahrens
- Friedrich Schiller University Jena, Institute of Microbiology, Microbial Communication, Neugasse 25, 07743, Jena, Germany
| | - Katrin Krause
- Friedrich Schiller University Jena, Institute of Microbiology, Microbial Communication, Neugasse 25, 07743, Jena, Germany
| | - Selina Broska
- Friedrich Schiller University Jena, Institute of Microbiology, Microbial Communication, Neugasse 25, 07743, Jena, Germany
| | - Christian Paetz
- Max Planck Institute for Chemical Ecology, Bioorganic Chemistry, Hans-Knöll-Straße 8, 07745, Jena, Germany
| | - Olaf Kniemeyer
- Leibnitz Institute for Natural Product Research and Infection Biology - Hans Knöll Institute, Molecular and Applied Microbiology, Adolf-Reichwein-Straße 23, 07745, Jena, Germany
| | - Elke-Martina Jung
- Friedrich Schiller University Jena, Institute of Microbiology, Microbial Communication, Neugasse 25, 07743, Jena, Germany
| | - Wilhelm Boland
- Max Planck Institute for Chemical Ecology, Bioorganic Chemistry, Hans-Knöll-Straße 8, 07745, Jena, Germany
| | - Erika Kothe
- Friedrich Schiller University Jena, Institute of Microbiology, Microbial Communication, Neugasse 25, 07743, Jena, Germany
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24
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Chan EC, Ren C, Xie Z, Jude J, Barker T, Koziol-White CA, Ma M, Panettieri RA, Wu D, Rosenberg HF, Druey KM. Regulator of G protein signaling 5 restricts neutrophil chemotaxis and trafficking. J Biol Chem 2018; 293:12690-12702. [PMID: 29929985 DOI: 10.1074/jbc.ra118.002404] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2018] [Revised: 06/14/2018] [Indexed: 01/09/2023] Open
Abstract
Neutrophils are white blood cells that are mobilized to damaged tissues and to sites of pathogen invasion, providing the first line of host defense. Chemokines displayed on the surface of blood vessels promote migration of neutrophils to these sites, and tissue- and pathogen-derived chemoattractant signals, including N-formylmethionylleucylphenylalanine (fMLP), elicit further migration to sites of infection. Although nearly all chemoattractant receptors use heterotrimeric G proteins to transmit signals, many of the mechanisms lying downstream of chemoattractant receptors that either promote or limit neutrophil motility are incompletely defined. Here, we show that regulator of G protein signaling 5 (RGS5), a protein that modulates G protein activity, is expressed in both human and murine neutrophils. We detected significantly more neutrophils in the airways of Rgs5-/- mice than WT counterparts following acute respiratory virus infection and in the peritoneum in response to injection of thioglycollate, a biochemical proinflammatory stimulus. RGS5-deficient neutrophils responded with increased chemotaxis elicited by the chemokines CXC motif chemokine ligand 1 (CXCL1), CXCL2, and CXCL12 but not fMLP. Moreover, adhesion of these cells was increased in the presence of both CXCL2 and fMLP. In summary, our results indicate that RGS5 deficiency increases chemotaxis and adhesion, leading to more efficient neutrophil mobilization to inflamed tissues in mice. These findings suggest that RGS5 expression and activity in neutrophils determine their migrational patterns in the complex microenvironments characteristic of inflamed tissues.
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Affiliation(s)
- Eunice C Chan
- Molecular Signal Transduction Section, NIAID, National Institutes of Health, Bethesda, Maryland 20892
| | - Chunguang Ren
- Department of Pharmacology, Yale University School of Medicine, New Haven, Connecticut 06510
| | - Zhihui Xie
- Molecular Signal Transduction Section, NIAID, National Institutes of Health, Bethesda, Maryland 20892
| | - Joseph Jude
- Rutgers Institute for Translational Medicine and Science, Child Health Institute of New Jersey, Rutgers New Jersey School of Medicine, Rutgers, New Jersey 07103
| | - Tolga Barker
- Molecular Signal Transduction Section, NIAID, National Institutes of Health, Bethesda, Maryland 20892
| | - Cynthia A Koziol-White
- Rutgers Institute for Translational Medicine and Science, Child Health Institute of New Jersey, Rutgers New Jersey School of Medicine, Rutgers, New Jersey 07103
| | - Michelle Ma
- Inflammation Immunobiology Section, NIAID, National Institutes of Health, Bethesda, Maryland 20892
| | - Reynold A Panettieri
- Rutgers Institute for Translational Medicine and Science, Child Health Institute of New Jersey, Rutgers New Jersey School of Medicine, Rutgers, New Jersey 07103
| | - Dianqing Wu
- Department of Pharmacology, Yale University School of Medicine, New Haven, Connecticut 06510
| | - Helene F Rosenberg
- Inflammation Immunobiology Section, NIAID, National Institutes of Health, Bethesda, Maryland 20892
| | - Kirk M Druey
- Molecular Signal Transduction Section, NIAID, National Institutes of Health, Bethesda, Maryland 20892.
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25
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Suppression of RGSz1 function optimizes the actions of opioid analgesics by mechanisms that involve the Wnt/β-catenin pathway. Proc Natl Acad Sci U S A 2018; 115:E2085-E2094. [PMID: 29440403 DOI: 10.1073/pnas.1707887115] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Regulator of G protein signaling z1 (RGSz1), a member of the RGS family of proteins, is present in several networks expressing mu opioid receptors (MOPRs). By using genetic mouse models for global or brain region-targeted manipulations of RGSz1 expression, we demonstrated that the suppression of RGSz1 function increases the analgesic efficacy of MOPR agonists in male and female mice and delays the development of morphine tolerance while decreasing the sensitivity to rewarding and locomotor activating effects. Using biochemical assays and next-generation RNA sequencing, we identified a key role of RGSz1 in the periaqueductal gray (PAG) in morphine tolerance. Chronic morphine administration promotes RGSz1 activity in the PAG, which in turn modulates transcription mediated by the Wnt/β-catenin signaling pathway to promote analgesic tolerance to morphine. Conversely, the suppression of RGSz1 function stabilizes Axin2-Gαz complexes near the membrane and promotes β-catenin activation, thereby delaying the development of analgesic tolerance. These data show that the regulation of RGS complexes, particularly those involving RGSz1-Gαz, represents a promising target for optimizing the analgesic actions of opioids without increasing the risk of dependence or addiction.
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26
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Abstract
Schizophrenia is a complex disorder lacking an effective treatment option for the pervasive and debilitating cognitive impairments experienced by patients. Working memory is a core cognitive function impaired in schizophrenia that depends upon activation of distributed neural network, including the circuitry of the dorsolateral prefrontal cortex (DLPFC). Accordingly, individuals diagnosed with schizophrenia show reduced DLPFC activation while performing working-memory tasks. This lower DLPFC activation appears to be an integral part of the disease pathophysiology, and not simply a reflection of poor performance. Thus, the cellular and circuitry alterations that underlie lower DLPFC neuronal activity in schizophrenia must be determined in order to identify appropriate therapeutic targets. Studies using human postmortem brain tissue provide a robust way to investigate and characterize these cellular and circuitry alterations at multiple levels of resolution, and such studies provide essential information that cannot be obtained either through in vivo studies in humans or through experimental animal models. Studies examining neuronal morphology, protein expression and localization, and transcript levels indicate that a microcircuit composed of excitatory pyramidal cells and inhibitory interneurons containing the calcium-binding protein parvalbumin is altered in the DLPFC of subjects with schizophrenia and likely contributes to DLPFC dysfunction.
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Affiliation(s)
- Jill R Glausier
- Translational Neuroscience Program, Department of Psychiatry, University of Pittsburgh, Pittsburgh, PA, United States
| | - David A Lewis
- Translational Neuroscience Program, Department of Psychiatry, University of Pittsburgh, Pittsburgh, PA, United States.
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27
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Pallaki P, Georganta EM, Serafimidis I, Papakonstantinou MP, Papanikolaou V, Koutloglou S, Papadimitriou E, Agalou A, Tserga A, Simeonof A, Thomaidou D, Gaitanou M, Georgoussi Z. A novel regulatory role of RGS4 in STAT5B activation, neurite outgrowth and neuronal differentiation. Neuropharmacology 2017; 117:408-421. [PMID: 28219718 DOI: 10.1016/j.neuropharm.2017.02.012] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2016] [Revised: 02/01/2017] [Accepted: 02/14/2017] [Indexed: 12/26/2022]
Abstract
The Regulator of G protein Signalling 4 (RGS4) is a multitask protein that interacts with and negatively modulates opioid receptor signalling. Previously, we showed that the δ-opioid receptor (δ-OR) forms a multiprotein signalling complex consisting of Gi/Go proteins and the Signal Transducer and Activator of Transcription 5B (STAT5B) that leads to neuronal differentiation and neurite outgrowth upon δ-ΟR activation. Here, we investigated whether RGS4 could participate in signalling pathways to regulate neurotropic events. We demonstrate that RGS4 interacts directly with STAT5B independently of δ-ΟR presence both in vitro and in living cells. This interaction involves the N-terminal portion of RGS4 and the DNA-binding SH3 domain of STAT5B. Expression of RGS4 in HEK293 cells expressing δ-OR and/or erythropoietin receptor results in inhibition of [D-Ser2, Leu5, Thr6]-enkephalin (DSLET)-and erythropoietin-dependent STAT5B phosphorylation and subsequent transcriptional activation. DSLET-dependent neurite outgrowth of neuroblastoma cells is also blocked by RGS4 expression, whereas primary cortical cultures of RGS4 knockout mice (RGS4-/-) exhibit enhanced neuronal sprouting after δ-OR activation. Additional studies in adult brain extracts from RGS4-/- mice revealed increased levels of p-STAT5B. Finally, neuronal progenitor cultures from RGS4-/- mice exhibit enhanced proliferation with concomitant increases in the mRNA levels of the anti-apoptotic STAT5B target genes bcl2 and bcl-xl. These observations suggest that RGS4 is implicated in opioid dependent neuronal differentiation and neurite outgrowth via a "non-canonical" signaling pathway regulating STAT5B-directed responses.
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Affiliation(s)
- Paschalina Pallaki
- Laboratory of Cellular Signalling and Molecular Pharmacology, Institute of Biosciences and Applications, National Centre for Scientific Research «Demokritos», 15310 Athens, Greece
| | - Eirini-Maria Georganta
- Laboratory of Cellular Signalling and Molecular Pharmacology, Institute of Biosciences and Applications, National Centre for Scientific Research «Demokritos», 15310 Athens, Greece
| | - Ioannis Serafimidis
- Laboratory of Developmental Biology, Biomedical Research Foundation of the Academy of Athens, 11527 Athens, Greece
| | - Maria-Pagona Papakonstantinou
- Laboratory of Cellular Signalling and Molecular Pharmacology, Institute of Biosciences and Applications, National Centre for Scientific Research «Demokritos», 15310 Athens, Greece
| | - Vassilis Papanikolaou
- Laboratory of Cellular Signalling and Molecular Pharmacology, Institute of Biosciences and Applications, National Centre for Scientific Research «Demokritos», 15310 Athens, Greece
| | - Sofia Koutloglou
- Laboratory of Cellular Signalling and Molecular Pharmacology, Institute of Biosciences and Applications, National Centre for Scientific Research «Demokritos», 15310 Athens, Greece
| | - Elsa Papadimitriou
- Laboratory of Cellular and Molecular Neurobiology, Hellenic Pasteur Institute, 11521 Athens, Greece
| | - Adamantia Agalou
- Laboratory of Cellular Signalling and Molecular Pharmacology, Institute of Biosciences and Applications, National Centre for Scientific Research «Demokritos», 15310 Athens, Greece
| | - Aggeliki Tserga
- Laboratory of Cellular Signalling and Molecular Pharmacology, Institute of Biosciences and Applications, National Centre for Scientific Research «Demokritos», 15310 Athens, Greece
| | - Alexandra Simeonof
- Laboratory of Cellular Signalling and Molecular Pharmacology, Institute of Biosciences and Applications, National Centre for Scientific Research «Demokritos», 15310 Athens, Greece
| | - Dimitra Thomaidou
- Laboratory of Cellular and Molecular Neurobiology, Hellenic Pasteur Institute, 11521 Athens, Greece
| | - Maria Gaitanou
- Laboratory of Cellular and Molecular Neurobiology, Hellenic Pasteur Institute, 11521 Athens, Greece
| | - Zafiroula Georgoussi
- Laboratory of Cellular Signalling and Molecular Pharmacology, Institute of Biosciences and Applications, National Centre for Scientific Research «Demokritos», 15310 Athens, Greece.
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28
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Druey KM. Emerging Roles of Regulators of G Protein Signaling (RGS) Proteins in the Immune System. Adv Immunol 2017; 136:315-351. [PMID: 28950950 DOI: 10.1016/bs.ai.2017.05.001] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Affiliation(s)
- Kirk M Druey
- Molecular Signal Transduction Section, Laboratory of Allergic Diseases, NIAID/NIH, Bethesda, MD, United States.
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29
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Ahlers KE, Chakravarti B, Fisher RA. RGS6 as a Novel Therapeutic Target in CNS Diseases and Cancer. AAPS JOURNAL 2016; 18:560-72. [PMID: 27002730 DOI: 10.1208/s12248-016-9899-9] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/13/2015] [Accepted: 02/25/2016] [Indexed: 12/17/2022]
Abstract
Regulator of G protein signaling (RGS) proteins are gatekeepers regulating the cellular responses induced by G protein-coupled receptor (GPCR)-mediated activation of heterotrimeric G proteins. Specifically, RGS proteins determine the magnitude and duration of GPCR signaling by acting as a GTPase-activating protein for Gα subunits, an activity facilitated by their semiconserved RGS domain. The R7 subfamily of RGS proteins is distinguished by two unique domains, DEP/DHEX and GGL, which mediate membrane targeting and stability of these proteins. RGS6, a member of the R7 subfamily, has been shown to specifically modulate Gαi/o protein activity which is critically important in the central nervous system (CNS) for neuronal responses to a wide array of neurotransmitters. As such, RGS6 has been implicated in several CNS pathologies associated with altered neurotransmission, including the following: alcoholism, anxiety/depression, and Parkinson's disease. In addition, unlike other members of the R7 subfamily, RGS6 has been shown to regulate G protein-independent signaling mechanisms which appear to promote both apoptotic and growth-suppressive pathways that are important in its tumor suppressor function in breast and possibly other tissues. Further highlighting the importance of RGS6 as a target in cancer, RGS6 mediates the chemotherapeutic actions of doxorubicin and blocks reticular activating system (Ras)-induced cellular transformation by promoting degradation of DNA (cytosine-5)-methyltransferase 1 (DNMT1) to prevent its silencing of pro-apoptotic and tumor suppressor genes. Together, these findings demonstrate the critical role of RGS6 in regulating both G protein-dependent CNS pathology and G protein-independent cancer pathology implicating RGS6 as a novel therapeutic target.
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Affiliation(s)
- Katelin E Ahlers
- Department of Pharmacology, The Roy J. and Lucille A. Carver College of Medicine, University of Iowa, 2-505 Bowen Science Building, Iowa City, Iowa, 52242, USA
| | - Bandana Chakravarti
- Department of Pharmacology, The Roy J. and Lucille A. Carver College of Medicine, University of Iowa, 2-505 Bowen Science Building, Iowa City, Iowa, 52242, USA
| | - Rory A Fisher
- Department of Pharmacology, The Roy J. and Lucille A. Carver College of Medicine, University of Iowa, 2-505 Bowen Science Building, Iowa City, Iowa, 52242, USA. .,Department of Internal Medicine, The Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, Iowa, 52242, USA.
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30
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Kimoto S, Glausier JR, Fish KN, Volk DW, Bazmi HH, Arion D, Datta D, Lewis DA. Reciprocal Alterations in Regulator of G Protein Signaling 4 and microRNA16 in Schizophrenia. Schizophr Bull 2016; 42:396-405. [PMID: 26424323 PMCID: PMC4753606 DOI: 10.1093/schbul/sbv139] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
N-methyl-d-aspartate receptor (NMDAR) hypofunction in the dorsolateral prefrontal cortex (DLPFC) has been implicated in the pathology of schizophrenia. NMDAR activity is negatively regulated by some G protein-coupled receptors (GPCRs). Signaling through these GPCRs is reduced by Regulator of G protein Signaling 4 (RGS4). Thus, lower levels of RGS4 would enhance GPCR-mediated reductions in NMDAR activity and could contribute to NMDAR hypofunction in schizophrenia. In this study, we quantified RGS4 mRNA and protein levels at several levels of resolution in the DLPFC from subjects with schizophrenia and matched healthy comparison subjects. To investigate molecular mechanisms that could contribute to altered RGS4 levels, we quantified levels of small noncoding RNAs, known as microRNAs (miRs), which regulate RGS4 mRNA integrity after transcription. RGS4 mRNA and protein levels were significantly lower in schizophrenia subjects and were positively correlated across all subjects. The RGS4 mRNA deficit was present in pyramidal neurons of DLPFC layers 3 and 5 of the schizophrenia subjects. In contrast, levels of miR16 were significantly higher in the DLPFC of schizophrenia subjects, and higher miR16 levels predicted lower RGS4 mRNA levels. These findings provide convergent evidence of lower RGS4 mRNA and protein levels in schizophrenia that may result from increased expression of miR16. Given the role of RGS4 in regulating GPCRs, and consequently the strength of NMDAR signaling, these findings could contribute to the molecular substrate for NMDAR hypofunction in DLPFC pyramidal cells in schizophrenia.
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Affiliation(s)
- Sohei Kimoto
- Department of Psychiatry, University of Pittsburgh, Pittsburgh, PA; Department of Psychiatry, Nara Medical University, Nara, Japan
| | - Jill R Glausier
- Department of Psychiatry, University of Pittsburgh, Pittsburgh, PA
| | - Kenneth N Fish
- Department of Psychiatry, University of Pittsburgh, Pittsburgh, PA
| | - David W Volk
- Department of Psychiatry, University of Pittsburgh, Pittsburgh, PA
| | - H Holly Bazmi
- Department of Psychiatry, University of Pittsburgh, Pittsburgh, PA
| | - Dominique Arion
- Department of Psychiatry, University of Pittsburgh, Pittsburgh, PA
| | - Dibyadeep Datta
- Department of Psychiatry, University of Pittsburgh, Pittsburgh, PA
| | - David A Lewis
- Department of Psychiatry, University of Pittsburgh, Pittsburgh, PA; Department of Neuroscience, University of Pittsburgh, Pittsburgh, PA
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31
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Tinker A, Finlay M, Nobles M, Opel A. The contribution of pathways initiated via the Gq\11 G-protein family to atrial fibrillation. Pharmacol Res 2016; 105:54-61. [DOI: 10.1016/j.phrs.2015.11.008] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/18/2015] [Accepted: 11/19/2015] [Indexed: 01/28/2023]
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32
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Kamp ME, Liu Y, Kortholt A. Function and Regulation of Heterotrimeric G Proteins during Chemotaxis. Int J Mol Sci 2016; 17:ijms17010090. [PMID: 26784171 PMCID: PMC4730333 DOI: 10.3390/ijms17010090] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2015] [Revised: 12/22/2015] [Accepted: 12/31/2015] [Indexed: 01/10/2023] Open
Abstract
Chemotaxis, or directional movement towards an extracellular gradient of chemicals, is necessary for processes as diverse as finding nutrients, the immune response, metastasis and wound healing. Activation of G-protein coupled receptors (GPCRs) is at the very base of the chemotactic signaling pathway. Chemotaxis starts with binding of the chemoattractant to GPCRs at the cell-surface, which finally leads to major changes in the cytoskeleton and directional cell movement towards the chemoattractant. Many chemotaxis pathways that are directly regulated by Gβγ have been identified and studied extensively; however, whether Gα is just a handle that regulates the release of Gβγ or whether Gα has its own set of distinct chemotactic effectors, is only beginning to be understood. In this review, we will discuss the different levels of regulation in GPCR signaling and the downstream pathways that are essential for proper chemotaxis.
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Affiliation(s)
- Marjon E Kamp
- Department of Cell Biochemistry, University of Groningen, Nijenborgh 7, 9747 AG Groningen, The Netherlands.
| | - Youtao Liu
- Department of Cell Biochemistry, University of Groningen, Nijenborgh 7, 9747 AG Groningen, The Netherlands.
| | - Arjan Kortholt
- Department of Cell Biochemistry, University of Groningen, Nijenborgh 7, 9747 AG Groningen, The Netherlands.
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Gerber KJ, Squires KE, Hepler JR. Roles for Regulator of G Protein Signaling Proteins in Synaptic Signaling and Plasticity. Mol Pharmacol 2015; 89:273-86. [PMID: 26655302 DOI: 10.1124/mol.115.102210] [Citation(s) in RCA: 79] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2015] [Accepted: 12/10/2015] [Indexed: 11/22/2022] Open
Abstract
The regulator of G protein signaling (RGS) family of proteins serves critical roles in G protein-coupled receptor (GPCR) and heterotrimeric G protein signal transduction. RGS proteins are best understood as negative regulators of GPCR/G protein signaling. They achieve this by acting as GTPase activating proteins (GAPs) for Gα subunits and accelerating the turnoff of G protein signaling. Many RGS proteins also bind additional signaling partners that either regulate their functions or enable them to regulate other important signaling events. At neuronal synapses, GPCRs, G proteins, and RGS proteins work in coordination to regulate key aspects of neurotransmitter release, synaptic transmission, and synaptic plasticity, which are necessary for central nervous system physiology and behavior. Accumulating evidence has revealed key roles for specific RGS proteins in multiple signaling pathways at neuronal synapses, regulating both pre- and postsynaptic signaling events and synaptic plasticity. Here, we review and highlight the current knowledge of specific RGS proteins (RGS2, RGS4, RGS7, RGS9-2, and RGS14) that have been clearly demonstrated to serve critical roles in modulating synaptic signaling and plasticity throughout the brain, and we consider their potential as future therapeutic targets.
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Affiliation(s)
- Kyle J Gerber
- Programs in Molecular and Systems Pharmacology (K.J.G., K.E.S., J.R.H.) and Neuroscience (J.R.H.), Department of Pharmacology (K.J.G., K.E.S., J.R.H.), Emory University School of Medicine, Atlanta, Georgia
| | - Katherine E Squires
- Programs in Molecular and Systems Pharmacology (K.J.G., K.E.S., J.R.H.) and Neuroscience (J.R.H.), Department of Pharmacology (K.J.G., K.E.S., J.R.H.), Emory University School of Medicine, Atlanta, Georgia
| | - John R Hepler
- Programs in Molecular and Systems Pharmacology (K.J.G., K.E.S., J.R.H.) and Neuroscience (J.R.H.), Department of Pharmacology (K.J.G., K.E.S., J.R.H.), Emory University School of Medicine, Atlanta, Georgia
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Luo Y, Qin SL, Yu MH, Mu YF, Wang ZS, Zhong M. Prognostic value of regulator of G-protein signaling 6 in colorectal cancer. Biomed Pharmacother 2015; 76:147-52. [DOI: 10.1016/j.biopha.2015.10.012] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2015] [Accepted: 10/14/2015] [Indexed: 10/22/2022] Open
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Opel A, Nobles M, Montaigne D, Finlay M, Anderson N, Breckenridge R, Tinker A. Absence of the Regulator of G-protein Signaling, RGS4, Predisposes to Atrial Fibrillation and Is Associated with Abnormal Calcium Handling. J Biol Chem 2015; 290:19233-44. [PMID: 26088132 PMCID: PMC4521044 DOI: 10.1074/jbc.m115.666719] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2015] [Revised: 06/15/2015] [Indexed: 01/11/2023] Open
Abstract
The description of potential molecular substrates for predisposition to atrial fibrillation (AF) is incomplete, and it is unknown what role regulators of G-protein signaling might play. We address whether the attenuation of RGS4 function may promote AF and the mechanism through which this occurs. For this purpose, we studied a mouse with global genetic deletion of RGS4 (RGS4(-/-)) and the normal littermate controls (RGS4(+/+)). In vivo electrophysiology using atrial burst pacing revealed that mice with global RGS4 deletion developed AF more frequently than control littermates. Isolated atrial cells from RGS4(-/-) mice show an increase in Ca(2+) spark frequency under basal conditions and after the addition of endothelin-1 and abnormal spontaneous Ca(2+) release events after field stimulation. Isolated left atria studied on a multielectrode array revealed modest changes in path length for re-entry but abnormal electrical events after a pacing train in RGS4(-/-) mice. RGS4 deletion results in a predisposition to atrial fibrillation from enhanced activity in the Gαq/11-IP3 pathway, resulting in abnormal Ca(2+) release and corresponding electrical events.
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Affiliation(s)
- Aaisha Opel
- From the British Heart Foundation Laboratories, Department of Medicine, University College London, Rayne Institute, London WC1E 6JJ, United Kingdom and the William Harvey Heart Centre, Barts & The London School of Medicine & Dentistry, London EC1M 6BQ, United Kingdom
| | - Muriel Nobles
- the William Harvey Heart Centre, Barts & The London School of Medicine & Dentistry, London EC1M 6BQ, United Kingdom
| | - David Montaigne
- the William Harvey Heart Centre, Barts & The London School of Medicine & Dentistry, London EC1M 6BQ, United Kingdom
| | - Malcolm Finlay
- the William Harvey Heart Centre, Barts & The London School of Medicine & Dentistry, London EC1M 6BQ, United Kingdom
| | - Naomi Anderson
- the William Harvey Heart Centre, Barts & The London School of Medicine & Dentistry, London EC1M 6BQ, United Kingdom
| | - Ross Breckenridge
- From the British Heart Foundation Laboratories, Department of Medicine, University College London, Rayne Institute, London WC1E 6JJ, United Kingdom and
| | - Andrew Tinker
- From the British Heart Foundation Laboratories, Department of Medicine, University College London, Rayne Institute, London WC1E 6JJ, United Kingdom and the William Harvey Heart Centre, Barts & The London School of Medicine & Dentistry, London EC1M 6BQ, United Kingdom
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Santhappan R, Crowder AT, Gouty S, Cox BM, Côté TE. Mu opioid receptor activation enhances regulator of G protein signaling 4 association with the mu opioid receptor/G protein complex in a GTP-dependent manner. J Neurochem 2015; 135:76-87. [PMID: 26119705 PMCID: PMC5034817 DOI: 10.1111/jnc.13222] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2015] [Revised: 06/19/2015] [Accepted: 06/25/2015] [Indexed: 11/26/2022]
Abstract
The interaction of Regulator of G protein Signaling 4 (RGS4) with the rat mu opioid receptor (MOR)/G protein complex was investigated. Solubilized MOR from rat brain membranes was immunoprecipitated in the presence of RGS4 with antibodies against the N-terminus of MOR (anti-MOR10-70 ). Activation of MOR with [D-Ala(2) , N-Me-Phe(4) , Gly(5) -ol] enkephalin (DAMGO) during immunoprecipitation caused a 150% increase in Goα and a 50% increase in RGS4 in the pellet. When 10 μM GTP was included with DAMGO, there was an additional 72% increase in RGS4 co-immunoprecipitating with MOR (p = 0.003). Guanosine 5'-O-(3-thiotriphosphate) (GTPγS) increased the amount of co-precipitating RGS4 by 93% (compared to DAMGO alone, p = 0.008), and the inclusion of GTPγS caused the ratio of MOR to RGS4 to be 1 : 1 (31 fmoles : 28 fmoles, respectively). GTPγS also increased the association of endogenous RGS4 with MOR. In His6 RGS4/Ni(2+) -NTA agarose pull down experiments, 0.3 μM GTPγS tripled the binding of Goα to His6 RGS4, whereas the addition of 100 μM GDP blocked this effect. Importantly, activation of solubilized MOR with DAMGO in the presence of 100 μM GDP and 0.3 μM GTPγS increased Goα binding to His6 RGS4/Ni(2+) -NTA agarose (p = 0.001). Regulators of G protein Signaling (RGS) shorten the time that G proteins are active. Activation of the mu opioid receptor (MOR) causes GTP to bind to and to activate Go (αoβγ). RGS4 then binds to the activated αo-GTP/MOR complex and accelerates the intrinsic GTPase of αo. After αo dissociates from MOR, RGS4 remains bound to the C-terminal region of MOR.
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Affiliation(s)
- Rema Santhappan
- Department of Pharmacology, The Uniformed Services University of the Health Sciences, Bethesda, Maryland, USA
| | - Alicia Tamara Crowder
- Department of Pharmacology, The Uniformed Services University of the Health Sciences, Bethesda, Maryland, USA.,Neuroscience Program, The Uniformed Services University of the Health Sciences, Bethesda, Maryland, USA
| | - Shawn Gouty
- Department of Pharmacology, The Uniformed Services University of the Health Sciences, Bethesda, Maryland, USA
| | - Brian M Cox
- Department of Pharmacology, The Uniformed Services University of the Health Sciences, Bethesda, Maryland, USA.,Neuroscience Program, The Uniformed Services University of the Health Sciences, Bethesda, Maryland, USA
| | - Thomas E Côté
- Department of Pharmacology, The Uniformed Services University of the Health Sciences, Bethesda, Maryland, USA.,Neuroscience Program, The Uniformed Services University of the Health Sciences, Bethesda, Maryland, USA
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Doupnik CA. RGS Redundancy and Implications in GPCR-GIRK Signaling. INTERNATIONAL REVIEW OF NEUROBIOLOGY 2015; 123:87-116. [PMID: 26422983 DOI: 10.1016/bs.irn.2015.05.010] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
Abstract
Regulators of G protein signaling (RGS proteins) are key components of GPCR complexes, interacting directly with G protein α-subunits to enhance their intrinsic GTPase activity. The functional consequence is an accelerated termination of G protein effectors including certain ion channels. RGS proteins have a profound impact on the membrane-delimited gating behavior of G-protein-activated inwardly rectifying K(+) (GIRK) channels as demonstrated in reconstitution assays and recent RGS knockout mice studies. Akin to GPCRs and G protein αβγ subunits, multiple RGS isoforms are expressed within single GIRK-expressing neurons, suggesting functional redundancy and/or specificity in GPCR-GIRK channel signaling. The extent and impact of RGS redundancy in neuronal GPCR-GIRK channel signaling is currently not fully appreciated; however, recent studies from RGS knockout mice are providing important new clues on the impact of individual endogenous RGS proteins and the extent of RGS functional redundancy. Incorporating "tools" such as engineered RGS-resistant Gαi/o subunits provide an important assessment method for determining the impact of all endogenous RGS proteins on a given GPCR response and an accounting benchmark to assess the impact of individual RGS knockouts on overall RGS redundancy within a given neuron. Elucidating the degree of regulation attributable to specific RGS proteins in GIRK channel function will aid in the assessment of individual RGS proteins as viable therapeutic targets in epilepsy, ataxia's, memory disorders, and a growing list of neurological disorders.
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Affiliation(s)
- Craig A Doupnik
- Department of Molecular Pharmacology & Physiology, University of South Florida College of Medicine, Tampa, Florida, USA.
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Arnold C, Feldner A, Pfisterer L, Hödebeck M, Troidl K, Genové G, Wieland T, Hecker M, Korff T. RGS5 promotes arterial growth during arteriogenesis. EMBO Mol Med 2015; 6:1075-89. [PMID: 24972930 PMCID: PMC4154134 DOI: 10.15252/emmm.201403864] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Arteriogenesis—the growth of collateral arterioles—partially compensates for the progressive occlusion of large conductance arteries as it may occur as a consequence of coronary, cerebral or peripheral artery disease. Despite being clinically highly relevant, mechanisms driving this process remain elusive. In this context, our study revealed that abundance of regulator of G-protein signalling 5 (RGS5) is increased in vascular smooth muscle cells (SMCs) of remodelling collateral arterioles. RGS5 terminates G-protein-coupled signalling cascades which control contractile responses of SMCs. Consequently, overexpression of RGS5 blunted Gαq/11-mediated mobilization of intracellular calcium, thereby facilitating Gα12/13-mediated RhoA signalling which is crucial for arteriogenesis. Knockdown of RGS5 evoked opposite effects and thus strongly impaired collateral growth as evidenced by a blockade of RhoA activation, SMC proliferation and the inability of these cells to acquire an activated phenotype in RGS5-deficient mice after the onset of arteriogenesis. Collectively, these findings establish RGS5 as a novel determinant of arteriogenesis which shifts G-protein signalling from Gαq/11-mediated calcium-dependent contraction towards Gα12/13-mediated Rho kinase-dependent SMC activation. Subject Categories Vascular Biology & Angiogenesis
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Affiliation(s)
- Caroline Arnold
- Division of Cardiovascular Physiology, Institute of Physiology and Pathophysiology, University of Heidelberg, Heidelberg, Germany
| | - Anja Feldner
- Division of Cardiovascular Physiology, Institute of Physiology and Pathophysiology, University of Heidelberg, Heidelberg, Germany
| | - Larissa Pfisterer
- Division of Cardiovascular Physiology, Institute of Physiology and Pathophysiology, University of Heidelberg, Heidelberg, Germany
| | - Maren Hödebeck
- Division of Cardiovascular Physiology, Institute of Physiology and Pathophysiology, University of Heidelberg, Heidelberg, Germany
| | - Kerstin Troidl
- Department of Pharmacology, Max-Planck-Institute for Heart and Lung Research, Bad Nauheim, Germany
| | - Guillem Genové
- Division of Vascular Biology, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden
| | - Thomas Wieland
- Institute of Experimental and Clinical Pharmacology and Toxicology, University of Heidelberg, Mannheim, Germany
| | - Markus Hecker
- Division of Cardiovascular Physiology, Institute of Physiology and Pathophysiology, University of Heidelberg, Heidelberg, Germany
| | - Thomas Korff
- Division of Cardiovascular Physiology, Institute of Physiology and Pathophysiology, University of Heidelberg, Heidelberg, Germany
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Regulator of G protein signaling 6 is a critical mediator of both reward-related behavioral and pathological responses to alcohol. Proc Natl Acad Sci U S A 2015; 112:E786-95. [PMID: 25646431 DOI: 10.1073/pnas.1418795112] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Alcohol is the most commonly abused drug worldwide, and chronic alcohol consumption is a major etiological factor in the development of multiple pathological sequelae, including alcoholic cardiomyopathy and hepatic cirrhosis. Here, we identify regulator of G protein signaling 6 (RGS6) as a critical regulator of both alcohol-seeking behaviors and the associated cardiac and hepatic morbidities through two mechanistically divergent signaling actions. RGS6(-/-) mice consume less alcohol when given free access and are less susceptible to alcohol-induced reward and withdrawal. Antagonism of GABA(B) receptors or dopamine D2 receptors partially reversed the reduction in alcohol consumption in RGS6(-/-) animals. Strikingly, dopamine transporter inhibition completely restored alcohol seeking in mice lacking RGS6. RGS6 deficiency was associated with alterations in the expression of genes controlling dopamine (DA) homeostasis and a reduction in DA levels in the striatum. Taken together, these data implicate RGS6 as an essential regulator of DA bioavailability. RGS6 deficiency also provided dramatic protection against cardiac hypertrophy and fibrosis, hepatic steatosis, and gastrointestinal barrier dysfunction and endotoxemia when mice were forced to consume alcohol. Although RGS proteins canonically function as G-protein regulators, RGS6-dependent, alcohol-mediated toxicity in the heart, liver, and gastrointestinal tract involves the ability of RGS6 to promote reactive oxygen species-dependent apoptosis, an action independent of its G-protein regulatory capacity. We propose that inhibition of RGS6 might represent a viable means to reduce alcohol cravings and withdrawal in human patients, while simultaneously protecting the heart and liver from further damage upon relapse.
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Noncanonical G-protein-dependent modulation of osteoclast differentiation and bone resorption mediated by Pasteurella multocida toxin. mBio 2014; 5:e02190. [PMID: 25389180 PMCID: PMC4235216 DOI: 10.1128/mbio.02190-14] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Pasteurella multocida toxin (PMT) induces atrophic rhinitis in animals, which is characterized by a degradation of nasal turbinate bones, indicating an effect of the toxin on bone cells such as osteoblasts and osteoclasts. The underlying molecular mechanism of PMT was defined as a persistent activation of heterotrimeric G proteins by deamidation of a specific glutamine residue. Here, we show that PMT acts directly on osteoclast precursor cells such as bone marrow-derived CD14+ monocytes and RAW246.7 cells to induce osteoclastogenesis as measured by expression of osteoclast-specific markers such as tartrate-resistant acid phosphatase and bone resorption activity. Treatment performed solely with PMT stimulates osteoclast differentiation, showing a receptor activator of nuclear factor-κB ligand (RANKL)-independent action of the toxin. The underlying signal transduction pathway was defined as activation of the heterotrimeric G proteins Gαq/11 leading to the transactivation of Ras and the mitogen-activated protein kinase pathway. Gαq/11 transactivates Ras via its effector phospholipase Cβ-protein kinase C (PKC) involving proline-rich tyrosine kinase 2 (Pyk2). PMT-induced activation of the mitogen-activated protein kinase pathway results in stimulation of the osteoclastogenic transcription factors AP-1, NF-κB, and NFATc1. In addition, Ca2+-dependent calcineurin activation of NFAT is crucial for PMT-induced osteoclastogenesis. The data not only elucidate a rationale for PMT-dependent bone loss during atrophic rhinitis but also highlight a noncanonical, G-protein-dependent pathway toward bone resorption that is distinct from the RANKL-RANK pathway but mimics it. We define heterotrimeric G proteins as as-yet-underestimated entities/players in the maturation of osteoclasts which might be of pharmacological relevance. Pasteurella multocida toxin (PMT) induces degradation of nasal turbinate bones, leading to the syndrome of atrophic rhinitis. Recently, the molecular mechanism and substrate specificity of PMT were identified. The toxin activates heterotrimeric G proteins by a covalent modification. However, the mechanism by which PMT induces bone degradation is poorly understood. Our report demonstrates a direct effect of PMT on osteoclast precursor cells, leading to maturation of bone-degrading osteoclasts. Interestingly, PMT stimulates osteoclastogenesis independently of the cytokine RANKL, which is a key factor in induction of osteoclast differentiation. This implicates a noncanonical osteoclastogenic signaling pathway induced by PMT. The elucidated Gαq/11-dependent osteoclastogenic signal transduction pathway ends in osteoclastogenic NFAT signaling. The noncanonical, heterotrimeric G protein-dependent osteoclast differentiation process may be of pharmacological relevance, as members of this pathway are highly druggable. In particular, modulation of G protein-coupled receptor activity in osteoclast progenitors by small molecules might be of specific interest.
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Obsilova V, Kopecka M, Kosek D, Kacirova M, Kylarova S, Rezabkova L, Obsil T. Mechanisms of the 14-3-3 protein function: regulation of protein function through conformational modulation. Physiol Res 2014; 63:S155-64. [PMID: 24564655 DOI: 10.33549/physiolres.932659] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Many aspects of protein function regulation require specific protein-protein interactions to carry out the exact biochemical and cellular functions. The highly conserved members of the 14-3-3 protein family mediate such interactions and through binding to hundreds of other proteins provide multitude of regulatory functions, thus playing key roles in many cellular processes. The 14-3-3 protein binding can affect the function of the target protein in many ways including the modulation of its enzyme activity, its subcellular localization, its structure and stability, or its molecular interactions. In this minireview, we focus on mechanisms of the 14-3-3 protein-dependent regulation of three important 14-3-3 binding partners: yeast neutral trehalase Nth1, regulator of G-protein signaling 3 (RGS3), and phosducin.
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Affiliation(s)
- V Obsilova
- Department of Protein Structure, Institute of Physiology Academy of Sciences of the Czech Republic, Prague, Czech Republic. and
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Jiang N, Xue R, Bu F, Tong X, Qiang J, Liu R. Decreased RGS6 expression is associated with poor prognosis in pancreatic cancer patients. INTERNATIONAL JOURNAL OF CLINICAL AND EXPERIMENTAL PATHOLOGY 2014; 7:4120-4127. [PMID: 25120791 PMCID: PMC4129026] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Received: 05/08/2014] [Accepted: 06/25/2014] [Indexed: 06/03/2023]
Abstract
Regulator of G-protein signaling 6 (RGS6), a member of a family of RGS proteins, has been reported to involve in multiple processes during tumor development. However, its role in pancreatic cancer has not been studied yet. In this study, we aimed to investigate the expression of RGS6 in pancreatic cancer and its role in predicting outcomes of patients with pancreatic cancer. We first measured the expression of RGS6 mRNA in 20 cases of tumor tissues and matched adjacent non-tumorous tissues by quantitative real-time PCR and examined RGS6 protein by immunohistochemistry in tissue microarrays containing 90 tumor and 90 paired adjacent non-tumor tissues. Decreased RGS6 mRNA detected in primary tumor, compared with their non-tumor counterparts. In addition, decreased RGS6 protein expression was associated with tumor differentiation (P = 0.027), pT classification (P = 0.034), smoking status (P = 0.041) and a poor survival (P = 0.007). Cox proportional hazards regression modeling analysis revealed that lymph node metastasis (P = 0.001; hazard ratio, 2.347, 95% CI, 1.387-3.972), tumor differentiation (P = 0.015; hazard ratio, 0.505, 95% CI, 0.291-0.876) and RGS6 expression (P = 0.048; hazard ratio, 0.567, 95% CI, 0.324-0.994) were three independent prognostic factors. Taken together, these date demonstrate that RGS6 decreases in tumor tissue and may serve as a novel biomarker for outcomes in pancreatic cancer patients and be a potential therapeutic target potential therapeutic target.
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Affiliation(s)
- Nan Jiang
- Department of Surgical Oncology, Chinese People’s Liberation Army (PLA) General Hospital28 Fuxing Road, Beijing 100853, China
| | - Ruihua Xue
- Department of Surgical Oncology, Chinese People’s Liberation Army (PLA) General Hospital28 Fuxing Road, Beijing 100853, China
| | - Fangfang Bu
- Department of Cancer Center, Chinese People’s Liberation Army (PLA) General Hospital28 Fuxing Road, Beijing 100853, China
| | - Xin Tong
- Department of Cancer Center, Chinese People’s Liberation Army (PLA) General Hospital28 Fuxing Road, Beijing 100853, China
| | - Jiankun Qiang
- Department of Cancer Center, Chinese People’s Liberation Army (PLA) General Hospital28 Fuxing Road, Beijing 100853, China
| | - Rong Liu
- Department of Surgical Oncology, Chinese People’s Liberation Army (PLA) General Hospital28 Fuxing Road, Beijing 100853, China
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O'Neill PR, Gautam N. Subcellular optogenetic inhibition of G proteins generates signaling gradients and cell migration. Mol Biol Cell 2014; 25:2305-14. [PMID: 24920824 PMCID: PMC4116304 DOI: 10.1091/mbc.e14-04-0870] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Cells sense gradients of extracellular cues and generate polarized responses such as cell migration and neurite initiation. There is static information on the intracellular signaling molecules involved in these responses, but how they dynamically orchestrate polarized cell behaviors is not well understood. A limitation has been the lack of methods to exert spatial and temporal control over specific signaling molecules inside a living cell. Here we introduce optogenetic tools that act downstream of native G protein-coupled receptor (GPCRs) and provide direct control over the activity of endogenous heterotrimeric G protein subunits. Light-triggered recruitment of a truncated regulator of G protein signaling (RGS) protein or a Gβγ-sequestering domain to a selected region on the plasma membrane results in localized inhibition of G protein signaling. In immune cells exposed to spatially uniform chemoattractants, these optogenetic tools allow us to create reversible gradients of signaling activity. Migratory responses generated by this approach show that a gradient of active G protein αi and βγ subunits is sufficient to generate directed cell migration. They also provide the most direct evidence so for a global inhibition pathway triggered by Gi signaling in directional sensing and adaptation. These optogenetic tools can be applied to interrogate the mechanistic basis of other GPCR-modulated cellular functions.
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Affiliation(s)
- Patrick R O'Neill
- Department of Anesthesiology, Washington University School of Medicine, St. Louis, MO 63110
| | - N Gautam
- Department of Anesthesiology, Washington University School of Medicine, St. Louis, MO 63110Department of Genetics, Washington University School of Medicine, St. Louis, MO 63110
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Dynamics of Gαq-protein-p63RhoGEF interaction and its regulation by RGS2. Biochem J 2014; 458:131-40. [PMID: 24299002 DOI: 10.1042/bj20130782] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Some G-protein-coupled receptors regulate biological processes via Gα12/13- or Gαq/11-mediated stimulation of RhoGEFs (guanine-nucleotide-exchange factors). p63RhoGEF is known to be specifically activated by Gαq/11 and mediates a major part of the acute response of vascular smooth muscle cells to angiotensin II treatment. In order to gain information about the dynamics of receptor-mediated activation of p63RhoGEF, we developed a FRET-based assay to study interactions between Gαq-CFP and Venus-p63RhoGEF in single living cells. Upon activation of histaminergic H1 or muscarinic M3 receptors, a robust FRET signal occurred that allowed for the first time the analysis of the kinetics of this interaction in detail. On- and off-set kinetics of Gαq-p63RhoGEF interactions closely resembled the kinetics of Gαq activity. Analysis of the effect of RGS2 (regulator of G-protein signalling 2) on the dynamics of Gαq activity and their interaction with p63RhoGEF showed that RGS2 is able to accelerate both deactivation of Gαq proteins and dissociation of Gαq and p63RhoGEF to a similar extent. Furthermore, we were able to detect activation-dependent FRET between RGS2 and p63RhoGEF and observed a reduced p63RhoGEF-mediated downstream signalling in the presence of RGS2. In summary, these observations support the concept of a functional activation-dependent p63RhoGEF-Gαq-RGS2 complex.
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Chidiac P, Sobiesiak AJ, Lee KN, Gros R, Nguyen CH. The eIF2B-interacting domain of RGS2 protects against GPCR agonist-induced hypertrophy in neonatal rat cardiomyocytes. Cell Signal 2014; 26:1226-34. [PMID: 24576550 DOI: 10.1016/j.cellsig.2014.02.006] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2013] [Revised: 02/05/2014] [Accepted: 02/11/2014] [Indexed: 11/29/2022]
Abstract
The protective effect of Regulator of G protein Signaling 2 (RGS2) in cardiac hypertrophy is thought to occur through its ability to inhibit the chronic GPCR signaling that promotes pathogenic growth both in vivo and in cultured cardiomyocytes. However, RGS2 is known to have additional functions beyond its activity as a GTPase accelerating protein, such as the ability to bind to eukaryotic initiation factor, eIF2B, and inhibit protein synthesis. The RGS2 eIF2B-interacting domain (RGS2(eb)) was examined for its ability to regulate hypertrophy in neonatal ventricular myocytes. Both full-length RGS2 and RGS2(eb) were able to inhibit agonist-induced cardiomyocyte hypertrophy, but RGS2(eb) had no effect on receptor-mediated inositol phosphate production, cAMP production, or ERK 1/2 activation. These results suggest that the protective effects of RGS2 in cardiac hypertrophy may derive at least in part from its ability to govern protein synthesis.
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Affiliation(s)
- Peter Chidiac
- Department of Physiology and Pharmacology, Schulich School of Medicine and Dentistry, University of Western Ontario, London, ON N6A 5C1, Canada
| | - Alina J Sobiesiak
- Department of Physiology and Pharmacology, Schulich School of Medicine and Dentistry, University of Western Ontario, London, ON N6A 5C1, Canada
| | - Katherine N Lee
- Department of Physiology and Pharmacology, Schulich School of Medicine and Dentistry, University of Western Ontario, London, ON N6A 5C1, Canada
| | - Robert Gros
- Department of Physiology and Pharmacology, Schulich School of Medicine and Dentistry, University of Western Ontario, London, ON N6A 5C1, Canada
| | - Chau H Nguyen
- Department of Physiology and Pharmacology, Schulich School of Medicine and Dentistry, University of Western Ontario, London, ON N6A 5C1, Canada; School of Pharmacy, D'Youville College, Buffalo, NY 14201, USA.
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46
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A new non-canonical pathway of Gα(q) protein regulating mitochondrial dynamics and bioenergetics. Cell Signal 2014; 26:1135-46. [PMID: 24444709 DOI: 10.1016/j.cellsig.2014.01.009] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2013] [Accepted: 01/09/2014] [Indexed: 12/12/2022]
Abstract
Contrary to previous assumptions, G proteins do not permanently reside on the plasma membrane, but are constantly monitoring the cytoplasmic surfaces of the plasma membrane and endomembranes. Here, we report that the Gαq and Gα11 proteins locate at the mitochondria and play a role in a complex signaling pathway that regulates mitochondrial dynamics. Our results provide evidence for the presence of the heteromeric G protein (Gαq/11βγ) at the outer mitochondrial membrane and for Gαq at the inner membrane. Both localizations are necessary to maintain the proper equilibrium between fusion and fission; which is achieved by altering the activity of mitofusin proteins, Drp1, OPA1 and the membrane potential at both the outer and inner mitochondrial membranes. As a result of the absence of Gαq/11, there is a decrease in mitochondrial fusion rates and a decrease in overall respiratory capacity, ATP production and OXPHOS-dependent growth. These findings demonstrate that the presence of Gαq proteins at the mitochondria serves as a physiological function: stabilizing elongated mitochondria and regulating energy production in Drp1 and Opa1 dependent mechanisms. This thereby links organelle dynamics and physiology.
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Wydeven N, Posokhova E, Xia Z, Martemyanov KA, Wickman K. RGS6, but not RGS4, is the dominant regulator of G protein signaling (RGS) modulator of the parasympathetic regulation of mouse heart rate. J Biol Chem 2013; 289:2440-9. [PMID: 24318880 DOI: 10.1074/jbc.m113.520742] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Parasympathetic activity decreases heart rate (HR) by inhibiting pacemaker cells in the sinoatrial node (SAN). Dysregulation of parasympathetic influence has been linked to sinus node dysfunction and arrhythmia. RGS (regulator of G protein signaling) proteins are negative modulators of the parasympathetic regulation of HR and the prototypical M2 muscarinic receptor (M2R)-dependent signaling pathway in the SAN that involves the muscarinic-gated atrial K(+) channel IKACh. Both RGS4 and RGS6-Gβ5 have been implicated in these processes. Here, we used Rgs4(-/-), Rgs6(-/-), and Rgs4(-/-):Rgs6(-/-) mice to compare the relative influence of RGS4 and RGS6 on parasympathetic regulation of HR and M2R-IKACh-dependent signaling in the SAN. In retrogradely perfused hearts, ablation of RGS6, but not RGS4, correlated with decreased resting HR, increased heart rate variability, and enhanced sensitivity to the negative chronotropic effects of the muscarinic agonist carbachol. Similarly, loss of RGS6, but not RGS4, correlated with enhanced sensitivity of the M2R-IKACh signaling pathway in SAN cells to carbachol and a significant slowing of M2R-IKACh deactivation rate. Surprisingly, concurrent genetic ablation of RGS4 partially rescued some deficits observed in Rgs6(-/-) mice. These findings, together with those from an acute pharmacologic approach in SAN cells from Rgs6(-/-) and Gβ5(-/-) mice, suggest that the partial rescue of phenotypes in Rgs4(-/-):Rgs6(-/-) mice is attributable to another R7 RGS protein whose influence on M2R-IKACh signaling is masked by RGS4. Thus, RGS6-Gβ5, but not RGS4, is the primary RGS modulator of parasympathetic HR regulation and SAN M2R-IKACh signaling in mice.
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Affiliation(s)
- Nicole Wydeven
- From the Department of Pharmacology, University of Minnesota, Minneapolis, Minnesota 55455 and
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48
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Storaska AJ, Mei JP, Wu M, Li M, Wade SM, Blazer LL, Sjögren B, Hopkins CR, Lindsley CW, Lin Z, Babcock JJ, McManus OB, Neubig RR. Reversible inhibitors of regulators of G-protein signaling identified in a high-throughput cell-based calcium signaling assay. Cell Signal 2013; 25:2848-55. [PMID: 24041654 DOI: 10.1016/j.cellsig.2013.09.007] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2013] [Accepted: 09/06/2013] [Indexed: 11/30/2022]
Abstract
Regulator of G-protein signaling (RGS) proteins potently suppress G-protein coupled receptor (GPCR) signal transduction by accelerating GTP hydrolysis on activated heterotrimeric G-protein α subunits. RGS4 is enriched in the CNS and is proposed as a therapeutic target for treatment of neuropathological states including epilepsy and Parkinson's disease. Therefore, identification of novel RGS4 inhibitors is of interest. An HEK293-FlpIn cell-line stably expressing M3-muscarinic receptor with doxycycline-regulated RGS4 expression was employed to identify compounds that inhibit RGS4-mediated suppression of M3-muscarinic receptor signaling. Over 300,000 compounds were screened for an ability to enhance Gαq-mediated calcium signaling in the presence of RGS4. Compounds that modulated the calcium response in a counter-screen in the absence of RGS4 were not pursued. Of the 1365 RGS4-dependent primary screen hits, thirteen compounds directly target the RGS-G-protein interaction in purified systems. All thirteen compounds lose activity against an RGS4 mutant lacking cysteines, indicating that covalent modification of free thiol groups on RGS4 is a common mechanism. Four compounds produce >85% inhibition of RGS4-G-protein binding at 100μM, yet are >50% reversible within a ten-minute time frame. The four reversible compounds significantly alter the thermal melting temperature of RGS4, but not G-protein, indicating that inhibition is occurring through interaction with the RGS protein. The HEK cell-line employed for this study provides a powerful tool for efficiently identifying RGS-specific modulators within the context of a GPCR signaling pathway. As a result, several new reversible, cell-active RGS4 inhibitors have been identified for use in future biological studies.
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Affiliation(s)
- Andrew J Storaska
- Department of Pharmacology, University of Michigan, Ann Arbor, MI 48109, USA
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49
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Li SJ, Li Y, Cui SC, Qi Y, Zhao JJ, Liu XY, Xu P, Chen XH. Splicing factor transformer-2β (Tra2β) regulates the expression of regulator of G protein signaling 4 (RGS4) gene and is induced by morphine. PLoS One 2013; 8:e72220. [PMID: 23977258 PMCID: PMC3747076 DOI: 10.1371/journal.pone.0072220] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2013] [Accepted: 07/08/2013] [Indexed: 12/19/2022] Open
Abstract
Regulator of G protein signaling 4 (RGS4) is a critical modulator of G protein-coupled receptor (GPCR)-mediated signaling and plays important roles in many neural process and diseases. Particularly, drug-induced alteration in RGS4 protein levels is associated with acute and chronic effects of drugs of abuse. However, the precise mechanism underlying the regulation of RGS4 expression is largely unknown. Here, we demonstrated that the expression of RGS4 gene was subject to regulation by alternative splicing of the exon 6. Transformer-2β (Tra2β), an important splicing factor, bound to RGS4 mRNA and increased the relative level of RGS4-1 mRNA isoform by enhancing the inclusion of exon 6. Meanwhile, Tra2β increased the expression of full-length RGS4 protein. In rat brain, Tra2β was co-localized with RGS4 in multiple opioid action-related brain regions. In addition, the acute and chronic morphine treatment induced alteration in the expression level of Tra2β in rat locus coerulus (LC) in parallel to that of RGS4 proteins. It suggests that induction of this splicing factor may contribute to the change of RGS4 level elicited by morphine. Taken together, the results provide the evidence demonstrating the function of Tra2β as a new mediator in opioid-induced signaling pathway via regulating RGS4 expression.
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Affiliation(s)
- Shu-Jing Li
- State Key Laboratory of Medical Neurobiology and Department of Neurobiology,School of Basic Medical Sciences, Shanghai Medical College of Fudan University, Shanghai, China
- Laboratory of Genomic Physiology and Institutes of Brain Science, Shanghai Medical College of Fudan University, Shanghai, China
| | - Ya Li
- State Key Laboratory of Medical Neurobiology and Department of Neurobiology,School of Basic Medical Sciences, Shanghai Medical College of Fudan University, Shanghai, China
| | - Shi-chao Cui
- State Key Laboratory of Medical Neurobiology and Department of Neurobiology,School of Basic Medical Sciences, Shanghai Medical College of Fudan University, Shanghai, China
| | - Yao Qi
- State Key Laboratory of Medical Neurobiology and Department of Neurobiology,School of Basic Medical Sciences, Shanghai Medical College of Fudan University, Shanghai, China
| | - Jing-Jing Zhao
- State Key Laboratory of Medical Neurobiology and Department of Neurobiology,School of Basic Medical Sciences, Shanghai Medical College of Fudan University, Shanghai, China
| | - Xiao-Yan Liu
- State Key Laboratory of Medical Neurobiology and Department of Neurobiology,School of Basic Medical Sciences, Shanghai Medical College of Fudan University, Shanghai, China
| | - Ping Xu
- State Key Laboratory of Medical Neurobiology and Department of Neurobiology,School of Basic Medical Sciences, Shanghai Medical College of Fudan University, Shanghai, China
| | - Xian-Hua Chen
- State Key Laboratory of Medical Neurobiology and Department of Neurobiology,School of Basic Medical Sciences, Shanghai Medical College of Fudan University, Shanghai, China
- Laboratory of Genomic Physiology and Institutes of Brain Science, Shanghai Medical College of Fudan University, Shanghai, China
- * E-mail:
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50
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Zhang P, Mende U. Functional role, mechanisms of regulation, and therapeutic potential of regulator of G protein signaling 2 in the heart. Trends Cardiovasc Med 2013; 24:85-93. [PMID: 23962825 DOI: 10.1016/j.tcm.2013.07.002] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/16/2013] [Revised: 07/08/2013] [Accepted: 07/10/2013] [Indexed: 12/22/2022]
Abstract
G protein-mediated signal transduction is essential for the regulation of cardiovascular function, including heart rate, growth, contraction, and vascular tone. Regulators of G protein Signaling (RGS proteins) fine-tune G protein-coupled receptor-induced signaling by regulating its magnitude and duration through direct interaction with the α subunits of heterotrimeric G proteins. Changes in the RGS protein expression and/or function in the heart often lead to pathophysiological changes and are associated with cardiac disease in animals and humans, including hypertrophy, fibrosis development, heart failure, and arrhythmias. This article focuses on Regulator of G protein Signaling 2 (RGS2), which is widely expressed in many tissues and is highly regulated in its expression and function. Most information to date has been obtained in biochemical, cellular, and animal studies, but data from humans is emerging. We review recent advances on the functional role of cardiovascular RGS2 and the mechanisms that determine its signaling selectivity, expression, and functionality. We highlight key unanswered questions and discuss the potential of RGS2 as a therapeutic target.
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Affiliation(s)
- Peng Zhang
- Cardiovascular Research Center, Cardiology Division, Rhode Island Hospital and Alpert Medical School of Brown University, Providence, RI, USA
| | - Ulrike Mende
- Cardiovascular Research Center, Cardiology Division, Rhode Island Hospital and Alpert Medical School of Brown University, Providence, RI, USA.
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