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Morris CW, Watkins DS, Shah NR, Pennington T, Hens B, Qi G, Doud EH, Mosley AL, Atwood BK, Baucum AJ. Spinophilin Limits Metabotropic Glutamate Receptor 5 Scaffolding to the Postsynaptic Density and Cell Type Specifically Mediates Excessive Grooming. Biol Psychiatry 2023; 93:976-988. [PMID: 36822932 PMCID: PMC10191892 DOI: 10.1016/j.biopsych.2022.12.008] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/24/2022] [Revised: 12/02/2022] [Accepted: 12/07/2022] [Indexed: 12/15/2022]
Abstract
BACKGROUND Grooming dysfunction is a hallmark of the obsessive-compulsive spectrum disorder trichotillomania. Numerous preclinical studies have utilized SAPAP3-deficient mice for understanding the neurobiology of repetitive grooming, suggesting that excessive grooming is caused by increased metabotropic glutamate receptor 5 (mGluR5) activity in striatal direct- and indirect-pathway medium spiny neurons (MSNs). However, the MSN subtype-specific signaling mechanisms that mediate mGluR5-dependent adaptations underlying excessive grooming are not fully understood. Here, we investigated the MSN subtype-specific roles of the striatal signaling hub protein spinophilin in mediating repetitive motor dysfunction associated with mGluR5 function. METHODS Quantitative proteomics and immunoblotting were utilized to identify how spinophilin impacts mGluR5 phosphorylation and protein interaction changes. Plasticity and repetitive motor dysfunction associated with mGluR5 action were measured using our novel conditional spinophilin mouse model in which spinophilin was knocked out from striatal direct-pathway MSNs and/or indirect-pathway MSNs. RESULTS Loss of spinophilin only in indirect-pathway MSNs decreased performance of a novel motor repertoire, but loss of spinophilin in either MSN subtype abrogated striatal plasticity associated with mGluR5 function and prevented excessive grooming caused by SAPAP3 knockout mice or treatment with the mGluR5-specific positive allosteric modulator VU0360172 without impacting locomotion-relevant behavior. Biochemically, we determined that the spinophilin-mGluR5 interaction correlates with grooming behavior and that loss of spinophilin shifts mGluR5 interactions from lipid raft-associated proteins toward postsynaptic density proteins implicated in psychiatric disorders. CONCLUSIONS These results identify spinophilin as a novel striatal signaling hub molecule in MSNs that cell subtype specifically mediates behavioral, functional, and molecular adaptations associated with repetitive motor dysfunction in psychiatric disorders.
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Affiliation(s)
- Cameron W Morris
- Medical Neurosciences Graduate Program, Indiana University School of Medicine, Indianapolis, Indiana
| | - Darryl S Watkins
- Medical Neurosciences Graduate Program, Indiana University School of Medicine, Indianapolis, Indiana
| | - Nikhil R Shah
- Medical Neurosciences Graduate Program, Indiana University School of Medicine, Indianapolis, Indiana; Medical Scientists Training Program, Indiana University School of Medicine, Indianapolis, Indiana
| | - Taylor Pennington
- Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis, Indiana
| | - Basant Hens
- Department of Pharmacology and Toxicology, Indiana University School of Medicine, Indianapolis, Indiana
| | - Guihong Qi
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, Indiana; Center for Proteome Analysis, Indiana University School of Medicine, Indianapolis, Indiana
| | - Emma H Doud
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, Indiana; Center for Proteome Analysis, Indiana University School of Medicine, Indianapolis, Indiana; Melvin and Bren Simon Comprehensive Cancer Center, Indiana University School of Medicine, Indianapolis, Indiana
| | - Amber L Mosley
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, Indiana; Center for Proteome Analysis, Indiana University School of Medicine, Indianapolis, Indiana; Melvin and Bren Simon Comprehensive Cancer Center, Indiana University School of Medicine, Indianapolis, Indiana; Center for Computational Biology and Bioinformatics, Indiana University School of Medicine, Indianapolis, Indiana
| | - Brady K Atwood
- Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis, Indiana; Department of Pharmacology and Toxicology, Indiana University School of Medicine, Indianapolis, Indiana
| | - Anthony J Baucum
- Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis, Indiana; Department of Pharmacology and Toxicology, Indiana University School of Medicine, Indianapolis, Indiana; Department of Biology, Indiana University-Purdue University Indianapolis, Indianapolis, Indiana.
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Darira SV, Sutton LP. The interaction, mechanism and function of GPR158-RGS7 cross-talk. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2022; 193:167-176. [PMID: 36357076 DOI: 10.1016/bs.pmbts.2022.06.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
GPR158 is an orphan G protein-coupled receptor (GPCR) that is broadly expressed in the brain and displays unique structural characteristics and signaling mechanisms. GPR158 is a binding partner for the regulator of G protein signaling 7 (RGS7) and augments its expression, subcellular localization, and catalytic activity. Recent cryo-electron microscopy (cryo-EM) studies have revealed the structure of GPR158 alone and in complex with RGS7. The GPR158-RGS7 complex is shown to be regulated by chronic stress exposure and is a modulator of stress-induced depression. This review highlights the signaling mechanism and function of GPR158-RGS7 and provides a context for the unique formation of GPCR-RGS complexes.
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Affiliation(s)
- Shradha V Darira
- Department of Biological Sciences, University of Maryland Baltimore County, Baltimore, MD, United States
| | - Laurie P Sutton
- Department of Biological Sciences, University of Maryland Baltimore County, Baltimore, MD, United States.
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Dunn HA, Ferguson SSG. PDZ Protein Regulation of G Protein–Coupled Receptor Trafficking and Signaling Pathways. Mol Pharmacol 2015; 88:624-39. [DOI: 10.1124/mol.115.098509] [Citation(s) in RCA: 82] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2015] [Accepted: 03/25/2015] [Indexed: 01/03/2023] Open
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Fourla DD, Papakonstantinou MP, Vrana SM, Georgoussi Z. Selective interactions of spinophilin with the C-terminal domains of the δ- and μ-opioid receptors and G proteins differentially modulate opioid receptor signaling. Cell Signal 2012; 24:2315-28. [PMID: 22922354 DOI: 10.1016/j.cellsig.2012.08.002] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2012] [Revised: 07/31/2012] [Accepted: 08/08/2012] [Indexed: 11/26/2022]
Abstract
Previous studies have shown that the intracellular domains of opioid receptors serve as platforms for the formation of a multi-component signaling complex consisting of various interacting partners (Leontiadis et al., 2009, Cell Signal. 21, 1218-1228; Georganta et al., 2010, Neuropharmacology, 59(3), 139-148). In the present study we demonstrate that spinophilin a dendritic-spine enriched scaffold protein associates with δ- and μ-opioid receptors (δ-ΟR, μ-OR) constitutively in HEK293 an interaction that is altered upon agonist administration and enhanced upon forskolin treatment for both μ-OR and δ-ΟR. Spinophilin association with the opioid receptors is mediated via the third intracellular loop and a conserved region of the C-terminal tails. The portion of spinophilin responsible for interaction with the δ-OR and μ-OR is narrowed to a region encompassing amino acids 151-444. Spinophilin, RGS4, Gα and Gβγ subunits of G proteins form a multi-protein complex using specific regions of spinophilin and a conserved amino acid stretch of the C-terminal tails of both δ-μ-ORs. Expression of spinophilin in HEK293 cells potentiated DPDPE-mediated adenylyl-cyclase inhibition of δ-OR leaving unaffected the levels of cAMP accumulation mediated by the μ-OR. Moreover, measurements of extracellular signal regulated kinase (ERK1,2) phosphorylation indicated that the presence of spinophilin attenuated agonist-driven ERK1,2 phosphorylation mediated upon activation of the δ-OR but not the μ-OR. Collectively, these findings suggest that spinophilin associates with both δ- and μ-ΟR and G protein subunits in HEK293 cells participating in a multimeric signaling complex that displays a differential regulatory role in opioid receptor signaling.
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Affiliation(s)
- Danai-Dionysia Fourla
- Laboratory of Cellular Signalling and Molecular Pharmacology, Institute of Biosciences and Applications, National Centre for Scientific Research Demokritos, Athens, Greece
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Brass LF, Wannemacher KM, Ma P, Stalker TJ. Regulating thrombus growth and stability to achieve an optimal response to injury. J Thromb Haemost 2011; 9 Suppl 1:66-75. [PMID: 21781243 PMCID: PMC3422128 DOI: 10.1111/j.1538-7836.2011.04364.x] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
An optimal platelet response to injury can be defined as one in which blood loss is restrained and haemostasis is achieved without the penalty of further tissue damage caused by unwarranted vascular occlusion. This brief review considers some of the ways in which thrombus growth and stability can be regulated so that an optimal platelet response can be achieved in vivo. Three related topics are considered. The first focuses on intracellular mechanisms that regulate the early events of platelet activation downstream of G protein coupled receptors for agonists such as thrombin, thromboxane A(2) and ADP. The second considers the ways in which signalling events that are dependent on stable contacts between platelets can influence the state of platelet activation and thus affect thrombus growth and stability. The third focuses on the changes that are experienced by platelets as they move from their normal environment in freely-flowing plasma to a very different environment within the growing haemostatic plug, an environment in which the narrowing gaps and junctions between platelets not only facilitate communication, but also increasingly limit both the penetration of plasma and the exodus of platelet-derived bioactive molecules.
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Affiliation(s)
- L F Brass
- Department of Medicine and Pharmacology, University of Pennsylvania School of Medicine, Philadelphia, PA 19104, USA
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Laroche G, Giguère PM, Roth BL, Trejo J, Siderovski DP. RNA interference screen for RGS protein specificity at muscarinic and protease-activated receptors reveals bidirectional modulation of signaling. Am J Physiol Cell Physiol 2010; 299:C654-64. [PMID: 20573995 PMCID: PMC2944319 DOI: 10.1152/ajpcell.00441.2009] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2009] [Accepted: 06/23/2010] [Indexed: 01/08/2023]
Abstract
Regulator of G protein signaling (RGS) proteins are considered key modulators of G protein-coupled receptor (GPCR)-mediated signal transduction. These proteins act directly on Galpha subunits in vitro to increase their intrinsic rate of GTP hydrolysis; this activity is central to the prevailing view of RGS proteins as negative regulators of agonist-initiated GPCR signaling. However, the specificities of action of particular RGS proteins toward specific GPCRs in an integrated cellular context remain unclear. Here, we developed a medium-throughput assay to address this question in a wholly endogenous context using RNA interference. We performed medium-throughput calcium mobilization assays of agonist-stimulated muscarinic acetylcholine and protease-activated receptors in human embryonic kidney 293 (HEK293) cells transfected with individual members of a "pooled duplex" short interfering RNA library targeting all conventional human RGS transcripts. Only knockdown of RGS11 increased both carbachol-mediated calcium mobilization and inositol phosphate accumulation. Surprisingly, we found that knockdown of RGS8 and RGS9, but not other conventional RGS proteins, significantly decreased carbachol-mediated calcium mobilization, whereas only RGS8 knockdown decreased protease-activated receptor-1 (PAR-1)-mediated calcium mobilization. Loss of responsiveness toward carbachol and PAR-1 agonist peptide upon RGS8 knockdown appears due, at least in part, to a loss in respective receptor cell surface expression, although this is not the case for RGS9 knockdown. Our data suggest a cellular role for RGS8 in the stable surface expression of M3 muscarinic acetylcholine receptor and PAR-1, as well as a specific and opposing set of functions for RGS9 and RGS11 in modulating carbachol responsiveness similar to that seen in Caenorhabditis elegans.
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Affiliation(s)
- Geneviève Laroche
- Department of Pharmacology, Univ. of North Carolina at Chapel Hill, Chapel Hill, NC, USA
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The presence of RGS8 in the microtubule fraction of the cerebellum. Neuroreport 2010. [DOI: 10.1097/wnr.0b013e3283350b06] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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McCoy KL, Hepler JR. Regulators of G protein signaling proteins as central components of G protein-coupled receptor signaling complexes. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2009; 86:49-74. [PMID: 20374713 DOI: 10.1016/s1877-1173(09)86003-1] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The regulators of G protein signaling (RGS) proteins bind directly to G protein alpha (Gα) subunits to regulate the signaling functions of Gα and their linked G protein-coupled receptors (GPCRs). Recent studies indicate that RGS proteins also interact with GPCRs, not just G proteins, to form preferred functional pairs. Interactions between GPCRs and RGS proteins may be direct or indirect (via a linker protein) and are dictated by the receptors, rather than the linked G proteins. Emerging models suggest that GPCRs serve as platforms for assembling an overlapping and distinct constellation of signaling proteins that perform receptor-specific signaling tasks. Compelling evidence now indicates that RGS proteins are central components of these GPCR signaling complexes. This review will outline recent discoveries of GPCR/RGS pairs as well as new data in support of the idea that GPCRs serve as platforms for the formation of multiprotein signaling complexes.
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Affiliation(s)
- Kelly L McCoy
- Department of Pharmacology, G205 Rollins Research Center, Emory University School of Medicine, Atlanta, Georgia 30322, USA
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