1
|
Roy S, Sinha S, Silas AJ, Ghassemian M, Kufareva I, Ghosh P. Growth factor-dependent phosphorylation of Gα i shapes canonical signaling by G protein-coupled receptors. Sci Signal 2024; 17:eade8041. [PMID: 38833528 DOI: 10.1126/scisignal.ade8041] [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: 09/11/2022] [Accepted: 05/17/2024] [Indexed: 06/06/2024]
Abstract
A long-standing question in the field of signal transduction is how distinct signaling pathways interact with each other to control cell behavior. Growth factor receptors and G protein-coupled receptors (GPCRs) are the two major signaling hubs in eukaryotes. Given that the mechanisms by which they signal independently have been extensively characterized, we investigated how they may cross-talk with each other. Using linear ion trap mass spectrometry and cell-based biophysical, biochemical, and phenotypic assays, we found at least three distinct ways in which epidermal growth factor affected canonical G protein signaling by the Gi-coupled GPCR CXCR4 through the phosphorylation of Gαi. Phosphomimicking mutations in two residues in the αE helix of Gαi (tyrosine-154/tyrosine-155) suppressed agonist-induced Gαi activation while promoting constitutive Gβγ signaling. Phosphomimicking mutations in the P loop (serine-44, serine-47, and threonine-48) suppressed Gi activation entirely, thus completely segregating growth factor and GPCR pathways. As expected, most of the phosphorylation events appeared to affect intrinsic properties of Gαi proteins, including conformational stability, nucleotide binding, and the ability to associate with and to release Gβγ. However, one phosphomimicking mutation, targeting the carboxyl-terminal residue tyrosine-320, promoted mislocalization of Gαi from the plasma membrane, a previously uncharacterized mechanism of suppressing GPCR signaling through G protein subcellular compartmentalization. Together, these findings elucidate not only how growth factor and chemokine signals cross-talk through the phosphorylation-dependent modulation of Gαi but also how such cross-talk may generate signal diversity.
Collapse
Affiliation(s)
- Suchismita Roy
- Department of Cellular and Molecular Medicine, University of California San Diego, San Diego, CA 92093, USA
| | - Saptarshi Sinha
- Department of Cellular and Molecular Medicine, University of California San Diego, San Diego, CA 92093, USA
| | - Ananta James Silas
- Department of Cellular and Molecular Medicine, University of California San Diego, San Diego, CA 92093, USA
| | - Majid Ghassemian
- Department of Chemistry and Biochemistry, Biomolecular and Proteomics Mass Spectrometry Facility, University of California San Diego, San Diego, CA 92093, USA
| | - Irina Kufareva
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California San Diego, San Diego, CA 92093, USA
| | - Pradipta Ghosh
- Department of Cellular and Molecular Medicine, University of California San Diego, San Diego, CA 92093, USA
- Department of Medicine, University of California San Diego, San Diego, CA 92093, USA
- Moores Comprehensive Cancer Center, University of California San Diego, San Diego, CA 92093, USA
| |
Collapse
|
2
|
Samadi M, Hales CA, Lustberg DJ, Farris S, Ross MR, Zhao M, Hepler JR, Harbin NH, Robinson ESJ, Banks PJ, Bashir ZI, Dudek SM. Mechanisms of mGluR-dependent plasticity in hippocampal area CA2. Hippocampus 2023; 33:730-744. [PMID: 36971428 PMCID: PMC10213158 DOI: 10.1002/hipo.23529] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2023] [Revised: 03/04/2023] [Accepted: 03/08/2023] [Indexed: 03/29/2023]
Abstract
Pyramidal cells in hippocampal area CA2 have synaptic properties that are distinct from the other CA subregions. Notably, this includes a lack of typical long-term potentiation of stratum radiatum synapses. CA2 neurons express high levels of several known and potential regulators of metabotropic glutamate receptor (mGluR)-dependent signaling including Striatal-Enriched Tyrosine Phosphatase (STEP) and several Regulator of G-protein Signaling (RGS) proteins, yet the functions of these proteins in regulating mGluR-dependent synaptic plasticity in CA2 are completely unknown. Thus, the aim of this study was to examine mGluR-dependent synaptic depression and to determine whether STEP and the RGS proteins RGS4 and RGS14 are involved. Using whole cell voltage-clamp recordings from mouse pyramidal cells, we found that mGluR agonist-induced long-term depression (mGluR-LTD) is more pronounced in CA2 compared with that observed in CA1. This mGluR-LTD in CA2 was found to be protein synthesis and STEP dependent, suggesting that CA2 mGluR-LTD shares mechanistic processes with those seen in CA1, but in addition, RGS14, but not RGS4, was essential for mGluR-LTD in CA2. In addition, we found that exogenous application of STEP could rescue mGluR-LTD in RGS14 KO slices. Supporting a role for CA2 synaptic plasticity in social cognition, we found that RGS14 KO mice had impaired social recognition memory as assessed in a social discrimination task. These results highlight possible roles for mGluRs, RGS14, and STEP in CA2-dependent behaviors, perhaps by biasing the dominant form of synaptic plasticity away from LTP and toward LTD in CA2.
Collapse
Affiliation(s)
- Mahsa Samadi
- School of Physiology, Pharmacology and Neuroscience, Biomedical Sciences BuildingUniversity Walk, University of BristolBristolUKBS8 1TD
- Neurobiology Laboratory, National Institute of Environmental Health Sciences (NIH)111 T.W. Alexander Drive, Research Triangle ParkDurhamNorth Carolina27709USA
- Present address:
Faculty Education Office, Faculty of Medicine, Imperial College London, Hammersmith Campus, Wolfson Education CentreLondonUKW12 0NN
| | - Claire A. Hales
- School of Physiology, Pharmacology and Neuroscience, Biomedical Sciences BuildingUniversity Walk, University of BristolBristolUKBS8 1TD
- Present address:
Department of Psychology, Djavad Mowafaghian Centre for Brain HealthUniversity of British Columbia2215, Wesbrook MallVancouverBritish ColumbiaV6T 1Z3Canada
| | - Daniel J. Lustberg
- Neurobiology Laboratory, National Institute of Environmental Health Sciences (NIH)111 T.W. Alexander Drive, Research Triangle ParkDurhamNorth Carolina27709USA
- Present address:
Mouse Pharmacology GroupPsychogenics Inc215 College RoadParamusNew Jersey07652USA
| | - Shannon Farris
- Neurobiology Laboratory, National Institute of Environmental Health Sciences (NIH)111 T.W. Alexander Drive, Research Triangle ParkDurhamNorth Carolina27709USA
- Present address:
Fralin Biomedical Research Institute at Virginia TechRoanokeVirginia24014USA
| | - Madeleine R. Ross
- Neurobiology Laboratory, National Institute of Environmental Health Sciences (NIH)111 T.W. Alexander Drive, Research Triangle ParkDurhamNorth Carolina27709USA
| | - Meilan Zhao
- Neurobiology Laboratory, National Institute of Environmental Health Sciences (NIH)111 T.W. Alexander Drive, Research Triangle ParkDurhamNorth Carolina27709USA
| | - John R. Hepler
- Department of Pharmacology and Chemical BiologyEmory University School of Medicine100 Woodruff CircleAtlantaGeorgia30322USA
| | - Nicholas H. Harbin
- Department of Pharmacology and Chemical BiologyEmory University School of Medicine100 Woodruff CircleAtlantaGeorgia30322USA
| | - Emma S. J. Robinson
- School of Physiology, Pharmacology and Neuroscience, Biomedical Sciences BuildingUniversity Walk, University of BristolBristolUKBS8 1TD
| | - Paul J. Banks
- School of Physiology, Pharmacology and Neuroscience, Biomedical Sciences BuildingUniversity Walk, University of BristolBristolUKBS8 1TD
| | - Zafar I. Bashir
- School of Physiology, Pharmacology and Neuroscience, Biomedical Sciences BuildingUniversity Walk, University of BristolBristolUKBS8 1TD
| | - Serena M. Dudek
- Neurobiology Laboratory, National Institute of Environmental Health Sciences (NIH)111 T.W. Alexander Drive, Research Triangle ParkDurhamNorth Carolina27709USA
| |
Collapse
|
3
|
Montanez-Miranda C, Bramlett SN, Hepler JR. RGS14 expression in CA2 hippocampus, amygdala, and basal ganglia: Implications for human brain physiology and disease. Hippocampus 2023; 33:166-181. [PMID: 36541898 PMCID: PMC9974931 DOI: 10.1002/hipo.23492] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2022] [Revised: 11/09/2022] [Accepted: 12/07/2022] [Indexed: 12/24/2022]
Abstract
RGS14 is a multifunctional scaffolding protein that is highly expressed within postsynaptic spines of pyramidal neurons in hippocampal area CA2. Known roles of RGS14 in CA2 include regulating G protein, H-Ras/ERK, and calcium signaling pathways to serve as a natural suppressor of synaptic plasticity and postsynaptic signaling. RGS14 also shows marked postsynaptic expression in major structures of the limbic system and basal ganglia, including the amygdala and both the ventral and dorsal subdivisions of the striatum. In this review, we discuss the signaling functions of RGS14 and its role in postsynaptic strength (long-term potentiation) and spine structural plasticity in CA2 hippocampal neurons, and how RGS14 suppression of plasticity impacts linked behaviors such as spatial learning, object memory, and fear conditioning. We also review RGS14 expression in the limbic system and basal ganglia and speculate on its possible roles in regulating plasticity in these regions, with a focus on behaviors related to emotion and motivation. Finally, we explore the functional implications of RGS14 in various brain circuits and speculate on its possible roles in certain disease states such as hippocampal seizures, addiction, and anxiety disorders.
Collapse
Affiliation(s)
| | | | - John R. Hepler
- Department of Pharmacology and Chemical Biology, Emory University School of Medicine, Atlanta, GA, 30322-3090
| |
Collapse
|
4
|
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.
Collapse
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
| |
Collapse
|
5
|
Friedman PA, Sneddon WB, Mamonova T, Montanez-Miranda C, Ramineni S, Harbin NH, Squires KE, Gefter JV, Magyar CE, Emlet DR, Hepler JR. RGS14 regulates PTH- and FGF23-sensitive NPT2A-mediated renal phosphate uptake via binding to the NHERF1 scaffolding protein. J Biol Chem 2022; 298:101836. [PMID: 35307350 PMCID: PMC9035407 DOI: 10.1016/j.jbc.2022.101836] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2021] [Revised: 03/04/2022] [Accepted: 03/06/2022] [Indexed: 02/06/2023] Open
Abstract
Phosphate homeostasis, mediated by dietary intake, renal absorption, and bone deposition, is incompletely understood because of the uncharacterized roles of numerous implicated protein factors. Here, we identified a novel role for one such element, regulator of G protein signaling 14 (RGS14), suggested by genome-wide association studies to associate with dysregulated Pi levels. We show that human RGS14 possesses a carboxy-terminal PDZ ligand required for sodium phosphate cotransporter 2a (NPT2A) and sodium hydrogen exchanger regulatory factor-1 (NHERF1)-mediated renal Pi transport. In addition, we found using isotope uptake measurements combined with bioluminescence resonance energy transfer assays, siRNA knockdown, pull-down and overlay assays, and molecular modeling that secreted proteins parathyroid hormone (PTH) and fibroblast growth factor 23 inhibited Pi uptake by inducing dissociation of the NPT2A-NHERF1 complex. PTH failed to affect Pi transport in cells expressing RGS14, suggesting that it suppresses hormone-sensitive but not basal Pi uptake. Interestingly, RGS14 did not affect PTH-directed G protein activation or cAMP formation, implying a postreceptor site of action. Further pull-down experiments and direct binding assays indicated that NPT2A and RGS14 bind distinct PDZ domains on NHERF1. We showed that RGS14 expression in human renal proximal tubule epithelial cells blocked the effects of PTH and fibroblast growth factor 23 and stabilized the NPT2A-NHERF1 complex. In contrast, RGS14 genetic variants bearing mutations in the PDZ ligand disrupted RGS14 binding to NHERF1 and subsequent PTH-sensitive Pi transport. In conclusion, these findings identify RGS14 as a novel regulator of hormone-sensitive Pi transport. The results suggest that changes in RGS14 function or abundance may contribute to the hormone resistance and hyperphosphatemia observed in kidney diseases.
Collapse
Affiliation(s)
- Peter A Friedman
- Laboratory for GPCR Biology, Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA; Department of Structural Biology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA.
| | - W Bruce Sneddon
- Laboratory for GPCR Biology, Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
| | - Tatyana Mamonova
- Laboratory for GPCR Biology, Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
| | - Carolina Montanez-Miranda
- Department of Pharmacology and Chemical Biology, Emory University School of Medicine, Atlanta, Georgia, USA
| | - Suneela Ramineni
- Department of Pharmacology and Chemical Biology, Emory University School of Medicine, Atlanta, Georgia, USA
| | - Nicholas H Harbin
- Department of Pharmacology and Chemical Biology, Emory University School of Medicine, Atlanta, Georgia, USA
| | - Katherine E Squires
- Department of Pharmacology and Chemical Biology, Emory University School of Medicine, Atlanta, Georgia, USA
| | - Julia V Gefter
- Laboratory for GPCR Biology, Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
| | - Clara E Magyar
- Department of Pathology and Laboratory Medicine, The David Geffen School of Medicine at UCLA, Los Angeles, California, USA
| | - David R Emlet
- Center for Critical Care Nephrology, Department of Critical Care Medicine, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
| | - John R Hepler
- Department of Pharmacology and Chemical Biology, Emory University School of Medicine, Atlanta, Georgia, USA.
| |
Collapse
|
6
|
RGS14 Regulation of Post-Synaptic Signaling and Spine Plasticity in Brain. Int J Mol Sci 2021; 22:ijms22136823. [PMID: 34201943 PMCID: PMC8268017 DOI: 10.3390/ijms22136823] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2021] [Revised: 06/12/2021] [Accepted: 06/14/2021] [Indexed: 02/06/2023] Open
Abstract
The regulator of G-protein signaling 14 (RGS14) is a multifunctional signaling protein that regulates post synaptic plasticity in neurons. RGS14 is expressed in the brain regions essential for learning, memory, emotion, and stimulus-induced behaviors, including the basal ganglia, limbic system, and cortex. Behaviorally, RGS14 regulates spatial and object memory, female-specific responses to cued fear conditioning, and environmental- and psychostimulant-induced locomotion. At the cellular level, RGS14 acts as a scaffolding protein that integrates G protein, Ras/ERK, and calcium/calmodulin signaling pathways essential for spine plasticity and cell signaling, allowing RGS14 to naturally suppress long-term potentiation (LTP) and structural plasticity in hippocampal area CA2 pyramidal cells. Recent proteomics findings indicate that RGS14 also engages the actomyosin system in the brain, perhaps to impact spine morphogenesis. Of note, RGS14 is also a nucleocytoplasmic shuttling protein, where its role in the nucleus remains uncertain. Balanced nuclear import/export and dendritic spine localization are likely essential for RGS14 neuronal functions as a regulator of synaptic plasticity. Supporting this idea, human genetic variants disrupting RGS14 localization also disrupt RGS14’s effects on plasticity. This review will focus on the known and unexplored roles of RGS14 in cell signaling, physiology, disease and behavior.
Collapse
|
7
|
Ear J, Abd El-Hafeez AA, Roy S, Ngo T, Rajapakse N, Choi J, Khandelwal S, Ghassemian M, McCaffrey L, Kufareva I, Sahoo D, Ghosh P. A long isoform of GIV/Girdin contains a PDZ-binding module that regulates localization and G-protein binding. J Biol Chem 2021; 296:100493. [PMID: 33675748 PMCID: PMC8042451 DOI: 10.1016/j.jbc.2021.100493] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2021] [Revised: 02/19/2021] [Accepted: 02/26/2021] [Indexed: 11/28/2022] Open
Abstract
PDZ domains are one of the most abundant protein domains in eukaryotes and are frequently found on junction-localized scaffold proteins. Various signaling molecules bind to PDZ proteins via PDZ-binding motifs (PBM) and fine-tune cellular signaling. However, how such interaction affects protein function is difficult to predict and must be solved empirically. Here we describe a long isoform of the guanine nucleotide exchange factor GIV/Girdin (CCDC88A) that we named GIV-L, which is conserved throughout evolution, from invertebrates to vertebrates, and contains a PBM. Unlike GIV, which lacks PBM and is cytosolic, GIV-L localizes onto cell junctions and has a PDZ interactome (as shown through annotating Human Cell Map and BioID-proximity labeling studies), which impacts GIV-L's ability to bind and activate trimeric G-protein, Gαi, through its guanine-nucleotide exchange modulator (GEM) module. This GEM module is found exclusively in vertebrates. We propose that the two functional modules in GIV may have evolved sequentially: the ability to bind PDZ proteins via the PBM evolved earlier in invertebrates, whereas G-protein binding and activation may have evolved later only among vertebrates. Phenotypic studies in Caco-2 cells revealed that GIV and GIV-L may have antagonistic effects on cell growth, proliferation (cell cycle), and survival. Immunohistochemical analysis in human colon tissues showed that GIV expression increases with a concomitant decrease in GIV-L during cancer initiation. Taken together, these findings reveal how regulation in GIV/CCDC88A transcript helps to achieve protein modularity, which allows the protein to play opposing roles either as a tumor suppressor (GIV-L) or as an oncogene (GIV).
Collapse
Affiliation(s)
- Jason Ear
- Department of Cellular and Molecular Medicine, University of California San Diego, La Jolla, California, USA; Biological Sciences Department, California State Polytechnic University, Pomona, California, USA.
| | - Amer Ali Abd El-Hafeez
- Department of Cellular and Molecular Medicine, University of California San Diego, La Jolla, California, USA; Pharmacology and Experimental Oncology Unit, Cancer Biology Department, National Cancer Institute, Cairo University, Cairo, Egypt
| | - Suchismita Roy
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California San Diego, La Jolla, California, USA
| | - Tony Ngo
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California San Diego, La Jolla, California, USA
| | - Navin Rajapakse
- Department of Cellular and Molecular Medicine, University of California San Diego, La Jolla, California, USA
| | - Julie Choi
- Department of Cellular and Molecular Medicine, University of California San Diego, La Jolla, California, USA
| | - Soni Khandelwal
- Department of Pediatrics, University of California San Diego, La Jolla, California, USA
| | - Majid Ghassemian
- Department of Chemistry and Biochemistry, University of California San Diego, La Jolla, California, USA
| | - Luke McCaffrey
- Rosalind and Morris Goodman Cancer Research Centre, McGill University, Montreal, Canada; Gerald Bronfman Department of Oncology, McGill University, Montreal, Canada
| | - Irina Kufareva
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California San Diego, La Jolla, California, USA
| | - Debashis Sahoo
- Department of Pediatrics, University of California San Diego, La Jolla, California, USA
| | - Pradipta Ghosh
- Department of Cellular and Molecular Medicine, University of California San Diego, La Jolla, California, USA; Department of Medicine, University of California San Diego, La Jolla, California, USA; Rebecca and John Moore Comprehensive Cancer Center, University of California San Diego, La Jolla, California, USA; Veterans Affairs Medical Center, La Jolla, California, USA.
| |
Collapse
|
8
|
The PDZ motif peptide of ZO-1 attenuates Pseudomonas aeruginosa LPS-induced airway inflammation. Sci Rep 2020; 10:19644. [PMID: 33184397 PMCID: PMC7665049 DOI: 10.1038/s41598-020-76883-9] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2020] [Accepted: 11/02/2020] [Indexed: 11/24/2022] Open
Abstract
Pseudomonas aeruginosa is known to play a role in many human diseases. Therefore, examining the negative control mechanisms of tight junction protein ZO-1 on the exotoxin LPS of P. aeruginosa-induced diseases could be critical in the development of novel therapeutics. We found that ZO-1 expression dramatically decreased in inflammatory human lung tissues. Interestingly, PDZ1 deletion of the PDZ domain in the ZO-1 protein dramatically decreased LPS-induced F-actin formation and increased the expression of genes for pro-inflammatory cytokines, but not PDZ2 and PDZ3 of the ZO-1 protein. We also found that the consensus PDZ peptide (based on PDZ1) of ZO-1 down-regulates the expression of pro-inflammatory cytokine genes and F-actin formation; in contrast, the GG24,25AA mutant PDZ peptide cannot control these genes. LPS activates IL-8 secretion extracellularly in a time-dependent manner, while the secretion is inhibited by PDZ peptide. Whereas increased IL-8 secretion by LPS activates the CXCR2 receptor, overexpressed RGS12 negatively regulates LPS-induced CXCR2/IL-8 signaling. The PDZ peptide also decreases LPS-induced inflammatory cell populations, pro-inflammatory cytokine gene expression, and TEER in bronchoalveolar lavage fluid and cultured alveolar macrophages. Collectively, we suggest that the PDZ peptide may be a potential therapeutic for bacteria-induced respiratory diseases.
Collapse
|
9
|
Ear J, Ali Abd El-hafeez A, Roy S, Ngo T, Rajapakse N, Choi J, Khandelwal S, Ghassemian M, Mccaffrey L, Kufareva I, Sahoo D, Ghosh P. Evolution of Modularity, Interactome and Functions of GIV/Girdin (CCDC88A) from Invertebrates to Vertebrates.. [DOI: 10.1101/2020.09.28.317172] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/02/2023]
Abstract
AbstractPDZ domains are one of the most abundant protein domains in eukaryotes and frequently found on junction-localized scaffold proteins. Various signaling molecules bind to PDZ proteins via PDZ-binding motifs (PBM) and finetune cellular signaling. Here we describe the presence of a PBM on GIV/Girdin (CCDC88A) that is conserved throughout evolution, from invertebrates to vertebrates, and is generated as a long isoform-variant in humans, which we named GIV-L. Unlike GIV, which lacks PBM and is cytosolic, GIV-L localizes to the cell junctions, and has a unique PDZ-interactome, which impacts GIV-L’s ability to bind and activate trimeric G-protein, Gi through its guanine-nucleotide exchange modulator (GEM) module; the GEM module is found exclusively in vertebrates. Thus, the two functional modules in GIV evolved sequentially: the ability to bind PDZ proteins via the PBM evolved earlier in invertebrates, whereas G-protein binding and activation may have evolved later only among vertebrates. Phenotypic studies in Caco-2 cells revealed that GIV and GIV-L may have antagonistic effects on cell growth, proliferation (cell cycle), and survival. Immunohistochemical analyses in human colon tissues showed that GIV expression increases with a concomitant decrease in GIV-L during cancer initiation. Taken together, these findings reveal how GIV/CCDC88A in humans displays evolutionary flexibility in modularity, which allows the resultant isoforms to play opposing roles either as a tumor suppressor (GIV-L) or as an oncogene (GIV).
Collapse
|
10
|
DiGiacomo V, Maziarz M, Luebbers A, Norris JM, Laksono P, Garcia-Marcos M. Probing the mutational landscape of regulators of G protein signaling proteins in cancer. Sci Signal 2020; 13:13/617/eaax8620. [PMID: 32019900 DOI: 10.1126/scisignal.aax8620] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The advent of deep-sequencing techniques has revealed that mutations in G protein-coupled receptor (GPCR) signaling pathways in cancer are more prominent than was previously appreciated. An emergent theme is that cancer-associated mutations tend to cause enhanced GPCR pathway activation to favor oncogenicity. Regulators of G protein signaling (RGS) proteins are critical modulators of GPCR signaling that dampen the activity of heterotrimeric G proteins through their GTPase-accelerating protein (GAP) activity, which is conferred by a conserved domain dubbed the "RGS-box." Here, we developed an experimental pipeline to systematically assess the mutational landscape of RGS GAPs in cancer. A pan-cancer bioinformatics analysis of the 20 RGS domains with GAP activity revealed hundreds of low-frequency mutations spread throughout the conserved RGS domain structure with a slight enrichment at positions that interface with G proteins. We empirically tested multiple mutations representing all RGS GAP subfamilies and sampling both G protein interface and noninterface positions with a scalable, yeast-based assay. Last, a subset of mutants was validated using G protein activity biosensors in mammalian cells. Our findings reveal that a sizable fraction of RGS protein mutations leads to a loss of function through various mechanisms, including disruption of the G protein-binding interface, loss of protein stability, or allosteric effects on G protein coupling. Moreover, our results also validate a scalable pipeline for the rapid characterization of cancer-associated mutations in RGS proteins.
Collapse
Affiliation(s)
- Vincent DiGiacomo
- Department of Biochemistry, Boston University School of Medicine, Boston, MA 02118, USA
| | - Marcin Maziarz
- Department of Biochemistry, Boston University School of Medicine, Boston, MA 02118, USA
| | - Alex Luebbers
- Department of Biochemistry, Boston University School of Medicine, Boston, MA 02118, USA
| | - Jillian M Norris
- Department of Biochemistry, Boston University School of Medicine, Boston, MA 02118, USA
| | - Pandu Laksono
- Department of Biochemistry, Boston University School of Medicine, Boston, MA 02118, USA
| | - Mikel Garcia-Marcos
- Department of Biochemistry, Boston University School of Medicine, Boston, MA 02118, USA.
| |
Collapse
|
11
|
Gerber KJ, Squires KE, Hepler JR. 14-3-3γ binds regulator of G protein signaling 14 (RGS14) at distinct sites to inhibit the RGS14:Gα i-AlF 4- signaling complex and RGS14 nuclear localization. J Biol Chem 2018; 293:14616-14631. [PMID: 30093406 DOI: 10.1074/jbc.ra118.002816] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2018] [Revised: 07/23/2018] [Indexed: 11/06/2022] Open
Abstract
Regulator of G protein signaling 14 (RGS14) is a multifunctional brain scaffolding protein that integrates G protein and Ras/ERK signaling pathways. It is also a nucleocytoplasmic shuttling protein. RGS14 binds active Gαi/o via its RGS domain, Raf and active H-Ras-GTP via its R1 Ras-binding domain (RBD), and inactive Gαi1/3 via its G protein regulatory (GPR) domain. RGS14 suppresses long-term potentiation (LTP) in the CA2 region of the hippocampus, thereby regulating hippocampally based learning and memory. The 14-3-3 family of proteins is necessary for hippocampal LTP and associative learning and memory. Here, we show direct interaction between RGS14 and 14-3-3γ at two distinct sties, one phosphorylation-independent and the other phosphorylation-dependent at Ser-218 that is markedly potentiated by signaling downstream of active H-Ras. Using bioluminescence resonance energy transfer (BRET), we show that the pSer-218-dependent RGS14/14-3-3γ interaction inhibits active Gαi1-AlF4- binding to the RGS domain of RGS14 but has no effect on active H-Ras and inactive Gαi1-GDP binding to RGS14. By contrast, the phosphorylation-independent binding of 14-3-3 has no effect on RGS14/Gαi interactions but, instead, inhibits (directly or indirectly) RGS14 nuclear import and nucleocytoplasmic shuttling. Together, our findings describe a novel mechanism of negative regulation of RGS14 functions, specifically interactions with active Gαi and nuclear import, while leaving the function of other RGS14 domains intact. Ongoing studies will further elucidate the physiological function of this interaction between RGS14 and 14-3-3γ, providing insight into the functions of both RGS14 and 14-3-3 in their roles in modulating synaptic plasticity in the hippocampus.
Collapse
Affiliation(s)
- Kyle J Gerber
- From the Department of Pharmacology, Emory University School of Medicine, Atlanta, Georgia 30322
| | - Katherine E Squires
- From the Department of Pharmacology, Emory University School of Medicine, Atlanta, Georgia 30322
| | - John R Hepler
- From the Department of Pharmacology, Emory University School of Medicine, Atlanta, Georgia 30322
| |
Collapse
|
12
|
Regulator of G protein signaling 14 (RGS14) is expressed pre- and postsynaptically in neurons of hippocampus, basal ganglia, and amygdala of monkey and human brain. Brain Struct Funct 2017; 223:233-253. [PMID: 28776200 DOI: 10.1007/s00429-017-1487-y] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2017] [Accepted: 07/26/2017] [Indexed: 12/18/2022]
Abstract
Regulator of G protein signaling 14 (RGS14) is a multifunctional signaling protein primarily expressed in mouse pyramidal neurons of hippocampal area CA2 where it regulates synaptic plasticity important for learning and memory. However, very little is known about RGS14 protein expression in the primate brain. Here, we validate the specificity of a new polyclonal RGS14 antibody that recognizes not only full-length RGS14 protein in primate, but also lower molecular weight forms of RGS14 protein matching previously predicted human splice variants. These putative RGS14 variants along with full-length RGS14 are expressed in the primate striatum. By contrast, only full-length RGS14 is expressed in hippocampus, and shorter variants are completely absent in rodent brain. We report that RGS14 protein immunoreactivity is found both pre- and postsynaptically in multiple neuron populations throughout hippocampal area CA1 and CA2, caudate nucleus, putamen, globus pallidus, substantia nigra, and amygdala in adult rhesus monkeys. A similar cellular expression pattern of RGS14 in the monkey striatum and hippocampus was further confirmed in humans. Our electron microscopy data show for the first time that RGS14 immunostaining localizes within nuclei of striatal neurons in monkeys. Taken together, these findings suggest new pre- and postsynaptic regulatory functions of RGS14 and RGS14 variants, specific to the primate brain, and provide evidence for unconventional roles of RGS14 in the nuclei of striatal neurons potentially important for human neurophysiology and disease.
Collapse
|
13
|
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.
| |
Collapse
|
14
|
Brown NE, Lambert NA, Hepler JR. RGS14 regulates the lifetime of G α-GTP signaling but does not prolong G βγ signaling following receptor activation in live cells. Pharmacol Res Perspect 2016; 4:e00249. [PMID: 27713821 PMCID: PMC5045935 DOI: 10.1002/prp2.249] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2016] [Accepted: 06/28/2016] [Indexed: 12/17/2022] Open
Abstract
RGS14 is a multifunctional scaffolding protein possessing two distinct G protein interaction sites including a regulator of G protein signaling (RGS) domain that acts as a GTPase activating protein (GAP) to deactivate Gαi/o‐GTP proteins, and a G protein regulatory (GPR) motif that binds inactive Gαi1/3‐GDP proteins independent of Gβγ. GPR interactions with Gαi recruit RGS14 to the plasma membrane to interact with Gαi‐linked GPCRs and regulate Gαi signaling. While RGS14 actions on Gα proteins are well characterized, consequent effects on Gβγ signaling remain unknown. Conventional RGS proteins act as dedicated GAPs to deactivate Gα and Gβγ signaling following receptor activation. RGS14 may do the same or, alternatively, may coordinate its actions to deactivate Gα‐GTP with the RGS domain and then capture the same Gα‐GDP via its GPR motif to prevent heterotrimer reassociation and prolong Gβγ signaling. To test this idea, we compared the regulation of G protein activation and deactivation kinetics by a conventional RGS protein, RGS4, and RGS14 in response to GPCR agonist/antagonist treatment utilizing bioluminescence resonance energy transfer (BRET). Co‐expression of either RGS4 or RGS14 inhibited the release of free Gβγ after agonist stimulation and increased the deactivation rate of Gα, consistent with their roles as GTPase activating proteins (GAPs). Overexpression of inactive Gαi1 to recruit RGS14 to the plasma membrane did not alter RGS14′s capacity to act as a GAP for a second Gαo protein. These results demonstrate the role of RGS14 as a dedicated GAP and suggest that the G protein regulatory (GPR) motif functions independently of the RGS domain and is silent in regulating GAP activity in a cellular context.
Collapse
Affiliation(s)
- Nicole E Brown
- Department of Pharmacology Emory University School of Medicine Atlanta Georgia 30322
| | - Nevin A Lambert
- Department of Pharmacology and Toxicology Medical College of Georgia at Augusta University Augusta Georgia 30912
| | - John R Hepler
- Department of Pharmacology Emory University School of Medicine Atlanta Georgia 30322
| |
Collapse
|