1
|
Yu L, Ling C, Li Y, Guo H, Xu A, Qian H, Li G. The Bombyx mori G protein β subunit 1 (BmGNβ1) gene inhibits BmNPV infection. J Invertebr Pathol 2024; 204:108097. [PMID: 38537687 DOI: 10.1016/j.jip.2024.108097] [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: 02/28/2023] [Revised: 03/22/2024] [Accepted: 03/24/2024] [Indexed: 04/01/2024]
Abstract
G protein β subunit 1 (GNβ1) has several functions, including cell growth regulation, the control of second messenger levels, and ion channel switching. Previous transcriptome analyses in our laboratory have shown that BmGNβ1 transcription is reduced following infection with Bombyx mori nucleopolyhedrovirus (BmNPV), but it is unknown what role this gene may have in the host response to BmNPV infection. In this study, the BmGNβ1 gene was cloned using the RACE method. After BmNPV infection, BmGNβ1 was downregulated in Baiyu strains in tissues such as the hemolymph and midgut. Indirect immunofluorescence showed that BmGNβ1 was localized to the cytoplasm. We further constructed a BmGNβ1-pIZ/V5-His-mCherry overexpression plasmid and designed siRNA to evaluate the role of BmGNβ1 in host response to infection. The results showed that BmGNβ1 overexpression inhibited BmNPV proliferation, while knockdown of BmGNβ1 was correlated with increased BmNPV proliferation. The siRNA-mediated reduction of BmGNβ1 was correlated with an increase in BmNPV infection of BmN cells, increased BmNPV vp39 transcription, and reduced survival time of BmNPV-infected B. mori. Overexpression of BmGNβ1 in BmN cells was also correlated with apoptosis and a modification in transcript levels of genes involved in host response to BmNPV infection (PI3K, AKT, Bmp53, BmFOXO, Caspase-1, Bmp21, BmPKN and BmCREB), suggesting that BmGNβ1 may influence the apoptotic host response of infected B. mori through the PI3K-AKT pathway. This study provides potential targets and theoretical support for breeding BmNPV-resistant silkworm varieties.
Collapse
Affiliation(s)
- Linyuan Yu
- The Sericultural Research Institute, Jiangsu University of Science and Technology, Zhenjiang, China
| | - Chenyu Ling
- The Sericultural Research Institute, Jiangsu University of Science and Technology, Zhenjiang, China
| | - Yizhu Li
- The Sericultural Research Institute, Jiangsu University of Science and Technology, Zhenjiang, China
| | - Huiduo Guo
- The Sericultural Research Institute, Jiangsu University of Science and Technology, Zhenjiang, China
| | - Anying Xu
- The Sericultural Research Institute, Jiangsu University of Science and Technology, Zhenjiang, China; The Key Laboratory of Silkworm and Mulberry Genetic Improvement, the Sericultural Research Institute, Chinese Academy of Agricultural Science, Zhenjiang 212018, Zhenjiang, China
| | - Heying Qian
- The Sericultural Research Institute, Jiangsu University of Science and Technology, Zhenjiang, China; The Key Laboratory of Silkworm and Mulberry Genetic Improvement, the Sericultural Research Institute, Chinese Academy of Agricultural Science, Zhenjiang 212018, Zhenjiang, China.
| | - Gang Li
- The Sericultural Research Institute, Jiangsu University of Science and Technology, Zhenjiang, China; The Key Laboratory of Silkworm and Mulberry Genetic Improvement, the Sericultural Research Institute, Chinese Academy of Agricultural Science, Zhenjiang 212018, Zhenjiang, China.
| |
Collapse
|
2
|
Chinnathambi S, Chidambaram H. G-protein coupled receptors regulates Tauopathy in neurodegeneration. ADVANCES IN PROTEIN CHEMISTRY AND STRUCTURAL BIOLOGY 2024; 141:467-493. [PMID: 38960483 DOI: 10.1016/bs.apcsb.2024.04.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/05/2024]
Abstract
In Alzheimer's disease, the microtubule-associated protein, Tau misfolds to form aggregates and filaments in the intra- and extracellular region of neuronal cells. Microglial cells are the resident brain macrophage cells involved in constant surveillance and activated by the extracellular deposits. Purinergic receptors are involved in the chemotactic migration of microglial cells towards the site of inflammation. From our recent study, we have observed that the microglial P2Y12 receptor is involved in phagocytosis of full-length Tau species such as monomers, oligomers and aggregates by actin-driven chemotaxis. This study shows the interaction of repeat-domain of Tau (TauRD) with the microglial P2Y12 receptor and the corresponding residues for interaction have been analyzed by various in-silico approaches. In the cellular studies, TauRD was found to interact with microglial P2Y12R and induces its cellular expression confirmed by co-immunoprecipitation and western blot analysis. Furthermore, the P2Y12R-mediated TauRD internalization has demonstrated activation of microglia with an increase in the Iba1 level, and TauRD becomes accumulated at the peri-nuclear region for the degradation.
Collapse
Affiliation(s)
- Subashchandrabose Chinnathambi
- Department of Neurochemistry, National Institute of Mental Health and Neuro Sciences (NIMHANS), Institute of National Importance, Bangalore, Karnataka, India.
| | - Hariharakrishnan Chidambaram
- Department of Neurochemistry, National Institute of Mental Health and Neuro Sciences (NIMHANS), Institute of National Importance, Bangalore, Karnataka, India
| |
Collapse
|
3
|
Vithani N, Todd TD, Singh S, Trent T, Blumer KJ, Bowman GR. G Protein Activation Occurs via a Largely Universal Mechanism. J Phys Chem B 2024; 128:3554-3562. [PMID: 38580321 PMCID: PMC11034501 DOI: 10.1021/acs.jpcb.3c07028] [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: 10/23/2023] [Revised: 02/06/2024] [Accepted: 02/08/2024] [Indexed: 04/07/2024]
Abstract
Understanding how signaling proteins like G proteins are allosterically activated is a long-standing challenge with significant biological and medical implications. Because it is difficult to directly observe such dynamic processes, much of our understanding is based on inferences from a limited number of static snapshots of relevant protein structures, mutagenesis data, and patterns of sequence conservation. Here, we use computer simulations to directly interrogate allosteric coupling in six G protein α-subunit isoforms covering all four G protein families. To analyze this data, we introduce automated methods for inferring allosteric networks from simulation data and assessing how allostery is conserved or diverged among related protein isoforms. We find that the allosteric networks in these six G protein α subunits are largely conserved and consist of two pathways, which we call pathway-I and pathway-II. This analysis predicts that pathway-I is generally dominant over pathway-II, which we experimentally corroborate by showing that mutations to pathway-I perturb nucleotide exchange more than mutations to pathway-II. In the future, insights into unique elements of each G protein family could inform the design of isoform-specific drugs. More broadly, our tools should also be useful for studying allostery in other proteins and assessing the extent to which this allostery is conserved in related proteins.
Collapse
Affiliation(s)
- Neha Vithani
- Department
of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, Missouri 63110, United States
- Center
for the Science and Engineering of Living Systems (CSELS), Washington University in St. Louis, St. Louis, Missouri 63130, United States
| | - Tyson D. Todd
- Department
of Cell Biology and Physiology, Washington
University School of Medicine, St. Louis, Missouri 63110, United States
| | - Sukrit Singh
- Department
of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, Missouri 63110, United States
- Center
for the Science and Engineering of Living Systems (CSELS), Washington University in St. Louis, St. Louis, Missouri 63130, United States
| | - Tony Trent
- Departments
of Biochemistry & Biophysics and Bioengineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
| | - Kendall J. Blumer
- Department
of Cell Biology and Physiology, Washington
University School of Medicine, St. Louis, Missouri 63110, United States
| | - Gregory R. Bowman
- Department
of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, Missouri 63110, United States
- Center
for the Science and Engineering of Living Systems (CSELS), Washington University in St. Louis, St. Louis, Missouri 63130, United States
- Departments
of Biochemistry & Biophysics and Bioengineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
| |
Collapse
|
4
|
Yen YC, Li Y, Chen CL, Klose T, Watts VJ, Dessauer CW, Tesmer JJG. Structure of adenylyl cyclase 5 in complex with Gβγ offers insights into ADCY5-related dyskinesia. Nat Struct Mol Biol 2024:10.1038/s41594-024-01263-0. [PMID: 38589608 DOI: 10.1038/s41594-024-01263-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2023] [Accepted: 03/04/2024] [Indexed: 04/10/2024]
Abstract
The nine different membrane-anchored adenylyl cyclase isoforms (AC1-9) in mammals are stimulated by the heterotrimeric G protein, Gαs, but their response to Gβγ regulation is isoform specific. In the present study, we report cryo-electron microscope structures of ligand-free AC5 in complex with Gβγ and a dimeric form of AC5 that could be involved in its regulation. Gβγ binds to a coiled-coil domain that links the AC transmembrane region to its catalytic core as well as to a region (C1b) that is known to be a hub for isoform-specific regulation. We confirmed the Gβγ interaction with both purified proteins and cell-based assays. Gain-of-function mutations in AC5 associated with human familial dyskinesia are located at the interface of AC5 with Gβγ and show reduced conditional activation by Gβγ, emphasizing the importance of the observed interaction for motor function in humans. We propose a molecular mechanism wherein Gβγ either prevents dimerization of AC5 or allosterically modulates the coiled-coil domain, and hence the catalytic core. As our mechanistic understanding of how individual AC isoforms are uniquely regulated is limited, studies such as this may provide new avenues for isoform-specific drug development.
Collapse
Affiliation(s)
- Yu-Chen Yen
- Department of Biological Sciences, Purdue University, West Lafayette, IN, USA
| | - Yong Li
- Department of Integrative Biology and Pharmacology, McGovern Medical School, University of Texas Health Science Center, Houston, TX, USA
| | - Chun-Liang Chen
- Department of Biological Sciences, Purdue University, West Lafayette, IN, USA
| | - Thomas Klose
- Purdue Cryo-EM Facility, Hockmeyer Hall for Structural Biology, Purdue University, West Lafayette, IN, USA
| | - Val J Watts
- Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, West Lafayette, IN, USA
| | - Carmen W Dessauer
- Department of Integrative Biology and Pharmacology, McGovern Medical School, University of Texas Health Science Center, Houston, TX, USA
| | - John J G Tesmer
- Department of Biological Sciences, Purdue University, West Lafayette, IN, USA.
- Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, West Lafayette, IN, USA.
| |
Collapse
|
5
|
Hashimoto T, Suenaga H, Amagai K, Hashimoto J, Kozone I, Takahashi S, Shin-Ya K. In Vitro Module Editing Of NRPS Enables Production Of Highly Potent G q -Signaling Inhibitor FR900359 Derived From Unculturable Plant Symbiont. Angew Chem Int Ed Engl 2024; 63:e202317805. [PMID: 38238265 DOI: 10.1002/anie.202317805] [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: 11/22/2023] [Indexed: 02/03/2024]
Abstract
Heterotrimeric G proteins are key mediators in the signaling of G protein-coupled receptors (GPCR) that are involved in a plethora of important physiological processes and thus major targets of pharmaceutical drugs. The cyclic depsipeptides YM-254890 and FR900359 are strong and selective inhibitors of the Gq subfamily of G proteins. FR900359 was first reported to be produced by unculturable plant symbiont, however, a culturable FR900359 producer was discovered recently by the standard strategy, screening of the producing strain from the environment. As another strategy, we introduce herein the different way to supply natural compounds of unculturable microorganism origin. We therefore embarked on constructing an artificial biosynthetic gene cluster (BGC) for FR900359 with YM-254890 BGC as a template using "in vitro module editing" technology, first developed for the modification of type-I PKS BGCs, to edit YM-254890 BGC. The resulting artificial BGCs coding FR900359 were heterologously expressed in the Pseudomonas putida KT2440 host strain.
Collapse
Affiliation(s)
- Takuya Hashimoto
- National Institute of Advanced Industrial Science and Technology, 2-4-7 Aomi, Koto-ku, Tokyo, 135-0064, Japan
- National Institute of Advanced Industrial Science and Technology, 1-1-1 Higashi, Tsukuba, Ibaraki, 305-8566, Japan
| | - Hikaru Suenaga
- National Institute of Advanced Industrial Science and Technology, 2-4-7 Aomi, Koto-ku, Tokyo, 135-0064, Japan
| | - Keita Amagai
- Natural Product Biosynthesis Research Unit, RIKEN Center for Sustainable Resource Science, 2-1 Hirosawa, Wako, Saitama, 351-0198, Japan
| | - Junko Hashimoto
- Japan Biological Informatics Consortium, 2-4-7 Aomi, Koto-ku, Tokyo, 135-0064, Japan
| | - Ikuko Kozone
- Japan Biological Informatics Consortium, 2-4-7 Aomi, Koto-ku, Tokyo, 135-0064, Japan
| | - Shunji Takahashi
- Natural Product Biosynthesis Research Unit, RIKEN Center for Sustainable Resource Science, 2-1 Hirosawa, Wako, Saitama, 351-0198, Japan
| | - Kazuo Shin-Ya
- National Institute of Advanced Industrial Science and Technology, 2-4-7 Aomi, Koto-ku, Tokyo, 135-0064, Japan
| |
Collapse
|
6
|
Solis GP, Larasati YA, Thiel M, Koval A, Koy A, Katanaev VL. GNAO1 Mutations Affecting the N-Terminal α-Helix of Gαo Lead to Parkinsonism. Mov Disord 2024; 39:601-606. [PMID: 38358016 DOI: 10.1002/mds.29720] [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: 09/25/2023] [Revised: 12/07/2023] [Accepted: 01/02/2024] [Indexed: 02/16/2024] Open
Abstract
BACKGROUND Patients carrying pathogenic variants in GNAO1 present a phenotypic spectrum ranging from severe early-onset epileptic encephalopathy and developmental delay to mild adolescent/adult-onset dystonia. Genotype-phenotype correlation and molecular mechanisms underlying the disease remain understudied. METHODS We analyzed the clinical course of a child carrying the novel GNAO1 mutation c.38T>C;p.Leu13Pro, and structural, biochemical, and cellular properties of the corresponding mutant Gαo-GNAO1-encoded protein-alongside the related mutation c.68T>C;p.Leu23Pro. RESULTS The main clinical feature was parkinsonism with bradykinesia and rigidity, unlike the hyperkinetic movement disorder commonly associated with GNAO1 mutations. The Leu ➔ Pro substitutions have no impact on enzymatic activity or overall folding of Gαo but uniquely destabilize the N-terminal α-helix, blocking formation of the heterotrimeric G-protein and disabling activation by G-protein-coupled receptors. CONCLUSIONS Our study defines a parkinsonism phenotype within the spectrum of GNAO1 disorders and suggests a genotype-phenotype correlation by GNAO1 mutations targeting the N-terminal α-helix of Gαo. © 2024 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.
Collapse
Affiliation(s)
- Gonzalo P Solis
- Translational Research Center in Oncohaematology, Department of Cell Physiology and Metabolism, Faculty of Medicine, University of Geneva, Geneva, Switzerland
| | - Yonika A Larasati
- Translational Research Center in Oncohaematology, Department of Cell Physiology and Metabolism, Faculty of Medicine, University of Geneva, Geneva, Switzerland
| | - Moritz Thiel
- Department of Pediatrics, Faculty of Medicine and University Hospital Cologne, University of Cologne, Cologne, Germany
| | - Alexey Koval
- Translational Research Center in Oncohaematology, Department of Cell Physiology and Metabolism, Faculty of Medicine, University of Geneva, Geneva, Switzerland
| | - Anne Koy
- Department of Pediatrics, Faculty of Medicine and University Hospital Cologne, University of Cologne, Cologne, Germany
- Center for Rare Diseases, Department of Pediatrics, Faculty of Medicine and University Hospital Cologne, University of Cologne, Cologne, Germany
| | - Vladimir L Katanaev
- Translational Research Center in Oncohaematology, Department of Cell Physiology and Metabolism, Faculty of Medicine, University of Geneva, Geneva, Switzerland
- School of Medicine and Life Sciences, Department of Pharmacy and Pharmacology, Far Eastern Federal University, Vladivostok, Russia
| |
Collapse
|
7
|
Isaioglou I, Podia V, Velentzas AD, Kapolas G, Beris D, Karampelias M, Plitsi PK, Chatzopoulos D, Samakovli D, Roussis A, Merzaban J, Milioni D, Stravopodis DJ, Haralampidis K. APRF1 Interactome Reveals HSP90 as a New Player in the Complex That Epigenetically Regulates Flowering Time in Arabidopsis thaliana. Int J Mol Sci 2024; 25:1313. [PMID: 38279311 PMCID: PMC10816710 DOI: 10.3390/ijms25021313] [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: 12/29/2023] [Revised: 01/18/2024] [Accepted: 01/19/2024] [Indexed: 01/28/2024] Open
Abstract
WD40 repeat proteins (WDRs) are present in all eukaryotes and include members that are implicated in numerous cellular activities. They act as scaffold proteins and thus as molecular "hubs" for protein-protein interactions, which mediate the assembly of multifunctional complexes that regulate key developmental processes in Arabidopsis thaliana, such as flowering time, hormonal signaling, and stress responses. Despite their importance, many aspects of their putative functions have not been elucidated yet. Here, we show that the late-flowering phenotype of the anthesis promoting factor 1 (aprf1) mutants is temperature-dependent and can be suppressed when plants are grown under mild heat stress conditions. To gain further insight into the mechanism of APRF1 function, we employed a co-immunoprecipitation (Co-IP) approach to identify its interaction partners. We provide the first interactome of APRF1, which includes proteins that are localized in several subcellular compartments and are implicated in diverse cellular functions. The dual nucleocytoplasmic localization of ARRF1, which was validated through the interaction of APRF1 with HEAT SHOCK PROTEIN 1 (HSP90.1) in the nucleus and with HSP90.2 in the cytoplasm, indicates a dynamic and versatile involvement of APRF1 in multiple biological processes. The specific interaction of APRF1 with the chaperon HSP90.1 in the nucleus expands our knowledge regarding the epigenetic regulation of flowering time in A. thaliana and further suggests the existence of a delicate thermoregulated mechanism during anthesis.
Collapse
Affiliation(s)
- Ioannis Isaioglou
- Section of Botany, Biology Department, National and Kapodistrian University of Athens, 15772 Athens, Greece; (I.I.); (V.P.); (G.K.); (D.B.); (D.S.); (A.R.)
- Bioscience Program, Biological and Environmental Science and Engineering Division, King Abdullah University of Science and Technology (KAUST), Thuwal 23955, Saudi Arabia; (M.K.); (J.M.)
| | - Varvara Podia
- Section of Botany, Biology Department, National and Kapodistrian University of Athens, 15772 Athens, Greece; (I.I.); (V.P.); (G.K.); (D.B.); (D.S.); (A.R.)
| | - Athanassios D. Velentzas
- Section of Cell Biology & Biophysics, Biology Department, National and Kapodistrian University of Athens, 15772 Athens, Greece; (A.D.V.); (D.C.); (D.J.S.)
| | - Georgios Kapolas
- Section of Botany, Biology Department, National and Kapodistrian University of Athens, 15772 Athens, Greece; (I.I.); (V.P.); (G.K.); (D.B.); (D.S.); (A.R.)
| | - Despoina Beris
- Section of Botany, Biology Department, National and Kapodistrian University of Athens, 15772 Athens, Greece; (I.I.); (V.P.); (G.K.); (D.B.); (D.S.); (A.R.)
| | - Michael Karampelias
- Bioscience Program, Biological and Environmental Science and Engineering Division, King Abdullah University of Science and Technology (KAUST), Thuwal 23955, Saudi Arabia; (M.K.); (J.M.)
| | - Panagiota Konstantinia Plitsi
- Department of Agricultural Biotechnology, Agricultural University of Athens, Iera Odos 75, 11855 Athens, Greece (D.M.)
| | - Dimitris Chatzopoulos
- Section of Cell Biology & Biophysics, Biology Department, National and Kapodistrian University of Athens, 15772 Athens, Greece; (A.D.V.); (D.C.); (D.J.S.)
| | - Despina Samakovli
- Section of Botany, Biology Department, National and Kapodistrian University of Athens, 15772 Athens, Greece; (I.I.); (V.P.); (G.K.); (D.B.); (D.S.); (A.R.)
- Department of Agricultural Biotechnology, Agricultural University of Athens, Iera Odos 75, 11855 Athens, Greece (D.M.)
| | - Andreas Roussis
- Section of Botany, Biology Department, National and Kapodistrian University of Athens, 15772 Athens, Greece; (I.I.); (V.P.); (G.K.); (D.B.); (D.S.); (A.R.)
| | - Jasmeen Merzaban
- Bioscience Program, Biological and Environmental Science and Engineering Division, King Abdullah University of Science and Technology (KAUST), Thuwal 23955, Saudi Arabia; (M.K.); (J.M.)
| | - Dimitra Milioni
- Department of Agricultural Biotechnology, Agricultural University of Athens, Iera Odos 75, 11855 Athens, Greece (D.M.)
| | - Dimitrios J. Stravopodis
- Section of Cell Biology & Biophysics, Biology Department, National and Kapodistrian University of Athens, 15772 Athens, Greece; (A.D.V.); (D.C.); (D.J.S.)
| | - Kosmas Haralampidis
- Section of Botany, Biology Department, National and Kapodistrian University of Athens, 15772 Athens, Greece; (I.I.); (V.P.); (G.K.); (D.B.); (D.S.); (A.R.)
| |
Collapse
|
8
|
Gupta PK, Singh A, Rana S. Conformational variants of the ternary complex of C5a, C5aR1, and G-protein. J Biomol Struct Dyn 2024:1-16. [PMID: 38247266 DOI: 10.1080/07391102.2024.2305698] [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: 09/09/2023] [Accepted: 01/09/2024] [Indexed: 01/23/2024]
Abstract
The complement component fragment 5a (C5a) binds and activates two complement receptors like C5aR1 and C5aR2, which play a significant role in orchestrating the proinflammatory function of C5a in tissues through the recruitment of heterotrimeric G-proteins and β-arrestins. Dysregulation of the complement induces excessive production of C5a, which triggers aberrant activation of the C5a-C5aR1-G-protein and C5a-C5aR2-β-arrestin signalling axes in tissues, contributing to the pathology of numerous immune-inflammatory diseases. Thus, understanding the interaction of C5a with C5aR1 and C5aR2, as well as the interaction of G-protein and β-arrestins, respectively, with C5a-C5aR1 and C5a-C5aR2, holds tremendous therapeutic value. In the absence of structural data, we have previously elaborated the binary complexes of C5a-C5aR1 and C5a-C5aR2, as well as the ternary complex of C5a-C5aR2-β-arrestin1, in highly refined model structures. While our ternary model complex of C5a-C5aR1-G-protein was in progress, two cryo-electron microscopy-based ternary structural complexes of C5aR1 were made available by others. However, it is observed that the interaction of the crucial NT-peptide of C5aR1 with C5a, including the portion of the G⍺i-subunit that harbors the switch-I region, is not fully resolved in both complexes. The current study addresses the issues and provides two highly refined alternative model ternary complexes of C5a-C5aR1-G-protein. The study highlights the conformational heterogeneity in C5aR1 by comparing the two conformational variants of the model ternary complex in the context of C5a-C5aR2-β-arrestin1 for further devising methods and molecules targeting both surface and intracellular C5aR1/C5aR2 for effectively mitigating the proinflammatory role of C5a in various disease settings.Communicated by Ramaswamy H. Sarma.
Collapse
Affiliation(s)
- Pulkit Kr Gupta
- Chemical Biology Laboratory, School of Basic Sciences, Indian Institute of Technology Bhubaneswar, Odisha, India
| | - Aditi Singh
- Chemical Biology Laboratory, School of Basic Sciences, Indian Institute of Technology Bhubaneswar, Odisha, India
| | - Soumendra Rana
- Chemical Biology Laboratory, School of Basic Sciences, Indian Institute of Technology Bhubaneswar, Odisha, India
| |
Collapse
|
9
|
Wang S, Sass MI, Kwon Y, Ludlam WG, Smith TM, Carter EJ, Gladden NE, Riggi M, Iwasa JH, Willardson BM, Shen PS. Visualizing the chaperone-mediated folding trajectory of the G protein β5 β-propeller. Mol Cell 2023; 83:3852-3868.e6. [PMID: 37852256 PMCID: PMC10841713 DOI: 10.1016/j.molcel.2023.09.032] [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: 05/17/2023] [Revised: 08/24/2023] [Accepted: 09/26/2023] [Indexed: 10/20/2023]
Abstract
The Chaperonin Containing Tailless polypeptide 1 (CCT) complex is an essential protein folding machine with a diverse clientele of substrates, including many proteins with β-propeller domains. Here, we determine the structures of human CCT in complex with its accessory co-chaperone, phosducin-like protein 1 (PhLP1), in the process of folding Gβ5, a component of Regulator of G protein Signaling (RGS) complexes. Cryoelectron microscopy (cryo-EM) and image processing reveal an ensemble of distinct snapshots that represent the folding trajectory of Gβ5 from an unfolded molten globule to a fully folded β-propeller. These structures reveal the mechanism by which CCT directs Gβ5 folding through initiating specific intermolecular contacts that facilitate the sequential folding of individual β sheets until the propeller closes into its native structure. This work directly visualizes chaperone-mediated protein folding and establishes that CCT orchestrates folding by stabilizing intermediates through interactions with surface residues that permit the hydrophobic core to coalesce into its folded state.
Collapse
Affiliation(s)
- Shuxin Wang
- Department of Biochemistry, School of Medicine, University of Utah, 15 N. Medical Drive East, Salt Lake City, UT 84112, USA
| | - Mikaila I Sass
- Department of Chemistry and Biochemistry, Brigham Young University, C100 BNSN, Provo, UT 84602, USA
| | - Yujin Kwon
- Department of Chemistry and Biochemistry, Brigham Young University, C100 BNSN, Provo, UT 84602, USA
| | - W Grant Ludlam
- Department of Chemistry and Biochemistry, Brigham Young University, C100 BNSN, Provo, UT 84602, USA
| | - Theresa M Smith
- Department of Chemistry and Biochemistry, Brigham Young University, C100 BNSN, Provo, UT 84602, USA
| | - Ethan J Carter
- Department of Chemistry and Biochemistry, Brigham Young University, C100 BNSN, Provo, UT 84602, USA
| | - Nathan E Gladden
- Department of Chemistry and Biochemistry, Brigham Young University, C100 BNSN, Provo, UT 84602, USA
| | - Margot Riggi
- Department of Biochemistry, School of Medicine, University of Utah, 15 N. Medical Drive East, Salt Lake City, UT 84112, USA
| | - Janet H Iwasa
- Department of Biochemistry, School of Medicine, University of Utah, 15 N. Medical Drive East, Salt Lake City, UT 84112, USA
| | - Barry M Willardson
- Department of Chemistry and Biochemistry, Brigham Young University, C100 BNSN, Provo, UT 84602, USA.
| | - Peter S Shen
- Department of Biochemistry, School of Medicine, University of Utah, 15 N. Medical Drive East, Salt Lake City, UT 84112, USA.
| |
Collapse
|
10
|
Rysiewicz B, Błasiak E, Mystek P, Dziedzicka-Wasylewska M, Polit A. Beyond the G protein α subunit: investigating the functional impact of other components of the Gαi 3 heterotrimers. Cell Commun Signal 2023; 21:279. [PMID: 37817242 PMCID: PMC10566112 DOI: 10.1186/s12964-023-01307-w] [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: 06/16/2023] [Accepted: 09/05/2023] [Indexed: 10/12/2023] Open
Abstract
BACKGROUND Specific interactions between G protein-coupled receptors (GPCRs) and G proteins play a key role in mediating signaling events. While there is little doubt regarding receptor preference for Gα subunits, the preferences for specific Gβ and Gγ subunits and the effects of different Gβγ dimer compositions on GPCR signaling are poorly understood. In this study, we aimed to investigate the subcellular localization and functional response of Gαi3-based heterotrimers with different combinations of Gβ and Gγ subunits. METHODS Live-cell imaging microscopy and colocalization analysis were used to investigate the subcellular localization of Gαi3 in combination with Gβ1 or Gβ2 heterotrimers, along with representative Gγ subunits. Furthermore, fluorescence lifetime imaging microscopy (FLIM-FRET) was used to investigate the nanoscale distribution of Gαi3-based heterotrimers in the plasma membrane, specifically with the dopamine D2 receptor (D2R). In addition, the functional response of the system was assessed by monitoring intracellular cAMP levels and conducting bioinformatics analysis to further characterize the heterotrimer complexes. RESULTS Our results show that Gαi3 heterotrimers mainly localize to the plasma membrane, although the degree of colocalization is influenced by the accompanying Gβ and Gγ subunits. Heterotrimers containing Gβ2 showed slightly lower membrane localization compared to those containing Gβ1, but certain combinations, such as Gαi3β2γ8 and Gαi3β2γ10, deviated from this trend. Examination of the spatial arrangement of Gαi3 in relation to D2R and of changes in intracellular cAMP level showed that the strongest functional response is observed for those trimers for which the distance between the receptor and the Gα subunit is smallest, i.e. complexes containing Gβ1 and Gγ8 or Gγ10 subunit. Deprivation of Gαi3 lipid modifications resulted in a significant decrease in the amount of protein present in the cell membrane, but did not always affect intracellular cAMP levels. CONCLUSION Our studies show that the composition of G protein heterotrimers has a significant impact on the strength and specificity of GPCR-mediated signaling. Different heterotrimers may exhibit different conformations, which further affects the interactions of heterotrimers and GPCRs, as well as their interactions with membrane lipids. This study contributes to the understanding of the complex signaling mechanisms underlying GPCR-G-protein interactions and highlights the importance of the diversity of Gβ and Gγ subunits in G-protein signaling pathways. Video Abstract.
Collapse
Affiliation(s)
- Beata Rysiewicz
- Department of Physical Biochemistry, Faculty of Biochemistry Biophysics and Biotechnology, Jagiellonian University, Gronostajowa 7, 30-387, Kraków, Poland
| | - Ewa Błasiak
- Department of Physical Biochemistry, Faculty of Biochemistry Biophysics and Biotechnology, Jagiellonian University, Gronostajowa 7, 30-387, Kraków, Poland
| | - Paweł Mystek
- Department of Physical Biochemistry, Faculty of Biochemistry Biophysics and Biotechnology, Jagiellonian University, Gronostajowa 7, 30-387, Kraków, Poland
| | - Marta Dziedzicka-Wasylewska
- Department of Physical Biochemistry, Faculty of Biochemistry Biophysics and Biotechnology, Jagiellonian University, Gronostajowa 7, 30-387, Kraków, Poland
| | - Agnieszka Polit
- Department of Physical Biochemistry, Faculty of Biochemistry Biophysics and Biotechnology, Jagiellonian University, Gronostajowa 7, 30-387, Kraków, Poland.
| |
Collapse
|
11
|
Shoeva OY, Mukhanova MA, Zakhrabekova S, Hansson M. Ant13 Encodes Regulatory Factor WD40 Controlling Anthocyanin and Proanthocyanidin Synthesis in Barley ( Hordeum vulgare L.). JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2023; 71:6967-6977. [PMID: 37104658 DOI: 10.1021/acs.jafc.2c09051] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
Flavonoid compounds like anthocyanins and proanthocyanidins are important plant secondary metabolites having wide biological activities for humans. In this study, the molecular function of the Ant13 locus, which is one of the key loci governing flavonoid synthesis in barley, was determined. It was found that Ant13 encodes a WD40-type regulatory protein, which is required for transcriptional activation of a set of structural genes encoding enzymes of flavonoid biosynthesis at the leaf sheath base (colored by anthocyanins) and in grains (which accumulate proanthocyanidins). Besides its role in flavonoid biosynthesis, pleiotropic effects of this gene in plant growth were revealed. The mutants deficient in the Ant13 locus showed similar germination rates but a decreased rate of root and shoot growth and yield-related parameters in comparison to the parental cultivars. This is the seventh Ant locus (among 30) for which molecular functions in flavonoid biosynthesis regulation have been determined.
Collapse
Affiliation(s)
- Olesya Yu Shoeva
- Institute of Cytology and Genetics, Siberian Branch of Russian Academy of Sciences, Lavrentjeva ave. 10, 630090 Novosibirsk, Russia
- Kurchatov Center for Genome Research of the Institute of Cytology and Genetics, Siberian Branch of Russian Academy of Sciences, Lavrentjeva ave. 10, 630090 Novosibirsk, Russia
- Faculty of Natural Sciences, Novosibirsk State University, Pirogova str. 1, 630090 Novosibirsk, Russia
| | - Marina A Mukhanova
- Institute of Cytology and Genetics, Siberian Branch of Russian Academy of Sciences, Lavrentjeva ave. 10, 630090 Novosibirsk, Russia
- Faculty of Natural Sciences, Novosibirsk State University, Pirogova str. 1, 630090 Novosibirsk, Russia
| | | | - Mats Hansson
- Department of Biology, Lund University, Sölvegatan 35B, 22362 Lund, Sweden
| |
Collapse
|
12
|
Wang S, Sass MI, Kwon Y, Ludlam WG, Smith TM, Carter EJ, Gladden NE, Riggi M, Iwasa JH, Willardson BM, Shen PS. Visualizing the chaperone-mediated folding trajectory of the G protein β5 β-propeller. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.05.04.539424. [PMID: 37205387 PMCID: PMC10187262 DOI: 10.1101/2023.05.04.539424] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
The cytosolic Chaperonin Containing Tailless polypeptide 1 (CCT) complex is an essential protein folding machine with a diverse clientele of substrates, including many proteins with β-propeller domains. Here, we determined structures of CCT in complex with its accessory co-chaperone, phosducin-like protein 1 (PhLP1), in the process of folding Gβ5, a component of Regulator of G protein Signaling (RGS) complexes. Cryo-EM and image processing revealed an ensemble of distinct snapshots that represent the folding trajectory of Gβ5 from an unfolded molten globule to a fully folded β-propeller. These structures reveal the mechanism by which CCT directs Gβ5 folding through initiating specific intermolecular contacts that facilitate the sequential folding of individual β-sheets until the propeller closes into its native structure. This work directly visualizes chaperone-mediated protein folding and establishes that CCT directs folding by stabilizing intermediates through interactions with surface residues that permit the hydrophobic core to coalesce into its folded state.
Collapse
Affiliation(s)
- Shuxin Wang
- Department of Biochemistry, 15 N. Medical Drive East, University of Utah, Salt Lake City, UT, 84112, USA
| | - Mikaila I. Sass
- Department of Chemistry and Biochemistry, C100 BNSN, Brigham Young University, Provo, UT, 84602, USA
| | - Yujin Kwon
- Department of Chemistry and Biochemistry, C100 BNSN, Brigham Young University, Provo, UT, 84602, USA
| | - W. Grant Ludlam
- Department of Chemistry and Biochemistry, C100 BNSN, Brigham Young University, Provo, UT, 84602, USA
| | - Theresa M. Smith
- Department of Chemistry and Biochemistry, C100 BNSN, Brigham Young University, Provo, UT, 84602, USA
| | - Ethan J. Carter
- Department of Chemistry and Biochemistry, C100 BNSN, Brigham Young University, Provo, UT, 84602, USA
| | - Nathan E. Gladden
- Department of Chemistry and Biochemistry, C100 BNSN, Brigham Young University, Provo, UT, 84602, USA
| | - Margot Riggi
- Department of Biochemistry, 15 N. Medical Drive East, University of Utah, Salt Lake City, UT, 84112, USA
| | - Janet H. Iwasa
- Department of Biochemistry, 15 N. Medical Drive East, University of Utah, Salt Lake City, UT, 84112, USA
| | - Barry M. Willardson
- Department of Chemistry and Biochemistry, C100 BNSN, Brigham Young University, Provo, UT, 84602, USA
| | - Peter S. Shen
- Department of Biochemistry, 15 N. Medical Drive East, University of Utah, Salt Lake City, UT, 84112, USA
| |
Collapse
|
13
|
Yen YC, Li Y, Chen CL, Klose T, Watts VJ, Dessauer CW, Tesmer JJG. Isoform Specific Regulation of Adenylyl Cyclase 5 by Gβγ. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.05.02.539090. [PMID: 37205557 PMCID: PMC10187219 DOI: 10.1101/2023.05.02.539090] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
The nine different membrane-anchored adenylyl cyclase isoforms (AC1-9) in mammals are stimulated by the heterotrimeric G protein Gαs, but their response to Gβγ regulation is isoform-specific. For example, AC5 is conditionally activated by Gβγ. Here, we report cryo-EM structures of ligand-free AC5 in complex with Gβγ and of a dimeric form of AC5 that could be involved in its regulation. Gβγ binds to a coiled-coil domain that links the AC transmembrane region to its catalytic core as well as to a region (C1b) that is known to be a hub for isoform-specific regulation. We confirmed the Gβγ interaction with both purified proteins and cell-based assays. The interface with Gβγ involves AC5 residues that are subject to gain-of-function mutations in humans with familial dyskinesia, indicating that the observed interaction is important for motor function. A molecular mechanism wherein Gβγ either prevents dimerization of AC5 or allosterically modulates the coiled-coil domain, and hence the catalytic core, is proposed. Because our mechanistic understanding of how individual AC isoforms are uniquely regulated is limited, studies such as this may provide new avenues for isoform-specific drug development.
Collapse
Affiliation(s)
- Yu-Chen Yen
- Department of Biological Sciences, Purdue University, West Lafayette, IN, USA
| | - Yong Li
- Department Integrative Biology and Pharmacology, McGovern Medical School, University of Texas Health Science Center, Houston, TX, USA
| | - Chun-Liang Chen
- Department of Biological Sciences, Purdue University, West Lafayette, IN, USA
| | - Thomas Klose
- Purdue CryoEM Facility, Suite 171, Hockmeyer Hall for Structural Biology, Purdue University, West Lafayette, IN, USA
| | - Val J Watts
- Department of Molecular Pharmacology and Medicinal Chemistry, Purdue University, West Lafayette, IN, USA
| | - Carmen W Dessauer
- Department Integrative Biology and Pharmacology, McGovern Medical School, University of Texas Health Science Center, Houston, TX, USA
| | - John J. G. Tesmer
- Department of Biological Sciences, Purdue University, West Lafayette, IN, USA
- Department of Molecular Pharmacology and Medicinal Chemistry, Purdue University, West Lafayette, IN, USA
| |
Collapse
|
14
|
Iverson TM, Singh PK, Cecchini G. An evolving view of Complex II - non-canonical complexes, megacomplexes, respiration, signaling, and beyond. J Biol Chem 2023; 299:104761. [PMID: 37119852 DOI: 10.1016/j.jbc.2023.104761] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2023] [Revised: 04/20/2023] [Accepted: 04/22/2023] [Indexed: 05/01/2023] Open
Abstract
Mitochondrial Complex II is traditionally studied for its participation in two key respiratory processes: the electron transport chain and the Krebs cycle. There is now a rich body of literature explaining how Complex II contributes to respiration. However, more recent research shows that not all of the pathologies associated with altered Complex II activity clearly correlate with this respiratory role. Complex II activity has now been shown to be necessary for a range of biological processes peripherally-related to respiration, including metabolic control, inflammation, and cell fate. Integration of findings from multiple types of studies suggests that Complex II both participates in respiration and controls multiple succinate-dependent signal transduction pathways. Thus, the emerging view is that the true biological function of Complex II is well beyond respiration. This review uses a semi-chronological approach to highlight major paradigm shifts that occurred over time. Special emphasis is given to the more recently identified functions of Complex II and its subunits because these findings have infused new directions into an established field.
Collapse
Affiliation(s)
- T M Iverson
- Departments of Pharmacology, Vanderbilt University, Nashville, TN 37232; Departments of Biochemistry, Vanderbilt University, Nashville, TN 37232; Departments of Center for Structural Biology, Vanderbilt University, Nashville, TN 37232; Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, TN 37232.
| | - Prashant K Singh
- Departments of Pharmacology, Vanderbilt University, Nashville, TN 37232; Departments of Center for Structural Biology, Vanderbilt University, Nashville, TN 37232
| | - Gary Cecchini
- Molecular Biology Division, San Francisco VA Health Care System, San Francisco, CA 94121; Department of Biochemistry & Biophysics, University of California, San Francisco, CA 94158.
| |
Collapse
|
15
|
Hofmann KP, Lamb TD. Rhodopsin, light-sensor of vision. Prog Retin Eye Res 2023; 93:101116. [PMID: 36273969 DOI: 10.1016/j.preteyeres.2022.101116] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2022] [Revised: 08/20/2022] [Accepted: 08/22/2022] [Indexed: 11/06/2022]
Abstract
The light sensor of vertebrate scotopic (low-light) vision, rhodopsin, is a G-protein-coupled receptor comprising a polypeptide chain with bound chromophore, 11-cis-retinal, that exhibits remarkable physicochemical properties. This photopigment is extremely stable in the dark, yet its chromophore isomerises upon photon absorption with 70% efficiency, enabling the activation of its G-protein, transducin, with high efficiency. Rhodopsin's photochemical and biochemical activities occur over very different time-scales: the energy of retinaldehyde's excited state is stored in <1 ps in retinal-protein interactions, but it takes milliseconds for the catalytically active state to form, and many tens of minutes for the resting state to be restored. In this review, we describe the properties of rhodopsin and its role in rod phototransduction. We first introduce rhodopsin's gross structural features, its evolution, and the basic mechanisms of its activation. We then discuss light absorption and spectral sensitivity, photoreceptor electrical responses that result from the activity of individual rhodopsin molecules, and recovery of rhodopsin and the visual system from intense bleaching exposures. We then provide a detailed examination of rhodopsin's molecular structure and function, first in its dark state, and then in the active Meta states that govern its interactions with transducin, rhodopsin kinase and arrestin. While it is clear that rhodopsin's molecular properties are exquisitely honed for phototransduction, from starlight to dawn/dusk intensity levels, our understanding of how its molecular interactions determine the properties of scotopic vision remains incomplete. We describe potential future directions of research, and outline several major problems that remain to be solved.
Collapse
Affiliation(s)
- Klaus Peter Hofmann
- Institut für Medizinische Physik und Biophysik (CC2), Charité, and, Zentrum für Biophysik und Bioinformatik, Humboldt-Unversität zu Berlin, Berlin, 10117, Germany.
| | - Trevor D Lamb
- Eccles Institute of Neuroscience, John Curtin School of Medical Research, The Australian National University, Canberra, ACT 2600, Australia.
| |
Collapse
|
16
|
Structural Basis of the Interaction of the G Proteins, Gαi 1, Gβ 1γ 2 and Gαi 1β 1γ 2, with Membrane Microdomains and Their Relationship to Cell Localization and Activity. Biomedicines 2023; 11:biomedicines11020557. [PMID: 36831093 PMCID: PMC9953545 DOI: 10.3390/biomedicines11020557] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2023] [Revised: 02/01/2023] [Accepted: 02/03/2023] [Indexed: 02/17/2023] Open
Abstract
GPCRs receive signals from diverse messengers and activate G proteins that regulate downstream signaling effectors. Efficient signaling is achieved through the organization of these proteins in membranes. Thus, protein-lipid interactions play a critical role in bringing G proteins together in specific membrane microdomains with signaling partners. Significantly, the molecular basis underlying the membrane distribution of each G protein isoform, fundamental to fully understanding subsequent cell signaling, remains largely unclear. We used model membranes with lipid composition resembling different membrane microdomains, and monomeric, dimeric and trimeric Gi proteins with or without single and multiple mutations to investigate the structural bases of G protein-membrane interactions. We demonstrated that cationic amino acids in the N-terminal region of the Gαi1 and C-terminal region of the Gγ2 subunit, as well as their myristoyl, palmitoyl and geranylgeranyl moieties, define the differential G protein form interactions with membranes containing different lipid classes (PC, PS, PE, SM, Cho) and the various microdomains they may form (Lo, Ld, PC bilayer, charged, etc.). These new findings in part explain the molecular basis underlying amphitropic protein translocation to membranes and localization to different membrane microdomains and the role of these interactions in cell signal propagation, pathophysiology and therapies targeted to lipid membranes.
Collapse
|
17
|
Aumiller JL, Wedegaertner PB. Disruption of the interaction between mutationally activated Gα q and Gβγ attenuates aberrant signaling. J Biol Chem 2023; 299:102880. [PMID: 36626984 PMCID: PMC9926304 DOI: 10.1016/j.jbc.2023.102880] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2022] [Revised: 12/14/2022] [Accepted: 12/31/2022] [Indexed: 01/09/2023] Open
Abstract
Heterotrimeric G protein stimulation via G protein-coupled receptors promotes downstream proliferative signaling. Mutations can occur in Gα proteins which prevent GTP hydrolysis; this allows the G proteins to signal independently of G protein-coupled receptors and can result in various cancers, such as uveal melanoma (UM). Most UM cases harbor Q209L, Q209P, or R183C mutations in Gαq/11 proteins, rendering the proteins constitutively active (CA). Although it is generally thought that active, GTP-bound Gα subunits are dissociated from and signal independently of Gβγ, accumulating evidence indicates that some CA Gα mutants, such as Gαq/11, retain binding to Gβγ, and this interaction is necessary for signaling. Here, we demonstrate that disrupting the interaction between Gβγ and Gαq is sufficient to inhibit aberrant signaling driven by CA Gαq. Introduction of the I25A point mutation in the N-terminal α helical domain of CA Gαq to inhibit Gβγ binding, overexpression of the G protein Gαo to sequester Gβγ, and siRNA depletion of Gβ subunits inhibited or abolished CA Gαq signaling to the MAPK and YAP pathways. Moreover, in HEK 293 cells and in UM cell lines, we show that Gαq-Q209P and Gαq-R183C are more sensitive to the loss of Gβγ interaction than Gαq-Q209L. Our study challenges the idea that CA Gαq/11 signals independently of Gβγ and demonstrates differential sensitivity between the Gαq-Q209L, Gαq-Q209P, and Gαq-R183C mutants.
Collapse
|
18
|
GIRK Channels as Candidate Targets for the Treatment of Substance Use Disorders. Biomedicines 2022; 10:biomedicines10102552. [PMID: 36289814 PMCID: PMC9599444 DOI: 10.3390/biomedicines10102552] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2022] [Revised: 10/05/2022] [Accepted: 10/09/2022] [Indexed: 11/16/2022] Open
Abstract
Substance use disorders (SUDs) are chronic, lifelong disorders that have serious consequences. Repeated substance use alters brain function. G-protein-activated inwardly rectifying potassium (GIRK) channels are expressed widely in the brain, including the reward system, and regulate neuronal excitability. Functional GIRK channels are identified as heterotetramers of GIRK subunits (GIRK1–4). The GIRK1, GIRK2, and GIRK3 subunits are mainly expressed in rodent brain regions, and various addictive substances act on the brain through GIRK channels. Studies with animals (knockout and missense mutation animals) and humans have demonstrated the involvement of GIRK channels in the effects of addictive substances. Additionally, GIRK channel blockers affect behavioral responses to addictive substances. Thus, GIRK channels play a key role in SUDs, and GIRK channel modulators may be candidate medications. Ifenprodil is a GIRK channel blocker that does not have serious side effects. Two clinical trials were conducted to investigate the effects of ifenprodil in patients with alcohol or methamphetamine use disorder. Although the number of participants was relatively low, evidence of its safety and efficacy was found. The present review discusses the potential of GIRK channel modulators as possible medications for addiction. Therapeutic agents that target GIRK channels may be promising for the treatment of SUDs.
Collapse
|
19
|
Jiang H, Galtes D, Wang J, Rockman HA. G protein-coupled receptor signaling: transducers and effectors. Am J Physiol Cell Physiol 2022; 323:C731-C748. [PMID: 35816644 PMCID: PMC9448338 DOI: 10.1152/ajpcell.00210.2022] [Citation(s) in RCA: 21] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2022] [Revised: 06/27/2022] [Accepted: 07/10/2022] [Indexed: 01/14/2023]
Abstract
G protein-coupled receptors (GPCRs) are of considerable interest due to their importance in a wide range of physiological functions and in a large number of Food and Drug Administration (FDA)-approved drugs as therapeutic entities. With continued study of their function and mechanism of action, there is a greater understanding of how effector molecules interact with a receptor to initiate downstream effector signaling. This review aims to explore the signaling pathways, dynamic structures, and physiological relevance in the cardiovascular system of the three most important GPCR signaling effectors: heterotrimeric G proteins, GPCR kinases (GRKs), and β-arrestins. We will first summarize their prominent roles in GPCR pharmacology before transitioning into less well-explored areas. As new technologies are developed and applied to studying GPCR structure and their downstream effectors, there is increasing appreciation for the elegance of the regulatory mechanisms that mediate intracellular signaling and function.
Collapse
Affiliation(s)
- Haoran Jiang
- Department of Medicine, Duke University Medical Center, Durham, North Carolina
| | - Daniella Galtes
- Department of Medicine, Duke University Medical Center, Durham, North Carolina
| | - Jialu Wang
- Department of Medicine, Duke University Medical Center, Durham, North Carolina
| | - Howard A Rockman
- Department of Medicine, Duke University Medical Center, Durham, North Carolina
- Department of Cell Biology, Duke University Medical Center, Durham, North Carolina
| |
Collapse
|
20
|
Checkpoints and Immunity in Cancers: Role of GNG12. Pharmacol Res 2022; 180:106242. [DOI: 10.1016/j.phrs.2022.106242] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Revised: 04/25/2022] [Accepted: 04/28/2022] [Indexed: 12/24/2022]
|
21
|
Guo P, Tai Y, Wang M, Sun H, Zhang L, Wei W, Xiang YK, Wang Q. Gα 12 and Gα 13: Versatility in Physiology and Pathology. Front Cell Dev Biol 2022; 10:809425. [PMID: 35237598 PMCID: PMC8883321 DOI: 10.3389/fcell.2022.809425] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2021] [Accepted: 01/17/2022] [Indexed: 01/14/2023] Open
Abstract
G protein-coupled receptors (GPCRs), as the largest family of receptors in the human body, are involved in the pathological mechanisms of many diseases. Heterotrimeric G proteins represent the main molecular switch and receive cell surface signals from activated GPCRs. Growing evidence suggests that Gα12 subfamily (Gα12/13)-mediated signaling plays a crucial role in cellular function and various pathological processes. The current research on the physiological and pathological function of Gα12/13 is constantly expanding, Changes in the expression levels of Gα12/13 have been found in a wide range of human diseases. However, the mechanistic research on Gα12/13 is scattered. This review briefly describes the structural sequences of the Gα12/13 isoforms and introduces the coupling of GPCRs and non-GPCRs to Gα12/13. The effects of Gα12/13 on RhoA and other signaling pathways and their roles in cell proliferation, migration, and immune cell function, are discussed. Finally, we focus on the pathological impacts of Gα12/13 in cancer, inflammation, metabolic diseases, fibrotic diseases, and circulatory disorders are brought to focus.
Collapse
Affiliation(s)
- Paipai Guo
- Key Laboratory of Anti-inflammatory and Immune Medicine, Ministry of Education, Collaborative Innovation Center of Anti-inflammatory and Immune Medicine, Institute of Clinical Pharmacology, Anhui Medical University, Hefei, China
| | - Yu Tai
- Key Laboratory of Anti-inflammatory and Immune Medicine, Ministry of Education, Collaborative Innovation Center of Anti-inflammatory and Immune Medicine, Institute of Clinical Pharmacology, Anhui Medical University, Hefei, China
| | - Manman Wang
- Key Laboratory of Anti-inflammatory and Immune Medicine, Ministry of Education, Collaborative Innovation Center of Anti-inflammatory and Immune Medicine, Institute of Clinical Pharmacology, Anhui Medical University, Hefei, China
| | - Hanfei Sun
- Key Laboratory of Anti-inflammatory and Immune Medicine, Ministry of Education, Collaborative Innovation Center of Anti-inflammatory and Immune Medicine, Institute of Clinical Pharmacology, Anhui Medical University, Hefei, China
| | - Lingling Zhang
- Key Laboratory of Anti-inflammatory and Immune Medicine, Ministry of Education, Collaborative Innovation Center of Anti-inflammatory and Immune Medicine, Institute of Clinical Pharmacology, Anhui Medical University, Hefei, China
| | - Wei Wei
- Key Laboratory of Anti-inflammatory and Immune Medicine, Ministry of Education, Collaborative Innovation Center of Anti-inflammatory and Immune Medicine, Institute of Clinical Pharmacology, Anhui Medical University, Hefei, China
| | - Yang K Xiang
- Department of Pharmacology, University of California, Davis, Davis, CA, United States.,VA Northern California Health Care System, Mather, CA, United States
| | - Qingtong Wang
- Key Laboratory of Anti-inflammatory and Immune Medicine, Ministry of Education, Collaborative Innovation Center of Anti-inflammatory and Immune Medicine, Institute of Clinical Pharmacology, Anhui Medical University, Hefei, China
| |
Collapse
|
22
|
Genome Wide Identification and Characterization of Apple WD40 Proteins and Expression Analysis in Response to ABA, Drought, and Low Temperature. HORTICULTURAE 2022. [DOI: 10.3390/horticulturae8020141] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Basic WD40 proteins, which are characterized by a conserved WD40 domain, comprise a superfamily of regulatory proteins in plants and play important roles in plant growth and development. However, WD40 genes have been rarely studied in apple (Malus × domestica Borkh.). In this study, 346 WD40 genes classified in 12 subfamilies, were identified in the apple genome. Evolutionary analysis of WD40 proteins in apple and Arabidopsis revealed that the genes were classifiable into 14 groups, and the exon/intron structure of each group showed a similar structure. Analysis of collinearity showed that the large-scale amplification of WD40 genes in apple was largely attributable to recent whole-genome replication events. Nineteen candidate stress-related genes, selected by GO annotation and comparison with Arabidopsis homologs, showed different expression profiles in six organs at different developmental stages in response to exogenous abscisic acid (ABA), drought, and low temperature. Eight genes (MdWD40-17, 24, 70, 74, 219, 256, 283, and 307) showed a distinct response to one or more treatments (ABA, drought, and low temperature) as indicated by quantitative real-time PCR analysis. Taken together, these data provide rich resources for further study of MdWD40 genes and their potential roles in stress responses in apple.
Collapse
|
23
|
Fina ME, Wang J, Vedula P, Tang HY, Kashina A, Dong DW. Arginylation Regulates G-protein Signaling in the Retina. Front Cell Dev Biol 2022; 9:807345. [PMID: 35127722 PMCID: PMC8815403 DOI: 10.3389/fcell.2021.807345] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2021] [Accepted: 12/17/2021] [Indexed: 12/03/2022] Open
Abstract
Arginylation is a post-translational modification mediated by the arginyltransferase (Ate1). We recently showed that conditional deletion of Ate1 in the nervous system leads to increased light-evoked response sensitivities of ON-bipolar cells in the retina, indicating that arginylation regulates the G-protein signaling complexes of those neurons and/or photoreceptors. However, none of the key players in the signaling pathway were previously shown to be arginylated. Here we show that Gαt1, Gβ1, RGS6, and RGS7 are arginylated in the retina and RGS6 and RGS7 protein levels are elevated in Ate1 knockout, suggesting that arginylation plays a direct role in regulating their protein level and the G-protein-mediated responses in the retina.
Collapse
Affiliation(s)
- Marie E. Fina
- Department of Biomedical Sciences, School of Veterinary Medicines, University of Pennsylvania, Philadelphia, PA, United States
| | - Junling Wang
- Department of Biomedical Sciences, School of Veterinary Medicines, University of Pennsylvania, Philadelphia, PA, United States
| | - Pavan Vedula
- Department of Biomedical Sciences, School of Veterinary Medicines, University of Pennsylvania, Philadelphia, PA, United States
| | - Hsin-Yao Tang
- Proteomics and Metabolomics Facility, The Wistar Institute, Philadelphia, PA, United States
| | - Anna Kashina
- Department of Biomedical Sciences, School of Veterinary Medicines, University of Pennsylvania, Philadelphia, PA, United States
- *Correspondence: Anna Kashina, ; Dawei W. Dong,
| | - Dawei W. Dong
- Department of Biomedical Sciences, School of Veterinary Medicines, University of Pennsylvania, Philadelphia, PA, United States
- Institute for Biomedical Informatics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States
- *Correspondence: Anna Kashina, ; Dawei W. Dong,
| |
Collapse
|
24
|
A new visual design language for biological structures in a cell. Structure 2022; 30:485-497.e3. [DOI: 10.1016/j.str.2022.01.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2021] [Revised: 09/28/2021] [Accepted: 01/04/2022] [Indexed: 01/16/2023]
|
25
|
Hussain M, Cummins MC, Endo-Streeter S, Sondek J, Kuhlman B. Designer proteins that competitively inhibit Gα q by targeting its effector site. J Biol Chem 2021; 297:101348. [PMID: 34715131 PMCID: PMC8633581 DOI: 10.1016/j.jbc.2021.101348] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2021] [Revised: 10/12/2021] [Accepted: 10/22/2021] [Indexed: 11/30/2022] Open
Abstract
During signal transduction, the G protein, Gαq, binds and activates phospholipase C-β isozymes. Several diseases have been shown to manifest upon constitutively activating mutation of Gαq, such as uveal melanoma. Therefore, methods are needed to directly inhibit Gαq. Previously, we demonstrated that a peptide derived from a helix-turn-helix (HTH) region of PLC-β3 (residues 852-878) binds Gαq with low micromolar affinity and inhibits Gαq by competing with full-length PLC-β isozymes for binding. Since the HTH peptide is unstructured in the absence of Gαq, we hypothesized that embedding the HTH in a folded protein might stabilize the binding-competent conformation and further improve the potency of inhibition. Using the molecular modeling software Rosetta, we searched the Protein Data Bank for proteins with similar HTH structures near their surface. The candidate proteins were computationally docked against Gαq, and their surfaces were redesigned to stabilize this interaction. We then used yeast surface display to affinity mature the designs. The most potent design bound Gαq/i with high affinity in vitro (KD = 18 nM) and inhibited activation of PLC-β isozymes in HEK293 cells. We anticipate that our genetically encoded inhibitor will help interrogate the role of Gαq in healthy and disease model systems. Our work demonstrates that grafting interaction motifs into folded proteins is a powerful approach for generating inhibitors of protein-protein interactions.
Collapse
Affiliation(s)
- Mahmud Hussain
- Department of Biochemistry and Biophysics, University of North Carolina, Chapel Hill, North Carolina, USA
| | - Matthew C Cummins
- Department of Pharmacology, University of North Carolina, Chapel Hill, North Carolina, USA
| | - Stuart Endo-Streeter
- Department of Pharmacology, University of North Carolina, Chapel Hill, North Carolina, USA
| | - John Sondek
- Department of Biochemistry and Biophysics, University of North Carolina, Chapel Hill, North Carolina, USA; Department of Pharmacology, University of North Carolina, Chapel Hill, North Carolina, USA; Lineberger Comprehensive Cancer Center, University of North Carolina, Chapel Hill, North Carolina, USA.
| | - Brian Kuhlman
- Department of Biochemistry and Biophysics, University of North Carolina, Chapel Hill, North Carolina, USA; Lineberger Comprehensive Cancer Center, University of North Carolina, Chapel Hill, North Carolina, USA.
| |
Collapse
|
26
|
Mafi A, Kim SK, Chou KC, Güthrie B, Goddard WA. Predicted Structure of Fully Activated Tas1R3/1R3' Homodimer Bound to G Protein and Natural Sugars: Structural Insights into G Protein Activation by a Class C Sweet Taste Homodimer with Natural Sugars. J Am Chem Soc 2021; 143:16824-16838. [PMID: 34585929 DOI: 10.1021/jacs.1c08839] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The Tas1R3 G protein-coupled receptor constitutes the main component of sweet taste sensory response in humans via forming a heterodimer with Tas1R2 or a homodimer with Tas1R3. The Tas1R3/1R3' homodimer serves as a low-affinity sweet taste receptor, stimulating gustducin G protein (GGust) signaling in the presence of a high concentration of natural sugars. This provides an additional means to detect the taste of natural sugars, thereby differentiating the flavors between natural sugars and artificial sweeteners. We report here the predicted 3D structure of active state Tas1R3/1R3' homodimer complexed with heterotrimeric GGust and sucrose. We discovered that the GGust makes ionic anchors to intracellular loops 1 and 2 of Tas1R3 while the Gα-α5 helix engages the cytoplasmic region extensively through salt bridge and hydrophobic interactions. We show that in the activation of this complex the Venus flytrap domains of the homodimer undergo a remarkable twist up to ∼100° rotation around the vertical axis to adopt a closed-closed conformation while the intracellular region relaxes to an open-open conformation. We find that binding of sucrose to the homodimer stabilizes a preactivated conformation with a largely open intracellular region that recruits and activates the GGust. Upon activation, the Gα subunit spontaneously opens up the nucleotide-binding site, making nucleotide exchange facile for signaling. This activation of GGust promotes the interdomain twist of the Venus flytrap domains. These structures and transformations could potentially be a basis for the design of new sweeteners with higher activity and less unpleasant flavors.
Collapse
Affiliation(s)
- Amirhossein Mafi
- Materials and Process Simulation Center (139-74), California Institute of Technology, Pasadena, California 91125, United States
| | - Soo-Kyung Kim
- Materials and Process Simulation Center (139-74), California Institute of Technology, Pasadena, California 91125, United States
| | - Keng C Chou
- Department of Chemistry, University of British Columbia, Vancouver, BC V6T 1Z1, Canada
| | - Brian Güthrie
- Cargill Global Food Research, Wayzata, Minnesota 55391, United States
| | - William A Goddard
- Materials and Process Simulation Center (139-74), California Institute of Technology, Pasadena, California 91125, United States
| |
Collapse
|
27
|
Novel Binding Partners for CCT and PhLP1 Suggest a Common Folding Mechanism for WD40 Proteins with a 7-Bladed Beta-Propeller Structure. Proteomes 2021; 9:proteomes9040040. [PMID: 34698247 PMCID: PMC8544692 DOI: 10.3390/proteomes9040040] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2021] [Revised: 09/15/2021] [Accepted: 09/27/2021] [Indexed: 11/25/2022] Open
Abstract
This study investigates whether selected WD40 proteins with a 7-bladed β-propeller structure, similar to that of the β subunit of the G protein heterotrimer, interact with the cytosolic chaperonin CCT and its known binding partner, PhLP1. Previous studies have shown that CCT is required for the folding of the Gβ subunit and other WD40 proteins. The role of PhLP1 in the folding of Gβ has also been established, but it is unknown if PhLP1 assists in the folding of other Gβ-like proteins. The binding of three Gβ-like proteins, TBL2, MLST8 and CDC20, to CCT and PhLP1, was demonstrated in this study. Co-immunoprecipitation assays identified one novel binding partner for CCT and three new interactors for PhLP1. All three of the studied proteins interact with CCT and PhLP1, suggesting that these proteins may have a folding machinery in common with that of Gβ and that the well-established Gβ folding mechanism may have significantly broader biological implications than previously thought. These findings contribute to continuous efforts to determine common traits and unique differences in the folding mechanism of the WD40 β-propeller protein family, and the role PhLP1 has in this process.
Collapse
|
28
|
Abstract
Aspergillus fumigatus gives rise to invasive aspergillosis in immunocompromised individuals. The rise of A. fumigatus antifungal resistance threatens a limited arsenal of treatment options. Here, we use genetic and molecular approaches to dissect the contribution of the citron homology (CNH) domain of the guanine nucleotide exchange factor Rom2 in regulating the biosynthesis of the essential and unique fungal cell wall, an important target of antifungal compounds. The CNH domain plays an essential role as a stabilizer for the small GTPase Rho1, a key regulator of glucan biosynthesis. This work provides a model for their interaction, revealing a promising molecular mechanism to explore in the quest for novel antifungal compounds. Aspergillus fumigatus is a human opportunistic pathogen showing emerging resistance against a limited repertoire of antifungal agents available. The GTPase Rho1 has been identified as an important regulator of the cell wall integrity signaling pathway that regulates the composition of the cell wall, a structure that is unique to fungi and serves as a target for antifungal compounds. Rom2, the guanine nucleotide exchange factor to Rho1, contains a C-terminal citron homology (CNH) domain of unknown function that is found in many other eukaryotic genes. Here, we show that the Rom2 CNH domain interacts directly with Rho1 to modulate β-glucan and chitin synthesis. We report the structure of the Rom2 CNH domain, revealing that it adopts a seven-bladed β-propeller fold containing three unusual loops. A model of the Rho1–Rom2 CNH complex suggests that the Rom2 CNH domain interacts with the Rho1 Switch II motif. This work uncovers the role of the Rom2 CNH domain as a scaffold for Rho1 signaling in fungal cell wall biosynthesis.
Collapse
|
29
|
The G protein-first activation mechanism of opioid receptors by Gi protein and agonists. QRB DISCOVERY 2021. [PMID: 37529677 PMCID: PMC10392629 DOI: 10.1017/qrd.2021.7] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
AbstractWe report the G protein-first mechanism for activation of G protein-coupled receptors (GPCR) for the three closest subtypes of the opioid receptors (OR), μOR, κOR and δOR. We find that they couple to the inactive Gi protein-bound guanosine diphosphate (GDP) prior to agonist binding. The inactive Gi protein forms anchors to the intracellular loops of the inactive apo-μOR, apo-κOR and apo-δOR, inducing opening of the cytoplasmic region to form a pre-activated state that holds Gi protein in place until agonist binds. Then, agonist binds to μOR, κOR and δOR already complexed with Gi protein, to trigger the Gαi to open up the tightly coupled GDP binding site, making GDP accessible for GTP exchange, an essential step for Gi signalling. We show that the agonist alone cannot open the intracellular region of μOR and κOR, requiring Gi protein to open the cytoplasmic region by itself. We consider that this G protein-first mechanism may apply to activation of other Class A GPCRs. However, for δOR, agonist binding can open up the intracellular region to encourage Gi protein recruitment. Thus, activation of Gi protein mediated by δOR favourably may proceed with either ligand-first or G protein-first activation mechanisms.
Collapse
|
30
|
Fjær R, Marciniak K, Sundnes O, Hjorthaug H, Sheng Y, Hammarström C, Sitek JC, Vigeland MD, Backe PH, Øye AM, Fosse JH, Stav-Noraas TE, Uchiyama Y, Matsumoto N, Comi A, Pevsner J, Haraldsen G, Selmer KK. A novel somatic mutation in GNB2 provides new insights to the pathogenesis of Sturge-weber syndrome. Hum Mol Genet 2021; 30:1919-1931. [PMID: 34124757 PMCID: PMC8522634 DOI: 10.1093/hmg/ddab144] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2021] [Revised: 05/25/2021] [Accepted: 05/25/2021] [Indexed: 12/30/2022] Open
Abstract
Sturge-Weber syndrome (SWS) is a neurocutaneous disorder characterised by vascular malformations affecting skin, eyes and leptomeninges of the brain, which can lead to glaucoma, seizures and intellectual disability. The discovery of a disease-causing somatic missense mutation in the GNAQ gene, encoding an alpha chain of heterotrimeric G-proteins, has initiated efforts to understand how G-proteins contribute to SWS pathogenesis. The mutation is predominantly detected in endothelial cells and is currently believed to affect downstream MAPK-signalling. In this study of six Norwegian patients with classical SWS, we aimed to identify somatic mutations through deep sequencing of DNA from skin biopsies. Surprisingly, one patient was negative for the GNAQ mutation, but instead harboured a somatic mutation in GNB2 (NM_005273.3:c.232A > G, p.Lys78Glu) which encodes a beta chain of the same G-protein complex. The positions of the mutant amino acids in the G-protein are essential for complex reassembly. Therefore, failure of reassembly and continuous signalling is a likely consequence of both mutations. Ectopic expression of mutant proteins in endothelial cells revealed that expression of either mutant reduced cellular proliferation, yet regulated MAPK-signalling differently, suggesting that dysregulated MAPK-signalling cannot fully explain the SWS phenotype. Instead, both mutants reduced synthesis of YAP, a transcriptional co-activator of the Hippo signalling pathway, suggesting a key role for this pathway in the vascular pathogenesis of SWS. The discovery of the GNB2 mutation sheds novel light on the pathogenesis of SWS and suggests that future research on targets of treatment should be directed towards the YAP, rather than the MAPK, signalling pathway.
Collapse
Affiliation(s)
- Roar Fjær
- Department of Medical Genetics, Oslo University Hospital and University of Oslo, Oslo, Norway.,Department of Neurology and Clinical Neurophysiology, St. Olavs University Hospital, Trondheim.,Institute of Clinical Medicine, University of Oslo, Oslo, Norway
| | - Katarzyna Marciniak
- K.G. Jebsen Inflammation Research Centre, University of Oslo, Oslo, Norway.,Department of Pathology, Oslo University Hospital, Oslo, Norway
| | - Olav Sundnes
- K.G. Jebsen Inflammation Research Centre, University of Oslo, Oslo, Norway.,Department of Pathology, Oslo University Hospital, Oslo, Norway.,Department of Dermatology, Oslo University Hospital, Oslo, Norway
| | - Hanne Hjorthaug
- Department of Medical Genetics, Oslo University Hospital and University of Oslo, Oslo, Norway
| | - Ying Sheng
- Department of Medical Genetics, Oslo University Hospital and University of Oslo, Oslo, Norway
| | - Clara Hammarström
- K.G. Jebsen Inflammation Research Centre, University of Oslo, Oslo, Norway.,Department of Pathology, Oslo University Hospital, Oslo, Norway
| | - Jan Cezary Sitek
- Department of Dermatology, Oslo University Hospital, Oslo, Norway
| | - Magnus Dehli Vigeland
- Department of Medical Genetics, Oslo University Hospital and University of Oslo, Oslo, Norway
| | - Paul Hoff Backe
- Department of Microbiology, Oslo University Hospital, 0424 Oslo, Norway.,Department of Medical Biochemistry, Oslo University Hospital, 0424 Oslo, Norway.,Institute of Clinical Medicine, University of Oslo, Oslo, Norway
| | - Ane-Marte Øye
- Department of Medical Genetics, Oslo University Hospital and University of Oslo, Oslo, Norway
| | - Johanna Hol Fosse
- K.G. Jebsen Inflammation Research Centre, University of Oslo, Oslo, Norway.,Department of Pathology, Oslo University Hospital, Oslo, Norway
| | | | - Yuri Uchiyama
- Department of Human Genetics, Yokohama City University Graduate School of Medicine, Yokohama, Japan.,Department of Rare Disease Genomics, Yokohama City University Hospital, Yokohama, Japan
| | - Naomichi Matsumoto
- Department of Human Genetics, Yokohama City University Graduate School of Medicine, Yokohama, Japan
| | - Anne Comi
- Department of Neurology, Hugo Moser Kennedy Krieger Research Institute, Baltimore, Maryland, USA.,Department of Neurology and Department of Pediatrics, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Jonathan Pevsner
- Department of Neurology, Hugo Moser Kennedy Krieger Research Institute, Baltimore, Maryland, USA.,Department of Psychiatry and Behavioral Sciences, John Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Guttorm Haraldsen
- K.G. Jebsen Inflammation Research Centre, University of Oslo, Oslo, Norway.,Department of Pathology, Oslo University Hospital, Oslo, Norway
| | - Kaja Kristine Selmer
- Department of Medical Genetics, Oslo University Hospital and University of Oslo, Oslo, Norway.,National Centre for Rare Epilepsy-Related Disorders, Oslo University Hospital and the University of Oslo, Oslo, Norway.,Department of Research and Innovation, Division of Clinical Neuroscience, Oslo University Hospital, Oslo, Norway
| |
Collapse
|
31
|
Nubbemeyer B, Pepanian A, Paul George AA, Imhof D. Strategies towards Targeting Gαi/s Proteins: Scanning of Protein-Protein Interaction Sites To Overcome Inaccessibility. ChemMedChem 2021; 16:1696-1715. [PMID: 33615736 PMCID: PMC8252600 DOI: 10.1002/cmdc.202100039] [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: 01/15/2021] [Indexed: 12/16/2022]
Abstract
Heterotrimeric G proteins are classified into four subfamilies and play a key role in signal transduction. They transmit extracellular signals to intracellular effectors subsequent to the activation of G protein-coupled receptors (GPCRs), which are targeted by over 30 % of FDA-approved drugs. However, addressing G proteins as drug targets represents a compelling alternative, for example, when G proteins act independently of the corresponding GPCRs, or in cases of complex multifunctional diseases, when a large number of different GPCRs are involved. In contrast to Gαq, efforts to target Gαi/s by suitable chemical compounds has not been successful so far. Here, a comprehensive analysis was conducted examining the most important interface regions of Gαi/s with its upstream and downstream interaction partners. By assigning the existing compounds and the performed approaches to the respective interfaces, the druggability of the individual interfaces was ranked to provide perspectives for selective targeting of Gαi/s in the future.
Collapse
Affiliation(s)
- Britta Nubbemeyer
- Pharmaceutical Biochemistry and BioanalyticsPharmaceutical InstituteUniversity of BonnAn der Immenburg 453121BonnGermany
| | - Anna Pepanian
- Pharmaceutical Biochemistry and BioanalyticsPharmaceutical InstituteUniversity of BonnAn der Immenburg 453121BonnGermany
| | | | - Diana Imhof
- Pharmaceutical Biochemistry and BioanalyticsPharmaceutical InstituteUniversity of BonnAn der Immenburg 453121BonnGermany
| |
Collapse
|
32
|
Tennakoon M, Senarath K, Kankanamge D, Ratnayake K, Wijayaratna D, Olupothage K, Ubeysinghe S, Martins-Cannavino K, Hébert TE, Karunarathne A. Subtype-dependent regulation of Gβγ signalling. Cell Signal 2021; 82:109947. [PMID: 33582184 PMCID: PMC8026654 DOI: 10.1016/j.cellsig.2021.109947] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2020] [Revised: 02/01/2021] [Accepted: 02/02/2021] [Indexed: 01/04/2023]
Abstract
G protein-coupled receptors (GPCRs) transmit information to the cell interior by transducing external signals to heterotrimeric G protein subunits, Gα and Gβγ subunits, localized on the inner leaflet of the plasma membrane. Though the initial focus was mainly on Gα-mediated events, Gβγ subunits were later identified as major contributors to GPCR-G protein signalling. A broad functional array of Gβγ signalling has recently been attributed to Gβ and Gγ subtype diversity, comprising 5 Gβ and 12 Gγ subtypes, respectively. In addition to displaying selectivity towards each other to form the Gβγ dimer, numerous studies have identified preferences of distinct Gβγ combinations for specific GPCRs, Gα subtypes and effector molecules. Importantly, Gβ and Gγ subtype-dependent regulation of downstream effectors, representing a diverse range of signalling pathways and physiological functions have been found. Here, we review the literature on the repercussions of Gβ and Gγ subtype diversity on direct and indirect regulation of GPCR/G protein signalling events and their physiological outcomes. Our discussion additionally provides perspective in understanding the intricacies underlying molecular regulation of subtype-specific roles of Gβγ signalling and associated diseases.
Collapse
Affiliation(s)
- Mithila Tennakoon
- Department of Chemistry and Biochemistry, The University of Toledo, Toledo, OH 43606, USA
| | - Kanishka Senarath
- Genetics and Molecular Biology Unit, University of Sri Jayewardenepura, Nugegoda, Sri Lanka
| | - Dinesh Kankanamge
- Department of Chemistry and Biochemistry, The University of Toledo, Toledo, OH 43606, USA
| | - Kasun Ratnayake
- Department of Chemistry and Biochemistry, The University of Toledo, Toledo, OH 43606, USA; Department of Pharmacology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Dhanushan Wijayaratna
- Department of Chemistry and Biochemistry, The University of Toledo, Toledo, OH 43606, USA
| | - Koshala Olupothage
- Department of Chemistry and Biochemistry, The University of Toledo, Toledo, OH 43606, USA
| | - Sithurandi Ubeysinghe
- Department of Chemistry and Biochemistry, The University of Toledo, Toledo, OH 43606, USA
| | | | - Terence E Hébert
- Department of Pharmacology and Therapeutics, McGill University, Montréal, QC H3G 1Y6, Canada.
| | - Ajith Karunarathne
- Department of Chemistry and Biochemistry, The University of Toledo, Toledo, OH 43606, USA.
| |
Collapse
|
33
|
Photoreceptor phosphodiesterase (PDE6): activation and inactivation mechanisms during visual transduction in rods and cones. Pflugers Arch 2021; 473:1377-1391. [PMID: 33860373 DOI: 10.1007/s00424-021-02562-x] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2020] [Revised: 03/27/2021] [Accepted: 03/30/2021] [Indexed: 01/16/2023]
Abstract
Rod and cone photoreceptors of the vertebrate retina utilize cGMP as the primary intracellular messenger for the visual signaling pathway that converts a light stimulus into an electrical response. cGMP metabolism in the signal-transducing photoreceptor outer segment reflects the balance of cGMP synthesis (catalyzed by guanylyl cyclase) and degradation (catalyzed by the photoreceptor phosphodiesterase, PDE6). Upon light stimulation, rapid activation of PDE6 by the heterotrimeric G-protein (transducin) triggers a dramatic drop in cGMP levels that lead to cell hyperpolarization. Following cessation of the light stimulus, the lifetime of activated PDE6 is also precisely regulated by additional processes. This review summarizes recent advances in the structural characterization of the rod and cone PDE6 catalytic and regulatory subunits in the context of previous biochemical studies of the enzymological properties and allosteric regulation of PDE6. Emphasis is given to recent advances in understanding the structural and conformational changes underlying the mechanism by which the activated transducin α-subunit binds to-and relieves inhibition of-PDE6 catalysis that is controlled by its intrinsically disordered, inhibitory γ-subunit. The role of the regulator of G-protein signaling 9-1 (RGS9-1) in regulating the lifetime of the transducin-PDE6 is also briefly covered. The therapeutic potential of pharmacological compounds acting as inhibitors or activators targeting PDE6 is discussed in the context of inherited retinal diseases resulting from mutations in rod and cone PDE6 genes as well as other inherited defects that arise from excessive cGMP accumulation in retinal photoreceptor cells.
Collapse
|
34
|
Polit A, Mystek P, Błasiak E. Every Detail Matters. That Is, How the Interaction between Gα Proteins and Membrane Affects Their Function. MEMBRANES 2021; 11:222. [PMID: 33804791 PMCID: PMC8003949 DOI: 10.3390/membranes11030222] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/16/2021] [Revised: 03/17/2021] [Accepted: 03/18/2021] [Indexed: 11/16/2022]
Abstract
In highly organized multicellular organisms such as humans, the functions of an individual cell are dependent on signal transduction through G protein-coupled receptors (GPCRs) and subsequently heterotrimeric G proteins. As most of the elements belonging to the signal transduction system are bound to lipid membranes, researchers are showing increasing interest in studying the accompanying protein-lipid interactions, which have been demonstrated to not only provide the environment but also regulate proper and efficient signal transduction. The mode of interaction between the cell membrane and G proteins is well known. Despite this, the recognition mechanisms at the molecular level and how the individual G protein-membrane attachment signals are interrelated in the process of the complex control of membrane targeting of G proteins remain unelucidated. This review focuses on the mechanisms by which mammalian Gα subunits of G proteins interact with lipids and the factors responsible for the specificity of membrane association. We summarize recent data on how these signaling proteins are precisely targeted to a specific site in the membrane region by introducing well-defined modifications as well as through the presence of polybasic regions within these proteins and interactions with other components of the heterocomplex.
Collapse
Affiliation(s)
- Agnieszka Polit
- Department of Physical Biochemistry, Faculty of Biochemistry Biophysics and Biotechnology, Jagiellonian University, Gronostajowa 7, 30-387 Kraków, Poland; (P.M.); (E.B.)
| | | | | |
Collapse
|
35
|
Knight KM, Ghosh S, Campbell SL, Lefevre TJ, Olsen RHJ, Smrcka AV, Valentin NH, Yin G, Vaidehi N, Dohlman HG. A universal allosteric mechanism for G protein activation. Mol Cell 2021; 81:1384-1396.e6. [PMID: 33636126 DOI: 10.1016/j.molcel.2021.02.002] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2020] [Revised: 12/01/2020] [Accepted: 01/29/2021] [Indexed: 12/11/2022]
Abstract
G proteins play a central role in signal transduction and pharmacology. Signaling is initiated by cell-surface receptors, which promote guanosine triphosphate (GTP) binding and dissociation of Gα from the Gβγ subunits. Structural studies have revealed the molecular basis of subunit association with receptors, RGS proteins, and downstream effectors. In contrast, the mechanism of subunit dissociation is poorly understood. We use cell signaling assays, molecular dynamics (MD) simulations, and biochemistry and structural analyses to identify a conserved network of amino acids that dictates subunit release. In the presence of the terminal phosphate of GTP, a glycine forms a polar network with an arginine and glutamate, putting torsional strain on the subunit binding interface. This "G-R-E motif" secures GTP and, through an allosteric link, discharges the Gβγ dimer. Replacement of network residues prevents subunit dissociation regardless of agonist or GTP binding. These findings reveal the molecular basis of the final committed step of G protein activation.
Collapse
Affiliation(s)
- Kevin M Knight
- Department of Pharmacology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Soumadwip Ghosh
- Department of Computational and Quantitative Medicine, Beckman Research Institute of the City of Hope, Duarte, CA 91010, USA
| | - Sharon L Campbell
- Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Tyler J Lefevre
- Department of Pharmacology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Reid H J Olsen
- Department of Pharmacology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Alan V Smrcka
- Department of Pharmacology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Natalie H Valentin
- Department of Pharmacology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Guowei Yin
- Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Nagarajan Vaidehi
- Department of Computational and Quantitative Medicine, Beckman Research Institute of the City of Hope, Duarte, CA 91010, USA.
| | - Henrik G Dohlman
- Department of Pharmacology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA.
| |
Collapse
|
36
|
Therapeutic potential of targeting G protein-gated inwardly rectifying potassium (GIRK) channels in the central nervous system. Pharmacol Ther 2021; 223:107808. [PMID: 33476640 DOI: 10.1016/j.pharmthera.2021.107808] [Citation(s) in RCA: 47] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2020] [Accepted: 01/05/2021] [Indexed: 12/15/2022]
Abstract
G protein-gated inwardly rectifying potassium channels (Kir3/GirK) are important for maintaining resting membrane potential, cell excitability and inhibitory neurotransmission. Coupled to numerous G protein-coupled receptors (GPCRs), they mediate the effects of many neurotransmitters, neuromodulators and hormones contributing to the general homeostasis and particular synaptic plasticity processes, learning, memory and pain signaling. A growing number of behavioral and genetic studies suggest a critical role for the appropriate functioning of the central nervous system, as well as their involvement in many neurologic and psychiatric conditions, such as neurodegenerative diseases, mood disorders, attention deficit hyperactivity disorder, schizophrenia, epilepsy, alcoholism and drug addiction. Hence, GirK channels emerge as a very promising tool to be targeted in the current scenario where these conditions already are or will become a global public health problem. This review examines recent findings on the physiology, function, dysfunction, and pharmacology of GirK channels in the central nervous system and highlights the relevance of GirK channels as a worthful potential target to improve therapies for related diseases.
Collapse
|
37
|
Gauberg J, Abdallah S, Elkhatib W, Harracksingh AN, Piekut T, Stanley EF, Senatore A. Conserved biophysical features of the Ca V2 presynaptic Ca 2+ channel homologue from the early-diverging animal Trichoplax adhaerens. J Biol Chem 2020; 295:18553-18578. [PMID: 33097592 PMCID: PMC7939481 DOI: 10.1074/jbc.ra120.015725] [Citation(s) in RCA: 2] [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: 08/21/2020] [Revised: 10/21/2020] [Indexed: 12/20/2022] Open
Abstract
The dominant role of CaV2 voltage-gated calcium channels for driving neurotransmitter release is broadly conserved. Given the overlapping functional properties of CaV2 and CaV1 channels, and less so CaV3 channels, it is unclear why there have not been major shifts toward dependence on other CaV channels for synaptic transmission. Here, we provide a structural and functional profile of the CaV2 channel cloned from the early-diverging animal Trichoplax adhaerens, which lacks a nervous system but possesses single gene homologues for CaV1-CaV3 channels. Remarkably, the highly divergent channel possesses similar features as human CaV2.1 and other CaV2 channels, including high voltage-activated currents that are larger in external Ba2+ than in Ca2+; voltage-dependent kinetics of activation, inactivation, and deactivation; and bimodal recovery from inactivation. Altogether, the functional profile of Trichoplax CaV2 suggests that the core features of presynaptic CaV2 channels were established early during animal evolution, after CaV1 and CaV2 channels emerged via proposed gene duplication from an ancestral CaV1/2 type channel. The Trichoplax channel was relatively insensitive to mammalian CaV2 channel blockers ω-agatoxin-IVA and ω-conotoxin-GVIA and to metal cation blockers Cd2+ and Ni2+ Also absent was the capacity for voltage-dependent G-protein inhibition by co-expressed Trichoplax Gβγ subunits, which nevertheless inhibited the human CaV2.1 channel, suggesting that this modulatory capacity evolved via changes in channel sequence/structure, and not G proteins. Last, the Trichoplax channel was immunolocalized in cells that express an endomorphin-like peptide implicated in cell signaling and locomotive behavior and other likely secretory cells, suggesting contributions to regulated exocytosis.
Collapse
Affiliation(s)
- Julia Gauberg
- Department of Biology, University of Toronto Mississauga, Mississauga, Ontario, Canada
| | - Salsabil Abdallah
- Department of Biology, University of Toronto Mississauga, Mississauga, Ontario, Canada
| | - Wassim Elkhatib
- Department of Biology, University of Toronto Mississauga, Mississauga, Ontario, Canada
| | - Alicia N Harracksingh
- Department of Biology, University of Toronto Mississauga, Mississauga, Ontario, Canada
| | - Thomas Piekut
- Department of Biology, University of Toronto Mississauga, Mississauga, Ontario, Canada
| | - Elise F Stanley
- Laboratory of Synaptic Transmission, Krembil Research Institute, Toronto, Ontario, Canada
| | - Adriano Senatore
- Department of Biology, University of Toronto Mississauga, Mississauga, Ontario, Canada.
| |
Collapse
|
38
|
Calebiro D, Koszegi Z, Lanoiselée Y, Miljus T, O'Brien S. G protein-coupled receptor-G protein interactions: a single-molecule perspective. Physiol Rev 2020; 101:857-906. [PMID: 33331229 DOI: 10.1152/physrev.00021.2020] [Citation(s) in RCA: 45] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
G protein-coupled receptors (GPCRs) regulate many cellular and physiological processes, responding to a diverse range of extracellular stimuli including hormones, neurotransmitters, odorants, and light. Decades of biochemical and pharmacological studies have provided fundamental insights into the mechanisms of GPCR signaling. Thanks to recent advances in structural biology, we now possess an atomistic understanding of receptor activation and G protein coupling. However, how GPCRs and G proteins interact in living cells to confer signaling efficiency and specificity remains insufficiently understood. The development of advanced optical methods, including single-molecule microscopy, has provided the means to study receptors and G proteins in living cells with unprecedented spatio-temporal resolution. The results of these studies reveal an unexpected level of complexity, whereby GPCRs undergo transient interactions among themselves as well as with G proteins and structural elements of the plasma membrane to form short-lived signaling nanodomains that likely confer both rapidity and specificity to GPCR signaling. These findings may provide new strategies to pharmaceutically modulate GPCR function, which might eventually pave the way to innovative drugs for common diseases such as diabetes or heart failure.
Collapse
Affiliation(s)
- Davide Calebiro
- Institute of Metabolism and Systems Research, University of Birmingham, Birmingham, United Kingdom; Centre of Membrane Proteins and Receptors (COMPARE), Universities of Nottingham and Birmingham, Birmingham, United Kingdom
| | - Zsombor Koszegi
- Institute of Metabolism and Systems Research, University of Birmingham, Birmingham, United Kingdom; Centre of Membrane Proteins and Receptors (COMPARE), Universities of Nottingham and Birmingham, Birmingham, United Kingdom
| | - Yann Lanoiselée
- Institute of Metabolism and Systems Research, University of Birmingham, Birmingham, United Kingdom; Centre of Membrane Proteins and Receptors (COMPARE), Universities of Nottingham and Birmingham, Birmingham, United Kingdom
| | - Tamara Miljus
- Institute of Metabolism and Systems Research, University of Birmingham, Birmingham, United Kingdom; Centre of Membrane Proteins and Receptors (COMPARE), Universities of Nottingham and Birmingham, Birmingham, United Kingdom
| | - Shannon O'Brien
- Institute of Metabolism and Systems Research, University of Birmingham, Birmingham, United Kingdom; Centre of Membrane Proteins and Receptors (COMPARE), Universities of Nottingham and Birmingham, Birmingham, United Kingdom
| |
Collapse
|
39
|
Schultz‐Rogers L, Masuho I, Pinto e Vairo F, Schmitz CT, Schwab TL, Clark KJ, Gunderson L, Pichurin PN, Wierenga K, Martemyanov KA, Klee EW. Haploinsufficiency as a disease mechanism in GNB1-associated neurodevelopmental disorder. Mol Genet Genomic Med 2020; 8:e1477. [PMID: 32918542 PMCID: PMC7667315 DOI: 10.1002/mgg3.1477] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2020] [Revised: 08/05/2020] [Accepted: 08/06/2020] [Indexed: 12/21/2022] Open
Abstract
BACKGROUND GNB1 encodes a subunit of a heterotrimeric G-protein complex that transduces intracellular signaling cascades. Disruptions to the gene have previously been shown to be embryonic lethal in knockout mice and to cause complex neurodevelopmental disorders in humans. To date, the majority of variants associated with disease in humans have been missense variants in exons 5-7. METHODS Genetic sequencing was performed on two patients presenting with complex neurological phenotypes including intellectual disability, hypotonia, and in one patient seizures. Reported variants were assessed using RNA sequencing and functional BRET/BiFC assays. RESULTS A splice variant reported in patient 1 was confirmed to cause usage of a cryptic splice site leading to a truncated protein product. Patient 2 was reported to have a truncating variant. BRET and BiFC assays of both patient variants confirmed both were deficient in inducing GPCR-induced G protein activation due to lack of dimer formation with the Gγ subunit. CONCLUSION Here, we report two patients with functionally confirmed loss of function variants in GNB1 and neurodevelopmental phenotypes including intellectual disability, hypotonia, and seizures in one patient. These results suggest haploinsufficiency of GNB1 is a mechanism for neurodevelopmental disorders in humans.
Collapse
Affiliation(s)
| | - Ikuo Masuho
- Department of NeuroscienceThe Scripps Research InstituteJupiterFLUSA
| | - Filippo Pinto e Vairo
- Center for Individualized MedicineMayo ClinicRochesterMNUSA
- Department of Clinical GenomicsMayo ClinicRochesterMNUSA
| | | | - Tanya L. Schwab
- Department of Biochemistry and Molecular BiologyMayo ClinicRochesterMNUSA
| | - Karl J. Clark
- Department of Biochemistry and Molecular BiologyMayo ClinicRochesterMNUSA
| | | | | | - Klaas Wierenga
- Department of Medical GeneticsMayo ClinicJacksonvilleFLUSA
| | | | - Eric W. Klee
- Center for Individualized MedicineMayo ClinicRochesterMNUSA
- Department of Clinical GenomicsMayo ClinicRochesterMNUSA
| |
Collapse
|
40
|
Su M, Zhu L, Zhang Y, Paknejad N, Dey R, Huang J, Lee MY, Williams D, Jordan KD, Eng ET, Ernst OP, Meyerson JR, Hite RK, Walz T, Liu W, Huang XY. Structural Basis of the Activation of Heterotrimeric Gs-Protein by Isoproterenol-Bound β 1-Adrenergic Receptor. Mol Cell 2020; 80:59-71.e4. [PMID: 32818430 PMCID: PMC7541785 DOI: 10.1016/j.molcel.2020.08.001] [Citation(s) in RCA: 51] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2019] [Revised: 02/09/2020] [Accepted: 07/31/2020] [Indexed: 01/21/2023]
Abstract
Cardiac disease remains the leading cause of morbidity and mortality worldwide. The β1-adrenergic receptor (β1-AR) is a major regulator of cardiac functions and is downregulated in the majority of heart failure cases. A key physiological process is the activation of heterotrimeric G-protein Gs by β1-ARs, leading to increased heart rate and contractility. Here, we use cryo-electron microscopy and functional studies to investigate the molecular mechanism by which β1-AR activates Gs. We find that the tilting of α5-helix breaks a hydrogen bond between the sidechain of His373 in the C-terminal α5-helix and the backbone carbonyl of Arg38 in the N-terminal αN-helix of Gαs. Together with the disruption of another interacting network involving Gln59 in the α1-helix, Ala352 in the β6-α5 loop, and Thr355 in the α5-helix, these conformational changes might lead to the deformation of the GDP-binding pocket. Our data provide molecular insights into the activation of G-proteins by G-protein-coupled receptors.
Collapse
Affiliation(s)
- Minfei Su
- Department of Physiology and Biophysics, Weill Cornell Medical College of Cornell University, New York, NY 10065
| | - Lan Zhu
- School of Molecular Sciences and Biodesign Center for Applied Structural Discovery, Arizona State University, Tempe, AZ 85287
| | - Yixiao Zhang
- Laboratory of Molecular Electron Microscopy, The Rockefeller University, New York, NY 10065
| | - Navid Paknejad
- Structural Biology Program, Memorial Sloan Kettering Cancer Center, New York, NY 10065
| | - Raja Dey
- Department of Physiology and Biophysics, Weill Cornell Medical College of Cornell University, New York, NY 10065
| | - Jianyun Huang
- Department of Physiology and Biophysics, Weill Cornell Medical College of Cornell University, New York, NY 10065
| | - Ming-Yue Lee
- School of Molecular Sciences and Biodesign Center for Applied Structural Discovery, Arizona State University, Tempe, AZ 85287
| | - Dewight Williams
- School of Molecular Sciences and Biodesign Center for Applied Structural Discovery, Arizona State University, Tempe, AZ 85287
| | - Kelsey D. Jordan
- Department of Biochemistry, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Edward T. Eng
- Department of Biochemistry, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Oliver P. Ernst
- Simons Electron Microscopy Center, New York Structural Biology Center, New York, NY 10027,Department of Molecular Genetics, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Joel R. Meyerson
- Department of Physiology and Biophysics, Weill Cornell Medical College of Cornell University, New York, NY 10065
| | - Richard K. Hite
- Structural Biology Program, Memorial Sloan Kettering Cancer Center, New York, NY 10065
| | - Thomas Walz
- Laboratory of Molecular Electron Microscopy, The Rockefeller University, New York, NY 10065
| | - Wei Liu
- School of Molecular Sciences and Biodesign Center for Applied Structural Discovery, Arizona State University, Tempe, AZ 85287,To whom correspondence should be addressed. ;
| | - Xin-Yun Huang
- Department of Physiology and Biophysics, Weill Cornell Medical College of Cornell University, New York, NY 10065,Lead Contact,To whom correspondence should be addressed. ;
| |
Collapse
|
41
|
Wu HD, Kikuchi M, Dagliyan O, Aragaki AK, Nakamura H, Dokholyan NV, Umehara T, Inoue T. Rational design and implementation of a chemically inducible heterotrimerization system. Nat Methods 2020; 17:928-936. [PMID: 32747768 PMCID: PMC9936427 DOI: 10.1038/s41592-020-0913-x] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2020] [Accepted: 07/06/2020] [Indexed: 12/11/2022]
Abstract
Chemically inducible dimerization (CID) uses a small molecule to induce binding of two different proteins. CID tools such as the FK506-binding protein-FKBP-rapamycin-binding- (FKBP-FRB)-rapamycin system have been widely used to probe molecular events inside and outside cells. While various CID tools are available, chemically inducible trimerization (CIT) does not exist, due to inherent challenges in designing a chemical that simultaneously binds three proteins with high affinity and specificity. Here, we developed CIT by rationally splitting FRB and FKBP. Cellular and structural datasets showed efficient trimerization of split pairs of FRB or FKBP with full-length FKBP or FRB, respectively, by rapamycin. CIT rapidly induced tri-organellar junctions and perturbed intended membrane lipids exclusively at select membrane contact sites. By conferring one additional condition to what is achievable with CID, CIT expands the types of manipulation in single live cells to address cell biology questions otherwise intractable and engineer cell functions for future synthetic biology applications.
Collapse
Affiliation(s)
- Helen D. Wu
- Department of Biomedical Engineering, Johns Hopkins University School of Medicine, Baltimore, MD 21205,Department of Cell Biology, Center for Cell Dynamics, Johns Hopkins University School of Medicine, Baltimore, MD 21205
| | - Masaki Kikuchi
- Laboratory for Epigenetics Drug Discovery, RIKEN Center for Biosystems Dynamics Research, Yokohama, Kanagawa 230-0045, Japan
| | - Onur Dagliyan
- Department of Neurobiology, Harvard Medical School, Boston, MA 02115
| | - Adam K. Aragaki
- Department of Pharmacology, Johns Hopkins University School of Medicine, Baltimore, MD 21205,Department of Cell Biology, Center for Cell Dynamics, Johns Hopkins University School of Medicine, Baltimore, MD 21205
| | - Hideki Nakamura
- Department of Cell Biology, Center for Cell Dynamics, Johns Hopkins University School of Medicine, Baltimore, MD 21205,Present address: Kyoto University Graduate School of Engineering, Department of Synthetic Chemistry and Biological Chemistry, Katsura Int’tech Center, Graduate School of Engineering, Kyoto University, Nishikyo-ku, Kyoto, 615-8530, Japan
| | - Nikolay V. Dokholyan
- Departments of Pharmacology and Biochemistry & Molecular Biology, Penn State University College of Medicine, Hershey, Pennsylvania,Departments of Chemistry and Biomedical Engineering, Pennsylvania State University, University Park, Pennsylvania
| | - Takashi Umehara
- Laboratory for Epigenetics Drug Discovery, RIKEN Center for Biosystems Dynamics Research, Yokohama, Kanagawa, Japan.
| | - Takanari Inoue
- Department of Biomedical Engineering, Johns Hopkins University School of Medicine, Baltimore, MD, USA. .,Department of Cell Biology, Center for Cell Dynamics, Johns Hopkins University School of Medicine, Baltimore, MD, USA. .,Department of Pharmacology, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
| |
Collapse
|
42
|
Kumar V, Hoag H, Sader S, Scorese N, Liu H, Wu C. GDP Release from the Open Conformation of Gα Requires Allosteric Signaling from the Agonist-Bound Human β 2 Adrenergic Receptor. J Chem Inf Model 2020; 60:4064-4075. [PMID: 32786510 DOI: 10.1021/acs.jcim.0c00432] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
G-protein-coupled receptors (GPCRs) transmit signals into the cell in response to ligand binding at its extracellular domain, which is characterized by the coupling of agonist-induced receptor conformational change to guanine nucleotide (GDP) exchange with guanosine triphosphate on a heterotrimeric (αβγ) guanine nucleotide-binding protein (G-protein), leading to the activation of the G-protein. The signal transduction mechanisms have been widely researched in vivo and in silico. However, coordinated communication from stimulating ligands to the bound GDP still remains elusive. In the present study, we used microsecond (μS) molecular dynamic (MD) simulations to directly probe the communication from the β2 adrenergic receptor (β2AR) with an agonist or an antagonist or no ligand to GDP bound to the open conformation of the Gα protein. Molecular mechanism-general Born surface area calculation results indicated either the agonist or the antagonist destabilized the binding between the receptor and the G-protein but the agonist caused a higher level of destabilization than the antagonist. This is consistent with the role of agonist in the activation of the G-protein. Interestingly, while GDP remained bound with the Gα-protein for the two inactive systems (antagonist-bound and apo form), GDP dissociated from the open conformation of the Gα protein for the agonist activated system. Data obtained from MD simulations indicated that the receptor and the Gα subunit play a big role in coordinated communication and nucleotide exchange. Based on residue interaction network analysis, we observed that engagement of agonist-bound β2AR with an α5 helix of Gα is essential for the GDP release and the residues in the phosphate-binding loop, α1 helix, and α5 helix play very important roles in the GDP release. The insights on GPCR-G-protein communication will facilitate the rational design of agonists and antagonists that target both active and inactive GPCR binding pockets, leading to more precise drugs.
Collapse
Affiliation(s)
- Vikash Kumar
- Complex Systems Division, Beijing Computational Science Research Center, Haidian district, Beijing 100193, China
| | - Hannah Hoag
- College of Science and Mathematics, Rowan University, Glassboro, New Jersey 08028, United States
| | - Safaa Sader
- College of Science and Mathematics, Rowan University, Glassboro, New Jersey 08028, United States
| | - Nicolas Scorese
- College of Science and Mathematics, Rowan University, Glassboro, New Jersey 08028, United States
| | - Haiguang Liu
- Complex Systems Division, Beijing Computational Science Research Center, Haidian district, Beijing 100193, China
| | - Chun Wu
- College of Science and Mathematics, Rowan University, Glassboro, New Jersey 08028, United States
| |
Collapse
|
43
|
Zhang X. Direct Gα q Gating Is the Sole Mechanism for TRPM8 Inhibition Caused by Bradykinin Receptor Activation. Cell Rep 2020; 27:3672-3683.e4. [PMID: 31216483 PMCID: PMC6595177 DOI: 10.1016/j.celrep.2019.05.080] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2019] [Revised: 04/03/2019] [Accepted: 05/21/2019] [Indexed: 11/29/2022] Open
Abstract
Activation of Gαq-coupled receptors by inflammatory mediators inhibits cold-sensing TRPM8 channels, aggravating pain and inflammation. Both Gαq and the downstream hydrolysis of phosphatidylinositol 4, 5-bisphosphate (PIP2) inhibit TRPM8. Here, I demonstrate that direct Gαq gating is essential for both the basal cold sensitivity of TRPM8 and TRPM8 inhibition elicited by bradykinin in sensory neurons. The action of Gαq depends on binding to three arginine residues in the N terminus of TRPM8. Neutralization of these residues markedly increased sensitivity of the channel to agonist and membrane voltage and completely abolished TRPM8 inhibition by both Gαq and bradykinin while sparing the channel sensitivity to PIP2. Interestingly, the bradykinin receptor B2R also binds to TRPM8, rendering TRPM8 insensitive to PIP2 depletion. Furthermore, TRPM8-Gαq binding impaired Gαq coupling and signaling to PLCβ-PIP2. The crosstalk in the TRPM8-Gαq-B2R complex thus determines Gαq gating rather than PIP2 as a sole means of TRPM8 inhibition by bradykinin.
Collapse
Affiliation(s)
- Xuming Zhang
- School of Life and Health Sciences, Aston University, Aston Triangle, Birmingham B4 7ET, UK.
| |
Collapse
|
44
|
Chidambaram H, Chinnathambi S. G-Protein Coupled Receptors and Tau-different Roles in Alzheimer’s Disease. Neuroscience 2020; 438:198-214. [DOI: 10.1016/j.neuroscience.2020.04.019] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2019] [Revised: 04/10/2020] [Accepted: 04/15/2020] [Indexed: 01/14/2023]
|
45
|
Gu Q, Wu J, Tian Y, Cheng S, Zhang ZC, Han J. Gαq splice variants mediate phototransduction, rhodopsin synthesis, and retinal integrity in Drosophila. J Biol Chem 2020; 295:5554-5563. [PMID: 32198182 PMCID: PMC7186184 DOI: 10.1074/jbc.ra120.012764] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2020] [Revised: 03/19/2020] [Indexed: 11/06/2022] Open
Abstract
Heterotrimeric G proteins mediate a variety of signaling processes by coupling G protein-coupled receptors to intracellular effector molecules. In Drosophila, the Gαq gene encodes several Gαq splice variants, with the Gαq1 isoform protein playing a major role in fly phototransduction. However, Gαq1 null mutant flies still exhibit a residual light response, indicating that other Gαq splice variants or additional Gq α subunits are involved in phototransduction. Here, we isolated a mutant fly with no detectable light responses, decreased rhodopsin (Rh) levels, and rapid retinal degeneration. Using electrophysiological and genetic studies, biochemical assays, immunoblotting, real-time RT-PCR, and EM analysis, we found that mutations in the Gαq gene disrupt light responses and demonstrate that the Gαq3 isoform protein is responsible for the residual light response in Gαq1 null mutants. Moreover, we report that Gαq3 mediates rhodopsin synthesis. Depletion of all Gαq splice variants led to rapid light-dependent retinal degeneration, due to the formation stable Rh1-arrestin 2 (Arr2) complexes. Our findings clarify essential roles of several different Gαq splice variants in phototransduction and retinal integrity in Drosophila and reveal that Gαq3 functions in rhodopsin synthesis.
Collapse
Affiliation(s)
- Qiuxiang Gu
- School of Life Science and Technology, the Key Laboratory of Developmental Genes and Human Disease, Southeast University, Nanjing, Jiangsu 210096, China
| | - Jinglin Wu
- School of Life Science and Technology, the Key Laboratory of Developmental Genes and Human Disease, Southeast University, Nanjing, Jiangsu 210096, China
| | - Yao Tian
- School of Life Science and Technology, the Key Laboratory of Developmental Genes and Human Disease, Southeast University, Nanjing, Jiangsu 210096, China
| | - Shanshan Cheng
- School of Life Science and Technology, the Key Laboratory of Developmental Genes and Human Disease, Southeast University, Nanjing, Jiangsu 210096, China
| | - Zi Chao Zhang
- School of Life Science and Technology, the Key Laboratory of Developmental Genes and Human Disease, Southeast University, Nanjing, Jiangsu 210096, China; Co-innovation Center of Neuroregeneration, Nantong University, Nantong, Jiangsu 226001, China.
| | - Junhai Han
- School of Life Science and Technology, the Key Laboratory of Developmental Genes and Human Disease, Southeast University, Nanjing, Jiangsu 210096, China; Co-innovation Center of Neuroregeneration, Nantong University, Nantong, Jiangsu 226001, China.
| |
Collapse
|
46
|
Gigante ED, Caspary T. Signaling in the primary cilium through the lens of the Hedgehog pathway. WILEY INTERDISCIPLINARY REVIEWS-DEVELOPMENTAL BIOLOGY 2020; 9:e377. [PMID: 32084300 DOI: 10.1002/wdev.377] [Citation(s) in RCA: 38] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/10/2019] [Revised: 01/22/2020] [Accepted: 01/25/2020] [Indexed: 12/14/2022]
Abstract
Cilia are microtubule-based, cell-surface projections whose machinery is evolutionarily conserved. In vertebrates, cilia are observed on almost every cell type and are either motile or immotile. Immotile sensory, or primary cilia, are responsive to extracellular ligands and signals. Cilia can be thought of as compartments, functionally distinct from the cell that provides an environment for signaling cascades. Hedgehog is a critical developmental signaling pathway which is functionally linked to primary cilia in vertebrates. The major components of the vertebrate Hedgehog signaling pathway dynamically localize to the ciliary compartment and ciliary membrane. Critically, G-protein coupled receptor (GPCR) Smoothened, the obligate transducer of the pathway, is enriched and activated in the cilium. While Smoothened is the most intensely studied ciliary receptor, many GPCRs localize within cilia. Understanding the link between Smoothened and cilia defines common features, and distinctions, of GPCR signaling within the primary cilium. This article is categorized under: Signaling Pathways > Global Signaling Mechanisms Signaling Pathways > Cell Fate Signaling.
Collapse
Affiliation(s)
- Eduardo D Gigante
- Graduate Program in Neuroscience, Department of Human Genetics, Emory University School of Medicine, Atlanta, Georgia, USA
| | - Tamara Caspary
- Department of Human Genetics, Emory University School of Medicine, Atlanta, Georgia, USA
| |
Collapse
|
47
|
Li J, Ge Y, Huang JX, Strømgaard K, Zhang X, Xiong XF. Heterotrimeric G Proteins as Therapeutic Targets in Drug Discovery. J Med Chem 2019; 63:5013-5030. [PMID: 31841625 DOI: 10.1021/acs.jmedchem.9b01452] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Heterotrimeric G proteins are molecular switches in GPCR signaling pathways and regulate a plethora of physiological and pathological processes. GPCRs are efficient drug targets, and more than 30% of the drugs in use target them. However, selectively targeting an individual GPCR may be undesirable in various multifactorial diseases in which multiple receptors are involved. In addition, abnormal activation or expression of G proteins is frequently associated with diseases. Furthermore, G proteins harboring mutations often result in malignant diseases. Thus, targeting G proteins instead of GPCRs might provide alternative approaches for combating these diseases. In this review, we discuss the biochemistry of heterotrimeric G proteins, describe the G protein-associated diseases, and summarize the currently known modulators that can regulate the activities of G proteins. The outlook for targeting G proteins to treat diverse diseases is also included in this manuscript.
Collapse
Affiliation(s)
- Jian Li
- Guangdong Key Laboratory of Chiral Molecule and Drug Discovery, School of Pharmaceutical Sciences, Sun Yat-sen University, 510006 Guangzhou, Guangdong, P. R. China
| | - Yang Ge
- Guangdong Key Laboratory of Chiral Molecule and Drug Discovery, School of Pharmaceutical Sciences, Sun Yat-sen University, 510006 Guangzhou, Guangdong, P. R. China
| | - Jun-Xiang Huang
- Guangdong Key Laboratory of Chiral Molecule and Drug Discovery, School of Pharmaceutical Sciences, Sun Yat-sen University, 510006 Guangzhou, Guangdong, P. R. China
| | - Kristian Strømgaard
- Department of Drug Design and Pharmacology, University of Copenhagen, Universitetsparken 2, DK-2100 Copenhagen, Denmark
| | - Xiaolei Zhang
- Guangdong Key Laboratory of Chiral Molecule and Drug Discovery, School of Pharmaceutical Sciences, Sun Yat-sen University, 510006 Guangzhou, Guangdong, P. R. China
| | - Xiao-Feng Xiong
- Guangdong Key Laboratory of Chiral Molecule and Drug Discovery, School of Pharmaceutical Sciences, Sun Yat-sen University, 510006 Guangzhou, Guangdong, P. R. China
| |
Collapse
|
48
|
Jia H, Song G, Werth EG, Walley JW, Hicks LM, Jones AM. Receptor-Like Kinase Phosphorylation of Arabidopsis Heterotrimeric G-Protein Gα -Subunit AtGPA1. Proteomics 2019; 19:e1900265. [PMID: 31693794 PMCID: PMC7014827 DOI: 10.1002/pmic.201900265] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2019] [Revised: 10/04/2019] [Indexed: 01/07/2023]
Abstract
As molecular on-off switches, heterotrimeric G protein complexes, comprised of a Gα subunit and an obligate Gβγ dimer, transmit extracellular signals received by G protein-coupled receptors (GPCRs) to cytoplasmic targets that respond to biotic and abiotic stimuli. Signal transduction is modulated by phosphorylation of GPCRs and G protein complexes. In Arabidopsis thaliana, the Gα subunit AtGPA1 is phosphorylated by the receptor-like kinase (RLK) BRI1-associated Kinase 1 (BAK1), but the extent that other RLKs phosphorylates AtGPA1 is unknown. Twenty-two trans-phosphorylation sites on AtGPA1 are mapped by 12 RLKs hypothesized to act in the Arabidopsis G protein signaling pathway. Cis-phosphorylation sites are also identified on these RLKs, some newly shown to be dual specific kinases. Multiple sites are present in the core AtGPA1 functional units, including pSer52 and/or pThr53 of the conserved P-loop that directly binds nucleotide/phosphate, pThr164, and pSer175 from αE helix in the intramolecular domain interface for nucleotide exchange and GTP hydrolysis, and pThr193 and/or pThr194 in Switch I (SwI) that coordinates nucleotide exchange and protein partner binding. Several AtGPA1 S/T phosphorylation sites are potentially nucleotide-dependent phosphorylation patterns, such as Ser52/Thr53 in the P-loop and Thr193 and/or Thr194 in SwI.
Collapse
Affiliation(s)
- Haiyan Jia
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA
| | - Gaoyuan Song
- Department of Plant Pathology and Microbiology, Iowa State University, Ames, IA, 50011, USA
| | - Emily G Werth
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA
| | - Justin W Walley
- Department of Plant Pathology and Microbiology, Iowa State University, Ames, IA, 50011, USA
| | - Leslie M Hicks
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA
| | - Alan M Jones
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA
- Department of Pharmacology, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA
| |
Collapse
|
49
|
Smrcka AV, Fisher I. G-protein βγ subunits as multi-functional scaffolds and transducers in G-protein-coupled receptor signaling. Cell Mol Life Sci 2019; 76:4447-4459. [PMID: 31435698 PMCID: PMC6842434 DOI: 10.1007/s00018-019-03275-2] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2019] [Revised: 08/05/2019] [Accepted: 08/12/2019] [Indexed: 02/08/2023]
Abstract
G-protein βγ subunits are key participants in G-protein signaling. These subunits facilitate interactions between receptors and G proteins that are critical for the G protein activation cycle at the plasma membrane. In addition, they play roles in directly transducing signals to an ever expanding range of downstream targets, including integral membrane and cytosolic proteins. Emerging data indicate that Gβγ may play additional roles at intracellular compartments including endosomes, the Golgi apparatus, and the nucleus. Here, we discuss the molecular and structural basis for their ability to coordinate this wide range of cellular activities.
Collapse
Affiliation(s)
- Alan V Smrcka
- Department of Pharmacology, University of Michigan Medical School, Ann Arbor, MI, 48104, USA.
| | - Isaac Fisher
- Department of Pharmacology, University of Michigan Medical School, Ann Arbor, MI, 48104, USA
- Department of Pharmacology and Physiology, University of Rochester School of Medicine, Rochester, NY, 14629, USA
| |
Collapse
|
50
|
Mystek P, Rysiewicz B, Gregrowicz J, Dziedzicka-Wasylewska M, Polit A. Gγ and Gα Identity Dictate a G-Protein Heterotrimer Plasma Membrane Targeting. Cells 2019; 8:E1246. [PMID: 31614907 PMCID: PMC6829862 DOI: 10.3390/cells8101246] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2019] [Revised: 10/10/2019] [Accepted: 10/11/2019] [Indexed: 12/18/2022] Open
Abstract
Heterotrimeric G-proteins along with G-protein-coupled receptors (GPCRs) regulate many biochemical functions by relaying the information from the plasma membrane to the inside of the cell. The lipid modifications of Gα and Gγ subunits, together with the charged regions on the membrane interaction surface, provide a peculiar pattern for various heterotrimeric complexes. In a previous study, we found that Gαs and Gαi3 prefer different types of membrane-anchor and subclass-specific lipid domains. In the present report, we examine the role of distinct Gγ subunits in the membrane localization and spatiotemporal dynamics of Gαs and Gαi3 heterotrimers. We characterized lateral diffusion and G-protein subunit interactions in living cells using fluorescence recovery after photobleaching (FRAP) microscopy and fluorescence resonance energy transfer (FRET) detected by fluorescence lifetime imaging microscopy (FLIM), respectively. The interaction of Gγ subunits with specific lipids was confirmed, and thus the modulation of heterotrimeric G-protein localization. However, the Gα subunit also modulates trimer localization, and so the membrane distribution of heterotrimeric G-proteins is not dependent on Gγ only.
Collapse
Affiliation(s)
- Paweł Mystek
- Department of Physical Biochemistry, Faculty of Biochemistry Biophysics and Biotechnology, Jagiellonian University, Gronostajowa 7, 30-387 Kraków, Poland.
| | - Beata Rysiewicz
- Department of Physical Biochemistry, Faculty of Biochemistry Biophysics and Biotechnology, Jagiellonian University, Gronostajowa 7, 30-387 Kraków, Poland.
| | - Jan Gregrowicz
- Department of Physical Biochemistry, Faculty of Biochemistry Biophysics and Biotechnology, Jagiellonian University, Gronostajowa 7, 30-387 Kraków, Poland.
| | - Marta Dziedzicka-Wasylewska
- Department of Physical Biochemistry, Faculty of Biochemistry Biophysics and Biotechnology, Jagiellonian University, Gronostajowa 7, 30-387 Kraków, Poland.
| | - Agnieszka Polit
- Department of Physical Biochemistry, Faculty of Biochemistry Biophysics and Biotechnology, Jagiellonian University, Gronostajowa 7, 30-387 Kraków, Poland.
| |
Collapse
|