1
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Gookin TE, Chakravorty D, Assmann SM. Influence of expression and purification protocols on Gα biochemical activity: kinetics of plant and mammalian G protein cycles. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.05.10.540258. [PMID: 37214830 PMCID: PMC10197700 DOI: 10.1101/2023.05.10.540258] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Heterotrimeric G proteins are a class of signal transduction complexes with broad roles in human health and agriculturally important plant traits. In the classic paradigm, guanine nucleotide binding to the Gα subunit regulates the activation status of the complex. Using the Arabidopsis thaliana Gα subunit, GPA1, we developed a rapid StrepII-tag mediated purification method that facilitates isolation of protein with increased enzymatic activities as compared to conventional methods, and is demonstrably also applicable to mammalian Gα subunits. We subsequently utilized domain swaps of GPA1 and human GNAO1 to demonstrate the instability of recombinant GPA1 is a function of the interaction between the Ras and helical domains, and can be partially uncoupled from the rapid nucleotide binding kinetics displayed by GPA1.
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Affiliation(s)
- Timothy E. Gookin
- Biology Department, Pennsylvania State University, University Park, Pennsylvania 16802
- These authors contributed equally to the article
| | - David Chakravorty
- Biology Department, Pennsylvania State University, University Park, Pennsylvania 16802
- These authors contributed equally to the article
| | - Sarah M. Assmann
- Biology Department, Pennsylvania State University, University Park, Pennsylvania 16802
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2
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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.
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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
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3
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Dmitrieva DA, Kotova TV, Safronova NA, Sadova AA, Dashevskii DE, Mishin AV. Protein Design Strategies for the Structural–Functional Studies of G Protein-Coupled Receptors. BIOCHEMISTRY (MOSCOW) 2023; 88:S192-S226. [PMID: 37069121 DOI: 10.1134/s0006297923140110] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/22/2023]
Abstract
G protein-coupled receptors (GPCRs) are an important family of membrane proteins responsible for many physiological functions in human body. High resolution GPCR structures are required to understand their molecular mechanisms and perform rational drug design, as GPCRs play a crucial role in a variety of diseases. That is difficult to obtain for the wild-type proteins because of their low stability. In this review, we discuss how this problem can be solved by using protein design strategies developed to obtain homogeneous stabilized GPCR samples for crystallization and cryoelectron microscopy.
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Affiliation(s)
- Daria A Dmitrieva
- Research Center for Molecular Mechanisms of Aging and Age-Related Diseases, Moscow Institute of Physics and Technology, Dolgoprudny, Moscow Region, 141701, Russia
| | - Tatiana V Kotova
- Research Center for Molecular Mechanisms of Aging and Age-Related Diseases, Moscow Institute of Physics and Technology, Dolgoprudny, Moscow Region, 141701, Russia
| | - Nadezda A Safronova
- Research Center for Molecular Mechanisms of Aging and Age-Related Diseases, Moscow Institute of Physics and Technology, Dolgoprudny, Moscow Region, 141701, Russia
| | - Alexandra A Sadova
- Research Center for Molecular Mechanisms of Aging and Age-Related Diseases, Moscow Institute of Physics and Technology, Dolgoprudny, Moscow Region, 141701, Russia
| | - Dmitrii E Dashevskii
- Research Center for Molecular Mechanisms of Aging and Age-Related Diseases, Moscow Institute of Physics and Technology, Dolgoprudny, Moscow Region, 141701, Russia
| | - Alexey V Mishin
- Research Center for Molecular Mechanisms of Aging and Age-Related Diseases, Moscow Institute of Physics and Technology, Dolgoprudny, Moscow Region, 141701, Russia.
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4
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Insights into divalent cation regulation and G 13-coupling of orphan receptor GPR35. Cell Discov 2022; 8:135. [PMID: 36543774 PMCID: PMC9772185 DOI: 10.1038/s41421-022-00499-8] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2022] [Accepted: 10/28/2022] [Indexed: 12/24/2022] Open
Abstract
Endogenous ions play important roles in the function and pharmacology of G protein-coupled receptors (GPCRs) with limited atomic evidence. In addition, compared with G protein subtypes Gs, Gi/o, and Gq/11, insufficient structural evidence is accessible to understand the coupling mechanism of G12/13 protein by GPCRs. Orphan receptor GPR35, which is predominantly expressed in the gastrointestinal tract and is closely related to inflammatory bowel diseases (IBDs), stands out as a prototypical receptor for investigating ionic modulation and G13 coupling. Here we report a cryo-electron microscopy structure of G13-coupled GPR35 bound to an anti-allergic drug, lodoxamide. This structure reveals a novel divalent cation coordination site and a unique ionic regulatory mode of GPR35 and also presents a highly positively charged binding pocket and the complementary electrostatic ligand recognition mode, which explain the promiscuity of acidic ligand binding by GPR35. Structural comparison of the GPR35-G13 complex with other G protein subtypes-coupled GPCRs reveals a notable movement of the C-terminus of α5 helix of the Gα13 subunit towards the receptor core and the least outward displacement of the cytoplasmic end of GPR35 TM6. A featured 'methionine pocket' contributes to the G13 coupling by GPR35. Together, our findings provide a structural basis for divalent cation modulation, ligand recognition, and subsequent G13 protein coupling of GPR35 and offer a new opportunity for designing GPR35-targeted drugs for the treatment of IBDs.
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5
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Qian Y, Ma Z, Liu C, Li X, Zhu X, Wang N, Xu Z, Xia R, Liang J, Duan Y, Yin H, Xiong Y, Zhang A, Guo C, Chen Z, Huang Z, He Y. Structural insights into adhesion GPCR ADGRL3 activation and G q, G s, G i, and G 12 coupling. Mol Cell 2022; 82:4340-4352.e6. [PMID: 36309016 DOI: 10.1016/j.molcel.2022.10.009] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2022] [Revised: 06/07/2022] [Accepted: 10/05/2022] [Indexed: 11/18/2022]
Abstract
Adhesion G-protein-coupled receptors (aGPCRs) play key roles in a diversity of physiologies. A hallmark of aGPCR activation is the removal of the inhibitory GAIN domain and the dipping of the cleaved stalk peptide into the ligand-binding pocket of receptors; however, the detailed mechanism remains obscure. Here, we present cryoelectron microscopy (cryo-EM) structures of ADGRL3 in complex with Gq, Gs, Gi, and G12. The structures reveal unique ligand-engaging mode, distinctive activation conformation, and key mechanisms of aGPCR activation. The structures also reveal the uncharted structural information of GPCR/G12 coupling. A comparison of Gq, Gs, Gi, and G12 engagements with ADGRL3 reveals the key determinant of G-protein coupling on the far end of αH5 of Gα. A detailed analysis of the engagements allows us to design mutations that specifically enhance one pathway over others. Taken together, our study lays the groundwork for understanding aGPCR activation and G-protein-coupling selectivity.
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Affiliation(s)
- Yu Qian
- Laboratory of Receptor Structure and Signaling, HIT Center for Life Sciences, Harbin Institute of Technology, Harbin 150001, China; HIT Center for Life Sciences, School of Life Science and Technology, Harbin Institute of Technology, Harbin 150080, China
| | - Zhengxiong Ma
- Laboratory of Receptor Structure and Signaling, HIT Center for Life Sciences, Harbin Institute of Technology, Harbin 150001, China
| | - Chunhong Liu
- HIT Center for Life Sciences, School of Life Science and Technology, Harbin Institute of Technology, Harbin 150080, China
| | - Xinzhi Li
- HIT Center for Life Sciences, School of Life Science and Technology, Harbin Institute of Technology, Harbin 150080, China
| | - Xinyan Zhu
- Laboratory of Receptor Structure and Signaling, HIT Center for Life Sciences, Harbin Institute of Technology, Harbin 150001, China
| | - Na Wang
- Laboratory of Receptor Structure and Signaling, HIT Center for Life Sciences, Harbin Institute of Technology, Harbin 150001, China
| | - Zhenmei Xu
- Laboratory of Receptor Structure and Signaling, HIT Center for Life Sciences, Harbin Institute of Technology, Harbin 150001, China
| | - Ruixue Xia
- Laboratory of Receptor Structure and Signaling, HIT Center for Life Sciences, Harbin Institute of Technology, Harbin 150001, China
| | - Jiale Liang
- Laboratory of Receptor Structure and Signaling, HIT Center for Life Sciences, Harbin Institute of Technology, Harbin 150001, China
| | - Yaning Duan
- Laboratory of Receptor Structure and Signaling, HIT Center for Life Sciences, Harbin Institute of Technology, Harbin 150001, China
| | - Han Yin
- Laboratory of Receptor Structure and Signaling, HIT Center for Life Sciences, Harbin Institute of Technology, Harbin 150001, China
| | - Yangjie Xiong
- Laboratory of Receptor Structure and Signaling, HIT Center for Life Sciences, Harbin Institute of Technology, Harbin 150001, China
| | - Anqi Zhang
- HIT Center for Life Sciences, School of Life Science and Technology, Harbin Institute of Technology, Harbin 150080, China
| | - Changyou Guo
- HIT Center for Life Sciences, School of Life Science and Technology, Harbin Institute of Technology, Harbin 150080, China
| | - Zheng Chen
- HIT Center for Life Sciences, School of Life Science and Technology, Harbin Institute of Technology, Harbin 150080, China
| | - Zhiwei Huang
- HIT Center for Life Sciences, School of Life Science and Technology, Harbin Institute of Technology, Harbin 150080, China
| | - Yuanzheng He
- Laboratory of Receptor Structure and Signaling, HIT Center for Life Sciences, Harbin Institute of Technology, Harbin 150001, China.
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6
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Dai SA, Hu Q, Gao R, Blythe EE, Touhara KK, Peacock H, Zhang Z, von Zastrow M, Suga H, Shokat KM. State-selective modulation of heterotrimeric Gαs signaling with macrocyclic peptides. Cell 2022; 185:3950-3965.e25. [PMID: 36170854 PMCID: PMC9747239 DOI: 10.1016/j.cell.2022.09.019] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2022] [Revised: 08/08/2022] [Accepted: 09/07/2022] [Indexed: 01/26/2023]
Abstract
The G protein-coupled receptor cascade leading to production of the second messenger cAMP is replete with pharmacologically targetable proteins, with the exception of the Gα subunit, Gαs. GTPases remain largely undruggable given the difficulty of displacing high-affinity guanine nucleotides and the lack of other drug binding sites. We explored a chemical library of 1012 cyclic peptides to expand the chemical search for inhibitors of this enzyme class. We identified two macrocyclic peptides, GN13 and GD20, that antagonize the active and inactive states of Gαs, respectively. Both macrocyclic peptides fine-tune Gαs activity with high nucleotide-binding-state selectivity and G protein class-specificity. Co-crystal structures reveal that GN13 and GD20 distinguish the conformational differences within the switch II/α3 pocket. Cell-permeable analogs of GN13 and GD20 modulate Gαs/Gβγ signaling in cells through binding to crystallographically defined pockets. The discovery of cyclic peptide inhibitors targeting Gαs provides a path for further development of state-dependent GTPase inhibitors.
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Affiliation(s)
- Shizhong A Dai
- Department of Cellular and Molecular Pharmacology, University of California, San Francisco, San Francisco, CA 94158, USA; Howard Hughes Medical Institute, Chevy Chase, MD 20815, USA
| | - Qi Hu
- Department of Cellular and Molecular Pharmacology, University of California, San Francisco, San Francisco, CA 94158, USA; Howard Hughes Medical Institute, Chevy Chase, MD 20815, USA
| | - Rong Gao
- Department of Chemistry, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Emily E Blythe
- Department of Cellular and Molecular Pharmacology, University of California, San Francisco, San Francisco, CA 94158, USA; Department of Psychiatry, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Kouki K Touhara
- Department of Physiology, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Hayden Peacock
- Department of Chemistry, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Ziyang Zhang
- Department of Cellular and Molecular Pharmacology, University of California, San Francisco, San Francisco, CA 94158, USA; Howard Hughes Medical Institute, Chevy Chase, MD 20815, USA
| | - Mark von Zastrow
- Department of Cellular and Molecular Pharmacology, University of California, San Francisco, San Francisco, CA 94158, USA; Department of Psychiatry, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Hiroaki Suga
- Department of Chemistry, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.
| | - Kevan M Shokat
- Department of Cellular and Molecular Pharmacology, University of California, San Francisco, San Francisco, CA 94158, USA; Howard Hughes Medical Institute, Chevy Chase, MD 20815, USA.
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7
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Zhu X, Qian Y, Li X, Xu Z, Xia R, Wang N, Liang J, Yin H, Zhang A, Guo C, Wang G, He Y. Structural basis of adhesion GPCR GPR110 activation by stalk peptide and G-proteins coupling. Nat Commun 2022; 13:5513. [PMID: 36127364 PMCID: PMC9489763 DOI: 10.1038/s41467-022-33173-4] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2022] [Accepted: 09/01/2022] [Indexed: 11/20/2022] Open
Abstract
Adhesion G protein-coupled receptors (aGPCRs) are keys of many physiological events and attractive targets for various diseases. aGPCRs are also known to be capable of self-activation via an autoproteolysis process that removes the inhibitory GAIN domain on the extracellular side of receptor and releases a stalk peptide to bind and activate the transmembrane side of receptor. However, the detailed mechanism of aGPCR activation remains elusive. Here, we report the cryo-electron microscopy structures of GPR110 (ADGRF1), a member of aGPCR, in complex with Gq, Gs, Gi, G12 and G13. The structures reveal distinctive ligand engaging model and activation conformations of GPR110. The structures also unveil the rarely explored GPCR/G12 and GPCR/G13 engagements. A comparison of Gq, Gs, Gi, G12 and G13 engagements with GPR110 reveals details of G-protein engagement, including a dividing point at the far end of the alpha helix 5 (αH5) of Gα subunit that separates Gq/Gs engagements from Gi/G12/G13 engagements. This is also where Gq/Gs bind the receptor through both hydrophobic and polar interaction, while Gi/G12/G13 engage receptor mainly through hydrophobic interaction. We further provide physiological evidence of GPR110 activation via stalk peptide. Taken together, our study fills the missing information of GPCR/G-protein engagement and provides a framework for understanding aGPCR activation and GPR110 signaling. aGPCRs play key roles in multiple physiological processes. Here the authors report cryo-EM structures of GPR110 in complexes with Gq, Gs, Gi, G12 and G13 protein to reveal a detailed mechanism of aGPCR activation via the tethered stalk peptide and principles of G-protein coupling and selectivity on GPR110.
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Affiliation(s)
- Xinyan Zhu
- Laboratory of Receptor Structure and Signaling, HIT Center for Life Sciences, Harbin Institute of Technology, Harbin, 150001, China
| | - Yu Qian
- Laboratory of Receptor Structure and Signaling, HIT Center for Life Sciences, Harbin Institute of Technology, Harbin, 150001, China
| | - Xiaowan Li
- Laboratory of Neuroscience, HIT Center for Life Sciences, Harbin Institute of Technology, Harbin, 150001, China
| | - Zhenmei Xu
- Laboratory of Receptor Structure and Signaling, HIT Center for Life Sciences, Harbin Institute of Technology, Harbin, 150001, China
| | - Ruixue Xia
- Laboratory of Receptor Structure and Signaling, HIT Center for Life Sciences, Harbin Institute of Technology, Harbin, 150001, China
| | - Na Wang
- Laboratory of Receptor Structure and Signaling, HIT Center for Life Sciences, Harbin Institute of Technology, Harbin, 150001, China
| | - Jiale Liang
- Laboratory of Receptor Structure and Signaling, HIT Center for Life Sciences, Harbin Institute of Technology, Harbin, 150001, China
| | - Han Yin
- Laboratory of Receptor Structure and Signaling, HIT Center for Life Sciences, Harbin Institute of Technology, Harbin, 150001, China
| | - Anqi Zhang
- HIT Center for Life Sciences, School of Life Science and Technology, Harbin Institute of Technology, Harbin, China
| | - Changyou Guo
- HIT Center for Life Sciences, School of Life Science and Technology, Harbin Institute of Technology, Harbin, China
| | - Guangfu Wang
- Laboratory of Neuroscience, HIT Center for Life Sciences, Harbin Institute of Technology, Harbin, 150001, China
| | - Yuanzheng He
- Laboratory of Receptor Structure and Signaling, HIT Center for Life Sciences, Harbin Institute of Technology, Harbin, 150001, China.
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8
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Chen H, Chen K, Huang W, Staudt LM, Cyster JG, Li X. Structure of S1PR2-heterotrimeric G 13 signaling complex. SCIENCE ADVANCES 2022; 8:eabn0067. [PMID: 35353559 PMCID: PMC8967229 DOI: 10.1126/sciadv.abn0067] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/27/2021] [Accepted: 02/07/2022] [Indexed: 06/01/2023]
Abstract
Sphingosine-1-phosphate (S1P) regulates immune cell trafficking, angiogenesis, and vascular function via its five receptors. Inherited mutations in S1P receptor 2 (S1PR2) occur in individuals with hearing loss, and acquired mutations in S1PR2 and Gα13 occur in a malignant lymphoma. Here, we present the cryo-electron microscopy structure of S1P-bound S1PR2 coupled to the heterotrimeric G13. Interaction between S1PR2 intracellular loop 2 (ICL2) and transmembrane helix 4 confines ICL2 to engage the α5 helix of Gα13. Transforming growth factor-α shedding assays and cell migration assays support the key roles of the residues in S1PR2-Gα13 complex assembly. The structure illuminates the mechanism of receptor disruption by disease-associated mutations. Unexpectedly, we showed that FTY720-P, an agonist of the other four S1PRs, can trigger G13 activation via S1PR2. S1PR2F274I variant can increase the activity of G13 considerably with FTY720-P and S1P, thus revealing a basis for S1PR drug selectivity.
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Affiliation(s)
- Hongwen Chen
- Department of Molecular Genetics, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Kevin Chen
- Department of Microbiology and Immunology, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Weijiao Huang
- Department of Molecular Genetics, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Louis M. Staudt
- Lymphoid Malignancies Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Jason G. Cyster
- Department of Microbiology and Immunology, University of California, San Francisco, San Francisco, CA 94143, USA
- Howard Hughes Medical Institute, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Xiaochun Li
- Department of Molecular Genetics, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
- Department of Biophysics, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
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9
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The tethered peptide activation mechanism of adhesion GPCRs. Nature 2022; 604:757-762. [PMID: 35418682 PMCID: PMC9841879 DOI: 10.1038/s41586-022-04575-7] [Citation(s) in RCA: 53] [Impact Index Per Article: 26.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2021] [Accepted: 02/23/2022] [Indexed: 01/18/2023]
Abstract
Adhesion G-protein-coupled receptors (aGPCRs) are characterized by the presence of auto-proteolysing extracellular regions that are involved in cell-cell and cell-extracellular matrix interactions1. Self cleavage within the aGPCR auto-proteolysis-inducing (GAIN) domain produces two protomers-N-terminal and C-terminal fragments-that remain non-covalently attached after receptors reach the cell surface1. Upon dissociation of the N-terminal fragment, the C-terminus of the GAIN domain acts as a tethered agonist (TA) peptide to activate the seven-transmembrane domain with a mechanism that has been poorly understood2-5. Here we provide cryo-electron microscopy snapshots of two distinct members of the aGPCR family, GPR56 (also known as ADGRG1) and latrophilin 3 (LPHN3 (also known as ADGRL3)). Low-resolution maps of the receptors in their N-terminal fragment-bound state indicate that the GAIN domain projects flexibly towards the extracellular space, keeping the encrypted TA peptide away from the seven-transmembrane domain. High-resolution structures of GPR56 and LPHN3 in their active, G-protein-coupled states, reveal that after dissociation of the extracellular region, the decrypted TA peptides engage the seven-transmembrane domain core with a notable conservation of interactions that also involve extracellular loop 2. TA binding stabilizes breaks in the middle of transmembrane helices 6 and 7 that facilitate aGPCR coupling and activation of heterotrimeric G proteins. Collectively, these results enable us to propose a general model for aGPCR activation.
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10
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Pei X, Liu J, Liu M, Zhou H, Wang X, Fan H. Quantitative proteomics revealed modulation of macrophages by MetQ gene of Streptococcus suis serotype 2. AMB Express 2020; 10:195. [PMID: 33125582 PMCID: PMC7599288 DOI: 10.1186/s13568-020-01131-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2020] [Accepted: 10/18/2020] [Indexed: 11/10/2022] Open
Abstract
Streptococcus suis serotype 2 (SS2) is a serious zoonotic pathogen; it can lead to symptoms of streptococcal toxic shock syndrome (STSS) in humans and sepsis in pigs, and poses a great threat to public health. The SS2 MetQ gene deletion strain has attenuated antiphagocytosis, although the mechanism of antiphagocytosis and pathogenesis of MetQ in SS2 has remained unclear. In this study, stable isotope labeling by amino acids in cell culture (SILAC) based liquid chromatography–mass spectrometry (LC–MS) and subsequent bioinformatics analysis was used to determine differentially expressed proteins of RAW264.7 cells infected with △MetQ and ZY05719. Proteomic results were verified by quantitative real-time polymerase chain reaction (qRT-PCR) and Western blotting for selected proteins. Further research was focused mainly on immune system processes related to downregulated proteins, such as Src and Ccl9, and actin cytoskeleton and endocytosis related upregulated proteins, like Pstpip1 and Ppp1r9b. The proteomic results in this study shed light on the mechanism of antiphagocytosis and innate immunity of macrophages infected with △MetQ and ZY05719, which might provide novel targets to prevent or control the infection of SS2.
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11
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Stecky RC, Quick CR, Fleming TL, Mull ML, Vinson VK, Whitley MS, Dover EN, Meigs TE. Divergent C-terminal motifs in Gα12 and Gα13 provide distinct mechanisms of effector binding and SRF activation. Cell Signal 2020; 72:109653. [PMID: 32330601 DOI: 10.1016/j.cellsig.2020.109653] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2020] [Revised: 04/19/2020] [Accepted: 04/19/2020] [Indexed: 11/18/2022]
Abstract
The G12/13 subfamily of heterotrimeric guanine nucleotide binding proteins comprises the α subunits Gα12 and Gα13, which transduce signals for cell growth, cytoskeletal rearrangements, and oncogenic transformation. In an increasing range of cancers, overexpressed Gα12 or Gα13 are implicated in aberrant cell proliferation and/or metastatic invasion. Although Gα12 and Gα13 bind non-redundant sets of effector proteins and participate in unique signalling pathways, the structural features responsible for functional differences between these α subunits are largely unknown. Invertebrates encode a single G12/13 homolog that participates in cytoskeletal changes yet appears to lack signalling to SRF (serum response factor), a transcriptional activator stimulated by mammalian Gα12 and Gα13 to promote growth and tumorigenesis. Our previous studies identified an evolutionarily divergent region in Gα12 for which replacement by homologous sequence from Drosophila melanogaster abolished SRF signalling, whereas the same invertebrate substitution was fully tolerated in Gα13 [Montgomery et al. (2014) Mol. Pharmacol. 85: 586]. These findings prompted our current approach of evolution-guided mutagenesis to identify fine structural features of Gα12 and Gα13 that underlie their respective SRF activation mechanisms. Our results identified two motifs flanking the α4 helix that play a key role in Gα12 signalling to SRF. We found the region encompassing these motifs to provide an interacting surface for multiple Gα12-specific target proteins that fail to bind Gα13. Adjacent to this divergent region, a highly-conserved domain was vital for SRF activation by both Gα12 and Gα13. However, dissection of this domain using invertebrate substitutions revealed different signalling mechanisms in these α subunits and identified Gα13-specific determinants of binding Rho-specific guanine nucleotide exchange factors. Furthermore, invertebrate substitutions in the C-terminal, α5 helical region were selectively disruptive to Gα12 signalling. Taken together, our results identify key structural features near the C-terminus that evolved after the divergence of Gα12 and Gα13, and should aid the development of agents to selectively manipulate signalling by individual α subunits of the G12/13 subfamily.
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Affiliation(s)
- Rebecca C Stecky
- Department of Biology, University of North Carolina Asheville, One University Heights, Asheville, NC 28804, United States of America
| | - Courtney R Quick
- Department of Biology, University of North Carolina Asheville, One University Heights, Asheville, NC 28804, United States of America
| | - Todd L Fleming
- Department of Biology, University of North Carolina Asheville, One University Heights, Asheville, NC 28804, United States of America
| | - Makenzy L Mull
- Department of Biology, University of North Carolina Asheville, One University Heights, Asheville, NC 28804, United States of America
| | - Vanessa K Vinson
- Department of Biology, University of North Carolina Asheville, One University Heights, Asheville, NC 28804, United States of America
| | - Megan S Whitley
- Department of Biology, University of North Carolina Asheville, One University Heights, Asheville, NC 28804, United States of America
| | - E Nicole Dover
- Department of Biology, University of North Carolina Asheville, One University Heights, Asheville, NC 28804, United States of America
| | - Thomas E Meigs
- Department of Biology, University of North Carolina Asheville, One University Heights, Asheville, NC 28804, United States of America.
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12
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Subramanian A, Capalbo A, Iyengar NR, Rizzo R, di Campli A, Di Martino R, Lo Monte M, Beccari AR, Yerudkar A, Del Vecchio C, Glielmo L, Turacchio G, Pirozzi M, Kim SG, Henklein P, Cancino J, Parashuraman S, Diviani D, Fanelli F, Sallese M, Luini A. Auto-regulation of Secretory Flux by Sensing and Responding to the Folded Cargo Protein Load in the Endoplasmic Reticulum. Cell 2020; 176:1461-1476.e23. [PMID: 30849374 DOI: 10.1016/j.cell.2019.01.035] [Citation(s) in RCA: 46] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2018] [Revised: 08/30/2018] [Accepted: 01/23/2019] [Indexed: 11/19/2022]
Abstract
Maintaining the optimal performance of cell processes and organelles is the task of auto-regulatory systems. Here we describe an auto-regulatory device that helps to maintain homeostasis of the endoplasmic reticulum (ER) by adjusting the secretory flux to the cargo load. The cargo-recruiting subunit of the coatomer protein II (COPII) coat, Sec24, doubles as a sensor of folded cargo and, upon cargo binding, acts as a guanine nucleotide exchange factor to activate the signaling protein Gα12 at the ER exit sites (ERESs). This step, in turn, activates a complex signaling network that activates and coordinates the ER export machinery and attenuates proteins synthesis, thus preventing large fluctuations of folded and potentially active cargo that could be harmful to the cell or the organism. We call this mechanism AREX (autoregulation of ER export) and expect that its identification will aid our understanding of human physiology and diseases that develop from secretory dysfunction.
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Affiliation(s)
- Advait Subramanian
- Institute of Protein Biochemistry (IBP), Italian National Research Council (CNR), Napoli, Italy.
| | - Anita Capalbo
- Institute of Protein Biochemistry (IBP), Italian National Research Council (CNR), Napoli, Italy
| | - Namrata Ravi Iyengar
- Institute of Protein Biochemistry (IBP), Italian National Research Council (CNR), Napoli, Italy
| | - Riccardo Rizzo
- Institute of Protein Biochemistry (IBP), Italian National Research Council (CNR), Napoli, Italy
| | - Antonella di Campli
- Institute of Protein Biochemistry (IBP), Italian National Research Council (CNR), Napoli, Italy; Department of Medical, Oral and Biotechnological Sciences and CeSI-MeT, Center for Research on Ageing and Translational Medicine, "G. d'Annunzio" University of Chieti-Pescara, Chieti, Italy
| | - Rosaria Di Martino
- Institute of Protein Biochemistry (IBP), Italian National Research Council (CNR), Napoli, Italy
| | - Matteo Lo Monte
- Institute of Protein Biochemistry (IBP), Italian National Research Council (CNR), Napoli, Italy
| | - Andrea R Beccari
- Institute of Protein Biochemistry (IBP), Italian National Research Council (CNR), Napoli, Italy; Dompé Farmaceutici SpA, Milan, Italy
| | - Amol Yerudkar
- Department of Engineering, Universitá degli Studi del Sannio, Benevento, Italy
| | - Carmen Del Vecchio
- Department of Engineering, Universitá degli Studi del Sannio, Benevento, Italy
| | - Luigi Glielmo
- Department of Engineering, Universitá degli Studi del Sannio, Benevento, Italy
| | - Gabriele Turacchio
- Institute of Protein Biochemistry (IBP), Italian National Research Council (CNR), Napoli, Italy
| | - Marinella Pirozzi
- Institute of Protein Biochemistry (IBP), Italian National Research Council (CNR), Napoli, Italy
| | - Sang Geon Kim
- College of Pharmacy and Research Institute of Pharmaceutical Sciences, Seoul National University, Seoul, South Korea
| | - Petra Henklein
- Institut fur Biochemie, Charite Universitätsmedizin, Berlin, Germany
| | - Jorge Cancino
- Centro de Biología Celular y Biomedicina (CEBICEM), Facultad de Medicina y Ciencia, Universidad San Sebastián, Lota 2465, Santiago 7510157, Chile
| | | | - Dario Diviani
- Université de Lausanne, Département de Pharmacologie et Toxicologie, Rue du Bugnon 27, 1011 Lausanne, Switzerland
| | - Francesca Fanelli
- Department of Life Sciences, University of Modena and Reggio Emilia, Modena, Italy
| | - Michele Sallese
- Department of Medical, Oral and Biotechnological Sciences and CeSI-MeT, Center for Research on Ageing and Translational Medicine, "G. d'Annunzio" University of Chieti-Pescara, Chieti, Italy
| | - Alberto Luini
- Institute of Protein Biochemistry (IBP), Italian National Research Council (CNR), Napoli, Italy.
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13
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Zhang H, Nielsen AL, Strømgaard K. Recent achievements in developing selective Gqinhibitors. Med Res Rev 2019; 40:135-157. [DOI: 10.1002/med.21598] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2019] [Revised: 04/09/2019] [Accepted: 04/26/2019] [Indexed: 02/06/2023]
Affiliation(s)
- Hang Zhang
- Key Laboratory of Advanced Drug Preparation Technologies, Ministry of Education, Co‐innovation Center of Henan Province for New Drug R&D and Preclinical Safety, and School of Pharmaceutical SciencesZhengzhou UniversityZhengzhou Henan China
| | - Alexander L. Nielsen
- Department of Drug Design and Pharmacology, Center for BiopharmaceuticalsUniversity of CopenhagenCopenhagen Denmark
| | - Kristian Strømgaard
- Department of Drug Design and Pharmacology, Center for BiopharmaceuticalsUniversity of CopenhagenCopenhagen Denmark
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14
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Maeda S, Koehl A, Matile H, Hu H, Hilger D, Schertler GFX, Manglik A, Skiniotis G, Dawson RJP, Kobilka BK. Development of an antibody fragment that stabilizes GPCR/G-protein complexes. Nat Commun 2018; 9:3712. [PMID: 30213947 PMCID: PMC6137068 DOI: 10.1038/s41467-018-06002-w] [Citation(s) in RCA: 133] [Impact Index Per Article: 22.2] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2018] [Accepted: 07/25/2018] [Indexed: 11/10/2022] Open
Abstract
Single-particle cryo-electron microscopy (cryo-EM) has recently enabled high-resolution structure determination of numerous biological macromolecular complexes. Despite this progress, the application of high-resolution cryo-EM to G protein coupled receptors (GPCRs) in complex with heterotrimeric G proteins remains challenging, owning to both the relative small size and the limited stability of these assemblies. Here we describe the development of antibody fragments that bind and stabilize GPCR-G protein complexes for the application of high-resolution cryo-EM. One antibody in particular, mAb16, stabilizes GPCR/G-protein complexes by recognizing an interface between Gα and Gβγ subunits in the heterotrimer, and confers resistance to GTPγS-triggered dissociation. The unique recognition mode of this antibody makes it possible to transfer its binding and stabilizing effect to other G-protein subtypes through minimal protein engineering. This antibody fragment is thus a broadly applicable tool for structural studies of GPCR/G-protein complexes. The determination of high resolution structures of G protein coupled receptors (GPCRs) in complex with heterotrimeric G proteins is challenging. Here authors develop an antibody fragment, mAB16, which stabilizes GPCR/G-protein complexes and facilitates the application of high resolution cryo-EM.
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Affiliation(s)
- Shoji Maeda
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, 279 Campus Drive, Stanford, CA, 94305, USA
| | - Antoine Koehl
- Department of Structural Biology, Stanford University School of Medicine, 279 Campus Drive, Stanford, CA, 94305, USA
| | - Hugues Matile
- Roche Pharma Research and Early Development, Therapeutic Modalities, Roche Innovation Center Basel, F.Hoffmann-La Roche Ltd, Grenzacherstrasse 124, 4070, Basel, Switzerland
| | - Hongli Hu
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, 279 Campus Drive, Stanford, CA, 94305, USA.,Department of Structural Biology, Stanford University School of Medicine, 279 Campus Drive, Stanford, CA, 94305, USA
| | - Daniel Hilger
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, 279 Campus Drive, Stanford, CA, 94305, USA
| | - Gebhard F X Schertler
- Laboratory of Biomolecular Research, Paul Scherrer Institute, 5232, Villigen, Switzerland
| | - Aashish Manglik
- Department of Pharmaceutical Chemistry, University of California San Francisco, 1700 4th Street, San Francisco, CA, 94143, USA.,Department of Anesthesia and Perioperative Care, University of California San Francisco, 1700 4th Street, San Francisco, CA, 94143, USA
| | - Georgios Skiniotis
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, 279 Campus Drive, Stanford, CA, 94305, USA.,Department of Structural Biology, Stanford University School of Medicine, 279 Campus Drive, Stanford, CA, 94305, USA
| | - Roger J P Dawson
- Roche Pharma Research and Early Development, Therapeutic Modalities, Roche Innovation Center Basel, F.Hoffmann-La Roche Ltd, Grenzacherstrasse 124, 4070, Basel, Switzerland.
| | - Brian K Kobilka
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, 279 Campus Drive, Stanford, CA, 94305, USA.
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15
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Mastop M, Reinhard NR, Zuconelli CR, Terwey F, Gadella TWJ, van Unen J, Adjobo-Hermans MJW, Goedhart J. A FRET-based biosensor for measuring Gα13 activation in single cells. PLoS One 2018; 13:e0193705. [PMID: 29505611 PMCID: PMC5837189 DOI: 10.1371/journal.pone.0193705] [Citation(s) in RCA: 14] [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: 11/29/2017] [Accepted: 02/19/2018] [Indexed: 12/22/2022] Open
Abstract
Förster Resonance Energy Transfer (FRET) provides a way to directly observe the activation of heterotrimeric G-proteins by G-protein coupled receptors (GPCRs). To this end, FRET based biosensors are made, employing heterotrimeric G-protein subunits tagged with fluorescent proteins. These FRET based biosensors complement existing, indirect, ways to observe GPCR activation. Here we report on the insertion of mTurquoise2 at several sites in the human Gα13 subunit, aiming to develop a FRET-based Gα13 activation biosensor. Three fluorescently tagged Gα13 variants were found to be functional based on i) plasma membrane localization and ii) ability to recruit p115-RhoGEF upon activation of the LPA2 receptor. The tagged Gα13 subunits were used as FRET donor and combined with cp173Venus fused to the Gγ2 subunit, as the acceptor. We constructed Gα13 biosensors by generating a single plasmid that produces Gα13-mTurquoise2, Gβ1 and cp173Venus-Gγ2. The Gα13 activation biosensors showed a rapid and robust response when used in primary human endothelial cells that were exposed to thrombin, triggering endogenous protease activated receptors (PARs). This response was efficiently inhibited by the RGS domain of p115-RhoGEF and from the biosensor data we inferred that this is due to GAP activity. Finally, we demonstrated that the Gα13 sensor can be used to dissect heterotrimeric G-protein coupling efficiency in single living cells. We conclude that the Gα13 biosensor is a valuable tool for live-cell measurements that probe spatiotemporal aspects of Gα13 activation.
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Affiliation(s)
- Marieke Mastop
- Swammerdam Institute for Life Sciences, Section of Molecular Cytology, van Leeuwenhoek Centre for Advanced Microscopy, University of Amsterdam, Amsterdam, The Netherlands
| | - Nathalie R. Reinhard
- Swammerdam Institute for Life Sciences, Section of Molecular Cytology, van Leeuwenhoek Centre for Advanced Microscopy, University of Amsterdam, Amsterdam, The Netherlands
| | - Cristiane R. Zuconelli
- Department of Biochemistry, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Fenna Terwey
- Swammerdam Institute for Life Sciences, Section of Molecular Cytology, van Leeuwenhoek Centre for Advanced Microscopy, University of Amsterdam, Amsterdam, The Netherlands
| | - Theodorus W. J. Gadella
- Swammerdam Institute for Life Sciences, Section of Molecular Cytology, van Leeuwenhoek Centre for Advanced Microscopy, University of Amsterdam, Amsterdam, The Netherlands
| | - Jakobus van Unen
- Swammerdam Institute for Life Sciences, Section of Molecular Cytology, van Leeuwenhoek Centre for Advanced Microscopy, University of Amsterdam, Amsterdam, The Netherlands
| | - Merel J. W. Adjobo-Hermans
- Department of Biochemistry, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Joachim Goedhart
- Swammerdam Institute for Life Sciences, Section of Molecular Cytology, van Leeuwenhoek Centre for Advanced Microscopy, University of Amsterdam, Amsterdam, The Netherlands
- * E-mail:
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16
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Morimoto N, Mutai H, Namba K, Kaneko H, Kosaki R, Matsunaga T. Homozygous EDNRB mutation in a patient with Waardenburg syndrome type 1. Auris Nasus Larynx 2017; 45:222-226. [PMID: 28502583 DOI: 10.1016/j.anl.2017.03.022] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2016] [Revised: 03/02/2017] [Accepted: 03/23/2017] [Indexed: 11/28/2022]
Abstract
OBJECTIVE To examine and expand the genetic spectrum of Waardenburg syndrome type 1 (WS1). METHODS Clinical features related to Waardenburg syndrome (WS) were examined in a five-year old patient. Mutation analysis of genes related to WS was performed in the proband and her parents. Molecular modeling of EDNRB and the p.R319W mutant was conducted to predict the pathogenicity of the mutation. RESULTS The proband showed sensorineural hearing loss, heterochromia iridis, and dystopia canthorum, fulfilling the clinical criteria of WS1. Genetic analyses revealed that the proband had no mutation in PAX3 which has been known as the cause of WS1, but had a homozygous missense mutation (p.R319W) in endothelin receptor type B (EDNRB) gene. The asymptomatic parents had the mutation in a heterozygote state. This mutation has been previously reported in a heterozygous state in a patient with Hirschsprung's disease unaccompanied by WS, but the patient and her parents did not show any symptoms in gastrointestinal tract. Molecular modeling of EDNRB with the p.R319W mutation demonstrated reduction of the positively charged surface area in this region, which might reduce binding ability of EDNRB to G protein and lead to abnormal signal transduction underlying the WS phenotype. CONCLUSIONS Our findings suggested that autosomal recessive mutation in EDNRB may underlie a part of WS1 with the current diagnostic criteria, and supported that Hirschsprung's disease is a multifactorial genetic disease which requires additional factors. Further molecular analysis is necessary to elucidate the gene interaction and to reappraise the current WS classification.
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Affiliation(s)
- Noriko Morimoto
- Division of Otolaryngology, National Center for Child Health and Development, 2-10-1 Ohkura, Setagaya, Tokyo 157-8535, Japan
| | - Hideki Mutai
- Division of Hearing and Balance Research, National Institute of Sensory Organ, National Hospital Organization Tokyo Medical Center, 2-5-1 Higashigaoka, Meguro, Tokyo 152-8902, Japan
| | - Kazunori Namba
- Division of Hearing and Balance Research, National Institute of Sensory Organ, National Hospital Organization Tokyo Medical Center, 2-5-1 Higashigaoka, Meguro, Tokyo 152-8902, Japan
| | - Hiroki Kaneko
- The Institute of Natural Sciences, College of Humanities and Sciences, Nihon University, 3-25-40 Sakurajosui, Segataya, Tokyo 156-8550, Japan
| | - Rika Kosaki
- Division of Medical Genetics, National Center for Child Health and Development, 2-10-1 Ohkura, Setagaya, Tokyo 157-8535, Japan
| | - Tatsuo Matsunaga
- Division of Hearing and Balance Research, National Institute of Sensory Organ, National Hospital Organization Tokyo Medical Center, 2-5-1 Higashigaoka, Meguro, Tokyo 152-8902, Japan; Medical Genetics Center, National Hospital Organization Tokyo Medical Center, 2-5-1 Higashigaoka, Meguro, Tokyo 152-8902, Japan.
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17
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Bodmann EL, Krett AL, Bünemann M. Potentiation of receptor responses induced by prolonged binding of Gα 13 and leukemia-associated RhoGEF. FASEB J 2017; 31:3663-3676. [PMID: 28465324 DOI: 10.1096/fj.201700026r] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2017] [Accepted: 04/17/2017] [Indexed: 12/29/2022]
Abstract
Diverse cellular functions are controlled by RhoA-GTPases, which are activated by trimeric G proteins via RhoGEFs, among others. In this study, we focused on the signaling from GPCRs to RhoA via Gα13 and leukemia-associated RhoGEF (LARG). The activation of Gα13 was elucidated in living cells with high temporal and spatial resolution by means of FRET. The inactivation after agonist withdrawal occurred in the same range (t1/2 = 25.3 ± 2.2 s; mean ± sem; n = 22) as described for other Gα proteins. The interaction of Gα13 and LARG and the thereby-induced LARG translocation to the plasma membrane were at least 1 order of magnitude more stable after agonist withdrawal, exceeding Gα13 deactivation in the absence of LARG several fold. Consequently, we observed an almost 100-fold higher agonist sensitivity of the Gα13 LARG interaction compared to the Gα13 activation in the absence of LARG.-Bodmann, E.-L., Krett, A.-L., Bünemann, M. Potentiation of receptor responses induced by prolonged binding of Gα13 and leukemia-associated RhoGEF.
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Affiliation(s)
- Eva-Lisa Bodmann
- Department of Pharmacology and Clinical Pharmacy, Philipps University of Marburg, Marburg, Germany
| | - Anna-Lena Krett
- Department of Pharmacology and Clinical Pharmacy, Philipps University of Marburg, Marburg, Germany
| | - Moritz Bünemann
- Department of Pharmacology and Clinical Pharmacy, Philipps University of Marburg, Marburg, Germany
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18
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Mechanism of the intrinsic arginine finger in heterotrimeric G proteins. Proc Natl Acad Sci U S A 2016; 113:E8041-E8050. [PMID: 27911799 DOI: 10.1073/pnas.1612394113] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Heterotrimeric G proteins are crucial molecular switches that maintain a large number of physiological processes in cells. The signal is encoded into surface alterations of the Gα subunit that carries GTP in its active state and GDP in its inactive state. The ability of the Gα subunit to hydrolyze GTP is essential for signal termination. Regulator of G protein signaling (RGS) proteins accelerates this process. A key player in this catalyzed reaction is an arginine residue, Arg178 in Gαi1, which is already an intrinsic part of the catalytic center in Gα in contrast to small GTPases, at which the corresponding GTPase-activating protein (GAP) provides the arginine "finger." We applied time-resolved FTIR spectroscopy in combination with isotopic labeling and site-directed mutagenesis to reveal the molecular mechanism, especially of the role of Arg178 in the intrinsic Gαi1 mechanism and the RGS4-catalyzed mechanism. Complementary biomolecular simulations (molecular mechanics with molecular dynamics and coupled quantum mechanics/molecular mechanics) were performed. Our findings show that Arg178 is bound to γ-GTP for the intrinsic Gαi1 mechanism and pushed toward a bidentate α-γ-GTP coordination for the Gαi1·RGS4 mechanism. This movement induces a charge shift toward β-GTP, increases the planarity of γ-GTP, and thereby catalyzes the hydrolysis.
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19
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Mahoney JP, Sunahara RK. Mechanistic insights into GPCR-G protein interactions. Curr Opin Struct Biol 2016; 41:247-254. [PMID: 27871057 DOI: 10.1016/j.sbi.2016.11.005] [Citation(s) in RCA: 79] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2016] [Revised: 10/24/2016] [Accepted: 11/04/2016] [Indexed: 01/24/2023]
Abstract
G protein-coupled receptors (GPCRs) respond to extracellular stimuli and interact with several intracellular binding partners to elicit cellular responses, including heterotrimeric G proteins. Recent structural and biophysical studies have highlighted the dynamic nature of GPCRs and G proteins and have identified specific conformational changes important for receptor-mediated nucleotide exchange on Gα. While domain separation within Gα is necessary for GDP release, opening the inter-domain interface is insufficient to stimulate nucleotide exchange. Rather, an activated receptor promotes GDP release by allosterically disrupting the nucleotide-binding site via interactions with the Gα N-termini and C-termini. Highlighting the allosteric nature of GPCRs, recent studies suggest that agonist binding alone poorly stabilizes an active conformation of several receptors. Rather, full stabilization of the receptor in an active state requires formation of the agonist-receptor-G protein ternary complex. In turn, nucleotide-free Gα is able to stabilize conformational changes around the receptor's agonist-binding site to enhance agonist affinity.
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Affiliation(s)
- Jacob P Mahoney
- Department of Pharmacology, University of Michigan Medical School, Ann Arbor, MI 48109, United States
| | - Roger K Sunahara
- Department of Pharmacology, University of California at San Diego, La Jolla, CA 92093, United States.
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20
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Schiemer J, Bohm A, Lin L, Merrill-Skoloff G, Flaumenhaft R, Huang JS, Le Breton GC, Chishti AH. Gα13 Switch Region 2 Relieves Talin Autoinhibition to Activate αIIbβ3 Integrin. J Biol Chem 2016; 291:26598-26612. [PMID: 27803165 DOI: 10.1074/jbc.m116.747279] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2016] [Revised: 10/28/2016] [Indexed: 11/06/2022] Open
Abstract
Integrins function as bi-directional signaling transducers that regulate cell-cell and cell-matrix signals across the membrane. A key modulator of integrin activation is talin, a large cytoskeletal protein that exists in an autoinhibited state in quiescent cells. Talin is a large 235-kDa protein composed of an N-terminal 45-kDa FERM (4.1, ezrin-, radixin-, and moesin-related protein) domain, also known as the talin head domain, and a series of helical bundles known as the rod domain. The talin head domain consists of four distinct lobes designated as F0-F3. Integrin binding and activation are mediated through the F3 region, a critically regulated domain in talin. Regulation of the F3 lobe is accomplished through autoinhibition via anti-parallel dimerization. In the anti-parallel dimerization model, the rod domain region of one talin molecule binds to the F3 lobe on an adjacent talin molecule, thus achieving the state of autoinhibition. Platelet functionality requires integrin activation for adherence and thrombus formation, and thus regulation of talin presents a critical node where pharmacological intervention is possible. A major mechanism of integrin activation in platelets is through heterotrimeric G protein signaling regulating hemostasis and thrombosis. Here, we provide evidence that switch region 2 (SR2) of the ubiquitously expressed G protein (Gα13) directly interacts with talin, relieves its state of autoinhibition, and triggers integrin activation. Biochemical analysis of Gα13 shows SR2 binds directly to the F3 lobe of talin's head domain and competes with the rod domain for binding. Intramolecular FRET analysis shows Gα13 can relieve autoinhibition in a cellular milieu. Finally, a myristoylated SR2 peptide shows demonstrable decrease in thrombosis in vivo Altogether, we present a mechanistic basis for the regulation of talin through Gα13.
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Affiliation(s)
- James Schiemer
- From the Department of Developmental, Molecular, and Chemical Biology.,Sackler School of Graduate Biomedical Sciences, Programs in Cellular and Molecular Physiology
| | - Andrew Bohm
- From the Department of Developmental, Molecular, and Chemical Biology
| | - Li Lin
- From the Department of Developmental, Molecular, and Chemical Biology.,Pharmacology and Experimental Therapeutics and Molecular Microbiology, Tufts University School of Medicine, Boston, Massachusetts 02111
| | - Glenn Merrill-Skoloff
- the Division of Hemostasis and Thrombosis, Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts 02115
| | - Robert Flaumenhaft
- the Division of Hemostasis and Thrombosis, Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts 02115
| | - Jin-Sheng Huang
- the Research Resources Center, Protein Research Laboratory, University of Illinois at Chicago, Chicago, Illinois 60612, and
| | - Guy C Le Breton
- the Department of Pharmacology, College of Medicine, University of Illinois at Chicago, Chicago, Illinois 60612
| | - Athar H Chishti
- From the Department of Developmental, Molecular, and Chemical Biology, .,Sackler School of Graduate Biomedical Sciences, Programs in Cellular and Molecular Physiology.,Pharmacology and Experimental Therapeutics and Molecular Microbiology, Tufts University School of Medicine, Boston, Massachusetts 02111
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21
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Liu P, Jia MZ, Zhou XE, De Waal PW, Dickson BM, Liu B, Hou L, Yin YT, Kang YY, Shi Y, Melcher K, Xu HE, Jiang Y. The structural basis of the dominant negative phenotype of the Gαi1β1γ2 G203A/A326S heterotrimer. Acta Pharmacol Sin 2016; 37:1259-72. [PMID: 27498775 PMCID: PMC5022103 DOI: 10.1038/aps.2016.69] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2016] [Accepted: 06/08/2016] [Indexed: 12/13/2022] Open
Abstract
Aim: Dominant negative mutant G proteins have provided critical insight into the mechanisms of G protein-coupled receptor (GPCR) signaling, but the mechanisms underlying the dominant negative characteristics are not completely understood. The aim of this study was to determine the structure of the dominant negative Gαi1β1γ2 G203A/A326S complex (Gi-DN) and to reveal the structural basis of the mutation-induced phenotype of Gαi1β1γ2. Methods: The three subunits of the Gi-DN complex were co-expressed with a baculovirus expression system. The Gi-DN heterotrimer was purified, and the structure of its complex with GDP was determined through X-ray crystallography. Results: The Gi-DN heterotrimer structure revealed a dual mechanism underlying the dominant negative characteristics. The mutations weakened the hydrogen bonding network between GDP/GTP and the binding pocket residues, and increased the interactions in the Gα-Gβγ interface. Concomitantly, the Gi-DN heterotrimer adopted a conformation, in which the C-terminus of Gαi and the N-termini of both the Gβ and Gγ subunits were more similar to the GPCR-bound state compared with the wild type complex. From these structural observations, two additional mutations (T48F and D272F) were designed that completely abolish the GDP binding of the Gi-DN heterotrimer. Conclusion: Overall, the results suggest that the mutations impede guanine nucleotide binding and Gα-Gβγ protein dissociation and favor the formation of the G protein/GPCR complex, thus blocking signal propagation. In addition, the structure provides a rationale for the design of other mutations that cause dominant negative effects in the G protein, as exemplified by the T48F and D272F mutations.
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22
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Sprang SR. Invited review: Activation of G proteins by GTP and the mechanism of Gα-catalyzed GTP hydrolysis. Biopolymers 2016; 105:449-62. [PMID: 26996924 PMCID: PMC5319639 DOI: 10.1002/bip.22836] [Citation(s) in RCA: 50] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2016] [Revised: 03/11/2016] [Accepted: 03/17/2016] [Indexed: 02/02/2023]
Abstract
This review addresses the regulatory consequences of the binding of GTP to the alpha subunits (Gα) of heterotrimeric G proteins, the reaction mechanism of GTP hydrolysis catalyzed by Gα and the means by which GTPase activating proteins (GAPs) stimulate the GTPase activity of Gα. The high energy of GTP binding is used to restrain and stabilize the conformation of the Gα switch segments, particularly switch II, to afford stable complementary to the surfaces of Gα effectors, while excluding interaction with Gβγ, the regulatory binding partner of GDP-bound Gα. Upon GTP hydrolysis, the energy of these conformational restraints is dissipated and the two switch segments, particularly switch II, become flexible and are able to adopt a conformation suitable for tight binding to Gβγ. Catalytic site pre-organization presents a significant activation energy barrier to Gα GTPase activity. The glutamine residue near the N-terminus of switch II (Glncat ) must adopt a conformation in which it orients and stabilizes the γ phosphate and the water nucleophile for an in-line attack. The transition state is probably loose with dissociative character; phosphoryl transfer may be concerted. The catalytic arginine in switch I (Argcat ), together with amide hydrogen bonds from the phosphate binding loop, stabilize charge at the β-γ bridge oxygen of the leaving group. GAPs that harbor "regulator of protein signaling" (RGS) domains, or structurally unrelated domains within G protein effectors that function as GAPs, accelerate catalysis by stabilizing the pre-transition state for Gα-catalyzed GTP hydrolysis, primarily by restraining Argcat and Glncat to their catalytic conformations. © 2016 Wiley Periodicals, Inc. Biopolymers 105: 449-462, 2016.
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Affiliation(s)
- Stephen R. Sprang
- Center for Biomolecular Structure and Dynamics, Division of Biological Sciences, University of Montana, 32 Campus Drive, Missoula, MT 59812, Telephone: (406) 243-6028, Fax: (406) 243-6024,
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Montgomery ER, Temple BRS, Peters KA, Tolbert CE, Booker BK, Martin JW, Hamilton TP, Tagliatela AC, Smolski WC, Rogers SL, Jones AM, Meigs TE. Gα12 structural determinants of Hsp90 interaction are necessary for serum response element-mediated transcriptional activation. Mol Pharmacol 2014; 85:586-97. [PMID: 24435554 PMCID: PMC3965892 DOI: 10.1124/mol.113.088443] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2013] [Accepted: 01/16/2014] [Indexed: 12/31/2022] Open
Abstract
The G12/13 class of heterotrimeric G proteins, comprising the α-subunits Gα12 and Gα13, regulates multiple aspects of cellular behavior, including proliferation and cytoskeletal rearrangements. Although guanine nucleotide exchange factors for the monomeric G protein Rho (RhoGEFs) are well characterized as effectors of this G protein class, a variety of other downstream targets has been reported. To identify Gα12 determinants that mediate specific protein interactions, we used a structural and evolutionary comparison between the G12/13, Gs, Gi, and Gq classes to identify "class-distinctive" residues in Gα12 and Gα13. Mutation of these residues in Gα12 to their deduced ancestral forms revealed a subset necessary for activation of serum response element (SRE)-mediated transcription, a G12/13-stimulated pathway implicated in cell proliferative signaling. Unexpectedly, this subset of Gα12 mutants showed impaired binding to heat-shock protein 90 (Hsp90) while retaining binding to RhoGEFs. Corresponding mutants of Gα13 exhibited robust SRE activation, suggesting a Gα12-specific mechanism, and inhibition of Hsp90 by geldanamycin or small interfering RNA-mediated lowering of Hsp90 levels resulted in greater downregulation of Gα12 than Gα13 signaling in SRE activation experiments. Furthermore, the Drosophila G12/13 homolog Concertina was unable to signal to SRE in mammalian cells, and Gα12:Concertina chimeras revealed Gα12-specific determinants of SRE activation within the switch regions and a C-terminal region. These findings identify Gα12 determinants of SRE activation, implicate Gα12:Hsp90 interaction in this signaling mechanism, and illuminate structural features that arose during evolution of Gα12 and Gα13 to allow bifurcated mechanisms of signaling to a common cell proliferative pathway.
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Affiliation(s)
- Ellyn R Montgomery
- Department of Biology, University of North Carolina at Asheville, Asheville, North Carolina (E.R.M., B.K.B., J.W.M., T.P.H., A.C.T., W.C.S., T.E.M.); Departments of Biology (K.A.P., S.L.R., A.M.J.), Biochemistry and Biophysics (B.R.S.T.), Cell Biology and Physiology (C.E.T.), and Pharmacology (A.M.J.), R. L. Juliano Structural Bioinformatics Core Facility (B.R.S.T.), and Carolina Center for Genome Sciences (S.L.R.), University of North Carolina, and the Lineberger Comprehensive Cancer Center, (S.L.R., T.E.M.), Chapel Hill, North Carolina
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24
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Gan X, Wang C, Patel M, Kreutz B, Zhou M, Kozasa T, Wu D. Different Raf protein kinases mediate different signaling pathways to stimulate E3 ligase RFFL gene expression in cell migration regulation. J Biol Chem 2013; 288:33978-33984. [PMID: 24114843 DOI: 10.1074/jbc.m113.477406] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
We previously characterized a Gα12-specific signaling pathway that stimulates the transcription of the E3 ligase RFFL via the protein kinase ARAF and ERK. This pathway leads to persistent PKC activation and is important for sustaining fibroblast migration. However, questions remain regarding how Gα12 specifically activates ARAF, which transcription factor is involved in Gα12-mediated RFFL expression, and whether RFFL is important for cell migration stimulated by other signaling mechanisms that can activate ERK. In this study, we show that replacement of the Gα12 residue Arg-264 with Gln, which is the corresponding Gα13 residue, abrogates the ability of Gα12 to interact with or activate ARAF. We also show that Gα12 can no longer interact with and activate an ARAF mutant with its C-terminal sequence downstream of the kinase domain being replaced with the corresponding CRAF sequence. These results explain why Gα12, but not Gα13, specifically activates ARAF but not CRAF. Together with our finding that recombinant Gα12 is sufficient for stimulating the kinase activity of ARAF, this study reveals an ARAF activation mechanism that is different from that of CRAF. In addition, we show that this Gα12-ARAF-ERK pathway stimulates RFFL transcription through the transcription factor c-Myc. We further demonstrate that EGF, which signals through CRAF, and an activated BRAF mutant also activate PKC and stimulate cell migration through up-regulating RFFL expression. Thus, RFFL-mediated PKC activation has a broad significance in cell migration regulation.
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Affiliation(s)
- Xiaoqing Gan
- Department of Pharmacology and Program in Vascular Biology and Therapeutics, Yale School of Medicine, New Haven, Connecticut 06520
| | - Chen Wang
- Department of Pharmacology and Program in Vascular Biology and Therapeutics, Yale School of Medicine, New Haven, Connecticut 06520
| | - Maulik Patel
- Department of Pharmacology, University of Illinois at Chicago, Chicago, Illinois 60612
| | - Barry Kreutz
- Department of Pharmacology, University of Illinois at Chicago, Chicago, Illinois 60612
| | - Maggie Zhou
- Department of Pharmacology and Program in Vascular Biology and Therapeutics, Yale School of Medicine, New Haven, Connecticut 06520
| | - Tohru Kozasa
- Department of Pharmacology, University of Illinois at Chicago, Chicago, Illinois 60612; Research Center for Advanced Science and Technology, University of Tokyo, Tokyo 153, Japan
| | - Dianqing Wu
- Department of Pharmacology and Program in Vascular Biology and Therapeutics, Yale School of Medicine, New Haven, Connecticut 06520.
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25
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Moreira IS. Structural features of the G-protein/GPCR interactions. Biochim Biophys Acta Gen Subj 2013; 1840:16-33. [PMID: 24016604 DOI: 10.1016/j.bbagen.2013.08.027] [Citation(s) in RCA: 75] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2013] [Revised: 08/27/2013] [Accepted: 08/28/2013] [Indexed: 01/07/2023]
Abstract
BACKGROUND The details of the functional interaction between G proteins and the G protein coupled receptors (GPCRs) have long been subjected to extensive investigations with structural and functional assays and a large number of computational studies. SCOPE OF REVIEW The nature and sites of interaction in the G-protein/GPCR complexes, and the specificities of these interactions selecting coupling partners among the large number of families of GPCRs and G protein forms, are still poorly defined. MAJOR CONCLUSIONS Many of the contact sites between the two proteins in specific complexes have been identified, but the three dimensional molecular architecture of a receptor-Gα interface is only known for one pair. Consequently, many fundamental questions regarding this macromolecular assembly and its mechanism remain unanswered. GENERAL SIGNIFICANCE In the context of current structural data we review the structural details of the interfaces and recognition sites in complexes of sub-family A GPCRs with cognate G-proteins, with special emphasis on the consequences of activation on GPCR structure, the prevalence of preassembled GPCR/G-protein complexes, the key structural determinants for selective coupling and the possible involvement of GPCR oligomerization in this process.
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Affiliation(s)
- Irina S Moreira
- REQUIMTE/Departamento de Química e Bioquímica, Faculdade de Ciências da Universidade do Porto, Rua do Campo Alegre s/n, 4169-007 Porto, Portugal.
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26
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Ritchie BJ, Smolski WC, Montgomery ER, Fisher ES, Choi TY, Olson CM, Foster LA, Meigs TE. Determinants at the N- and C-termini of Gα12 required for activation of Rho-mediated signaling. J Mol Signal 2013; 8:3. [PMID: 23531275 PMCID: PMC3636079 DOI: 10.1186/1750-2187-8-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2013] [Accepted: 03/17/2013] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Heterotrimeric guanine nucleotide binding proteins of the G12/13 subfamily, which includes the α-subunits Gα12 and Gα13, stimulate the monomeric G protein RhoA through interaction with a distinct subset of Rho-specific guanine nucleotide exchange factors (RhoGEFs). The structural features that mediate interaction between Gα13 and RhoGEFs have been examined in crystallographic studies of the purified complex, whereas a Gα12:RhoGEF complex has not been reported. Several signaling responses and effector interactions appear unique to Gα12 or Gα13, despite their similarity in amino acid sequence. METHODS To comprehensively examine Gα12 for regions involved in RhoGEF interaction, we screened a panel of Gα12 cassette substitution mutants for binding to leukemia-associated RhoGEF (LARG) and for activation of serum response element mediated transcription. RESULTS We identified several cassette substitutions that disrupt Gα12 binding to LARG and the related p115RhoGEF. These Gα12 mutants also were impaired in activating serum response element mediated signaling, a Rho-dependent response. Most of these mutants matched corresponding regions of Gα13 reported to contact p115RhoGEF, but unexpectedly, several RhoGEF-uncoupling mutations were found within the N- and C-terminal regions of Gα12. Trypsin protection assays revealed several mutants in these regions as retaining conformational activation. In addition, charge substitutions near the Gα12 N-terminus selectively disrupted binding to LARG but not p115RhoGEF. CONCLUSIONS Several structural aspects of the Gα12:RhoGEF interface differ from the reported Gα13:RhoGEF complex, particularly determinants within the C-terminal α5 helix and structurally uncharacterized N-terminus of Gα12. Furthermore, key residues at the Gα12 N-terminus may confer selectivity for LARG as a downstream effector.
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Affiliation(s)
- Benjamin J Ritchie
- Department of Biology, University of North Carolina at Asheville, One University Heights, Asheville, NC 28804, USA.
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27
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Chen Z, Guo L, Hadas J, Gutowski S, Sprang SR, Sternweis PC. Activation of p115-RhoGEF requires direct association of Gα13 and the Dbl homology domain. J Biol Chem 2012; 287:25490-500. [PMID: 22661716 PMCID: PMC3408165 DOI: 10.1074/jbc.m111.333716] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2011] [Revised: 05/30/2012] [Indexed: 01/05/2023] Open
Abstract
RGS-containing RhoGEFs (RGS-RhoGEFs) represent a direct link between the G(12) class of heterotrimeric G proteins and the monomeric GTPases. In addition to the canonical Dbl homology (DH) and pleckstrin homology domains that carry out the guanine nucleotide exchange factor (GEF) activity toward RhoA, these RhoGEFs also possess RGS homology (RH) domains that interact with activated α subunits of G(12) and G(13). Although the GEF activity of p115-RhoGEF (p115), an RGS-RhoGEF, can be stimulated by Gα(13), the exact mechanism of the stimulation has remained unclear. Using combined studies with small angle x-ray scattering, biochemistry, and mutagenesis, we identify an additional binding site for activated Gα(13) in the DH domain of p115. Small angle x-ray scattering reveals that the helical domain of Gα(13) docks onto the DH domain, opposite to the surface of DH that binds RhoA. Mutation of a single tryptophan residue in the α3b helix of DH reduces binding to activated Gα(13) and ablates the stimulation of p115 by Gα(13). Complementary mutations at the predicted DH-binding site in the αB-αC loop of the helical domain of Gα(13) also affect stimulation of p115 by Gα(13). Although the GAP activity of p115 is not required for stimulation by Gα(13), two hydrophobic motifs in RH outside of the consensus RGS box are critical for this process. Therefore, the binding of Gα(13) to the RH domain facilitates direct association of Gα(13) to the DH domain to regulate its exchange activity. This study provides new insight into the mechanism of regulation of the RGS-RhoGEF and broadens our understanding of G protein signaling.
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Affiliation(s)
- Zhe Chen
- From the Departments of Biochemistry and
| | - Liang Guo
- BioCAT, Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois 60439, and
| | - Jana Hadas
- Pharmacology, The University of Texas Southwestern Medical Center at Dallas, Dallas, Texas 75390
| | - Stephen Gutowski
- Pharmacology, The University of Texas Southwestern Medical Center at Dallas, Dallas, Texas 75390
| | - Stephen R. Sprang
- Center for Biomolecular Structure and Dynamics, Division of Biological Sciences, University of Montana, Missoula, Montana 59812
| | - Paul C. Sternweis
- Pharmacology, The University of Texas Southwestern Medical Center at Dallas, Dallas, Texas 75390
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28
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Singh G, Ramachandran S, Cerione RA. A constitutively active Gα subunit provides insights into the mechanism of G protein activation. Biochemistry 2012; 51:3232-40. [PMID: 22448927 PMCID: PMC3620018 DOI: 10.1021/bi3001984] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
The activation of Gα subunits of heterotrimeric G proteins by G protein-coupled receptors (GPCRs) is a critical event underlying a variety of biological responses. Understanding how G proteins are activated will require structural and biochemical analyses of GPCRs complexed to their G protein partners, together with structure-function studies of Gα mutants that shed light on the different steps in the activation pathway. Previously, we reported that the substitution of a glycine for a proline at position 56 within the linker region connecting the helical and GTP-binding domains of a Gα chimera, designated αT*, yields a more readily exchangeable state for guanine nucleotides. Here we show that GDP-GTP exchange on αT*(G56P), in the presence of the light-activated GPCR, rhodopsin (R*), is less sensitive to the β1γ1 subunit complex than to wild-type αT*. We determined the X-ray crystal structure for the αT*(G56P) mutant and found that the G56P substitution leads to concerted changes that are transmitted to the conformationally sensitive switch regions, the α4-β6 loop, and the β6 strand. The α4-β6 loop has been proposed to be a GPCR contact site that signals to the TCAT motif and weakens the binding of the guanine ring of GDP, whereas the switch regions are the contact sites for the β1γ1 complex. Collectively, these biochemical and structural data lead us to suggest that αT*(G56P) may be adopting a conformation that is normally induced within Gα subunits by the combined actions of a GPCR and a Gβγ subunit complex during the G protein activation event.
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Affiliation(s)
| | | | - Richard A. Cerione
- To whom correspondence should be addressed: Department of Molecular Medicine, College of Veterinary Medicine, Cornell University, Ithaca, NY 14853-6401. Tel: (607) 253-3888. Fax: (607) 253-3659,
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29
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RIC8 is a guanine-nucleotide exchange factor for Galpha subunits that regulates growth and development in Neurospora crassa. Genetics 2011; 189:165-76. [PMID: 21750256 DOI: 10.1534/genetics.111.129270] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Heterotrimeric (αβγ) G proteins are crucial components of eukaryotic signal transduction pathways. G-protein-coupled receptors (GPCRs) act as guanine nucleotide exchange factors (GEFs) for Gα subunits. Recently, facilitated GDP/GTP exchange by non-GPCR GEFs, such as RIC8, has emerged as an important mechanism for Gα regulation in animals. RIC8 is present in animals and filamentous fungi, such as the model eukaryote Neurospora crassa, but is absent from the genomes of baker's yeast and plants. In Neurospora, deletion of ric8 leads to profound defects in growth and asexual and sexual development, similar to those observed for a mutant lacking the Gα genes gna-1 and gna-3. In addition, constitutively activated alleles of gna-1 and gna-3 rescue many defects of Δric8 mutants. Similar to reports in Drosophila, Neurospora Δric8 strains have greatly reduced levels of G-protein subunits. Effects on cAMP signaling are suggested by low levels of adenylyl cyclase protein in Δric8 mutants and suppression of Δric8 by a mutation in the protein kinase A regulatory subunit. RIC8 acts as a GEF for GNA-1 and GNA-3 in vitro, with the strongest effect on GNA-3. Our results support a role for RIC8 in regulating GNA-1 and GNA-3 in Neurospora.
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30
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Hajicek N, Kukimoto-Niino M, Mishima-Tsumagari C, Chow CR, Shirouzu M, Terada T, Patel M, Yokoyama S, Kozasa T. Identification of critical residues in G(alpha)13 for stimulation of p115RhoGEF activity and the structure of the G(alpha)13-p115RhoGEF regulator of G protein signaling homology (RH) domain complex. J Biol Chem 2011; 286:20625-36. [PMID: 21507947 PMCID: PMC3121507 DOI: 10.1074/jbc.m110.201392] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2010] [Revised: 04/08/2011] [Indexed: 01/28/2023] Open
Abstract
RH-RhoGEFs are a family of guanine nucleotide exchange factors that contain a regulator of G protein signaling homology (RH) domain. The heterotrimeric G protein Gα(13) stimulates the guanine nucleotide exchange factor (GEF) activity of RH-RhoGEFs, leading to activation of RhoA. The mechanism by which Gα(13) stimulates the GEF activity of RH-RhoGEFs, such as p115RhoGEF, has not yet been fully elucidated. Here, specific residues in Gα(13) that mediate activation of p115RhoGEF are identified. Mutation of these residues significantly impairs binding of Gα(13) to p115RhoGEF as well as stimulation of GEF activity. These data suggest that the exchange activity of p115RhoGEF is stimulated allosterically by Gα(13) and not through its interaction with a secondary binding site. A crystal structure of Gα(13) bound to the RH domain of p115RhoGEF is also presented, which differs from a previously crystallized complex with a Gα(13)-Gα(i1) chimera. Taken together, these data provide new insight into the mechanism by which p115RhoGEF is activated by Gα(13).
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Affiliation(s)
- Nicole Hajicek
- Department of Pharmacology, College of Medicine, University of Illinois, Chicago, Illinois 60612, USA
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31
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Iwanari H, Nakada-Nakura Y, Kusano-Arai O, Suzuki N, Kodama T, Sakihama T, Hamakubo T. A method of generating antibodies against exogenously administered self-antigen by manipulating CD4+CD25+ regulatory T cells. J Immunol Methods 2011; 369:108-14. [DOI: 10.1016/j.jim.2011.04.011] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2010] [Revised: 03/15/2011] [Accepted: 04/25/2011] [Indexed: 11/26/2022]
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32
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Louet M, Perahia D, Martinez J, Floquet N. A concerted mechanism for opening the GDP binding pocket and release of the nucleotide in hetero-trimeric G-proteins. J Mol Biol 2011; 411:298-312. [PMID: 21663745 DOI: 10.1016/j.jmb.2011.05.034] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2010] [Revised: 05/14/2011] [Accepted: 05/20/2011] [Indexed: 11/26/2022]
Abstract
G-protein hetero-trimers play a fundamental role in cell function. Their dynamic behavior at the atomic level remains to be understood. We have studied the Gi hetero-trimer through a combination of molecular dynamics simulations and normal mode analyses. We showed that these big proteins could undergo large-amplitude conformational changes, without any energy penalty and with an intrinsic dynamics centered on their GDP binding pocket. Among the computed collective motions, one of the modes (mode 17) was particularly able to significantly open both the base and the phosphate sides of the GDP binding pocket. This mode describing mainly a motion between the Ras-like and the helical domains of G(α) was in close agreement with some available X-ray data and with many other biochemical/biophysical observations including the kink of helix α5. The use of a new protocol, which allows extraction of the GDP ligand along the computed normal modes, supported that the exit of GDP was largely coupled to an opening motion along mode 17. We propose for the first time a "concerted mechanism" model in which the opening of the GDP pocket and the kink of the α5 helix occur concomitantly and favor GDP release from G(αβγ) complexes. This model is discussed in the context of the G-protein-coupled receptor/G-protein interaction close to the cell membrane.
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Affiliation(s)
- Maxime Louet
- Institut des Biomolécules Max Mousseron (IBMM), CNRS UMR5247, Université Montpellier 1-Université Montpellier 2, Faculté de Pharmacie, 15 Avenue Charles Flahault, BP 14491, 34093 Montpellier Cedex 05, France
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33
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Temple BRS, Jones CD, Jones AM. Evolution of a signaling nexus constrained by protein interfaces and conformational States. PLoS Comput Biol 2010; 6:e1000962. [PMID: 20976244 PMCID: PMC2954821 DOI: 10.1371/journal.pcbi.1000962] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2010] [Accepted: 09/17/2010] [Indexed: 01/03/2023] Open
Abstract
Heterotrimeric G proteins act as the physical nexus between numerous receptors that respond to extracellular signals and proteins that drive the cytoplasmic response. The Gα subunit of the G protein, in particular, is highly constrained due to its many interactions with proteins that control or react to its conformational state. Various organisms contain differing sets of Gα-interacting proteins, clearly indicating that shifts in sequence and associated Gα functionality were acquired over time. These numerous interactions constrained much of Gα evolution; yet Gα has diversified, through poorly understood processes, into several functionally specialized classes, each with a unique set of interacting proteins. Applying a synthetic sequence-based approach to mammalian Gα subunits, we established a set of seventy-five evolutionarily important class-distinctive residues, sites where a single Gα class is differentiated from the three other classes. We tested the hypothesis that shifts at these sites are important for class-specific functionality. Importantly, we mapped known and well-studied class-specific functionalities from all four mammalian classes to sixteen of our class-distinctive sites, validating the hypothesis. Our results show how unique functionality can evolve through the recruitment of residues that were ancestrally functional. We also studied acquisition of functionalities by following these evolutionarily important sites in non-mammalian organisms. Our results suggest that many class-distinctive sites were established early on in eukaryotic diversification and were critical for the establishment of new Gα classes, whereas others arose in punctuated bursts throughout metazoan evolution. These Gα class-distinctive residues are rational targets for future structural and functional studies.
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Affiliation(s)
- Brenda R S Temple
- R. L. Juliano Structural Bioinformatics Core Facility, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA.
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34
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Yu W, Ritchie BJ, Su X, Zhou J, Meigs TE, Denker BM. Identification of polycystin-1 and Gα12 binding regions necessary for regulation of apoptosis. Cell Signal 2010; 23:213-21. [PMID: 20837139 DOI: 10.1016/j.cellsig.2010.09.005] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2010] [Accepted: 09/05/2010] [Indexed: 10/19/2022]
Abstract
Most patients with autosomal dominant polycystic kidney disease (ADPKD) harbor mutations in PKD1, the gene for polycystin-1 (PC1), a transmembrane protein with a cytoplasmic C-terminus that interacts with numerous signaling molecules, including Gα12. The functions of PC1 and the mechanisms of cyst development leading to renal failure are complex. Recently, we reported that PC1 expression levels modulate activity of Gα12-stimulated apoptosis (Yu et al., J. Biol. Chem. 2010 285(14):10243-51). Herein, a mutational analysis of Gα12 and PC1 was undertaken to identify regions required for their interaction and ability to modulate apoptosis. A set of Gα12 mutations with systematic replacement of six amino acids with NAAIRS was tested for binding to the PC1 C-terminus in GST pulldowns. Additionally, a series of deletions within the PC1 C-terminus was examined for binding to Gα12. We identified 3 NAAIRS substitutions in Gα12 that completely abrogated binding, and identified a previously described 74 amino acid Gαi/o binding domain in the PC1 C-terminus as necessary for Gα12 interaction. The functional consequences of uncoupling PC1/Gα12 binding were studied in apoptosis assays utilizing HEK293 cells with inducible PC1 overexpression. Gα12 mutants deficient in PC1 binding were refractory to PC1 inhibition of Gα12-stimulated apoptosis. Likewise, deletion of the Gα12-interacting sequence from the PC1 cytoplasmic domain abrogated its inhibition of Gα12-stimulated apoptosis. Based on the crystal structure of Gα12, the PC1 interaction sites are likely to reside on exposed regions within the G protein helical domain. These structural details should facilitate the design of reagents to uncouple PC1/Gα12 signaling in ADPKD.
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Affiliation(s)
- Wanfeng Yu
- Renal Division Brigham and Women's Hospital, Boston, MA 02115, USA
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35
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Jernigan KK, Cselenyi CS, Thorne CA, Hanson AJ, Tahinci E, Hajicek N, Oldham WM, Lee LA, Hamm HE, Hepler JR, Kozasa T, Linder ME, Lee E. Gbetagamma activates GSK3 to promote LRP6-mediated beta-catenin transcriptional activity. Sci Signal 2010; 3:ra37. [PMID: 20460648 PMCID: PMC3088111 DOI: 10.1126/scisignal.2000647] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Evidence from Drosophila and cultured cell studies supports a role for heterotrimeric guanosine triphosphate-binding proteins (G proteins) in Wnt signaling. Wnt inhibits the degradation of the transcriptional regulator beta-catenin. We screened the alpha and betagamma subunits of major families of G proteins in a Xenopus egg extract system that reconstitutes beta-catenin degradation. We found that Galpha(o), Galpha(q), Galpha(i2), and Gbetagamma inhibited beta-catenin degradation. Gbeta(1)gamma(2) promoted the phosphorylation and activation of the Wnt co-receptor low-density lipoprotein receptor-related protein 6 (LRP6) by recruiting glycogen synthase kinase 3 (GSK3) to the membrane and enhancing its kinase activity. In both a reporter gene assay and an in vivo assay, c-betaARK (C-terminal domain of beta-adrenergic receptor kinase), an inhibitor of Gbetagamma, blocked LRP6 activity. Several components of the Wnt-beta-catenin pathway formed a complex: Gbeta(1)gamma(2), LRP6, GSK3, axin, and dishevelled. We propose that free Gbetagamma and Galpha subunits, released from activated G proteins, act cooperatively to inhibit beta-catenin degradation and activate beta-catenin-mediated transcription.
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Affiliation(s)
- Kristin K. Jernigan
- Department of Cell and Developmental Biology, Vanderbilt University Medical Center, Nashville, Tennessee, 37232, USA
| | - Christopher S. Cselenyi
- Department of Cell and Developmental Biology, Vanderbilt University Medical Center, Nashville, Tennessee, 37232, USA
| | - Curtis A. Thorne
- Department of Cell and Developmental Biology, Vanderbilt University Medical Center, Nashville, Tennessee, 37232, USA
| | - Alison J. Hanson
- Department of Cell and Developmental Biology, Vanderbilt University Medical Center, Nashville, Tennessee, 37232, USA
| | - Emilios Tahinci
- Department of Cell and Developmental Biology, Vanderbilt University Medical Center, Nashville, Tennessee, 37232, USA
| | - Nicole Hajicek
- Department of Pharmacology, University of Illinois, Chicago, Illinois, 60612, USA
- Research Center for Advanced Science and Technology, The University of Tokyo, 153- 8904, Japan
| | - William M. Oldham
- Department of Pharmacology, Vanderbilt University Medical Center, Nashville, Tennessee, 37232, USA
| | - Laura A. Lee
- Department of Cell and Developmental Biology, Vanderbilt University Medical Center, Nashville, Tennessee, 37232, USA
| | - Heidi E. Hamm
- Department of Pharmacology, Vanderbilt University Medical Center, Nashville, Tennessee, 37232, USA
| | - John R. Hepler
- Department of Pharmacology, Emory University School of Medicine, Atlanta, Georgia, 30322, USA
| | - Tohru Kozasa
- Department of Pharmacology, University of Illinois, Chicago, Illinois, 60612, USA
- Research Center for Advanced Science and Technology, The University of Tokyo, 153- 8904, Japan
| | - Maurine E. Linder
- Department of Molecular Medicine, Cornell University, Ithaca, New York, 14853, USA
| | - Ethan Lee
- Department of Cell and Developmental Biology, Vanderbilt University Medical Center, Nashville, Tennessee, 37232, USA
- Vanderbilt Ingram Cancer Center, Vanderbilt University, Nashville, Tennessee, 37232, USA
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36
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Kapoor N, Menon ST, Chauhan R, Sachdev P, Sakmar TP. Structural evidence for a sequential release mechanism for activation of heterotrimeric G proteins. J Mol Biol 2009; 393:882-97. [PMID: 19703466 DOI: 10.1016/j.jmb.2009.08.043] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2009] [Revised: 08/13/2009] [Accepted: 08/17/2009] [Indexed: 11/18/2022]
Abstract
Heptahelical G-protein (heterotrimeric guanine nucleotide-binding protein)-coupled receptors couple to heterotrimeric G proteins to relay extracellular signals to intracellular signaling networks, but the molecular mechanism underlying guanosine 5'-diphosphate (GDP) release by the G protein alpha-subunit is not well understood. Amino acid substitutions in the conserved alpha5 helix of G(i), which extends from the C-terminal region to the nucleotide-binding pocket, cause dramatic increases in basal (receptor-independent) GDP release rates. For example, mutant Galpha(i1)-T329A shows an 18-fold increase in basal GDP release rate and, when expressed in culture, it causes a significant decrease in forskolin-stimulated cAMP accumulation. The crystal structure of Galpha(i1)-T329A.GDP shows substantial conformational rearrangement of the switch I region and additional striking alterations of side chains lining the catalytic pocket that disrupt the Mg(+2) coordination sphere and dislodge bound Mg(+2). We propose a "sequential release" mechanism whereby a transient conformational change in the alpha5 helix alters switch I to induce GDP release. Interestingly, this mechanistic model for heterotrimeric G protein activation is similar to that suggested for the activation of the plant small G protein Rop4 by RopGEF8.
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Affiliation(s)
- Neeraj Kapoor
- Laboratory of Biochemistry and Molecular Biology, Rockefeller University, 1230 York Avenue, New York, NY 10065, USA
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37
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A conserved hydrophobic surface of the LARG pleckstrin homology domain is critical for RhoA activation in cells. Cell Signal 2009; 21:1569-78. [PMID: 19560536 DOI: 10.1016/j.cellsig.2009.06.003] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2009] [Accepted: 06/16/2009] [Indexed: 01/23/2023]
Abstract
Leukemia associated Rho guanine nucleotide exchange factor (LARG) activates RhoA in response to signals received by specific classes of cell surface receptors. The catalytic core of LARG is a Dbl homology (DH) domain whose activity is modulated by an adjacent pleckstrin homology (PH) domain. In this study, we used a transcriptional assay and confocal microscopy to examine the roles of several novel structural features of the LARG DH/PH domains, including a conserved and exposed hydrophobic patch on the PH domain that mediates protein-protein interactions in crystal structures of LARG and its close homolog PDZ-RhoGEF. Mutation of the hydrophobic patch has no effect on nucleotide exchange activity in vitro, but abolished the ability of LARG to activate RhoA and to induce stress fiber formation in cultured cells. The activity of these mutants could be rescued by fusion with exogenous membrane-targeting domains. However, because membrane recruitment by activated G alpha(13) subunits was not sufficient to rescue activity of a hydrophobic patch mutant, the LARG PH domain cannot solely contribute to membrane targeting. Instead, it seems likely that the domain is involved in regulatory interactions with other proteins near the membrane surface. We also show that the hydrophobic patch of the PH domain is likely important for the activity of all Lbc subfamily RhoGEFs.
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38
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Yao XJ, Vélez Ruiz G, Whorton MR, Rasmussen SGF, DeVree BT, Deupi X, Sunahara RK, Kobilka B. The effect of ligand efficacy on the formation and stability of a GPCR-G protein complex. Proc Natl Acad Sci U S A 2009; 106:9501-6. [PMID: 19470481 PMCID: PMC2685739 DOI: 10.1073/pnas.0811437106] [Citation(s) in RCA: 194] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2008] [Indexed: 12/13/2022] Open
Abstract
G protein-coupled receptors (GPCRs) mediate the majority of physiologic responses to hormones and neurotransmitters. However, many GPCRs exhibit varying degrees of agonist-independent G protein activation. This phenomenon is referred to as basal or constitutive activity. For many of these GPCRs, drugs classified as inverse agonists can suppress basal activity. There is a growing body of evidence that basal activity is physiologically relevant, and the ability of a drug to inhibit basal activity may influence its therapeutic properties. However, the molecular mechanism for basal activation and inhibition of basal activity by inverse agonists is poorly understood and difficult to study, because the basally active state is short-lived and represents a minor fraction of receptor conformations. Here, we investigate basal activation of the G protein Gs by the beta(2) adrenergic receptor (beta(2)AR) by using purified receptor reconstituted into recombinant HDL particles with a stoichiometric excess of Gs. The beta(2)AR is site-specifically labeled with a small, environmentally sensitive fluorophore enabling direct monitoring of agonist- and Gs-induced conformational changes. In the absence of an agonist, the beta(2)AR and Gs can be trapped in a complex by enzymatic depletion of guanine nucleotides. Formation of the complex is enhanced by the agonist isoproterenol, and it rapidly dissociates on exposure to concentrations of GTP and GDP found in the cytoplasm. The inverse agonist ICI prevents formation of the beta(2)AR-Gs complex, but has little effect on preformed complexes. These results provide insights into G protein-induced conformational changes in the beta(2)AR and the structural basis for ligand efficacy.
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Affiliation(s)
- Xiao Jie Yao
- Department of Molecular and Cellular Physiology, Stanford University Medical School Department of Chemistry, Stanford University, Stanford, CA 94305
| | - Gisselle Vélez Ruiz
- Department of Pharmacology, University of Michigan Medical School, 1301 Medical Sciences Research Building III, Ann Arbor, MI 48109; and
| | - Matthew R. Whorton
- Department of Pharmacology, University of Michigan Medical School, 1301 Medical Sciences Research Building III, Ann Arbor, MI 48109; and
| | - Søren G. F. Rasmussen
- Department of Molecular and Cellular Physiology, Stanford University Medical School Department of Chemistry, Stanford University, Stanford, CA 94305
| | - Brian T. DeVree
- Department of Pharmacology, University of Michigan Medical School, 1301 Medical Sciences Research Building III, Ann Arbor, MI 48109; and
| | - Xavier Deupi
- Laboratori de Medicina Computacional, Unitat de Bioestadística, Facultat de Medicina, Universitat Autònoma de Barcelona, 08193 Bellaterra, Catalunya, Spain
| | - Roger K. Sunahara
- Department of Pharmacology, University of Michigan Medical School, 1301 Medical Sciences Research Building III, Ann Arbor, MI 48109; and
| | - Brian Kobilka
- Department of Molecular and Cellular Physiology, Stanford University Medical School Department of Chemistry, Stanford University, Stanford, CA 94305
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39
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Differences in Galpha12- and Galpha13-mediated plasma membrane recruitment of p115-RhoGEF. Cell Signal 2009; 21:996-1006. [PMID: 19249348 DOI: 10.1016/j.cellsig.2009.02.010] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2008] [Revised: 02/16/2009] [Accepted: 02/17/2009] [Indexed: 11/22/2022]
Abstract
Regulator of G protein signaling domain-containing Rho guanine-nucleotide exchange factors (RGS-RhoGEFs) directly links activated forms of the G12 family of heterotrimeric G protein alpha subunits to the small GTPase Rho. Stimulation of G(12/13)-coupled GPCRs or expression of constitutively activated forms of alpha(12) and alpha(13) has been shown to induce the translocation of the RGS-RhoGEF, p115-RhoGEF, from the cytoplasm to the plasma membrane (PM). However, little is known regarding the functional importance and mechanisms of this regulated PM recruitment, and thus PM recruitment of p115-RhoGEF is the focus of this report. A constitutively PM-localized mutant of p115-RhoGEF shows a much greater activity compared to wild type p115-RhoGEF in promoting Rho-dependent neurite retraction of NGF-differentiated PC12 cells, providing the first evidence that PM localization can activate p115-RhoGEF signaling. Next, we uncovered the unexpected finding that Rho is required for alpha(13)-induced PM translocation of p115-RhoGEF. However, inhibition of Rho did not prevent alpha(12)-induced PM translocation of p115-RhoGEF. Additional differences between alpha(13) and alpha(12) in promoting PM recruitment of p115-RhoGEF were revealed by analyzing RGS domain mutants of p115-RhoGEF. Activated alpha(12) effectively recruits the isolated RGS domain of p115-RhoGEF to the PM, whereas alpha(13) only weakly does. On the other hand, alpha(13) strongly recruits to the PM a p115-RhoGEF mutant containing amino acid substitutions in an acidic region at the N-terminus of the RGS domain; however, alpha(12) is unable to recruit this p115-RhoGEF mutant to the PM. These studies provide new insight into the function and mechanisms of alpha(12/13)-mediated PM recruitment of p115-RhoGEF.
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40
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Suzuki N, Hajicek N, Kozasa T. Regulation and physiological functions of G12/13-mediated signaling pathways. Neurosignals 2009; 17:55-70. [PMID: 19212140 DOI: 10.1159/000186690] [Citation(s) in RCA: 75] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2008] [Accepted: 10/10/2008] [Indexed: 12/12/2022] Open
Abstract
Accumulating data indicate that G12 subfamily (Galpha12/13)-mediated signaling pathways play pivotal roles in a variety of physiological processes, while aberrant regulation of this pathway has been identified in various human diseases. It has been demonstrated that Galpha12/13-mediated signals form networks with other signaling proteins at various levels, from cell surface receptors to transcription factors, to regulate cellular responses. Galpha12/13 have slow rates of nucleotide exchange and GTP hydrolysis, and specifically target RhoGEFs containing an amino-terminal RGS homology domain (RH-RhoGEFs), which uniquely function both as a GAP and an effector for Galpha12/13. In this review, we will focus on the mechanisms regulating the Galpha12/13 signaling system, particularly the Galpha12/13-RH-RhoGEF-Rho pathway, which can regulate a wide variety of cellular functions from migration to transformation.
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Affiliation(s)
- Nobuchika Suzuki
- Laboratory of Systems Biology and Medicine, Research Center for Advanced Science and Technology, The University of Tokyo, Tokyo, Japan.
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41
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Recognition of the activated states of Galpha13 by the rgRGS domain of PDZRhoGEF. Structure 2008; 16:1532-43. [PMID: 18940608 DOI: 10.1016/j.str.2008.07.009] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2008] [Revised: 07/29/2008] [Accepted: 07/29/2008] [Indexed: 12/13/2022]
Abstract
G12 class heterotrimeric G proteins stimulate RhoA activation by RGS-RhoGEFs. However, p115RhoGEF is a GTPase Activating Protein (GAP) toward Galpha13, whereas PDZRhoGEF is not. We have characterized the interaction between the PDZRhoGEF rgRGS domain (PRG-rgRGS) and the alpha subunit of G13 and have determined crystal structures of their complexes in both the inactive state bound to GDP and the active states bound to GDP*AlF (transition state) and GTPgammaS (Michaelis complex). PRG-rgRGS interacts extensively with the helical domain and the effector-binding sites on Galpha13 through contacts that are largely conserved in all three nucleotide-bound states, although PRG-rgRGS has highest affinity to the Michaelis complex. An acidic motif in the N terminus of PRG-rgRGS occupies the GAP binding site of Galpha13 and is flexible in the GDP*AlF complex but well ordered in the GTPgammaS complex. Replacement of key residues in this motif with their counterparts in p115RhoGEF confers GAP activity.
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42
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Suzuki N, Tsumoto K, Hajicek N, Daigo K, Tokita R, Minami S, Kodama T, Hamakubo T, Kozasa T. Activation of leukemia-associated RhoGEF by Galpha13 with significant conformational rearrangements in the interface. J Biol Chem 2008; 284:5000-9. [PMID: 19074425 DOI: 10.1074/jbc.m804073200] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
The transient protein-protein interactions induced by guanine nucleotide-dependent conformational changes of G proteins play central roles in G protein-coupled receptor-mediated signaling systems. Leukemia-associated RhoGEF (LARG), a guanine nucleotide exchange factor for Rho, contains an RGS homology (RH) domain and Dbl homology/pleckstrin homology (DH/PH) domains and acts both as a GTPase-activating protein (GAP) and an effector for Galpha(13). However, the molecular mechanism of LARG activation upon Galpha(13) binding is not yet well understood. In this study, we analyzed the Galpha(13)-LARG interaction using cellular and biochemical methods, including a surface plasmon resonance (SPR) analysis. The results obtained using various LARG fragments demonstrated that active Galpha(13) interacts with LARG through the RH domain, DH/PH domains, and C-terminal region. However, an alanine substitution at the RH domain contact position in Galpha(13) resulted in a large decrease in affinity. Thermodynamic analysis revealed that binding of Galpha(13) proceeds with a large negative heat capacity change (DeltaCp degrees ), accompanied by a positive entropy change (DeltaS degrees ). These results likely indicate that the binding of Galpha(13) with the RH domain triggers conformational rearrangements between Galpha(13) and LARG burying an exposed hydrophobic surface to create a large complementary interface, which facilitates complex formation through both GAP and effector interfaces, and activates the RhoGEF. We propose that LARG activation is regulated by an induced-fit mechanism through the GAP interface of Galpha(13).
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Affiliation(s)
- Nobuchika Suzuki
- Laboratory of Systems Biology and Medicine, Research Center for Advanced Science and Technology, The University of Tokyo, Tokyo 153-8904, Japan
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43
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Shankaranarayanan A, Thal DM, Tesmer VM, Roman DL, Neubig RR, Kozasa T, Tesmer JJG. Assembly of high order G alpha q-effector complexes with RGS proteins. J Biol Chem 2008; 283:34923-34. [PMID: 18936096 DOI: 10.1074/jbc.m805860200] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Transmembrane signaling through G alpha(q)-coupled receptors is linked to physiological processes such as cardiovascular development and smooth muscle function. Recent crystallographic studies have shown how G alpha(q) interacts with two activation-dependent targets, p63RhoGEF and G protein-coupled receptor kinase 2 (GRK2). These proteins bind to the effector-binding site of G alpha(q) in a manner that does not appear to physically overlap with the site on G alpha(q) bound by regulator of G-protein signaling (RGS) proteins, which function as GTPase-activating proteins (GAPs). Herein we confirm the formation of RGS-G alpha(q)-GRK2/p63RhoGEF ternary complexes using flow cytometry protein interaction and GAP assays. RGS2 and, to a lesser extent, RGS4 are negative allosteric modulators of Galpha(q) binding to either p63RhoGEF or GRK2. Conversely, GRK2 enhances the GAP activity of RGS4 but has little effect on that of RGS2. Similar but smaller magnitude responses are induced by p63RhoGEF. The fact that GRK2 and p63RhoGEF respond similarly to these RGS proteins supports the hypothesis that GRK2 is a bona fide G alpha(q) effector. The results also suggest that signal transduction pathways initiated by GRK2, such as the phosphorylation of G protein-coupled receptors, and by p63RhoGEF, such as the activation of gene transcription, can be regulated by RGS proteins via both allosteric and GAP mechanisms.
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44
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Sayar K, Uğur Ö, Liu T, Hilser VJ, Onaran O. Exploring allosteric coupling in the alpha-subunit of heterotrimeric G proteins using evolutionary and ensemble-based approaches. BMC STRUCTURAL BIOLOGY 2008; 8:23. [PMID: 18454845 PMCID: PMC2422842 DOI: 10.1186/1472-6807-8-23] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/04/2007] [Accepted: 05/02/2008] [Indexed: 11/24/2022]
Abstract
BACKGROUND Allosteric coupling, which can be defined as propagation of a perturbation at one region of the protein molecule (such as ligand binding) to distant sites in the same molecule, constitutes the most general mechanism of regulation of protein function. However, unlike molecular details of ligand binding, structural elements involved in allosteric effects are difficult to diagnose. Here, we identified allosteric linkages in the alpha-subunits of heterotrimeric G proteins, which were evolved to transmit membrane receptor signals by allosteric mechanisms, by using two different approaches that utilize fundamentally different and independent information. RESULTS We analyzed: 1) correlated mutations in the family of G protein alpha-subunits, and 2) cooperativity of the native state ensemble of the Galphai1 or transducin. The combination of these approaches not only recovered already-known details such as the switch regions that change conformation upon nucleotide exchange, and those regions that are involved in receptor, effector or Gbetagamma interactions (indicating that the predictions of the analyses can be viewed with a measure of confidence), but also predicted new sites that are potentially involved in allosteric communication in the Galpha protein. A summary of the new sites found in the present analysis, which were not apparent in crystallographic data, is given along with known functional and structural information. Implications of the results are discussed. CONCLUSION A set of residues and/or structural elements that are potentially involved in allosteric communication in Galpha is presented. This information can be used as a guide to structural, spectroscopic, mutational, and theoretical studies on the allosteric network in Galpha proteins, which will provide a better understanding of G protein-mediated signal transduction.
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Affiliation(s)
- Kemal Sayar
- Ankara University Faculty of Medicine, Department of Pharmacology and Clinical Pharmacology, Sıhhiye 06100, Ankara, Turkey
- Ankara University Faculty of Medicine, and Molecular Biology and Technology Research and Development Unit, Sıhhiye 06100, Ankara, Turkey
| | - Özlem Uğur
- Ankara University Faculty of Medicine, Department of Pharmacology and Clinical Pharmacology, Sıhhiye 06100, Ankara, Turkey
| | - Tong Liu
- Department of Biochemistry and Molecular Biology, and Sealy Center for Structural Biology and Molecular Biophysics, University of Texas Medical Branch, Galveston, TX, 77555-1068 USA
| | - Vincent J Hilser
- Department of Biochemistry and Molecular Biology, and Sealy Center for Structural Biology and Molecular Biophysics, University of Texas Medical Branch, Galveston, TX, 77555-1068 USA
| | - Ongun Onaran
- Ankara University Faculty of Medicine, Department of Pharmacology and Clinical Pharmacology, Sıhhiye 06100, Ankara, Turkey
- Ankara University Faculty of Medicine, and Molecular Biology and Technology Research and Development Unit, Sıhhiye 06100, Ankara, Turkey
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45
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Molecular architecture of Galphao and the structural basis for RGS16-mediated deactivation. Proc Natl Acad Sci U S A 2008; 105:6243-8. [PMID: 18434540 DOI: 10.1073/pnas.0801569105] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Heterotrimeric G proteins relay extracellular cues from heptahelical transmembrane receptors to downstream effector molecules. Composed of an alpha subunit with intrinsic GTPase activity and a betagamma heterodimer, the trimeric complex dissociates upon receptor-mediated nucleotide exchange on the alpha subunit, enabling each component to engage downstream effector targets for either activation or inhibition as dictated in a particular pathway. To mitigate excessive effector engagement and concomitant signal transmission, the Galpha subunit's intrinsic activation timer (the rate of GTP hydrolysis) is regulated spatially and temporally by a class of GTPase accelerating proteins (GAPs) known as the regulator of G protein signaling (RGS) family. The array of G protein-coupled receptors, Galpha subunits, RGS proteins and downstream effectors in mammalian systems is vast. Understanding the molecular determinants of specificity is critical for a comprehensive mapping of the G protein system. Here, we present the 2.9 A crystal structure of the enigmatic, neuronal G protein Galpha(o) in the GTP hydrolytic transition state, complexed with RGS16. Comparison with the 1.89 A structure of apo-RGS16, also presented here, reveals plasticity upon Galpha(o) binding, the determinants for GAP activity, and the structurally unique features of Galpha(o) that likely distinguish it physiologically from other members of the larger Galpha(i) family, affording insight to receptor, GAP and effector specificity.
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46
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Refolding of G protein α subunits from inclusion bodies expressed in Escherichia coli. Protein Expr Purif 2008; 58:342-55. [DOI: 10.1016/j.pep.2007.11.015] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2007] [Revised: 11/29/2007] [Accepted: 11/30/2007] [Indexed: 10/22/2022]
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47
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Austin RJ, Ja WW, Roberts RW. Evolution of class-specific peptides targeting a hot spot of the Galphas subunit. J Mol Biol 2008; 377:1406-18. [PMID: 18329041 DOI: 10.1016/j.jmb.2008.01.032] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2007] [Revised: 12/20/2007] [Accepted: 01/14/2008] [Indexed: 11/16/2022]
Abstract
The four classes of heterotrimeric G-protein alpha subunits act as molecular routers inside cells, gating signals based on a bound guanosine nucleotide (guanosine 5'-triphosphate versus guanosine 5'-diphosphate). Ligands that specifically target individual subunits provide new tools for monitoring and modulating these networks, but are challenging to design due to the high sequence homology and structural plasticity of the Galpha-binding surface. Here we have created an mRNA display library of peptides based on the short Galpha-modulating peptide R6A-1 and selected variants that target a convergent protein-binding surface of Galphas.guanosine 5'-diphosphate. After selection/evolution, the most Galphas-specific peptide, Galphas(s)-binding peptide (GSP), was used to design a second-generation library, resulting in several new affinity- and selectivity-matured peptides denoted as mGSPs. The two-step evolutionary walk from R6A-1 to mGSP-1 resulted in an 8000-fold inversion in binding specificity, altered seven out of nine residues in the starting peptide core, and incorporated both positive and negative design steps. The resulting mGSP-1 peptide shows remarkable selectivity and affinity, exhibiting little or no binding to nine homologous Galpha subunits or human H-Ras, and even discriminates the Galphas splice variant Galphas(l). Selected peptides make specific contacts with the effector-binding region of Galpha, which may explain an interesting bifunctional activity observed in GSP. Overall, our work demonstrates a design of simple, linear, highly specific peptides that target a protein-binding surface of Galphas and argues that mRNA display-based selection/evolution is a powerful route for targeting protein families with high class specificity and state specificity.
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Affiliation(s)
- Ryan J Austin
- Department of Chemistry, University of Southern California, Los Angeles, CA 90089, USA
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48
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Rojas RJ, Yohe ME, Gershburg S, Kawano T, Kozasa T, Sondek J. Galphaq directly activates p63RhoGEF and Trio via a conserved extension of the Dbl homology-associated pleckstrin homology domain. J Biol Chem 2007; 282:29201-10. [PMID: 17606614 PMCID: PMC2655113 DOI: 10.1074/jbc.m703458200] [Citation(s) in RCA: 121] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
The coordinated cross-talk from heterotrimeric G proteins to Rho GTPases is essential during a variety of physiological processes. Emerging data suggest that members of the Galpha(12/13) and Galpha(q/11) families of heterotrimeric G proteins signal downstream to RhoA via distinct pathways. Although studies have elucidated mechanisms governing Galpha(12/13)-mediated RhoA activation, proteins that functionally couple Galpha(q/11) to RhoA activation have remained elusive. Recently, the Dbl-family guanine nucleotide exchange factor (GEF) p63RhoGEF/GEFT has been described as a novel mediator of Galpha(q/11) signaling to RhoA based on its ability to synergize with Galpha(q/11) resulting in enhanced RhoA signaling in cells. We have used biochemical/biophysical approaches with purified protein components to better understand the mechanism by which activated Galpha(q) directly engages and stimulates p63RhoGEF. Basally, p63RhoGEF is autoinhibited by the Dbl homology (DH)-associated pleckstrin homology (PH) domain; activated Galpha(q) relieves this autoinhibition by interacting with a highly conserved C-terminal extension of the PH domain. This unique extension is conserved in the related Dbl-family members Trio and Kalirin and we show that the C-terminal Rho-specific DH-PH cassette of Trio is similarly activated by Galpha(q).
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Affiliation(s)
- Rafael J Rojas
- Department of Pharmacology, University of North Carolina, Chapel Hill, North Carolina 27599, USA
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49
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Zhu D, Tate RI, Ruediger R, Meigs TE, Denker BM. Domains Necessary for Gα12Binding and Stimulation of Protein Phosphatase-2A (PP2A): Is Gα12a Novel Regulatory Subunit of PP2A? Mol Pharmacol 2007; 71:1268-76. [PMID: 17303700 DOI: 10.1124/mol.106.033555] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
Many cellular signaling pathways share regulation by protein phosphatase-2A (PP2A), a widely expressed serine/threonine phosphatase, and the heterotrimeric G protein Galpha(12). PP2A activity is altered in carcinogenesis and in some neurodegenerative diseases. We have identified binding of Galpha(12) with the Aalpha subunit of PP2A, a trimeric enzyme composed of A (scaffolding), B (regulatory), and C (catalytic) subunits and demonstrated that Galpha(12) stimulated phosphatase activity (J Biol Chem 279: 54983-54986, 2004). We now show in substrate-velocity analysis using purified PP2A that V(max) was stimulated 3- to 4-fold by glutathione transferase (GST)-Galpha(12) with little effect on K(m) values. To identify the binding domains mediating the Aalpha-Galpha(12) interaction, an extensive mutational analysis was performed. Well-characterized mutations of Aalpha were expressed in vitro and tested for binding to GST-Galpha(12) in pull-down assays. Galpha(12) binds to Aalpha along repeats 7 to 10, and PP2A B subunits are not necessary for binding. To identify where Aalpha binds to Galpha(12), a series of 61 Galpha(12) mutants were engineered to contain the sequence Asn-Ala-Ala-Ile-Arg-Ser (NAAIRS) in place of 6 consecutive amino acids. Mutant Galpha(12) proteins were individually expressed in human embryonic kidney cells and analyzed for interaction with GST or GST-Aalpha in pull-down assays. The Aalpha binding sites were localized to regions near the N and C termini of Galpha(12). The expression of constitutively activated Galpha(12) (QLalpha(12)) in Madin Darby canine kidney cells stimulated PP2A activity as determined by decreased phosphorylation of tyrosine 307 on the catalytic subunit. Based on crystal structures of Galpha(12) and PP2A Aalpha, a model describing the binding surfaces and potential mechanisms of Galpha(12)-mediated PP2A activation is presented.
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Affiliation(s)
- Deguang Zhu
- Renal Division, Brigham and Women's Hospital, and Harvard Medical School, Boston, Massachusetts 02115, USA
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50
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Morikawa T, Muroya A, Nakajima Y, Tanaka T, Hirai K, Sugio S, Wakamatsu K, Kohno T. Crystallization and preliminary X-ray crystallographic analysis of the receptor-uncoupled mutant of Galphai1. Acta Crystallogr Sect F Struct Biol Cryst Commun 2007; 63:139-41. [PMID: 17277460 PMCID: PMC2330130 DOI: 10.1107/s1744309107003363] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2006] [Accepted: 01/22/2007] [Indexed: 11/11/2022]
Abstract
In order to understand the molecular mechanisms by which G-protein-coupled receptors (GPCRs) activate G proteins, the K349P mutant of Galpha(i1) (K349P), which is unable to couple to the muscarinic acetylcholine receptor, was prepared and its crystals were grown along with those of wild-type Galpha(i1) protein (WT). The two proteins were crystallized under almost identical conditions, thus enabling a detailed structural comparison. The crystallization conditions performed well irrespective of the identity of the bound nucleotide (GDP or GTPgammaS) and the crystals diffracted to resolutions of 2.2 A (WT.GDP), 2.8 A (WT.GTPgammaS), 2.6 A (K349P.GDP) and 3.2 A (K349P.GTPgammaS).
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Affiliation(s)
- Tomohito Morikawa
- Mitsubishi Kagaku Institute of Life Sciences (MITILS), 11 Minamiooya, Machida, Tokyo 194-8511, Japan
- Department of Biological and Chemical Engineering, Faculty of Engineering, Gunma University, 1-5-1 Tenjin-cho, Kiryu, Gunma 376-8515, Japan
| | - Ayumu Muroya
- Mitsubishi Chemical Corporation, 1000 Kamoshida, Aoba, Yokohama 227-8502, Japan
- ZOEGENE Corporation, 1000 Kamoshida, Aoba, Yokohama 227-8502, Japan
| | - Yoshitaka Nakajima
- Mitsubishi Chemical Corporation, 1000 Kamoshida, Aoba, Yokohama 227-8502, Japan
| | - Takeshi Tanaka
- Mitsubishi Kagaku Institute of Life Sciences (MITILS), 11 Minamiooya, Machida, Tokyo 194-8511, Japan
| | - Keiko Hirai
- Mitsubishi Kagaku Institute of Life Sciences (MITILS), 11 Minamiooya, Machida, Tokyo 194-8511, Japan
| | - Shigetoshi Sugio
- Mitsubishi Chemical Corporation, 1000 Kamoshida, Aoba, Yokohama 227-8502, Japan
- ZOEGENE Corporation, 1000 Kamoshida, Aoba, Yokohama 227-8502, Japan
- Correspondence e-mail: , ,
| | - Kaori Wakamatsu
- Department of Biological and Chemical Engineering, Faculty of Engineering, Gunma University, 1-5-1 Tenjin-cho, Kiryu, Gunma 376-8515, Japan
- Correspondence e-mail: , ,
| | - Toshiyuki Kohno
- Mitsubishi Kagaku Institute of Life Sciences (MITILS), 11 Minamiooya, Machida, Tokyo 194-8511, Japan
- Correspondence e-mail: , ,
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