Structure-function analysis of plant G-protein regulatory mechanisms identifies key Gα-RGS protein interactions.

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  • Additional Information
    • Source:
      Publisher: Elsevier Inc. on behalf of American Society for Biochemistry and Molecular Biology Country of Publication: United States NLM ID: 2985121R Publication Model: Print-Electronic Cited Medium: Internet ISSN: 1083-351X (Electronic) Linking ISSN: 00219258 NLM ISO Abbreviation: J Biol Chem Subsets: MEDLINE
    • Publication Information:
      Publication: 2021- : [New York, NY] : Elsevier Inc. on behalf of American Society for Biochemistry and Molecular Biology
      Original Publication: Baltimore, MD : American Society for Biochemistry and Molecular Biology
    • Subject Terms:
      GTP-Binding Protein alpha Subunits*/metabolism ; GTP-Binding Protein alpha Subunits*/chemistry ; GTP-Binding Protein alpha Subunits*/genetics ; Plant Proteins*/metabolism ; Plant Proteins*/chemistry ; Plant Proteins*/genetics ; RGS Proteins*/metabolism ; RGS Proteins*/chemistry ; RGS Proteins*/genetics ; Models, Molecular*; Arabidopsis/metabolism ; Arabidopsis/genetics ; Arabidopsis Proteins/metabolism ; Arabidopsis Proteins/chemistry ; Arabidopsis Proteins/genetics ; Crystallography, X-Ray ; Oryza/metabolism ; Oryza/genetics ; Protein Binding ; Structure-Activity Relationship ; Selaginellaceae/genetics ; Selaginellaceae/metabolism ; Protein Structure, Quaternary
    • Abstract:
      Heterotrimeric GTP-binding protein alpha subunit (Gα) and its cognate regulator of G-protein signaling (RGS) protein transduce signals in eukaryotes spanning protists, amoeba, animals, fungi, and plants. The core catalytic mechanisms of the GTPase activity of Gα and the interaction interface with RGS for the acceleration of GTP hydrolysis seem to be conserved across these groups; however, the RGS gene is under low selective pressure in plants, resulting in its frequent loss. Our current understanding of the structural basis of Gα:RGS regulation in plants has been shaped by Arabidopsis Gα, (AtGPA1), which has a cognate RGS protein. To gain a comprehensive understanding of this regulation beyond Arabidopsis, we obtained the x-ray crystal structures of Oryza sativa Gα, which has no RGS, and Selaginella moellendorffi (a lycophyte) Gα that has low sequence similarity with AtGPA1 but has an RGS. We show that the three-dimensional structure, protein-protein interaction with RGS, and the dynamic features of these Gα are similar to AtGPA1 and metazoan Gα. Molecular dynamic simulation of the Gα-RGS interaction identifies the contacts established by specific residues of the switch regions of GTP-bound Gα, crucial for this interaction, but finds no significant difference due to specific amino acid substitutions. Together, our data provide valuable insights into the regulatory mechanisms of plant G-proteins but do not support the hypothesis of adaptive co-evolution of Gα:RGS proteins in plants.
      Competing Interests: Conflict of interest Joseph M. Jez is an associate editor and Sona Pandey is an editorial board member. The other authors declare that they have no conflicts of interest with the contents of this article.
      (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)
    • Grant Information:
      R35 GM142745 United States GM NIGMS NIH HHS
    • Contributed Indexing:
      Keywords: Gα protein; RGS; Selaginella moellendorffi; activation/deactivation; plant; rice; structure
    • Accession Number:
      0 (Arabidopsis Proteins)
      0 (GTP-Binding Protein alpha Subunits)
      0 (Plant Proteins)
      0 (RGS Proteins)
    • Publication Date:
      Date Created: 20240403 Date Completed: 20240529 Latest Revision: 20240831
    • Publication Date:
      20240831
    • Accession Number:
      PMC11061236
    • Accession Number:
      10.1016/j.jbc.2024.107252
    • Accession Number:
      38569936