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 Jun 10;286(23):20625-36. doi: 10.1074/jbc.M110.201392. Epub 2011 Apr 20.

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).

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Allosteric Regulation / physiology
  • Animals
  • Crystallography, X-Ray
  • Enzyme Activation / physiology
  • GTP-Binding Protein alpha Subunits, G12-G13 / chemistry*
  • GTP-Binding Protein alpha Subunits, G12-G13 / genetics
  • GTP-Binding Protein alpha Subunits, G12-G13 / metabolism
  • Guanine Nucleotide Exchange Factors / chemistry*
  • Guanine Nucleotide Exchange Factors / genetics
  • Guanine Nucleotide Exchange Factors / metabolism
  • Mice
  • Multienzyme Complexes / chemistry*
  • Multienzyme Complexes / genetics
  • Multienzyme Complexes / metabolism
  • Mutation
  • Protein Structure, Quaternary
  • Protein Structure, Tertiary
  • Rho Guanine Nucleotide Exchange Factors
  • Structure-Activity Relationship

Substances

  • Arhgef12 protein, mouse
  • Guanine Nucleotide Exchange Factors
  • Multienzyme Complexes
  • Rho Guanine Nucleotide Exchange Factors
  • GTP-Binding Protein alpha Subunits, G12-G13

Associated data

  • PDB/3AB3