| Title: | Dominant-negative inhibition of pheromone receptor signaling by a single point mutation in the G protein alpha subunit |
| Author(s): | Wu YL; Hooks SB; Harden TK; Dohlman HG; |
| Address: | "Department of Biochemistry and Biophysics, University of North Carolina, Chapel Hill 27599-7260, USA" |
| ISSN/ISBN: | 0021-9258 (Print) 0021-9258 (Linking) |
| Abstract: | "In yeast, two different constitutive mutants of the G protein alpha subunit have been reported. Gpa1(Q323L) cannot hydrolyze GTP and permanently activates the pheromone response pathway. Gpa1(N388D) was also proposed to lack GTPase activity, yet it has an inhibitory effect on pheromone responsiveness. We have characterized this inhibitory mutant (designated Galpha(ND)) and found that it binds GTP, interacts with G protein betagamma subunits, and exhibits full GTPase activity in vitro. Although pheromone leads to dissociation of the receptor from wild-type G protein, the same treatment promotes stable association of the receptor with Galpha(ND). We conclude that agonist binding to the receptor promotes the formation of a nondissociable complex with Galpha(ND), and in this manner prevents activation of the endogenous wild-type G protein. Dominant-negative mutants may be useful in matching specific receptors and their cognate G proteins and in determining mechanisms of G protein signaling specificity" |
| Keywords: | "Escherichia coli GTP-Binding Protein alpha Subunits/genetics/metabolism GTP-Binding Protein alpha Subunits, Gq-G11 Point Mutation Receptors, Pheromone/*physiology Saccharomyces cerevisiae Saccharomyces cerevisiae Proteins/genetics/metabolism *Signal Trans;" |
| Notes: | "MedlineWu, Yuh-Lin Hooks, Shelley B Harden, T Kendall Dohlman, Henrik G eng P01 GM065533/GM/NIGMS NIH HHS/ F32-GM66561/GM/NIGMS NIH HHS/ P01-GM65533/GM/NIGMS NIH HHS/ Research Support, U.S. Gov't, P.H.S. 2004/06/16 J Biol Chem. 2004 Aug 20; 279(34):35287-97. doi: 10.1074/jbc.M404896200. Epub 2004 Jun 14" |
