Ric-8A catalyzes guanine nucleotide exchange on G alphai1 bound to the GPR/GoLoco exchange inhibitor AGS3.

ABSTRACT: Microtubule pulling forces that govern mitotic spindle movement of chromosomes are tightly regulated by G-proteins. A host of proteins, including Galpha subunits, Ric-8, AGS3, regulators of G-protein signalings, and scaffolding proteins, coordinate this vital cellular process. Ric-8A, acting as a guanine nucleotide exchange factor, catalyzes the release of GDP from various Galpha.GDP subunits and forms a stable nucleotide-free Ric-8A:Galpha complex. AGS3, a guanine nucleotide dissociation inhibitor (GDI), binds and stabilizes Galpha subunits in their GDP-bound state. Because Ric-8A and AGS3 may recognize and compete for Galpha.GDP in this pathway, we probed the interactions of a truncated AGS3 (AGS3-C; containing only the residues responsible for GDI activity), with Ric-8A:Galpha(il) and t

SUBMITTER: Thomas CJ 

PROVIDER: S-EPMC2516996 | biostudies-literature | 2008 Aug

REPOSITORIES: biostudies-literature