title: G protein coupled receptor signaling complexes in live cells.
abstract: Classical models of receptor (GPCR) and G protein (Gαβγ) signaling based on biochemical studies have proposed that receptor stimulation results in G protein activation (Gα-GTP) and dissociation of the heterotrimer (Gα-GTP + Gβγ) to regulate downstream signaling events. Unclear is whether or not there exists freely diffusible, activated Gα-GTP on cellular membranes capable of catalytic signal amplification. Recent studies in live cells indicate that GPCRs serve as platforms for the assembly of macromolecular signaling complexes that include G proteins to support a highly efficient and spatially restricted signaling event, with no requirement for full Gα-GTP and Gβγ dissociation and lateral diffusion within the plasma membrane.
authors.affiliation: Department of Pharmacology; Emory University School of Medicine; Atlanta, GA USA.
authors.forename: John R
authors.initials: JR
authors.lastname: Hepler
keywords: ARF; GAPs (GTPase activating proteins); GEFs (guanine nucleotide exchange factors); GPCRs (G protein coupled receptors); GTPases/G proteins; RAB; RAS; effectors