G protein coupled receptor signaling complexes in live cells.

• Authors: John Hepler, Emory University
• Journal Title: Cellular Logistics
• Volume: Volume 4
• Publisher: Taylor & Francis | 2014, Pages e29392-e29392
• Type of Work: Article | Final Publisher PDF
• Publisher DOI: http://doi.org/10.4161/cl.29392
• Subjects: Health Sciences, Pharmacology; Health Sciences, General
• Keywords: ARF; GAPs (GTPase activating proteins); GEFs (guanine nucleotide exchange factors); GPCRs (G protein coupled receptors); GTPases/G proteins; RAB; RAS; effectors

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.