title: G Protein-coupled receptors: Multi-turnover GDP/GTP exchange catalysis on heterotrimeric G proteins.
abstract: G protein-coupled receptors and heterotrimeric G proteins can diffuse laterally in the plasma membrane such that one receptor can catalyze the activation (GDP/GTP exchange) of multiple G proteins. In some cases, these processes are fast enough to support molecular signal amplification, where a single receptor maintains the activation of multiple G proteins at steady-state. Amplification in cells is probably highly regulated. It depends upon the identities of the G receptor and G protein - some do and some don't - and upon the activities of GTPase-activating proteins, membrane scaffolds, and other regulatory partners.
authors.affiliation: Department of Pharmacology and Green Center for Systems Biology; University of Texas Southwestern Medical Center; Dallas, TX USA.
authors.forename: Elliott M
authors.initials: EM
authors.lastname: Ross
keywords: GAPs (GTPase activating proteins); GEFs (guanine nucleotide exchange factors); GPCRs (G protein coupled receptors); GTPases/G proteins; effectors