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Updated: Apr 23, 2026

Comparing the Affinity of GTPase-binding Proteins using Competition Assays
Published on: October 8, 2015
G Protein-coupled receptors: Multi-turnover GDP/GTP exchange catalysis on heterotrimeric G proteins
1Department of Pharmacology and Green Center for Systems Biology; University of Texas Southwestern Medical Center; Dallas, TX USA.
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.
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