title: Peptides as probes for G protein signal transduction.
abstract: Triggered by agonist binding to cell surface receptors, the heterotrimeric G proteins dissociate into alpha and beta gamma subunits, each activating distinct second messenger pathways. Peptides from the primary sequences of receptors, G proteins, and effectors have been used to study the molecular interactions between these proteins. Receptor-derived peptides from the second, third and fourth intracellular loops and certain naturally occurring peptides antagonize G protein interactions and can directly activate G protein. These peptides bind to G protein sites that include the N and C terminal regions of the alpha subunit and a yet to be identified region of the beta subunit. Peptides have also been useful in characterizing G protein-effector interactions. The identification of the contact sites between proteins involved in G protein signal transduction should aid in the development of non-peptide mimetic therapeutics which could specifically modify G protein-mediated cellular responses.
authors.affiliation: Department of Pharmacology, University of Michigan, Ann Arbor 48109, USA.
authors.forename: J M
authors.initials: JM
authors.lastname: Taylor
authors.forename: R R
authors.initials: RR
authors.lastname: Neubig
mesh_terms: D000818:Animals; D019204:GTP-Binding Proteins / Q000502:physiology*; D015335:Molecular Probes; D010455:Peptides; D015398:Signal Transduction
chemical_list: D015335:Molecular Probes; D010455:Peptides; D019204:GTP-Binding Proteins