N terminus of type 5 adenylyl cyclase scaffolds Gs heterotrimer.

ABSTRACT: According to accepted doctrine, agonist-bound G protein-coupled receptors catalyze the exchange of GDP for GTP and facilitate the dissociation of Galpha and Gbetagamma, which in turn regulate their respective effectors. More recently, the existence of preformed signaling complexes, which may include receptors, heterotrimeric G proteins, and/or effectors, is gaining acceptance. We show herein the existence of a preformed complex of inactive heterotrimer (Galpha(s) x betagamma) and the effector type 5 adenylyl cyclase (AC5), localized by the N terminus of AC5. GST fusions of AC5 N terminus (5NT) bind to purified G protein subunits (GDP-Galpha(s) and Gbetagamma) with apparent affinities of 270 +/- 21 and 190 +/- 7 nM, respectively. GDP-bound Galpha(s) and Gbetagamma did not compete, but rathe

SUBMITTER: Sadana R 

PROVIDER: S-EPMC2784731 | biostudies-literature | 2009 Dec

REPOSITORIES: biostudies-literature