4ekd

Publication Abstract from PubMed

The heterotrimeric G protein Galphaq is a key regulator of blood pressure, and excess Galphaq signaling leads to hypertension. A specific inhibitor of Galphaq is the GTPase activating protein (GAP) known as regulator of G protein signaling 2 (RGS2). The molecular basis for how Galphaq/11 subunits serve as substrates for RGS proteins and how RGS2 mandates its selectivity for Galphaq is poorly understood. In crystal structures of the RGS2-Galphaq complex, RGS2 docks to Galphaq in a different orientation from that observed in RGS-Galphai/o complexes. Despite its unique pose, RGS2 maintains canonical interactions with the switch regions of Galphaq in part because its alpha6 helix adopts a distinct conformation. We show that RGS2 forms extensive interactions with the alpha-helical domain of Galphaq that contribute to binding affinity and GAP potency. RGS subfamilies that do not serve as GAPs for Galphaq are unlikely to form analogous stabilizing interactions.

Structural and functional analysis of the regulator of G protein signaling 2-galphaq complex.,Nance MR, Kreutz B, Tesmer VM, Sterne-Marr R, Kozasa T, Tesmer JJ Structure. 2013 Mar 5;21(3):438-48. doi: 10.1016/j.str.2012.12.016. Epub 2013 Feb, 21. PMID:23434405^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.