Role of the highly conserved Asp-Arg-Tyr motif in signal transduction of the CB2 cannabinoid receptor

The DRY motif, at the junction of transmembrane helix 3 and intracellular l oop 2 of G protein-coupled receptors, is highly conserved. Mutations were i ntroduced into the CB2 cannabinoid receptor to studs the role of this motif in CB2 signaling, D mutations (DPY130-132AAA and D130A) markedly reduced b inding of cannabinoid agonists, while no significant reduction was observed sith R131A or Y132A. Mutating a (R131A) only partially reduced, and mutati ng Y (Y132A) more efficiently reduced the cannabinoid-induced inhibition of adenylyl cyclase. Thus, in CB2, D130 is involved in agonist binding, where as Y seems to have a role in receptor downstream signaling, (C) 2000 Federa tion of European Biochemical Societies.