Activation of Gi1 by lysophosphatidic acid receptor without ligand in the baculovirus expression system

Lysophosphatidic acid (LPA) receptor has been attracting many neuroscientists' concerns, since it was reported to have a potential role in the neurogenesis, which occurs in the ventricular zone of the developing and adult brain. In the present experiments using baculovirus expression system, the LPA receptor encoded by ventricular zone gene 1 (Edg-2/Vzg-1) was found to be functionally coupled to Gi1, Goa, and G11, but not to GS. The coexpression of LPA receptor markedly decreased the expression of G protein alphai1 or alphaoa subunit, while the basal [35S]GTPgammaS binding significantly increased in the Gi1-preparation. The Scatchard Plot analysis indicates that the expression of LPA-receptor (Edg-2/Vzg-1) showed stimulation of Gi1 without agonist. These results suggest the Edg-2/Vzg-1 has an intrinsic acctivity on Gi1.