β-Arrestin-mediated Recruitment of the Src Family Kinase Yes Mediates Endothelin-1-stimulated Glucose Transport

Abstract

The insulin and the endothelin type A (ETA) receptor both can couple into the heterotrimeric G protein αq/11 (Gαq/11), leading to Gαq/11 tyrosine phosphorylation, phosphatidylinositol 3-kinase activation, and subsequent stimulation of glucose transport. In this study, we assessed the potential role of Src kinase in ET-1 signaling to glucose transport in 3T3-L1 adipocytes. Src kinase inhibitor PP2 blocked ET-1-induced Src kinase activity, Gαq/11 tyrosine phosphorylation, and glucose transport stimulation. To determine which Src family kinase member was involved, we microinjected anti-c-Src, -c-Fyn, or -c-Yes antibody into these cells and found that only anti-c-Yes antibody blocked GLUT4 translocation (70% decreased). Overexpression or microinjection of a dominant negative mutant (K298M) of Src kinase also inhibited ET-1-induced Gαq/11 tyrosine phosphorylation and GLUT4 translocation. In co-immunoprecipitation experiments, we found that β-arrestin 1 associated with the ETA receptor in an agonist-dependent manner and that β-arrestin 1 recruited Src kinase to a molecular complex that included the ETA receptor. Microinjection of β-arrestin 1 antibody inhibited ET-1- but not insulin-stimulated GLUT4 translocation. In conclusion, 1) the Src kinase Yes can induce tyrosine phosphorylation of Gαq/11 in response to ET-1 stimulation, and 2) β-arrestin 1 and Src kinase form a molecular complex with the ETA receptor to mediate ET-1 signaling to Gα q/11 with subsequent glucose transport stimulation.