Prostaglandin F(2α) stimulates formation of p21(ras)-GTP complex and mitogen-activated protein kinase in NIH-3T3 cells via G(q)-protein-coupled pathway

Abstract

Prostaglandin (PG) F(2α) activated mitogen-activated protein (MAP) kinase and MAP kinase kinase in NIH-3T3 cells by a mechanism that was completely inhibited by protein kinase inhibitors, staurosporine (20 nM) or H-7 (20 μM), but was insensitive to pretreatment with islet-activating protein (100 ng/ml; 24 h) or 12-O-tetra-decanoylphorbol 13-acetate (2.5 μM; 24 h). PGF(2α) stimulation also led to a significant increase in Ras · GTP complex. Transfection of a cDNA encoding a constitutively active mutant of G(q) α-subunit (Q209L) mimicked PGF(2α)-induced MAP kinase activation, increase in Ras · GTP complex, and DNA synthesis in these cells, suggesting that activation of G(q) mediates the PGF(2α)-activation of Ras-MAP kinase pathway and mitogenesis in NIH-3T3 cells. These data provide a new insight into regulatory mechanisms of Ras-MAP kinase pathway through heterotrimeric G-protein-mediated pathways.