In summary, we have demonstrated that ectopically expressed OR51E2 is a potent activator of the MAPKs ERK1/2 in prostate cancer cells and that the function of OR51E2 in activating ERK1/2 is mediated through a specific GA-localized Gβγ-PI3Kγ-ARF1 pathway. The gene discussed is MAPK3; the disease is prostate cancer.