Cellular ERK signaling pathway, one of the three major mitogen-activated protein kinase (MAPK) cascades, which consists of three tiered serine/threonine kinases of Raf, MEK and ERK, plays an important role in regulating cell physiological functions [12,13,14] as well as many pathologic processes, including brain injury, cancer, diabetes, infectious diseases and inflammation etc. [15,16,17,18]. The gene discussed is MAPK1; the disease is diabetes mellitus.