Role of the MAPK cascade in mammalian germ cells

The mitogen-activated protein kinase (MAPK) cascade is one of the most impo rtant of the intracellular signaling pathways that play a crucial role in c ell proliferation, cell differentiation and cell cycle regulation. Since th e first report in 1993 of MAPK's involvement in the functional regulation o f mammalian oocytes, much work has been done on the role of the MAPK cascad e in germ cells in different species of mammals. This review describes the possible involvement of the MOS/MEK/MAPK/RSK cascade in spermatogenesis, sp erm function, oocyte meiotic re-initiation, spindle assembly, metaphase II arrest, pronuclear formation and the entry of first mitosis, as well as the cross-talk of this cascade to maturation-promoting factor (MPF) and other signal molecules in mammals.