PLCζ(zeta): A sperm protein that triggers Ca2+ oscillations and egg activation in mammals

At fertilization in mammals, the sperm activates development by causing a prolonged series of intracellular Ca2+ oscillations that are generated by increased production of inositol trisphosphate (InsP3). It appears that the sperm initiates InsP3 generation via the introduction of a sperm factor into the egg after gamete membrane fusion. We recently identified a sperm-specific form of phospholipase C (PLC), referred to as PLCζ(zeta). We review the evidence that PLCζ represents the sperm factor that activates development of the egg and discuss the characteristics of PLCζ that distinguish it from the somatic forms of PLC.