Figure 1: Schematic representation of known mechanisms of action of the sperm proteins, PLCζ (left side) and PAWP (right side) in mammalian oocytes. ER: endoplasmic reticulum; PIP2: phosphatidylinositol 4,5-bisphosphate; IP3: inositol 1,4,5-trisphosphate; PAWP: postacrosomal WW domain-binding protein; PLCζ: phospholipase C zeta.