Fig. 2.

a Schematic representation of PLCζ, summarizing briefly the functional roles of each domain group. b Schematic illustration of the proposed mechanism of PLCζ action. Following sperm/oocyte fusion, PLCζ diffuses into ooplasm, binding to vesicular-bound PIP₂ dispersed throughout the cytoplasm. PIP₂ hydrolysis by PLCζ generates IP₃, resulting in Ca²⁺ release from the endoplasmic reticulum (ER). Increased cytosolic Ca²⁺ then further stimulates the activity of PLCζ, generating more IP₃. This positive feedback loop occurs throughout as PLCζ continues to diffuse across the ooplasm. Figure adapted from Swann and Lai [106], with permission