Role of the sea urchin egg receptor for sperm in gamete interactions.

Embryonic development is initiated by a multi-step fertilization process involving induction of the acrosome reaction in sperm, sperm-egg binding, gamete membrane fusion and egg activation. In sea urchins, acrosome-reacted sperm interact, presumably via the sperm protein bindin, with a highly glycosylated receptor on the egg surface. This article highlights the recent advances in the molecular structure of the sea urchin sperm receptor and discusses its possible role in egg activation.