ZP3, one of three zona pellucida glycoproteins, serves as a structural glycoprotein, a sperm receptor, and an acrosome reaction-inducer.

The zona pellucida is a noncellular layer of carbohydrates and proteins located between the surface of the oocyte and the granulosa cell layer that secrete it.

The zona pellucida supports communication between oocytes and follicle cells during oogenesis; protects oocytes, eggs, and embryos during development, and regulates interactions between ovulated eggs and free-swimming sperm during and following fertilization.