Component of the zona pellucida, an extracellular matrix surrounding oocytes which mediates sperm binding, induction of the acrosome reaction and prevents post-fertilization polyspermy. The zona pellucida is composed of 3 to 4 glycoproteins, ZP1, ZP2, ZP3, and ZP4. ZP4 may act as a sperm receptor.
Subcellular locations: Zona pellucida
Subcellular locations: Cell membrane
Expressed in oocytes.