Zona pellucida sperm-binding protein 2; Zona pellucida glycoprotein ZP2; Zona pellucida protein A; contains: Processed zona pellucida sperm-binding protein 2 (ZP2 ZPA)

Function

• the mammalian zona pellucida, which mediates species-specific sperm binding, induction of the acrosome reaction & prevents post-fertilization polyspermy, is composed of 3-4 glycoproteins, ZP1, ZP2, ZP3, & ZP4
• ZP2 may act as a secondary sperm receptor
• proteolytically cleaved before the transmembrane segment to yield the secreted ectodomain incorporated in the zona pellucida
• proteolytically cleaved in the N-terminal part after fertilization, yielding a N-terminal peptide of about 30 kD which remains covalently attached to the C-terminal peptide via disulfide bond(s); this cleavage may play a role in post-fertilization block to polyspermy (putative)
• O-glycosylated; contains sulfate-substituted glycans
• polymers of ZP2 & ZP3 organized into long filaments cross-linked by ZP1 homodimers (putative)

Structure

• the ZP domain is involved in the polymerization of the ZP proteins to form the zona pellucida
• belongs to the ZP domain family, ZPA subfamily
• contains 1 ZP domain

Compartment

• processed zona pellucida sperm-binding protein 2:
  • secreted, extracellular space, extracellular matrix
• cell membrane; single-pass type 2 membrane protein

Expression

• oocytes
• expressed during the 2-week growth phase of oogenesis, prior to ovulation

More general terms

• membrane protein
• receptor
• glycoprotein
• matrix protein

Database

• UniProt: http://www.uniprot.org/uniprot/Q05996.html
• Entrez gene: http://www.ncbi.nlm.nih.gov/sites/entrez?db=gene&cmd=Retrieve&dopt=Graphics&list_uids=7783
• Kegg: http://www.genome.jp/dbget-bin/www_bget?hsa:7783
• OMIM: https://mirror.omim.org/entry/182888