zonadhesin (ZAN)

Function

• binds in a species-specific manner to the zona pellucida of the egg
• may be involved in gamete recognition &/or signaling
• probably forms covalent oligomers

Structure

• the MAM domains probably mediate sperm adhesion to the zona pellucida
• during sperm migration through the reproductive tracts, the mucin-like domain might inhibit inappropriate trapping of spermatozoa or promoting adhesion to the oviductal isthmus
• the VWFD domain 2 may mediate covalent oligomerization
• contains 1 EGF-like domain
• contains 3 MAM domains
• contains 4 TIL (trypsin inhibitory-like) domains
• contains 5 VWFC domains
• contains 4 VWFD domains

Compartment

• cell membrane; single-pass type 1 membrane protein.
• exclusively on the apical region of the sperm head

Alternative splicing

• named isoforms=7
• some isoforms may be produced at very low levels due to a premature stop codon in the mRNA, leading to nonsense-mediated mRNA decay

Expression

• in testis, primarily in haploid spermatids

More general terms

• membrane protein
• glycoprotein

Database

• Entrez gene: http://www.ncbi.nlm.nih.gov/sites/entrez?db=gene&cmd=Retrieve&dopt=Graphics&list_uids=7455
• Kegg: http://www.genome.jp/dbget-bin/www_bget?hsa:7455
• OMIM: https://mirror.omim.org/entry/602372
• UniProt: http://www.uniprot.org/uniprot/Q9Y493.html