EPPIN

Domain

The BPTI/Kunitz inhibitor domain is required for elastase inhibitory activity. BPTI/Kunitz inhibitor and WAP domains are involved in the protein antibacterial activity.

Function

Serine protease inhibitor that plays an essential role in male reproduction and fertility. Modulates the hydrolysis of SEMG1 by KLK3/PSA (a serine protease), provides antimicrobial protection for spermatozoa in the ejaculate coagulum, and binds SEMG1 thereby inhibiting sperm motility.

Tissue Specificity

In testis, expressed and secreted by Sertoli cells, appearing on the surface of testicular and ejaculate spermatozoa. Expressed in the spermatogonia and the earliest preleptotene spermatocytes. In the epididymis, is expressed and secreted by epithelial cells and covers the surface of epididymal spermatozoa and ciliated epithelial cells (at protein level). Expressed specifically in epididymis and testis. Isoform 2 is expressed only in the epididymis. Weak expression is detected in myoid cells as well as spermatogenic cells.

Cellular localization

• Isoform 1
• Secreted
• Cell surface
• Bound to the surface of testicular and on the head and tail of ejaculate spermatozoa.

Alternative names

SPINLW1, WAP7, WFDC7, EPPIN, Eppin, Cancer/testis antigen 71, Epididymal protease inhibitor, Protease inhibitor WAP7, Serine protease inhibitor-like with Kunitz and WAP domains 1, WAP four-disulfide core domain protein 7, CT71

Database links

swissprot:O95925 omim:609031 entrezGene:57119 entrezGene:100526773