WAP four-disulfide core domain protein 6 (EPPIN-WFDC6 readthrough) (EPPIN-WFDC6)

EPPIN-WFDC6 is a fusion protein resulting from read-through transcription of the neighboring SPINLW1 (serine peptidase inhibitor-like, with Kunitz and WAP domains 1) and WFDC6 (WAP four-disulfide core domain 6) genes, located on human chromosome 20[1][3][5]. This protein contains a WAP-type four-disulfide core domain, characterized by eight cysteines forming four disulfide bonds, endowing it with protease inhibitor activity essential for sperm maturation, motility regulation, and protection in the male reproductive tract—especially in the epididymis and seminal vesicles[1][3]. EPPIN-WFDC6 supports antimicrobial defense in the ejaculate and modulates hydrolysis of seminal proteins, notably semenogelin 1 through PSA/KLK3 action, which is crucial for male fertility. Like other WFDC domain proteins, it probably participates in broader innate immune defense functions, including antibacterial, antiviral, and immunomodulatory effects, and may have evolving roles in inflammation, infection, or reproductive disease, though direct therapeutic targeting or disease association remains limited[1][2][3][5].

Other names

EPPIN-WFDC6EPPIN-WFDC6 ReadthroughSPINLW1-WFDC6 ReadthroughSPINLW1-WFDC6WAP four-disulfide core domain protein 6WFDC6WAP four-disulfide core domain protein 7Putative protease inhibitor WAP6Epididymal protease inhibitorSerine protease inhibitor-like with Kunitz and WAP domains 1C20orf171WAP6WAP7CT71Cancer/testis antigen 71SPINLW1-WFDC6 fusion proteinSPINLW1-WFDC6 read-through transcript[3][5]

Protein/inhibitor mechanism: Binds semenogelin 1 and KLK3/PSA, regulating proteolytic cleavage essential for sperm function and antimicrobial protection[3]. No small molecule mechanisms documented for pharmaceutical targeting.