WAP, Follistatin/Kazal, Immunoglobulin, Kunitz And Netrin Domain Containing Protein 1 (WFIKKN1)

WFIKKN1 encodes a secreted multidomain protein consisting of a signal peptide, a WAP domain, a follistatin domain, an immunoglobulin domain, two tandem Kunitz domains, and an NTR domain. These domains have been implicated frequently in inhibition of various types of proteases, suggesting that the encoded protein may be a multivalent protease inhibitor and may control the action of multiple types of serine proteases as well as metalloproteinases.

The deduced 548-amino acid protein contains an N-terminal secretory signal sequence, followed by a WAP 4-disulfide core domain, a cysteine-rich follistatin module of the Kazal type, an immunoglobulin (Ig) domain, 2 tandem Kunitz-type protease inhibitor modules, and an NTR domain near the C terminus.