WAP Four Disulfide Core Domain Protein 13 (WFDC13)

WFDC13 encodes a member of the WAP-type four-disulfide core (WFDC) domain family. The WFDC domain, or WAP signature motif, contains eight cysteines forming four disulfide bonds at the core of the protein, and functions as a protease inhibitor. Most WFDC gene members are localized to chromosome 20q12-q13 in two clusters: centromeric and telomeric. This gene belongs to the telomeric cluster. Characteristic features of the genes are that the upstream promoter regions are devoid of TATA-boxes and that the coding nucleotides are divided into distinct exons for the signal peptide and for each WAP domain. In most cases, there is also a separate exon encompassing a few terminal codons and the 3' untranslated nucleotides. There are also examples of mixed type inhibitors, that encode inhibitor domains of both WAP and Kunitz types.