The protein encoded by this gene contains four kringle domains and a serine protease domain, similar to that found in hepatic growth factor. Despite the presence of the serine protease domain, the encoded protein may not have any proteolytic activity. The receptor for this protein is RON tyrosine kinase, which upon activation stimulates ciliary motility of ciliated epithelial lung cells. This protein is secreted and cleaved to form an alpha chain and a beta chain bridged by disulfide bonds. [provided by RefSeq, Jan 2010]
Expression regulated by
Shigemasa K, et al. reported that The mRNA expression level of p16 was significantly elevated in 28 ovarian tumors (22 carcinomas, five low malignant potential tumors, and one benign tumor) compared with that of normal ovaries. Western blotting analysis and immunohistochemical staining confirmed elevated p16 protein levels in ovarian tumor samples. Among 32 ovarian tumors, cDNA sequencing of the p16 gene showed no p16 mutation resulting in a coding error, although one silent mutation and three polymorphisms were found. Although p16 is seldom mutated in ovarian tumors, the overexpression of p16 in most ovarian tumor cases indicates a dysfunction in the regulatory complex for G1 arrest. Therefore, overexpression of p16 may be an important early event in the neoplastic transformation of the ovarian epithelium.