The PTPN12 gene encodes a phosphatase enzyme that is responsible for specifically dephosphorylating tyrosine-phosphorylated proteins. As tyrosine phosphorylation-mediated signaling is responsible for several processes such as cell proliferation, differentiation and mitosis, the PTPN12 enzyme plays a key regulatory role. It is involved in the negative regulation of the ERBB signaling pathway by dephosphorylating the cellular tyrosine kinase ERBB2. Other targets of PTPN12 include proteins related to cell adhesion and the cytoskeleton, thus suggesting a role in maintaining the cellular structure and mobility.
Interestingly, PTPN12 has also been found to dephosphorylate the product of the oncogene c-ABL, indicating a possible role in oncogenesis. Studies have in fact found a mutation in the PTPN12 gene associated with Colorectal Cancer, a heterogeneous somatic carcinoma affecting both men and women.