PTPRK Gene - Protein Tyrosine Phosphatase Receptor Type K

PTPRK encodes a member of the receptor-type protein tyrosine phosphatase (RPTP) family. The protein contains an extracellular region with MAM, Ig-like, and fibronectin type III domains, a single transmembrane segment, and two tandem cytoplasmic phosphatase domains. It functions as a homophilic cell adhesion molecule and dephosphorylates substrates such as EGFR, STAT3, and β-catenin, thereby regulating cell proliferation, migration, and adhesion. PTPRK is considered a tumor suppressor in several cancers, including colorectal, breast, and lymphoma.

Tissue Expression

Cell Line Expression

Hotspot Mutations

Mutation functional classification

• EGFR tyrosine kinase inhibitor resistance (Reactome: R-HSA-5637815)

• Signaling by Receptor Tyrosine Kinases (Reactome: R-HSA-9006934)

• Cell junction organization (Reactome: R-HSA-446728)

PTPRK is a transmembrane receptor-type protein tyrosine phosphatase that mediates homophilic cell-cell adhesion and negatively regulates growth factor signaling by dephosphorylating key substrates such as EGFR, STAT3, and β-catenin. Its extracellular region contains MAM, Ig-like, and fibronectin type III domains, while the cytoplasmic region harbors two phosphatase domains (D1 catalytic, D2 regulatory). Loss of PTPRK expression or function is associated with multiple cancers, supporting its role as a tumor suppressor.