PTPRK
The PTPRK gene encodes RPTPkappa, a LAR-family receptor-type phosphatase whose ectodomain contains a MAM-like region, an immunoglobulin-like domain, and four fibronectin type III repeats and mediates homophilic cell-cell adhesion. Its single intracellular catalytic domain dephosphorylates substrates including beta-catenin, p120-catenin, and other adherens junction components, connecting phosphatase activity to contact inhibition and cadherin-based adhesion. RPTPkappa is expressed in brain, epithelium, and hematopoietic cells, and it restrains EGFR and Src signaling. Frequent silencing or mutation of PTPRK in lymphomas and solid tumors supports a tumor-suppressor role, and recombinant RPTPkappa proteins are valuable tools for dissecting adhesion-regulated phosphatase signaling.
