PTP domain of receptor-type tyrosine-protein phosphatase K, repeat 2
Receptor-type tyrosine-protein phosphatase K (PTPRK), also known as receptor-type tyrosine-protein phosphatase kappa (RPTP-kappa or PTPkappa), belongs to the type IIb subfamily of receptor protein tyrosine phosphatases (RPTPs), which belong to the larger family of classical tyrosine-specific protein tyrosine phosphatases (PTPs). PTPs (EC 3.1.3.48) catalyze the dephosphorylation of phosphotyrosine peptides. PTPRK is widely expressed and has been shown to stimulate cell motility and neurite outgrowth. It is required for anti-proliferative and pro-migratory effects of TGF-beta, suggesting a role in regulation, maintenance, and restoration of cell adhesion. It is a potential tumour suppressor in primary central nervous system lymphomas, colorectal cancer, and breast cancer. It contains an extracellular region with an Meprin-A5 (neuropilin)-mu (MAM) domain, an immunoglobulin (Ig) domain, and four fibronectin type III (FN3) repeats, a transmembrane domain, and an intracellular segment with a juxtamembrane domain similar to the cytoplasmic domain of classical cadherins and two tandem PTP domains. This model represents the second (repeat 2) PTP domain.
Feature 1: catalytic site [active site], 2 residue positions
Conserved feature residue pattern:C R
Evidence:
Comment:the catalytic cysteine initiates a nucleophilic attack on the phosphate group of the substrate, forming a transient phosphoenzyme intermediate and releasing the substrate dephosphorylated; the transition state is stabilized by the arginine present in the catalytic pocket
Jiyao W et al.(2023). "The conserved domain database in 2023.",