catalytic domain of receptor-type tyrosine-protein phosphatase C, repeat 1
Receptor-type tyrosine-protein phosphatase C (PTPRC), also known as CD45, leukocyte common antigen (LCA) or GP180, belongs to the family of classical tyrosine-specific protein tyrosine phosphatases (PTPs). PTPs (EC 3.1.3.48) catalyze the dephosphorylation of phosphotyrosine peptides. PTPRC/CD45 is found in all nucleated hematopoietic cells and is an essential regulator of T- and B-cell antigen receptor signaling. It controls immune response, both positively and negatively, by dephosphorylating a number of signaling molecules such as the Src family kinases, the CD3zeta chain of TCY, and ZAP-70 kinase. Mutations in the human PTPRC/CD45 gene are associated with severe combined immunodeficiency (SCID) and multiple sclerosis. PTPRC/CD45 contains an extracellular receptor-like region with fibronectin type III (FN3) repeats, a short transmembrane segment, and a cytoplasmic region comprising of a membrane proximal catalytically active PTP domain (repeat 1 or D1) and a membrane distal catalytically impaired PTP-like domain (repeat 2, or D2). This model represents repeat 1.
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.",