Phosphatase Subfamily PTPRC
Phosphatase Classification: Fold CC1: Superfamily CC1: Family PTP: Subfamily PTPRC
PTPRC (CD45) is a vertebrate-specific receptor PTP involved in immune signaling.
Evolution
PTPRC is found as a single-copy gene in all vertebrates, including the lamprey, but not in any invertebrate.
Domain
PTPRC has twin intracellular PTP phosphatase domains, and extracellular FN3 domains, plus a CD45-specific and a PTP-N-terminal domain found specifically in PTPRC, as annotated by InterPro. CD45 is extensively alternatively spliced.
Second phosphatase domain (D2) is inactive
The functional role of the D2 domain has not yet been defined although possible roles in regulating RPTP stability, specificity, and dimerization have been suggested [1].
Functions
CD45 modulates immune function [2]. It is selectively expressed on lymphocytes and dephosphorylates and activates the src family tyrosine kinases lck, fyn and lyn in B and T cells.
Miscellaneous
PTPRC (CD45) is used in CellSearch system to detect circulating tumor cell.
