CD45 (PTPRC) is a family of high-molecular weight glycoproteins uniquely expressed on the surface of all leukocytes and their hematopoietic progenitors. The CD45 family consists of multiple members that are all products of a single gene. Structurally, CD45 is composed of one fibronectin extracellular domain, one transmembrane domain, and two cytoplasmic tyrosine phosphatase domains. It is essential for B- and T-cell activation. For both cell-types, CD45 has been shown to interact with kinases including Lyn, src family kinase Lck, and Janus-family kinases. In T cells, CD45 is required for the initiation of receptor signaling by dephosphorylating a negative regulatory tyrosine in the C-terminal tail of Lck. CD45 may also negatively regulate Lck by dephosphorylating the tyrosine in the activation loop, thereby attenuating Lck activity.
Intended for research use only. Not for use in human, therapeutic, or diagnostic applications.