A protein that is a translation product of the human PTPRC gene or a 1:1 ortholog thereof. It is composed of an extracellular domain, a single transmembrane segment and two tandem intracytoplasmic protein-tyrosine phosphatase domains. Contains 1 to 3 copies of the Fibronectin type III domain (Pfam:PF00041) followed by two copies of the Protein-tyrosine phosphatase (Pfam:PF00102) domain. Receptor-type tyrosine-protein phosphatase C (CD45) regulates signal transduction and lymphocyte activation by specific association with receptor molecules on T and B cells. Multiple isoforms of CD45 (180-235 kDa) can be generated asa result of alternative splicing of three variable exons 4(A), 5(B) and 6(C), encoding sequences at the N-terminal extracellular domain of the molecule. [ PRO:CNA http://www.ncbi.nlm.nih.gov/pubmed/1351092 ]