FITC Mouse Anti-Rat CD45R Antibody (S-3303)

CD45R is a critical splice variant of the CD45 protein, belonging to the receptor-type protein tyrosine phosphatase (RPTP) family. It is primarily expressed on the surface of B cells, monocytes, and certain T cell subsets. As a transmembrane glycoprotein, its extracellular region contains domains (A, B, C) encoded by variable exons, forming diverse isoforms (e.g., CD45RA, CD45RB). These domain variations influence glycosylation patterns and ligand-binding properties. The core function of CD45R lies in its intracellular phosphatase domain, which specifically dephosphorylates the C-terminal inhibitory tyrosine residues of Src family kinases (such as Lck and Fyn). This action positively regulates the initiation and activation threshold of lymphocyte receptor signaling pathways, playing a vital role in B cell development, activation, and the fine-tuning of immune responses. Changes in its expression pattern often serve as markers for lymphocyte differentiation and activation status (e.g., CD45RA+ denotes naive T cells), holding significant value in immunology research and the clinical diagnosis of immune-related diseases.