CD45s

CD45, also known as protein tyrosine phosphatase, receptor type C (PTPRC), is a protein that plays a crucial role in the immune system. It is a transmembrane protein found on the surface of all hematopoietic cells, excluding erythrocytes and platelets. CD45 is a member of the protein tyrosine phosphatase family and is involved in regulating various signaling pathways within immune cells.

The primary function of CD45 is to dephosphorylate tyrosine residues on other proteins, thereby modulating intracellular signaling cascades. This dephosphorylation is critical for the activation and differentiation of lymphocytes, including T cells and B cells. CD45 acts as a co-receptor, working in conjunction with antigen-specific receptors to amplify signals required for immune cell activation. Its presence is essential for proper immune responses.

Different isoforms of CD45 exist due to alternative splicing of its messenger RNA. These isoforms are expressed in a lineage- and differentiation-specific manner, allowing for distinct functional roles within the immune system. For example, certain isoforms are predominantly found on immature lymphocytes, while others are characteristic of mature immune cells. The expression pattern of CD45 can also be altered in various immune-related diseases, making it a potential biomarker. Research continues to explore the complex roles of CD45 in both normal immune function and disease pathogenesis.