Protein tyrosine phosphatase receptor type C (PTPRC or CD45)

The leucocyte common antigen, protein tyrosine phosphatase receptor type C (PTPRC), also known as CD45, is a transmembrane glycoprotein, expressed on almost all haematopoietic cells except for mature erythrocytes, and is an essential regulator of T and B cell antigen receptor-mediated activation. Disruption of the equilibrium between protein tyrosine kinase and phosphatase activity (from CD45 and others) can result in immunodeficiency, autoimmunity, or malignancy. CD45 is normally present on the cell surface, therefore it works upstream of a large signalling network which differs between cell types, and thus the effects of CD45 on these cells are also different. However, it is becoming clear that CD45 plays an essential role in the innate immune system and this is likely to be a key area for future research. In this review of PTPRC (CD45), its structure and biological activities as well as abnormal expression of CD45 in leukaemia and lymphoma will be discussed.

Automated summary

CD45, also known as PTPRC, is a transmembrane glycoprotein expressed on almost all haematopoietic cells and plays a crucial role in regulating T and B cell antigen receptor-mediated activation. Imbalance in protein tyrosine kinase and phosphatase activity from CD45 and other proteins can lead to immunodeficiency, autoimmunity, or malignancy. CD45 functions upstream of a large signalling network which varies between cell types, indicating different effects on these cells. Its involvement in the innate immune system highlights the importance of CD45 in future research.