Complement receptor type 1 (CR1) (CR1)

Complement receptor type 1 (CR1), also known as CD35 or the C3b/C4b receptor, is a large transmembrane glycoprotein that serves as a critical regulator and receptor within the complement system. It is primarily expressed on the surface of erythrocytes, where it facilitates the transport and clearance of opsonized immune complexes to the liver and spleen, as well as on various leukocytes and glomerular podocytes. CR1 binds to the complement components C3b, C4b, and C1q, and it exerts its regulatory function by accelerating the decay of C3 and C5 convertases and acting as a cofactor for Factor I in the degradation of C3b and C4b. Genetic polymorphisms in the CR1 gene are significantly associated with the risk of late-onset Alzheimer's disease, likely due to its role in the clearance of amyloid-beta from the circulation. Therapeutically, soluble versions of CR1 (sCR1) have been developed as potent complement inhibitors for treating conditions characterized by excessive complement activation, such as C3 glomerulopathy, transplant rejection, and ischemia-reperfusion injury.

Other names

CD35C3b/C4b receptorKnops blood group antigenComplement receptor 1

Inhibition of the complement cascade by accelerating the decay of C3 and C5 convertases and acting as a cofactor for Factor I-mediated proteolytic cleavage of C3b and C4b.