Complement receptor 1 (CR1)

Complement receptor 1 (CR1), also known as C3b/C4b receptor or CD35, is a type I transmembrane glycoprotein that plays a crucial role in the regulation of the complement cascade and immune complex clearance. It is expressed on various immune cells, erythrocytes, and glomerular podocytes. CR1 acts as a negative regulator of the complement system by binding to C3b and C4b, leading to decay acceleration and cofactor activity, ultimately inhibiting complement activation. Erythrocyte-bound CR1 facilitates immune complex clearance by transporting them to the liver and spleen for removal. Altered expression or mutations in CR1 are associated with several diseases, including systemic lupus erythematosus, malaria, and Alzheimer's disease. Engineered derivatives or soluble forms of CR1 are being explored as potential therapeutics for inhibiting unwanted complement activity.

Other names

C3b/C4b receptorCD35 (Cluster of Differentiation 35)

Engineered derivatives or soluble forms of CR1 are being explored therapeutically to inhibit unwanted complement activity while preserving host defense mechanisms. Smaller but potent inhibitors based on structure-function studies have been developed.