CD55
Description
The CD55 (CD55 molecule (Cromer blood group)) is a protein-coding gene located on chromosome 1.
CD55, also known as DAF, is a protein that regulates the complement system on the cell surface. It recognizes C4b and C3b fragments generated during complement activation. By interacting with these fragments, CD55 prevents the formation of the C3-convertase and the C3 convertase, thus limiting the amplification of the complement cascade and indirectly blocking the formation of the membrane attack complex. CD55 is a glycoprotein found on various cells, including those of the blood and other tissues. It is also a determinant for the Cromer blood group system. CD55 is a 70 kDa membrane protein attached to the cell membrane via a GPI anchor. It consists of four complement control protein (CCP) repeats, with a glycan positioned between CCP1 and CCP2. CCP2, CCP3, CCP4, and three lysine residues in a positively charged pocket between CCP2 and CCP3 are involved in inhibiting the alternate complement pathway.
CD55, also known as DAF, regulates the complement system by interacting with C4b and C3b fragments, preventing the formation of C3 and C5 convertases, thus inhibiting complement activation and preventing complement damage.
CD55 is also known as CHAPLE, CR, CROM, DAF, TC.
Associated Diseases
- Complement hyperactivation, angiopathic thrombosis, and protein-losing enteropathy
- Blood group, cromer system
