The C8G gene (C8G stands for "Complement C8 Gamma Chain") is a protein coding gene located on chromosome 9q34.3.
The protein encoded by the C8G gene belongs to the lipocalin family. It is one of the three subunits of complement component 8 (C8), which is composed of a disulfide-bound C8-alpha-gamma heterodimer and a non-covalently associated C8-beta chain.
C8 is involved in the formation of the membrane attack complex (MAC) on bacterial cell membranes. While the alpha and beta subunits play a role in complement-mediated killing of bacteria, the gamma subunit is not required for bactericidal activity.
Diseases associated with C8G include immunodeficiencydue to a late component of complement deficiency.
C8 is a component of the membrane attack complex. C8 binds to the C5B-7 complex to form the C5B-8 complex. C5-B8 binds C9 and acts as a catalyst in the polymerization of C9. The gamma subunit appears to be able to bind retinol.