2rd7

Structural highlights

Disease

[CO8A_HUMAN] Defects in C8A are a cause of complement component 8 deficiency type 1 (C8D1) [MIM:613790]. A rare defect of the complement classical pathway associated with susceptibility to severe recurrent infections, predominantly by Neisseria gonorrhoeae or Neisseria meningitidis.

Function

[CO8A_HUMAN] Constituent of the membrane attack complex (MAC) that plays a key role in the innate and adaptive immune response by forming pores in the plasma membrane of target cells. C8A inserts into the target membrane, but does not form pores by itself.^{[1] [2]} [CO8G_HUMAN] C8 is a constituent of the membrane attack complex. C8 binds to the C5B-7 complex, forming the C5B-8 complex. C5-B8 binds C9 and acts as a catalyst in the polymerization of C9. The gamma subunit seems to be able to bind retinol.

Evolutionary Conservation

Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf.

References

1. ↑ Steckel EW, York RG, Monahan JB, Sodetz JM. The eighth component of human complement. Purification and physicochemical characterization of its unusual subunit structure. J Biol Chem. 1980 Dec 25;255(24):11997-2005. PMID:7440581
2. ↑ Hadders MA, Beringer DX, Gros P. Structure of C8alpha-MACPF reveals mechanism of membrane attack in complement immune defense. Science. 2007 Sep 14;317(5844):1552-4. PMID:17872444 doi:317/5844/1552