Complement component C9 (IPR037567)

Short name: Complement_C9

Overlapping homologous superfamilies


Family relationships


This entry represents the complement component C9, which is a component of the membrane attack complex (MAC) which forms pores in the membranes of cells of invading organisms. MAC forms when C5 is cleaved into C5a and C5b, and C5b binds sequentially C6, C7, C8 and multiple copies of the pore-forming subunit C9 [PMID: 22267737]. C9 is the pore-forming subunit of the MAC [PMID: 4055801], and up to twenty subunits assemble to form a large beta barrel that forms a pore with a diameter of 100 angstroms in target membranes [PMID: 26841934]. C9 is processed into a two-chain form, chains C9a and C9b, by thrombin [PMID: 4018030]. The tertiary structure of C9 has been solved and shows the following domains (N- to C-terminal): TSP type-1, LDL-receptor class A, MACPF and EGF-like [PMID: 26841934]. A variant of C9 is associated with macular degeneration of the eye [PMID: 24036952].

GO terms

Biological Process

No terms assigned in this category.

Molecular Function

No terms assigned in this category.

Cellular Component

GO:0005579 membrane attack complex

Contributing signatures

Signatures from InterPro member databases are used to construct an entry.