C3 (complement)

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complement component 3
Identifiers
Symbol(s)	C3
Entrez	718
OMIM	120700
RefSeq	NM_000064
UniProt	P01024
Other data
EC number	3.4.21.43
Locus	Chr. 19 p13.3-13.2

In immunology, soluble C3-convertase, also known as iC3Bb, catalyzes the proteolytic cleavage of C3 into C3a and C3b as part of the alternative complement system. C3b may then bind to microbal cell surfaces within an organisms body. This can lead to the production of surface-bound C3 convertase and thus more C3b components. Also know as C3bBb, this convertase similar to soluble C3-convertase except that it is membrane bound. Alternatively, binded C3b may aid in opsonization of the microbe by macrophages. Complement receptor 1 or CR1 on macrophages allows the engaging of C3b covered microbes.

[edit] See also

• Complement system

[edit] External links

• Structure and biology of complement protein C3, a connecting link between innate and acquired immunity; Recent review article
• domain structure; protein database
• complete structure; protein database
• complete structure; protein database
• The Structure of Bovine Complement Component 3 Reveals the Basis for Thioester Function; Structure Article

Complement system - edit
Activators: C6 | C7 | C9 | MBL2 | PFC Complexes: C1Q (C1QA, C1QB, C1QG) | C3-convertase | C8 (C8A, C8B, C8G) | MAC Enzymes: BF | C1R | C1S | C2 | C3 | C4 | C5 | DF | MASP1 | MASP2 Inhibitors: C1inh | C4BP (C4BPA, C4BPB) | CLU | DAF | HF1 | IF | SERPING1 | VTN Receptors: C3AR1 | C5R1 | CR1 | CR2 | ITGAM