Complement component 3 Information & Complement component 3 Links at HealthHaven.com

Complement component 3
	; PDB rendering based on 1c3d.
Available structures
	1c3d, 1ghq, 1w2s, 2a73, 2a74, 2b39, 2gox, 2hr0, 2i07, 2ice, 2icf
Identifiers
Symbols	C3; ASP; CPAMD1
External IDs	OMIM: 120700 MGI: 88227 HomoloGene: 68031 GeneCards: C3 Gene
Gene ontology
Molecular function	• endopeptidase inhibitor activity; • receptor binding;
Cellular component	• extracellular region;
Biological process	• inflammatory response; • complement activation, alternative pathway; • complement activation, classical pathway; • signal transduction; • G-protein coupled receptor protein signaling pathway;
Orthologs

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Complement component 3, often simply called C3, is a protein of the immune system. It plays a central role in the complement system and contributes to innate immunity. In humans it is encoded on chromosome 19 by a gene called C3.^[1]^[2]

[edit] Function

C3 plays a central role in the activation of complement system.^[3] Its activation is required for both classical and alternative complement activation pathways. People with C3 deficiency are susceptible to bacteria infection.^[4]^[5]

Soluble C3-convertase, also known as C4b2a, catalyzes the proteolytic cleavage of C3 into C3a and C3b as part of the classical complement system as well as the mannan-binding lectin pathway. C3a is an anaphylotoxin, and C3b serves as an opsonizing agent. Factor I can cleave C3b into C3c and C3d, the latter of which plays a role in enhancing B cell responses. In the alternative complement pathway, C3 is cleaved by iC3Bb, another form of C3-convertase.

[edit] Structure

Several crystallographic structures of C3 have been determined and reveal that this protein contains 13 domains.^[6]^[7]^[8]^[9]

[edit] Clinical use

Levels of C3 in the blood may be measured to support or refute a particular medical diagnosis. For example, low C3 levels are associated with some types of kidney disease such as post-infectious glomerulonephritis and shunt nephritis.

[edit] Interactions

Complement component 3 has been shown to interact with Factor H.^[10]^[11]

[edit] References

^ de Bruijn MH, Fey GH (February 1985). "Human complement component C3: cDNA coding sequence and derived primary structure". Proc. Natl. Acad. Sci. U.S.A. 82 (3): 708–12. doi:10.1073/pnas.82.3.708. PMID 2579379. PMC 397115. http://www.pnas.org/content/82/3/708.abstract.
^ "Entrez Gene: C3 complement component 3". http://www.ncbi.nlm.nih.gov/sites/entrez?Db=gene&Cmd=ShowDetailView&TermToSearch=718.
^ Sahu A, Lambris JD (April 2001). "Structure and biology of complement protein C3, a connecting link between innate and acquired immunity". Immunol. Rev. 180: 35–48. doi:10.1034/j.1600-065X.2001.1800103.x. PMID 11414361.
^ Lachmann P (December 1975). "Genetics of the complement system". J. Med. Genet. 12 (4): 372–7. doi:10.1136/jmg.12.4.372. PMID 768477.
^ Matsuyama W, Nakagawa M, Takashima H, Muranaga F, Sano Y, Osame M (December 2001). "Molecular analysis of hereditary deficiency of the third component of complement (C3) in two sisters" (^{[dead link]} – ^{Scholar search}). Intern. Med. 40 (12): 1254–8. doi:10.2169/internalmedicine.40.1254. PMID 11813855. http://joi.jlc.jst.go.jp/JST.Journalarchive/internalmedicine1992/40.1254?from=PubMed.
^ Janssen BJ, Huizinga EG, Raaijmakers HC, Roos A, Daha MR, Nilsson-Ekdahl K, Nilsson B, Gros P (September 2005). "Structures of complement component C3 provide insights into the function and evolution of immunity". Nature 437 (7058): 505–11. doi:10.1038/nature04005. PMID 16177781.
^ Janssen BJ, Christodoulidou A, McCarthy A, Lambris JD, Gros P (November 2006). "Structure of C3b reveals conformational changes that underlie complement activity". Nature 444 (7116): 213–6. doi:10.1038/nature05172. PMID 17051160.
^ Wiesmann C, Katschke KJ, Yin J, Helmy KY, Steffek M, Fairbrother WJ, McCallum SA, Embuscado L, DeForge L, Hass PE, van Lookeren Campagne M (November 2006). "Structure of C3b in complex with CRIg gives insights into regulation of complement activation". Nature 444 (7116): 217–20. doi:10.1038/nature05263. PMID 17051150.
^ Fredslund F, Jenner L, Husted LB, Nyborg J, Andersen GR, Sottrup-Jensen L (August 2006). "The structure of bovine complement component 3 reveals the basis for thioester function". J. Mol. Biol. 361 (1): 115–27. doi:10.1016/j.jmb.2006.06.009. PMID 16831446.
^ Soames, C J; Sim R B (Sep. 1997). "Interactions between human complement components factor H, factor I and C3b". Biochem. J. (ENGLAND) 326 ( Pt 2): 553–61. ISSN 0264-6021. PMID 9291131.
^ Jokiranta, T S; Westin J, Nilsson U R, Nilsson B, Hellwage J, Löfås S, Gordon D L, Ekdahl K N, Meri S (Mar. 2001). "Complement C3b interactions studied with surface plasmon resonance technique". Int. Immunopharmacol. (Netherlands) 1 (3): 495–506. ISSN 1567-5769. PMID 11367533.

[edit] External links

MeSH Complement+C3

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This article incorporates text from the United States National Library of Medicine, which is in the public domain.

[pmid2579379-0] Bruijn MH, Fey GH (February 1985). "Human complement component C3: cDNA coding sequence and derived primary structure". Proc. Natl. Acad. Sci. U.S.A. 82 (3): 708–12. doi:10.1073/pnas.82.3.708. PMID 2579379. PMC 397115. http://www.pnas.org/content/82/3/708.abstract.

[entrez_718-1] "Entrez Gene: C3 complement component 3". http://www.ncbi.nlm.nih.gov/sites/entrez?Db=gene&Cmd=ShowDetailView&TermToSearch=718.

[pmid11414361-2] Sahu A, Lambris JD (April 2001). "Structure and biology of complement protein C3, a connecting link between innate and acquired immunity". Immunol. Rev. 180: 35–48. doi:10.1034/j.1600-065X.2001.1800103.x. PMID 11414361.

[pmid768477-3] Lachmann P (December 1975). "Genetics of the complement system". J. Med. Genet. 12 (4): 372–7. doi:10.1136/jmg.12.4.372. PMID 768477.

[pmid11813855-4] Matsuyama W, Nakagawa M, Takashima H, Muranaga F, Sano Y, Osame M (December 2001). "Molecular analysis of hereditary deficiency of the third component of complement (C3) in two sisters" (^{[dead link]} – ^{Scholar search}). Intern. Med. 40 (12): 1254–8. doi:10.2169/internalmedicine.40.1254. PMID 11813855. http://joi.jlc.jst.go.jp/JST.Journalarchive/internalmedicine1992/40.1254?from=PubMed.

[pmid16177781-5] Janssen BJ, Huizinga EG, Raaijmakers HC, Roos A, Daha MR, Nilsson-Ekdahl K, Nilsson B, Gros P (September 2005). "Structures of complement component C3 provide insights into the function and evolution of immunity". Nature 437 (7058): 505–11. doi:10.1038/nature04005. PMID 16177781.

[pmid17051160-6] Janssen BJ, Christodoulidou A, McCarthy A, Lambris JD, Gros P (November 2006). "Structure of C3b reveals conformational changes that underlie complement activity". Nature 444 (7116): 213–6. doi:10.1038/nature05172. PMID 17051160.

[pmid17051150-7] Wiesmann C, Katschke KJ, Yin J, Helmy KY, Steffek M, Fairbrother WJ, McCallum SA, Embuscado L, DeForge L, Hass PE, van Lookeren Campagne M (November 2006). "Structure of C3b in complex with CRIg gives insights into regulation of complement activation". Nature 444 (7116): 217–20. doi:10.1038/nature05263. PMID 17051150.

[pmid16831446-8] Fredslund F, Jenner L, Husted LB, Nyborg J, Andersen GR, Sottrup-Jensen L (August 2006). "The structure of bovine complement component 3 reveals the basis for thioester function". J. Mol. Biol. 361 (1): 115–27. doi:10.1016/j.jmb.2006.06.009. PMID 16831446.

[pmid9291131-9] Soames, C J; Sim R B (Sep. 1997). "Interactions between human complement components factor H, factor I and C3b". Biochem. J. (ENGLAND) 326 ( Pt 2): 553–61. ISSN 0264-6021. PMID 9291131.

[pmid11367533-10] Jokiranta, T S; Westin J, Nilsson U R, Nilsson B, Hellwage J, Löfås S, Gordon D L, Ekdahl K N, Meri S (Mar. 2001). "Complement C3b interactions studied with surface plasmon resonance technique". Int. Immunopharmacol. (Netherlands) 1 (3): 495–506. ISSN 1567-5769. PMID 11367533.

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