Complement component 4B

Complement component 4B (Chido blood group) is a protein that in humans is encoded by the C4B gene.[5]

C4B
Available structures PDB Ortholog search: PDBe RCSB List of PDB id codes 1HZF, 4FXG, 4FXK, 4XAM,%%s4XAM
Identifiers
Aliases	C4B, C4B1, C4B12, C4B2, C4B3, C4B5, C4BD, C4B_2, C4F, CH, CO4, CPAMD3, Complement component 4B, complement component 4B (Chido blood group), complement C4B (Chido blood group)
External IDs	OMIM: 120820 MGI: 88228 HomoloGene: 36030 GeneCards: C4B
Gene location (Human) Chr. Chromosome 6 (human)[1] Band 6p21.33 Start 32,014,795 bp[1] End 32,035,418 bp[1]
Gene location (Mouse) Chr. Chromosome 17 (mouse)[2] Band 17 B1|17 18.29 cM Start 34,728,380 bp[2] End 34,743,882 bp[2]
Gene ontology Molecular function • endopeptidase inhibitor activity • complement component C1q binding • serine-type endopeptidase activity • complement binding • carbohydrate binding Cellular component • extracellular region • cell membrane • extracellular exosome • blood microparticle • cell projection • dendrite • cell junction • synapse • axon • neuronal cell body • extracellular • endoplasmic reticulum lumen Biological process • complement activation • inflammatory response • positive regulation of apoptotic cell clearance • regulation of complement activation • negative regulation of endopeptidase activity • Classical complement pathway • immune system process • innate immune system • proteolysis • post-translational modification • cellular protein metabolic process • opsonization Sources:Amigo / QuickGO
Orthologs
Species	Human	Mouse
Entrez	721	12268
Ensembl	ENSG00000228267 ENSG00000236625 ENSG00000224389 ENSG00000228454 ENSG00000224639 n/a	ENSMUSG00000073418
UniProt	P0C0L4 P0C0L5	P01029
RefSeq (mRNA)	NM_001002029	NM_009780
RefSeq (protein)	NP_001239133 NP_009224 NP_001229752	NP_033910
Location (UCSC)	Chr 6: 32.01 – 32.04 Mb	Chr 17: 34.73 – 34.74 Mb
PubMed search	[3]	[4]
Wikidata
View/Edit Human View/Edit Mouse

This gene encodes the basic form of complement factor 4, part of the classical activation pathway. The protein is expressed as a single chain precursor which is proteolytically cleaved into a trimer of alpha, beta, and gamma chains prior to secretion. The trimer provides a surface for interaction between the antigen-antibody complex and other complement components. The alpha chain may be cleaved to release C4 anaphylatoxin, a mediator of local inflammation. Deficiency of this protein is associated with systemic lupus erythematosus. This gene localizes to the major histocompatibility complex (MHC) class III region on chromosome 6. Varying haplotypes of this gene cluster exist, such that individuals may have 1, 2, or 3 copies of this gene. In addition, this gene exists as a long form and a short form due to the presence or absence of a 6.4 kb endogenous HERV-K retrovirus in intron 9. [provided by RefSeq, Jul 2008].[5]

See also

• Complement component 4
  • Complement component 4A
• HLA A1-B8-DR3-DQ2 haplotype
• Complement system
• Complement deficiency

References

1. ENSG00000236625, ENSG00000224389, ENSG00000228454, ENSG00000224639 GRCh38: Ensembl release 89: ENSG00000228267, ENSG00000236625, ENSG00000224389, ENSG00000228454, ENSG00000224639 - Ensembl, May 2017
2. GRCm38: Ensembl release 89: ENSMUSG00000073418 - Ensembl, May 2017
3. "Human PubMed Reference:". National Center for Biotechnology Information, U.S. National Library of Medicine.
4. "Mouse PubMed Reference:". National Center for Biotechnology Information, U.S. National Library of Medicine.
5. "Entrez Gene: Complement component 4B (Chido blood group)". Retrieved 2012-01-27.

Further reading

• Yu CY (1998). "Molecular genetics of the human MHC complement gene cluster". Experimental and Clinical Immunogenetics. 15 (4): 213–30. doi:10.1159/000019075. PMID 10072631.
• Yang Z, Mendoza AR, Welch TR, Zipf WB, Yu CY (Apr 1999). "Modular variations of the human major histocompatibility complex class III genes for serine/threonine kinase RP, complement component C4, steroid 21-hydroxylase CYP21, and tenascin TNX (the RCCX module). A mechanism for gene deletions and disease associations". The Journal of Biological Chemistry. 274 (17): 12147–56. doi:10.1074/jbc.274.17.12147. PMID 10207042.
• Blom AM, Webb J, Villoutreix BO, Dahlbäck B (Jul 1999). "A cluster of positively charged amino acids in the C4BP alpha-chain is crucial for C4b binding and factor I cofactor function". The Journal of Biological Chemistry. 274 (27): 19237–45. doi:10.1074/jbc.274.27.19237. PMID 10383431.
• Tas SW, Klickstein LB, Barbashov SF, Nicholson-Weller A (Nov 1999). "C1q and C4b bind simultaneously to CR1 and additively support erythrocyte adhesion". Journal of Immunology. 163 (9): 5056–63. PMID 10528211.
• Aoki H, Takizawa F, Tsuji S, Nagasawa S (Jul 2000). "Elongation factor-1alpha as a homologous complement activator of Jurkat cells". International Journal of Molecular Medicine. 6 (1): 87–92. doi:10.3892/ijmm.6.1.87. PMID 10851272.
• Teisberg P, Akesson I, Olaisen B, Gedde-Dahl T, Thorsby E (Nov 1976). "Genetic polymorphism of C4 in man and localisation of a structural C4 locus to the HLA gene complex of chromosome 6". Nature. 264 (5583): 253–4. doi:10.1038/264253a0. PMID 1088823.
• Pan Q, Ebanks RO, Isenman DE (Sep 2000). "Two clusters of acidic amino acids near the NH2 terminus of complement component C4 alpha'-chain are important for C2 binding". Journal of Immunology. 165 (5): 2518–27. doi:10.4049/jimmunol.165.5.2518. PMID 10946278.
• Kramer J, Harcos P, Prohászka Z, Horváth L, Karádi I, Singh M, Császár A, Romics L, Füst G (Nov 2000). "Frequencies of certain complement protein alleles and serum levels of anti-heat-shock protein antibodies in cerebrovascular diseases". Stroke: A Journal of Cerebral Circulation. 31 (11): 2648–52. doi:10.1161/01.STR.31.11.2648. PMID 11062289.
• Dragon-Durey MA, Rougier N, Clauvel JP, Caillat-Zucman S, Remy P, Guillevin L, Liote F, Blouin J, Ariey F, Lambert BU, Kazatchkine MD, Weiss L (Jan 2001). "Lack of evidence of a specific role for C4A gene deficiency in determining disease susceptibility among C4-deficient patients with systemic lupus erythematosus (SLE)". Clinical and Experimental Immunology. 123 (1): 133–9. doi:10.1046/j.1365-2249.2001.01438.x. PMC 1905972. PMID 11168010.
• Laich A, Sim RB (Jan 2001). "Complement C4bC2 complex formation: an investigation by surface plasmon resonance". Biochimica et Biophysica Acta (BBA) - Protein Structure and Molecular Enzymology. 1544 (1–2): 96–112. doi:10.1016/S0167-4838(00)00208-9. PMID 11341920.