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Aliases UQCRB, MC3DN3, QCR7, QP-C, QPC, UQBC, UQBP, UQCR6, UQPC, ubiquinol-cytochrome c reductase binding protein
External IDs MGI: 1914780 HomoloGene: 38164 GeneCards: 7381
Species Human Mouse
RefSeq (mRNA)



RefSeq (protein)



Location (UCSC) Chr 8: 96.23 – 96.24 Mb Chr 13: 66.9 – 66.91 Mb
PubMed search [1] [2]
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Ubiquinol-cytochrome c reductase binding protein, also known as UQCRB, is a protein which in humans is encoded by the UQCRB gene.[1]


The gene product of UQCRB is a subunit of the respiratory chain protein Ubiquinol Cytochrome c Reductase (UQCR, Complex III or Cytochrome bc1 complex; E.C., which consists of the products of one mitochondrially encoded gene, MTCYTB (mitochondrial cytochrome b) and ten nuclear genes: UQCRC1, UQCRC2, Cytochrome c1, UQCRFS1 (Rieske protein), UQCRB, "14kDa protein", UQCRH (cyt c1 Hinge protein), Rieske Protein presequence, "cyt. c1 associated protein", and "Rieske-associated protein". After processing, the cleaved leader sequence of the iron-sulfur protein is retained as subunit 9, giving 11 subunits from 10 genes.


The ubiquinone-binding protein is a nucleus-encoded component of ubiquinol-cytochrome c oxidoreductase (Complex III; EC in the mitochondrial respiratory chain and plays an important role in electron transfer as a complex of ubiquinone and QP-C.[1]

The bovine gene product (subunit 6) was sequenced under the name "ubiquinone-binding protein", however there is little or no evidence for a role in ubiquinone binding. Subunit 7 was identified as a Q-binding protein by photo-labeling with a ubiquinone analog (subsequent structures show it to be exposed to the lipid phase but not involved in either Q-binding site). Subunits 6 and 7 reverse position on transfer from Laemli gels to Weber&Osborne gels, and one might suspect the name "Q-binding protein" arose from confusion with subunit 7. However, it has been claimed that both proteins were separately identified as Q-binding proteins. Genome annotators improved the situation by naming this gene "UQCR binding", or UQCRB.


Further reading[edit]

  • Suzuki H, Hosokawa Y, Toda H, Nishikimi M, Ozawa T (May 1990). "Common protein-binding sites in the 5'-flanking regions of human genes for cytochrome c1 and ubiquinone-binding protein". The Journal of Biological Chemistry 265 (14): 8159–63. PMID 2159470. 
  • Hosokawa Y, Suzuki H, Nishikimi M, Matsukage A, Yoshida MC, Ozawa T (1990). "Chromosomal assignment of the gene for the ubiquinone-binding protein of human mitochondrial cytochrome bc1 complex". Biochemistry International 21 (1): 41–4. PMID 2167087. 
  • Suzuki H, Hosokawa Y, Toda H, Nishikimi M, Ozawa T (May 1989). "Isolation of a single nuclear gene encoding human ubiquinone-binding protein in complex III of mitochondrial respiratory chain". Biochemical and Biophysical Research Communications 161 (1): 371–8. doi:10.1016/0006-291X(89)91607-0. PMID 2543413. 
  • Wakabayashi S, Takao T, Shimonishi Y, Kuramitsu S, Matsubara H, Wang T, Zhang Z, King TE (Jan 1985). "Complete amino acid sequence of the ubiquinone binding protein (QP-C), a protein similar to the 14,000-dalton subunit of the yeast ubiquinol-cytochrome c reductase complex". The Journal of Biological Chemistry 260 (1): 337–43. PMID 2981208. 
  • Suzuki H, Hosokawa Y, Toda H, Nishikimi M, Ozawa T (Oct 1988). "Cloning and sequencing of a cDNA for human mitochondrial ubiquinone-binding protein of complex III". Biochemical and Biophysical Research Communications 156 (2): 987–94. doi:10.1016/S0006-291X(88)80941-0. PMID 3056408. 
  • Malaney S, Heng HH, Tsui LC, Shi XM, Robinson BH (1996). "Localization of the human gene encoding the 13.3-kDa subunit of mitochondrial complex III (UQCRB) to 8q22 by in situ hybridization". Cytogenetics and Cell Genetics 73 (4): 297–9. doi:10.1159/000134360. PMID 8751380. 
  • Haut S, Brivet M, Touati G, Rustin P, Lebon S, Garcia-Cazorla A, Saudubray JM, Boutron A, Legrand A, Slama A (Jul 2003). "A deletion in the human QP-C gene causes a complex III deficiency resulting in hypoglycaemia and lactic acidosis". Human Genetics 113 (2): 118–22. doi:10.1007/s00439-003-0946-0. PMID 12709789. 
  • Rual JF, Venkatesan K, Hao T, Hirozane-Kishikawa T, Dricot A, Li N, Berriz GF, Gibbons FD, Dreze M, Ayivi-Guedehoussou N, Klitgord N, Simon C, Boxem M, Milstein S, Rosenberg J, Goldberg DS, Zhang LV, Wong SL, Franklin G, Li S, Albala JS, Lim J, Fraughton C, Llamosas E, Cevik S, Bex C, Lamesch P, Sikorski RS, Vandenhaute J, Zoghbi HY, Smolyar A, Bosak S, Sequerra R, Doucette-Stamm L, Cusick ME, Hill DE, Roth FP, Vidal M (Oct 2005). "Towards a proteome-scale map of the human protein-protein interaction network". Nature 437 (7062): 1173–8. doi:10.1038/nature04209. PMID 16189514. 

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