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Ubiquinol-cytochrome c reductase binding protein
External IDs OMIM191330 MGI3646665 HomoloGene38164 ChEMBL: 1671612 GeneCards: UQCRB Gene
EC number
Species Human Mouse
Entrez 7381 67530
Ensembl ENSG00000156467 ENSMUSG00000021520
UniProt P14927 Q9D855
RefSeq (mRNA) NM_001199975 NM_026219
RefSeq (protein) NP_001186904 NP_080495
Location (UCSC) Chr 8:
97.24 – 97.25 Mb
Chr 13:
66.9 – 66.91 Mb
PubMed search [1] [2]

Ubiquinol-cytochrome c reductase binding protein, also known as UQCRB, is a protein which in humans is encoded by the UQCRB gene.[1]


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. Complex III consists of 10 nuclear-encoded subunits and 1 mitochondrial-encoded subunit.[1]

UQCRB is a subunit of the respiratory chain protein Ubiquinol Cytochrome c Reductase (UQCR, Complex III or Cytochrome bc1 complex), which consists of the products of one mitochondrially encoded gene:

and ten nuclear genes:

After processing the cleaved leader sequence of the iron-sulfur protein is retained as subunit 9, giving 11 subunits from 10 genes.

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 going from Laemli gels to Weber&Osborne gels, and one might suspect the name "Q-binding protein" arose from confusion with subunit 7. I have been told however that this is not the case, and both proteins were separately identified as Q-binding proteins. Genome anotators improved the situation by naming its gene "UQCR binding", UQCRB.


Further reading[edit]

  • Suzuki H, Hosokawa Y, Toda H et al. (1990). "Common protein-binding sites in the 5'-flanking regions of human genes for cytochrome c1 and ubiquinone-binding protein.". J. Biol. Chem. 265 (14): 8159–63. PMID 2159470. 
  • Hosokawa Y, Suzuki H, Nishikimi M et al. (1990). "Chromosomal assignment of the gene for the ubiquinone-binding protein of human mitochondrial cytochrome bc1 complex.". Biochem. Int. 21 (1): 41–4. PMID 2167087. 
  • Suzuki H, Hosokawa Y, Toda H et al. (1989). "Isolation of a single nuclear gene encoding human ubiquinone-binding protein in complex III of mitochondrial respiratory chain.". Biochem. Biophys. Res. Commun. 161 (1): 371–8. doi:10.1016/0006-291X(89)91607-0. PMID 2543413. 
  • Wakabayashi S, Takao T, Shimonishi Y et al. (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.". J. Biol. Chem. 260 (1): 337–43. PMID 2981208. 
  • Suzuki H, Hosokawa Y, Toda H et al. (1988). "Cloning and sequencing of a cDNA for human mitochondrial ubiquinone-binding protein of complex III.". Biochem. Biophys. Res. Commun. 156 (2): 987–94. doi:10.1016/S0006-291X(88)80941-0. PMID 3056408. 
  • Malaney S, Heng HH, Tsui LC et al. (1996). "Localization of the human gene encoding the 13.3-kDa subunit of mitochondrial complex III (UQCRB) to 8q22 by in situ hybridization.". Cytogenet. Cell Genet. 73 (4): 297–9. doi:10.1159/000134360. PMID 8751380. 
  • Strausberg RL, Feingold EA, Grouse LH et al. (2003). "Generation and initial analysis of more than 15,000 full-length human and mouse cDNA sequences.". Proc. Natl. Acad. Sci. U.S.A. 99 (26): 16899–903. doi:10.1073/pnas.242603899. PMC 139241. PMID 12477932. 
  • Haut S, Brivet M, Touati G et al. (2003). "A deletion in the human QP-C gene causes a complex III deficiency resulting in hypoglycaemia and lactic acidosis.". Hum. Genet. 113 (2): 118–22. doi:10.1007/s00439-003-0946-0. PMID 12709789. 
  • Gerhard DS, Wagner L, Feingold EA et al. (2004). "The status, quality, and expansion of the NIH full-length cDNA project: the Mammalian Gene Collection (MGC).". Genome Res. 14 (10B): 2121–7. doi:10.1101/gr.2596504. PMC 528928. PMID 15489334. 
  • Rual JF, Venkatesan K, Hao T et al. (2005). "Towards a proteome-scale map of the human protein-protein interaction network.". Nature 437 (7062): 1173–8. doi:10.1038/nature04209. PMID 16189514.