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. 188.8.131.52), 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, "11kDa 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 184.108.40.206) in the mitochondrial respiratory chain and plays an important role in electron transfer as a complex of ubiquinone and QP-C.
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.
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 Chemistry265 (14): 8159–63. PMID2159470.
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 International21 (1): 41–4. PMID2167087.
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 Communications161 (1): 371–8. doi:10.1016/0006-291X(89)91607-0. PMID2543413.
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 Chemistry260 (1): 337–43. PMID2981208.
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 Communications156 (2): 987–94. doi:10.1016/S0006-291X(88)80941-0. PMID3056408.
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 Genetics73 (4): 297–9. doi:10.1159/000134360. PMID8751380.
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 Genetics113 (2): 118–22. doi:10.1007/s00439-003-0946-0. PMID12709789.
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". Nature437 (7062): 1173–8. doi:10.1038/nature04209. PMID16189514.