COX5B

Cytochrome c oxidase subunit Vb
Identifiers
Aliases	COX5B, cytochrome c oxidase subunit Vb, COXVB
External IDs	HomoloGene: 37538 GeneCards: 1329
Gene ontology Molecular function • cytochrome-c oxidase activity • protein binding • metal ion binding Cellular component • mitochondrial inner membrane • mitochondrial envelope • extracellular exosome • mitochondrion • membrane Biological process • hydrogen ion transmembrane transport • respiratory electron transport chain • transcription initiation from RNA polymerase II promoter • cellular metabolic process • gene expression • small molecule metabolic process • respiratory gaseous exchange Sources:Amigo / QuickGO
RNA expression pattern
More reference expression data
Orthologs
Species	Human	Mouse
Entrez	1329	n/a
Ensembl	ENSG00000135940	n/a
UniProt	P10606	n/a
RefSeq (mRNA)	NM_001862	n/a
RefSeq (protein)	NP_001853.2	n/a
Location (UCSC)	Chr 2: 97.65 – 97.65 Mb	n/a
PubMed search		n/a
Wikidata

View/Edit Human

Cytochrome c oxidase subunit 5B, mitochondrial is an enzyme that in humans is encoded by the COX5B gene. Cytochrome c oxidase 5B is a subunit of the cytochrome c oxidase complex, also known as Complex IV, the last enzyme in the mitochondrial electron transport chain.^[1]

Structure

The COX5B gene, located on the q arm of chromosome 2 in position 11.2, is made up of 4 exons and is 2,137 base pairs in length.^[1] The COX5B protein weighs 14 kDa and is composed of 129 amino acids.^[2][3] The protein is a subunit of Complex IV, which consists of 13 mitochondrial- and nuclear-encoded subunits.^[1]

Function

Cytochrome c oxidase (COX) is the terminal enzyme of the mitochondrial respiratory chain. It is a multi-subunit enzyme complex that couples the transfer of electrons from cytochrome c to molecular oxygen and contributes to a proton electrochemical gradient across the inner mitochondrial membrane to drive ATP synthesis via protonmotive force. The mitochondrially-encoded subunits perform the electron transfer of proton pumping activities. The functions of the nuclear-encoded subunits are unknown but they may play a role in the regulation and assembly of the complex.^[1]

Summary reaction:

4 Fe²⁺-cytochrome c + 8 H⁺_in + O₂ → 4 Fe³⁺-cytochrome c + 2 H₂O + 4 H⁺_out^[4]

Clinical significance

COX5A and COX5B are involved in the regulation of cancer cell metabolism by Bcl-2.^[5]

The Trans-activator of transcription protein (Tat) of human immunodeficiency virus (HIV) inhibits cytochrome c oxidase (COX) activity in permeabilized mitochondria isolated from both mouse and human liver, heart, and brain samples.^[6]

Interactions

COX5B has been shown to interact with Androgen receptor.^[7]

References

1. "Entrez Gene: COX5B cytochrome c oxidase subunit Vb".
2. ]Zong NC, Li H, Li H, Lam MP, Jimenez RC, Kim CS, Deng N, Kim AK, Choi JH, Zelaya I, Liem D, Meyer D, Odeberg J, Fang C, Lu HJ, Xu T, Weiss J, Duan H, Uhlen M, Yates JR, Apweiler R, Ge J, Hermjakob H, Ping P (Oct 2013). "Integration of cardiac proteome biology and medicine by a specialized knowledgebase". Circulation Research 113 (9): 1043–53. doi:10.1161/CIRCRESAHA.113.301151. PMC 4076475. PMID 23965338.
3. "Cytochrome c oxidase subunit 5B, mitochondrial". Cardiac Organellar Protein Atlas Knowledgebase (COPaKB).
4. Pratt, Donald Voet, Judith G. Voet, Charlotte W. (2013). "18". Fundamentals of biochemistry : life at the molecular level (4th ed.). Hoboken, NJ: Wiley. pp. 581–620. ISBN 9780470547847.
5. Chen ZX, Pervaiz S (Mar 2010). "Involvement of cytochrome c oxidase subunits Va and Vb in the regulation of cancer cell metabolism by Bcl-2". Cell Death and Differentiation 17 (3): 408–20. doi:10.1038/cdd.2009.132. PMID 19834492.
6. Lecoeur H, Borgne-Sanchez A, Chaloin O, El-Khoury R, Brabant M, Langonné A, Porceddu M, Brière JJ, Buron N, Rebouillat D, Péchoux C, Deniaud A, Brenner C, Briand JP, Muller S, Rustin P, Jacotot E (2012). "HIV-1 Tat protein directly induces mitochondrial membrane permeabilization and inactivates cytochrome c oxidase". Cell Death & Disease 3: e282. doi:10.1038/cddis.2012.21. PMC 3317353. PMID 22419111.
7. Beauchemin AM, Gottlieb B, Beitel LK, Elhaji YA, Pinsky L, Trifiro MA (2001). "Cytochrome c oxidase subunit Vb interacts with human androgen receptor: a potential mechanism for neurotoxicity in spinobulbar muscular atrophy". Brain Res. Bull. 56 (3-4): 285–97. doi:10.1016/S0361-9230(01)00583-4. PMID 11719263.

Further reading

• Lomax MI, Hsieh CL, Darras BT, Francke U (1991). "Structure of the human cytochrome c oxidase subunit Vb gene and chromosomal mapping of the coding gene and of seven pseudogenes". Genomics 10 (1): 1–9. doi:10.1016/0888-7543(91)90476-U. PMID 1646156.
• Romero N, Marsac C, Fardeau M, Droste M, Schneyder B, Kadenbach B (1990). "Immunohistochemical demonstration of fibre type-specific isozymes of cytochrome c oxidase in human skeletal muscle". Histochemistry 94 (2): 211–5. doi:10.1007/BF02440190. PMID 2162812.
• Zeviani M, Sakoda S, Sherbany AA, Nakase H, Rizzuto R, Samitt CE, DiMauro S, Schon EA (1988). "Sequence of cDNAs encoding subunit Vb of human and bovine cytochrome c oxidase". Gene 65 (1): 1–11. doi:10.1016/0378-1119(88)90411-8. PMID 2840351.
• Hughes GJ, Frutiger S, Paquet N, Pasquali C, Sanchez JC, Tissot JD, Bairoch A, Appel RD, Hochstrasser DF (1993). "Human liver protein map: update 1993". Electrophoresis 14 (11): 1216–22. doi:10.1002/elps.11501401181. PMID 8313870.
• Bachman NJ, Yang TL, Dasen JS, Ernst RE, Lomax MI (1996). "Phylogenetic footprinting of the human cytochrome c oxidase subunit VB promoter". Arch. Biochem. Biophys. 333 (1): 152–62. doi:10.1006/abbi.1996.0376. PMID 8806766.
• Lefai E, Vincent A, Boespflug-Tanguy O, Tanguy A, Alziari S (1997). "Quantitative decrease of human cytochrome c oxidase during development: evidences for a post-transcriptional regulation". Biochim. Biophys. Acta 1318 (1-2): 191–201. doi:10.1016/S0005-2728(96)00136-3. PMID 9030264.
• Wu H, Rao GN, Dai B, Singh P (2000). "Autocrine gastrins in colon cancer cells Up-regulate cytochrome c oxidase Vb and down-regulate efflux of cytochrome c and activation of caspase-3". J. Biol. Chem. 275 (42): 32491–8. doi:10.1074/jbc.M002458200. PMID 10915781.
• Beauchemin AM, Gottlieb B, Beitel LK, Elhaji YA, Pinsky L, Trifiro MA (2002). "Cytochrome c oxidase subunit Vb interacts with human androgen receptor: a potential mechanism for neurotoxicity in spinobulbar muscular atrophy". Brain Res. Bull. 56 (3-4): 285–97. doi:10.1016/S0361-9230(01)00583-4. PMID 11719263.
• Ewing RM, Chu P, Elisma F, Li H, Taylor P, Climie S, McBroom-Cerajewski L, Robinson MD, O'Connor L, Li M, Taylor R, Dharsee M, Ho Y, Heilbut A, Moore L, Zhang S, Ornatsky O, Bukhman YV, Ethier M, Sheng Y, Vasilescu J, Abu-Farha M, Lambert JP, Duewel HS, Stewart II, Kuehl B, Hogue K, Colwill K, Gladwish K, Muskat B, Kinach R, Adams SL, Moran MF, Morin GB, Topaloglou T, Figeys D (2007). "Large-scale mapping of human protein-protein interactions by mass spectrometry". Mol. Syst. Biol. 3 (1): 89. doi:10.1038/msb4100134. PMC 1847948. PMID 17353931.

External links

• Mass spectrometry characterization of COX5B at COPaKB
• Cytochrome c oxidase subunit Vb in PROSITE

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