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Reliable, easy-to-read patient information on common medical conditions — written in plain language, free of jargon, and grounded in current evidence. Browse the most frequent diagnoses, understand what they mean for everyday life, and learn which steps and questions help you have a focused conversation with your doctor.

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UQCRQ

Introduction

Ubiquinol-cytochrome c reductase, complex III subunit VII, 9.5kDa is a protein that in humans is encoded by the UQCRQ gene. This ubiqinone-binding protein is a subunit of mitochondrial Complex III in the electron transport chain.[1] A mutation in the UQCRQ gene has been shown to cause severe neurological disorders.[2] Infection by Trypanosoma cruzi can cause oxidative modification of this protein in cardiac muscle tissue.[3]

Structure

Structure

The UQCRQ gene is located on the q arm of chromosome 5 in position 31.1 and spans 2,217 base pairs.[4] The gene produces a 9.9 kDa protein composed of 82 amino acids.[5][6] This protein is transmembranous, with more mass on the matrix side of the membrane.[7]

Function

Function

This gene encodes a ubiquinone-binding protein of low molecular mass. It is a small core-associated protein and a subunit of ubiquinol-cytochrome c reductase complex III, which is part of the mitochondrial respiratory chain.[1]

Clinical significance

Clinical significance

Variants of UQCRQ have been associated with complex III deficiency. One set of twenty consanguineous cases of a Ser45Phe mutation in the UQCRQ gene, and a different homozygous 4-bp deletion at p.338-341, have been linked to this disease. In an inbred Israeli Bedouin family, the mutations, inherited in an autosomal recessive pattern, displayed the phenotype of mitochondrial Complex III deficiency, nuclear type 4, accompanied by severe neurological symptoms.[2] Other symptoms of complex III deficiency linked to these mutations have included hypoglycemia, lactic acidosis, and hypotonia.[8]

In another study of cardiac muscle tissue in individuals infected by Trypanosoma cruzi, an oxidative modification of the UQCRQ subunit was present, along with oxidative modification of subunits UQCRC1 and UQCRC2 of the same core complex and UQCRH and CYC1 of the neighboring subcomplex.[3]

Interactions

Interactions

The protein encoded by UQCRQ has protein-protein interactions with UQCRC1, OPTN, ERCC8, GRINL1A, Dctn1, K8.1, XRCC3, PML, RAB7A, HNRNPA1L2, CDC73, NLRP3, HAUS2, TMEM248, and GOLT1B.[9]

References

References

  1. ↑ 1.0 1.1 “Entrez Gene: Ubiquinol-cytochrome c reductase, complex III subunit VII, 9.5kDa”. This article incorporates text from this source, which is in the public domain.
  2. ↑ 2.0 2.1 Barel O, Shorer Z, Flusser H, Ofir R, Narkis G, Finer G, Shalev H, Nasasra A, Saada A, Birk OS (May 2008). “Mitochondrial complex III deficiency associated with a homozygous mutation in UQCRQ”. American Journal of Human Genetics. 82 (5): 1211–6. doi:10.1016/j.ajhg.2008.03.020. PMC 2427202. PMID 18439546.
  3. ↑ 3.0 3.1 Wen JJ, Garg N (December 2004). “Oxidative modification of mitochondrial respiratory complexes in response to the stress of Trypanosoma cruzi infection”. Free Radical Biology & Medicine. 37 (12): 2072–81. doi:10.1016/j.freeradbiomed.2004.09.011. PMID 15544925.
  4. ↑ “Entrez Gene: Ubiquinol-cytochrome c reductase, complex III subunit VII, 9.5kDa”.
  5. ↑ 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 (October 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.
  6. ↑ “UQCRQ – Cytochrome b-c1 complex subunit 8”. Cardiac Organellar Protein Atlas Knowledgebase (COPaKB).
  7. ↑ Usui S, Yu L, Yu CA (May 1990). “The small molecular mass ubiquinone-binding protein (QPc-9.5 kDa) in mitochondrial ubiquinol-cytochrome c reductase: isolation, ubiquinone-binding domain, and immunoinhibition”. Biochemistry. 29 (19): 4618–26. doi:10.1021/bi00471a017. PMID 2164842.
  8. ↑ Haut S, Brivet M, Touati G, Rustin P, Lebon S, Garcia-Cazorla A, Saudubray JM, Boutron A, Legrand A, Slama A (July 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.
  9. ↑ IntAct. “Interactions with UQCRQ”. www.ebi.ac.uk. Retrieved 2018-08-02.
Further reading

Further reading

  • Schägger H, Brandt U, Gencic S, von Jagow G (1995). “Ubiquinol-cytochrome-c reductase from human and bovine mitochondria”. Methods in Enzymology. 260: 82–96. doi:10.1016/0076-6879(95)60132-5. PMID 8592474.
  • Sifroni KG, Damiani CR, Stoffel C, Cardoso MR, Ferreira GK, Jeremias IC, Rezin GT, Scaini G, Schuck PF, Dal-Pizzol F, Streck EL (September 2010). “Mitochondrial respiratory chain in the colonic mucosal of patients with ulcerative colitis”. Molecular and Cellular Biochemistry. 342 (1–2): 111–5. doi:10.1007/s11010-010-0474-x. PMID 20440543.

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