View source for Succinate dehydrogenase complex subunit C

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{{Short description|Protein found in humans}}
{{Infobox gene}}

'''Succinate dehydrogenase complex subunit C''', also known as '''succinate dehydrogenase cytochrome b560 subunit, mitochondrial''', is a [[protein]] that in humans is encoded by the ''SDHC'' [[gene]].<ref name="pmid9533030">{{cite journal | vauthors = Hirawake H, Taniwaki M, Tamura A, Kojima S, Kita K | title = Cytochrome b in human complex II (succinate-ubiquinone oxidoreductase): cDNA cloning of the components in liver mitochondria and chromosome assignment of the genes for the large (SDHC) and small (SDHD) subunits to 1q21 and 11q23 | journal = Cytogenetics and Cell Genetics | volume = 79 | issue = 1–2 | pages = 132–8 | year = 1997 | pmid = 9533030 | doi = 10.1159/000134700 }}</ref> This gene encodes one of four nuclear-encoded subunits that comprise [[succinate dehydrogenase]], also known as mitochondrial complex II, a key enzyme complex of the [[tricarboxylic acid cycle]] and [[electron transport chain|aerobic respiratory chains]] of mitochondria. The encoded protein is one of two integral [[membrane proteins]] that anchor other subunits of the complex, which form the catalytic core, to the [[inner mitochondrial membrane]]. There are several related [[pseudogenes]] for this gene on different chromosomes. Mutations in this gene have been associated with [[pheochromocytoma]]s and [[paragangliomas]]. Alternatively spliced transcript variants have been described.<ref name="entrez">{{cite web | title = Entrez Gene: succinate dehydrogenase complex| url = https://www.ncbi.nlm.nih.gov/sites/entrez?Db=gene&Cmd=ShowDetailView&TermToSearch=6391}}</ref>

== Structure ==
The gene that codes for the SDHC protein is nuclear, even though the protein is located in the inner membrane of the [[mitochondria]]. The location of the gene in humans is on the [[Chromosome 1 (human)|first chromosome]] at q21. The [[gene]] is  partitioned in six [[exon]]s. The SDHC gene produces an 18.6&nbsp;kDa protein composed of 169 amino acids.<ref name=COPaKB>{{cite journal | vauthors = 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 | title = Integration of cardiac proteome biology and medicine by a specialized knowledgebase | journal = Circulation Research | volume = 113 | issue = 9 | pages = 1043–53 | date = October 2013 | pmid = 23965338 | pmc = 4076475 | doi = 10.1161/CIRCRESAHA.113.301151 }}</ref><ref name="url_COPaKB">{{cite web | url = https://amino.heartproteome.org/web/protein/Q99643 | work = Cardiac Organellar Protein Atlas Knowledgebase (COPaKB) | title = SDHC - Succinate dehydrogenase cytochrome b560 subunit, mitochondrial | access-date = 18 July 2018 | archive-date = 19 July 2018 | archive-url = https://web.archive.org/web/20180719161715/https://amino.heartproteome.org/web/protein/Q99643 | url-status = dead }}</ref>

The SDHC protein is one of the two transmembrane subunits of the four-subunit [[succinate dehydrogenase]] (Complex II) protein complex that resides in the inner [[mitochondrial]] membrane. The other transmembrane subunit is [[SDHD]]. The SDHC/SDHD dimer is connected to the [[SDHB]] electron transport subunit which, in turn, is connected to the [[SDHA]] subunit.<ref>{{cite journal | vauthors = Sun F, Huo X, Zhai Y, Wang A, Xu J, Su D, Bartlam M, Rao Z | title = Crystal structure of mitochondrial respiratory membrane protein complex II | journal = Cell | volume = 121 | issue = 7 | pages = 1043–57 | date = July 2005 | pmid = 15989954 | doi = 10.1016/j.cell.2005.05.025 | s2cid = 16697879 | doi-access = free }}</ref>

== Function ==
[[File:SuccDeh.svg|thumb|left]]
The SDHC protein is one of four nuclear-encoded subunits that comprise [[succinate dehydrogenase]], also known as Complex II of the [[electron transport chain]], a key enzyme complex of the [[citric acid cycle]] and aerobic respiratory chains of mitochondria. The encoded protein is one of two integral membrane proteins that anchor other subunits of the complex, which form the catalytic core, to the inner mitochondrial membrane.<ref name="entrez"/>

SDHC forms part of the transmembrane [[protein dimer]] with [[SDHD]] that anchors [[Complex II]] to the inner mitochondrial membrane. The SDHC/SDHD dimer provides binding sites for [[ubiquinone]] and water during electron transport at [[Complex II]]. Initially, [[SDHA]] oxidizes [[succinate]] via [[deprotonation]] at the [[flavin adenine dinucleotide|FAD]] binding site, forming [[FADH2|FADH<sub>2</sub>]] and leaving [[fumarate]], loosely bound to the active site, free to exit the protein. The electrons derived from succinate tunnel along the [Fe-S] relay in the [[SDHB]] subunit until they reach the [3Fe-4S] [[iron sulfur cluster]]. The electrons are then transferred to an awaiting [[ubiquinone]] molecule at the Q pool active site in the SDHC/SDHD dimer. The O1 [[carbonyl]] oxygen of ubiquinone is oriented at the active site (image 4) by [[hydrogen bond]] interactions with Tyr83 of SDHD. The presence of electrons in the [3Fe-4S] iron sulphur cluster induces the movement of ubiquinone into a second orientation. This facilitates a second hydrogen bond interaction between the O4 carbonyl group of ubiquinone and Ser27 of SDHC. Following the first single electron reduction step, a [[semiquinone]] radical species is formed. The second electron arrives from the [3Fe-4S] cluster to provide full reduction of the ubiquinone to [[ubiquinol]].<ref>{{cite journal | vauthors = Horsefield R, Yankovskaya V, Sexton G, Whittingham W, Shiomi K, Omura S, Byrne B, Cecchini G, Iwata S | title = Structural and computational analysis of the quinone-binding site of complex II (succinate-ubiquinone oxidoreductase): a mechanism of electron transfer and proton conduction during ubiquinone reduction | journal = The Journal of Biological Chemistry | volume = 281 | issue = 11 | pages = 7309–16 | date = March 2006 | pmid = 16407191 | doi = 10.1074/jbc.m508173200 | doi-access = free }}</ref>

== Clinical significance ==
Mutations in this gene have been associated with [[paraganglioma]]s.<ref name="entrez"/><ref name="pmid12658451">{{cite journal | vauthors = Niemann S, Müller U, Engelhardt D, Lohse P | title = Autosomal dominant malignant and catecholamine-producing paraganglioma caused by a splice donor site mutation in SDHC | journal = Human Genetics | volume = 113 | issue = 1 | pages = 92–4 | date = July 2003 | pmid = 12658451 | doi = 10.1007/s00439-003-0938-0 | s2cid = 32412131 }}</ref> More than 30 mutations in the SDHC gene have been found to increase the risk of hereditary paraganglioma-pheochromocytoma type 3. People with this condition have paragangliomas, [[pheochromocytomas]], or both. An inherited SDHC gene mutation predisposes an individual to the condition, and a [[somatic mutation]] that deletes the normal copy of the SDHC gene is needed to cause hereditary paraganglioma-pheochromocytoma type 3. Most of the inherited SDHC gene mutations change single amino acids in the SDHC protein sequence or result in a shortened protein. As a result, there is little or no SDH enzyme activity. Because the mutated SDH enzyme cannot convert [[succinate]] to [[fumarate]], succinate accumulates in the cell. The excess succinate abnormally stabilizes [[hypoxia-inducible factors]] (HIF), which also builds up in cells. Excess HIF stimulates cells to divide and triggers the production of blood vessels when they are not needed. Rapid and uncontrolled cell division, along with the formation of new blood vessels, can lead to the development of tumors in people with hereditary paraganglioma-pheochromocytoma.<ref>{{cite web|title=SDHC|url=http://ghr.nlm.nih.gov/gene/SDHC|website=Genetics Home Reference|publisher=U.S. National Library of Medicine|access-date=26 March 2015}}</ref>

== Interactive pathway map ==
{{TCACycle_WP78|highlight=Succinate_dehydrogenase_complex_subunit_C}}

== References ==
{{Reflist}}

== Further reading ==
{{refbegin | 2}}
* {{cite journal | vauthors = Bayley JP, Weiss MM, Grimbergen A, van Brussel BT, Hes FJ, Jansen JC, Verhoef S, Devilee P, Corssmit EP, Vriends AH | title = Molecular characterization of novel germline deletions affecting SDHD and SDHC in pheochromocytoma and paraganglioma patients | journal = Endocrine-Related Cancer | volume = 16 | issue = 3 | pages = 929–37 | date = September 2009 | pmid = 19546167 | doi = 10.1677/ERC-09-0084 | doi-access = free }}
* {{cite journal | vauthors = Pasini B, McWhinney SR, Bei T, Matyakhina L, Stergiopoulos S, Muchow M, Boikos SA, Ferrando B, Pacak K, Assie G, Baudin E, Chompret A, Ellison JW, Briere JJ, Rustin P, Gimenez-Roqueplo AP, Eng C, Carney JA, Stratakis CA | title = Clinical and molecular genetics of patients with the Carney-Stratakis syndrome and germline mutations of the genes coding for the succinate dehydrogenase subunits SDHB, SDHC, and SDHD | journal = European Journal of Human Genetics | volume = 16 | issue = 1 | pages = 79–88 | date = January 2008 | pmid = 17667967 | doi = 10.1038/sj.ejhg.5201904 | doi-access = free }}
* {{cite journal | vauthors = Gaal J, Burnichon N, Korpershoek E, Roncelin I, Bertherat J, Plouin PF, de Krijger RR, Gimenez-Roqueplo AP, Dinjens WN | title = Isocitrate dehydrogenase mutations are rare in pheochromocytomas and paragangliomas | journal = The Journal of Clinical Endocrinology and Metabolism | volume = 95 | issue = 3 | pages = 1274–8 | date = March 2010 | pmid = 19915015 | doi = 10.1210/jc.2009-2170 | doi-access = free }}
* {{cite journal | vauthors = Milosevic D, Lundquist P, Cradic K, Vidal-Folch N, Huynh T, Pacak K, Grebe SK | title = Development and validation of a comprehensive mutation and deletion detection assay for SDHB, SDHC, and SDHD | journal = Clinical Biochemistry | volume = 43 | issue = 7–8 | pages = 700–4 | date = May 2010 | pmid = 20153743 | pmc = 3419008 | doi = 10.1016/j.clinbiochem.2010.01.016 }}
* {{cite journal | vauthors = Bonache S, Martínez J, Fernández M, Bassas L, Larriba S | title = Single nucleotide polymorphisms in succinate dehydrogenase subunits and citrate synthase genes: association results for impaired spermatogenesis | journal = International Journal of Andrology | volume = 30 | issue = 3 | pages = 144–52 | date = June 2007 | pmid = 17298551 | doi = 10.1111/j.1365-2605.2006.00730.x | doi-access = free }}
* {{cite journal | vauthors = Cascón A, López-Jiménez E, Landa I, Leskelä S, Leandro-García LJ, Maliszewska A, Letón R, de la Vega L, García-Barcina MJ, Sanabria C, Alvarez-Escolá C, Rodríguez-Antona C, Robledo M | title = Rationalization of genetic testing in patients with apparently sporadic pheochromocytoma/paraganglioma | journal = Hormone and Metabolic Research | volume = 41 | issue = 9 | pages = 672–5 | date = September 2009 | pmid = 19343621 | doi = 10.1055/s-0029-1202814 | s2cid = 24979281 }}
* {{cite journal | vauthors = Goto Y, Ando T, Naito M, Goto H, Hamajima N | title = No association of an SDHC gene polymorphism with gastric cancer | journal = Asian Pacific Journal of Cancer Prevention | volume = 7 | issue = 4 | pages = 525–8 | year = 2006 | pmid = 17250422 }}
* {{cite journal | vauthors = Cascón A, Pita G, Burnichon N, Landa I, López-Jiménez E, Montero-Conde C, Leskelä S, Leandro-García LJ, Letón R, Rodríguez-Antona C, Díaz JA, López-Vidriero E, González-Neira A, Velasco A, Matias-Guiu X, Gimenez-Roqueplo AP, Robledo M | title = Genetics of pheochromocytoma and paraganglioma in Spanish patients | journal = The Journal of Clinical Endocrinology and Metabolism | volume = 94 | issue = 5 | pages = 1701–5 | date = May 2009 | pmid = 19258401 | doi = 10.1210/jc.2008-2756 | doi-access = free }}
* {{cite journal | vauthors = Boedeker CC, Neumann HP, Maier W, Bausch B, Schipper J, Ridder GJ | title = Malignant head and neck paragangliomas in SDHB mutation carriers | journal = Otolaryngology–Head and Neck Surgery | volume = 137 | issue = 1 | pages = 126–9 | date = July 2007 | pmid = 17599579 | doi = 10.1016/j.otohns.2007.01.015 | s2cid = 13650583 }}
* {{cite journal | vauthors = Gill AJ, Benn DE, Chou A, Clarkson A, Muljono A, Meyer-Rochow GY, Richardson AL, Sidhu SB, Robinson BG, Clifton-Bligh RJ | title = Immunohistochemistry for SDHB triages genetic testing of SDHB, SDHC, and SDHD in paraganglioma-pheochromocytoma syndromes | journal = Human Pathology | volume = 41 | issue = 6 | pages = 805–14 | date = June 2010 | pmid = 20236688 | doi = 10.1016/j.humpath.2009.12.005 }}
* {{cite journal | vauthors = Ricketts C, Woodward ER, Killick P, Morris MR, Astuti D, Latif F, Maher ER | title = Germline SDHB mutations and familial renal cell carcinoma | journal = Journal of the National Cancer Institute | volume = 100 | issue = 17 | pages = 1260–2 | date = September 2008 | pmid = 18728283 | doi = 10.1093/jnci/djn254 | doi-access = free }}
* {{cite journal | vauthors = McWhinney SR, Pasini B, Stratakis CA | title = Familial gastrointestinal stromal tumors and germ-line mutations | journal = The New England Journal of Medicine | volume = 357 | issue = 10 | pages = 1054–6 | date = September 2007 | pmid = 17804857 | doi = 10.1056/NEJMc071191 | s2cid = 35007543 | doi-access = free }}
* {{cite journal | vauthors = Eng C, Kiuru M, Fernandez MJ, Aaltonen LA | title = A role for mitochondrial enzymes in inherited neoplasia and beyond | journal = Nature Reviews. Cancer | volume = 3 | issue = 3 | pages = 193–202 | date = March 2003 | pmid = 12612654 | doi = 10.1038/nrc1013 | s2cid = 20549458 }}
* {{cite journal | vauthors = Hermsen MA, Sevilla MA, Llorente JL, Weiss MM, Grimbergen A, Allonca E, Garcia-Inclán C, Balbín M, Suárez C | title = Relevance of germline mutation screening in both familial and sporadic head and neck paraganglioma for early diagnosis and clinical management | journal = Cellular Oncology | volume = 32 | issue = 4 | pages = 275–83 | date = January 2010 | pmid = 20208144 | pmc = 4619289 | doi = 10.3233/CLO-2009-0498 }}
* {{cite journal | vauthors = Brière JJ, Favier J, El Ghouzzi V, Djouadi F, Bénit P, Gimenez AP, Rustin P | title = Succinate dehydrogenase deficiency in human | journal = Cellular and Molecular Life Sciences | volume = 62 | issue = 19–20 | pages = 2317–24 | date = October 2005 | pmid = 16143825 | doi = 10.1007/s00018-005-5237-6 | s2cid = 23793565 | pmc = 11139140 }}
* {{cite journal | vauthors = Mannelli M, Castellano M, Schiavi F, Filetti S, Giacchè M, Mori L, Pignataro V, Bernini G, Giachè V, Bacca A, Biondi B, Corona G, Di Trapani G, Grossrubatscher E, Reimondo G, Arnaldi G, Giacchetti G, Veglio F, Loli P, Colao A, Ambrosio MR, Terzolo M, Letizia C, Ercolino T, Opocher G | title = Clinically guided genetic screening in a large cohort of italian patients with pheochromocytomas and/or functional or nonfunctional paragangliomas | journal = The Journal of Clinical Endocrinology and Metabolism | volume = 94 | issue = 5 | pages = 1541–7 | date = May 2009 | pmid = 19223516 | doi = 10.1210/jc.2008-2419 | url = https://iris.unito.it/bitstream/2318/96662/4/Clinically%20Guided%20Genetic%20Screening.pdf | doi-access = free }}
* {{cite journal | vauthors = Richalet JP, Gimenez-Roqueplo AP, Peyrard S, Vénisse A, Marelle L, Burnichon N, Bouzamondo A, Jeunemaitre X, Azizi M, Elghozi JL | title = A role for succinate dehydrogenase genes in low chemoresponsiveness to hypoxia? | journal = Clinical Autonomic Research | volume = 19 | issue = 6 | pages = 335–42 | date = December 2009 | pmid = 19768395 | doi = 10.1007/s10286-009-0028-z | s2cid = 2265162 }}
* {{cite journal | vauthors = Pigny P, Cardot-Bauters C, Do Cao C, Vantyghem MC, Carnaille B, Pattou F, Caron P, Wemeau JL, Porchet N | title = Should genetic testing be performed in each patient with sporadic pheochromocytoma at presentation? | journal = European Journal of Endocrinology | volume = 160 | issue = 2 | pages = 227–31 | date = February 2009 | pmid = 19029228 | doi = 10.1530/EJE-08-0574 | s2cid = 31746044 | doi-access =  }}
* {{cite journal | vauthors = Korpershoek E, Van Nederveen FH, Dannenberg H, Petri BJ, Komminoth P, Perren A, Lenders JW, Verhofstad AA, De Herder WW, De Krijger RR, Dinjens WN | title = Genetic analyses of apparently sporadic pheochromocytomas: the Rotterdam experience | journal = Annals of the New York Academy of Sciences | volume = 1073 | pages = 138–48 | date = August 2006 | issue = 1 | pmid = 17102080 | doi = 10.1196/annals.1353.014 | bibcode = 2006NYASA1073..138K | s2cid = 8418586 }}
* {{cite journal | vauthors = Wang L, McDonnell SK, Hebbring SJ, Cunningham JM, St Sauver J, Cerhan JR, Isaya G, Schaid DJ, Thibodeau SN | title = Polymorphisms in mitochondrial genes and prostate cancer risk | journal = Cancer Epidemiology, Biomarkers & Prevention | volume = 17 | issue = 12 | pages = 3558–66 | date = December 2008 | pmid = 19064571 | pmc = 2750891 | doi = 10.1158/1055-9965.EPI-08-0434 }}
{{refend}}

== External links ==
* [https://www.ncbi.nlm.nih.gov/books/NBK1548/  GeneReviews/NCBI/NIH/UW entry on Hereditary Paraganglioma-Pheochromocytoma Syndromes]

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