UQCC2

Ubiquinol-cytochrome c reductase complex assembly factor 2 is a protein that in humans is encoded by the UQCC2 gene. Located in the mitochondrial nucleoid, this protein is a complex III assembly factor, playing a role in cytochrome b biogenesis along with the UQCC1 protein.^[5] It regulates insulin secretion and mitochondrial ATP production and oxygen consumption.^[6][7] In the sole recorded case, a mutation in the UQCC2 gene caused Complex III deficiency, characterized by intrauterine growth retardation, neonatal lactic acidosis, and renal tubular dysfunction.^[8]

UQCC2
Identifiers
Aliases	UQCC2, C6orf125, Cbp6, M19, MNF1, bA6B20.2, ubiquinol-cytochrome c reductase complex assembly factor 2, C6orf126, MC3DN7
External IDs	OMIM: 614461; MGI: 1914517; HomoloGene: 12105; GeneCards: UQCC2; OMA:UQCC2 - orthologs
Gene location (Human) Chr. Chromosome 6 (human)[1] Band 6p21.31 Start 33,694,293 bp[1] End 33,711,727 bp[1]
Gene location (Mouse) Chr. Chromosome 17 (mouse)[2] Band 17|17 A3.3 Start 27,341,637 bp[2] End 27,352,890 bp[2]
RNA expression pattern Bgee Human Mouse (ortholog) Top expressed in apex of heart right auricle of heart left ventricle right testis left testis myocardium of left ventricle gastrocnemius muscle muscle of thigh anterior pituitary islet of Langerhans Top expressed in spermatid spermatocyte muscle of thigh lip dentate gyrus of hippocampal formation granule cell superior frontal gyrus yolk sac interventricular septum primary visual cortex ventricular zone More reference expression data BioGPS n/a
Gene ontology Molecular function protein binding Cellular component mitochondrial inner membrane mitochondrial matrix mitochondrial intermembrane space mitochondrial nucleoid membrane mitochondrion nuclear body Biological process regulation of oxidative phosphorylation regulation of skeletal muscle cell differentiation regulation of insulin secretion positive regulation of mitochondrial translation mitochondrial respiratory chain complex III assembly Sources:Amigo / QuickGO
Orthologs Species Human Mouse Entrez 84300 67267 Ensembl ENSG00000137288 ENSMUSG00000024208 UniProt Q9BRT2 Q9CQY6 RefSeq (mRNA) NM_032340 NM_026063 NM_001364944 RefSeq (protein) NP_115716 NP_080339 NP_001351873 Location (UCSC) Chr 6: 33.69 – 33.71 Mb Chr 17: 27.34 – 27.35 Mb PubMed search [3] [4]
Wikidata
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Structure

The UQCC2 gene is located on the p arm of chromosome 6 in position 21.31 and spans 14,990 base pairs.^[5] The gene produces a 14.9 kDa protein composed of 126 amino acids.^[9][10] This protein has no homologous domains with other known proteins. It is associated with the mitochondrial nucleoid, likely located in the peripheral region.^[7] This protein's distribution pattern is similar to other components of the mitochondrial nucleoid, like mtSSB and PHB1/PHB2.^[11]

Function

This gene encodes a nucleoid protein localized to the mitochondrial inner membrane and sublocalized to the mitochondrial matrix.^[11] The encoded protein permissively regulates insulin secretion in pancreatic beta cells, positively regulates mitochondrial ATP production and oxygen consumption, and is involved in late skeletal muscle differentiation through modulation of mitochondrial respiratory chain activity.^[7] This protein is required for the assembly of the Complex III. Expression of this protein is decreased in cells with low mtDNA.^[11]

Clinical Significance

In the sole recorded case, a homozygous mutation in intron 2 of the UQCC2 gene caused a splicing disruption; the patient presented with symptoms of nuclear type 7 Complex III deficiency, including neonatal lactic acidosis, renal tubulopathy, and severe intrauterine growth retardation. Additional clinical features included a dysmorphic facial appearance, delayed psychomotor development, autistic features, aggressive behavior, and mild sensorineural hearing loss.^[6] Additionally, the patient had decreased levels of UQCC1.^[8]

Interactions

This protein interacts with UQCC1.^[6]