Ubiquinol-cytochrome c reductase, complex III subunit VII, 9.5kDa is a

protein Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residues. Proteins perform a vast array of functions within organisms, including catalysing metabolic reactions, DNA replication, respo ...

that in humans is encoded by the ''UQCRQ''

gene In biology, the word gene (from , ; "...Wilhelm Johannsen coined the word gene to describe the Mendelian units of heredity..." meaning ''generation'' or ''birth'' or ''gender'') can have several different meanings. The Mendelian gene is a ba ...

. This ubiqinone-binding protein is a

subunit Subunit may refer to: *Subunit HIV vaccine, a class of HIV vaccine *Protein subunit, a protein molecule that assembles with other protein molecules *Monomer, a molecule that may bind chemically to other molecules to form a polymer *Sub-subunit, a ...

mitochondrial A mitochondrion (; ) is an organelle found in the cells of most Eukaryotes, such as animals, plants and fungi. Mitochondria have a double membrane structure and use aerobic respiration to generate adenosine triphosphate (ATP), which is use ...

Complex III Complex commonly refers to: * Complexity, the behaviour of a system whose components interact in multiple ways so possible interactions are difficult to describe ** Complex system, a system composed of many components which may interact with each ...

in the

electron transport chain An electron transport chain (ETC) is a series of protein complexes and other molecules that transfer electrons from electron donors to electron acceptors via redox reactions (both reduction and oxidation occurring simultaneously) and couples th ...

. A

mutation In biology, a mutation is an alteration in the nucleic acid sequence of the genome of an organism, virus, or extrachromosomal DNA. Viral genomes contain either DNA or RNA. Mutations result from errors during DNA or viral replication, mi ...

in the ''UQCRQ'' gene has been shown to cause severe

neurological disorder A neurological disorder is any disorder of the nervous system. Structural, biochemical or electrical abnormalities in the brain, spinal cord or other nerves can result in a range of symptoms. Examples of symptoms include paralysis, muscle weakn ...

Infection An infection is the invasion of tissues by pathogens, their multiplication, and the reaction of host tissues to the infectious agent and the toxins they produce. An infectious disease, also known as a transmissible disease or communicable dise ...

by ''

Trypanosoma cruzi ''Trypanosoma cruzi'' is a species of parasitic euglenoids. Among the protozoa, the trypanosomes characteristically bore tissue in another organism and feed on blood (primarily) and also lymph. This behaviour causes disease or the likelihood of ...

'' can cause oxidative modification of this protein in

cardiac muscle Cardiac muscle (also called heart muscle, myocardium, cardiomyocytes and cardiac myocytes) is one of three types of vertebrate muscle tissues, with the other two being skeletal muscle and smooth muscle. It is an involuntary, striated muscle th ...

tissue.

Structure

The ''UQCRQ'' gene is located on the q arm of

chromosome 5 Chromosome 5 is one of the 23 pairs of chromosomes in humans. People normally have two copies of this chromosome. Chromosome 5 spans about 181 million base pairs (the building blocks of DNA) and represents almost 6% of the total DNA in cells. Ch ...

in position 31.1 and spans 2,217 base pairs. The gene produces a 9.9 kDa protein composed of 82

amino acids Amino acids are organic compounds that contain both amino and carboxylic acid functional groups. Although hundreds of amino acids exist in nature, by far the most important are the alpha-amino acids, which comprise proteins. Only 22 alpha am ...

. This protein is transmembranous, with more mass on the

matrix Matrix most commonly refers to: * ''The Matrix'' (franchise), an American media franchise ** ''The Matrix'', a 1999 science-fiction action film ** "The Matrix", a fictional setting, a virtual reality environment, within ''The Matrix'' (franchis ...

side of the

membrane A membrane is a selective barrier; it allows some things to pass through but stops others. Such things may be molecules, ions, or other small particles. Membranes can be generally classified into synthetic membranes and biological membranes. B ...

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 An electron transport chain (ETC) is a series of protein complexes and other molecules that transfer electrons from electron donors to electron acceptors via redox reactions (both reduction and oxidation occurring simultaneously) and couples thi ...

Clinical significance

Variants of UQCRQ have been associated with complex III deficiency. One set of twenty

consanguineous Consanguinity ("blood relation", from Latin '' consanguinitas'') is the characteristic of having a kinship with another person (being descended from a common ancestor). Many jurisdictions have laws prohibiting people who are related by blood fro ...

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 Inbreeding is the production of offspring from the mating or breeding of individuals or organisms that are closely related genetically. By analogy, the term is used in human reproduction, but more commonly refers to the genetic disorders and o ...

Israeli

Bedouin The Bedouin, Beduin, or Bedu (; , singular ) are nomadic Arab tribes who have historically inhabited the desert regions in the Arabian Peninsula, North Africa, the Levant, and Mesopotamia. The Bedouin originated in the Syrian Desert and A ...

family, the mutations, inherited in an

autosomal recessive In genetics, dominance is the phenomenon of one variant (allele) of a gene on a chromosome masking or overriding the effect of a different variant of the same gene on the other copy of the chromosome. The first variant is termed dominant and t ...

pattern, displayed the

phenotype In genetics, the phenotype () is the set of observable characteristics or traits of an organism. The term covers the organism's morphology or physical form and structure, its developmental processes, its biochemical and physiological proper ...

of mitochondrial Complex III deficiency, nuclear type 4, accompanied by severe

neurological symptoms A neurological disorder is any disorder of the nervous system. Structural, biochemical or electrical abnormalities in the brain, spinal cord or other nerves can result in a range of symptoms. Examples of symptoms include paralysis, muscle weakness ...

. Other symptoms of complex III deficiency linked to these mutations have included

hypoglycemia Hypoglycemia, also called low blood sugar, is a fall in blood sugar to levels below normal, typically below 70 mg/dL (3.9 mmol/L). Whipple's triad is used to properly identify hypoglycemic episodes. It is defined as blood glucose belo ...

lactic acidosis Lactic acidosis is a medical condition characterized by a build-up of lactate (especially -lactate) in the body, with formation of an excessively low pH in the bloodstream. It is a form of metabolic acidosis, in which excessive acid accumulates ...

, and

hypotonia Hypotonia is a state of low muscle tone (the amount of tension or resistance to stretch in a muscle), often involving reduced muscle strength. Hypotonia is not a specific medical disorder, but a potential manifestation of many different diseases a ...

. 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 Cytochrome b-c1 complex subunit 1, mitochondrial is a protein that in humans is encoded by the ''UQCRC1'' gene. Its gene product is a subunit of the respiratory chain protein Ubiquinol Cytochrome c Reductase (UQCR, Complex III or Cytochrome bc1 c ...

and

UQCRC2 Cytochrome b-c1 complex subunit 2, mitochondrial (UQCRC2), also known as QCR2, UQCR2, or MC3DN5 is a protein that in humans is encoded by the ''UQCRC2'' gene. The product of ''UQCRC2'' is a subunit of the respiratory chain protein Ubiquinol Cyto ...

of the same core complex and

UQCRH Cytochrome b-c1 complex subunit 6, mitochondrial is a protein that in humans is encoded by the ''UQCRH'' gene. Its gene product is a subunit of the respiratory chain protein Ubiquinol Cytochrome c Reductase (UQCR, Complex III or Cytochrome bc1 c ...

and

CYC1 Cytochrome c1, heme protein, mitochondrial (CYC1), also known as UQCR4, MC3DN6, Complex III subunit 4, Cytochrome b-c1 complex subunit 4, or Ubiquinol-cytochrome-c reductase complex cytochrome c1 subunit is a protein that in humans is encoded by t ...

of the neighboring subcomplex.

Interactions

The protein encoded by ''UQCRQ'' has protein-protein interactions with

, OPTN,

ERCC8 DNA excision repair protein ERCC-8 is a protein that in humans is encoded by the ''ERCC8'' gene. This gene encodes a WD repeat protein, which interacts with the Cockayne syndrome type B (CSB) and p44 proteins, the latter being a subunit of the R ...

GRINL1A GRINL1A complex locus protein 1 is a protein that in humans is encoded by the ''GRINL1A'' gene. This gene (GRINL1A) is part of a complex transcript unit that includes the gene for GRINL1A combined protein (Gcom1). Transcription of this gene occurs ...

Dctn1 Dynactin subunit 1 is a protein that in humans is encoded by the ''DCTN1'' gene. Function This gene encodes the largest subunit of dynactin, a macromolecular complex consisting of 23 subunits (11 individual proteins ranging in size from 22 to ...

, K8.1,

XRCC3 DNA repair protein XRCC3 is a protein that in humans is encoded by the ''XRCC3'' gene. Function This gene encodes a member of the RecA/Rad51-related protein family that participates in homologous recombination to maintain chromosome stability a ...

, PML,

RAB7A Ras-related protein Rab-7a is a protein that in humans is encoded by the ''RAB7A'' gene. Ras-related protein Rab-7a is involved in endocytosis, which is a process that brings substances into a cell. The process of endocytosis works by folding the ...

, HNRNPA1L2,

CDC73 Cell division cycle 73, Paf1/RNA polymerase II complex component, homolog (S. cerevisiae), also known as CDC73 and parafibromin, is a protein which in humans is encoded by the CDC73 gene. Function Parafibromin, LEO1, PAF1, and CTR9 form the P ...

NLRP3 NLR family pyrin domain containing 3 (NLRP3) (previously known as NACHT, LRR and PYD domains-containing protein 3 ALP3and cryopyrin), is a protein that in humans is encoded by the ''NLRP3'' gene located on the long arm of chromosome 1. NLRP3 is ...

HAUS2 Haus is a Germanic word meaning ''house''. It may refer to: People * Anton Haus (1851–1917), Austrian grand admiral, fleet commander of the Austro-Hungarian Navy in World War I * Georg Haus (1895–1945), German general * Hermann A. H ...

TMEM248 Transmembrane protein 248, also known as C7orf42, is a gene that in humans encodes the TMEM248 protein. This gene contains multiple transmembrane domains and is composed of seven exons.TMEM248 is predicted to be a component of the plasma membrane ...

, and

GOLT1B Vesicle transport protein GOT1B is a protein that in humans is encoded by the ''GOLT1B'' gene. Got1p is a protein that aides in vesicle transport through the Golgi apparatus of the cell. Got1p has a calculated mass of 15.4 kDa and consists of 138 ...

Structure

Function

Clinical significance

Interactions

References

Further reading