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Mitochondrial uncoupling protein 2 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 ''UCP2'' 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 ...
.
Mitochondrial uncoupling proteins (UCP) are members of the larger family of mitochondrial anion carrier proteins (MACP). UCPs separate, or uncouple, oxidative phosphorylation
Oxidative phosphorylation (UK , US ) or electron transport-linked phosphorylation or terminal oxidation is the metabolic pathway in which cells use enzymes to oxidize nutrients, thereby releasing chemical energy in order to produce adenosine tri ...
from ATP synthesis
ATP synthase is a protein that catalyzes the formation of the energy storage molecule adenosine triphosphate (ATP) using adenosine diphosphate (ADP) and inorganic phosphate (Pi). It is classified under ligases as it changes ADP by the formation o ...
by dissipating the mitochondrial membrane potential as heat, also referred to as the mitochondrial proton leak. UCPs facilitate the transfer of anions from the inner to the outer mitochondrial membrane and the return transfer of protons from the outer to the inner mitochondrial membrane. They also reduce the mitochondrial membrane potential in mammalian cells, which reduces production of reactive oxygen species
In chemistry, reactive oxygen species (ROS) are highly reactive chemicals formed from diatomic oxygen (). Examples of ROS include peroxides, superoxide, hydroxyl radical, singlet oxygen, and alpha-oxygen.
The reduction of molecular oxygen () p ...
(ROS).
In contrast to UCP1 and UCP3, which are primarily expressed in adipose and smooth muscle, UCP2 is expressed on many different tissues including the kidney, liver, GI tract, brain, and skeletal muscle.
The exact mechanisms of anion transfer by UCPs are not known. UCPs contain the three homologous protein domains of MACPs. Although it was originally thought to play a role in non-shivering thermogenesis, obesity, diabetes and atherosclerosis, it now appears that the main function of UCP2 is the control of mitochondria-derived reactive oxygen species.
Chromosomal order is 5'-UCP3-UCP2-3'.
See also
*Uncoupling protein
An uncoupling protein (UCP) is a mitochondrial inner membrane protein that is a regulated proton channel or transporter. An uncoupling protein is thus capable of dissipating the proton gradient generated by NADH-powered pumping of protons from th ...
References
Further reading
* * * * * * * * * * * * * * * * * * * * Solute carrier family {{membrane-protein-stub