Uncoupling proteins--a new family of proteins with unknown function

Nutr Neurosci. 2002 Feb;5(1):1-11. doi: 10.1080/10284150290007038.


Uncoupling proteins are inner mitochondrial membrane proteins, which dissipate the proton gradient, releasing the stored energy as heat. Five proteins have been cloned, named UCP1, UCP2, UCP3, UCP4 and UCP5/BMCP1. These proteins are structurally related but differ in tissue expression. UCP1 is expressed uniquely in the brown adipose tissue, while UCP2 is widely distributed, UCP3 is mainly restricted to skeletal muscle and UCP4 and UCP5/BMCP1 expressed in the brain. The properties and regulation of the uncoupling proteins and their exact function has been the focus of an intense research during recent years. This review briefly summarizes the actual knowledge of the properties and function of this new family of proteins. While UCP1 has a clear role in energy homeostasis, the newcomers UCP2-UCP5 may have more delicate physiological importance acting as free radical oxygen scavengers and in the regulation of ATP-dependent processes, such as secretion.

Publication types

  • Research Support, Non-U.S. Gov't
  • Review

MeSH terms

  • Animals
  • Brain Chemistry
  • Carrier Proteins / physiology*
  • Diabetes Mellitus
  • Energy Metabolism
  • Free Radical Scavengers
  • Humans
  • Ion Channels
  • Membrane Proteins / physiology*
  • Membrane Transport Proteins*
  • Mitochondrial Proteins*
  • Mitochondrial Uncoupling Proteins
  • Muscle, Skeletal / chemistry
  • Nerve Tissue Proteins / physiology
  • Obesity
  • Proteins / physiology
  • Tissue Distribution
  • Uncoupling Agents*
  • Uncoupling Protein 1
  • Uncoupling Protein 2
  • Uncoupling Protein 3


  • Carrier Proteins
  • Free Radical Scavengers
  • Ion Channels
  • Membrane Proteins
  • Membrane Transport Proteins
  • Mitochondrial Proteins
  • Mitochondrial Uncoupling Proteins
  • Nerve Tissue Proteins
  • Proteins
  • SLC25A14 protein, human
  • SLC25A27 protein, human
  • UCP1 protein, human
  • UCP2 protein, human
  • UCP3 protein, human
  • Uncoupling Agents
  • Uncoupling Protein 1
  • Uncoupling Protein 2
  • Uncoupling Protein 3