page_title: Uncoupling protein
section_title: Functions in neurons
hierarchical_section_title: Uncoupling protein / In mammals / Functions in neurons
caption_attribution_description: English: The function of uncoupling protein UCP1 is shown with respect to the electron transport chain
context_page_description: An uncoupling protein 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 the mitochondrial matrix to the mitochondrial intermembrane space. The energy lost in dissipating the proton gradient via UCPs is not used to do biochemical work. Instead, heat is generated. This is what links UCP to thermogenesis. However, not all kinds of UCPs are related to thermogenesis. Although UCP2 and UCP3 are closely related to UCP1, UCP2 and UCP3 do not affect thermoregulatory abilities of vertebrates. UCPs are positioned in the same membrane as the ATP synthase, which is also a proton channel. The two proteins thus work in parallel with one generating heat and the other generating ATP from ADP and inorganic phosphate, the last step in oxidative phosphorylation. Mitochondria respiration is coupled to ATP synthesis but is regulated by UCPs.
  Uncoupling proteins play a role in normal physiology, as in cold exposure or hibernation, because the energy is used to generate heat instead of producing ATP.
context_section_description: By detecting the associated mRNA, UCP₂, UCP₄, and UCP₅ were shown to reside in neurons throughout the human central nervous system. These proteins play key roles in neuronal function. While many study findings remain controversial, several findings are widely accepted.
  For example, UCP's alter the free calcium concentrations in the neuron. Mitochondria are a major site of calcium storage in neurons, and the storage capacity increases with potential across mitochondrial membranes. Therefore, when the uncoupling proteins reduce potential across these membranes, calcium ions are released to the surrounding environment in the neuron. Due to the high concentrations of mitochondria near axon terminals, this implies UCP's play a role in regulating calcium concentrations in this region. Considering calcium ions play a large role in neurotransmission, scientists predict that these UCP's directly affect neurotransmission.
  
  As discussed above, neurons in the hippocampus experience increased concentrations of ATP in the presence of these uncoupling proteins. This leads scientists to hypothesize that UCP's improve synaptic plasticity and transmission.
caption: This diagram shows the location of UCP1 with respect to the electron transport chain.
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