Certain aspects of uncoupling due to mitochondrial uncoupling proteins in vitro and in vivo

Thermogenic uncoupling has been proven only for UCP1 in brown adipose tissue. All other isoforms of UCPs are potentially acting in suppression of mitochondrial reactive oxygen species (ROS) production. In this contribution we show that BAT mitochondria can be uncoupled by lauric acid in the range of ∼100 nM when endogenous fatty acids are combusted by carnitine cycle and β-oxidation is properly separated from the uncoupling effect. Respiration increased up to 3 times when related to the lowest fatty acid content (BSA present plus carnitine cycle). We also illustrated that any effect leading to more coupled states leads to enhanced H 2 O 2 generation and any effect resulting in uncoupling gives reduced H 2 O 2 generation in BAT mitochondria. Finally, we report doubling of plant UCP transcript in cells as well as amount of protein detected by 3 H-GTP-binding sites in mitochondria of shoots and roots of maize seedlings subjected to the salt stress.