RT Journal Article
SR Electronic
T1 Mitochondria are physiologically maintained at close to 50 °C
JF bioRxiv
FD Cold Spring Harbor Laboratory
SP 133223
DO 10.1101/133223
A1 Dominique Chrétien
A1 Paule Bénit
A1 Hyung-Ho Ha
A1 Susanne Keipert
A1 Riyad El-Khoury
A1 Young-Tae Chang
A1 Martin Jastroch
A1 Howard T Jacobs
A1 Pierre Rustin
A1 Malgorzata Rak
YR 2017
UL http://biorxiv.org/content/early/2017/05/02/133223.abstract
AB In warm-blooded species, heat released as a by-product of metabolism ensures stable internal temperature throughout the organism, despite varying environmental conditions. Mitochondria are major actors in this thermogenic process. The energy released by the oxidation of respiratory substrates drives ATP synthesis and metabolite transport, with a variable proportion released as heat. Using a temperature-sensitive fluorescent probe targeted to mitochondria, we measured mitochondrial temperature in situ under different physiological conditions. At a constant external temperature of 38 °C, mitochondria were more than 10 °C warmer when the respiratory chain was fully functional, both in HEK cells and primary skin fibroblasts. This differential was abolished by respiratory inhibitors or in cells lacking mitochondrial DNA, but enhanced by expressing thermogenic enzymes such as the alternative oxidase or the uncoupling protein UCP1. The activity of various RC enzymes was maximal at, or slightly above, 50 °C. Our study prompts a re-examination of the literature on mitochondria, taking account of the inferred high temperature.AOXAlternative oxidaseCNEClearnative ElectrophoresisERTYEndoplasmic Reticulum Thermo YellowEtBrEthidium bromideMTGMitoTracker GreenMTYMitoThermo YellowRCRespiratory chainUCP1Uncouplin protein 1