The mechanism of proton transport mediated by mitochondrial uncoupling proteins.
نویسندگان
چکیده
The effort to understand the mechanism of uncoupling by UCP has devolved into two models - the fatty acid protonophore model and the proton buffering model. Evidence for each hypothesis is summarized and evaluated. We also evaluate the obligatory requirement for fatty acids in UCP1-mediated uncoupling and the question of fatty acid affinity for UCP1. The structural bases of UCP transport function and nucleotide inhibition are discussed in light of recent mutagenesis studies and in relationship to the sequences of newly discovered UCPs.
منابع مشابه
Alkylsulfonates as probes of uncoupling protein transport mechanism. Ion pair transport demonstrates that direct H(+) translocation by UCP1 is not necessary for uncoupling.
The mechanism of fatty acid-dependent uncoupling by mitochondrial uncoupling proteins (UCP) is still in debate. We have hypothesized that the anionic fatty acid head group is translocated by UCP, and the proton is transported electroneutrally in the bilayer by flip-flop of the protonated fatty acid. Alkylsulfonates are useful as probes of the UCP transport mechanism. They are analogues of fatty...
متن کاملDecreased Uncoupling Protein 2 and 3 (UCP2 and UCP3) mRNA expression by endurance exercise training with and without chronic administration of nandrolone in rat heart
Introduction: The effect of regular exercise in decreasing the incidence of heart diseases is well known. The abuse of anabolic androgenic steroids (AAS) has been associated with cardiovascular disorders. Uncoupling proteins (UCPs) transport protons across the inner mitochondrial membrane thereby proton gradient can be diminished by the action of UCPs. This process will result in the uncoupl...
متن کاملSuperoxide activates mitochondrial uncoupling protein 2 from the matrix side. Studies using targeted antioxidants.
Superoxide activates nucleotide-sensitive mitochondrial proton transport through the uncoupling proteins UCP1, UCP2, and UCP3 (Echtay, K. S., et al. (2002) Nature 415, 1482-1486). Two possible mechanisms were proposed: direct activation of the UCP proton transport mechanism by superoxide or its products and a cycle of hydroperoxyl radical entry coupled to UCP-catalyzed superoxide anion export. ...
متن کاملHigh membrane potential promotes alkenal-induced mitochondrial uncoupling and influences adenine nucleotide translocase conformation
Mitochondria generate reactive oxygen species, whose downstream lipid peroxidation products, such as 4-hydroxynonenal, induce uncoupling of oxidative phosphorylation by increasing proton leak through mitochondrial inner membrane proteins such as the uncoupling proteins and adenine nucleotide translocase. Using mitochondria from rat liver, which lack uncoupling proteins, in the present study we ...
متن کاملA biophysical study on molecular physiology of the uncoupling proteins of the central nervous system
Mitochondrial inner membrane uncoupling proteins (UCPs) facilitate transmembrane (TM) proton flux and consequently reduce the membrane potential and ATP production. It has been proposed that the three neuronal human UCPs (UCP2, UCP4 and UCP5) in the central nervous system (CNS) play significant roles in reducing cellular oxidative stress. However, the structure and ion transport mechanism of th...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
عنوان ژورنال:
- FEBS letters
دوره 438 1-2 شماره
صفحات -
تاریخ انتشار 1998