Sensitivity of the aldehyde-induced and free fatty acid-induced activities of plant uncoupling protein to GTP is regulated by the ubiquinone reduction level.
Using isolated potato tuber mitochondria possessing uncoupling protein (StUCP), we found that, under non-phosphorylating conditions, the sensitivity of aldehyde (all trans-retinal or 4-hydroxy-2-nonenal)-induced and fatty acid (linoleic acid)-induced StUCP-mediated proton leaks to GTP is controlled by the endogenous ubiquinone (Q) reduction level. The action of StUCP activators was abolished by GTP only when Q was sufficiently oxidized, but no inhibitory effect was observed when Q was highly reduced. Thus, the Q reduction level-dependent regulation of StUCP inhibition functions independently of the type of UCP activation and could be an important physiological factor affecting the efficiency of UCP-catalyzed uncoupling in plant mitochondria.
Laboratory of Bioenergetics, Adam Mickiewicz University, Umultowska 89, 61-614 Poznan, Poland.
Andrzej M
AM
Woyda-Ploszczyca
Laboratory of Bioenergetics, Adam Mickiewicz University, Umultowska 89, 61-614 Poznan, Poland. Electronic address: wiesiaj@amu.edu.pl.
Wieslawa
W
Jarmuszkiewicz
D000447:Aldehydes / Q000494:pharmacology*; D019787:Linoleic Acid / Q000494:pharmacology*; D010940:Plant Proteins / Q000378:metabolism*; D011685:Purine Nucleotides / Q000378:metabolism; D011198:Solanum tuberosum / Q000187:drug effects / Q000378:metabolism; D014451:Ubiquinone / Q000494:pharmacology*
D000447:Aldehydes; D010940:Plant Proteins; D011685:Purine Nucleotides; D014451:Ubiquinone; D019787:Linoleic Acid
Aldehydes (all trans-retinal and 4-hydroxy-2-nonenal); Linoleic acid; Purine nucleotides; Solanum tuberosum; Ubiquinone reduction level; Uncoupling protein