New insights into mechanisms of anion uniport through the uncoupling protein of brown adipose tissue mitochondria
Garlid, K.D.
Biochimica et Biophysica Acta 1018(2-3): 151-154
1990
ISSN/ISBN: 0006-3002 PMID: 1697480 DOI: 10.1016/0005-2728(90)90237-x
Accession: 032531002
GDP-sensitive Cl- uniport is a widely studied property of the uncoupling protein of brown adipose tissue mitochondria; nevertheless, little is known about its mechanism and there is even controversy over whether this protein transports Cl-. Using a fluorescent probe assay, we have demonstrated non-ohmic, electrophoretic, GDP-sensitive Cl- uniport into proteoliposomes reconstituted with purified uncoupler protein. We have also identified a large number of new anionic substrates for this porter that also inhibit Cl- uniport competitively. Anion transport, its inhibition by GDP and anion inhibition of Cl- uniport are all strongly dependent on anion hydrophobicity. These surprising results are consequential for hypotheses of common transport mechanisms in the gene family of mitochondrial anion porters.