title: The basal proton conductance of mitochondria depends on adenine nucleotide translocase content.
abstract: The basal proton conductance of mitochondria causes mild uncoupling and may be an important contributor to metabolic rate. The molecular nature of the proton-conductance pathway is unknown. We show that the proton conductance of muscle mitochondria from mice in which isoform 1 of the adenine nucleotide translocase has been ablated is half that of wild-type controls. Overexpression of the adenine nucleotide translocase encoded by the stress-sensitive B gene in Drosophila mitochondria increases proton conductance, and underexpression decreases it, even when the carrier is fully inhibited using carboxyatractylate. We conclude that half to two-thirds of the basal proton conductance of mitochondria is catalysed by the adenine nucleotide carrier, independently of its ATP/ADP exchange or fatty-acid-dependent proton-leak functions.
authors.affiliation: Medical Research Council Dunn Human Nutrition Unit, Hills Road, Cambridge CB2 2XY, UK. martin.brand@mrc-dunn.cam.ac.uk
authors.forename: Martin D
authors.initials: MD
authors.lastname: Brand
authors.forename: Julian L
authors.initials: JL
authors.lastname: Pakay
authors.forename: Augustine
authors.initials: A
authors.lastname: Ocloo
authors.forename: Jason
authors.initials: J
authors.lastname: Kokoszka
authors.forename: Douglas C
authors.initials: DC
authors.lastname: Wallace
authors.forename: Paul S
authors.initials: PS
authors.lastname: Brookes
authors.forename: Emma J
authors.initials: EJ
authors.lastname: Cornwall
mesh_terms: D000818:Animals; D002417:Cattle; D019069:Cell Respiration; D029721:Drosophila Proteins / Q000378:metabolism; D004331:Drosophila melanogaster / Q000201:enzymology / Q000235:genetics; D005260:Female; D015971:Gene Expression Regulation, Enzymologic; D006736:Horses; D008297:Male; D008564:Membrane Potentials; D051379:Mice; D018345:Mice, Knockout; D008928:Mitochondria / Q000201:enzymology / Q000378:metabolism*; D000226:Mitochondrial ADP, ATP Translocases / Q000172:deficiency / Q000235:genetics / Q000378:metabolism*; D010743:Phospholipids / Q000378:metabolism; D011485:Protein Binding; D011522:Protons; D011817:Rabbits; D051381:Rats; D013552:Swine
chemical_list: D029721:Drosophila Proteins; D010743:Phospholipids; D011522:Protons; C491544:sesB protein, Drosophila; D000226:Mitochondrial ADP, ATP Translocases