title: Natural and azido fatty acids inhibit phosphate transport and activate fatty acid anion uniport mediated by the mitochondrial phosphate carrier.
abstract: The electroneutral P(i) uptake via the phosphate carrier (PIC) in rat liver and heart mitochondria is inhibited by fatty acids (FAs), by 12-(4-azido-2-nitrophenylamino)dodecanoic acid (AzDA) and heptylbenzoic acid ( approximately 1 microm doses) and by lauric, palmitic, or 12-azidododecanoic acids ( approximately 0.1 mm doses). In turn, reconstituted E. coli-expressed yeast PIC mediated anionic FA uniport with a similar pattern leading to FA cycling and H(+) uniport. The kinetics of P(i)/P(i) exchange on recombinant PIC in the presence of AzDA better corresponded to a competitive inhibition mechanism. Methanephosphonate was identified as a new PIC substrate. Decanephosphonate, butanephosphonate, 4-nitrophenylphosphate, and other P(i) analogs were not translocated and did not inhibit P(i) transport. However, methylenediphosphonate and iminodi(methylenephosphonate) inhibited both electroneutral P(i) uptake and FA cycling via PIC. AzDA analog 16-(4-azido-2-nitrophenylamino)-[(3)H(4)]-hexadecanoic acid ((3)H-AzHA) bound upon photoactivation to several mitochondrial proteins, including the 30- and 34-kDa bands. The latter was ascribed to PIC due to its specific elution pattern on Blue Sepharose and Affi-Gel. (3)H-AzHA photolabeling of recombinant PIC was prevented by methanephosphonate and diphosphonates and after premodification with 4-azido-2-nitrophenylphosphate. Hence, the demonstrated PIC interaction with monovalent long-chain FA anions, but with divalent phosphonates of short chain only, indicates a pattern distinct from that valid for the mitochondrial uncoupling protein-1.
authors.affiliation: Institute of Physiology, Department of Membrane Transport Biophysics, Academy of Sciences of the Czech Republic, Prague CZ 14220, Czech Republic.
authors.forename: H
authors.initials: H
authors.lastname: Engstová
authors.forename: M
authors.initials: M
authors.lastname: Zácková
authors.forename: M
authors.initials: M
authors.lastname: Růzicka
authors.forename: A
authors.initials: A
authors.lastname: Meinhardt
authors.forename: J
authors.initials: J
authors.lastname: Hanus
authors.forename: R
authors.initials: R
authors.lastname: Krämer
authors.forename: P
authors.initials: P
authors.lastname: Jezek
mesh_terms: D000345:Affinity Labels / Q000494:pharmacology; D000818:Animals; D001693:Biological Transport, Active; D002352:Carrier Proteins / Q000037:antagonists & inhibitors* / Q000378:metabolism*; D004164:Diphosphonates / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D005227:Fatty Acids / Q000378:metabolism / Q000494:pharmacology*; D017136:Ion Transport; D007700:Kinetics; D007850:Lauric Acids / Q000494:pharmacology*; D008928:Mitochondria / Q000187:drug effects / Q000378:metabolism; D010169:Palmitic Acids / Q000494:pharmacology; D028044:Phosphate-Binding Proteins; D010710:Phosphates / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar
chemical_list: C098506:12-(4-azido-2-nitrophenylamino)dodecanoic acid; C098967:16-(4-azido-2-nitrophenylamino)hexadecanoic acid; D000345:Affinity Labels; D002352:Carrier Proteins; D004164:Diphosphonates; D005227:Fatty Acids; D007850:Lauric Acids; D010169:Palmitic Acids; D028044:Phosphate-Binding Proteins; D010710:Phosphates