title: Is Zn2+ transported by the mitochondrial calcium uniporter?
abstract: Zinc ions were found to inhibit Ca2+ uptake by rat liver mitochondria driven by succinate respiration but not that by a valinomycin-induced membrane potential. Zn2+ at 1 microM or higher concentrations induced a lowering of the membrane potential under the former but not the latter conditions. It is concluded that it is the lowered membrane potential in the presence of Zn2+ that reduces the rate of respiration-driven Ca2+. Ruthenium red was found to inhibit the uptake of Zn2+ but had no influence on its action upon the membrane potential. Zn2+ did not affect the Ruthenium red-insensitive Ca2+ efflux. Ca2+ stimulated the uptake of Zn2+. It is concluded that Zn2+ may be transported by the mitochondrial calcium uniporter but that it may have access to sites required for inhibition of respiration by other routes.
authors.affiliation: Department of Medical Chemistry, University of Helsinki, Finland.
authors.forename: N E
authors.initials: NE
authors.lastname: Saris
authors.forename: K
authors.initials: K
authors.lastname: Niva
mesh_terms: D000818:Animals; D002118:Calcium / Q000378:metabolism / Q000494:pharmacology; D015220:Calcium Channels; D002135:Calcium-Binding Proteins / Q000378:metabolism*; D004305:Dose-Response Relationship, Drug; D007425:Intracellular Membranes / Q000187:drug effects / Q000502:physiology*; D007700:Kinetics; D008564:Membrane Potentials / Q000187:drug effects; D008930:Mitochondria, Liver / Q000378:metabolism*; D010101:Oxygen Consumption; D051381:Rats; D012430:Ruthenium Red / Q000494:pharmacology; D013386:Succinates / Q000378:metabolism; D015032:Zinc / Q000378:metabolism* / Q000494:pharmacology
chemical_list: D015220:Calcium Channels; D002135:Calcium-Binding Proteins; D013386:Succinates; C034703:mitochondrial calcium uniporter; D012430:Ruthenium Red; D015032:Zinc; D002118:Calcium