Energy coupling of L-glutamate transport and vacuolar H(+)-ATPase in brain synaptic vesicles.
Energy coupling of L-glutamate transport in brain synaptic vesicles has been studied. ATP-dependent acidification of the bovine brain synaptic vesicles was shown to require CI-, to be accelerated by valinomycin and to be abolished by ammonium sulfate, nigericin or CCCP plus valinomycin, and K+. On the other hand, ATP-driven formation of a membrane potential (positive inside) was found to be stimulated by ammonium sulfate, not to be affected by nigericin and to be abolished by CCCP plus valinomycin and K+. Like formation of a membrane potential, ATP-dependent L-[3H]glutamate uptake into vesicles was stimulated by ammonium sulfate, not affected by nigericin and abolished by CCCP plus valinomycin and K+. The L-[3H]glutamate uptake differed in specificity from the transport system in synaptic plasma membranes. Both ATP-dependent H+ pump activity and L-glutamate uptake were inhibited by bafilomycin and cold treatment (common properties of vacuolar H(+)-ATPase). ATP-dependent acidification in the presence of L-glutamate was also observed, suggesting that L-glutamate uptake lowered the membrane potential to drive further entry of H+. These results were consistent with the notion that the vacuolar H(+)-ATPase of synpatic vesicles formed a membrane potential to drive L-glutamate uptake. ATPase activity of the vesicles was not affected by the addition of Cl-, glutamate or nigericin, indicating that an electrochemical H+ gradient had no effect on the ATPase activity.
Moriyama
Y
Y
Department of Biochemistry and Organic Chemistry, Institute of Scientific and Industrial Research, Osaka University.
Maeda
M
M
Futai
M
M
D000255:Adenosine Triphosphate / Q000494:pharmacology; D000645:Ammonium Sulfate / Q000494:pharmacology; D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D001692:Biological Transport; D001921:Brain / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism*; D002258:Carbonyl Cyanide m-Chlorophenyl Hydrazone / Q000494:pharmacology; D002417:Cattle; D005971:Glutamates / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D018942:Macrolides; D008564:Membrane Potentials; D009550:Nigericin / Q000494:pharmacology; D006180:Proton-Translocating ATPases / Q000378:metabolism*; D013572:Synaptic Vesicles / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism*; D014617:Vacuoles / Q000201:enzymology; D014634:Valinomycin / Q000494:pharmacology
D000900:Anti-Bacterial Agents; D005971:Glutamates; D018942:Macrolides; C057620:bafilomycin A; D014634:Valinomycin; D002258:Carbonyl Cyanide m-Chlorophenyl Hydrazone; D000255:Adenosine Triphosphate; D006180:Proton-Translocating ATPases; D009550:Nigericin; D000645:Ammonium Sulfate