期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：1983
卷号：80
期号：5
页码：1300-1303
DOI：10.1073/pnas.80.5.1300
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：Clathrin-coated vesicles isolated from calf brain contain an ATP-dependent proton pump. Proton movement was monitored by measuring [14C]methylamine distribution. Addition of Mg2+ and ATP to coated vesicles equilibrated with [14C]methylamine resulted in the generation of a 4- to 5-fold concentration gradient, corresponding to a delta pH of 0.6-0.7 units between the medium and the acidic inside of the coated vesicles. ATP-dependent [14C]methylamine uptake was abolished by the proton ionophore carbonylcyanide p-trifluoromethoxyphenylhydrazone (FCCP) and partially inhibited by the carboxyl reagent N,N'-dicyclohexylcarbodiimide but was unaffected by the Na+, K+-ATPase inhibitors strophanthidin (100 microM) and vanadate (10 microM) and the mitochondrial ATPase inhibitors oligomycin (10 microgram/ml) and aurovertin (1 microgram/ml). GTP, but not the nonhydrolyzable analog 5'-adenylyl imidodiphosphate, could support [14C]methylamine uptake. Dissipation of the membrane potential with K+ and valinomycin resulted in stimulation of [14C]methylamine uptake, whereas both FCCP and valinomycin stimulated the strophanthidin-resistant ATPase activity. These results are consistent with the existence of an electrogenic, ATP-dependent proton pump in clathrin-coated vesicles. This proton pump may play a role in the acidification events that are essential in receptor-mediated endocytosis.
