Role of the plasma membrane H+-ATPase in K+ transport

Donald P. Briskin, Margaret C. Gawienowski

Research output: Contribution to journalArticlepeer-review


The role of the plant plasma membrane H+-ATPase in K+ uptake was examined using red beet (Beta vulgaris L.) plasma membrane vesicles and a partially purified preparation of the red beet plasma membrane H+ -ATPase reconstituted in proteoliposomes and planar bilayers. For plasma membrane vesicles, ATP-dependent K+ efflux was only partially inhibited by 100 μM vanadate or 10 μM carbonyl cyanide-p-trifluoromethoxyphenylhydrazone. However, full inhibition of ATP-dependent K+ efflux by these reagents occurred when the red beet plasma membrane H+-ATPase was partially purified and reconstituted in proteoliposomes. When reconstituted in a planar bilayer membrane, the current/voltage relationship for the plasma membrane H+-ATPase showed little effect of K+ gradients imposed across the bilayer membrane. When taken together, the results of this study demonstrate that the plant plasma membrane H+-ATPase does not mediate direct K+ transport chemically linked to ATP hydrolysis. Rather, this enzyme provides a driving force for cellular K+ uptake by secondary mechanisms, such as K+ channels or H+/K+ symporters. Although the presence of a small, protonophoreinsensitive component of ATP-dependent K+ transport in a plasma membrane fraction might be mediated by an ATP-activated K+ channel, the possibility of direct K+ transport by other ATPases (i.e. K+-ATPases) associated with either the plasma membrane or other cellular membranes cannot be ruled out.

Original languageEnglish (US)
Pages (from-to)1199-1207
Number of pages9
JournalPlant physiology
Issue number4
StatePublished - Aug 1996

ASJC Scopus subject areas

  • Physiology
  • Genetics
  • Plant Science


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