The plasma membrane H(+) ATPase of plants and fungi generates a proton gradient that drives the active transport of nutrients by H(+)-symport. The resulting external acidification and/or internal alkinization may mediate growth responses. ATP + H(+)(in) + H2O = ADP + 2 H(+)(out) + phosphate Binds to 14-3-3 proteins. The binding is induced by phosphorylation of Thr-948. Binding to 14-3-3 proteins activates the H(+)-ATPase. Found predominantly in phloem cells of leaves, stems, roots and flowers. Phosphorylation level varies significantly during early response to bacterial elicitor (e.g. fusicoccin FC). Belongs to the cation transport ATPase (P-type) (TC 3.A.3) family. Type IIIA subfamily.