The 14-3-3 proteins associate with the plant plasma membrane H+-ATPase to generate a fusicoccin binding complex and a fusicoccin responsive system

• Published in: The Plant journal : for cell and molecular biology Vol. 13; no. 5; pp. 661 - 671
• Main Authors: BAUNSGAARD, L, FUGLSANG, A. T, JAHN, T, KORTHOUT, H. A. A. J, DE BOER, A. H, PALMGREN, M. G
• Format: Journal Article
• Language: English
• Published: Oxford Blackwell Science 01-03-1998
• Subjects: 14-3-3 Proteins; Amino Acid Sequence; Arabidopsis - enzymology; Arabidopsis - genetics; Base Sequence; Biological and medical sciences; Cell Membrane - enzymology; Cell physiology; DNA Primers - genetics; Enzyme Activation - drug effects; Fundamental and applied biological sciences. Psychology; Glycosides - metabolism; Glycosides - pharmacology; Molecular Sequence Data; Peptide Fragments - genetics; Peptide Fragments - metabolism; Peptide Fragments - pharmacology; Plant physiology and development; Plant Proteins - genetics; Plant Proteins - metabolism; Plasma membrane and permeation; Protein Binding; Proteins - genetics; Proteins - metabolism; Proton-Translocating ATPases - genetics; Proton-Translocating ATPases - metabolism; Receptors, Cell Surface - metabolism; Saccharomyces cerevisiae - genetics; Saccharomyces cerevisiae - metabolism; Tyrosine 3-Monooxygenase; Recombinant microorganism; Enzyme; Glucoside; H; Activation; transporting ATPase; Fungi; Arabidopsis thaliana; Fixation; Cruciferae; Dicotyledones; Angiospermae; Plasma membrane; Hydrolases; Plant growth substance; Ascomycetes; Spermatophyta; Experimental plant; Mechanism of action; Saccharomyces cerevisiae; Thallophyta; Biological receptor
• ISSN: 0960-7412; 1365-313X
• DOI: 10.1046/j.1365-313X.1998.00083.x

The plasma membrane H(+)-ATPase in higher plants has been implicated in nutrient uptake, phloem loading, elongation growth and establishment of turgor. Although a C-terminal regulatory domain has been identified, little is known about the physiological factors involved in controlling the activity of the enzyme. To identify components which play a role in the regulation of the plant H(+)-ATPase, a fusicoccin responsive yeast expressing Arabidopsis plasma membrane H(+)-ATPase AHA2 was employed. By testing the fusicoccin binding activity of yeast membranes, the C-terminal regulatory domain of AHA2 was found to be part of a functional fusicoccin receptor, a component of which was the 14-3-3 protein. ATP hydrolytic activity of AHA2 expressed in yeast internal membranes was activated by all tested isoforms of the 14-3-3 protein of yeast and Arabidopsis, but only in the presence of fusicoccin, and activation was prevented by a phosphoserine peptide representing a known 14-3-3 protein binding motif in Raf-1. The results demonstrate that the 14-3-3 protein is an activator molecule of the H(+)-ATPase and provides the first evidence of a protein involved in activation of plant plasma membrane H(+)-ATPase.