To investigate the mechanism by which fusicoccin (FC) induces the activation of the plasma membrane (PM) H+-ATPase, we used phenylarsine oxide (PAO), a known inhibitor of protein tyrosine-phosphatases. PAO was supplied in vivo in the absence or presence of FC to radish (Raphanus sativus L.) seedlings and cultured Arabidopsis cells prior to PM extraction. Treatment with PAO alone caused a slight decrease of PM H+-ATPase activity and, in radish, a decrease of PM-associated 14-3-3 proteins. When supplied prior to FC, PAO drastically inhibited FC-induced activation of PM H+-ATPase, FC binding to the PM, and the Pc-induced increase of the amount of 14-3-3 associated with the PM. On the contrary, PAO was completely ineffective on all of the above-mentioned parameters when supplied after FC. The H+-ATPase isolated from PAO-treated Arabidopsis cells maintained the ability to respond to FC if supplied with exogenous, nonphosphorylated 14-3-3 proteins. Altogether, these results are consistent with a model in which the dephosphorylated state of tyrosine residues of a protein(s), such as 14-3-3 protein, is required to permit FC-induced association between the 14-3-3 protein and the PM H+-ATPase.

Phenylarsine oxide inhibits the fusicoccin-induced activation of plasma membrane H+-ATPase / C. Olivari, C. Albumi, M.C. Pugliarello, M.I. De Michelis. - In: PLANT PHYSIOLOGY. - ISSN 0032-0889. - 122:2(2000), pp. 463-470.

Phenylarsine oxide inhibits the fusicoccin-induced activation of plasma membrane H+-ATPase

C. Olivari
Primo
;
M.I. De Michelis
Ultimo
2000

Abstract

To investigate the mechanism by which fusicoccin (FC) induces the activation of the plasma membrane (PM) H+-ATPase, we used phenylarsine oxide (PAO), a known inhibitor of protein tyrosine-phosphatases. PAO was supplied in vivo in the absence or presence of FC to radish (Raphanus sativus L.) seedlings and cultured Arabidopsis cells prior to PM extraction. Treatment with PAO alone caused a slight decrease of PM H+-ATPase activity and, in radish, a decrease of PM-associated 14-3-3 proteins. When supplied prior to FC, PAO drastically inhibited FC-induced activation of PM H+-ATPase, FC binding to the PM, and the Pc-induced increase of the amount of 14-3-3 associated with the PM. On the contrary, PAO was completely ineffective on all of the above-mentioned parameters when supplied after FC. The H+-ATPase isolated from PAO-treated Arabidopsis cells maintained the ability to respond to FC if supplied with exogenous, nonphosphorylated 14-3-3 proteins. Altogether, these results are consistent with a model in which the dephosphorylated state of tyrosine residues of a protein(s), such as 14-3-3 protein, is required to permit FC-induced association between the 14-3-3 protein and the PM H+-ATPase.
C-TERMINAL REGION ; TYROSINE PHOSPHORYLATION ; PROTEIN-KINASES ; ABSCISIC-ACID; AUTOINHIBITORY DOMAIN ; ARABIDOPSIS-THALIANA ; SIGNAL-TRANSDUCTION ; BINDING COMPLEX ; PUMPING DRIVEN ; MAP KINASE
Settore BIO/04 - Fisiologia Vegetale
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Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/2434/142655
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