HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

J. Biol. Chem., Vol. 281, Issue 50, 38285-38292, December 15, 2006

This Article Full Text Full Text (PDF) Supplemental Data All Versions of this Article: 281/50/38285    most recent M604781200v1 Submit a Letter to Editor Alert me when this article is cited Alert me when eLetters are posted Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Request Permissions Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Buch-Pedersen, M. J. Articles by Palmgren, M. G. Search for Related Content PubMed PubMed Citation Articles by Buch-Pedersen, M. J. Articles by Palmgren, M. G. Social Bookmarking                      What's this?

Potassium as an Intrinsic Uncoupler of the Plasma Membrane H⁺-ATPase^*

From the Department of Plant Biology, The Royal Veterinary and Agricultural University, Thorvaldsensvej 40, DK-1871 Frederiksberg C, Copenhagen, Denmark

The plant plasma membrane proton pump (H⁺-ATPase) is stimulated by potassium, but it has remained unclear whether potassium is actually transported by the pump or whether it serves other roles. We now show that K⁺ is bound to the proton pump at a site involving Asp⁶¹⁷ in the cytoplasmic phosphorylation domain, from where it is unlikely to be transported. Binding of K⁺ to this site can induce dephosphorylation of the phosphorylated E₁P reaction cycle intermediate by a mechanism involving Glu¹⁸⁴ in the conserved TGES motif of the pump actuator domain. Our data identify K⁺ as an intrinsic uncoupler of the proton pump and suggest a mechanism for control of the H⁺/ATP coupling ratio. K⁺-induced dephosphorylation of E₁P may serve regulatory purposes and play a role in negative regulation of the transmembrane electrochemical gradient under cellular conditions where E₁P is accumulating.

Received for publication, May 18, 2006 , and in revised form, September 18, 2006.

^* This work was supported by the European Union's Framework 6 Program, a fellowship from the Danish Carlsberg Foundation (to M. B. P.), and a fellowship from the Danish Ministry of Education (to E. L. R.). The costs of publication of this article were defrayed in part by the payment of page charges. This article must therefore be hereby marked "advertisement" in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.

The on-line version of this article (available at http://www.jbc.org) contains a supplemental figure.

¹ To whom correspondence should be addressed. Tel.: 45 3528 2595; Fax: 45 3528 3365; E-mail: mob{at}kvl.dk.

CiteULike    Complore    Connotea    Del.icio.us    Digg    Reddit    Technorati    What's this?

This article has been cited by other articles:

				G. Duby, W. Poreba, D. Piotrowiak, K. Bobik, R. Derua, E. Waelkens, and M. Boutry Activation of Plant Plasma Membrane H+-ATPase by 14-3-3 Proteins Is Negatively Controlled by Two Phosphorylation Sites within the H+-ATPase C-terminal Region J. Biol. Chem., February 13, 2009; 284(7): 4213 - 4221. [Abstract] [Full Text] [PDF]

				V. R. Schack, J. P. Morth, M. S. Toustrup-Jensen, A. N. Anthonisen, P. Nissen, J. P. Andersen, and B. Vilsen Identification and Function of a Cytoplasmic K+ Site of the Na+, K+-ATPase J. Biol. Chem., October 10, 2008; 283(41): 27982 - 27990. [Abstract] [Full Text] [PDF]

				Y. A. Mahmmoud Capsazepine, a synthetic vanilloid that converts the Na,K-ATPase to Na-ATPase PNAS, February 5, 2008; 105(5): 1757 - 1761. [Abstract] [Full Text] [PDF]