This Article Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Dreyer, I. Articles by Mueller-Roeber, B. Search for Related Content PubMed PubMed Citation Articles by Dreyer, I. Articles by Mueller-Roeber, B.

Assembly of Plant Shaker-Like K_out Channels Requires Two Distinct Sites of the Channel -Subunit

Ingo Dreyer ^*  , Fabien Porée ^*  , Antje Schneider  , Jessica Mittelstädt , Adam Bertl , Hervé Sentenac ^*, Jean-Baptiste Thibaud ^* and Bernd Mueller-Roeber  

^* Biochimie et Physiologie Moléculaires des Plantes, UMR 5004, Agro-M/CNRS/INRA/UM2, F-34060 Montpellier Cedex 1, France; Universität Potsdam, Institut für Biochemie und Biologie, Abteilung Molekularbiologie, D-14476 Golm/Potsdam, Germany; Max-Planck Institute of Molecular Plant Physiology, Cooperative Research Group, D-14476 Golm/Potsdam, Gemany; and Botanisches Institut I, Universität Karlsruhe, 76128 Karlsruhe, Germany

Correspondence: Address reprint requests to Ingo Dreyer, Universität Potsdam, Institut für Biochemie und Biologie, Abteilung Molekularbiologie, Karl-Liebknecht-Strasse 24-25, Haus 20, D-14476 Golm/Potsdam, Germany. Fax: 49-331-977-2512; E-mail: dreyer{at}rz.uni-potsdam.de.

SKOR and GORK are outward-rectifying plant potassium channels from Arabidopsis thaliana. They belong to the Shaker superfamily of voltage-dependent K⁺ channels. Channels of this class are composed of four -subunits and subunit assembly is a prerequisite for channel function. In this study the assembly mechanism of SKOR was investigated using the yeast two-hybrid system and functional assays in Xenopus oocytes and in yeast. We demonstrate that SKOR and GORK physically interact and assemble into heteromeric K_out channels. Deletion mutants and chimeric proteins generated from SKOR and the K_in channel -subunit KAT1 revealed that the cytoplasmic C-terminus of SKOR determines channel assembly. Two domains that are crucial for channel assembly were identified: i), a proximal interacting region comprising a putative cyclic nucleotide-binding domain together with 33 amino acids just upstream of this domain, and ii), a distal interacting region showing some resemblance to the K_T domain of KAT1. Both regions contributed differently to channel assembly. Whereas the proximal interacting region was found to be active on its own, the distal interacting region required an intact proximal interacting region to be active. K_out -subunits did not assemble with K_in -subunits because of the absence of interaction between their assembly sites.

This article has been cited by other articles:

				J. Xicluna, B. Lacombe, I. Dreyer, C. Alcon, L. Jeanguenin, H. Sentenac, J.-B. Thibaud, and I. Cherel Increased Functional Diversity of Plant K+ Channels by Preferential Heteromerization of the Shaker-like Subunits AKT2 and KAT2 J. Biol. Chem., January 5, 2007; 282(1): 486 - 494. [Abstract] [Full Text] [PDF]

				A. Naso, R. Montisci, F. Gambale, and C. Picco Stoichiometry Studies Reveal Functional Properties of KDC1 in Plant Shaker Potassium Channels Biophys. J., November 15, 2006; 91(10): 3673 - 3683. [Abstract] [Full Text] [PDF]

				M. K. Ashley, M. Grant, and A. Grabov Plant responses to potassium deficiencies: a role for potassium transport proteins J. Exp. Bot., January 1, 2006; 57(2): 425 - 436. [Abstract] [Full Text] [PDF]