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PMID: 12034902 Published · ppublish English Journal Article

Physical and functional interaction of the Arabidopsis K(+) channel AKT2 and phosphatase AtPP2CA.

The Plant cell ·Vol. 14 ·No. 5 ·2002-05-00 ·Pages 1133-46

Chérel I, Michard E, Platet N, Mouline K, Alcon C, Sentenac H, Thibaud JB

Abstract

The AKT2 K(+) channel is endowed with unique functional properties, being the only weak inward rectifier characterized to date in Arabidopsis. The gene is expressed widely, mainly in the phloem but also at lower levels in leaf epiderm, mesophyll, and guard cells. The AKT2 mRNA level is upregulated by abscisic acid. By screening a two-hybrid cDNA library, we isolated a protein phosphatase 2C (AtPP2CA) involved in abscisic acid signaling as a putative partner of AKT2. We further confirmed the interaction by in vitro binding studies. The expression of AtPP2CA (beta-glucuronidase reporter gene) displayed a pattern largely overlapping that of AKT2 and was upregulated by abscisic acid. Coexpression of AtPP2CA with AKT2 in COS cells and Xenopus laevis oocytes was found to induce both an inhibition of the AKT2 current and an increase of the channel inward rectification. Site-directed mutagenesis and pharmacological analysis revealed that this functional interaction involves AtPP2CA phosphatase activity. Regulation of AKT2 activity by AtPP2CA in planta could allow the control of K(+) transport and membrane polarization during stress situations.

MeSH Terms
Abscisic Acid/pharmacology Animals Arabidopsis/enzymology,genetics,physiology Arabidopsis Proteins COS Cells DNA, Complementary Gene Expression Regulation, Enzymologic/drug effects Gene Expression Regulation, Plant/drug effects Oocytes/physiology Phosphoprotein Phosphatases/genetics,metabolism Plant Epidermis/enzymology,genetics,physiology Plant Proteins/genetics,metabolism Plant Roots/enzymology,genetics,physiology Plant Shoots/enzymology,genetics,physiology Potassium Channels/genetics,metabolism Protein Binding Protein Phosphatase 2 Protein Phosphatase 2C RNA, Messenger/metabolism Saccharomyces cerevisiae Proteins Signal Transduction Two-Hybrid System Techniques Xenopus laevis
Chemicals
AKT2 protein, Arabidopsis Arabidopsis Proteins DNA, Complementary Plant Proteins Potassium Channels RNA, Messenger Saccharomyces cerevisiae Proteins Abscisic Acid AHG3 protein, Arabidopsis PTC1 protein, S cerevisiae Phosphoprotein Phosphatases Protein Phosphatase 2 Protein Phosphatase 2C
Authors & Affiliations
7 authors, click to expand affiliations / ORCID
Chérel Isabelle
Laboratoire de Biochimie et Physiologie Moléculaire des Plantes, Unité Mixte de Recherche 5004 Agro-M/Centre National de la Recherche Scientifique/Institut National de la Recherche Agronomique/Université Montpellier II, France. cherel@ensam.inra.fr
Michard Erwan
Platet Nadine
Mouline Karine
Alcon Carine
Sentenac Hervé
Thibaud Jean-Baptiste
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Article Info
Journal
The Plant cell
Abbr.
Plant Cell
ISSN
1040-4651
DOI
10.1105/tpc.000943
Email
cherel@ensam.inra.fr
Published
2002-05-00
Pages
1133-46
Language
English
Region
England
NLM ID
9208688
PMCID
PMC150612
Subset
IM
External Links
PubMed source DOI: 10.1105/tpc.000943 PMC Full Text View journal details
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