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

被引：158

作者：

Chérel, I ^{[1
]}

Michard, E ^{[1
]}

Platet, N ^{[1
]}

Mouline, K ^{[1
]}

Alcon, C ^{[1
]}

Sentenac, H ^{[1
]}

Thibaud, JB ^{[1
]}

机构：

[1] Univ Montpellier 2, INRA, Lab Biochim & Physiol Mol Plantes, CNRS,Unite Mixte Rech 5004 AgroM, F-34060 Montpellier 1, France

来源：

PLANT CELL | 2002年 / 14卷 / 05期

关键词：

D O I：

10.1105/tpc.000943

中图分类号：

Q5 [生物化学]; Q7 [分子生物学];

学科分类号：

071010 ; 081704 ;

摘要：

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.

引用

页码：1133 / 1146

页数：14

共 73 条

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