CPK13, A noncanonical Ca2+-Dependent protein kinase, Specifically inhibits KAT2 and KAT1 shaker K+channels and reduces stomatal opening

Elsa Ronzier, Claire Corratgé-Faillie, FréDéRic Sanchez, Karine Prado, Christian Brière, Nathalie Leonhardt, Jean Baptiste Thibaud, Tou Cheu Xiong*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

87 Scopus citations

Abstract

Ca2+-dependent protein kinases (CPKs) form a large family of 34 genes in Arabidopsis (Arabidopsis thaliana). Based on their dependence on Ca2+, CPKs can be sorted into three types: strictly Ca2+-dependent CPKs, Ca2+-stimulated CPKs (with a significant basal activity in the absence of Ca2+), and essentially calcium-insensitive CPKs. Here, we report on the third type of CPK, CPK13, which is expressed in guard cells but whose role is still unknown. We confirm the expression of CPK13 in Arabidopsis guard cells, and we show that its overexpression inhibits light-induced stomatal opening. We combine several approaches to identify a guard cell-expressed target. We provide evidence that CPK13 (1) specifically phosphorylates peptide arrays featuring Arabidopsis K+ Channel KAT2 and KAT1 polypeptides, (2) inhibits KAT2 and/or KAT1 when expressed in Xenopus laevis oocytes, and (3) closely interacts in plant cells with KAT2 channels (Förster resonance energy transfer-fluorescence lifetime imaging microscopy). We propose that CPK13 reduces stomatal aperture through its inhibition of the guard cellexpressed KAT2 and KAT1 channels.

Original languageEnglish
Pages (from-to)314-326
Number of pages13
JournalPlant Physiology
Volume166
Issue number1
DOIs
StatePublished - 1 Sep 2014
Externally publishedYes

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