A protein kinase, interacting with two calcineurin B-like proteins, regulates K+ transporter AKT1 in Arabidopsis.
Potassium is an essential mineral element for plant growth and development. Although it is known that plants absorb and transport K+ through membrane transporters, it remains unclear how these transporters are regulated. Here we show that the protein kinase CIPK23, encoded by the LKS1 gene, regulates K+ uptake under low-K+ ... conditions. Lesion of LKS1 significantly reduced K+ uptake and caused leaf chlorosis and growth inhibition, whereas overexpression of LKS1 significantly enhanced K+ uptake and tolerance to low K+. We demonstrate that CIPK23 directly phosphorylates the K+ transporter AKT1 and further find that CIPK23 is activated by the binding of two calcineurin B-like proteins, CBL1 and CBL9. We propose a model in which the CBL1/9-CIPK23 pathway ensures activation of AKT1 and enhanced K+ uptake under low-K+ conditions.
Mesh Terms:
Animals, Arabidopsis, Arabidopsis Proteins, Base Sequence, Biological Transport, Active, Calcium-Binding Proteins, DNA, Plant, Female, Genes, Plant, Ion Transport, Models, Biological, Mutagenesis, Mutation, Oocytes, Phenotype, Plants, Genetically Modified, Potassium, Potassium Channels, Protein-Serine-Threonine Kinases, Recombinant Proteins, Xenopus laevis
Animals, Arabidopsis, Arabidopsis Proteins, Base Sequence, Biological Transport, Active, Calcium-Binding Proteins, DNA, Plant, Female, Genes, Plant, Ion Transport, Models, Biological, Mutagenesis, Mutation, Oocytes, Phenotype, Plants, Genetically Modified, Potassium, Potassium Channels, Protein-Serine-Threonine Kinases, Recombinant Proteins, Xenopus laevis
Cell
Date: Jun. 30, 2006
PubMed ID: 16814720
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