Abstract
The Arabidopsis ABI1 locus is essential for a wide spectrum of abscisic acid (ABA) responses throughout plant development. Here, ABI1 was shown to regulate stomatal aperture in leaves and mitotic activity in root meristems. The ABI1 gene was cloned and predicted to encode a signaling protein. Although its carboxyl-terminal domain is related to serine-threonine phosphatase 2C, the ABI1 protein has a unique amino-terminal extension containing an EF hand calcium-binding site. These results suggest that the ABI1 protein is a Ca(2+)-modulated phosphatase and functions to integrate ABA and Ca2+ signals with phosphorylation-dependent response pathways.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Abscisic Acid / pharmacology*
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Amino Acid Sequence
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Arabidopsis / chemistry
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Arabidopsis / cytology
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Arabidopsis / genetics*
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Arabidopsis / physiology
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Arabidopsis Proteins*
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Calcium / metabolism*
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Cloning, Molecular
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Genes, Plant*
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Mitosis
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Molecular Sequence Data
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Mutation
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Phenotype
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Phosphoprotein Phosphatases / chemistry
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Phosphoprotein Phosphatases / genetics*
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Phosphoprotein Phosphatases / metabolism*
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Phosphorylation
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Plants, Genetically Modified
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Polymorphism, Restriction Fragment Length
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Signal Transduction
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Transformation, Genetic
Substances
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Arabidopsis Proteins
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Abscisic Acid
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ABI1 protein, Arabidopsis
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Phosphoprotein Phosphatases
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Calcium