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Hydrogen peroxide is a regulator of ABI1, a protein phosphatase 2C from Arabidopsis
Author(s) -
Meinhard Michael,
Grill Erwin
Publication year - 2001
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/s0014-5793(01)03106-4
Subject(s) - arabidopsis , chemistry , phenylarsine oxide , phosphatase , biochemistry , hydrogen peroxide , arabidopsis thaliana , regulator , second messenger system , microbiology and biotechnology , cysteine , enzyme , biology , mutant , gene
Protein phosphatases 2C (PP2Cs) exhibit diverse regulatory functions in signalling pathways of animals, yeast and plants. ABI1 is a PP2C of Arabidopsis that exerts negative control on signalling of the phytohormone abscisic acid (ABA). Characterisation of the redox sensitivity of ABI1 revealed a strong enzymatic inactivation by hydrogen peroxide (H 2 O 2 ) which has recently been implicated as a secondary messenger of ABA signalling. H 2 O 2 reversibly inhibited ABI1 activity in vitro with an IC 50 of approximately 140 μM in the presence of physiological concentrations of glutathione. In addition, ABI1 was highly susceptible to inactivation by phenylarsine oxide (IC 50 =3–4 μM) indicative for the facile oxidation of vicinal cysteine residues. Thus, H 2 O 2 generated during ABA signalling seems to inactivate the negative regulator of the ABA response.