Short communication: unsaturated fatty acids inhibit MP2C, a protein phosphatase 2C involved in the wound-induced MAP kinase pathway regulation.
When mechanically injured, plants develop multiple defense systems including the activation of specific genes. These responses are triggered by a complex network of signalling events that include Ca2+ fluxes, the production of free fatty acids from membrane lipids, as well as the activation of mitogen-activated protein kinases (MAPK). In the present paper, we address the question of the regulation of the MAPK pathway by wound-induced Ca2+ and fatty acid signals. We report that MP2C, a serine/threonine protein phosphatase 2C from alfalfa involved in MAPK pathway inactivation, is inhibited specifically in vitro by long-carbon-chain polyunsaturated fatty acids, and alpha-linolenic acid, the primary product of the octadecanoid pathway, was found to be the most potent inhibitor. Ca2+ also inhibits MP2C, but only at high concentrations, and other divalent cations show similar inhibitory effect, making it unlikely that Ca2+ is involved in the regulation of MP2C in vivo. Overall, our data suggest that cross-talk between wound-induced MAPK and octadecanoid pathways may occur at the level of protein phosphatase 2C and linolenic acid.
Baudouin
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E
Institute of Microbiology and Genetics, Vienna Biocenter, University of Vienna, Austria.
Meskiene
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I
Hirt
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H
D002118:Calcium / Q000494:pharmacology / Q000502:physiology; D005231:Fatty Acids, Unsaturated / Q000494:pharmacology / Q000502:physiology*; D020935:MAP Kinase Signaling System / Q000502:physiology*; D000455:Medicago sativa / Q000502:physiology*; D010749:Phosphoprotein Phosphatases / Q000037:antagonists & inhibitors* / Q000378:metabolism; D054648:Protein Phosphatase 2; D000071636:Protein Phosphatase 2C; D029701:Saccharomyces cerevisiae Proteins; D017962:alpha-Linolenic Acid / Q000494:pharmacology
D005231:Fatty Acids, Unsaturated; D029701:Saccharomyces cerevisiae Proteins; D017962:alpha-Linolenic Acid; C087358:PTC1 protein, S cerevisiae; D010749:Phosphoprotein Phosphatases; D054648:Protein Phosphatase 2; D000071636:Protein Phosphatase 2C; D002118:Calcium