Tobacco MAP Kinase: A Possible Mediator in Wound Signal Transduction Pathways

Seo, Shigemi; Okamoto, Masanori; Seto, Hideharu; Ishizuka, Koko; Sano, Hiroshi; Ohashi, Yuko

doi:10.1126/science.270.5244.1988

Cited by 510 publications

(474 citation statements)

References 56 publications

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“…Reversible protein phosphorylation is known to be involved in the regulation of wound signaling in plants and has even been reported to influence JA levels, as well as JA-responsive gene expression (37)(38)(39)(40)(41). A role of posttranslational modifications in the regulation of the JA biosynthesis itself is supported by the observation that JA begins to accumulate almost instantly after wounding, whereas maximum transcript levels of induced genes coding for enzymes of JA biosynthesis are reached only after 2 h (10,42,43).…”

Section: Homodimerization In Solutionsupporting

confidence: 48%

Crystal structure of 12-oxophytodienoate reductase 3 from tomato: Self-inhibition by dimerization

Breithaupt

Kurzbauer

Lilie

et al. 2006

Proc. Natl. Acad. Sci. U.S.A.

119

109

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12-Oxophytodienoate reductase (OPR) 3, a homologue of old yellow enzyme (OYE), catalyzes the reduction of 9S,13S-12-oxophytodienoate to the corresponding cyclopentanone, which is subsequently converted to the plant hormone jasmonic acid (JA). JA and JA derivatives, as well as 12-oxophytodienoate and related cyclopentenones, are known to regulate gene expression in plant development and defense. Together with other oxygenated fatty acid derivatives, they form the oxylipin signature in plants, which resembles the pool of prostaglandins in animals. Here, we report the crystal structure of OPR3 from tomato and of two OPR3 mutants. Although the catalytic residues of OPR3 and related OYEs are highly conserved, several characteristic differences can be discerned in the substrate-binding regions, explaining the remarkable substrate stereoselectivity of OPR isozymes. Interestingly, OPR3 crystallized as an extraordinary self-inhibited dimer. Mutagenesis studies and biochemical analysis confirmed a weak dimerization of OPR3 in vitro, which correlated with a loss of enzymatic activity. Based on structural data of OPR3, a putative mechanism for a strong and reversible dimerization of OPR3 in vivo that involves phosphorylation of OPR3 is suggested. This mechanism could contribute to the shaping of the oxylipin signature, which is critical for fine-tuning gene expression in plants.flavoprotein ͉ jasmonic acid biosynthesis ͉ plant defense ͉ oxylipin signature ͉ 12-oxophytodienoic acid F lavoproteins catalyze a wide variety of essential biochemical reactions, including electron transfer, dehydrogenation, and hydroxylation reactions. Old yellow enzyme (OYE), the first flavin-dependent enzyme identified (1), and homologues of OYE from bacteria, yeast, and plants are able to reduce the CAC double bond of ␣,␤-unsaturated carbonyl compounds, an activity that is rather uncommon for flavoenzymes (2, 3). This reaction has been shown to proceed by a ping-pong bi-bi mechanism, during which the FMN cofactor is reduced by NAD(P)H before the substrate is bound and reduced by hydride transfer to the substrate's C ␤ (4). Despite extensive efforts, the physiological substrate has been revealed only for one member of the OYE family, the plant enzyme 12-oxophytodienoate reductase (OPR) 3, which catalyzes one step in the biosynthesis of the plant hormone jasmonic acid (JA) (5, 6). JA and JA derivatives act as signaling compounds in the defense response against herbivores and pathogens and are involved in the regulation of various developmental processes, such as fruit ripening, pollen maturation, and senescence (7,8). JA is synthesized from ␣-linolenic acid, which is oxidized and cyclized, resulting in the cyclopentenone 9S,13S-12-oxophytodienoate (9S,13S-OPDA). OPR3 reduces 9S,13S-OPDA to the corresponding cyclopentanone, which is converted to JA by repeated ␤-oxidation ( Fig. 1) (9). Several OPR isozymes have been identified in plants, including 3 isoforms in Lycopersicon esculentum, 5 in Arabidopsis thaliana, and 13 in Oryza sativa (10, 11). O...

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Section: Homodimerization In Solutionsupporting

confidence: 48%

Crystal structure of 12-oxophytodienoate reductase 3 from tomato: Self-inhibition by dimerization

Breithaupt

Kurzbauer

Lilie

et al. 2006

Proc. Natl. Acad. Sci. U.S.A.

119

109

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“…6). Tyr phosphorylation has been implicated in the activation of other plant MBP kinases as well (Seo et al, 1995;Suzuki and Shinshi, 1995;Usami et al, 1995;Knetsch et al, 1996;Zhang and Klessig, 1997). Further confirmation of Tyr phosphorylation of HAPK through in vivo labeling, immunoidentification of P Tyr residues, or molecular sequencing of the HAPK will be necessary to establish conclusively the identity of HAPK as a MAPK.…”

Section: Discussionmentioning

confidence: 99%

Rapid and Transient Activation of a Myelin Basic Protein Kinase in Tobacco Leaves Treated with Harpin from Erwinia amylovora

et al. 1997

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85-88). Activity of a 49-kD Mg2+-dependent and Caz+-independent kinase in tobacco leaves increased 50-fold 15 min after infiltration of harpin from Erwinia amylovora (harpin,,).Much less pronounced and more transient activation was detected in water-infiltrated leaves. Biochemical characteristics of the harpin,,-activated protein kinase (HAPK) activity are consistent with those of the mitogenactivated protein kinase family. HAPK is cytosolic and phosphorylates myelin basic protein on serine/threonine residues. Treatment with a protein tyrosine phosphatase completely eliminated HAPK activity, suggesting that tyrosine phosphorylation is required for posttranslational activation. Sustained HAPK activation after cycloheximide treatment implies that HAPK may be negatively regulated by a translation-dependent mechanism. The extracellular Ca2+ chelator ECTA or the protein kinase inhibitor K252a, infiltrated in planta together with harpinEa, partially blocked HAPK activation. The Ca2+-channel blocker La3+ had no effect on HAPK activation, suggesting that phosphorylation events precede and/or do not depend on the entry of extracellular CaZ+ into the cell. These results suggest that early signal transduction events during harpin,,-induced hypersensitive response elicitation depend in part on the activation of HAPK.

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“…In tobacco, the LeMPK3 ortholog WIPK had been shown to regulate wound-induced gene expression and JA synthesis (36,37). VIGS of MPK3 reduced transcript levels of MPK3 by 71% and did not alter transcript levels of MPK1 and MPK2 (Fig.…”

Section: Cosilencing Of Lempk1 and Lempk2mentioning

confidence: 99%

Tomato MAPKs LeMPK1, LeMPK2, and LeMPK3 function in the systemin-mediated defense response against herbivorous insects

Kandoth¹,

Ranf²,

Pancholi³

et al. 2007

Proc. Natl. Acad. Sci. U.S.A.

235

201

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Tobacco MAP Kinase: A Possible Mediator in Wound Signal Transduction Pathways

Cited by 510 publications

References 56 publications

Crystal structure of 12-oxophytodienoate reductase 3 from tomato: Self-inhibition by dimerization

Crystal structure of 12-oxophytodienoate reductase 3 from tomato: Self-inhibition by dimerization

Rapid and Transient Activation of a Myelin Basic Protein Kinase in Tobacco Leaves Treated with Harpin from Erwinia amylovora

Tomato MAPKs LeMPK1, LeMPK2, and LeMPK3 function in the systemin-mediated defense response against herbivorous insects

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