信号转导
生物
细胞生物学
磷酸化
蛋白激酶A
蛋白质磷酸化
蛋白激酶C
拟南芥
茉莉酸
生物化学
基因
突变体
作者
Enrique Rojo,Elena Titarenko,José León,Susanne Berger,Guy Vancanneyt,José J. Sánchez‐Serrano
出处
期刊:Plant Journal
[Wiley]
日期:1998-01-01
卷期号:13 (2): 153-165
被引量:146
标识
DOI:10.1046/j.1365-313x.1998.00020.x
摘要
Summary Plants responses to mechanical injury are complex and include the induced expression of defence‐related genes. The phytohormone JA has been reported to mediate some of these responses. To elucidate further the signal transduction processes involved, the action of specific agonists and antagonists of known signalling effectors on the response of Arabidopsis thaliana plantlets to JA and wounding was investigated. The identification and characterization of a reversible protein phosphorylation step in a transduction pathway leading to JA‐induced gene transcription is reported. This phosphorylation event involved the opposing activities of a staurosporine‐sensitive protein kinase, negatively regulating the pathway, and a protein phosphatase, most probably of type 2 A, which activated JA‐responsive gene expression. JA activation via this pathway was blocked in the A. thaliana JA‐insensitive mutants jin1 , jin4 and coi1 , and by exogenous application of cycloheximide or auxins. Wound‐induced activation of JA‐responsive genes was also regulated by this protein phosphorylation step. An alternative wound signalling pathway, independent of JA, was also identified, leading to the transcriptional activation of a different set of genes. This JA‐independent pathway was also regulated by a protein phosphorylation switch, in which the protein kinase positively regulated the pathway while the protein phosphatase negatively regulated it. Moreover, a labile protein apparently repressed the expression of these genes. One of the genes analysed, JR3 , had a complex pattern of expression, possibly because it was regulated via both of the wound signalling pathways identified. According to the function of an homologous gene, JR3 may be involved in feedback inhibition of the JA response.
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