PTK, the chloroplast RNA polymerase-associated protein kinase from mustard (Sinapis alba), mediates redox control of plastid in vitro transcription
PTK, the chloroplast RNA polymerase-associated protein kinase from mustard (Sinapis alba), mediates redox control of plastid in vitro transcription
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DOI：
10.1023/a:1006177807844
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发表时间：
1999-03-01
影响因子：
5.1
通讯作者：
Link, G
中科院分区：
文献类型：
--
作者：
Baginsky, S;Tiller, K;Link, G
芥菜叶绿体RNA聚合酶是一种多亚基酶，由核心组分和相关因子组成。在后者中，由于其丝氨酸/苏氨酸型蛋白激酶活性而被称为PTK（质体转录激酶）的异源三聚体因子。PTK活性本身取决于其磷酸化状态。此外，我们表明，它响应谷胱甘肽，但不对其他氧化还原反应试剂进行了测试，谷胱甘肽和磷酸化作用拮抗。使用同源的体外系统，我们发现，PTK选择性磷酸化质体RNA聚合酶的亚基（S），并参与确定从叶绿体psbA启动子的忠实转录水平。总之，这些结果建立了磷酸化和氧化还原状态的质体基因表达的调节中的作用。
The major RNA polymerase from mustard chloroplasts is a multi-subunit enzyme consisting of core components and associated factors. Among the latter is a heterotrimeric factor named PTK (plastid transcription kinase) because of its serine/threonine-type protein kinase activity. PTK activity itself depends on its phosphorylation state. In addition, we show that it responds to glutathione but not to other redox-reactive reagents that were tested, and both glutathione and phosphorylation act antagonistically. Using a homologous in vitro system, we find that PTK selectively phosphorylates subunit(s) of plastid RNA polymerase and is involved in determining the level of faithful transcription from the chloroplast psbA promoter. Together, these results establish a role for phosphorylation and redox state in the regulation of plastid gene expression.