Photosystem II core phosphorylation and photosynthetic acclimation require two different protein kinases
Photosystem II core phosphorylation and photosynthetic acclimation require two different protein kinases
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DOI：
10.1038/nature04016
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发表时间：
2005-10-20
期刊：
影响因子：
64.8
通讯作者：
Leister, D
中科院分区：
文献类型：
--
作者：
Bonardi, V;Pesaresi, P;Leister, D
光照变化引起类囊体蛋白的修饰和光合机制的重组。在短期内，这涉及光系统II（PSII）和捕光（LHCII）蛋白的磷酸化。PSII磷酸化被认为与PSII周转有关（1，2），而LHCII磷酸化与LHCII的重新定位和激发能（状态转换）在光系统之间的重新分配有关（3，4）。从长远来看，光系统之间能量分配的不平衡可以通过调节光系统化学计量来抵消（5，6）。在绿色衣原体和拟南芥中，状态转换分别需要邻苯二甲酸酯蛋白激酶STT 7和STN 7（7，8）。在这里，我们表明，在拟南芥中的第二个蛋白激酶，STN8，是所需的PSII核心蛋白的定量磷酸化。然而，在高强度光下的PSII活性的影响只有轻微的stn8突变体，和D1营业额是从野生型无法区分，这意味着可逆的蛋白磷酸化是不是必不可少的PSII修复。适应光质量的变化是有缺陷的stn7，但不是在stn8突变体，表明短期和长期的光合适应耦合。因此，LHCII或STN7的未知底物的磷酸化对于光合基因表达的控制也是至关重要的。
Illumination changes elicit modifications of thylakoid proteins and reorganization of the photosynthetic machinery. This involves, in the short term, phosphorylation of photosystem II (PSII) and light-harvesting (LHCII) proteins. PSII phosphorylation is thought to be relevant for PSII turnover(1,2), whereas LHCII phosphorylation is associated with the relocation of LHCII and the redistribution of excitation energy (state transitions) between photosystems(3,4). In the long term, imbalances in energy distribution between photosystems are counteracted by adjusting photosystem stoichiometry(5,6). In the green alga Chlamydomonas and the plant Arabidopsis, state transitions require the orthologous protein kinases STT7 and STN7, respectively(7,8). Here we show that in Arabidopsis a second protein kinase, STN8, is required for the quantitative phosphorylation of PSII core proteins. However, PSII activity under high-intensity light is affected only slightly in stn8 mutants, and D1 turnover is indistinguishable from the wild type, implying that reversible protein phosphorylation is not essential for PSII repair. Acclimation to changes in light quality is defective in stn7 but not in stn8 mutants, indicating that short-term and long-term photosynthetic adaptations are coupled. Therefore the phosphorylation of LHCII, or of an unknown substrate of STN7, is also crucial for the control of photosynthetic gene expression.