Zhao Lei, Cheng Dongmei, Huang Xiahe, Chen Mei, Dall'Osto Luca, Xing Jiale, Gao Liyan, Li Lingyu, Wang Yale, Bassi Roberto, Peng Lianwei, Wang Yingchun, Rochaix Jean-David, Huang Fang
Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China.
University of the Chinese Academy of Sciences, Beijing 100049, China.
Plant Physiol. 2017 Aug;174(4):2419-2433. doi: 10.1104/pp.16.01465. Epub 2017 Jun 21.
Using a genetic approach, we have identified and characterized a novel protein, named Msf1 (Maintenance factor for photosystem I), that is required for the maintenance of specific components of the photosynthetic apparatus in the green alga Msf1 belongs to the superfamily of light-harvesting complex proteins with three transmembrane domains and consensus chlorophyll-binding sites. Loss of Msf1 leads to reduced accumulation of photosystem I and chlorophyll-binding proteins/complexes. Msf1is a component of a thylakoid complex containing key enzymes of the tetrapyrrole biosynthetic pathway, thus revealing a possible link between Msf1 and chlorophyll biosynthesis. Protein interaction assays and greening experiments demonstrate that Msf1 interacts with Copper target homolog1 (CHL27B) and accumulates concomitantly with chlorophyll in , implying that chlorophyll stabilizes Msf1. Contrary to other light-harvesting complex-like genes, the expression of is not stimulated by high-light stress, but its protein level increases significantly under heat shock, iron and copper limitation, as well as in stationary cells. Based on these results, we propose that Msf1 is required for the maintenance of photosystem I and specific protein-chlorophyll complexes especially under certain stress conditions.
通过遗传学方法，我们鉴定并表征了一种名为Msf1（光系统I维持因子）的新型蛋白质，它是绿藻光合装置特定组分维持所必需的。Msf1属于具有三个跨膜结构域和共有叶绿素结合位点的捕光复合体蛋白超家族。Msf1的缺失导致光系统I和叶绿素结合蛋白/复合体的积累减少。Msf1是类囊体复合体的一个组分，该复合体包含四吡咯生物合成途径的关键酶，从而揭示了Msf1与叶绿素生物合成之间的可能联系。蛋白质相互作用分析和绿化实验表明，Msf1与铜靶标同源物1（CHL27B）相互作用，并与叶绿素在 中同时积累，这意味着叶绿素使Msf1稳定。与其他捕光复合体样基因相反， 的表达不受高光胁迫刺激，但其蛋白质水平在热激、铁和铜限制以及静止细胞中显著增加。基于这些结果，我们提出Msf1是光系统I和特定蛋白质 - 叶绿素复合体维持所必需的，特别是在某些胁迫条件下。
