Thylakoid Membrane Architecture in Synechocystis Depends on CurT, a Homolog of the Granal CURVATURE THYLAKOID1 Proteins
Thylakoid Membrane Architecture in Synechocystis Depends on CurT, a Homolog of the Granal CURVATURE THYLAKOID1 Proteins
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DOI：
10.1105/tpc.16.00491
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发表时间：
2016-09-01
期刊：
影响因子：
11.6
通讯作者：
Nickelsen, Joerg
中科院分区：
文献类型：
--
作者：
Heinz, Steffen;Rast, Anna;Nickelsen, Joerg
光合作用发生在类囊体（一种高度专门化的膜系统）中。在蓝细菌集胞藻属PCC 6803（以下简称集胞藻属6803）中，类囊体平行于质膜排列，偶尔会向质膜会聚，形成生物发生中心。PSII组装的初始步骤被认为发生在这些区域中，这些区域包含具有早期组装因子PratA的膜亚室，并被称为PratA定义的膜（PDM）。CurT是集胞藻属6803的同源物，与拟南芥属CURVATURE THYLAKOID 1家族的基粒形成蛋白同源，CurT的缺失导致类囊体组织的破坏和生物发生中心的缺失。因此，PSII的组装效率较低，积累仅为野生型水平的50%。CurT在体外诱导膜弯曲，并分布在整个类囊体，在生物发生中心的局部浓度。活细胞成像显示，它在细胞外围形成一个复杂的管状网络。CurT是几种高分子量复合物的一部分，Blue Native/SDS-PAGE和等电聚焦表明不同的同种型与PDM和类囊体相关。此外，CurT缺陷增强了对渗透胁迫的敏感性，增加了CurT功能的复杂性。我们建议，CurT是至关重要的膜结构的分化，包括PSII相关的生物发生中心的形成，在集胞藻6803。
Photosynthesis occurs in thylakoids, a highly specialized membrane system. In the cyanobacterium Synechocystis sp PCC 6803 (hereafter Synechocystis 6803), the thylakoids are arranged parallel to the plasma membrane and occasionally converge toward it to form biogenesis centers. The initial steps in PSII assembly are thought to take place in these regions, which contain a membrane subcompartment harboring the early assembly factor PratA and are referred to as PratA-defined membranes (PDMs). Loss of CurT, the Synechocystis 6803 homolog of Arabidopsis thaliana grana-shaping proteins of the CURVATURE THYLAKOID1 family, results in disrupted thylakoid organization and the absence of biogenesis centers. As a consequence, PSII is less efficiently assembled and accumulates to only 50% of wild-type levels. CurT induces membrane curvature in vitro and is distributed all over the thylakoids, with local concentrations at biogenesis centers. There it forms a sophisticated tubular network at the cell periphery, as revealed by live-cell imaging. CurT is part of several high molecular mass complexes, and Blue Native/SDS-PAGE and isoelectric focusing demonstrated that different isoforms associate with PDMs and thylakoids. Moreover, CurT deficiency enhances sensitivity to osmotic stress, adding a level of complexity to CurT function. We propose that CurT is crucial for the differentiation of membrane architecture, including the formation of PSII-related biogenesis centers, in Synechocystis 6803.