Spatiotemporal organization of thylakoid membrane biogenesis in cyanobacteria

大多数光合自养细菌含有一个复杂的细胞内膜系统，称为类囊体。这些内部结构代表能量转换膜，介导光合作用电子流和随后的ATP产生。越来越多的证据表明，这种生物能机械的生物起源和结构动力学是高度有序的空间和时间手段。我们最近的研究结果表明，在模式蓝藻集胞藻6803的光系统II（PSII）的生物合成是在类囊体融合形成会聚小管的区域启动。由于它们的突触样外观，它们偶尔会在称为“囊体”的部位接触质膜。这些生物膜子域的建立需要膜形成因子CurT和AncM。CurT在严重弯曲的相互连接的小管中积累到高水平，这些小管来自跨越整个细胞外围的生物膜网络。相反，AncM仅定位于管状系统的不同点，并标记囊点区域。因此，这两个作为真正的地标集胞藻6803类囊体膜生物发生的亚细胞组织。通过应用遗传，生物化学和各种微观方法的混合，该项目旨在阐明这些内部膜子域的工作模式在PSII生物发生的时空组织。基于CurT和AncM以及几个PSII相关的生源因素的识别，要解决的中心问题是：（一）是什么决定了生源区域的结构动力学？(ii)他们的确切职能组织是什么？

Most photoautotrophic bacteria contain a sophisticated intracellular membrane system named thylakoids. These internal structures represent energy transducing membranes that mediate photosynthetic electron flow and subsequent ATP generation. Accumulating evidence suggests that the biogenesis and structural dynamics of this bioenergetic machinery are highly ordered by both spatial and temporal means. Our recent findings indicate that photosystem II (PSII) biogenesis in the model cyanobacterium Synechocystis 6803 is initiated at regions where thylakoids fuse to form convergence tubules. These occasionally contact the plasma membrane at sites named “thylapses” due to their synapse-like appearance. The establishment of these biogenic membrane sub-domains requires the membrane-shaping factors CurT and AncM. CurT accumulates to high levels at heavily bended interconnected tubules which from a biogenic membrane network spanning the periphery of the entire cell. In contrast, AncM localizes only to distinct spots of the tubular system and marks thylapse regions. Thus, both serve as bona fide landmarks for the subcellular organization of thylakoid membrane biogenesis in Synechocystis 6803. By applying a blend of genetic, biochemical, and various microscopic methods this project aims at elucidating the working mode of these internal membrane sub-domains during the spatiotemporal organization of PSII biogenesis. Based on the identification of CurT and AncM as well as several PSII-related biogenesis factors, the central questions to be addressed are: (i) What determines the structural dynamics of biogenic regions? (ii) What is their precise functional organization?