Structural basis for VIPP1 oligomerization and maintenance of thylakoid membrane integrity
Structural basis for VIPP1 oligomerization and maintenance of thylakoid membrane integrity
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DOI：
10.1016/j.cell.2021.05.011
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发表时间：
2021-07-08
期刊：
影响因子：
64.5
通讯作者：
Engel, Benjamin D.
中科院分区：
文献类型：
--
作者：
Gupta, Tilak Kumar;Klumpe, Sven;Engel, Benjamin D.
质体中囊泡诱导蛋白1 （VIPP1）对类囊体膜的生物发生和维持至关重要，类囊体膜将光转化为生命。然而，目前尚不清楚VIPP1如何发挥其重要的膜重塑功能。在这里，我们使用低温电子显微镜来确定蓝藻VIPP1环的结构，揭示VIPP1单体如何弯曲和交织形成不同对称的篮状组件。三个VIPP1单体在环的一端协调一个非规范核苷酸结合袋。在环的腔内，来自每个单体的两亲螺旋排列形成大型疏水柱，使VIPP1能够结合并弯曲膜。这些疏水表面的体内突变在强光下引起极端的类囊体肿胀，表明VIPP1脂质结合在抵抗应力诱导的损伤中起重要作用。利用低温相关光学和电子显微镜（cro - clem），我们观察到衣藻叶绿体中包裹膜管的低聚VIPP1外壳。我们的工作为理解VIPP1如何指导类囊体的生物发生和维持提供了结构基础。
Vesicle-inducing protein in plastids 1 (VIPP1) is essential for the biogenesis and maintenance of thylakoid membranes, which transform light into life. However, it is unknown how VIPP1 performs its vital membrane-remodeling functions. Here, we use cryo-electron microscopy to determine structures of cyanobacterial VIPP1 rings, revealing how VIPP1 monomers flex and interweave to form basket-like assemblies of different symmetries. Three VIPP1 monomers together coordinate a non-canonical nucleotide binding pocket on one end of the ring. Inside the ring's lumen, amphipathic helices from each monomer align to form large hydrophobic columns, enabling VIPP1 to bind and curve membranes. In vivo mutations in these hydrophobic surfaces cause extreme thylakoid swelling under high light, indicating an essential role of VIPP1 lipid binding in resisting stress-induced damage. Using cryo-correlative light and electron microscopy (cryo-CLEM), we observe oligomeric VIPP1 coats encapsulating membrane tubules within the Chlamydomonas chloroplast. Our work provides a structural foundation for understanding how VIPP1 directs thylakoid biogenesis and maintenance.