The ESCRT-III-like protein Vipp1 couples filament polymerization with membrane remodeling. It assembles planar sheets as well as 3D rings and helical polymers, all implicated in mitigating plastid-associated membrane stress. The architecture of Vipp1 planar sheets and helical polymers remains unknown, as do the geometric changes required to transition between polymeric forms. Here we show how cyanobacterial Vipp1 assembles into morphologically-related sheets and spirals on membranes in vitro. The spirals converge to form a central ring similar to those described in membrane budding. Cryo-EM structures of helical filaments reveal a close geometric relationship between Vipp1 helical and planar lattices. Moreover, the helical structures reveal how filaments twist—a process required for Vipp1, and likely other ESCRT-III filaments, to transition between planar and 3D architectures. Overall, our results provide a molecular model for Vipp1 ring biogenesis and a mechanism for Vipp1 membrane stabilization and repair, with implications for other ESCRT-III systems.

ESCRT-III 样蛋白 Vipp1 将细丝聚合与膜重塑相结合。它组装平面片材以及 3D 环和螺旋聚合物，所有这些都与减轻质体相关膜应力有关。Vipp1 平面片材和螺旋聚合物的结构仍然未知，在聚合物形式之间过渡所需的几何变化也仍然未知。在这里，我们展示了蓝藻 Vipp1 如何在体外组装成形态学相关的片状和螺旋状。螺旋会聚形成一个中心环，类似于膜出芽中描述的那些。螺旋丝的冷冻电镜结构揭示了 Vipp1 螺旋晶格和平面晶格之间的密切几何关系。此外，螺旋结构揭示了细丝如何扭曲——这是 Vipp1 以及可能的其他 ESCRT-III 细丝在平面和 3D 架构之间过渡所需的过程。总体而言，我们的结果为 Vipp1 环生物发生提供了分子模型，并为 Vipp1 膜稳定和修复提供了机制，对其他 ESCRT-III 系统具有影响。