Vesicle-inducing protein in plastids 1 (Vipp1) is critical for thylakoid membrane biogenesis and maintenance. Although Vipp1 has recently been identified as a member of the endosomal sorting complexes required for transport III superfamily, it is still unknown how Vipp1 remodels membranes. Here, we present cryo-electron microscopy structures of Synechocystis Vipp1 interacting with membranes: seven structures of helical and stacked-ring assemblies at 5–7-Å resolution engulfing membranes and three carpet structures covering lipid vesicles at ~20-Å resolution using subtomogram averaging. By analyzing ten structures of N-terminally truncated Vipp1, we show that helix α0 is essential for membrane tubulation and forms the membrane-anchoring domain of Vipp1. Lastly, using a conformation-restrained Vipp1 mutant, we reduced the structural plasticity of Vipp1 and determined two structures of Vipp1 at 3.0-Å resolution, resolving the molecular details of membrane-anchoring and intersubunit contacts of helix α0. Our data reveal membrane curvature-dependent structural transitions from carpets to rings and rods, some of which are capable of inducing and/or stabilizing high local membrane curvature triggering membrane fusion.

质体 1 （Vipp1） 中的囊泡诱导蛋白对于类囊体膜的生物发生和维持至关重要。尽管 Vipp1 最近已被确定为转运 III 超家族所需的内体分选复合物的成员，但 Vipp1 如何重塑膜仍未知。在这里，我们展示了集胞藻 Vipp1 与膜相互作用的冷冻电子显微镜结构：7 种螺旋和堆叠环组件结构，分辨率为 5-7-Å 吞没膜，以及三种地毯结构，以 ~20-Å 分辨率覆盖脂质囊泡，使用亚断层照片平均。通过分析 N 末端截短的 Vipp1 的 10 个结构，我们表明螺旋 α0 对膜管形成至关重要，并形成 Vipp1 的膜锚定结构域。最后，使用构象抑制的 Vipp1 突变体，我们降低了 Vipp1 的结构可塑性，并以 3.0-Å 分辨率确定了 Vipp1 的两个结构，解析了膜锚定和螺旋 α0 亚基间接触的分子细节。我们的数据揭示了从地毯到环和棒的膜曲率依赖性结构转变，其中一些能够诱导和/或稳定高局部膜曲率触发膜融合。