Peters Christopher, Baars Tonie L, Bühler Susanne, Mayer Andreas
Département de Biochimie, Université de Lausanne, Chemin des Boveresses 155, 1066 Epalinges, Switzerland.
Cell. 2004 Nov 24;119(5):667-78. doi: 10.1016/j.cell.2004.11.023.
Membrane fusion and fission are antagonistic reactions controlled by different proteins. Dynamins promote membrane fission by GTP-driven changes of conformation and polymerization state, while SNAREs fuse membranes by forming complexes between t- and v-SNAREs from apposed vesicles. Here, we describe a role of the dynamin-like GTPase Vps1p in fusion of yeast vacuoles. Vps1p forms polymers that couple several t-SNAREs together. At the onset of fusion, the SNARE-activating ATPase Sec18p/NSF and the t-SNARE depolymerize Vps1p and release it from the membrane. This activity is independent of the SNARE coactivator Sec17p/alpha-SNAP and of the v-SNARE. Vps1p release liberates the t-SNAREs for initiating fusion and at the same time disrupts fission activity. We propose that reciprocal control between fusion and fission components exists, which may prevent futile cycles of fission and fusion.
膜融合和裂变是由不同蛋白质控制的拮抗反应。发动蛋白通过GTP驱动的构象和聚合状态变化促进膜裂变，而SNARE蛋白则通过在来自相对囊泡的t-SNARE和v-SNARE之间形成复合物来融合膜。在这里，我们描述了动力蛋白样GTP酶Vps1p在酵母液泡融合中的作用。Vps1p形成聚合物，将几种t-SNARE蛋白连接在一起。在融合开始时，SNARE激活ATP酶Sec18p/NSF和t-SNARE使Vps1p解聚并将其从膜上释放。这种活性独立于SNARE共激活因子Sec17p/α-SNAP和v-SNARE。Vps1p的释放使t-SNARE得以启动融合，同时破坏裂变活性。我们提出，融合和裂变成分之间存在相互控制，这可能会阻止无用的裂变和融合循环。
