CROP: A Retromer- PROPPIN complex mediating membrane fission in the endo-lysosomal system

Endo-lysosomal compartments exchange proteins by fusing, fissioning, and through endosomal transport carriers. Thereby, they sort many plasma membrane receptors and transporters and control cellular signaling and metabolism. How the membrane fission events are catalyzed is poorly understood. Here, we identify the novel CROP complex as a factor acting at this step. CROP integrates PROPPIN Atg18 with a part of the endosome- and vacuole-associated retromer complex to generate a membrane fission device of much higher potency. We studied its activity in yeast, in human cells and on liposomes.

内体溶酶体区室（Endo-lysosomal compartments）通过膜融合、膜分裂以及内体转运载体完成蛋白质交换。借此，该类区室可分选众多质膜受体与转运蛋白，并调控细胞信号转导与细胞代谢。目前学界对膜分裂事件的催化机制仍知之甚少。本研究鉴定出新型CROP复合物（CROP complex）作为该步骤的作用因子。CROP复合物将PROPPIN蛋白Atg18（PROPPIN Atg18）与内体及液泡相关的Retromer复合物（retromer complex）的部分组分整合，进而构建出活性显著提升的膜分裂装置。我们分别在酵母、人类细胞以及脂质体（liposomes）体系中对该复合物的活性开展了研究。