Endosomal Sorting Complex Required for Transport (ESCRT) proteins can be transiently recruited to the plasma membrane for membrane repair and formation of extracellular vesicles. Here, we discovered micrometer-sized worm-shaped ESCRT structures that stably persist for multiple hours at the plasma membrane of macrophages, dendritic cells, and fibroblasts. These structures surround clusters of integrins and known cargoes of extracellular vesicles. The ESCRT structures are tightly connected to the cellular support and are left behind by the cells together with surrounding patches of membrane. The phospholipid composition is altered at the position of the ESCRT structures, and the actin cytoskeleton is locally degraded, which are hallmarks of membrane damage and extracellular vesicle formation. Disruption of actin polymerization increased the formation of the ESCRT structures and cell adhesion. The ESCRT structures were also present at plasma membrane contact sites with membrane-disrupting silica crystals. We propose that the ESCRT proteins are recruited to adhesion-induced membrane tears to induce extracellular shedding of the damaged membrane.

中文翻译：

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巨型蠕虫状 ESCRT 支架围绕肌动蛋白独立整合素簇

运输所需的内体分选复合物 (ESCRT) 蛋白可以短暂地募集到质膜上，用于膜修复和细胞外囊泡的形成。在这里，我们发现了微米大小的蠕虫状 ESCRT 结构，它们在巨噬细胞、树突细胞和成纤维细胞的质膜上稳定存在多个小时。这些结构围绕整联蛋白簇和已知的细胞外囊泡货物。ESCRT 结构与细胞支持物紧密相连，并与周围的膜片一起被细胞留下。ESCRT 结构位置的磷脂组成发生改变，肌动蛋白细胞骨架局部降解，这是膜损伤和细胞外囊泡形成的标志。肌动蛋白聚合的破坏增加了 ESCRT 结构的形成和细胞粘附。ESCRT 结构也存在于质膜与膜破坏二氧化硅晶体的接触位点。我们建议 ESCRT 蛋白被招募到粘附诱导的膜撕裂中，以诱导受损膜的细胞外脱落。