Nanoscale bending of plasma membrane increases cell adhesion, induces cell-signalling, triggers F-actin assembly and endocytosis in tissue-cultured cells. The underlying mechanisms are not very well understood. Here, we show that stretching the plasma membrane of somatic cyst cell around rigid spermatid heads generates a stable, tubular endomembrane scaffold supported by contractile actomyosin. The structure resembles an actin-basket covering the bundle of spermatid heads. Genetic analysis suggests that the actomyosin organisation is nucleated exclusively by the Formins, Diaphanous and DAAM, downstream of Rho1, recruited by the Bin-Amphyphysin-Rvs (BAR)-domain protein, Amphiphysin, around the spermatid heads. Actomyosin activity at the actin-basket gathers the spermatid heads into a compact bundle and resists the invasion of the somatic cell by the intruding spermatids. These observations reveal a new response mechanism of nanoscale bending of the plasma membrane, which generates a novel cell adhesion strategy through active clamping.

中文翻译：

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质膜的纳米压痕通过选择性激活Amphiphysin-Rho1-Dia / DAAM和Rok途径建立收缩性肌动球蛋白支架。

质膜的纳米级弯曲会增加细胞粘附，诱导细胞信号传导，触发F-肌动蛋白组装和组织培养细胞的内吞作用。潜在的机制不是很了解。在这里，我们表明，在刚性精子细胞头周围拉伸体细胞囊细胞的质膜会产生稳定的，由收缩性肌动球蛋白支持的管状内膜支架。该结构类似于肌动蛋白篮，覆盖精子束。遗传分析表明，放线菌素组织仅由Rho1下游的Formins，Diaphanous和DAAM形成核，由Bin-Amphyphysin-Rvs（BAR）域蛋白Amphiphysin募集，位于精子的头部周围。肌动蛋白篮上的肌动球蛋白活性将精子的头部聚集成一个紧密的束，并抵抗入侵的精子对体细胞的入侵。这些观察结果揭示了质膜纳米级弯曲的新反应机制，该机制通过主动钳制产生了新的细胞粘附策略。