LBCMCP, Centre de Biologie Intégrative (CBI), Université de Toulouse, CNRS, UPS, 31062, Toulouse, France.
Université Côte d'Azur, CNRS, Inserm, iBV, Nice, France.
Nat Commun. 2020 Apr 21;11(1):1921. doi: 10.1038/s41467-020-15593-2.
Actomyosin supracellular networks emerge during development and tissue repair. These cytoskeletal structures are able to generate large scale forces that can extensively remodel epithelia driving tissue buckling, closure and extension. How supracellular networks emerge, are controlled and mechanically work still remain elusive. During Drosophila oogenesis, the egg chamber elongates along the anterior-posterior axis. Here we show that a dorsal-ventral polarized supracellular F-actin network, running around the egg chamber on the basal side of follicle cells, emerges from polarized intercellular filopodia that radiate from basal stress fibers and extend penetrating neighboring cell cortexes. Filopodia can be mechanosensitive and function as cell-cell anchoring sites. The small GTPase Cdc42 governs the formation and distribution of intercellular filopodia and stress fibers in follicle cells. Finally, our study shows that a Cdc42-dependent supracellular cytoskeletal network provides a scaffold integrating local oscillatory actomyosin contractions at the tissue scale to drive global polarized forces and tissue elongation.
细胞骨架超网络在发育和组织修复过程中出现。这些细胞骨架结构能够产生大范围的力，从而广泛重塑上皮组织，推动组织弯曲、闭合和延伸。超网络是如何出现的、如何被控制以及如何发挥机械作用仍然难以捉摸。在果蝇卵子发生过程中，卵室沿着前后轴伸长。在这里，我们发现一个背-腹极化的 F-actin 超网络，沿着滤泡细胞底部围绕卵室运行，它是由从基底应力纤维辐射出来并延伸穿透邻近细胞皮层的极化细胞间丝状伪足形成的。丝状伪足可以是机械敏感的，并作为细胞-细胞锚定点发挥作用。小分子 GTPase Cdc42 调控滤泡细胞中细胞间丝状伪足和应力纤维的形成和分布。最后，我们的研究表明，一个依赖于 Cdc42 的细胞骨架超网络提供了一个支架，将组织尺度上局部的振荡肌动球蛋白收缩整合在一起，以驱动全局极化力和组织伸长。
