Institut Jacques Monod, CNRS UMR7592 and Université Paris Diderot, 15 Rue Hélène Brion, 75205 Paris Cedex 13, France.
Institut Jacques Monod, CNRS UMR7592 and Université Paris Diderot, 15 Rue Hélène Brion, 75205 Paris Cedex 13, France; Image Analysis Hub, Institut Pasteur, 25-28 Rue du Dr Roux, 75015 Paris, France.
Curr Biol. 2018 Oct 22;28(20):3342-3351.e3. doi: 10.1016/j.cub.2018.09.022. Epub 2018 Oct 11.
Polar cell growth is a conserved morphogenetic process needed for survival, mating, and infection [1, 2]. It typically implicates the assembly and spatial stabilization of a cortical polar domain of the active form of a small GTPase of the Rho family, such as Cdc42, which promotes cytoskeleton assembly and secretion needed for local surface expansion [3-6]. In multiple physiological instances, polarity domains may switch from being spatially unstable, exhibiting a wandering behavior around the cell surface, to being stable at a fixed cellular location [7-11]. Here, we show that the rate of surface growth may be a key determinant in controlling the spatial stability of active Cdc42 domains. Reducing the growth rate of single rod-shaped fission yeast cells using chemical, genetic, and mechanical means systematically causes polar domains to detach from cell tips and oscillate around the cell surface within minutes. Conversely, an abrupt increase in growth rate improves domain stabilization. A candidate screen identifies vesicular transport along actin cables as an important module mediating this process. Similar behavior observed in distant filamentous fungi suggests that this positive feedback between growth and polarity could represent a basal property of eukaryotic polarization, promoting persistent polar growth as well as growth redirection with respect to the mechanical environment of cells.
极地细胞生长是一种保守的形态发生过程，对于生存、交配和感染都是必需的[1,2]。它通常涉及到 Rho 家族小 GTP 酶的活性形式的皮质极性域的组装和空间稳定，例如 Cdc42，这促进了细胞骨架组装和分泌，是局部表面扩展所必需的[3-6]。在多种生理情况下，极性域可能从空间不稳定（表现为在细胞表面周围的漫游行为）转变为在固定的细胞位置稳定[7-11]。在这里，我们表明表面生长速率可能是控制活性 Cdc42 域空间稳定性的关键决定因素。使用化学、遗传和机械手段降低单个杆状裂殖酵母细胞的生长速率会导致极性域在数分钟内从细胞尖端脱离并在细胞表面周围振荡。相反，生长速率的突然增加会改善域稳定性。候选物筛选鉴定出沿肌动蛋白电缆的囊泡运输是介导该过程的重要模块。在遥远的丝状真菌中观察到的类似行为表明，这种生长和极性之间的正反馈可能代表真核细胞极化的基本特性，促进持久的极性生长以及相对于细胞的机械环境的生长方向改变。
