Department of Botany, The University of British Columbia, Vancouver, British Columbia, V6T 1Z4 Canada.
Nat Commun. 2011 Aug 16;2:430. doi: 10.1038/ncomms1444.
It is well known that the parallel order of microtubules in the plant cell cortex defines the direction of cell expansion, yet it remains unclear how microtubule orientation is controlled, especially on a cell-wide basis. Here we show through 4D imaging and computational modelling that plant cell polyhedral geometry provides spatial input that determines array orientation and heterogeneity. Microtubules depolymerize when encountering sharp cell edges head-on, whereas those oriented parallel to those sharp edges remain. Edge-induced microtubule depolymerization, however, is overcome by the microtubule-associated protein CLASP, which accumulates at specific cell edges, enables microtubule growth around sharp edges and promotes formation of microtubule bundles that span adjacent cell faces. By computationally modelling dynamic 'microtubules on a cube' with edges differentially permissive to microtubule passage, we show that the CLASP-edge complex is a 'tuneable' microtubule organizer, with the inherent flexibility to generate the numerous cortical array patterns observed in nature.
众所周知，植物细胞皮层中微管的平行排列决定了细胞扩张的方向，但微管的定向如何被控制，特别是在全细胞的基础上，目前仍不清楚。在这里，我们通过 4D 成像和计算建模表明，植物细胞多面体几何形状提供了空间输入，决定了阵列的方向和异质性。当微管迎头遇到尖锐的细胞边缘时会解聚，而那些与这些尖锐边缘平行的微管则保持不变。然而，边缘诱导的微管解聚被微管相关蛋白 CLASP 克服，CLASP 在特定的细胞边缘积累，使微管能够在尖锐边缘周围生长，并促进微管束的形成，这些微管束跨越相邻的细胞面。通过对具有不同微管通过性边缘的动态“立方上的微管”进行计算建模，我们表明 CLASP-边缘复合物是一个“可调”的微管组织者，具有内在的灵活性，可以产生自然界中观察到的众多皮层阵列模式。
