Nédélec F J, Surrey T, Maggs A C, Leibler S
Department of Molecular Biology, Princeton University, New Jersey 08544, USA.
Nature. 1997 Sep 18;389(6648):305-8. doi: 10.1038/38532.
Cellular structures are established and maintained through a dynamic interplay between assembly and regulatory processes. Self-organization of molecular components provides a variety of possible spatial structures: the regulatory machinery chooses the most appropriate to express a given cellular function. Here we study the extent and the characteristics of self-organization using microtubules and molecular motors as a model system. These components are known to participate in the formation of many cellular structures, such as the dynamic asters found in mitotic and meiotic spindles. Purified motors and microtubules have previously been observed to form asters in vitro. We have reproduced this result with a simple system consisting solely of multi-headed constructs of the motor protein kinesin and stabilized microtubules. We show that dynamic asters can also be obtained from a homogeneous solution of tubulin and motors. By varying the relative concentrations of the components, we obtain a variety of self-organized structures. Further, by studying this process in a constrained geometry of micro-fabricated glass chambers, we demonstrate that the same final structure can be reached through different assembly 'pathways.
细胞结构是通过组装和调控过程之间的动态相互作用建立和维持的。分子成分的自组织提供了多种可能的空间结构：调控机制选择最合适的结构来表达特定的细胞功能。在这里，我们以微管和分子马达为模型系统，研究自组织的程度和特征。已知这些成分参与许多细胞结构的形成，如在有丝分裂和减数分裂纺锤体中发现的动态星状体。以前观察到纯化的马达和微管在体外形成星状体。我们用一个仅由马达蛋白驱动蛋白的多头构建体和稳定的微管组成的简单系统重现了这一结果。我们表明，动态星状体也可以从微管蛋白和马达的均匀溶液中获得。通过改变成分的相对浓度，我们获得了各种自组织结构。此外，通过在微制造玻璃室的受限几何结构中研究这一过程，我们证明相同的最终结构可以通过不同的组装“途径”实现。
