Daga Rafael R, Lee Kyeng-Gea, Bratman Scott, Salas-Pino Silvia, Chang Fred
Microbiology Department, Columbia University College of Physicians and Surgeons, 701 168th St., New York, NY 10032, USA.
Nat Cell Biol. 2006 Oct;8(10):1108-13. doi: 10.1038/ncb1480. Epub 2006 Sep 24.
Self-organization of cellular structures is an emerging principle underlying cellular architecture. Properties of dynamic microtubules and microtubule-binding proteins contribute to the self-assembly of structures such as microtubule asters. In the fission yeast Schizosaccharomyces pombe, longitudinal arrays of cytoplasmic microtubule bundles regulate cell polarity and nuclear positioning. These bundles are thought to be organized from the nucleus at multiple interphase microtubule organizing centres (iMTOCs). Here, we find that microtubule bundles assemble even in cells that lack a nucleus. These bundles have normal organization, dynamics and orientation, and exhibit anti-parallel overlaps in the middle of the cell. The mechanisms that are responsible for formation of these microtubule bundles include cytoplasmic microtubule nucleation, microtubule release from the equatorial MTOC (eMTOC), and the dynamic fusion and splitting of microtubule bundles. Bundle formation and organization are dependent on mto1p (gamma-TUC associated protein), ase1p (PRC1), klp2p (kinesin-14) and tip1p (CLIP-170). Positioning of nuclear fragments and polarity factors by these microtubules illustrates how self-organization of these bundles contributes to establishing global spatial order.
细胞结构的自组织是细胞架构背后一个正在兴起的原理。动态微管和微管结合蛋白的特性有助于微管星状体等结构的自组装。在裂殖酵母粟酒裂殖酵母中，细胞质微管束的纵向阵列调节细胞极性和细胞核定位。这些微管束被认为是在多个间期微管组织中心（iMTOC）由细胞核组织形成的。在这里，我们发现即使在没有细胞核的细胞中微管束也能组装。这些微管束具有正常的组织、动态变化和方向，并在细胞中部呈现反平行重叠。负责这些微管束形成的机制包括细胞质微管成核、微管从赤道微管组织中心（eMTOC）释放，以及微管束的动态融合和分裂。微管束的形成和组织依赖于mto1p（γ-TUC相关蛋白）、ase1p（PRC1）、klp2p（驱动蛋白-14）和tip1p（CLIP-170）。这些微管对核片段和极性因子的定位说明了这些微管束的自组织是如何有助于建立全局空间秩序的。
