Laboratory of Cell Physics ISIS/IGBMC, ISIS &icFRC, Université de Strasbourg &CNRS, 8 allée Gaspard Monge, Strasbourg 67000, France.
Institut de Génétique et de Biologie Moléculaire et Cellulaire, Illkirch, France.
Nat Commun. 2016 Jul 1;7:11860. doi: 10.1038/ncomms11860.
The cytokinetic ring is essential for separating daughter cells during division. It consists of actin filaments and myosin motors that are generally assumed to organize as sarcomeres similar to skeletal muscles. However, direct evidence is lacking. Here we show that the internal organization and dynamics of rings are different from sarcomeres and distinct in different cell types. Using micro-cavities to orient rings in single focal planes, we find in mammalian cells a transition from a homogeneous distribution to a periodic pattern of myosin clusters at the onset of constriction. In contrast, in fission yeast, myosin clusters rotate prior to and during constriction. Theoretical analysis indicates that both patterns result from acto-myosin self-organization and reveals differences in the respective stresses. These findings suggest distinct functional roles for rings: contraction in mammalian cells and transport in fission yeast. Thus self-organization under different conditions may be a generic feature for regulating morphogenesis in vivo.
有丝分裂环对于细胞分裂时分离子细胞至关重要。它由肌动蛋白丝和肌球蛋白马达组成，通常被认为类似于骨骼肌那样组织成肌节。然而，直接证据却缺乏。在这里，我们表明，环的内部组织和动力学与肌节不同，并且在不同的细胞类型中也不同。我们使用微腔将环定向在单个焦平面上，在哺乳动物细胞中，我们发现肌球蛋白簇在收缩开始时从均匀分布转变为周期性模式。相比之下，在裂殖酵母中，肌球蛋白簇在收缩前和收缩期间旋转。理论分析表明，这两种模式都是由肌动球蛋白的自组织产生的，并揭示了各自的力的差异。这些发现表明环具有不同的功能作用：在哺乳动物细胞中是收缩，而在裂殖酵母中是运输。因此，在不同条件下的自组织可能是调节体内形态发生的普遍特征。
