Reversible Morphological Control of Tubulin-Encapsulating Giant Liposomes by Hydrostatic Pressure
Reversible Morphological Control of Tubulin-Encapsulating Giant Liposomes by Hydrostatic Pressure
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DOI：
10.1021/acs.langmuir.6b00799
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发表时间：
2016-04-19
期刊：
影响因子：
3.9
通讯作者：
Takiguchi, Kingo
中科院分区：
文献类型：
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作者：
Hayashi, Masahito;Nishiyama, Masayoshi;Takiguchi, Kingo
封装细胞骨架的脂质体最近引起了人们的广泛关注，以开发一种人造细胞样化学机械。然而，据我们所知，目前还没有关于含有细胞骨架的脂质体发生等温可逆形态变化的报道，因为细胞骨架的各个反应系统的状态需要一组不同的调节因子，即它们的相互作用蛋白来控制。在这里，我们重点关注流体静压来控制细胞大小的巨型脂质体（直径类似于 10 μm）内微管 (MT) 的聚合状态。 MT是由微管蛋白聚合形成的细胞骨架，由MT组成的细胞骨架系统非常动态，在活细胞中发挥许多重要作用，例如神经细胞的形态发生和有丝分裂期间纺锤体的形成。利用高压显微镜的实时成像，我们检查了静水压对微管蛋白封装的巨型脂质体形态的影响。在环境压力（0.1 MPa）下，许多脂质体由于其内部的微管蛋白聚合而形成突起。当施加高压（60MPa）时，突起在几十秒内收缩。这个过程被反复诱导（大约3次），压力释放后，突起在几分钟内再生。脂质体的这些变形率接近于迁移或变形活细胞的速度，而不是先前测量的单个MT的缩短和伸长率。这些结果表明，通过施加和释放静水压来调节巨型脂质体中MT的聚合状态，可以反复控制巨型脂质体突起的伸长和缩短。
Liposomes encapsulating cytoskeletons have drawn much recent attention to develop an artificial cell-like chemical-machinery; however, as far as we know, there has been no report showing isothermally reversible morphological changes of liposomes containing cytoskeletons because the sets of various regulatory factors, that is, their interacting proteins, are required to control the state of every reaction system of cytoskeletons. Here we focused on hydrostatic pressure to control the polymerization state of microtubules (MTs) within cell-sized giant liposomes (diameters similar to 10 mu m). MT is the cytoskeleton formed by the polymerization of tubulin, and cytoskeletal systems consisting of MTs are very dynamic and play many important roles in living cells, such as the morphogenesis of nerve cells and formation of the spindle apparatus during mitosis. Using real-time imaging with a high-pressure microscope, we examined the effects of hydrostatic pressure on the morphology of tubulin-encapsulating giant liposomes. At ambient pressure (0.1 MPa), many liposomes formed protrusions due to tubulin polymerization within them. When high pressure (60 MPa) was applied, the protrusions shrank within several tens of seconds. This process was repeatedly inducible (around three times), and after the pressure was released, the protrusions regenerated within several minutes. These deformation rates of the liposomes are close to the velocities of migrating or shape-changing living cells rather than the shortening and elongation rates of the single MTs, which have been previously measured. These results demonstrate that the elongation and shortening of protrusions of giant liposomes is repeatedly controllable by regulating the polymerization state of MTs within them by applying and releasing hydrostatic pressure.