Cell Cycle-Dependent Microtubule-Based Dynamic Transport of Cytoplasmic Dynein in Mammalian Cells
Cell Cycle-Dependent Microtubule-Based Dynamic Transport of Cytoplasmic Dynein in Mammalian Cells
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DOI：
10.1371/journal.pone.0007827
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发表时间：
2009-11-13
期刊：
影响因子：
3.7
通讯作者：
Murayama, Takashi
中科院分区：
文献类型：
--
作者：
Kobayashi, Takuya;Murayama, Takashi
背景：细胞质动力蛋白复合体是一种多亚单位微管相关的大分子马达，参与细胞器定位、囊泡运输和细胞分裂等多种细胞功能。然而，动力蛋白在细胞周期中分布的调控机制尚未完全被了解。方法/主要发现：我们报道了通过表达多功能绿色荧光蛋白(MfGFP)标记的74 kDa中间链(IC74)，在HeLa细胞中进行细胞质动力蛋白的活细胞成像。IC74-mfGFP被成功地掺入到功能性动力蛋白复合体中。在间期，Dynein与MTS双向运动，MTS可能携带运输囊泡等货物。很大一部分动力蛋白与MT+末端跟踪蛋白(+TIPS)成员EB1一起向细胞外周移动，提示+TIPS介导了动力蛋白的转运。在间期晚期和前期，Dynein定位于中心体和放射状MT阵列。在早中期和中期，Dynein定位于纺锤体MTS，它经常从纺锤体极向染色体或细胞皮质移动。+TIPS可能参与纺锤体动力蛋白的运输。可能的动粒和皮质动力蛋白也被观察到。结论和意义：这些发现表明细胞质动力蛋白被运输到作用部位，为随后的细胞事件做准备，主要是通过基于MT的运输。在对有限浓度的蛋白质进行快速有效的转运方面，基于MT的转运可能比简单的可溶性动力蛋白扩散具有更大的优势。
Background: Cytoplasmic dynein complex is a large multi-subunit microtubule (MT)-associated molecular motor involved in various cellular functions including organelle positioning, vesicle transport and cell division. However, regulatory mechanism of the cell-cycle dependent distribution of dynein has not fully been understood.Methodology/Principal Findings: Here we report live-cell imaging of cytoplasmic dynein in HeLa cells, by expressing multifunctional green fluorescent protein (mfGFP)-tagged 74-kDa intermediate chain (IC74). IC74-mfGFP was successfully incorporated into functional dynein complex. In interphase, dynein moved bi-directionally along with MTs, which might carry cargos such as transport vesicles. A substantial fraction of dynein moved toward cell periphery together with EB1, a member of MT plus end-tracking proteins (+TIPs), suggesting +TIPs-mediated transport of dynein. In late-interphase and prophase, dynein was localized at the centrosomes and the radial MT array. In prometaphase and metaphase, dynein was localized at spindle MTs where it frequently moved from spindle poles toward chromosomes or cell cortex. +TIPs may be involved in the transport of spindle dyneins. Possible kinetochore and cortical dyneins were also observed.Conclusions and Significance: These findings suggest that cytoplasmic dynein is transported to the site of action in preparation for the following cellular events, primarily by the MT-based transport. The MT-based transport may have greater advantage than simple diffusion of soluble dynein in rapid and efficient transport of the limited concentration of the protein.