Myosin XI-i Links the Nuclear Membrane to the Cytoskeleton to Control Nuclear Movement and Shape in Arabidopsis
Myosin XI-i Links the Nuclear Membrane to the Cytoskeleton to Control Nuclear Movement and Shape in Arabidopsis
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DOI：
10.1016/j.cub.2013.07.035
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发表时间：
2013-09-23
期刊：
影响因子：
9.2
通讯作者：
Hara-Nishimura, Ikuko
中科院分区：
文献类型：
--
作者：
Tamura, Kentaro;Iwabuchi, Kosei;Hara-Nishimura, Ikuko
细胞核通过核质连接体与细胞质沟通，核质连接体维持细胞核的形状并介导其迁移。与动物细胞核不同，动物细胞核由运动蛋白（驱动蛋白和动力蛋白）沿着微管细胞骨架移动[1，2]，植物细胞核沿着肌动蛋白丝细胞骨架快速移动并沿着移动更远[3]。这意味着，植物使用一个独特的核质连接器的核动力学，虽然它的分子身份是未知的。在这里，我们描述了一种新型的核质连接肌球蛋白马达和核膜蛋白组成。在拟南芥突变体kaku 1中，核运动受损，核膜异常内陷。负责基因被确定为肌球蛋白XI-i，其编码植物特异性肌球蛋白。肌球蛋白XI-i特异性定位于核膜上，在核膜上与外核膜蛋白WIT 1和WIT 2发生物理相互作用。两种WIT蛋白都是将肌球蛋白XI-1锚定到核膜和核运动所需的。植物细胞的一个显著特征是暗诱导的叶肉细胞核定位。肌球蛋白XI-1或WIT蛋白的缺乏减少了暗诱导的核定位。植物独特的核质连锁可能使核快速定位响应环境刺激。
The cell nucleus communicates with the cytoplasm through a nucleocytoplasmic linker that maintains the shape of the nucleus and mediates its migration. In contrast to animal nuclei, which are moved by motor proteins (kinesins and dyneins) along the microtubule cytoskeleton [1, 2], plant nuclei move rapidly and farther along an actin filament cytoskeleton [3]. This implies that plants use a distinct nucleocytoplasmic linker for nuclear dynamics, although its molecular identity is unknown. Here, we describe a new type of nucleocytoplasmic linker consisting of a myosin motor and nuclear membrane proteins. In the Arabidopsis thaliana mutant kaku1, nuclear movement was impaired and the nuclear envelope was abnormally invaginated. The responsible gene was identified as myosin XI-i, which encodes a plant-specific myosin. Myosin XI-i is specifically localized on the nuclear membrane, where it physically interacts with the outer-nuclear-membrane proteins WIT1 and WIT2. Both WIT proteins are required for anchoring myosin XI-i to the nuclear membrane and for nuclear movement. A striking feature of plant cells is dark-induced nuclear positioning in mesophyll cells. A deficiency of either myosin XI-i or WIT proteins diminished dark-induced nuclear positioning. The unique nucleocytoplasmic linkage in plants might enable rapid nuclear positioning in response to environmental stimuli.