A Novel Katanin-Tethering Machinery Accelerates Cytokinesis
A Novel Katanin-Tethering Machinery Accelerates Cytokinesis
复制标题
DOI：
10.1016/j.cub.2019.09.049
复制
发表时间：
2019-12-02
期刊：
影响因子：
9.2
通讯作者：
Oda, Yoshihisa
中科院分区：
文献类型：
--
作者：
Sasaki, Takema;Tsutsumi, Motosuke;Oda, Yoshihisa
胞质分裂是细胞增殖的基础[1，2]。在植物中，双极短微管阵列形成成膜体，其介导囊泡运输到中间区，并引导将母细胞分离成两个子细胞的细胞壁的形成[2]。成膜体向细胞皮层离心扩张，引导皮层分裂部位的细胞板形成[3，4]。成膜体中间区的几种蛋白质促进微管的反平行集束和囊泡积累[5]。然而，短微管在成膜体发育过程中维持的机制，特别是微管在成膜体远端区的行为，知之甚少。在这里，我们表明，植物特异性蛋白质，皮质微管紊乱4（CORD 4），系留保守的微管切断蛋白katanin，以促进形成的短微管阵列在成膜体。CORD 4在有丝分裂过程中特异表达，定位于前期带和成膜体微管。定制的双光子旋转盘共聚焦显微镜显示，CORD 4迅速定位于微管在远端成膜体区成膜体组装后期，并坚持在整个成膜体扩张。CORD 4的缺失导致成膜体微管异常长且倾斜，成膜体扩张缓慢。p60 katanin亚基KTN 1以CORD 4依赖的方式定位于远端成膜体区。这些结果表明，CORD 4系KTN 1在成膜体调节微管长度，从而加速成膜体的生长。这揭示了存在一种独特的机制，通过调节katanin的作用来加速胞质分裂。
Cytokinesis is fundamental for cell proliferation [1, 2]. In plants, a bipolar short-microtubule array forms the phragmoplast, which mediates vesicle transport to the midzone and guides the formation of cell walls that separate the mother cell into two daughter cells [2]. The phragmoplast centrifugally expands toward the cell cortex to guide cell-plate formation at the cortical division site [3, 4]. Several proteins in the phragmoplast midzone facilitate the anti-parallel bundling of microtubules and vesicle accumulation [5]. However, the mechanisms by which short microtubules are maintained during phragmoplast development, in particular, the behavior of microtubules at the distal zone of phragmoplasts, are poorly understood. Here, we show that a plant-specific protein, CORTICAL MICROTUBULE DISORDERING 4 (CORD4), tethers the conserved microtubule-severing protein katanin to facilitate formation of the short-microtubule array in phragmoplasts. CORD4 was specifically expressed during mitosis and localized to preprophase bands and phragmoplast microtubules. Custom-made two-photon spinning disk confocal microscopy revealed that CORD4 rapidly localized to microtubules in the distal phragmoplast zone during phragmoplast assembly at late anaphase and persisted throughout phragmoplast expansion. Loss of CORD4 caused abnormally long and oblique phragmoplast microtubules and slow expansion of phragmoplasts. The p60 katanin subunit, KTN1, localized to the distal phragmoplast zone in a CORD4-dependent manner. These results suggest that CORD4 tethers KTN1 at phragmoplasts to modulate microtubule length, thereby accelerating phragmoplast growth. This reveals the presence of a distinct machinery to accelerate cytokinesis by regulating the action of katanin.