Mitosis-Coupled, Microtubule-Dependent Clustering of Endosomal Vesicles around Centrosomes
Mitosis-Coupled, Microtubule-Dependent Clustering of Endosomal Vesicles around Centrosomes
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DOI：
10.1247/csf.12028
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发表时间：
2013-01-01
影响因子：
1.5
通讯作者：
Nakayama, Kazuhisa
中科院分区：
文献类型：
--
作者：
Takatsu, Hiroyuki;Katoh, Yohei;Nakayama, Kazuhisa
在细胞分裂时，不仅细胞本身，而且它们的细胞器也发生了剧烈的形状变化，尽管对高尔基体以外的细胞器的行为仍然知之甚少。我们跟踪了转铁蛋白受体（TfnR）和其他蛋白质定位的时空变化。在早期有丝分裂阶段，一个人口的蛋白质循环通过内吞再循环室（ERC）表现出明显的时空变化，从高尔基体蛋白。在前期/前中期，当细胞的表面积与体积比达到最小值时，ERC蛋白以微管和动力蛋白依赖的方式瞬时组装在中心体周围，并很快分离成两个簇，伴随着重复的中心体的分离。电子显微镜分析显示，内吞转铁蛋白的内体囊泡簇紧围绕中心体，而不与彼此融合。随着胞质分裂的进行，细胞团逐渐瓦解，ERC蛋白重新聚集在犁沟赤道区周围。FRAP（荧光漂白后恢复）EGFP-TfnR表达细胞的分析显示，最小的膜内体簇和其他细胞室之间的交换，直到后期/末期，当膜交通恢复。我们的观察结果表明，ERC集群中心体发挥了重要作用，限制膜传递到质膜在有丝分裂早期阶段，当细胞的表面积与体积比达到最小值。
Upon cell division, not only cells themselves but also their organelles undergo drastic shape changes, although the behaviors of organelles other than the Golgi apparatus remain poorly understood. We followed the spatiotemporal changes in the localization of transferrin receptor (TfnR) and other proteins. In early mitotic phases, a population of proteins cycling through the endocytic recycling compartment (ERC) exhibits a distinct spatiotemporal change from that of Golgi proteins. In prophase/prometaphase, when the cell surface-to-volume ratio is reaching its minimum, the ERC proteins are transiently assembled around the centrated centrosome in a microtubule-and dynein-dependent manner, and soon separated polewards into two clusters concomitant with separation of duplicated centrosomes. Electron microscopic analysis revealed that endosomal vesicles containing endocytosed transferrin cluster tightly around centrosomes without fusing with one another. As cytokinesis proceeds, the clusters gradually collapse, and the ERC proteins reassemble around the furrowing equatorial region. FRAP (fluorescence recovery after photobleaching) analyses of EGFP-TfnR-expressing cells revealed minimal membrane exchange between the endosomal clusters and other cellular compartments until anaphase/telophase, when membrane traffic resumes. Our observations indicate that ERC clustering around centrosomes plays a fundamental role in restricting membrane delivery to the plasma membrane during early mitotic phases, when the cell surface-to-volume ratio reaches its minimum.