The concentration of Nuf, a Rab11 effector, at the microtubule-organizing center is cell cycle-regulated, dynein-dependent, and coincides with furrow formation
The concentration of Nuf, a Rab11 effector, at the microtubule-organizing center is cell cycle-regulated, dynein-dependent, and coincides with furrow formation
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DOI：
10.1091/mbc.e07-02-0146
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发表时间：
2007-09-01
影响因子：
3.3
通讯作者：
Sullivan, William
中科院分区：
文献类型：
--
作者：
Riggs, Blake;Fasulo, Barbara;Sullivan, William
动物胞质分裂依赖于膜的添加以及基于肌动球蛋白的收缩。回收内体 (RE) 衍生的囊泡是这种膜的关键来源。 Rab11 是一种与 RE 相关并参与囊泡靶向的小型 GTP 酶，是延长细胞因子沟槽所必需的。在早期果蝇胚胎中，核沉降物 (Nuf)（一种 Rab11 效应子）可促进囊泡介导的膜递送和内陷沟处的肌动蛋白组织。尽管 Rab11 在微管组织中心 (MTOC) 保持相对恒定的定位，但 Nuf 仅在发生沟内陷的细胞周期阶段才出现在 MTOC。我们证明 Nuf 蛋白水平在整个细胞周期中保持相对恒定，表明 Nuf 正在经历 MTOC 的浓缩和分散循环。 Nuf 和 Rab11 的 MTOC 正确定位需要微管，但不需要微丝。 Nuf 的 MTOC 本地化也依赖于 Dynein。免疫沉淀实验证明 Nuf 和 Dynein 存在物理相互作用。根据这些发现，并与以前的报告相反，我们证明微管是适当的中期沟形成所必需的。我们认为，细胞周期调节的、动力蛋白依赖性的 Nuf 向 MTOC 的募集会影响基于 RE 的囊泡递送至内陷沟的时间。
Animal cytokinesis relies on membrane addition as well as acto-myosin-based constriction. Recycling endosome (RE)-derived vesicles are a key source of this membrane. Rab11, a small GTPase associated with the RE and involved in vesicle targeting, is required for elongation of the cytokinetic furrow. In the early Drosophila embryo, Nuclear-fallout (Nuf), a Rab11 effector, promotes vesicle-mediated membrane delivery and actin organization at the invaginating furrow. Although Rab11 maintains a relatively constant localization at the microtubule-organizing center (MTOC), Nuf is present at the MTOC only during the phases of the cell cycle in which furrow invagination occurs. We demonstrate that Nuf protein levels remain relatively constant throughout the cell cycle, suggesting that Nuf is undergoing cycles of concentration and dispersion from the MTOC. Microtubules, but not microfilaments, are required for proper MTOC localization of Nuf and Rab11. The MTOC localization of Nuf also relies on Dynein. Immunoprecipitation experiments demonstrate that Nuf and Dynein physically interact. In accord with these findings, and in contrast to previous reports, we demonstrate that microtubules are required for proper metaphase furrow formation. We propose that the cell cycle-regulated, Dynein-dependent recruitment of Nuf to the MTOC influences the timing of RE-based vesicle delivery to the invaginating furrows.