Riggs Blake, Rothwell Wendy, Mische Sarah, Hickson Gilles R X, Matheson Johanne, Hays Thomas S, Gould Gwyn W, Sullivan William
Deptartment of Molecular, Cellular, and Developmental Biology, University of California, Santa Cruz, Santa Cruz, CA 95064, USA.
J Cell Biol. 2003 Oct 13;163(1):143-54. doi: 10.1083/jcb.200305115. Epub 2003 Oct 6.
Cytokinesis requires a dramatic remodeling of the cortical cytoskeleton as well as membrane addition. The Drosophila pericentrosomal protein, Nuclear-fallout (Nuf), provides a link between these two processes. In nuf-derived embryos, actin remodeling and membrane recruitment during the initial stages of metaphase and cellular furrow formation are disrupted. Nuf is a homologue of arfophilin-2, an ADP ribosylation factor effector that binds Rab11 and influences recycling endosome (RE) organization. Here, we show that Nuf is an important component of the RE, and that these phenotypes are a consequence of Nuf activities at the RE. Nuf exhibits extensive colocalization with Rab11, a key RE component. GST pull-downs and the presence of a conserved Rab11-binding domain in Nuf demonstrate that Nuf and Rab11 physically associate. In addition, Nuf and Rab11 are mutually required for their localization to the RE. Embryos with reduced levels of Rab11 produce membrane recruitment and actin remodeling defects strikingly similar to nuf-derived embryos. These analyses support a common role for Nuf and Rab11 at the RE in membrane trafficking and actin remodeling during the initial stages of furrow formation.
胞质分裂需要皮质细胞骨架进行剧烈重塑以及细胞膜的添加。果蝇中心体周围蛋白“核沉降蛋白”（Nuf）在这两个过程之间建立了联系。在源自nuf的胚胎中，中期初始阶段和细胞沟形成过程中的肌动蛋白重塑及膜募集受到破坏。Nuf是arfophilin - 2的同源物，arfophilin - 2是一种ADP核糖基化因子效应蛋白，可结合Rab11并影响回收型内体（RE）的组织。在此，我们表明Nuf是RE的重要组成部分，且这些表型是Nuf在RE处发挥作用的结果。Nuf与关键的RE组分Rab11广泛共定位。GST下拉实验以及Nuf中保守的Rab11结合结构域的存在表明Nuf与Rab11存在物理关联。此外，Nuf和Rab11定位于RE相互需要。Rab11水平降低的胚胎产生的膜募集和肌动蛋白重塑缺陷与源自nuf的胚胎惊人地相似。这些分析支持了Nuf和Rab11在RE处对于沟形成初始阶段的膜运输和肌动蛋白重塑具有共同作用。
