Coordination of membrane and microtubule dynamics during cytokinesis in Arabidopsis thaliana

初生植物细胞壁在后期和末期之间被放置在称为细胞板的瞬时膜室中。小泡向细胞板的运输是由植物特有的微管和肌动蛋白丝阵列驱动的，即成膜体。为了避免分裂细胞核，胞质分裂需要在空间和时间上与细胞周期相协调。由此产生的一个关键问题是膜和细胞骨架动力学如何协调，以及它们如何受到细胞周期信号的调节。在胞质分裂的遗传解剖中，我们发现细胞板生物发生受损的突变体在成膜体微管动力学方面存在缺陷。我们还发现，Sec 1/Munc 18（SM）蛋白KEULE，参与膜融合，是所需的成膜体微管的重组。我们建议通过抗体染色和实时成像，以及电子和聚焦离子束显微镜冷冻固定，冷冻替代样品，以进一步表征膜和微管组织和动态在一个大的集合中的多核分裂缺陷突变体。然后，我们建议测试的假设，KEULE相互作用与微管，与微管相关的蛋白质，电机和后期促进复合物。这将提供一个模型，膜融合事件是如何与微管动力学和细胞周期进程的线索在植物胞质分裂的背景下协调。

Primary plant cell walls are laid down between anaphase and telophase in a transient membrane compartment referred to as the cell plate. The transport of vesicles to the cell plate is driven by a plant-specific array of microtubules and actin filaments, the phragmoplast. To avoid bisecting the nucleus, cytokinesis needs to be coordinated with the cell cycle in space and in time. A crucial question that arises is how membrane and cytoskeletal dynamics are coordinated and how they are regulated by cell cycle cues. In a genetic dissection of cytokinesis, we found that mutants in which cell plate biogenesis is impaired have defects in phragmoplast microtubule dynamics. We also found that the Sec1/Munc18 (SM) protein KEULE, involved in membrane fusion, is required for the reorganization of phragmoplast microtubules. We propose to further characterize membrane and microtubule organization and dynamics in a large collection of cytokinesis-defective mutants via antibody stains and live imaging, as well as electron and focused ion beam microscopy on cryofixed, freeze substituted samples. We then propose to test the hypothesis that KEULE interacts with microtubules, with microtubule-associated proteins, with motors and with the anaphase promoting complex. This would provide a model for how membrane fusion events are coordinated with microtubule dynamics and cell cycle progression cues in the context of plant cytokinesis.