Coordination of membrane and microtubule dynamics during cytokinesis in Arabidopsis thaliana

初代植物细胞壁在后期和末期之间的一个瞬时膜室中被称为细胞板。囊泡向细胞板的运输是由植物特有的微管阵列和肌动蛋白丝驱动的。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协调。出现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线索的调节。在细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膜质体微管动力学方面存在缺陷。我们还发现参与膜融合的Sec1/Munc18 （SM）蛋白KEULE是膜质体微管重组所必需的。我们建议通过抗体染色和活体成像，以及电子和聚焦离子束显微镜在冷冻固定和冷冻替代样品上进一步表征大量细胞动力学缺陷突变体中的膜和微管组织和动力学。然后，我们提出验证KEULE与微管、微管相关蛋白、马达和后期促进复合体相互作用的假设。这将为在植物细胞分裂的背景下，膜融合事件如何与微管动力学和细胞周期进程线索协调提供一个模型。

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.