Shanghai Center for Plant Stress Biology, Chinese Academy of Sciences Center for Excellence in Molecular Plant Sciences, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 201602, People's Republic of China.
Center for Plant Cell Biology, Institute of Integrated Genome Biology, and Department of Botany and Plant Sciences, University of California, Riverside, California 92521.
Plant Physiol. 2018 Aug;177(4):1555-1568. doi: 10.1104/pp.18.00558. Epub 2018 Jul 5.
The dynamic arrangement of cortical microtubules (MTs) plays a pivotal role in controlling cell growth and shape formation in plants, but the mechanisms by which cortical MTs are organized to regulate these processes are not well characterized. In particular, the dynamic behavior of cortical MTs is critical for their spatial organization, yet the molecular mechanisms controlling MT dynamics remain poorly understood. In this study, we used the puzzle piece-shaped pavement cells of Arabidopsis () leaves as a model system in which to study cortical MT organization. We isolated an ethyl methanesulfonate mutant with reduced interdigitation of pavement cells in cotyledons. This line carried a mutation in (), which encodes a member of the plant-specific IQ motif protein family. Live-cell imaging and biochemical analyses demonstrated that IQD5 binds to MTs and promotes MT assembly. MT-depolymerizing drug treatment and in vivo MT dynamics assays suggested that IQD5 functions to stabilize MTs. Hence, our findings provide genetic, cell biological, and biochemical evidence that IQD5 regulates MT dynamics that affect MT organization and subsequent cell shape formation.
皮层微管（MTs）的动态排列在控制植物细胞生长和形状形成中起着关键作用，但皮层 MTs 如何组织以调节这些过程的机制尚不清楚。特别是，皮层 MTs 的动态行为对于其空间组织至关重要，但控制 MT 动力学的分子机制仍知之甚少。在这项研究中，我们使用棋盘状叶表皮细胞作为模型系统来研究皮层 MT 组织。我们分离到一个在子叶中表皮细胞交错减少的甲基磺酸乙酯突变体。该品系携带编码植物特异性 IQ 基序蛋白家族成员的突变。活细胞成像和生化分析表明，IQD5 与 MT 结合并促进 MT 组装。MT 解聚药物处理和体内 MT 动力学分析表明，IQD5 可稳定 MT。因此，我们的研究结果提供了遗传、细胞生物学和生化证据，表明 IQD5 调节影响 MT 组织和随后细胞形状形成的 MT 动力学。
