Key Laboratory of Cell Proliferation and Regulation Biology of Ministry of Education, College of Life Science, Beijing Normal University, Beijing 100875, China.
Key Laboratory of Cell Proliferation and Regulation Biology of Ministry of Education, College of Life Science, Beijing Normal University, Beijing 100875, China.
Mol Plant. 2018 Nov 5;11(11):1389-1399. doi: 10.1016/j.molp.2018.09.004. Epub 2018 Oct 6.
The process of pollen germination is crucial for flowering plant reproduction, but the mechanisms through which pollen grains establish polarity and select germination sites are not well understood. In this study, we report that a formin family protein, AtFH5, is localized to the vesicles and rotates ahead of Lifeact-mEGFP-labeled actin filaments during pollen germination. The translocation of AtFH5 to the plasma membrane initiates the assembly of a collar-like actin structure at the prospective germination site prior to germination. Genetic and pharmacological evidence further revealed an interdependent relationship between the mobility of AtFH5-labeled vesicles and the polymerization of actin filaments: vesicle-localized AtFH5 promotes actin assembly, and the polymerization and elongation of actin filaments, in turn, is essential for the mobility of AtFH5-labeled vesicles in pollen grains. Taken together, our work revealed a molecular mechanism underlying the polarity establishment and vesicle mobility during pollen germination.
花粉萌发的过程对开花植物的繁殖至关重要，但花粉粒如何建立极性并选择萌发部位的机制还不是很清楚。在这项研究中，我们报告称，formin 家族蛋白 AtFH5 定位于小泡中，并且在花粉萌发过程中，它在 Lifeact-mEGFP 标记的肌动蛋白丝之前旋转。AtFH5 向质膜的易位在萌发前启动了拟萌发部位帽状肌动蛋白结构的组装。遗传和药理学证据进一步揭示了 AtFH5 标记小泡的流动性和肌动蛋白丝聚合之间的相互依存关系：小泡定位的 AtFH5 促进肌动蛋白的组装，而肌动蛋白丝的聚合和伸长反过来又是花粉粒中 AtFH5 标记小泡流动性所必需的。总之，我们的工作揭示了花粉萌发过程中极性建立和小泡流动性的分子机制。
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