Dictyostelium Dock180-related RacGEFs regulate the actin cytoskeleton during cell motility.
Dictyostelium Dock180-related RacGEFs regulate the actin cytoskeleton during cell motility.
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盘基网柄菌 Dock180 相关的 RacGEF 在细胞运动过程中调节肌动蛋白细胞骨架。
DOI：
10.1091/mbc.e08-09-0899
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发表时间：
2009
影响因子：
3.3
通讯作者：
Firtel,RichardA
中科院分区：
文献类型：
--
作者：
Para,Alessia;Krischke,Miriam;Merlot,Sylvain;Shen,Zhouxin;Oberholzer,Michael;Lee,Susan;Briggs,Steven;Firtel,RichardA
阿米巴细胞的细胞运动是由局部的F-肌动蛋白聚合介导的，F-肌动蛋白聚合驱动膜突起的延长以促进向前运动。我们发现DictyosteliumDock180家族中的两个成员Docka和DockD的缺失会导致细胞趋化速度减慢。DOKA或DockD的表达弥补了DockD缺失细胞随机移动表型速度的减慢，提示DOKA和DockD可能是冗余的，在调节细胞运动方面具有相似的功能。在这方面，我们发现过表达DockD通过促进伪足延伸部位的F-肌动蛋白聚合来加快细胞速度。DockD在化学诱导剂刺激下定位于细胞皮质和迁移细胞的前沿，这种定位依赖于PI3K活性，提示DockD可能是连接PtdIns(3，4，5)P3产生和F-肌动蛋白聚合的途径的一部分。利用蛋白质组学方法，我们发现DdELMO1与DockD相关，并且在体内DockD底物中可能存在rac1a和rACC。总之，我们的工作为进一步了解细胞运动是如何控制的提供了证据，并证明了Dock180相关蛋白功能的分子机制在进化上是保守的。
Cell motility of amoeboid cells is mediated by localized F-actin polymerization that drives the extension of membrane protrusions to promote forward movements. We show that deletion of either of two members of theDictyosteliumDock180 family of RacGEFs, DockA and DockD, causes decreased speed of chemotaxing cells. The phenotype is enhanced in the double mutant and expression of DockA or DockD complements the reduced speed of randomly moving DockD null cells' phenotype, suggesting that DockA and DockD are likely to act redundantly and to have similar functions in regulating cell movement. In this regard, we find that overexpressing DockD causes increased cell speed by enhancing F-actin polymerization at the sites of pseudopod extension. DockD localizes to the cell cortex upon chemoattractant stimulation and at the leading edge of migrating cells and this localization is dependent on PI3K activity, suggesting that DockD might be part of the pathway that links PtdIns(3,4,5)P3production to F-actin polymerization. Using a proteomic approach, we found that DdELMO1 is associated with DockD and that Rac1A and RacC are possible in vivo DockD substrates. In conclusion, our work provides a further understanding of how cell motility is controlled and provides evidence that the molecular mechanism underlying Dock180-related protein function is evolutionarily conserved.