Centre de Recherche Public-Santé, Luxembourg, Luxembourg.
FEBS Lett. 2011 Jun 23;585(12):1821-7. doi: 10.1016/j.febslet.2011.05.019. Epub 2011 May 11.
We provide evidence that one of the 11 Arabidopsis actin-depolymerizing factors (ADFs), namely ADF9, does not display typical F-actin depolymerizing activity. Instead, ADF9 effectively stabilizes actin filaments in vitro and concomitantly bundles actin filaments with the highest efficiency under acidic conditions. Competition experiments show that ADF9 antagonizes ADF1 activity by reducing its ability to potentiate F-actin depolymerization. Accordingly, ectopic expression of ADF1 and ADF9 in tobacco cells has opposite effects. ADF1 severs actin filaments/bundles and promotes actin cytoskeleton disassembly, whereas ADF9 induces the formation of long bundles. Together these data reveal an additional degree of complexity in the comprehension of the biological functions of the ADF family and illustrate that antagonist activities can be displayed by seemingly equivalent actin-binding proteins.
我们提供的证据表明，拟南芥 11 种肌动蛋白解聚因子（ADFs）之一的 ADF9 并不表现出典型的 F-肌动蛋白解聚活性。相反，ADF9 在体外有效地稳定肌动蛋白丝，并在酸性条件下以最高效率使肌动蛋白丝成束。竞争实验表明，ADF9 通过降低其增强 F-肌动蛋白解聚的能力来拮抗 ADF1 的活性。因此，ADF1 和 ADF9 在烟草细胞中的异位表达具有相反的效果。ADF1 切断肌动蛋白丝/束并促进肌动蛋白细胞骨架解聚，而 ADF9 诱导长束的形成。这些数据共同揭示了对 ADF 家族生物学功能的理解的另一个复杂程度，并说明看似等效的肌动蛋白结合蛋白可以显示拮抗活性。
