Arabidopsis Actin Depolymerizing Factor4 Modulates the Stochastic Dynamic Behavior of Actin Filaments in the Cortical Array of Epidermal Cells
Arabidopsis Actin Depolymerizing Factor4 Modulates the Stochastic Dynamic Behavior of Actin Filaments in the Cortical Array of Epidermal Cells
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DOI：
10.1105/tpc.111.090670
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发表时间：
2011-10-01
期刊：
影响因子：
11.6
通讯作者：
Staiger, Christopher J.
中科院分区：
文献类型：
--
作者：
Henty, Jessica L.;Bledsoe, Samuel W.;Staiger, Christopher J.
随着细胞需求的变化以及对生物和非生物刺激的反应，肌动蛋白丝阵列不断重塑。先前的研究表明，活的拟南芥表皮细胞的皮质阵列中的许多单肌动蛋白丝经历随机动力学，这是通过多产的切断活动的分解来平衡快速生长的组合。通过体外生化分析和简单的重构系统可以很好地理解丝的周转和动力学。然而，在活细胞中识别参与控制肌动蛋白动力学的分子参与者有待使用模型系统，特别是那些可以将遗传学的力量与高空间和时间分辨率的单个肌动蛋白丝的成像相结合的模型系统。在这里，我们测试了肌动蛋白解聚因子 (ADF)/cofilin 有助于随机丝断裂并促进肌动蛋白周转的假设。与野生型幼苗相比，拟南芥 ADF4 的敲除突变体具有更长的下胚轴和表皮细胞。这与肌动蛋白丝结构的变化有关。与野生型细胞相比，adf4 细胞中的细胞骨架阵列明显更密集且密度更低。单肌动蛋白丝周转的几个参数也发生了改变。值得注意的是，adf4 突变细胞的切断频率降低了 2.5 倍，并且肌动蛋白丝长度和寿命显着增加。因此，我们提供的证据表明 ADF4 有助于植物细胞中肌动蛋白丝的随机动态周转。
Actin filament arrays are constantly remodeled as the needs of cells change as well as during responses to biotic and abiotic stimuli. Previous studies demonstrate that many single actin filaments in the cortical array of living Arabidopsis thaliana epidermal cells undergo stochastic dynamics, a combination of rapid growth balanced by disassembly from prolific severing activity. Filament turnover and dynamics are well understood from in vitro biochemical analyses and simple reconstituted systems. However, the identification in living cells of the molecular players involved in controlling actin dynamics awaits the use of model systems, especially ones where the power of genetics can be combined with imaging of individual actin filaments at high spatial and temporal resolution. Here, we test the hypothesis that actin depolymerizing factor (ADF)/cofilin contributes to stochastic filament severing and facilitates actin turnover. A knockout mutant for Arabidopsis ADF4 has longer hypocotyls and epidermal cells when compared with wild-type seedlings. This correlates with a change in actin filament architecture; cytoskeletal arrays in adf4 cells are significantly more bundled and less dense than in wild-type cells. Several parameters of single actin filament turnover are also altered. Notably, adf4 mutant cells have a 2.5-fold reduced severing frequency as well as significantly increased actin filament lengths and lifetimes. Thus, we provide evidence that ADF4 contributes to the stochastic dynamic turnover of actin filaments in plant cells.