Arp2/3 complex interactions and actin network turnover in lamellipodia
Arp2/3 complex interactions and actin network turnover in lamellipodia
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DOI：
10.1038/emboj.2008.34
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发表时间：
2008-04-09
期刊：
影响因子：
11.4
通讯作者：
Rottner, Klemens
中科院分区：
文献类型：
--
作者：
Lai, Frank P. L.;Szczodrak, Malgorzata;Rottner, Klemens
细胞迁移是由含有密集肌动蛋白丝网络的细胞质的板状伪足膜封闭片启动的。虽然网络周转的分子细节仍不清楚，最近的工作点在纤维成核Arp 2/3复合物及其激活剂WAVE复合物的关键作用。在这里，我们结合联合收割机荧光恢复后的光漂白（FRAP）的不同lamellipodial组件与一种新的数据分析方法，阐明肌动蛋白的动态组装/拆卸。我们发现，Arp 2/3复合物被纳入网络完全在板状伪足尖端，像肌动蛋白，在符合波复合物积累的网站。加帽蛋白同样表现出类似于肌动蛋白和Arp 2/3复合物的周转，但仅限于尖端。与此相反，corprin-另一个突出的Arp 2/3复合物调节剂-和ADF/cofilin -以前涉及驱动丝成核和拆卸-迅速交换整个lamellipodium。这些结果表明，Arp 2/3-和WAVE复合物驱动的肌动蛋白丝成核在板状伪足尖端是解耦的corpadrin和cofilin的活动。网络营业额还调节空间分离的活动，在尖端和cofilin在整个网格的加帽蛋白。
Cell migration is initiated by lamellipodia-membrane-enclosed sheets of cytoplasm containing densely packed actin filament networks. Although the molecular details of network turnover remain obscure, recent work points towards key roles in filament nucleation for Arp2/3 complex and its activator WAVE complex. Here, we combine fluorescence recovery after photobleaching (FRAP) of different lamellipodial components with a new method of data analysis to shed light on the dynamics of actin assembly/disassembly. We show that Arp2/3 complex is incorporated into the network exclusively at the lamellipodium tip, like actin, at sites coincident with WAVE complex accumulation. Capping protein likewise showed a turnover similar to actin and Arp2/3 complex, but was confined to the tip. In contrast, cortactin - another prominent Arp2/3 complex regulator - and ADF/cofilin - previously implicated in driving both filament nucleation and disassembly - were rapidly exchanged throughout the lamellipodium. These results suggest that Arp2/3- and WAVE complex-driven actin filament nucleation at the lamellipodium tip is uncoupled from the activities of both cortactin and cofilin. Network turnover is additionally regulated by the spatially segregated activities of capping protein at the tip and cofilin throughout the mesh.