Abi mutants in Dictyostelium reveal specific roles for the SCAR/WAVE complex in cytokinesis
Abi mutants in Dictyostelium reveal specific roles for the SCAR/WAVE complex in cytokinesis
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DOI：
10.1016/j.cub.2008.01.026
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发表时间：
2008-02-12
期刊：
影响因子：
9.2
通讯作者：
Insall, Robert H.
中科院分区：
文献类型：
--
作者：
Pollitt, Alice Y.;Insall, Robert H.
肌动蛋白聚合驱动涉及运动和形状变化的多个细胞过程。 SCAR/WAVE 蛋白通过激活 Arp2/3 复合物将信号传导与肌动蛋白聚合连接起来。 SCAR/WAVE 通常与其他四种蛋白质形成复合物：PIR121、Nap1、Abi2 和 HSPC300（图 S1A 在线提供）[1-3]。然而，对于复合体是否作为一个不变的单位发挥作用，或者是否如 Eden 等人最初提出的那样，根据刺激而改变其组成，目前尚未达成共识。 [1]。目前还不清楚复杂成员是否专门调节 SCAR/WAVE，或者它们是否有其他目标 [4-6]。在这里，我们分析了独特的盘基网柄菌 Abi 的作用。我们发现 abiA 无效突变体在运动方面的缺陷比无疤痕细胞的严重程度要低，这表明出乎意料的是，SCAR 在没有 Abi 的情况下保留了部分活性。此外，abiA无效突变体在胞质分裂方面存在严重缺陷，这在其他SCAR复合体突变体中未见，只有当SCAR本身存在时才可见。详细检查表明，正常的胞质分裂需要 SCAR 活性，显然是通过多种途径调节的。
Actin polymerization drives multiple cell processes involving movement and shape change. SCAR/WAVE proteins connect signaling to actin polymerization through the activation of the Arp2/3 complex. SCAR/WAVE is normally found in a complex with four other proteins: PIR121, Nap1, Abi2, and HSPC300 (Figure S1A available online) [1-3]. However, there is no consensus as to whether the complex functions as an unchanging unit or if it alters its composition in response to stimulation, as originally proposed by Eden et al. [1]. It also is unclear whether complex members exclusively regulate SCAR/WAVEs or if they have additional targets [4-6]. Here, we analyze the roles of the unique Dictyostelium Abi. We find that abiA null mutants show less severe defects in motility than do scar null cells, indicating-unexpectedly-that SCAR retains partial activity in the absence of Abi. Furthermore, abiA null mutants have a serious defect in cytokinesis, which is not seen in other SCAR complex mutants and is seen only when SCAR itself is present. Detailed examination reveals that normal cytokinesis requires SCAR activity, apparently regulated through multiple pathways.