Recruitment of cortexillin into the cleavage furrow is controlled by Rac1 and IQGAP-related proteins
Recruitment of cortexillin into the cleavage furrow is controlled by Rac1 and IQGAP-related proteins
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DOI：
10.1093/emboj/20.14.3705
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发表时间：
2001-07-16
期刊：
影响因子：
11.4
通讯作者：
Marriott, G
中科院分区：
文献类型：
--
作者：
Faix, J;Weber, I;Marriott, G
真核生物的胞质分裂受小的GTP结合蛋白的控制，尽管其潜在的分子机制还不完全清楚。皮质素是肌动蛋白结合蛋白，其活性对网骨藻的胞质分裂至关重要。在这里，我们表明，IQGAP相关和Rac 1结合蛋白DGAP 1特异性地与C-末端，肌动蛋白捆绑结构域的cortexillin I相互作用。与cortexillin I一样，DGAP 1在间期细胞的皮层中富集，并在胞质分裂期间易位到卵裂沟。活化形式的小GTTR Rac 1A将DGAP 1募集到具有皮质素I和II的四元复合物中。在DGAP 1（-）突变体中，仍然可以与第二个IQGAP相关蛋白GAPA形成复合物。然而，DGAP 1和GAPA的同时消除阻止了复合物的形成和皮质素到卵裂沟的定位。这导致胞质分裂中的严重缺陷，这与在皮质素I/II双无效突变体中发现的缺陷相似。我们的观察定义了一个新的和功能上重要的信号通路，是胞质分裂所需的。
Cytokinesis in eukaryotic organisms is under the control of small GTP-binding proteins, although the underlying molecular mechanisms are not fully understood. Cortexillins are actin-binding proteins whose activity is crucial for cytokinesis in Dictyostelium. Here we show that the IQGAP-related and Rac1-binding protein DGAP1 specifically interacts with the C-terminal, actin-bundling domain of cortexillin I. Like cortexillin I, DGAP1 is enriched in the cortex of interphase cells and translocates to the cleavage furrow during cytokinesis. The activated form of the small GTPase Rac1A recruits DGAP1 into a quaternary complex with cortexillin I and II. In DGAP1(-) mutants, a complex can still be formed with a second IQGAP-related protein, GAPA. The simultaneous elimination of DGAP1 and GAPA, however, prevents complex formation and localization of the cortexillins to the cleavage furrow. This leads to a severe defect in cytokinesis, which is similar to that found in cortexillin I/II double-null mutants. Our observations define a novel and functionally significant signaling pathway that is required for cytokinesis.