The WASP Homologue Las17 Activates the Novel Actin-regulatory Activity of Ysc84 to Promote Endocytosis in Yeast
The WASP Homologue Las17 Activates the Novel Actin-regulatory Activity of Ysc84 to Promote Endocytosis in Yeast
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DOI：
10.1091/mbc.e08-09-0982
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发表时间：
2009-03-15
影响因子：
3.3
通讯作者：
Ayscough, Kathryn R.
中科院分区：
文献类型：
--
作者：
Robertson, Alastair S.;Allwood, Ellen G.;Ayscough, Kathryn R.
肌动蛋白在许多真核细胞过程中起着重要的作用，包括运动，极性的产生和膜运输。肌动蛋白在这些角色中的功能是通过与影响其聚合状态、动力学和组织的蛋白质的结合来调节的。许多蛋白质已被证明本地化与皮质补丁的酵母肌动蛋白在胞吞作用，但许多这些蛋白质的作用仍然知之甚少。在这里，我们揭示了酵母蛋白Ysc 84代表了一类新的肌动蛋白结合蛋白，从酵母到人类都是保守的。它包含一个新的N-末端肌动蛋白结合结构域称为Ysc 84肌动蛋白结合（YAB），它可以结合和捆绑肌动蛋白丝。有趣的是，全长Ysc 84单独不结合肌动蛋白，但结合可以激活酵母WASP同源物Las 17的聚脯氨酸区域内的特定基序。我们还确定了一个新的单体肌动蛋白结合位点的Las 17。Las 17和Ysc 84的多聚脯氨酸区可以共同促进肌动蛋白聚合。使用活细胞成像，在内吞位点的蛋白质的组装和拆卸的动力学进行了分析，并揭示了Ysc 84及其同源物Lsb 3的损失减少囊泡的向内运动，这与内吞过程中肌动蛋白聚合的作用一致。
Actin plays an essential role in many eukaryotic cellular processes, including motility, generation of polarity, and membrane trafficking. Actin function in these roles is regulated by association with proteins that affect its polymerization state, dynamics, and organization. Numerous proteins have been shown to localize with cortical patches of yeast actin during endocytosis, but the role of many of these proteins remains poorly understood. Here, we reveal that the yeast protein Ysc84 represents a new class of actin-binding proteins, conserved from yeast to humans. It contains a novel N-terminal actin-binding domain termed Ysc84 actin binding (YAB), which can bind and bundle actin filaments. Intriguingly, full-length Ysc84 alone does not bind to actin, but binding can be activated by a specific motif within the polyproline region of the yeast WASP homologue Las17. We also identify a new monomeric actin-binding site on Las17. Together, the polyproline region of Las17 and Ysc84 can promote actin polymerization. Using live cell imaging, kinetics of assembly and disassembly of proteins at the endocytic site were analyzed and reveal that loss of Ysc84 and its homologue Lsb3 decrease inward movement of vesicles consistent with a role in actin polymerization during endocytosis.