Regulated exocytosis in neuroendocrine cells: A role for subplasmalemmal Cdc42/N-WASP-induced actin filaments
Regulated exocytosis in neuroendocrine cells: A role for subplasmalemmal Cdc42/N-WASP-induced actin filaments
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DOI：
10.1091/mbc.e03-06-0402
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发表时间：
2004-02-01
影响因子：
3.3
通讯作者：
Bader, MF
中科院分区：
文献类型：
--
作者：
Gasman, S;Chasserot-Golaz, S;Bader, MF
在神经内分泌细胞中，肌动蛋白重组是调节胞吐作用的先决条件。小GTP酶，Rho蛋白，代表潜在的候选人耦合肌动蛋白动力学的膜运输事件。我们以前报道过Cdc 42在嗜铬细胞的胞吐调节中起着积极的作用。本工作的目的是剖析分子效应器途径整合Cdc 42的肌动蛋白结构所需的神经内分泌细胞的分泌反应。使用PC 12细胞作为分泌模型，我们表明，Cdc 42在胞吐过程中被激活的质膜。组成型活性Cdc 42（L 61）突变体的表达增加了分泌反应，招募神经Wiskott-Aldrich综合征蛋白（N-WASP），并增强了质膜下区域的肌动蛋白聚合。此外，N-WASP的表达通过依赖于其在细胞外周诱导肌动蛋白聚合的能力的机制刺激分泌。最后，我们观察到，肌动蛋白相关蛋白-2/3（Arp 2/3）与分泌颗粒，它伴随颗粒的对接点在质膜细胞活化后。我们的研究结果表明，第一次促分泌素诱发的刺激诱导的顺序排序的Cdc 42，N-WASP，Arp 2/3颗粒和质膜之间的界面，从而提供了一个肌动蛋白结构，使胞吐机械更有效。
In neuroendocrine cells, actin reorganization is a prerequisite for regulated exocytosis. Small GTPases, Rho proteins, represent potential candidates coupling actin dynamics to membrane trafficking events. We previously reported that Cdc42 plays an active role in regulated exocytosis in chromaffin cells. The aim of the present work was to dissect the molecular effector pathway integrating Cdc42 to the actin architecture required for the secretory reaction in neuroendocrine cells. Using PC12 cells as a secretory model, we show that Cdc42 is activated at the plasma membrane during exocytosis. Expression of the constitutively active Cdc42(L61) mutant increases the secretory response, recruits neural Wiskott-Aldrich syndrome protein (N-WASP), and enhances actin polymerization in the subplasmalemmal region. Moreover, expression of N-WASP stimulates secretion by a mechanism dependent on its ability to induce actin polymerization at the cell periphery. Finally, we observed that actin-related protein-2/3 (Arp2/3) is associated with secretory granules and that it accompanies granules to the docking sites at the plasma membrane upon cell activation. Our results demonstrate for the first time that secretagogue-evoked stimulation induces the sequential ordering of Cdc42, N-WASP, and Arp2/3 at the interface between granules and the plasma membrane, thereby providing an actin structure that makes the exocytotic machinery more efficient.