Modulation of Rac localization and function by dynamin.
Modulation of Rac localization and function by dynamin.
复制标题
动力对 Rac 定位和功能的调节。
DOI：
10.1091/mbc.e03-01-0019
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发表时间：
2004
影响因子：
3.3
通讯作者：
Schwartz,MartinAlexander
中科院分区：
文献类型：
--
作者：
Schlunck,Günther;Damke,Hanna;Kiosses,WilliamB;Rusk,Nicole;Symons,MarcH;Waterman-Storer,ClareM;Schmid,SandraL;Schwartz,MartinAlexander
GTPase动力蛋白控制多种内吞途径，参与吞噬体、足囊体黏附和侵过体的形成，调控细胞骨架和细胞凋亡。Rac是小gtp酶Rho家族的一员，控制板足和局灶复合物的形成，这在细胞迁移和吞噬中至关重要。我们现在表明，即使Rac被激活，dynamin-2功能的破坏也会改变Rac的定位并抑制细胞扩散和板足的形成。显性阴性的K44A动力蛋白-2对纤维连接蛋白抑制细胞扩散和板足形成，但不阻断细胞粘附；特异性小干扰RNA对动力蛋白2的消耗以类似的方式抑制板足。Dyn2（K44A）诱导Rac从细胞边缘错定位到异常的背褶，并导致Rac总活性升高。Rac活性的荧光共振能量转移成像证实，在显性阴性dyn2（K44A）存在的情况下，Rac活性主要定位于异常背褶。Dyn2（K44A）诱导了承载膜结合Rac-GFP的管状结构的积累。在巨嗜小体上发现了组成性活性但不是野生型的GFP-Rac，并且发现rac依赖的血小板衍生生长因子诱导的巨嗜性细胞增多症被Dyn2（K44A）的表达所消除。这些数据表明动力蛋白在Rac运输中起着不可缺少的作用，使板足形成和细胞扩散成为可能。
The GTPase dynamin controls a variety of endocytic pathways, participates in the formation of phagosomes, podosomal adhesions, and invadopodia, and in regulation of the cytoskeleton and apoptosis. Rac, a member of the Rho family of small GTPases, controls formation of lamellipodia and focal complexes, which are critical in cell migration and phagocytosis. We now show that disruption of dynamin-2function alters Rac localization and inhibits cell spreading and lamellipodia formation even though Rac is activated. Dominant-negative K44A dynamin-2inhibited cell spreading and lamellipodia formation on fibronectin without blocking cell adhesion; dynamin-2depletion by specific small interfering RNA inhibited lamellipodia in a similar manner. Dyn2(K44A) induced Rac mislocalization away from cell edges, into abnormal dorsal ruffles, and led to increased total Rac activity. Fluorescence resonance energy transfer imaging of Rac activity confirmed its predominant localization to aberrant dorsal ruffles in the presence of dominant-negative dyn2(K44A). Dyn2(K44A) induced the accumulation of tubulated structures bearing membrane-bound Rac-GFP. Constitutively active but not wild-type GFP-Rac was found on macropinosomes and Rac-dependent, platelet-derived growth factor-induced macropinocytosis was abolished by Dyn2(K44A) expression. These data suggest an indispensable role of dynamin in Rac trafficking to allow for lamellipodia formation and cell spreading.