A novel type of regulation of the vimentin intermediate filament cytoskeleton by a Golgi protein
A novel type of regulation of the vimentin intermediate filament cytoskeleton by a Golgi protein
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DOI：
10.1078/0171-9335-00260
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发表时间：
2002-07-01
影响因子：
6.6
通讯作者：
Sztul, E
中科院分区：
文献类型：
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作者：
Gao, YS;Vrielink, A;Sztul, E
波形蛋白中间丝 (IF) 细胞骨架的高度动态结构是否会对细胞器的信号做出反应，以及哪些蛋白质可能参与此类事件，目前尚不清楚。我们之前已经证明，高尔基体蛋白亚氨基转移酶环脱氨酶 (FTCD) 在体内和体外与波形蛋白丝结合，并且 FTCD 的过度表达会导致波形蛋白 IF 细胞骨架的剧烈重排 (Gao 和 Sztul, J. Cell Biol. 152, 877 - 894, 2001)。使用实时成像，我们现在表明 FTCD 会导致单个较细的波形蛋白丝捆绑成纤维，并且这种捆绑总是起源于高尔基体。 FTCD 似乎是分子“粘合剂”，因为 FTCD 在体外交联波形蛋白丝。为了开始分析波形蛋白动力学中 FTCD 功能所需的结构决定因素，我们使用基于结构的设计来生成单独的亚氨基转移酶 (FT) 和环脱氨酶 (CD) 结构域，并产生酶促无活性的 FTCD。我们表明，完整的八聚体结构是 FTCD 与波形蛋白丝结合并促进丝组装所必需的，但消除酶活性并不影响 FTCD 对波形蛋白细胞骨架的作用。我们的研究结果表明，高尔基体蛋白 FTCD 是波形蛋白 IF 细胞骨架的有效调节剂，并表明高尔基体可能充当调节细胞骨架动力学的蛋白质的储存库。
Whether the highly dynamic structure of the vimentin intermediate filament (IF) cytoskeleton responds to cues from cellular organelles, and what proteins might participate in such events is largely unknown. We have shown previously that the Golgi protein formiminotransferase cyclodeaminase (FTCD) binds to vimentin filaments in vivo and in vitro, and that overexpression of FTCD causes dramatic rearrangements of the vimentin IF cytoskeleton (Gao and Sztul, J. Cell Biol. 152, 877 - 894, 2001). Using real-time imaging, we now show that FTCD causes bundling of individual thinner vimentin filaments into fibers and that the bundling always originates at the Golgi. FTCD appears to be the molecular "glue" since FTCD cross-links vimentin filaments in vitro. To initiate the analysis of structural determinants required for FTCD function in vimentin dynamics, we used structure-based design to generate individual formiminotransferase (FT) and cyclodeaminase (CD) domains, and to produce an enzymatically inactive FTCD. We show that the intact octameric structure is required for FTCD binding to vimentin filaments and for promoting filament assembly, but that eliminating enzymatic activity does not affect FTCD effects on the vimentin cytoskeleton. Our findings indicate that the Golgi protein FTCD is a potent modulator of the vimentin IF cytoskeleton, and suggest that the Golgi might act as a reservoir for proteins that regulate cytoskeletal dynamics.