Binding of Par-4 to the actin cytoskeleton is essential for Par-4/Dlk-mediated apoptosis
Binding of Par-4 to the actin cytoskeleton is essential for Par-4/Dlk-mediated apoptosis
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DOI：
10.1016/j.yexcr.2005.01.012
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发表时间：
2005-05-01
影响因子：
3.7
通讯作者：
Preuss, U
中科院分区：
文献类型：
--
作者：
Vetterkind, S;Illenberger, S;Preuss, U
前列腺凋亡反应-4(PAR-4)是一种38 kDa的蛋白，最初被认为是在前列腺癌细胞凋亡过程中上调的基因产物。PAR-4及其相互作用伙伴DAP样激酶(DLK)介导的细胞死亡以细胞骨架的剧烈变化为特征。为了揭示细胞骨架在PAR-4/DLK介导的细胞凋亡中的作用，我们分析了PAR-4与细胞骨架结构的直接关联。共聚焦荧光显微镜显示内源性PAR-4与大鼠成纤维细胞中的应激纤维特异性相关。体外共沉淀分析和体内FRET分析表明，PAR-4与F-肌动蛋白直接结合。肌动蛋白结合是由N-末端266个氨基酸介导的，但不需要PAR-4的C-末端区域，包括亮氨酸拉链和死亡结构域。此外，PAR-4与肌动蛋白细丝的相互作用在体外和体内都能形成肌动蛋白束。在大鼠成纤维细胞中，这种微丝结合对PAR-4的促凋亡功能是必不可少的，因为细胞松弛素D处理破坏了肌动蛋白细胞骨架，并使肌动蛋白结合受损的PAR-4结构过表达，导致PAR-4和DLK诱导的细胞凋亡显著减少。我们提出了一个模型，在这个模型中，PAR-4招募DLK来应激纤维，导致肌球蛋白II(MLC)调节轻链的增强磷酸化，并诱导细胞凋亡。(C)2005 Elsevier Inc.保留所有权利。
Prostate apoptosis response-4 (Par-4) is a 38-kDa protein originally identified as a gene product upregulated in prostate cancer cells undergoing apoptosis. Cell death mediated by Par-4 and its interaction partner DAP like kinase (Dlk) is characterized by dramatic changes of the cytoskeleton. To uncover the role of the cytoskeleton in Par-4/Dlk-mediated apoptosis, we analyzed Par-4 for a direct association with cytoskeletal structures. Confocal fluorescence microscopy revealed that endogenous Par-4 is specifically associated with stress fibers in rat fibroblasts. In vitro cosedimentation analyses and in vivo FRET analyses showed that Par-4 directly binds to F-actin. Actin binding is mediated by the N-terminal 266 amino acids, but does not require the C-terminal region of Par-4 containing the leucine zipper and the death domain. Furthermore, the interaction of Par-4 with actin filaments leads to the formation of actin bundles in vitro and in vivo. In rat fibroblasts, this microfilament association is essential for the pro-apoptotic function of Par-4, since both disruption of the actin cytoskeleton by cytochalasin D treatment and overexpression of Par-4 constructs impaired in actin binding result in a significant decrease of apoptosis induction by Par-4 and Dlk. We propose a model, in which Par-4 recruits Dlk to stress fibers, leading to enhanced phosphorylation of the regulatory light chain of myosin II (MLC) and to the induction of apoptosis. (c) 2005 Elsevier Inc. All rights reserved.