Death-associated protein 3 localizes to the mitochondria and is involved in the process of mitochondrial fragmentation during cell death
Death-associated protein 3 localizes to the mitochondria and is involved in the process of mitochondrial fragmentation during cell death
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DOI：
10.1074/jbc.m400041200
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发表时间：
2004-08-27
影响因子：
4.8
通讯作者：
Kimchi, A
中科院分区：
文献类型：
--
作者：
Mukamel, Z;Kimchi, A
死亡相关蛋白3（DAP 3）以前在我们的实验室中被分离出作为细胞死亡的正介导物。它是一种46 kDa的蛋白质，含有GTP结合结构域，该结构域被证明是诱导细胞死亡所必需的。DAP 3在受体信号传导复合物的下游发挥作用，其促死作用取决于胱天蛋白酶活性。最近的报道表明，DAP 3定位于线粒体，但迄今为止还没有报道这种定位的功能意义。本研究对人DAP 3（hDAP 3）的亚细胞定位和细胞功能进行了研究。我们发现，hDAP 3定位于线粒体，与细胞色素c相反，在几个细胞死亡信号后不会释放到细胞质中。hDAP 3的过表达诱导线粒体结构的急剧变化，包括线粒体碎片的增加。hDAP 3的线粒体定位和其GTP结合活性对于片段化是必不可少的。点状线粒体形态与用星形孢菌素处理HeLa细胞后观察到的相似。事实上，通过RNA干扰减少内源性hDAP 3蛋白部分减弱了星形孢菌素诱导的线粒体分裂。因此，hDAP 3是分子途径中的必要组分，其在碎裂的线粒体中达到高潮，可能反映了其参与裂变过程。这些结果首次提供了hDAP 3在线粒体维持中的特定功能作用。
Death-associated protein 3 (DAP3) was previously isolated in our laboratory as a positive mediator of cell death. It is a 46-kDa protein containing a GTP binding domain that was shown to be essential for the induction of cell death. DAP3 functions downstream of the receptor signaling complex, and its death-promoting effects depend on caspase activity. Recent reports have suggested that DAP3 is localized to the mitochondria, but no functional significance of this localization has been reported so far. Here, we study the sub-cellular localization and cellular function of human DAP3 (hDAP3). We found that hDAP3 is localized to the mitochondria and, in contrast to cytochrome c, is not released to the cytoplasm following several cell death signals. Overexpression of hDAP3 induced dramatic changes in the mitochondrial structure involving increased fragmentation of the mitochondria. Both the mitochondrial localization of hDAP3 and its GTP-binding activity were essential for the fragmentation. The punctiform mitochondrial morphology was similar to that observed upon treatment of HeLa cells with staurosporine. In fact, reduction of endogenous hDAP3 protein by RNA interference partially attenuated staurosporine-induced mitochondrial fission. Thus, hDAP3 is a necessary component in the molecular pathway that culminates in fragmented mitochondria, probably reflecting its involvement in the fission process. These results, for the first time, provide a specific functional role for hDAP3 in mitochondrial maintenance.