Crucial mitochondrial impairment upon CDC48 mutation in apoptotic yeast
Crucial mitochondrial impairment upon CDC48 mutation in apoptotic yeast
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DOI：
10.1074/jbc.m513699200
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发表时间：
2006-09-01
影响因子：
4.8
通讯作者：
Ueffing, Marius
中科院分区：
文献类型：
--
作者：
Braun, Ralf J.;Zischka, Hans;Ueffing, Marius
CDC 48（cdc 48（S565 G））是内质网（ER）相关蛋白降解（ERAD）途径中必需的基因，其突变导致发现细胞凋亡是单细胞生物酿酒酵母（Saccharomyces cerevisiae）中的细胞死亡机制。阐明Cdc 48 p介导的细胞凋亡在酵母中是特别感兴趣的，因为Cdc 48 p是高度保守的酵母直向同源物的人valosin-containing蛋白（VCP），多聚谷氨酰胺疾病和肌病的病理效应。在这里，我们显示了在cdc 48 S565 G酵母菌株线粒体中的不同蛋白质组学改变。这些观察到的分子变化可能与这些细胞器的功能障碍，如cdc 48 S565 G细胞的呼吸功能缺陷所建议的。cdc 48 S565 G菌株中的线粒体功能障碍伴随着线粒体的结构损伤，其由细胞色素c在胞质溶胶中的积累和线粒体增大指示。我们证明了线粒体呼吸链的细胞色素bc（1）复合物主要产生活性氧的积累，这一复合物的抑制剂的使用表明。同时，出现半胱天冬酶样酶活性，表明半胱天冬酶在细胞死亡过程中的作用。这些数据首次有力地表明线粒体参与Cdc 48 p/VCP依赖性细胞凋亡。
Mutation in CDC48 (cdc48(S565G)), a gene essential in the endoplasmic reticulum (ER)-associated protein degradation (ERAD) pathway, led to the discovery of apoptosis as a mechanism of cell death in the unicellular organism Saccharomyces cerevisiae. Elucidating Cdc48p-mediated apoptosis in yeast is of particular interest, because Cdc48p is the highly conserved yeast orthologue of human valosin-containing protein (VCP), a pathological effector for polyglutamine disorders and myopathies. Here we show distinct proteomic alterations in mitochondria in the cdc48S565G yeast strain. These observed molecular alterations can be related to functional impairment of these organelles as suggested by respiratory deficiency of cdc48S565G cells. Mitochondrial dysfunction in the cdc48S565G strain is accompanied by structural damage of mitochondria indicated by the accumulation of cytochrome c in the cytosol and mitochondrial enlargement. We demonstrate accumulation of reactive oxygen species produced predominantly by the cytochrome bc(1) complex of the mitochondrial respiratory chain as suggested by the use of inhibitors of this complex. Concomitantly, emergence of caspase-like enzymatic activity occurs suggesting a role for caspases in the cell death process. These data strongly point for the first time to a mitochondrial involvement in Cdc48p/VCP-dependent apoptosis.