ChChd3, an inner mitochondrial membrane protein, is essential for maintaining crista integrity and mitochondrial function.
ChChd3, an inner mitochondrial membrane protein, is essential for maintaining crista integrity and mitochondrial function.
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ChChd3 是一种线粒体内膜蛋白，对于维持嵴完整性和线粒体功能至关重要。
DOI：
10.1074/jbc.m110.171975
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发表时间：
2011-01-28
期刊：
影响因子：
--
通讯作者：
Taylor SS
中科院分区：
文献类型：
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作者：
Darshi M;Mendiola VL;Mackey MR;Murphy AN;Koller A;Perkins GA;Ellisman MH;Taylor SS
线粒体内膜（IM）通过承载氧化磷酸化复合物机制（最显著地在嵴膜上）作为ATP产生的位点。嵴结构的破坏与多种心血管和神经退行性疾病有关。在此，我们表征了ChChd 3，一种先前鉴定的未知功能的PKA底物（Schauble，S.，金角C.的方法，Darshi，M.，科勒，A.，Shah，K.，和Taylor，S. S.（2007）J.Biol.Chem.282，14952-14959），并显示其对于维持嵴完整性和线粒体功能是必需的。在线粒体中，ChChd 3是IM的面向膜间隙的外周蛋白。在HeLa细胞中，ChChd 3的RNAi敲低导致线粒体片段化、OPA 1蛋白水平降低和融合受损，以及线粒体围绕细胞核沿着聚集并具有降低的生长速率。耗氧量和糖酵解速率均受到严重限制。这些细胞的超微结构分析显示异常的线粒体IM结构与碎片和管状嵴或嵴的损失，并减少嵴膜。此外，嵴连接开口直径减小至50%，表明在ChChd 3不存在的情况下嵴重塑。对ChChd 3结合蛋白的分析表明，ChChd 3与调节嵴形态的IM蛋白丝裂素和OPA 1以及调节β-桶蛋白在外膜上的输入和组装的外膜蛋白Sam 50相互作用。ChChd 3的敲除导致丝裂素和Sam 50蛋白几乎完全丧失，并且几种线粒体蛋白发生改变，这表明ChChd 3是一种支架蛋白，其稳定参与维持嵴结构和蛋白质输入的蛋白质复合物，因此对于维持线粒体结构和功能至关重要。
The mitochondrial inner membrane (IM) serves as the site for ATP production by hosting the oxidative phosphorylation complex machinery most notably on the crista membranes. Disruption of the crista structure has been implicated in a variety of cardiovascular and neurodegenerative diseases. Here, we characterize ChChd3, a previously identified PKA substrate of unknown function (Schauble, S., King, C. C., Darshi, M., Koller, A., Shah, K., and Taylor, S. S. (2007) J. Biol. Chem. 282, 14952–14959), and show that it is essential for maintaining crista integrity and mitochondrial function. In the mitochondria, ChChd3 is a peripheral protein of the IM facing the intermembrane space. RNAi knockdown of ChChd3 in HeLa cells resulted in fragmented mitochondria, reduced OPA1 protein levels and impaired fusion, and clustering of the mitochondria around the nucleus along with reduced growth rate. Both the oxygen consumption and glycolytic rates were severely restricted. Ultrastructural analysis of these cells revealed aberrant mitochondrial IM structures with fragmented and tubular cristae or loss of cristae, and reduced crista membrane. Additionally, the crista junction opening diameter was reduced to 50% suggesting remodeling of cristae in the absence of ChChd3. Analysis of the ChChd3-binding proteins revealed that ChChd3 interacts with the IM proteins mitofilin and OPA1, which regulate crista morphology, and the outer membrane protein Sam50, which regulates import and assembly of β-barrel proteins on the outer membrane. Knockdown of ChChd3 led to almost complete loss of both mitofilin and Sam50 proteins and alterations in several mitochondrial proteins, suggesting that ChChd3 is a scaffolding protein that stabilizes protein complexes involved in maintaining crista architecture and protein import and is thus essential for maintaining mitochondrial structure and function.