GRIM-19 is essential for maintenance of mitochondrial membrane potential
GRIM-19 is essential for maintenance of mitochondrial membrane potential
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DOI：
10.1091/mbc.e07-07-0683
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发表时间：
2008-05-01
影响因子：
3.3
通讯作者：
Cao, Xinmin
中科院分区：
文献类型：
--
作者：
Lu, Hao;Cao, Xinmin
GRIM-19被发现与线粒体呼吸链的复合体I结合，随后被证明参与了复合体I的组装和活性。为了进一步了解它在复合体I中的功能，我们通过产生一些缺失、截断和点突变来剖析它的功能结构域。线粒体定位序列位于N端。值得注意的是，70-80、90-100残基或整个C-末端区域(70-144)的缺失导致线粒体跨膜电位(Delta Psi M)的丧失。然而，另外两个复杂的I亚基NDUFA9和NDUFS3的类似缺失并没有表现出这种效应。我们还发现最后10个残基的缺失影响了GRIM-19‘S组装成复合体I的能力。我们构建了一个含有N-端60个残基和最后一个C-端10个残基的显性负向突变体，它可以组装成复合体I，但不能维持正常的Delta PSIm。过度表达该突变体的细胞不会自发死亡，但对细胞死亡因子诱导的细胞凋亡敏感。我们的结果表明，GRIM-19是复合物I的电子转移活性所必需的，并且GRIM-19突变体破坏Delta Psi m增强了细胞对凋亡刺激的敏感性。
GRIM-19 was found to copurify with complex I of mitochondrial respiratory chain and subsequently was demonstrated to be involved in complex I assembly and activity. To further understand its function in complex I, we dissected its functional domains by generating a number of deletion, truncation, and point mutants. The mitochondrial localization sequences were located at the N-terminus. Strikingly, deletion of residues 70-80, 90-100, or the whole C-terminal region (70-144) led to a loss of mitochondrial transmembrane potential (Delta Psi m). However, similar deletions of another two complex I subunits, NDUFA9 and NDUFS3, did not show such effect. We also found that deletion of the last 10 residues affected GRIM-19's ability to be assembled to complex I. We constructed a dominant-negative mutant containing the N-terminal 60 and the last C-terminal 10 residues, which could be assembled into complex I, but failed to maintain normal Delta Psi m. Cells overexpressing this mutant did not spontaneously undergo cell death, but were sensitized to apoptosis induced by cell death agents. Our results demonstrate that GRIM-19 is required for electron transfer activity of complex I, and disruption of Delta Psi m by GRIM-19 mutants enhances the cells' sensitivity to apoptotic stimuli.