CYTOCHROMES-C1 AND CYTOCHROMES-B2 ARE SORTED TO THE INTERMEMBRANE SPACE OF YEAST MITOCHONDRIA BY A STOP-TRANSFER MECHANISM
CYTOCHROMES-C1 AND CYTOCHROMES-B2 ARE SORTED TO THE INTERMEMBRANE SPACE OF YEAST MITOCHONDRIA BY A STOP-TRANSFER MECHANISM
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DOI：
10.1016/0092-8674(92)90292-k
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发表时间：
1992-05-29
期刊：
影响因子：
64.5
通讯作者：
SCHATZ, G
中科院分区：
文献类型：
--
作者：
GLICK, BS;BRANDT, A;SCHATZ, G
细胞色素c1和b2到达线粒体膜间隙的途径一直存在争议。根据“保守分选”假说，这些蛋白质首先通过外膜和内膜输入到基质中，然后再跨内膜重新转运。我们的数据反对这一模型：细胞色素c1和b2的进口中间体仅在内膜外发现；这些蛋白质的成熟不依赖于基质定位的Hsp60伴侣；在没有ATP的情况下，与任一种细胞色素的前序列相连的二氢叶酸还原酶被输入到膜间隙。我们得出结论，细胞色素c1和b2是通过一种机制进行分类的，在这种机制中，通过内膜的转位被前序列中的“停止-转移”信号阻止。滞留的中间产物可能与内膜中的蛋白质通道有关。
The pathway by which cytochromes c1 and b2 reach the mitochondrial intermembrane space has been controversial. According to the "conservative sorting" hypothesis, these proteins are first imported across both outer and inner membranes into the matrix, and then are retranslocated across the inner membrane. Our data argue against this model: import intermediates of cytochromes c1 and b2 were found only outside the inner membrane; maturation of these proteins was independent of the matrix-localized hsp60 chaperone; and dihydrofolate reductase linked to the presequence of either cytochrome was imported to the intermembrane space in the absence of ATP. We conclude that cytochromes c1 and b2 are sorted by a mechanism in which translocation through the inner membrane is arrested by a "stop-transfer" signal in the presequence. The arrested intermediates may be associated with a proteinaceous channel in the inner membrane.