Genome-Wide Screens in Saccharomyces cerevisiae Highlight a Role for Cardiolipin in Biogenesis of Mitochondrial Outer Membrane Multispan Proteins
Genome-Wide Screens in Saccharomyces cerevisiae Highlight a Role for Cardiolipin in Biogenesis of Mitochondrial Outer Membrane Multispan Proteins
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DOI：
10.1128/mcb.00107-15
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发表时间：
2015-09-01
影响因子：
5.3
通讯作者：
Rapaport, Doron
中科院分区：
文献类型：
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作者：
Sauerwald, Julia;Jores, Tobias;Rapaport, Doron
一组特殊的线粒体外膜蛋白通过多个螺旋片段跨越膜几次。这种多跨度蛋白质在它们靶向线粒体并插入线粒体之前在胞质核糖体上合成。以前的工作认识到进口受体Tom 70和线粒体进口（MIM）复合物，这两个居民的ESTA，需要这些蛋白质的最佳生物合成。然而，它们的参与不足以解释整个进口途径或其监管。为了确定其他因素参与ofMOMmultispan蛋白的生物合成，我们进行了互补的高通量视觉和生长筛选酿酒酵母。心磷脂（CL）合酶（Crd 1）出现在两个屏幕的候选人。我们的研究结果确实证明了crd 1 Delta细胞线粒体中多跨度蛋白Ugo 1，Scm 4和Om 14的稳态水平较低。重要的是，MOM单跨度蛋白不受此突变的影响。此外，缺乏Crd 1的细胞器在体外输入新合成的Ugo 1和Scm 4分子的能力较低。Crd 1位于线粒体内膜，与CDP-二酰甘油一起缩合磷脂酰甘油，以获得从头合成的CL分子。因此，我们的研究结果表明，CL是一个重要组成部分的生物合成ofMOMmultispan蛋白。
A special group of mitochondrial outer membrane (MOM) proteins spans the membrane several times via multiple helical segments. Such multispan proteins are synthesized on cytosolic ribosomes before their targeting to mitochondria and insertion into the MOM. Previous work recognized the import receptor Tom70 and the mitochondrial import (MIM) complex, both residents of the MOM, as required for optimal biogenesis of these proteins. However, their involvement is not sufficient to explain either the entire import pathway or its regulation. To identify additional factors that are involved in the biogenesis ofMOMmultispan proteins, we performed complementary high-throughput visual and growth screens in Saccharomyces cerevisiae. Cardiolipin (CL) synthase (Crd1) appeared as a candidate in both screens. Our results indeed demonstrate lower steady-state levels of the multispan proteins Ugo1, Scm4, and Om14 in mitochondria from crd1 Delta cells. Importantly, MOMsingle-span proteins were not affected by this mutation. Furthermore, organelles lacking Crd1 had a lower in vitro capacity to import newly synthesized Ugo1 and Scm4 molecules. Crd1, which is located in the mitochondrial inner membrane, condenses phosphatidylglycerol together with CDP-diacylglycerol to obtain de novo synthesized CL molecules. Hence, our findings suggest that CL is an important component in the biogenesis ofMOMmultispan proteins.