Giardia mitosomes and trichomonad hydrogenosomes share a common mode of protein targeting
Giardia mitosomes and trichomonad hydrogenosomes share a common mode of protein targeting
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DOI：
10.1073/pnas.0500349102
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发表时间：
2005-08-02
影响因子：
11.1
通讯作者：
Tachezy, J
中科院分区：
文献类型：
--
作者：
Dolezal, P;Smid, O;Tachezy, J
线粒体是真核细胞内共生起源的典型细胞器。一些单细胞真核生物（原生生物）被认为主要是线粒体生物，在获得前线粒体内共生体之前从真核生物谱系中分离出来，但它们的线粒体地位最近受到线粒体样双膜结合细胞器（称为有丝体）的发现的挑战。在这里，我们报道了靶向肠贾第鞭毛虫核分裂体的蛋白质具有必要和足够的靶向信号，以被核分裂体蛋白输入机制识别。阴道毛滴虫的这些丝分裂体蛋白的表达导致靶向氢酶体，氢酶体是线粒体的一种产氢形式。我们在贾第鞭毛虫和毛滴虫中鉴定出与线粒体和加工肽酶的内膜转位酶成分相关的蛋白质。蛋白质靶向的共同模式支持了一种假设，即有丝体、氢酶体和线粒体代表了在不同的选择压力下进化的同一基本细胞器的不同形式。
Mitochondria are archetypal organelles of endosymbiotic origin in eukaryotic cells. Some unicellular eukaryotes (protists) were considered to be primarily amitochondrial organisms that diverged from the eukaryotic lineage before the acquisition of the premitochondrial endosymbiont, but their amitochondrial status was recently challenged by the discovery of mitochondria-like double membrane-bound organelles called mitosomes. Here, we report that proteins targeted into mitosomes of Giardia intestinalis have targeting signals necessary and sufficient to be recognized by the mitosomal protein import machinery. Expression of these mitosomal proteins in Trichomonas vaginalis results in targeting to hydrogenosomes, a hydrogen-producing form of mitochondria. We identify, in Giardia and Trichomonas, proteins related to the component of the translocase in the inner membrane from mitochondria and the processing peptidase. A shared mode of protein targeting supports the hypothesis that mitosomes, hydrogenosomes, and mitochondria represent different forms of the same fundamental organelle having evolved under distinct selection pressures.