Biology Centre, Institute of Parasitology, Czech Academy of Sciences, and Faculty of Natural Sciences, University of South Bohemia, Ceské Budejovice (Budweis), Czech Republic.
Int J Parasitol. 2010 Jan;40(1):73-83. doi: 10.1016/j.ijpara.2009.07.008. Epub 2009 Aug 14.
Prohibitins (PHBs) 1 and 2 are small conserved proteins implicated in a number of functions in the mitochondrion, as well as in the nucleus of eukaryotic cells. The current understanding of PHB functions comes from studies of model organisms such as yeast, worm and mouse, but considerable debate remains with regard to the primary functions of these ubiquitous proteins. We exploit the tractable reverse genetics of Trypanosoma brucei, the causative agent of African sleeping sickness, in order to specifically analyse the function of PHB in this highly divergent eukaryote. Using inducible RNA interference (RNAi) we show that PHB1 is essential in T. brucei, where it is confined to the cell's single mitochondrion forming a high molecular weight complex. PHB1 and PHB2 appear to be indispensible for mitochondrial translation. Their ablation leads to a decrease in mitochondrial membrane potential, however no effect on the level of reactive oxygen species was observed. Flagellates lacking either PHB1 or both PHB1 and PHB2 exhibit significant morphological changes of their organelle, most notably its inflation. Even long after the loss of the PHB proteins, mtDNA was unaltered and mitochondrial cristae remained present, albeit displaced to the periphery of the mitochondrion, which is in contrast to other eukaryotes.
抑制素（PHBs）1 和 2 是小的保守蛋白，涉及到线粒体中的许多功能，以及真核细胞的核内功能。目前对 PHB 功能的认识来自于酵母、蠕虫和老鼠等模式生物的研究，但这些普遍存在的蛋白质的主要功能仍存在相当大的争议。我们利用引起非洲昏睡病的病原体——布鲁氏锥虫的可处理的反向遗传学，以便专门分析 PHB 在这种高度分化的真核生物中的功能。使用诱导性 RNA 干扰（RNAi），我们表明 PHB1 在 T. brucei 中是必需的，它局限于细胞的单个线粒体中，形成高分子量复合物。PHB1 和 PHB2 似乎对线粒体翻译是不可或缺的。它们的缺失导致线粒体膜电位下降，但未观察到对活性氧水平有影响。缺失 PHB1 或 PHB1 和 PHB2 的鞭毛生物表现出其细胞器的显著形态变化，最明显的是其膨胀。即使在 PHB 蛋白丢失很久之后，mtDNA 仍然未改变，线粒体嵴仍然存在，尽管移位到线粒体的外围，这与其他真核生物形成对比。
