Wideman Jeremy G, Balacco Dario L, Fieblinger Tim, Richards Thomas A
Department of Biosciences, University of Exeter, Exeter, EX4 4QD, UK.
Wissenschaftskolleg zu Berlin, Berlin, 14193, Germany.
F1000Res. 2018 Jul 16;7:1088. doi: 10.12688/f1000research.15523.1. eCollection 2018.
Authors of a recent paper demonstrate that, like ERMES (ER-mitochondria encounter structure) in fungal cells, PDZD8 (PDZ domain containing 8) tethers mitochondria to the ER in mammalian cells. However, identifying PDZD8 as a "functional ortholog" of yeast Mmm1 (maintenance of mitochondrial morphology protein 1) is at odds with the phylogenetic data. PDZD8 and Mmm1 are paralogs, not orthologs, which affects the interpretation of the data with respect to the evolution of ER-mitochondria tethering. Our phylogenetic analyses show that PDZD8 co-occurs with ERMES components in lineages closely related to animals solidifying its identity as a paralog of Mmm1. Additionally, we identify two related paralogs, one specific to flagellated fungi, and one present only in unicellular relatives of animals. These results point to a complex evolutionary history of ER-mitochondria tethering involving multiple gene gains and losses in the lineage leading to animals and fungi.
最近一篇论文的作者表明，与真菌细胞中的内质网-线粒体接触结构（ERMES）类似，含PDZ结构域8（PDZD8）在哺乳动物细胞中将线粒体与内质网相连。然而，将PDZD8鉴定为酵母线粒体形态维持蛋白1（Mmm1）的“功能直系同源物”与系统发育数据不一致。PDZD8和Mmm1是旁系同源物，而非直系同源物，这影响了关于内质网-线粒体连接进化的数据解释。我们的系统发育分析表明，在与动物密切相关的谱系中，PDZD8与ERMES组分共同出现，巩固了其作为Mmm1旁系同源物的身份。此外，我们鉴定出两个相关的旁系同源物，一个特定于有鞭毛的真菌，另一个仅存在于动物的单细胞亲属中。这些结果表明内质网-线粒体连接具有复杂的进化历史，涉及导致动物和真菌的谱系中的多个基因得失。
