Møller Annette B, Asp Torben, Holm Preben Bach, Palmgren Michael G
Department of Plant Biology, University of Copenhagen, Thorvaldsensvej 40, DK-1871 Frederiksberg C, Copenhagen, Denmark.
Mol Phylogenet Evol. 2008 Feb;46(2):619-34. doi: 10.1016/j.ympev.2007.10.023. Epub 2007 Nov 19.
Eukaryotes encompass a remarkable variety of organisms and unresolved lineages. Different phylogenetic analyses have lead to conflicting conclusions as to the origin and associations between lineages and species. In this work, we investigated evolutionary relationship of a family of cation pumps exclusive for the secretory pathway of eukaryotes by combining the identification of lineage-specific genes with phylogenetic evolution of common genes. Sequences of P5 ATPases, which are regarded to be cation pumps in the endoplasmic reticulum (ER), were identified in all eukaryotic lineages but not in any prokaryotic genome. Based on a protein alignment we could group the P5 ATPases into two subfamilies, P5A and P5B that, based on the number of negative charges in conserved trans-membrane segment 4, are likely to have different ion specificities. P5A ATPases are present in all eukaryotic genomes sequenced so far, while P5B ATPases appear to be lost in three eukaryotic lineages; excavates, entamoebas and land plants. A lineage-specific gene expansion of up to four different P5B ATPases is seen in animals.
真核生物包括各种各样的生物体和尚未解析的谱系。不同的系统发育分析对于谱系和物种之间的起源及关联得出了相互矛盾的结论。在这项研究中，我们通过将谱系特异性基因的鉴定与共同基因的系统发育进化相结合，研究了一类真核生物分泌途径特有的阳离子泵家族的进化关系。P5型ATP酶的序列，被认为是内质网（ER）中的阳离子泵，在所有真核生物谱系中都有发现，但在任何原核生物基因组中都未发现。基于蛋白质比对，我们可以将P5型ATP酶分为两个亚家族，P5A和P5B，基于保守跨膜片段4中的负电荷数量，它们可能具有不同的离子特异性。P5A ATP酶存在于迄今为止测序的所有真核生物基因组中，而P5B ATP酶似乎在三个真核生物谱系中丢失了；即盘状动物、内阿米巴和陆地植物。在动物中可以看到多达四种不同的P5B ATP酶的谱系特异性基因扩增。
