Functional Genomics and Plant Molecular Imaging, Department of Life Sciences, Center for Protein Engineering (CIP), University of Liège Liège, Belgium ; PhytoSYSTEMS, University of Liège Liège, Belgium.
PhytoSYSTEMS, University of Liège Liège, Belgium ; Eukaryotic Phylogenomics, Department of Life Sciences, University of Liège Liège, Belgium.
Front Plant Sci. 2014 Jan 7;4:544. doi: 10.3389/fpls.2013.00544. eCollection 2013.
Metal ATPases are a subfamily of P-type ATPases involved in the transport of metal cations across biological membranes. They all share an architecture featuring eight transmembrane domains in pairs of two and are found in prokaryotes as well as in a variety of Eukaryotes. In Arabidopsis thaliana, eight metal P-type ATPases have been described, four being specific to copper transport and four displaying a broader metal specificity, including zinc, cadmium, and possibly copper and calcium. So far, few efforts have been devoted to elucidating the origin and evolution of these proteins in Eukaryotes. In this work, we use large-scale phylogenetics to show that metal P-type ATPases form a homogenous group among P-type ATPases and that their specialization into either monovalent (Cu) or divalent (Zn, Cd…) metal transport stems from a gene duplication that took place early in the evolution of Life. Then, we demonstrate that the four subgroups of plant metal ATPases all have a different evolutionary origin and a specific taxonomic distribution, only one tracing back to the cyanobacterial progenitor of the chloroplast. Finally, we examine the subsequent evolution of these proteins in green plants and conclude that the genes thoroughly characterized in model organisms are often the result of lineage-specific gene duplications, which calls for caution when attempting to infer function from sequence similarity alone in non-model organisms.
金属 ATP 酶是 P 型 ATP 酶家族的一个亚家族，参与金属阳离子在生物膜中的跨膜运输。它们都具有特征性的八跨膜结构域对，存在于原核生物和各种真核生物中。在拟南芥中，已经描述了八种金属 P 型 ATP 酶，其中四种是专门用于铜转运的，四种则具有更广泛的金属特异性，包括锌、镉，可能还有铜和钙。到目前为止，人们很少致力于阐明这些真核生物中蛋白质的起源和进化。在这项工作中，我们利用大规模系统发育学表明，金属 P 型 ATP 酶在 P 型 ATP 酶中形成一个同质群体，它们专门用于单价（Cu）或二价（Zn、Cd…）金属转运是由于基因复制，这种基因复制发生在生命进化的早期。然后，我们证明植物金属 ATP 酶的四个亚组都有不同的进化起源和特定的分类分布，只有一个可以追溯到叶绿体的蓝细菌祖先进化而来。最后，我们研究了这些蛋白质在绿色植物中的后续进化，并得出结论，在模式生物中得到充分研究的基因通常是谱系特异性基因复制的结果，这就要求在非模式生物中仅通过序列相似性推断功能时要谨慎。
