Potassium- or sodium-efflux ATPase, a key enzyme in the evolution of fungi
Potassium- or sodium-efflux ATPase, a key enzyme in the evolution of fungi
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DOI：
10.1099/00221287-148-4-933
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发表时间：
2002-04-01
期刊：
影响因子：
2.8
通讯作者：
Rodríguez-Navarro, A
中科院分区：
文献类型：
--
作者：
Benito, B;Garciadeblás, B;Rodríguez-Navarro, A
钾是细胞中最丰富的阳离子。因此，植物相关真菌和细胞内寄生虫永久或环境暴露于高K+，必须避免过量的K+积累激活K+外排系统。由于高K+和高pH值在自然环境中是相容的，自由生活的生物体不能保持永久的跨膜DeltapH，也不能像线粒体一样只依赖K+/H+反向转运蛋白。本研究表明粟酒裂殖酵母CTA 3是一种K+-外排ATP酶，其它真菌也具有Na+-外排ATP酶，它们也泵Na+。所有这些真菌ATP酶，包括那些只泵Na+，形成一个系统发育组，IID或ENA，P型ATP酶。通过检索数据库和部分克隆接合菌和担子菌中的ENA基因，作者认为可能所有的真菌都有ENA基因。这项研究表明，真菌的K+-或Na+-ATP酶进化的祖先K+-ATP酶，通过基因复制的过程。在酵母半子囊菌中，这些复制最近发生并产生双功能ATP酶，而在脉孢菌中，可能在其他真子囊菌中，它们在进化早期发生并产生专门的ATP酶。在裂殖酵母中，对Na+的适应不涉及K+-ATP酶的复制，因此它保留了一种可能接近于原始酶的酶。寄生虫利什曼原虫和锥虫具有与真菌K+-ATP酶遗传上相关的ATP酶，其可能是真菌酶的功能同源物。
Potassium is the most abundant cation in cells. Therefore, plant-associated fungi and intracellular parasites are permanently or circumstantially exposed to high K+ and must avoid excessive K+ accumulation activating K+ efflux systems. Because high K+ and high pH are compatible in natural environments, free-living organisms cannot keep a permanent transmembrane DeltapH and cannot rely only on K+/H+ antiporters, as do mitochondria. This study shows that the Schizosaccharomyces pombe CTA3 is a K+-efflux ATPase, and that other fungi are furnished with Na+-efflux ATPases, which also pump Na+. All these fungal ATPases, including those pumping only Na+, form a phylogenetic group, IID or ENA, among P-type ATPases. By searching in databases and partial cloning of ENA genes in species of Zygomycetes and Basidiomycetes, the authors conclude that probably all fungi have these genes. This study indicates that fungal K+- or Na+-ATPases evolved from an ancestral K+-ATPase, through processes of gene duplication. In yeast hemiascomycetes these duplications have occurred recently and produced bifunctional ATPases, whereas in Neurospora, and probably in other euascomycetes, they occurred earlier in evolution and produced specialized ATPases. In Schizosaccharomyces, adaptation to Na+ did not involve the duplication of the K+-ATPase and thus it retains an enzyme which is probably close to the original one. The parasites Leishmania and Trypanosoma have ATPases phylogenetically related to fungal K+-ATPases, which are probably functional homologues of the fungal enzymes.