Phylogenetic analysis of Na+/K+ ATPase: Insight into the mechanism for the genesis of multi-isoforms of protein complex
Xue, CH（MOE Key Laboratory of Bioinformatics, Department of Automation, Tsinghua University）
Li-Ling, J（Department of Medical Genetics, China Medical University）
Li, QW（Laboratory of Comparative Genome and Bioinformatics, College of Life Science, Liaoning Normal University）
Li, YD（MOE Key Laboratory of Bioinformatics, Department of Automation, Tsinghua University）
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One most notable trend during the evolution is the substantial expansion of genomes along with dramatic expansion of protein diversity. It has been discovered that, whilst in prokaryotes subunits of many proteinases axe encoded by single genes, these are mostly encoded by multi-genes in eukaryotes. To understand the mechanism for the genesis of multi-isoforms of protein complex, we have analyzed amino acid sequences of Na+/K+ ATPase from various species ranging from archaea to vertebrates. Phylogenetic relationship between the selected species was considered from the perspective of important functional domains of Na+/K+ ATPase including cation ATPase N termination, E1-E2 ATPase, hydrolase, and cation ATPase C termination of the a subunit, Na+/K+ ATPase of the beta subunit, and ATP1G1_PLM_MAT8 of the gamma subunit. Coincident trees, obtained through comparison of aforementioned domains of the alpha and beta subunits, were used to examine the evolutionary divergence. By conservational and phylogenetic analyses, evolution of the Na+/K+ ATPase was outlined. Evidence was also found that essential domains of the Na+/K+ ATPase have been conserved during the evolution. These investigations seem to imply that various isoforms of alpha and beta subunits of vertebral Na+/K+ ATPases have evolved from single ancestral alpha and beta subunit genes through duplication events. In addition, our results seem to suggest a third fate for duplicated genes, e.g. the duplicate may have the same function as their ancestor gene. The results may also provide important clues to the underlying mechanisms of genesis of Na+/K+ ATPase multi-isoforms.
出处Journal of Biological Systems (2005) ，vol.13 no.3，pp299-312