Structural analysis of the α subunit of Na+/K+ ATPase genes in invertebrates

The Na+/K+ ATPase is a ubiquitous pump coordinating the transport of Na+ and K+ across the membrane of cells and its role is fundamental to cellular functions. It is heteromer in eukaryotes including two or three subunits (alpha, beta and gamma which is specific to the vertebrates). The catalytic functions of the enzyme have been attributed to the alpha subunit. Several complete a protein sequences are available, but only few gene structures were characterized. We identified the genomic sequences coding the alpha-subunit of the Na+/K+ ATPase, from the whole-genome shotgun contigs (WGS), NCBI Genomes (chromosome), Genomic Survey Sequences (GSS) and High Throughput Genomic Sequences (HTGS) databases across distinct phyla. One copy of the alpha subunit gene was found in Annelida, Arthropoda, Cnidaria, Echinodermata, Hemichordata, Mollusca, Placozoa, Porifera, Platyhelminthes, Urochordata, but the nematodes seem to possess 2 to 4 copies. The number of introns varied from 0 (Platyhelminthes) to 26 (Porifera); and their localization and length are also highly variable. Molecular phylogenies (Maximum Likelihood and Maximum Parsimony methods) showed some clusters constituted by (Chordata/(Echinodermata/ Hemichordata)) or (Plathelminthes/(Annelida/Mollusca)) and a basal position for Porifera. These structural analyses increase our knowledge about the evolutionary events of the alpha subunit genes in the invertebrates. (C) 2016 Elsevier Inc All rights reserved.