Regulation of Na+/K+ ATPase transport velocity by RNA editing

Because firing properties and metabolic rates vary widely,neurons require different transport rates from their na+/k+ pumps in order to maintain ion homeostasis. in this study we show that na+/k+ pump activity is tightly regulated by a novel process,rna editing. three codons within the squid na+/k+ atpase gene can be recoded at the rna level,and the efficiency of conversion for each varies dramatically,and independently,between tissues. at one site,a highly conserved isoleucine in the seventh transmembrane span can be converted to a valine,a change that shifts the pump's intrinsic voltage dependence. mechanistically,the removal of a single methyl group specifically targets the process of na+ release to the extracellular solution,causing a higher turnover rate at the resting membrane potential.