Ubiquitination of Na,K-ATPase alpha 1 and alpha 2 subunits

Na,K-ATPase, an essential transporter of mammalian cells, is an oligomeric transmembrane protein composed of two subunits, alpha and beta, of which there are several isoforms. In this study, me demonstrate that the alpha 1 and alpha 2 isoforms of the Na,K-ATPase alpha subunit are modified by the covalent attachment of ubiquitin polymers in COS-7 cells. We propose that polyubiquitination of the Na,K-ATPase alpha subunit may play a role in regulating its degradation. (C) 1997 Federation of European Biochemical Societies.