UBIQUITINATION OF NA,K-ATPASE ALPHA-1 AND ALPHA-2 SUBUNITS

Na,K-ATPase, an essential transporter of mammalian cells, is an oligom eric transmembrane protein composed of two subunits, alpha and beta, o f 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 ce lls. We propose that polyubiquitination of the Na,K-ATPase alpha subun it may play a role in regulating its degradation. (C) 1997 Federation of European Biochemical Societies.