The C-Terminus of Na⁺,K⁺-ATPase β-Subunit Contains a Hydrophobic Assembly Domain

Abstract

Assembly of catalytic α-subunits of Na⁺,K⁺-ATPase with β-subunits is a prerequisite for the structural and functional maturation of newly synthesized α-subunit and its intracellular transport from the ER to the plasma membrane (2). Little is known on the structural domains in α- and β-subunits that are involved in subunit assembly. Recently, Renaud et al (7) have reported that cytoplasmic and transmembrane deletion mutants of β-subunits are all able to assemble with α-subunits, provided that they are capable to insert into ER membranes. Together with the observation that deletions of 11 amino acids from the C-terminal ectodomain abolishes assembly (6), these results suggest that the C-terminal domain of β-subunits contain important structural information for subunit assembly.