Inducible Expression of the β1 Subunit of the Sodium Pump

The Na,K-ATPase, or sodium pump, a ubiquitous transmembrane enzyme in higher eukaryotes, consists of an α and a β subunit. Here we investigate the expression pattern of the two β isotypes in mouse B cell lines. Neither primary cells nor cell lines express β2. Abelson virus-transformed pre-B cells express β1, while B lymphomas and plasmacytomas do not. Thus, β1 expression in transformed cells follows that of their untransf ormed counterparts. Some subclones of pre-B cell line 70Z/3 express β1, and others do not, but lipopolysaccharide induces the β1-negative cells to become β1-positive.