passages.id: split_5_test_1100_passage
passages.type: progene_text
passages.text: These results illustrate the complexity of the regulation of Na , K-ATPase alpha1 isozymes by phorbol ester - sensitive PKCs and reveal 1 ) a phosphorylation - independent decrease in cell surface expression and 2 ) a phosphorylation - dependent stimulation of the transport activity attributable to an increase in the apparent Na affinity .