Adrenergic stimulation of membrane protein phosphorylation in human erythrocytes

Adrenergic modification of membrane protein phosphorylation was studied in intact human erythrocytes. Micromolar norepinephrine increased 32P incorporation into Band 2 by 70%, and into Band 3 by 40%. Phosphorylation levels observed with a series of specific agonists and antagonists suggest that an alpha-adrenergic receptor is involved in this effect. The mechanism of linkage between this receptor and protein phosphorylation does not appear to involve modulation of intracellular concentrations of ATP, cyclic AMP, or cyclic GMP.