Erythrocyte membrane phosphorylation in rats with spontaneous hypertension as affected by protein kinase C activator

: A study of orthophosphate incorporation into erythrocyte membrane proteins and lipids of spontaneously-hypertensive rats (SHR) at incubation of erythrocytes with 32PO4 and that of erythrocyte ghosts with 32P-gamma-ATP showed basal phosphorylation of proteins as well as polyphosphoinositides of erythrocyte ghosts to be essentially increased in SHRs as compared to normotensive animals, the differences being eliminated by the addition of protein kinase C activator (4 beta-phorbol-12 beta-myristate-13 alpha-acetate, PMA). After PMA-stimulated protein phosphorylation most of the label was incorporated into proteins of Band 4.1. There was no difference in basal phosphorylation of membrane proteins in case of intact erythrocytes. Under PMA stimulation, most of the label was incorporated into proteins of band 4.1 similarly to labelling of erythrocyte ghosts and a significant increment of radioactivity could only be seen in the control animals.