Erythrocyte membrane phosphorylation in sickle cell disease

Phosphorylation of erythrocyte membrane proteins was determined in patients with homozygous sickle cell disease. After incubation of ghosts with gamma-32P ATP, proteins were submitted to SDS-polyacrylamide gel electrophoresis. Three salient features appeared: (i) a decreased phosphorylation of spectrin bands; (ii) a significantly increased phosphorylation (P less than 0.001) of bands 4(5) and 4(8) in the absence of cAMP and (iii) a significantly increased phosphorylation (P less than 0.001) of bands 7 and 8, both in the absence and the presence of cAMP. Studies on reticulocyte rich blood showed that the first change appeared to be specifically related to the disease, whilst the second resulted from the rejuvenation of the red cell population. No definite conclusion could be drawn for the third alteration.