Alterations in human erythrocyte shape and the state of spectrin and phospholipid phosphorylation induced by cholesterol depletion.

Cholesterol depletion of erythrocytes, obtained after incubation with phosphatidylcholine vesicles, induces in most of the experiments: (1) a discocytestomatocyte transformation as observed by scanning electron microscopy; (2) a specific decrease in spectrin phosphorylation of intact erythrocytes; (3) an increase in lipid phosphorylation. It is concluded that the effect of cholesterol on erythrocyte shape is probably mediated through its action on the activity o of membrane-bound enzymes, proteases or kinases.