ASYMMETRIC MANIPULATION OF THE MEMBRANE LIPID BILAYER OF INTACT HUMAN-ERYTHROCYTES WITH PHOSPHOLIPASE-A, PHOSPHOLIPASE-C OR PHOSPHOLIPASE-D INDUCES A CHANGE IN CELL-SHAPE

Changes in the membrane morphology and phospholipid content of human erythrocytes were determined after incubation of intact cells with each of various exogeneous phospho-lipases (PLases). PLase A2 from Naja naja or bee venom induced crenation of the cells in parallel with hydrolysis of the membrane phosphatidylcholine (PC). This crenated cell shape was reversed to a biconcave disc or cup-like form by a further treatment with Iysophospho-lipase. In contrast, bacterial PLase C from Clostridium perfringens and Pseudomonas aureo-faciens or fungal PLase D from Streptomyces chromofuscus induced invagination of the cells in parallel with hydrolysis of the PC. The action of the latter group of PLases on the membrane morphology was counteracted by PLase A2, and vice versa. Thus, participation of the membrane lipid bilayer in the induction of membrane conformational change and hence cell shape change was demonstrated. © 1979, by the Japanese Biochemical Society.