Role of membrane lipids and proteins in discocyte-echinocyte and -stomatocyte transformation of erythrocytes.
An approach toward elucidation of mechanism of shape changes in vitro of human erythrocytes was made by observing effects of artificial manipulations of outer leaflet of the membrane lipid bilayer or of the membrane proteins on the cell shape. Addition of exogenous amphiphilic lipids into the outer leaflet or splitting by exogenous phospholipase A2 of native phospholipids in it equally produced echinocytes, whereas removal of polar head groups of native phospholipids in the same leaflet produced stomatocytes and invaginated cells. By changing the pH of the suspending medium, the shape of erythrocytes treated with certain of these agents was further altered, suggesting participation of electric charges of the phospholipid polar head groups in this phenomenon. Some indirect evidences were obtained on possible participation of spectrin in these shape changes; manipulation of membrane proteins by certain SH reagents made spectrin less extractable by hypotonic saline and cells less susceptible to invaginating action of phospholipase C and of a cationic amphipathic drug, chlorpromazine.
D002746:Chlorpromazine / Q000494:pharmacology; D004591:Electrophoresis, Polyacrylamide Gel; D004910:Erythrocyte Membrane / Q000187:drug effects / Q000648:ultrastructure*; D004912:Erythrocytes / Q000648:ultrastructure*; D006801:Humans; D007700:Kinetics; D008051:Lipid Bilayers; D008563:Membrane Lipids / Q000097:blood*; D008565:Membrane Proteins / Q000097:blood*; D008855:Microscopy, Electron, Scanning; D010741:Phospholipases A; D054467:Phospholipases A2; D010743:Phospholipids / Q000494:pharmacology; D013049:Spectrin / Q000378:metabolism
D008051:Lipid Bilayers; D008563:Membrane Lipids; D008565:Membrane Proteins; D010743:Phospholipids; D013049:Spectrin; D010741:Phospholipases A; D054467:Phospholipases A2; D002746:Chlorpromazine