Plasma membrane vesicles from BHK and HL60 cells treated with merocyanine 540 and iodoacetamide.

Treatment of BHK or HL60 cell lines with merocyanine 540 in the presence of the sulphydryl blocker iodoacetamide caused budding of the cell surface to release vesicles about 50-100 nm in diameter which accounted for up to 25% of the total surface membrane lipid. Smaller amounts of vesicular material were released in the presence of fluoride and merocyanine 540. The vesicles had a membrane lipid composition which was characteristic of other purified plasma membranes, with large amounts of sphingomyelin, phosphatidylserine and cholesterol and low proportions of phosphatidylinositol, phosphatidylcholine, triacylglycerol and cholesterol ester. This procedure for the isolation of vesicles should be a general method for the purification of plasma membrane components from a wide range of different cell types.