Isolation of plasma membrane exovesicles from BHK cells using merocyanine 540

Treatment of cultured BHK cells with merocyanine 540 caused the non-lytic release of vesicular material having the phospholipid composition characteristic of plasma membrane. The protein composition of the vesicles closely resembled that of the soluble fraction of the cell, as expected for exovesicles budding from the cell surface. Vesicles prepared from cells surface-iodinated with 125I contained no obvious iodinated membrane polypeptides, suggesting that no major proteins in the plasma membrane of the BHK cell are free to diffuse with lipids. The procedure described should represent a general method, applicable to a wide range of cell types, for isolating plasma membrane vesicles.