Biochemical analysis of a caveolae-enriched plasma membrane fraction from rat liver

We isolated and characterized a subcellular fraction derived from the blood -sinusoidal plasma membrane of hepatocytes enriched in caveolin and contain ing several of the molecular components described to be present in caveolae isolated from other cell types. A morphological study by electron microsco py revealed that it was composed of caveolae-attached membrane profiles. Im munoelectron microscopy of isolated fraction showed the specific labeling o f internal caveolae membranes with anti-caveolin antibody. Finally, one- an d two-dimensional electrophoresis and Western blotting were used for the bi ochemical analysis of this new rat liver plasma membrane fraction. From the biochemical and the morphological characterization, we conclude that the c aveolae-enriched plasma membrane fraction is a plasma membrane fraction, wh ich originates from specialized regions of the sinusoidal plasma membrane, enriched in caveolae.