Isolation of Plasma Membrane Sheets and Plasma Membrane Domains from Rat Liver

The plasma membrane (PM) of polarized epithelial cells is composed of two physically continuous, but compositionally and functionally distinct domains: basolateral and apical. In hepatocytes, the basolateral domain includes the sinusoidal front, which faces the space of Disse and is involved in exchange of metabolites with the circulation, and the lateral surface, which is contiguous to neighboring hepatocytes. The apical or bile canalicular domain is specialized for the transport of bile acids and is separated from the basolateral domain by tight junctions, which prevent lateral diffusion of membrane proteins and outer leaflet lipids. Biochemical analysis of hepatocyte PM constituents requires the isolation of substantial amounts of this organelle.