Plasma Membrane Polarity of Rat Hepatocyte in Primary Culture

Abstract

In vivo, hepatocytes are polarized epithelial cells. The bile canaliculi constitute the apical pole which is separated by tight junctions from the basal-lateral pole facing the blood. Specific proteins are asymmetrically distributed in the plasma membrane, thus defining the apical, basal, and lateral domains (Evans, 1980; Simons and Fuller, 1985). Such a polarized organization of the plasma membrane is the result of several processes including initial targeting, specific-domain recycling, and inter-domain exchanges of membrane constituents. Therefore, intracellular membrane traffic in polarized epithelial cells cannot be dissociated from cell polarity, a fact which must be taken into account especially when studies are made on in vitro models.