ROLE OF MEMBRANE TRAFFIC IN THE GENERATION OF EPITHELIAL CELL ASYMMETRY Epithelial cells have an apical–basolateral axis of polarity, which is required for epithelial functions including

barrier formation, vectorial ion transport and sensory perception. Here we review what is known about the sorting signals, machineries and pathways that maintain this asymmetry, and how

polarity proteins interface with membrane-trafficking pathways to generate membrane domains _de novo_.It is becoming apparent that membrane traffic does not simply reinforce polarity, but is

critical for the generation of cortical epithelial cell asymmetry. * Gerard Apodaca * Luciana I. Gallo * David M. Bryant