Membrane traffic in polarized epithelial cells

Epithelial cells contain apical and basolateral surfaces with distinct comp ositions. Sorting of certain proteins to the basolateral surface involves t he epithelial-specific mu 1b clathrin adaptor subunit. Recent results have shown that targeting to the basolateral surface utilizes the exocyst, where as traffic to the apical surface uses syntaxin 3. Endocytosis at the apical surface is regulated by ARF6. Transcytosis of IgA is regulated by the p62Y es tyrosine kinase.