Sec6/8 Complex Is Recruited to Cell–Cell Contacts and Specifies Transport Vesicle Delivery to the Basal-Lateral Membrane in Epithelial Cells

• Published in: Cell Vol. 93; no. 5; pp. 731 - 740
• Main Authors: Grindstaff, Kent K, Yeaman, Charles, Anandasabapathy, Niroshana, Hsu, Shu-Chan, Rodriguez-Boulan, Enrique, Scheller, Richard H, Nelson, W.James
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 29.05.1998
• Subjects: Animals; Biological Transport; Carrier Proteins - metabolism; Cell Adhesion Molecules - metabolism; Cell Compartmentation; Cell Membrane - metabolism; Cell Polarity - physiology; Dogs; Epithelial Cells - metabolism; Golgi Apparatus - metabolism; Intercellular Junctions - physiology; Intracellular Membranes - metabolism; Kidney - cytology; Lipoproteins, LDL - metabolism; Molecular Weight; Nerve Growth Factors - metabolism; Protein Binding; Saccharomyces cerevisiae; Sec6/8 protein complex
• ISSN: 0092-8674; 1097-4172
• DOI: 10.1016/S0092-8674(00)81435-X

In budding yeast, the Sec6/8p complex is essential for generating cell polarity by specifying vesicle delivery to the bud tip. We show that Sec6/8 homologs are components of a cytosolic, ∼17S complex in nonpolarized MDCK epithelial cells. Upon initiation of calcium-dependent cell–cell adhesion, ∼70% of Sec6/8 is rapidly (t 1/2 ≈ 3–6 hr) recruited to sites of cell–cell contact. In streptolysin-O-permeabilized MDCK cells, Sec8 antibodies inhibit delivery of LDL receptor to the basal-lateral membrane, but not p75 NTR to the apical membrane. These results indicate that lateral membrane recruitment of the Sec6/8 complex is a consequence of cell–cell adhesion and is essential for the biogenesis of epithelial cell surface polarity.