Endothelial adhesion molecule ESAM binds directly to the multidomain adaptor MAGI-1 and recruits it to cell contacts

• Published in: Experimental cell research 2004-10, Vol.300 (1), p.121-133
• Main Authors: Wegmann, Frank, Ebnet, Klaus, Du Pasquier, Louis, Vestweber, Dietmar, Butz, Stefan
• Format: Article
• Language: English
• Subjects: Adaptor Proteins, Signal Transducing - genetics; Adaptor Proteins, Signal Transducing - metabolism; Adaptor Proteins, Vesicular Transport - genetics; Adaptor Proteins, Vesicular Transport - isolation & purification; Adaptor Proteins, Vesicular Transport - metabolism; Alternative Splicing - genetics; Animals; Binding Sites - physiology; Cell adhesion; Cell Adhesion - physiology; Cell Adhesion Molecules - genetics; Cell Adhesion Molecules - metabolism; Cell Communication - physiology; Cell Line, Tumor; CHO Cells; Cricetinae; Endothelial Cells; Endothelium, Vascular - metabolism; ESAM; Guanylate Kinases; Humans; Macromolecular Substances; MAGI-1; Membrane Proteins - genetics; Membrane Proteins - isolation & purification; Membrane Proteins - metabolism; Mice; Molecular Sequence Data; Nucleoside-Phosphate Kinase - genetics; Nucleoside-Phosphate Kinase - isolation & purification; Nucleoside-Phosphate Kinase - metabolism; Phylogeny; Protein Binding - physiology; Protein Structure, Tertiary - physiology; Sequence Homology, Amino Acid; Sequence Homology, Nucleic Acid; Tight junction; Tight Junctions - metabolism
• ISSN: 0014-4827; 1090-2422
• DOI: 10.1016/j.yexcr.2004.07.010

Endothelial cell-selective adhesion molecule (ESAM) is an immunoglobulin-like transmembrane protein associated with endothelial tight junctions (TJ). Based on a yeast two-hybrid screen, we have identified the membrane-associated guanylate kinase protein MAGI-1 as an intracellular binding partner of ESAM. MAGI-1 is a multidomain adaptor protein, which binds to transmembrane, cytoskeletal, and signaling molecules, and has been localized to tight junctions in epithelial cells. MAGI-1 associates with the very C-terminal sequence of ESAM most likely through a PDZ domain-mediated interaction. The direct interaction between ESAM and MAGI-1 was confirmed by pull-down experiments. The two proteins formed stable complexes in transfected Chinese hamster ovary (CHO) cells, which could be immunoisolated. We found MAGI-1 to be associated with cell–cell contacts in human umbilical vein endothelial cells (HUVECs) and in mouse endothelium, where it colocalizes with ESAM. In CHO cells, recruitment of MAGI-1 to cell contacts required the presence of ESAM. Hence, ESAM may be involved in anchoring MAGI-1 at endothelial tight junctions.