Endothelial adhesion molecule ESAM binds directly to the multidomain adaptor MAGI-1 and recruits it to cell contacts.
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.
Wegmann
Frank
F
Institute of Cell Biology, ZMBE, University of Muenster, 48149 Muenster, Germany.
Ebnet
Klaus
K
Du Pasquier
Louis
L
Vestweber
Dietmar
D
Butz
Stefan
S
D048868:Adaptor Proteins, Signal Transducing / Q000235:genetics / Q000378:metabolism; D033942:Adaptor Proteins, Vesicular Transport / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D017398:Alternative Splicing / Q000235:genetics; D000818:Animals; D001665:Binding Sites / Q000502:physiology; D016466:CHO Cells; D002448:Cell Adhesion / Q000502:physiology; D015815:Cell Adhesion Molecules / Q000235:genetics / Q000378:metabolism*; D002450:Cell Communication / Q000502:physiology; D045744:Cell Line, Tumor; D006224:Cricetinae; D042783:Endothelial Cells; D004730:Endothelium, Vascular / Q000378:metabolism; D051528:Guanylate Kinases; D006801:Humans; D046911:Macromolecular Substances; D008565:Membrane Proteins / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D051379:Mice; D008969:Molecular Sequence Data; D009703:Nucleoside-Phosphate Kinase / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D010802:Phylogeny; D011485:Protein Binding / Q000502:physiology; D017434:Protein Structure, Tertiary / Q000502:physiology; D017386:Sequence Homology, Amino Acid; D012689:Sequence Homology, Nucleic Acid; D019108:Tight Junctions / Q000378:metabolism*
D048868:Adaptor Proteins, Signal Transducing; D033942:Adaptor Proteins, Vesicular Transport; C496471:CNKSR3 protein, human; D015815:Cell Adhesion Molecules; C428190:Esam protein, mouse; D046911:Macromolecular Substances; D008565:Membrane Proteins; D009703:Nucleoside-Phosphate Kinase; D051528:Guanylate Kinases; C493280:Magi1 protein, mouse