The notch ligand Delta1 recruits Dlg1 at cell-cell contacts and regulates cell migration.
Delta1 acts as a membrane-bound ligand that interacts with the Notch receptor and plays a critical role in cell fate specification. By using peptide affinity chromatography followed by mass spectrometry, we have identified Dlg1 as a partner of the Delta1 C-terminal region. Dlg1 is a human homolog of the Drosophila Discs large tumor suppressor, a member of the membrane-associated guanylate kinase family of molecular scaffolds. We confirmed this interaction by co-immunoprecipitation experiments between endogenous Dlg1 and transduced Delta1 in a 3T3 cell line stably expressing Delta1. Moreover, we showed that deletion of a canonical C-terminal PDZ-binding motif (ATEV) in Delta1 abrogated this interaction. Delta4 also interacted with Dlg1, whereas Jagged1, another Notch ligand, did not. In HeLa cells, transfected Delta1 triggered the accumulation of endogenous Dlg1 at sites of cell-cell contact. Expression of Delta1 also reduced the motility of 3T3 cells. Finally, deletion of the ATEV motif totally abolished these effects but did not interfere with the ability of Delta1 to induce Notch signaling and T cell differentiation in co-culture experiments. These results point to a new, probably cell-autonomous function of Delta1, which is independent of its activity as a Notch ligand.
Unité de Biologie Moléculaire de l'Expression Génique, URA 2582 CNRS, Institut Pasteur, 25 Rue du Dr Roux, 75724 Paris Cedex 15, France.
Emmanuelle M
EM
Six
Delphine
D
Ndiaye
Guido
G
Sauer
Yacine
Y
Laâbi
Rafika
R
Athman
Ana
A
Cumano
Christel
C
Brou
Alain
A
Israël
Frédérique
F
Logeat
D016475:3T3 Cells; D048868:Adaptor Proteins, Signal Transducing; D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D000818:Animals; D019921:Biotinylation; D002450:Cell Communication; D002454:Cell Differentiation; D002460:Cell Line; D002465:Cell Movement; D000074288:Discs Large Homolog 1 Protein; D004591:Electrophoresis, Polyacrylamide Gel; D005434:Flow Cytometry; D049452:Green Fluorescent Proteins / Q000378:metabolism; D051528:Guanylate Kinases; D006367:HeLa Cells; D006412:Hematopoietic Stem Cells / Q000378:metabolism; D006801:Humans; D015151:Immunoblotting; D047468:Immunoprecipitation; D047908:Intracellular Signaling Peptides and Proteins; D008024:Ligands; D013058:Mass Spectrometry; D008565:Membrane Proteins / Q000737:chemistry / Q000378:metabolism / Q000502:physiology*; D051379:Mice; D008856:Microscopy, Fluorescence; D008969:Molecular Sequence Data; D010957:Plasmids / Q000378:metabolism; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D011506:Proteins / Q000737:chemistry / Q000502:physiology*; D051880:Receptors, Notch; D017386:Sequence Homology, Amino Acid; D014162:Transfection; D014945:Wound Healing
D048868:Adaptor Proteins, Signal Transducing; C513314:DLG1 protein, human; D000074288:Discs Large Homolog 1 Protein; C000614189:Dlg1 protein, mouse; D047908:Intracellular Signaling Peptides and Proteins; D008024:Ligands; D008565:Membrane Proteins; D011506:Proteins; D051880:Receptors, Notch; C064045:delta protein; D049452:Green Fluorescent Proteins; D051528:Guanylate Kinases