title: Direct binding of cell polarity protein PAR-3 to cell-cell adhesion molecule nectin at neuroepithelial cells of developing mouse.
abstract: PAR-3 is a cell polarity protein that localizes at tight junctions (TJs) by direct binding to an immunoglobulin (Ig)-like cell-cell adhesion molecule JAM-1 in mammalian epithelial cells. Another Ig-like cell-cell adhesion molecule nectin plays a role in the localization of JAM-1 at TJs in epithelial cells. Nectin furthermore plays a role in the organization of adherens junctions (AJs) and TJs. Nectin comprises a family of four members, nectin-1, -2, -3, and -4. Nectins are associated with the actin cytoskeleton through afadin, of which the PDZ domain binds to nectins through their C-terminal four amino acids. We show here that PAR-3 binds to nectin-1 and -3 in neuroepithelial cells of the embryonic telencephalon, which are equipped with AJs, but not with typical TJs. Nectin-1, -2, -3, and afadin, but not JAM-1, were concentrated at AJs in neuroepithelial cells of the embryonic telencephalon at E13.5 and PAR-3 co-localized with nectins. PAR-3 was co-immunoprecipitated with nectin-1 and -3, but not with nectin-2 or JAM-1, from the mouse whole brain at E13.5. Recombinant PAR-3 stoichiometrically bound to recombinant nectin-1 and -3. The first one of the three PDZ domains of PAR-3 bound to the C-terminal four amino acids of nectin-1 and -3. The affinities of PAR-3 and afadin for nectin-1 and -3 were similar. Cadherin-deficient L cells expressing nectin-1 and -3 formed nectin-1- and -3-based cell-cell junctions, respectively, where PAR-3 as well as afadin was recruited. These results indicate that nectin-1 and -3 are involved in the localization of PAR-3 at AJs in the neuroepithelial cells of the embryonic telencephalon.
authors.affiliation: Department of Molecular Biology and Biochemistry, Osaka University Graduate School of Medicine/Faculty of Medicine, Suita 565-0871, Japan.
authors.forename: Kyoji
authors.initials: K
authors.lastname: Takekuni
authors.forename: Wataru
authors.initials: W
authors.lastname: Ikeda
authors.forename: Tsutomu
authors.initials: T
authors.lastname: Fujito
authors.forename: Koji
authors.initials: K
authors.lastname: Morimoto
authors.forename: Masakazu
authors.initials: M
authors.lastname: Takeuchi
authors.forename: Morito
authors.initials: M
authors.lastname: Monden
authors.forename: Yoshimi
authors.initials: Y
authors.lastname: Takai
mesh_terms: D048868:Adaptor Proteins, Signal Transducing; D000818:Animals; D001921:Brain / Q000196:embryology; D002352:Carrier Proteins / Q000378:metabolism*; D015815:Cell Adhesion Molecules; D018797:Cell Cycle Proteins; D016764:Cell Polarity / Q000502:physiology*; D004847:Epithelial Cells / Q000502:physiology* / Q000648:ultrastructure; D007381:Intermediate Filament Proteins / Q000378:metabolism*; D016547:Kinesins; D007739:L Cells; D051379:Mice; D008840:Microfilament Proteins / Q000378:metabolism; D016253:Microscopy, Immunoelectron; D009218:Myosins; D009419:Nerve Tissue Proteins; D064231:Nestin; D009474:Neurons / Q000502:physiology; D011485:Protein Binding; D011994:Recombinant Proteins / Q000378:metabolism; D017384:Sequence Deletion; D019108:Tight Junctions / Q000502:physiology / Q000648:ultrastructure
chemical_list: D048868:Adaptor Proteins, Signal Transducing; C490657:Afdn protein, mouse; D002352:Carrier Proteins; D015815:Cell Adhesion Molecules; D018797:Cell Cycle Proteins; D007381:Intermediate Filament Proteins; D008840:Microfilament Proteins; D009419:Nerve Tissue Proteins; C577485:Nes protein, mouse; D064231:Nestin; C115084:Pard3 protein, mouse; D011994:Recombinant Proteins; C108835:afadin; D009218:Myosins; D016547:Kinesins