title: Polarized exocytosis and transcytosis of Notch during its apical localization in Drosophila epithelial cells.
abstract: Notch (N) and its ligands, Delta (Dl) and Serrate (Ser), are transmembrane proteins that mediate the cell-cell interactions necessary for many cell-fate decisions. In Drosophila, N is predominantly localized to the apical portion of epithelial cells, but the mechanisms and functions of this localization are unknown. Here, we found N, Dl, and Ser were mostly located in the region from the subapical complex (SAC) to the apical portion of the adherens junctions (AJs) in wing disc epithelium. N was delivered to the SAC/AJs in two phases. First, polarized exocytosis specifically delivered nascent N to the apical plasma membrane and AJs in an O-fut1-independent manner. Second, N at the plasma membrane was relocated to the SAC/AJs by Dynamin- and Rab5-dependent transcytosis; this step required the O-fut1 function. Disruption of the apical polarity by Drosophila E-cadherin (DEcad) knock down caused N and Dl localization to the SAC/AJs to fail. N, but not Dl, formed a specific complex with DEcad in vivo. Finally, our results suggest that juxtacrine signaling in epithelia generally depends on the apicobasally polarized structure of epithelial cells.
authors.affiliation: Department of Biological Science and Technology, Tokyo University of Science, 2641 Yamazaki, Noda, Chiba 278-8510, Japan.
authors.forename: Nobuo
authors.initials: N
authors.lastname: Sasaki
authors.forename: Takeshi
authors.initials: T
authors.lastname: Sasamura
authors.forename: Hiroyuki O
authors.initials: HO
authors.lastname: Ishikawa
authors.forename: Maiko
authors.initials: M
authors.lastname: Kanai
authors.forename: Ryu
authors.initials: R
authors.lastname: Ueda
authors.forename: Kaoru
authors.initials: K
authors.lastname: Saigo
authors.forename: Kenji
authors.initials: K
authors.lastname: Matsuno
mesh_terms: D022005:Adherens Junctions / Q000378:metabolism; D000818:Animals; D015820:Cadherins / Q000235:genetics / Q000378:metabolism; D002135:Calcium-Binding Proteins / Q000378:metabolism; D002462:Cell Membrane / Q000378:metabolism; D016764:Cell Polarity / Q000502:physiology*; D004330:Drosophila / Q000502:physiology*; D029721:Drosophila Proteins / Q000032:analysis / Q000235:genetics / Q000378:metabolism*; D004705:Endocytosis; D004847:Epithelial Cells / Q000737:chemistry / Q000378:metabolism* / Q000648:ultrastructure; D005089:Exocytosis / Q000502:physiology*; D005647:Fucosyltransferases / Q000378:metabolism; D007091:Image Processing, Computer-Assisted; D007150:Immunohistochemistry; D036341:Intercellular Signaling Peptides and Proteins / Q000378:metabolism; D047908:Intracellular Signaling Peptides and Proteins; D000072100:Jagged-1 Protein; D008024:Ligands; D008565:Membrane Proteins / Q000378:metabolism; D008954:Models, Biological; D051880:Receptors, Notch / Q000032:analysis / Q000378:metabolism*; D000072099:Serrate-Jagged Proteins; D015398:Signal Transduction
chemical_list: D015820:Cadherins; D002135:Calcium-Binding Proteins; D029721:Drosophila Proteins; D036341:Intercellular Signaling Peptides and Proteins; D047908:Intracellular Signaling Peptides and Proteins; D000072100:Jagged-1 Protein; D008024:Ligands; D008565:Membrane Proteins; C497759:N protein, Drosophila; D051880:Receptors, Notch; C000606278:Ser protein, Drosophila; D000072099:Serrate-Jagged Proteins; C064045:delta protein; C501889:shg protein, Drosophila; D005647:Fucosyltransferases; C471275:O-fucosyltransferase 1, Drosophila