title: A transport and retention mechanism for the sustained distal localization of Spn-F-IKKε during Drosophila bristle elongation.
abstract: Stable localization of the signaling complex is essential for the robust morphogenesis of polarized cells. Cell elongation involves molecular signaling centers that coordinately regulate intracellular transport and cytoskeletal structures. In Drosophila bristle elongation, the protein kinase IKKε is activated at the distal tip of the growing bristle and regulates the shuttling movement of recycling endosomes and cytoskeletal organization. However, how the distal tip localization of IKKε is established and maintained during bristle elongation is unknown. Here, we demonstrate that IKKε distal tip localization is regulated by Spindle-F (Spn-F), which is stably retained at the distal tip and functions as an adaptor linking IKKε to cytoplasmic dynein. We found that Javelin-like (Jvl) is a key regulator of Spn-F retention. In jvl mutant bristles, IKKε and Spn-F initially localize to the distal tip but fail to be retained there. In S2 cells, particles that stain positively for Jvl or Spn-F move in a microtubule-dependent manner, whereas Jvl and Spn-F double-positive particles are immobile, indicating that Jvl and Spn-F are transported separately and, upon forming a complex, immobilize each other. These results suggest that polarized transport and selective retention regulate the distal tip localization of the Spn-F-IKKε complex during bristle cell elongation.
authors.affiliation: Laboratory for Morphogenetic Signaling, RIKEN Center for Developmental Biology, Kobe, Hyogo 650-0047, Japan otani@cdb.riken.jp shayashi@cdb.riken.jp.
authors.forename: Tetsuhisa
authors.initials: T
authors.lastname: Otani
authors.affiliation: Laboratory for Morphogenetic Signaling, RIKEN Center for Developmental Biology, Kobe, Hyogo 650-0047, Japan.
authors.forename: Kenzi
authors.initials: K
authors.lastname: Oshima
authors.affiliation: Laboratory for Morphogenetic Signaling, RIKEN Center for Developmental Biology, Kobe, Hyogo 650-0047, Japan.
authors.forename: Akiyo
authors.initials: A
authors.lastname: Kimpara
authors.affiliation: Laboratory for Morphogenetic Signaling, RIKEN Center for Developmental Biology, Kobe, Hyogo 650-0047, Japan.
authors.forename: Michiko
authors.initials: M
authors.lastname: Takeda
authors.affiliation: Department of Life Sciences and the National Institute for Biotechnology in the Negev, Ben-Gurion University, Beer-Sheva 84105, Israel.
authors.forename: Uri
authors.initials: U
authors.lastname: Abdu
authors.affiliation: Laboratory for Morphogenetic Signaling, RIKEN Center for Developmental Biology, Kobe, Hyogo 650-0047, Japan Department of Biology, Kobe University Graduate School of Science, Kobe, Hyogo 657-8501, Japan otani@cdb.riken.jp shayashi@cdb.riken.jp.
authors.forename: Shigeo
authors.initials: S
authors.lastname: Hayashi
mesh_terms: D000825:Animal Structures / Q000166:cytology* / Q000254:growth & development* / Q000378:metabolism / Q000648:ultrastructure; D000818:Animals; D002460:Cell Line; D016764:Cell Polarity; D003593:Cytoplasm / Q000378:metabolism; D029721:Drosophila Proteins / Q000378:metabolism*; D004331:Drosophila melanogaster / Q000166:cytology* / Q000378:metabolism / Q000648:ultrastructure; D004398:Dyneins / Q000378:metabolism; D004843:Epistasis, Genetic; D051550:I-kappa B Kinase / Q000378:metabolism*; D008869:Microtubule-Associated Proteins / Q000378:metabolism*; D008870:Microtubules / Q000378:metabolism; D008954:Models, Biological; D011485:Protein Binding; D021381:Protein Transport
chemical_list: D029721:Drosophila Proteins; D008869:Microtubule-Associated Proteins; C510862:Spn-F protein, Drosophila; D051550:I-kappa B Kinase; C510861:IKKepsilon protein, Drosophila; D004398:Dyneins
keywords: Cell elongation; Cell polarity; Drosophila; Dynein; IKKε; Ik2