title: The fusion of early endosomes induces molecular-motor-driven tubule formation and fission.
abstract: Organelles in the endocytic pathway interact and communicate through the crucial mechanisms of fusion and fission. However, any specific link between fusion and fission has not yet been determined. To study the endosomal interactions with high spatial and temporal resolution, we enlarged the endosomes by two mechanistically different methods: by expression of the MHC-class-II-associated chaperone invariant chain (Ii; or CD74) or Rab5, both of which increased the fusion rate of early endosomes and resulted in enlarged endosomes. Fast homotypic fusions were studied, and immediately after the fusion a highly active and specific tubule formation and fission was observed. These explosive tubule formations following fusion seemed to be a direct effect of fusion. The tubule formations were dependent on microtubule interactions, and specifically controlled by Kif16b and dynein. Our results show that fusion of endosomes is a rapid process that destabilizes the membrane and instantly induces molecular-motor-driven tubule formation and fission.
authors.affiliation: Centre of Immune Regulation, Department of Molecular Biosciences, University of Oslo, Oslo, Norway.
authors.forename: Frode M
authors.initials: FM
authors.lastname: Skjeldal
authors.forename: Sten
authors.initials: S
authors.lastname: Strunze
authors.forename: Trygve
authors.initials: T
authors.lastname: Bergeland
authors.forename: Even
authors.initials: E
authors.lastname: Walseng
authors.forename: Tone F
authors.initials: TF
authors.lastname: Gregers
authors.forename: Oddmund
authors.initials: O
authors.lastname: Bakke
mesh_terms: D000818:Animals; D002460:Cell Line; D004285:Dogs; D004398:Dyneins / Q000378:metabolism*; D004705:Endocytosis; D011992:Endosomes / Q000378:metabolism*; D006801:Humans; D016547:Kinesins / Q000378:metabolism*; D008561:Membrane Fusion; D008870:Microtubules / Q000378:metabolism*; D020409:Molecular Motor Proteins / Q000378:metabolism*; D020696:rab5 GTP-Binding Proteins / Q000378:metabolism
chemical_list: C504670:KIF16B protein, human; D020409:Molecular Motor Proteins; D004398:Dyneins; D016547:Kinesins; D020696:rab5 GTP-Binding Proteins