The fusion of early endosomes induces molecular-motor-driven tubule formation and fission

J Cell Sci. 2012 Apr 15;125(Pt 8):1910-9. doi: 10.1242/jcs.092569. Epub 2012 Feb 22.

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.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Cell Line
  • Dogs
  • Dyneins / metabolism*
  • Endocytosis
  • Endosomes / metabolism*
  • Humans
  • Kinesins / metabolism*
  • Membrane Fusion*
  • Microtubules / metabolism*
  • Molecular Motor Proteins / metabolism*
  • rab5 GTP-Binding Proteins / metabolism

Substances

  • KIF16B protein, human
  • Molecular Motor Proteins
  • Dyneins
  • Kinesins
  • rab5 GTP-Binding Proteins