title: FIP3-endosome-dependent formation of the secondary ingression mediates ESCRT-III recruitment during cytokinesis.
abstract: The final cytokinesis event involves severing of the connecting intercellular bridge (ICB) between daughter cells. FIP3-positive recycling endosomes (FIP3 endosomes) and ESCRT complexes have been implicated in mediating the final stages of cytokinesis. Here we analyse the spatiotemporal dynamics of the actin cytoskeleton, FIP3-endosome fusion and ESCRT-III localization during cytokinesis to show that the ICB narrows by a FIP3-endosome-mediated secondary ingression, whereas the ESCRT-III complex is needed only for the last scission step of cytokinesis. We characterize the role of FIP3 endosomes during cytokinesis to demonstrate that FIP3 endosomes deliver SCAMP2/3 and p50RhoGAP to the ICB during late telophase, proteins required for the formation of the secondary ingression. We also show that the FIP3-endosome-induced secondary ingression is required for the recruitment of the ESCRT-III complex to the abscission site. Finally, we characterize a FIP3-endosome-dependent regulation of the ICB cortical actin network through the delivery of p50RhoGAP. These results provide a framework for the coordinated efforts of actin, FIP3 endosomes and the ESCRTs to regulate cytokinesis and abscission.
authors.affiliation: Department of Cell and Developmental Biology, School of Medicine, Anschutz Medical Campus, University of Colorado Denver, Aurora, Colorado 80045, USA.
authors.forename: John A
authors.initials: JA
authors.lastname: Schiel
authors.forename: Glenn C
authors.initials: GC
authors.lastname: Simon
authors.forename: Chelsey
authors.initials: C
authors.lastname: Zaharris
authors.forename: Julie
authors.initials: J
authors.lastname: Weisz
authors.forename: David
authors.initials: D
authors.lastname: Castle
authors.forename: Christine C
authors.initials: CC
authors.lastname: Wu
authors.forename: Rytis
authors.initials: R
authors.lastname: Prekeris
mesh_terms: D000199:Actins / Q000502:physiology; D002352:Carrier Proteins / Q000502:physiology; D048749:Cytokinesis; D003599:Cytoskeleton / Q000502:physiology; D056827:Endosomal Sorting Complexes Required for Transport / Q000502:physiology*; D011992:Endosomes / Q000502:physiology*; D020690:GTPase-Activating Proteins / Q000502:physiology; D006367:HeLa Cells; D006801:Humans; D051550:I-kappa B Kinase / Q000502:physiology*; D008565:Membrane Proteins / Q000502:physiology; D013692:Telophase / Q000502:physiology
chemical_list: D000199:Actins; D002352:Carrier Proteins; D056827:Endosomal Sorting Complexes Required for Transport; D020690:GTPase-Activating Proteins; C491731:IKBKG protein, human; D008565:Membrane Proteins; C466776:SCAMP2 protein, human; C109303:SCAMP3 protein, human; C085379:rho GTPase-activating protein; D051550:I-kappa B Kinase