title: Electron cryotomography of ESCRT assemblies and dividing Sulfolobus cells suggests that spiraling filaments are involved in membrane scission.
abstract: The endosomal-sorting complex required for transport (ESCRT) is evolutionarily conserved from Archaea to eukaryotes. The complex drives membrane scission events in a range of processes, including cytokinesis in Metazoa and some Archaea. CdvA is the protein in Archaea that recruits ESCRT-III to the membrane. Using electron cryotomography (ECT), we find that CdvA polymerizes into helical filaments wrapped around liposomes. ESCRT-III proteins are responsible for the cinching of membranes and have been shown to assemble into helical tubes in vitro, but here we show that they also can form nested tubes and nested cones, which reveal surprisingly numerous and versatile contacts. To observe the ESCRT-CdvA complex in a physiological context, we used ECT to image the archaeon Sulfolobus acidocaldarius and observed a distinct protein belt at the leading edge of constriction furrows in dividing cells. The known dimensions of ESCRT-III proteins constrain their possible orientations within each of these structures and point to the involvement of spiraling filaments in membrane scission.
authors.affiliation: School of Natural Science, Hampshire College, Amherst, MA 01002, USA.
authors.forename: Megan J
authors.initials: MJ
authors.lastname: Dobro
authors.forename: Rachel Y
authors.initials: RY
authors.lastname: Samson
authors.forename: Zhiheng
authors.initials: Z
authors.lastname: Yu
authors.forename: John
authors.initials: J
authors.lastname: McCullough
authors.forename: H Jane
authors.initials: HJ
authors.lastname: Ding
authors.forename: Parkson Lee-Gau
authors.initials: PL
authors.lastname: Chong
authors.forename: Stephen D
authors.initials: SD
authors.lastname: Bell
authors.forename: Grant J
authors.initials: GJ
authors.lastname: Jensen
mesh_terms: D019843:Archaeal Proteins / Q000378:metabolism* / Q000648:ultrastructure; D002462:Cell Membrane / Q000502:physiology; D020285:Cryoelectron Microscopy; D048749:Cytokinesis; D055032:Electron Microscope Tomography; D056827:Endosomal Sorting Complexes Required for Transport / Q000378:metabolism* / Q000648:ultrastructure; D016944:Sulfolobus / Q000254:growth & development* / Q000378:metabolism / Q000648:ultrastructure
chemical_list: D019843:Archaeal Proteins; D056827:Endosomal Sorting Complexes Required for Transport