title: Crenarchaeal CdvA forms double-helical filaments containing DNA and interacts with ESCRT-III-like CdvB.
abstract: BACKGROUND
  The phylum Crenarchaeota lacks the FtsZ cell division hallmark of bacteria and employs instead Cdv proteins. While CdvB and CdvC are homologues of the eukaryotic ESCRT-III and Vps4 proteins, implicated in membrane fission processes during multivesicular body biogenesis, cytokinesis and budding of some enveloped viruses, little is known about the structure and function of CdvA. Here, we report the biochemical and biophysical characterization of the three Cdv proteins from the hyperthermophilic archaeon Metallospherae sedula.
  
  
  RESULTS
  Using sucrose density gradient ultracentrifugation and negative staining electron microscopy, we evidenced for the first time that CdvA forms polymers in association with DNA, similar to known bacterial DNA partitioning proteins. We also observed that, in contrast to full-lengh CdvB that was purified as a monodisperse protein, the C-terminally deleted CdvB construct forms filamentous polymers, a phenomenon previously observed with eukaryotic ESCRT-III proteins. Based on size exclusion chromatography data combined with detection by multi-angle laser light scattering analysis, we demonstrated that CdvC assembles, in a nucleotide-independent way, as homopolymers resembling dodecamers and endowed with ATPase activity in vitro. The interactions between these putative cell division partners were further explored. Thus, besides confirming the previous observations that CdvB interacts with both CdvA and CdvC, our data demonstrate that CdvA/CdvB and CdvC/CdvB interactions are not mutually exclusive.
  
  
  CONCLUSIONS
  Our data reinforce the concept that Cdv proteins are closely related to the eukaryotic ESCRT-III counterparts and suggest that the organization of the ESCRT-III machinery at the Crenarchaeal cell division septum is organized by CdvA an ancient cytoskeleton protein that might help to coordinate genome segregation.
authors.affiliation: CNRS-EMBL-UJF, Unit of Virus Host Cell Interactions (UVHCI)-UMI 3265, Grenoble, France.
authors.forename: Christine
authors.initials: C
authors.lastname: Moriscot
authors.forename: Simonetta
authors.initials: S
authors.lastname: Gribaldo
authors.forename: Jean-Michel
authors.initials: JM
authors.lastname: Jault
authors.forename: Mart
authors.initials: M
authors.lastname: Krupovic
authors.forename: Julie
authors.initials: J
authors.lastname: Arnaud
authors.forename: Marc
authors.initials: M
authors.lastname: Jamin
authors.forename: Guy
authors.initials: G
authors.lastname: Schoehn
authors.forename: Patrick
authors.initials: P
authors.lastname: Forterre
authors.forename: Winfried
authors.initials: W
authors.lastname: Weissenhorn
authors.forename: Patricia
authors.initials: P
authors.lastname: Renesto
mesh_terms: D019843:Archaeal Proteins / Q000737:chemistry* / Q000302:isolation & purification / Q000378:metabolism* / Q000648:ultrastructure; D019641:DNA, Archaeal / Q000378:metabolism* / Q000648:ultrastructure; D056827:Endosomal Sorting Complexes Required for Transport / Q000378:metabolism*; D011485:Protein Binding; D055550:Protein Stability; D017433:Protein Structure, Secondary; D011994:Recombinant Proteins / Q000378:metabolism; D040681:Structural Homology, Protein; D016943:Sulfolobaceae / Q000378:metabolism*
chemical_list: D019843:Archaeal Proteins; D019641:DNA, Archaeal; D056827:Endosomal Sorting Complexes Required for Transport; D011994:Recombinant Proteins