title: Distinct AAA-ATPase p97 complexes function in discrete steps of nuclear assembly.
abstract: Although nuclear envelope (NE) assembly is known to require the GTPase Ran, the membrane fusion machinery involved is uncharacterized. NE assembly involves formation of a reticular network on chromatin, fusion of this network into a closed NE and subsequent expansion. Here we show that p97, an AAA-ATPase previously implicated in fusion of Golgi and transitional endoplasmic reticulum (ER) membranes together with the adaptor p47, has two discrete functions in NE assembly. Formation of a closed NE requires the p97-Ufd1-Npl4 complex, not previously implicated in membrane fusion. Subsequent NE growth involves a p97-p47 complex. This study provides the first insights into the molecular mechanisms and specificity of fusion events involved in NE formation.
authors.affiliation: European Molecular Biology Laboratory, Meyerhofstrasse 1, D-69117 Heidelberg, Germany.
authors.forename: M
authors.initials: M
authors.lastname: Hetzer
authors.forename: H H
authors.initials: HH
authors.lastname: Meyer
authors.forename: T C
authors.initials: TC
authors.lastname: Walther
authors.forename: D
authors.initials: D
authors.lastname: Bilbao-Cortes
authors.forename: G
authors.initials: G
authors.lastname: Warren
authors.forename: I W
authors.initials: IW
authors.lastname: Mattaj
mesh_terms: D000251:Adenosine Triphosphatases / Q000378:metabolism*; D000818:Animals; D002352:Carrier Proteins / Q000378:metabolism; D004721:Endoplasmic Reticulum / Q000378:metabolism; D006056:Golgi Apparatus / Q000378:metabolism; D008561:Membrane Fusion / Q000502:physiology*; D009685:Nuclear Envelope / Q000201:enzymology*; D028861:Nuclear Pore Complex Proteins; D009687:Nuclear Proteins / Q000378:metabolism*; D029543:Nucleocytoplasmic Transport Proteins; D009865:Oocytes / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000378:metabolism; D033921:Vesicular Transport Proteins; D014981:Xenopus
chemical_list: D002352:Carrier Proteins; C104361:NPL4 protein, S cerevisiae; D028861:Nuclear Pore Complex Proteins; D009687:Nuclear Proteins; D029543:Nucleocytoplasmic Transport Proteins; D029701:Saccharomyces cerevisiae Proteins; C444652:UFD1 protein, S cerevisiae; D033921:Vesicular Transport Proteins; D000251:Adenosine Triphosphatases; C404942:p97 ATPase