Distinct AAA-ATPase p97 complexes function in discrete steps of nuclear assembly.
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.
Hetzer
M
M
European Molecular Biology Laboratory, Meyerhofstrasse 1, D-69117 Heidelberg, Germany.
Meyer
H H
HH
Walther
T C
TC
Bilbao-Cortes
D
D
Warren
G
G
Mattaj
I W
IW
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
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