The integral membrane nucleoporin pom121 functionally links nuclear pore complex assembly and nuclear envelope formation.
The metazoan nuclear envelope (NE) breaks down and reforms at each mitosis. Nuclear pore complexes (NPCs), which allow nucleocytoplasmic transport during interphase, assemble into the reforming NE at the end of mitosis. Using in vitro NE assembly assays, we show that one of the two transmembrane nucleoporins, pom121, is essential for NE formation, whereas the second, gp210, is dispensable. Depletion of either pom121-containing membrane vesicles or the protein alone does not affect vesicle binding to chromatin but prevents their fusion to form a closed NE. When the Nup107-160 complex, which is essential for integration of NPCs into the NE, is also depleted, pom121 becomes dispensable for NE formation, suggesting a close functional link between NPC and NE formation and the existence of a checkpoint that monitors NPC assembly state.
Antonin
Wolfram
W
European Molecular Biology Laboratory, Meyerhofstrasse 1, 69117 Heidelberg, Germany.
Franz
Cerstin
C
Haselmann
Uta
U
Antony
Claude
C
Mattaj
Iain W
IW
D000818:Animals; D001483:Base Sequence; D002478:Cells, Cultured; D018076:DNA, Complementary / Q000235:genetics; D005260:Female; D066298:In Vitro Techniques; D008561:Membrane Fusion / Q000502:physiology; D008562:Membrane Glycoproteins / Q000235:genetics / Q000502:physiology; D008565:Membrane Proteins / Q000235:genetics / Q000502:physiology*; D008954:Models, Biological; D009685:Nuclear Envelope / Q000502:physiology*; D022022:Nuclear Pore / Q000502:physiology*; D028861:Nuclear Pore Complex Proteins / Q000235:genetics / Q000502:physiology*; D009687:Nuclear Proteins / Q000235:genetics / Q000502:physiology*; D034741:RNA, Small Interfering / Q000235:genetics; D051381:Rats; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D014162:Transfection; D029867:Xenopus Proteins; D014982:Xenopus laevis
D018076:DNA, Complementary; D008562:Membrane Glycoproteins; D008565:Membrane Proteins; C512903:NUP210 protein, Xenopus; D028861:Nuclear Pore Complex Proteins; D009687:Nuclear Proteins; C082264:Pom121 protein, rat; D034741:RNA, Small Interfering; D011994:Recombinant Proteins; D029867:Xenopus Proteins