Nuclear pore complex assembly and maintenance in POM121- and gp210-deficient cells.
So far, POM121 and gp210 are the only known anchoring sites of vertebrate nuclear pore complexes (NPCs) within the lipid bilayer of the nuclear envelope (NE) and, thus, are excellent candidates for initiating the NPC assembly process. Indeed, we demonstrate that POM121 can recruit several nucleoporins, such as Nup62 or Nup358, to ectopic assembly sites. It thus appears to act as a nucleation site for the assembly of NPC substructures. Nonetheless, we observed functional NPCs and intact NEs in severely POM121-depleted cells. Double knockdowns of gp210 and POM121 in HeLa cells, as well as depletion of POM121 from human fibroblasts, which do not express gp210, further suggest that NPCs can assemble or at least persist in a POM121- and gp210-free form. This points to extensive redundancies in protein-protein interactions within NPCs and suggests that vertebrate NPCs contain additional membrane-integral nucleoporins for anchorage within the lipid bilayer of the NE. In Stavru et al., we describe such an additional transmembrane nucleoporin as the metazoan orthologue of yeast Ndc1p.
Stavru
Fabrizia
F
Zentrum für Molekulare Biologie der Universität Heidelberg, D-69120 Heidelberg, Germany.
Nautrup-Pedersen
Gitte
G
Cordes
Volker C
VC
Görlich
Dirk
D
D005347:Fibroblasts; D006367:HeLa Cells; D006801:Humans; D008562:Membrane Glycoproteins / Q000235:genetics*; D008563:Membrane Lipids / Q000378:metabolism; D018832:Molecular Chaperones / Q000378:metabolism; D022022:Nuclear Pore / Q000378:metabolism*; D028861:Nuclear Pore Complex Proteins / Q000378:metabolism; D009687:Nuclear Proteins / Q000235:genetics*; D034622:RNA Interference
D008562:Membrane Glycoproteins; D008563:Membrane Lipids; D018832:Molecular Chaperones; C063865:NUP210 protein, human; C510282:NUP62 protein, mouse; D028861:Nuclear Pore Complex Proteins; D009687:Nuclear Proteins; C512902:Nup210 protein, mouse; C094157:POM121 protein, human; C511307:POMZP3 protein, human; C094493:ran-binding protein 2