title: Nup53 is required for nuclear envelope and nuclear pore complex assembly.
abstract: Transport across the nuclear envelope (NE) is mediated by nuclear pore complexes (NPCs). These structures are composed of various subcomplexes of proteins that are each present in multiple copies and together establish the eightfold symmetry of the NPC. One evolutionarily conserved subcomplex of the NPC contains the nucleoporins Nup53 and Nup155. Using truncation analysis, we have defined regions of Nup53 that bind to neighboring nucleoporins as well as those domains that target Nup53 to the NPC in vivo. Using this information, we investigated the role of Nup53 in NE and NPC assembly using Xenopus egg extracts. We show that both events require Nup53. Importantly, the analysis of Nup53 fragments revealed that the assembly activity of Nup53 depleted extracts could be reconstituted using a region of Nup53 that binds specifically to its interacting partner Nup155. On the basis of these results, we propose that the formation of a Nup53-Nup155 complex plays a critical role in the processes of NPC and NE assembly.
authors.affiliation: Department of Cell Biology, University of Alberta, Edmonton, AB, Canada.
authors.forename: Lisa A
authors.initials: LA
authors.lastname: Hawryluk-Gara
authors.forename: Melpomeni
authors.initials: M
authors.lastname: Platani
authors.forename: Rachel
authors.initials: R
authors.lastname: Santarella
authors.forename: Richard W
authors.initials: RW
authors.lastname: Wozniak
authors.forename: Iain W
authors.initials: IW
authors.lastname: Mattaj
mesh_terms: D000818:Animals; D005260:Female; D006801:Humans; D066298:In Vitro Techniques; D008561:Membrane Fusion; D009154:Mutation; D009685:Nuclear Envelope / Q000378:metabolism*; D022022:Nuclear Pore / Q000378:metabolism*; D028861:Nuclear Pore Complex Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D009865:Oocytes / Q000378:metabolism; D010446:Peptide Fragments / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D054730:Protein Interaction Domains and Motifs; D025941:Protein Interaction Mapping; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D014981:Xenopus; D029867:Xenopus Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*
chemical_list: C506179:NUP155 protein, Xenopus; D028861:Nuclear Pore Complex Proteins; D010446:Peptide Fragments; D011993:Recombinant Fusion Proteins; D029867:Xenopus Proteins