The nuclear pore complexes (NPCs) are evolutionarily conserved assemblies that allow traffic between the cytoplasm and the nucleus. In this study, we have identified and characterized a novel human nuclear pore protein, hNup133, through its homology with the Saccharomyces cerevisiae nucleoporin scNup133. Two-hybrid screens and immunoprecipitation experiments revealed a direct and evolutionarily conserved interaction between Nup133 and Nup84/Nup107 and indicated that hNup133 and hNup107 are part of a NPC subcomplex that contains two other nucleoporins (the previously characterized hNup96 and a novel nucleoporin designated as hNup120) homologous to constituents of the scNup84 subcomplex. We further demonstrate that hNup133 and hNup107 are localized on both sides of the NPC to which they are stably associated at interphase, remain associated as part of a NPC subcomplex during mitosis, and are targeted at early stages to the reforming nuclear envelope. Throughout mitosis, a fraction of hNup133 and hNup107 localizes to the kinetochores, thus revealing an unexpected connection between structural NPCs constituents and kinetochores. Photobleaching experiments further showed that the mitotic cytoplasm contains kinetochore-binding competent hNup133 molecules and that in contrast to its stable association with the NPCs the interaction of this nucleoporin with kinetochores is dynamic.

Nup159p/Rat7p is an essential FG repeat-containing nucleoporin localized at the cytoplasmic face of the nuclear pore complex (NPC) and involved in poly(A)+ RNA export and NPC distribution. A detailed structural-functional analysis of this nucleoporin previously demonstrated that Nup159p is anchored within the NPC through its essential carboxyl-terminal domain. In this study, we demonstrate that Nup159p specifically interacts through this domain with both Nsp1p and Nup82p. Further analysis of the interactions within the Nup159p/Nsp1p/Nup82p subcomplex using the nup82Delta108 mutant strain revealed that a deletion within the carboxyl-terminal domain of Nup82p prevents its interaction with Nsp1p but does not affect the interaction between Nup159p and Nsp1p. Moreover, immunofluorescence analysis demonstrated that Nup159p is delocalized from the NPC in nup82Delta108 cells grown at 37 degrees C, a temperature at which the Nup82Delta108p mutant protein becomes degraded. This suggests that Nup82p may act as a docking site for a core complex composed of the repeat-containing nucleoporins Nup159p and Nsp1p. In vivo transport assays further revealed that nup82Delta108 and nup159-1/rat7-1 mutant strains have little if any defect in nuclear protein import and protein export. Together our data suggest that the poly(A)+ RNA export defect previously observed in nup82 mutant cells might be due to the loss from the NPCs of the repeat-containing nucleoporin Nup159p.

Biology of the CellVolume 90, Issue 1 p. 92-93 From nucleoporins to nuclear pore complexes: Functional analysis of the yearst Nup159/Nsp1/Nup82 subcomplex Naïma Belgareh, Naïma Belgareh UMR144 — Institut Curie, Paris, FranceSearch for more papers by this authorChristine Snay, Christine Snay Darmouth Medical School, NH, USASearch for more papers by this authorFabien Pasteau, Fabien Pasteau UMR144 — Institut Curie, Paris, FranceSearch for more papers by this authorSuzanne Dagher, Suzanne Dagher Darmouth Medical School, NH, USASearch for more papers by this authorCharles N. Cole, Charles N. Cole Darmouth Medical School, NH, USASearch for more papers by this authorValérie Doye, Valérie Doye UMR144 — Institut Curie, Paris, FranceSearch for more papers by this author Naïma Belgareh, Naïma Belgareh UMR144 — Institut Curie, Paris, FranceSearch for more papers by this authorChristine Snay, Christine Snay Darmouth Medical School, NH, USASearch for more papers by this authorFabien Pasteau, Fabien Pasteau UMR144 — Institut Curie, Paris, FranceSearch for more papers by this authorSuzanne Dagher, Suzanne Dagher Darmouth Medical School, NH, USASearch for more papers by this authorCharles N. Cole, Charles N. Cole Darmouth Medical School, NH, USASearch for more papers by this authorValérie Doye, Valérie Doye UMR144 — Institut Curie, Paris, FranceSearch for more papers by this author First published: 01 February 2012 https://doi.org/10.1016/S0248-4900(98)80238-4AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat No abstract is available for this article. Volume90, Issue1January 1998Pages 92-93 RelatedInformation