An Evolutionarily Conserved NPC Subcomplex, Which Redistributes in Part to Kinetochores in Mammalian Cells

• Published in: The Journal of cell biology Vol. 154; no. 6; pp. 1147 - 1160
• Main Authors: Belgareh, Naïma, Rabut, Gwénaël, Baï, Siau Wei, van Overbeek, Megan, Beaudouin, Joël, Daigle, Nathalie, Zatsepina, Olga V., Pasteau, Fabien, Labas, Valérie, Fromont-Racine, Micheline, Ellenberg, Jan, Doye, Valérie
• Format: Journal Article
• Language: English
• Published: United States Rockefeller University Press 17-09-2001; The Rockefeller University Press
• Subjects: Anaphase; Antibodies; Cell cycle; Cells; Cellular biology; Evolution, Molecular; HeLa Cells; Humans; Kinetochores; Kinetochores - chemistry; Kinetochores - metabolism; Kinetochores - physiology; Life Sciences; Mammals; Membrane Proteins; Membrane Proteins - chemistry; Membrane Proteins - metabolism; Membrane Proteins - physiology; Microscopy, Fluorescence; Mitosis; Molecules; Nuclear Envelope; Nuclear Envelope - metabolism; Nuclear membrane; Nuclear Pore; Nuclear Pore - chemistry; Nuclear Pore - genetics; Nuclear Pore - metabolism; Nuclear Pore Complex Proteins; Nuclear Proteins; Nuclear Proteins - chemistry; Nuclear Proteins - metabolism; Nuclear Proteins - physiology; Precipitin Tests; Protein Binding; Saccharomyces cerevisiae; Saccharomyces cerevisiae Proteins; Sequence Homology, Amino Acid; Two-Hybrid System Techniques
• ISSN: 0021-9525; 1540-8140
• DOI: 10.1083/jcb.200101081

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.