Molecular Architecture of the Transport Channel of the Nuclear Pore Complex

Laboratory of Cell Biology, Howard Hughes Medical Institute, The Rockefeller University, 1230 York Avenue, New York, NY 10065, USA.
Cell (Impact Factor: 32.24). 10/2011; 147(3):590-602. DOI: 10.1016/j.cell.2011.09.034
Source: PubMed


The nuclear pore complex encloses a central channel for nucleocytoplasmic transport, which is thought to consist of three nucleoporins, Nup54, Nup58, and Nup62. However, the structure and composition of the channel are elusive. We determined the crystal structures of the interacting domains between these nucleoporins and pieced together the molecular architecture of the mammalian transport channel. Located in the channel midplane is a flexible Nup54⋅Nup58 ring that can undergo large rearrangements yielding diameter changes from ∼20 to ∼40 nm. Nup62⋅Nup54 triple helices project alternately up and down from either side of the midplane ring and form nucleoplasmic and cytoplasmic entries. The channel consists of as many as 224 copies of the three nucleoporins, amounting to a molar mass of 12.3 MDa and contributing 256 phenylalanine-glycine repeat regions. We propose that the occupancy of these repeat regions with transport receptors modulates ring diameter and transport activity.

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    • "Indeed, we note that O-GlcNAc is found on over 18 Nups but is most abundant on peripheral Nups (Supplementary Figure S8 and Table S1). O-GlcNAc on Nups is predominantly observed in regions that are not structurally defined except for Nup62, where residue T376 is in an a-helical domain (Solmaz et al., 2011), and Nup98, where residue T184 has been noted in a b-sheet structure (Ren et al., 2010). Accordingly, lower "
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    ABSTRACT: O-glycosylation of the nuclear pore complex (NPC) by O-linked N-acetylglucosamine (O-GlcNAc) is conserved within metazoans. Many nucleoporins (Nups) comprising the NPC are constitutively O-GlcNAcylated, but the functional role of this modification remains enigmatic. We show that loss of O-GlcNAc, induced by either inhibition of O-GlcNAc transferase (OGT) or deletion of the gene encoding OGT, leads to decreased cellular levels of a number of natively O-GlcNAcylated Nups. Loss of O-GlcNAc enables increased ubiquitination of these Nups and their increased proteasomal degradation. The decreased half-life of these deglycosylated Nups manifests in their gradual loss from the NPC and a downstream malfunction of the nuclear pore selective permeability barrier in both dividing and post-mitotic cells. These findings define a critical role of O-GlcNAc modification of the NPC in maintaining its composition and the function of the selectivity filter. The results implicate NPC glycosylation as a regulator of NPC function and reveal the role of conserved glycosylation of the NPC among metazoans. © The Author (2015). Published by Oxford University Press on behalf of Journal of Molecular Cell Biology, IBCB, SIBS, CAS. All rights reserved.
    Full-text · Article · Jun 2015 · Journal of Molecular Cell Biology
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    • "It remains to be determined how these truncated proteins specifically impact nuclear transport in Arabidopsis. A structural analysis of the rat NUP62 subcomplex indicates that NUP54 individually binds both NUP62 and NUP58 to form the intact NUP62 complex (Solmaz et al., 2011). These authors show that NUP62 and NUP54 interact by their N-terminal domains, so it is feasible that the truncated NUP62 and NUP54 proteins are still able to make this interaction in Arabidopsis. "
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    ABSTRACT: The nuclear pore complex (NPC) is a multisubunit protein conglomerate that facilitates movement of RNA and protein between the nucleus and cytoplasm. Relatively little is known regarding the influence of the Arabidopsis NPC on growth and development. Seedling development, flowering time, nuclear morphology, mRNA accumulation, and gene expression changes in Arabidopsis nucleoporin mutants were investigated. Nuclear export of mRNA is differentially affected in plants with defects in nucleoporins that lie in different NPC subcomplexes. This study reveals differences in the manner by which nucleoporins alter molecular and plant growth phenotypes, suggesting that nuclear pore subcomplexes play distinct roles in nuclear transport and reveal a possible feedback relationship between the expression of genes involved in nuclear transport.
    Full-text · Article · Aug 2014 · Journal of Experimental Botany
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    • "We discovered that mucosal HPV16 E7 and HPV11 E7 enter the nucleus via a Ran-dependent pathway, independent of karyopherins/importins, and this pathway is mediated by their zinc-binding domain via hydrophobic interactions with the FG nucleoporin Nup62 (Angeline et al., 2003; Eberhard et al., 2013; Knapp et al., 2009; Piccioli et al., 2010; McKee et al., 2013). Nup62 is located at the central channel of the NPC and forms triple helices with Nup54 that project alternatively up and down from either side of the midplane Nup54-Nup58 ring, and constitute cytoplasmic and nucleoplasmic interaction sites for nuclear import and export complexes (Solmaz et al., 2011). A recent study showed that Flag-HPV8 E7 expressed in transfected human keratinocytes is predominantly localized in the nucleus with some low levels in the cytoplasm (Sperling et al., 2012). "
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    ABSTRACT: We have previously discovered and characterized the nuclear import pathways for the E7 oncoproteins of mucosal alpha genus HPVs, type 16 and 11. Here we investigated the nuclear import of cutaneous beta genus HPV8 E7 protein using confocal microscopy after transfections of HeLa cells with EGFP-8E7 and mutant plasmids and nuclear import assays in digitonin-permeabilized HeLa cells. We determined that HPV8 E7 contains a nuclear localization signal (NLS) within its zinc-binding domain that mediates its nuclear import. Furthermore, we discovered that a mostly hydrophobic patch 65LRLFV69 within the zinc-binding domain is essential for the nuclear import and localization of HPV8 E7 via hydrophobic interactions with the FG nucleoporins Nup62 and Nup153. Substitution of the hydrophobic residues within the 65LRLFV69 patch to alanines, and not R66A mutation, disrupt the interactions between the 8E7 zinc-binding domain and Nup62 and Nup153 and consequently inhibit nuclear import of HPV8 E7.
    Preview · Article · Jan 2014 · Virology
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