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The cytoplasmic filaments of the nuclear pore complex are dispensable for selective nuclear protein import

Walther, TC; Pickersgill, HS; Cordes, VC; Goldberg, MW; Allen, TD; Mattaj, IW; Fornerod, M

The cytoplasmic filaments of the nuclear pore complex are dispensable for selective nuclear protein import Thumbnail


Authors

TC Walther

HS Pickersgill

VC Cordes

TD Allen

IW Mattaj

M Fornerod



Abstract

The nuclear pore complex (NPC) mediates bidirectional macromolecular traffic between the nucleus and cytoplasm in eukaryotic cells. Eight filaments project from the NPC into the cytoplasm and are proposed to function in nuclear import. We investigated the localization and function of two nucleoporins on the cytoplasmic face of the NPC, CAN/Nup214 and RanBP2/Nup358. Consistent with previous data, RanBP2 was localized at the cytoplasmic filaments. In contrast, CAN was localized near the cytoplasmic coaxial ring. Unexpectedly, extensive blocking of RanBP2 with gold-conjugated antibodies failed to inhibit nuclear import. Therefore, RanBP2-deficient NPCs were generated by in vitro nuclear assembly in RanBP2-depleted Xenopus egg extracts. NPCs were formed that lacked cytoplasmic filaments, but that retained CAN. These nuclei efficiently imported nuclear localization sequence (NLS) or M9 substrates. NPCs lacking CAN retained RanBP2 and cytoplasmic filaments, and showed a minor NLS import defect. NPCs deficient in both CAN and RanBP2 displayed no cytoplasmic filaments and had a strikingly immature cytoplasmic appearance. However, they showed only a slight reduction in NLS-mediated import, no change in M9-mediated import, and were normal in growth and DNA replication. We conclude that RanBP2 is the major nucleoporin component of the cytoplasmic filaments of the NPC, and that these filaments do not have an essential role in importin /ß– or transportin-dependent import.

Citation

Walther, T., Pickersgill, H., Cordes, V., Goldberg, M., Allen, T., Mattaj, I., & Fornerod, M. (2002). The cytoplasmic filaments of the nuclear pore complex are dispensable for selective nuclear protein import. Journal of Cell Biology, 158(1), 63-77. https://doi.org/10.1083/jcb.200202088

Journal Article Type Article
Publication Date Jul 1, 2002
Deposit Date Aug 29, 2008
Publicly Available Date Aug 29, 2008
Journal Journal of Cell Biology
Print ISSN 0021-9525
Electronic ISSN 1540-8140
Publisher Rockefeller University Press
Peer Reviewed Peer Reviewed
Volume 158
Issue 1
Pages 63-77
DOI https://doi.org/10.1083/jcb.200202088
Keywords Nuclear pore complex, Nuclear import, Nuclear localization signal, RANBP2/NUP358, CAN/NUP214scanning electron-microscopy, Gtpase-activating protein, Binding-protein, Field-emission, Nucleocytoplasmic transport, DNA-replication, Karyophilic proteins, Annul

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