The Journal of Cell Biology, Vol 123, 1345-1354, Copyright © 1993 by The Rockefeller University Press

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Nup180, a novel nuclear pore complex protein localizing to the cytoplasmic ring and associated fibrils

N Wilken, U Kossner, JL Senecal, U Scheer and MC Dabauvalle
Department of Cell and Developmental Biology, Theodor-Boveri-Institute, University of Wurzburg, Germany.

Using an autoimmune serum from a patient with overlap connective tissue disease we have identified by biochemical and immunocytochemical approaches an evolutionarily conserved nuclear pore complex (NPC) protein with an estimated molecular mass of 180 kD and an isoelectric point of approximately 6.2 which we have designated as nup180. Extraction of isolated nuclear envelopes with 2 M urea and chromatography of the solubilized proteins on WGA-Sepharose demonstrated that nup180 is a peripheral membrane protein and does not react with WGA. Affinity-purified antibodies yielded a punctate immunofluorescent pattern of the nuclear surface of mammalian cells and stained brightly the nuclear envelope of cryosectioned Xenopus oocytes. Nuclei reconstituted in vitro in Xenopus egg extract were also stained in the characteristic punctate fashion. Immunogold EM localized nup180 exclusively to the cytoplasmic ring of NPCs and short fibers emanating therefrom into the cytoplasm. Antibodies to nup180 did not inhibit nuclear protein transport in vivo nor in vitro. Despite the apparent lack of involvement in NPC assembly or nucleocytoplasmic transport processes, the conservation of nup180 across species and its exclusive association with the NPC cytoplasmic ring suggests an important, though currently undefined function for this novel NPC protein.
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This article has been cited by other articles:

• Naim, B., Brumfeld, V., Kapon, R., Kiss, V., Nevo, R., Reich, Z. (2007). Passive and Facilitated Transport in Nuclear Pore Complexes Is Largely Uncoupled. J. Biol. Chem. 282: 3881-3888 [Abstract] [Full Text]  
• Ewald, A, Kossner, U, Scheer, U, Dabauvalle, M. (1996). A biochemical and immunological comparison of nuclear and cytoplasmic pore complexes. J. Cell Sci. 109: 1813-1824 [Abstract]  
• Blobel, G. (1995). Unidirectional and Bidirectional Protein Traffic across Membranes. Cold Spring Harb Symp Quant Biol 60: 1-10 [Abstract]  

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