Journal of Cell Science, Vol 110, Issue 24 3065-3070, Copyright © 1997 by Company of Biologists

JOURNAL ARTICLES

The location of the transport gate in the nuclear pore complex

CM Feldherr and D Akin
Department of Anatomy and Cell Biology, University of Florida, College of Medicine, Gainesville, FL 32610, USA.

Signal-mediated nuclear transport is a gated process that occurs through a central transporter element located within the pore complex. The purpose of this investigation was to identify the region of the transporter that functions as the gate; i.e. the region that restricts passive diffusion of macromolecules through the pores. To accomplish this, small gold particles coated with polyethylene glycol (PEG; total particle diameter 40-70 A) or large PEG-particles (total diameter 110-270 A) were microinjected into the cytoplasm or nucleoplasm of Xenopus oocytes. Since PEG does not contain either nuclear import or export signals, it is assumed that the particles distribute by simple diffusion. The cells were fixed after 5 or 30 minutes and subsequently examined using TEM. The distribution of the particles located adjacent to and within the pore complexes was then mapped. The results obtained at both 5 and 30 minutes after cytoplasmic injections of small gold were basically the same. The particles readily entered the transporter but, on the average, were approximately 11 times more concentrated in the cytoplasmic half of this structure. The opposite distribution was observed following nuclear injections, i.e. the particles that were located in the transporter were approximately 7 times more numerous in the nuclear half. Our data indicate that there is a single transport gate located in the central domain of the transporter that restricts passive diffusion. The large particles that were injected into the cytoplasm migrated to the surface of the pore complex, but entered the transporter less frequently than small gold. Interestingly, the diffusion of large PEG-particles to the surface of the pores following nuclear injection was greatly restricted; however, this was not the case for similar size particles that were coated with protein containing nuclear export signals (NES). The latter results suggest that the NES is not only required for translocation, but also for migration within the nucleoplasm.

This article has been cited by other articles:

				B. Naim, V. Brumfeld, R. Kapon, V. Kiss, R. Nevo, and Z. Reich Passive and Facilitated Transport in Nuclear Pore Complexes Is Largely Uncoupled J. Biol. Chem., February 9, 2007; 282(6): 3881 - 3888. [Abstract] [Full Text] [PDF]

				A. L. Miller, M. Suntharalingam, S. L. Johnson, A. Audhya, S. D. Emr, and S. R. Wente Cytoplasmic Inositol Hexakisphosphate Production Is Sufficient for Mediating the Gle1-mRNA Export Pathway J. Biol. Chem., December 3, 2004; 279(49): 51022 - 51032. [Abstract] [Full Text] [PDF]

				E. Kiseleva, S. P. Drummond, M. W. Goldberg, S. A. Rutherford, T. D. Allen, and K. L. Wilson Actin- and protein-4.1-containing filaments link nuclear pore complexes to subnuclear organelles in Xenopus oocyte nuclei J. Cell Sci., May 15, 2004; 117(12): 2481 - 2490. [Abstract] [Full Text] [PDF]

				G. Liu, D. Li, M. K. Pasumarthy, T. H. Kowalczyk, C. R. Gedeon, S. L. Hyatt, J. M. Payne, T. J. Miller, P. Brunovskis, T. L. Fink, et al. Nanoparticles of Compacted DNA Transfect Postmitotic Cells J. Biol. Chem., August 29, 2003; 278(35): 32578 - 32586. [Abstract] [Full Text] [PDF]

				J. Bednenko, G. Cingolani, and L. Gerace Importin {beta} contains a COOH-terminal nucleoporin binding region important for nuclear transport J. Cell Biol., August 4, 2003; 162(3): 391 - 401. [Abstract] [Full Text] [PDF]

				N. Shulga and D. S. Goldfarb Binding Dynamics of Structural Nucleoporins Govern Nuclear Pore Complex Permeability and May Mediate Channel Gating Mol. Cell. Biol., January 15, 2003; 23(2): 534 - 542. [Abstract] [Full Text] [PDF]

				S. K. Lyman, T. Guan, J. Bednenko, H. Wodrich, and L. Gerace Influence of cargo size on Ran and energy requirements for nuclear protein import J. Cell Biol., October 14, 2002; 159(1): 55 - 67. [Abstract] [Full Text] [PDF]

				C. M. Feldherr, D. Akin, and R. J. Cohen Regulation of functional nuclear pore size in fibroblasts J. Cell Sci., March 14, 2002; 114(24): 4621 - 4627. [Abstract] [Full Text] [PDF]

				I. G. Macara Transport into and out of the Nucleus Microbiol. Mol. Biol. Rev., December 1, 2001; 65(4): 570 - 594. [Abstract] [Full Text] [PDF]

				N. Shulga, N. Mosammaparast, R. Wozniak, and D. S. Goldfarb Yeast Nucleoporins Involved in Passive Nuclear Envelope Permeability J. Cell Biol., May 29, 2000; 149(5): 1027 - 1038. [Abstract] [Full Text] [PDF]

				M. P. Rout, J. D. Aitchison, A. Suprapto, K. Hjertaas, Y. Zhao, and B. T. Chait The Yeast Nuclear Pore Complex: Composition, Architecture, and Transport Mechanism J. Cell Biol., February 21, 2000; 148(4): 635 - 652. [Abstract] [Full Text] [PDF]

				T. Allen, J. Cronshaw, S Bagley, E Kiseleva, and M. Goldberg The nuclear pore complex: mediator of translocation between nucleus and cytoplasm J. Cell Sci., January 5, 2000; 113(10): 1651 - 1659. [Abstract] [PDF]

				F. Iborra, D. Jackson, and P. Cook The path of RNA through nuclear pores: apparent entry from the sides into specialized pores J. Cell Sci., January 1, 2000; 113(2): 291 - 302. [Abstract] [PDF]

				N. R. Yaseen and G. Blobel GTP Hydrolysis Links Initiation and Termination of Nuclear Import on the Nucleoporin Nup358 J. Biol. Chem., September 10, 1999; 274(37): 26493 - 26502. [Abstract] [Full Text] [PDF]

				B. M.A. Fontoura, G. Blobel, and M. J. Matunis A Conserved Biogenesis Pathway for Nucleoporins: Proteolytic Processing of a 186-Kilodalton Precursor Generates Nup98 and the Novel Nucleoporin, Nup96 J. Cell Biol., March 22, 1999; 144(6): 1097 - 1112. [Abstract] [Full Text] [PDF]

				A Maizel, O Bensaude, A Prochiantz, and A Joliot A short region of its homeodomain is necessary for engrailed nuclear export and secretion Development, January 6, 1999; 126(14): 3183 - 3190. [Abstract] [PDF]