TY - JOUR
T1 - Yeast nucleoporins involved in passive nuclear envelope permeability
AU - Shulga, Nataliya
AU - Mosammaparast, Nima
AU - Wozniak, Richard
AU - Goldfarb, David S.
PY - 2000/5/29
Y1 - 2000/5/29
N2 - The vertebrate nuclear pore complex (NPC) harbors an ~ 10-nm diameter diffusion channel that is large enough to admit 50-kD polypeptides. We have analyzed the permeability properties of the Saccharomyces cerevisiae nuclear envelope (NE) using import (NLS) and export (NES) signal-containing green fluorescent protein (GFP) reporters. Compared with wild-type, passive export rates of a classical karyopherin/importin (Kap) Kap60p/Kap95p-targeted NLS- GFP reporter (cNLS-GFP) were significantly faster in nup188-Δ and nup170-Δ cells. Similar results were obtained using two other NLS-GFP reporters, containing either the Kap104p-targeted Nab2p NLS (rgNLS) or the Kap121p- targeted Pho4p NLS (pNLS). Elevated levels of Hsp70 stimulated cNLS-GFP import, but had no effect on the import of rgNLS-GFP. Thus, the role of Hsp70 in NLS-directed import may be NLS- or targeting pathway-specific. Equilibrium sieving limits for the diffusion channel were assessed in vivo using NES-GFP reporters of 36-126 kD and were found to be greater than wild-type in nup188- Δ and nup170-Δ cells. We propose that Nup170p and Nup188p are involved in establishing the functional resting diameter of the NPC's central transport channel.
AB - The vertebrate nuclear pore complex (NPC) harbors an ~ 10-nm diameter diffusion channel that is large enough to admit 50-kD polypeptides. We have analyzed the permeability properties of the Saccharomyces cerevisiae nuclear envelope (NE) using import (NLS) and export (NES) signal-containing green fluorescent protein (GFP) reporters. Compared with wild-type, passive export rates of a classical karyopherin/importin (Kap) Kap60p/Kap95p-targeted NLS- GFP reporter (cNLS-GFP) were significantly faster in nup188-Δ and nup170-Δ cells. Similar results were obtained using two other NLS-GFP reporters, containing either the Kap104p-targeted Nab2p NLS (rgNLS) or the Kap121p- targeted Pho4p NLS (pNLS). Elevated levels of Hsp70 stimulated cNLS-GFP import, but had no effect on the import of rgNLS-GFP. Thus, the role of Hsp70 in NLS-directed import may be NLS- or targeting pathway-specific. Equilibrium sieving limits for the diffusion channel were assessed in vivo using NES-GFP reporters of 36-126 kD and were found to be greater than wild-type in nup188- Δ and nup170-Δ cells. We propose that Nup170p and Nup188p are involved in establishing the functional resting diameter of the NPC's central transport channel.
KW - Diffusion channel
KW - Green fluorescent protein
KW - Import/export signals
KW - Nuclear pore complex
KW - Saccharomyces cerevisiae
UR - http://www.scopus.com/inward/record.url?scp=0034729194&partnerID=8YFLogxK
U2 - 10.1083/jcb.149.5.1027
DO - 10.1083/jcb.149.5.1027
M3 - Article
C2 - 10831607
AN - SCOPUS:0034729194
VL - 149
SP - 1027
EP - 1038
JO - Journal of Cell Biology
JF - Journal of Cell Biology
SN - 0021-9525
IS - 5
ER -