The interaction between Ran and NTF2 is required for cell cycle progression.
The small GTPase Ran is required for the trafficking of macromolecules into and out of the nucleus. Ran also has been implicated in cell cycle control, specifically in mitotic spindle assembly. In interphase cells, Ran is predominately nuclear and thought to be GTP bound, but it is also present in the cytoplasm, probably in the GDP-bound state. Nuclear transport factor 2 (NTF2) has been shown to import RanGDP into the nucleus. Here, we examine the in vivo role of NTF2 in Ran import and the effect that disruption of Ran imported into the nucleus has on the cell cycle. A temperature-sensitive (ts) mutant of Saccharomyces cerevisiae NTF2 that does not bind to Ran is unable to import Ran into the nucleus at the nonpermissive temperature. Moreover, when Ran is inefficiently imported into the nucleus, cells arrest in G(2) in a MAD2 checkpoint-dependent manner. These findings demonstrate that NTF2 is required to transport Ran into the nucleus in vivo. Furthermore, we present data that suggest that depletion of nuclear Ran triggers a spindle-assembly checkpoint-dependent cell cycle arrest.
Quimby
B B
BB
Department of Biochemistry, Emory University School of Medicine, Atlanta, GA 30322, USA.
Wilson
C A
CA
Corbett
A H
AH
D000818:Animals; D001692:Biological Transport; D002135:Calcium-Binding Proteins / Q000187:drug effects / Q000235:genetics / Q000502:physiology; D002352:Carrier Proteins / Q000187:drug effects / Q000235:genetics / Q000502:physiology*; D002453:Cell Cycle; D018797:Cell Cycle Proteins; D005656:Fungal Proteins / Q000187:drug effects / Q000235:genetics / Q000502:physiology; D064246:Mad2 Proteins; D008856:Microscopy, Fluorescence; D008870:Microtubules / Q000187:drug effects / Q000378:metabolism; D009154:Mutation; D015739:Nocodazole / Q000494:pharmacology; D009687:Nuclear Proteins / Q000187:drug effects / Q000235:genetics / Q000502:physiology*; D029543:Nucleocytoplasmic Transport Proteins; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000166:cytology / Q000187:drug effects / Q000502:physiology; D029701:Saccharomyces cerevisiae Proteins; D013696:Temperature; D014170:Transformation, Genetic; D014404:Tubulin / Q000378:metabolism; D050257:Tubulin Modulators; D020931:ran GTP-Binding Protein / Q000235:genetics / Q000378:metabolism* / Q000502:physiology*
D002135:Calcium-Binding Proteins; D002352:Carrier Proteins; D018797:Cell Cycle Proteins; D005656:Fungal Proteins; C577695:MAD2 protein, S cerevisiae; D064246:Mad2 Proteins; D009687:Nuclear Proteins; D029543:Nucleocytoplasmic Transport Proteins; D011993:Recombinant Fusion Proteins; D029701:Saccharomyces cerevisiae Proteins; D014404:Tubulin; D050257:Tubulin Modulators; D020931:ran GTP-Binding Protein; D015739:Nocodazole