title: Exogenously injected nuclear import factor p10/NTF2 inhibits signal-mediated nuclear import and export of proteins in living cells.
abstract: p10/NTF2 is a cytosolic factor which is required for the translocation step in nuclear protein import in an in vitro assay with digitonin-permeabilized cells. To study the functional roles of p10/NTF2 on protein transport between the nucleus and cytoplasm in living cells, recombinant p10/NTF2 was micro-injected into cultured mammalian cells. Cytoplasmically injected p10/NTF2 strongly inhibited the nuclear import of co-injected NLS-containing substrates in a dose-dependent manner but had no effect on the diffusive import of small non-nuclear proteins. Moreover, when injected into the cell nucleus, p10/NTF2 inhibited the nuclear export of NES-containing substrates. The results suggest that the nuclear import factor p10/NTF2 may also be involved in the nuclear export of proteins and that the protein transport efficiency between the nucleus and cytoplasm may be regulated by the intracellular level of p10/NTF2.
authors.affiliation: Department of Anatomy and Cell Biology, Osaka University Medical School, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Tachibana
authors.forename: M
authors.initials: M
authors.lastname: Hieda
authors.forename: T
authors.initials: T
authors.lastname: Sekimoto
authors.forename: Y
authors.initials: Y
authors.lastname: Yoneda
mesh_terms: D000818:Animals; D001692:Biological Transport; D002352:Carrier Proteins / Q000494:pharmacology* / Q000502:physiology; D002460:Cell Line; D002467:Cell Nucleus / Q000378:metabolism*; D003593:Cytoplasm / Q000378:metabolism*; D004058:Diffusion; D004285:Dogs; D006801:Humans; D008845:Microinjections; D009685:Nuclear Envelope / Q000378:metabolism; D009687:Nuclear Proteins / Q000378:metabolism* / Q000494:pharmacology* / Q000502:physiology; D029543:Nucleocytoplasmic Transport Proteins; D021382:Protein Sorting Signals / Q000378:metabolism; D011506:Proteins / Q000378:metabolism*; D011994:Recombinant Proteins / Q000494:pharmacology
chemical_list: D002352:Carrier Proteins; D009687:Nuclear Proteins; D029543:Nucleocytoplasmic Transport Proteins; D021382:Protein Sorting Signals; D011506:Proteins; D011994:Recombinant Proteins