title: Visualization of PML nuclear import complexes reveals FG-repeat nucleoporins at cargo retrieval sites.
abstract: Selective nuclear import in eukaryotic cells involves sequential interactions between nuclear import receptors and phenylalanine-glycine (FG)-repeat nucleoporins. Traditionally, binding of cargoes to import receptors is perceived as a nuclear pore complex independent event, while interactions between import complexes and nucleoporins are thought to take place at the nuclear pores. However, studies have shown that nucleoporins are mobile and not static within the nuclear pores, suggesting that they may become engaged in nuclear import before nuclear pore entry. Here we have studied post-mitotic nuclear import of the tumor suppressor protein PML. Since this protein forms nuclear compartments called PML bodies that persist during mitosis, the assembly of putative PML import complexes can be visualized on the surface of these protein aggregates as the cell progress from an import inactive state in mitosis to an import active state in G1. We show that these post-mitotic cytoplasmic PML bodies incorporate a multitude of peripheral nucleoporins, but not scaffold or nuclear basket nucleoporins, in a manner that depends on FG-repeats, the KPNB1 import receptor, and the PML nuclear localization signal. The study suggests that nucleoporins have the ability to target certain nuclear cargo proteins in a nuclear pore-uncoupled state, before nuclear pore entry.
authors.affiliation: a Department of Medical Biochemistry , Oslo University Hospital , Oslo , Norway.|b Institute of Clinical Medicine , University of Oslo , Oslo , Norway.
authors.forename: Anna
authors.initials: A
authors.lastname: Lång
authors.affiliation: a Department of Medical Biochemistry , Oslo University Hospital , Oslo , Norway.
authors.forename: Jens
authors.initials: J
authors.lastname: Eriksson
authors.affiliation: c Department of Molecular Cell Biology, Institute for Cancer Research and Centre for Cancer Biomedicine , Oslo University Hospital , Oslo , Norway.
authors.forename: Kay Oliver
authors.initials: KO
authors.lastname: Schink
authors.affiliation: a Department of Medical Biochemistry , Oslo University Hospital , Oslo , Norway.
authors.forename: Emma
authors.initials: E
authors.lastname: Lång
authors.affiliation: a Department of Medical Biochemistry , Oslo University Hospital , Oslo , Norway.
authors.forename: Pernille
authors.initials: P
authors.lastname: Blicher
authors.affiliation: a Department of Medical Biochemistry , Oslo University Hospital , Oslo , Norway.
authors.forename: Anna
authors.initials: A
authors.lastname: Połeć
authors.affiliation: c Department of Molecular Cell Biology, Institute for Cancer Research and Centre for Cancer Biomedicine , Oslo University Hospital , Oslo , Norway.
authors.forename: Andreas
authors.initials: A
authors.lastname: Brech
authors.affiliation: a Department of Medical Biochemistry , Oslo University Hospital , Oslo , Norway.
authors.forename: Bjørn
authors.initials: B
authors.lastname: Dalhus
authors.affiliation: a Department of Medical Biochemistry , Oslo University Hospital , Oslo , Norway.
authors.forename: Stig Ove
authors.initials: SO
authors.lastname: Bøe
mesh_terms: D021581:Active Transport, Cell Nucleus / Q000502:physiology; D015153:Blotting, Western; D002453:Cell Cycle; D005998:Glycine / Q000737:chemistry* / Q000378:metabolism; D008938:Mitosis; D008954:Models, Biological; D028861:Nuclear Pore Complex Proteins / Q000737:chemistry* / Q000378:metabolism; D010649:Phenylalanine / Q000737:chemistry* / Q000378:metabolism
chemical_list: D028861:Nuclear Pore Complex Proteins; D010649:Phenylalanine; D005998:Glycine
keywords: FG-repeats; KPNB1; PML; PML bodies; nuclear import; nuclear pore complex; nucleoporins