Toward the molecular dissection of protein import into nuclei

Current Opinion in Cell Biology

Volumn 8, Issue 3, 1996, Pages 397-406

  Panté, Nelly ^a   Aebi, Ueli ^a,b  

^a UNIVERSITY OF BASEL   (Switzerland)

^b JOHNS HOPKINS UNIVERSITY SCHOOL OF MEDICINE   (United States)

Author keywords

[No Author keywords available]

Indexed keywords

GUANOSINE TRIPHOSPHATASE; KARYOPHERIN; MEMBRANE PROTEIN; NUCLEOPORIN; PROTEIN; RIBONUCLEOPROTEIN; RNA;

AMINO ACID SEQUENCE; CELL NUCLEUS; CELL NUCLEUS MEMBRANE; MEMBRANE TRANSPORT; PRIORITY JOURNAL; PROTEIN TRANSPORT; REVIEW; RNA TRANSPORT;

EID: 0029952023     PISSN: 09550674     EISSN: None     Source Type: Journal    
DOI: 10.1016/S0955-0674(96)80016-0     Document Type: Article

References (65)

1. Panté N, Aebi U: Towards understanding the 3-D structure of the nuclear pore complex at the molecular level. Curr Opin Struct Biol 1994, 4:187-196.
2. Panté N, Aebi U: Toward a molecular understanding of the structure and function of the nuclear pore complex. Int Rev Cytol 1995, 162B:225-255.
3. Adam SA, Sterne-Marr R, Gerace L: Nuclear protein import in permeabilized mammalian cells requires soluble cytoplasmic factors. J Cell Biol 1990, 111:807-816.
4. Adam SA, Gerace L: Cytosolic proteins that specifically bind nuclear localization signals are receptors for nuclear import. Cell 1991, 66:837-847.
5. Shi Y, Thomas JO: The transport of proteins into the nucleus requires the 70-kilodalton heat shock protein or its cytoplasmic cognate. Mol Cell Biol 1992, 12:2186-2192.
6. •]).
7. •]). On the basis of ligand blot essays, it is suggested that the amino-terminal peptide repeat domain of Nup98 represents a karyopherin-mediated docking site for import ligands.
8. •]).
9. Panté N, Aebi U: Toward the molecular details of the nuclear pore complex. J Struct Biol 1994, 113:179-189.
10. Bastos R, Panté N, Burke B: Nuclear pore complex proteins. Int Rev Cyt 1995, 162B:257-302.
11. Boulikas T: Nuclear localization signals (NLS). Crit Rev Eukar Gene Expr 1993, 3:193-227.
12. Gerace L: Molecular trafficking across the nuclear pore complex. Curr Opin Cell Biol 1992, 4:637-645.
13. Duverger E, Pellerin-Mendes C, Mayer R, Roche A-C, Monsigny M: Nuclear import of glycoconjugates is distinct from the classical NLS pathway. J Cell Sci 1995, 108:1325-1332.
14. Melchior F, Gerace G: Mechanism of nuclear protein import Curr Opin Cell Biol 1995, 7:310-318.
15. Moore MS, Blobel G: Purification of a Ran-interacting protein that is required for protein import into the nucleus. Proc Natl Acad Sci USA 1994, 91:10212-10216.
16. 2 subunit binds nuclear localization signal and β subunit interacts with peptide repeat-containing nucleoporins. Proc Natl Acad Sci USA 1995, 92:6532-6536. Describes the functional characterization of Rch1, one of the human homologs of importin α. The localization of importin a, importin β, Ran and NTF2 at 30 minutes after their addition to digitonin-permeabilized, cytosol-depleted cells demonstrated that importin α, Ran and NTF2 enter the nucleus concomitantly with the NLS protein, whereas importin β is retained at the NE.
17. Yang J, DeFranco DB: Differential roles of heat shock protein 70 in the in vitro nuclear import of glucocorticoid receptor and simian virus 40 large tumor antigen. Mol Cell Biol 1994, 14:5088-5098.
18. Görlich D, Prehn S, Laskey R, Hartmann E: Isolation of a protein that is essential for the first step of nuclear protein import Cell 1994, 79:767-778. Describes the first cytosolic transport factor that was molecularly characterized. The gene encoding importin a, the Xenopus homolog of the mammalian NLS receptor [4], was isolated, cloned and sequenced. Both the isolated and the recombinant protein were able to dock NLS proteins to the NE of digitonin-permeabilized HeLa cells.
19. Chi NC, Adam EJH, Adam SA: Sequence and characterization of cytoplasmic nuclear protein import factor p97. J Cell Biol 1995, 130:265-274. The gene encoding the cytosolic transport factor p97, a protein previously identified and purified from bovine erythrocytes [30], was cloned, sequenced and identified as the mammalian homolog of Xenopus importin β. By immunofluorescence microscopy, p97 was localized to the cytoplasm and the NE of mammalian cells. An anti-p97 antibody inhibited the import of NLS proteins into nuclei of digitonin-permeabilized, cytosol-depleted cells, but did not inhibit the binding of the import ligand complex to the NPC.
20. Yano R, Oakes M, Yamaghishi M, Dodd JA, Nomura M: Cloning and characterization of SRP1, a suppressor of temperature-sensitive RNA polymerase I mutations, in Saccharomyces cerevisiae. Mol Cell Biol 1992, 12:5640-5641.
21. Cortes P, Ye Z, Baltimore D: RAG-1 interacts with the repeated amino acid motif of the human homologue of the yeast protein SRP1. Proc Natl Acad Sci USA 1994, 91:7633-7637.
22. Cuomo CA, Kirch SA, Gyuris J, Brent R, Oettinger MA: Rch1, a protein that specifically interacts with the RAG-1 recombination-activating protein. Proc Natl Acad Sci USA 1994, 91:6156-6160.
23. O'Neill RE, Palese P: NPI-1, the human homolog of SRP-1, interacts with influenza virus nucleoprotein. Virology 1995, 206:116-125.
24. Weis K, Mattaj IW, Lamond AI: Identification of hSRP1α as a functional receptor for nuclear localization sequences. Science 1995, 268:1049-1053. hSRP1α, a human homolog of importin α, was found in a yeast two-hybrid screen. A 90 kDa protein (importin β) was co-immunoprecipitated with hSRP1α. It was demonstrated by immunoprecipitation that hSRP1α can directly associate with NLSs.
25. Küssel P, Frasch M: Pendulin, a Drosophila protein with cell cycle-dependent nuclear localization, is required for normal cell proliferation. J Cell Biol 1995, 129:1491-1507.
26. Török I, Strand D, Schmitt R, Tick G, Török T, Kiss I, Mechler M: The overgrown hematopoietic organs-31 tumor suppressor gene of Drosophila encodes an importin-like protein accumulating in the nucleus at the onset of mitosis. J Cell Biol 1995, 129:1473-1489.
27. Peifer M, Berg S, Reynolds AB: A repeating amino acid motif shared by proteins with diverse cellular roles. Cell 1994, 76:789-791.
28. •]). On the basis of results obtained from the cytoplasmic injection of antibodies raised against recombinant m-importin, evidence has been provided that m-importin is involved in nuclear protein import through association of m-importin with the NLS of the import ligand prior to NPC binding.
29. Görlich D, Vogel F, Mills AD, Hartmann E, Laskey R: Distinct functions for the two importin subunits in nuclear protein import. Nature 1995, 377:246-248. Detection of the NLS protein, importin a or importin β at 30 minutes after their addition to digitonin-permeabilized HeLa cells demonstrated that importin α enters the nucleus concomitantly with the NLS protein, whereas importin β is confined to the NE. By using immunogold electron microscopy, importin β was found to be associated with both the cytoplasmic and the nuclear peripheries of the NPC in rat liver cryosections.
30. Adam EJH, Adam SA: Identification of cytosolic factors required for nuclear localization sequence-mediated binding to the nuclear envelope. J Cell Biol 1994, 125:547-555.
31. Enenkel C, Blobel G, Rexach M: Identification of a yeast karyopherin heterodimer that targets import substrate to mammalian nuclear pore complexes. J Biol Chem 1995, 270:16499-16502.
32. Görlich D, Kostka S, Kraft R, Dingwall C, Laskey R, Hartmann E: Two different subunits of importin cooperate to recognize nuclear localization signals and bind them to the nuclear envelope. Curr Biol 1995, 5:383-392.
33. •]).
34. •]).
35. Belanger KD, Kenna MA, Wei S, Davis L: Genetic and physical interactions between Srplp and nuclear pore complex proteins NUP1p and NUP2p. J Cell Biol 1994, 126:619-630.
36. Moore MS, Blobel G: The GTP-binding protein Ran/TC4 is required for protein import into the nucleus. Nature 1993, 365:661-663.
37. Melchior F, Paschal B, Evans J, Gerace L: Inhibition of nuclear protein import by nonhydrolyzable analogues of GTP and identification of the small GTPase Ran/TC4 as an essential transport factor. J Cell Biol 1993, 123:1649-1659.
38. Paschal BM, Gerace L: Identification of NTF2, a cytosolic factor for nuclear import that interacts with nuclear pore complex protein p62. J Cell Biol 1995, 129:925-937. Describes the purification and cloning of the transport factor NTF2, from HeLa cell cytosol, via interaction with the nucleoporin p62.
39. Dasso M: RCC1 in the cell cycle: the regulator of chromosome condensation takes new roles. Trends Biochem Sci 1993, 18:96-101.
40. Bischoff FR, Klebe C, Kretschmer J, Wittinghofer A, Ponstingl H: RanGAP1 induces GTPase activity of nuclear Ras-related Ran. Proc Natl Acad Sci USA 1994, 91:2587-2591.
41. Becker J, Melchior F, Gerke V, Bischoff FR, Ponstingl H, Wittinghofer A: RNA1 encodes a GTPase-activating protein specific for Gsp1p, the Ran/TC4 homologue of Saccharomyces cerevisiae. J Biol Chem 1995, 270:11860-11865.
42. Bischoff FR, Krebber H, Kempf T, Hermes I, Ponstingl H: Human RanGTPase-activating protein RanGAP1 is a homologue of yeast Rna1p involved In mRNA processing and transport. Proc Natl Acad Sci USA 1995, 92:1749-1753.
43. Corbett A, Koepp DM, Schlenstedt G, Lee MS, Hopper AK, Silver P: Rna1p, a Ran/TC4 GTPase activating protein, is required for nuclear import. J Cell Biol 1995, 130:1017-1026.
44. Bischoff FR, Krebber H, Smirnova E, Dong W, Ponstingl H: Co-activation of RanGTPase and inhibition of GTP dissociation by Ran-GTP binding protein RanBP1. EMBO J 1995, 14:705-715.
45. +RNA in the cytoplasm. Proc Natl Acad Sci USA 1995, 92:225-229.
46. Tachibana T, Imamoto N, Seino H, Nishimoto T, Yoneda Y: Loss of RCC1 leads to suppression of nuclear protein import in living cells. Biol Chem 1994, 269:24542-24545.
47. Schlenstedt G, Wong DH, Koepp DM, Silver P: Mutants in a yeast Ran binding protein are defective in nuclear transport. EMBO J 1995, 14:5367-5378.
48. ••]).
49. •]). By using immuno-electron microscopy it is shown that RanBP2 exhibits epitopes at the cytoplasmic filaments of the NPC. The finding that the nuclear import of NLS proteins is inhibited by an antibody directed against RanBP2 suggests that this giant nucleoporin plays a role in NPC-mediated nucleocytoplasmic transport.
50. ••]). On the basis of these findings, it is proposed that RanBP2 is likely to constitute the Ran-GTP-binding site identified at the cytoplasmic periphery of the NPC, thus supporting a model in which initial import ligand binding to the NPC occurs at or near RanBP2, and hydrolysis of GTP by Ran at this site serves to commit the import ligand complex to the nuclear import pathway.
51. Guan T, Müller S, Kleir G, Panté N, Blevitt JM, Häner M, Paschal B, Aebi U, Gerace L: Structural analysis of the p62 complex, an assembly of O-linked glycoproteins that localizes near the central gated channel of the nuclear pore complex. Mol Biol Cell 1995, 6:1591-1603. The p62 complex, which interacts with cytosolic transport factors and which represents part of the nucleocytoplasmic transport machinery of the NPC, has been purified from rat liver nuclei. It consists of four distinct O-linked glycoproteins (p62, p58, p54 and p45) in an equimolar complex which has a mass of -234 kDa and a pronounced tendency to oligomerize into larger particles. By electron microscopy it appears as a donut-shaped particle with a diameter of ∼15 nm.
52. Jarmolowski A, Boelens WC, Izaurralde E, Mattaj IW: Nuclear export of different classes of RNA is mediated by specific factors. J Cell Biol. 1994, 124:627-635.
53. Izaurralde E, Mattaj IW: RNA export. Cell 1995, 81:153-159.
54. Izaurralde E, Lewis J, Gamberi C, Jarmolowski A, McGuigan C, Mattaj IW: A cap-binding protein complex mediating U snRNA export. Nature 1995, 376:709-712. Evidence is provided for a role of the nuclear cap binding protein complex (which is composed of the two CBPs CBP80 and CBP20) in U-rich snRNA nuclear export. Microinjection of an anti-CBP20 antibody into Xenopus oocytes results in an inhibition of nuclear export of U snRNAs.
55. Fisher U, Meyer S, Teufel M, Heckel C, Lührmann R, Rautmann G: Evidence that HIV-1 Rev directly promotes the nuclear export of unspliced RNA. EMBO J 1994, 13:4105-4112.
56. ••]. By site-directed mutagenesis it was shown that three of the four leucine residues and an isoleucine are important for nuclear export.
57. Fischer U, Huber J, Boelens WC, Mattaj IW, Lührmann R: The HIV-1 Rev activation domain is a nuclear export signal that accesses an export pathway used by specific cellular RNAs. Cell 1995, 82:475-483. The nuclear export activity of Rev was identified within a 9 amino acid long leucine-rich peptide of the activation domain of Rev. Bovine serum albumin (BSA) conjugated with the NES of Rev (termed BSA-R) inhibited Rev-mediated nuclear export of RNAs containing the Rev response element. By co-injection of BSA-R with different RNAs into Xenopus oocytes, it was shown that BSA-R competes for the export of 5S rRNA and U snRNAs (but not for the export of mRNAs, tRNAs and ribosomal subunits). Hence it was concluded that the export pathway of Rev is also used by other RNAs.
58. Michael WM, Choi M, Dreyfuss G: A nuclear export signal in hnRNP A1: a signal-mediated, temperature-dependent nuclear protein export pathway. Cell 1995, 83:415-422. The signal in the heterogeneous nuclear RNP (hnRNP) protein A1 that promotes nuclear export of this protein was identified within a 38 amino acid long domain (termed M9); this domain also contains the unique NLS of A1. By site-directed mutagenesis it was shown that specific amino acids within the M9 domain of the A1 protein are critical for the nuclear export of A1.
59. Gerace L: Nuclear export signals and the fast track to the cytoplasm. Cell 1995, 82:341-344.
60. Moroianu J, Blobel G: Protein export from the nucleus requires the GTPase Ran and GTP hydrolysis. Proc Natl Acad Sci USA 1995, 92:4318-4322.
61. •]) that is a candidate for an NES receptor was identified in a yeast two-hybrid screen. This protein functionally interacts with the Rev activation domain when Rev is bound to its RNA target.
62. •], termed Rab, was identified by the authors of this paper. This protein was present in nuclear extracts of HeLa cells, and was localized at the NE and within the nucleoplasm of HeLa cells by immunofluoresence microscopy.
63. •], termed Rip1, was identified in a yeast two-hybrid screen, and it was localized to the NE of yeast cells by immunofluoresence microscopy. Both overexpression of the gene encoding this protein and gene disruption reduced the activity of Rev in transactivation assays.
64. Panté N, Aebi U: Exploring nuclear pore complex structure and function in molecular detail. J Cell Sci 1995, 108(suppl 19):1-11.
65. Belhumeur P, Lee A, Tam R, DiPaolo T, Fortin N, Clark MW: GSP1 and GSP2, genetic supressors of the prp20-1 mutant in Saccharomyces cerevisiae: GTP-binding proteins involved in the maintenance of nuclear organization. Mol Cell Biol 1993, 13:2152-2161.