Abstract
The import of proteins into the nucleus is a vital process that is mediated by proteins which specifically recognize nuclear localization signals (NLSs). These factors have not been identified in plants. Previously, we demonstrated that higher plants possess a low-affinity binding site at the nuclear pore that specifically binds to several classes of functional NLSs. By the use of crosslinking reagents and a radiolabeled peptide to the bipartite NLS from the endogenous plant transcription factor Opaque2, two NLS binding proteins (NBPs) of 50-60 kDa and at least two NBPs of 30-40 kDa were identified. Competition studies indicated that labeling was specific for the functional NLS but not a mutant NLS impaired in vivo or a peptide unrelated to NLSs. Also, the apparent dissociation constant (100-300 microM) for labeling was similar to that of the binding site. Proteins of similar mass were labeled with two different crosslinking reagents, and concentration and time studies indicated that these NBPs were distinct proteins and not aggregates. Treatment with salt, detergent, or urea before or during NLS binding demonstrated that the properties of the binding site and the NBPs were identical. This tight correlation strongly indicates that some or all of the NBPs constitute the nuclear pore binding site. Overall, our results indicate that some components of NLS recognition are located at the nuclear pores in higher plants.
Full text
PDFImages in this article
Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- Adam E. J., Adam S. A. Identification of cytosolic factors required for nuclear location sequence-mediated binding to the nuclear envelope. J Cell Biol. 1994 May;125(3):547–555. doi: 10.1083/jcb.125.3.547. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Adam S. A., Gerace L. Cytosolic proteins that specifically bind nuclear location signals are receptors for nuclear import. Cell. 1991 Sep 6;66(5):837–847. doi: 10.1016/0092-8674(91)90431-w. [DOI] [PubMed] [Google Scholar]
- Adam S. A., Lobl T. J., Mitchell M. A., Gerace L. Identification of specific binding proteins for a nuclear location sequence. Nature. 1989 Jan 19;337(6204):276–279. doi: 10.1038/337276a0. [DOI] [PubMed] [Google Scholar]
- Agutter P. S., Prochnow D. Nucleocytoplasmic transport. Biochem J. 1994 Jun 15;300(Pt 3):609–618. doi: 10.1042/bj3000609. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Bossie M. A., DeHoratius C., Barcelo G., Silver P. A mutant nuclear protein with similarity to RNA binding proteins interferes with nuclear import in yeast. Mol Biol Cell. 1992 Aug;3(8):875–893. doi: 10.1091/mbc.3.8.875. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Carrington J. C., Freed D. D., Leinicke A. J. Bipartite signal sequence mediates nuclear translocation of the plant potyviral NIa protein. Plant Cell. 1991 Sep;3(9):953–962. doi: 10.1105/tpc.3.9.953. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Citovsky V., Zambryski P. Transport of nucleic acids through membrane channels: snaking through small holes. Annu Rev Microbiol. 1993;47:167–197. doi: 10.1146/annurev.mi.47.100193.001123. [DOI] [PubMed] [Google Scholar]
- Dean D. A., Kasamatsu H. Signal- and energy-dependent nuclear transport of SV40 Vp3 by isolated nuclei. Establishment of a filtration assay for nuclear protein import. J Biol Chem. 1994 Feb 18;269(7):4910–4916. [PubMed] [Google Scholar]
- Dingwall C., Robbins J., Dilworth S. M., Roberts B., Richardson W. D. The nucleoplasmin nuclear location sequence is larger and more complex than that of SV-40 large T antigen. J Cell Biol. 1988 Sep;107(3):841–849. doi: 10.1083/jcb.107.3.841. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Dombrowski J. E., Schroeder M. R., Bednarek S. Y., Raikhel N. V. Determination of the functional elements within the vacuolar targeting signal of barley lectin. Plant Cell. 1993 May;5(5):587–596. doi: 10.1105/tpc.5.5.587. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Dwyer N., Blobel G. A modified procedure for the isolation of a pore complex-lamina fraction from rat liver nuclei. J Cell Biol. 1976 Sep;70(3):581–591. doi: 10.1083/jcb.70.3.581. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Forbes D. J. Structure and function of the nuclear pore complex. Annu Rev Cell Biol. 1992;8:495–527. doi: 10.1146/annurev.cb.08.110192.002431. [DOI] [PubMed] [Google Scholar]
- Garcia-Bustos J. F., Wagner P., Hall M. N. Yeast cell-free nuclear protein import requires ATP hydrolysis. Exp Cell Res. 1991 Jan;192(1):213–219. doi: 10.1016/0014-4827(91)90178-w. [DOI] [PubMed] [Google Scholar]
- Garcia-Bustos J., Heitman J., Hall M. N. Nuclear protein localization. Biochim Biophys Acta. 1991 Mar 7;1071(1):83–101. doi: 10.1016/0304-4157(91)90013-m. [DOI] [PubMed] [Google Scholar]
- Goday A., Jensen A. B., Culiáez-Macià F. A., Mar Albà M., Figueras M., Serratosa J., Torrent M., Pagès M. The maize abscisic acid-responsive protein Rab17 is located in the nucleus and interacts with nuclear localization signals. Plant Cell. 1994 Mar;6(3):351–360. doi: 10.1105/tpc.6.3.351. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Goldfarb D. S., Gariépy J., Schoolnik G., Kornberg R. D. Synthetic peptides as nuclear localization signals. Nature. 1986 Aug 14;322(6080):641–644. doi: 10.1038/322641a0. [DOI] [PubMed] [Google Scholar]
- Gu Z., Moerschell R. P., Sherman F., Goldfarb D. S. NIP1, a gene required for nuclear transport in yeast. Proc Natl Acad Sci U S A. 1992 Nov 1;89(21):10355–10359. doi: 10.1073/pnas.89.21.10355. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Haino M., Kawahire S., Omata S., Horigome T. Purification of a 60 kDa nuclear localization signal binding protein in rat liver nuclear envelopes and characterization of its properties. J Biochem. 1993 Mar;113(3):308–313. doi: 10.1093/oxfordjournals.jbchem.a124044. [DOI] [PubMed] [Google Scholar]
- Hall M. N., Hereford L., Herskowitz I. Targeting of E. coli beta-galactosidase to the nucleus in yeast. Cell. 1984 Apr;36(4):1057–1065. doi: 10.1016/0092-8674(84)90055-2. [DOI] [PubMed] [Google Scholar]
- Harter K., Kircher S., Frohnmeyer H., Krenz M., Nagy F., Schäfer E. Light-regulated modification and nuclear translocation of cytosolic G-box binding factors in parsley. Plant Cell. 1994 Apr;6(4):545–559. doi: 10.1105/tpc.6.4.545. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Hicks G. R., Raikhel N. V. Specific binding of nuclear localization sequences to plant nuclei. Plant Cell. 1993 Aug;5(8):983–994. doi: 10.1105/tpc.5.8.983. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Imamoto N., Matsuoka Y., Kurihara T., Kohno K., Miyagi M., Sakiyama F., Okada Y., Tsunasawa S., Yoneda Y. Antibodies against 70-kD heat shock cognate protein inhibit mediated nuclear import of karyophilic proteins. J Cell Biol. 1992 Dec;119(5):1047–1061. doi: 10.1083/jcb.119.5.1047. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Kalderon D., Richardson W. D., Markham A. F., Smith A. E. Sequence requirements for nuclear location of simian virus 40 large-T antigen. Nature. 1984 Sep 6;311(5981):33–38. doi: 10.1038/311033a0. [DOI] [PubMed] [Google Scholar]
- Kalinich J. F., Douglas M. G. In vitro translocation through the yeast nuclear envelope. Signal-dependent transport requires ATP and calcium. J Biol Chem. 1989 Oct 25;264(30):17979–17989. [PubMed] [Google Scholar]
- Kornbluth S., Dasso M., Newport J. Evidence for a dual role for TC4 protein in regulating nuclear structure and cell cycle progression. J Cell Biol. 1994 May;125(4):705–719. doi: 10.1083/jcb.125.4.705. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Lanford R. E., Butel J. S. Construction and characterization of an SV40 mutant defective in nuclear transport of T antigen. Cell. 1984 Jul;37(3):801–813. doi: 10.1016/0092-8674(84)90415-x. [DOI] [PubMed] [Google Scholar]
- Lassner M. W., Jones A., Daubert S., Comai L. Targeting of T7 RNA polymerase to tobacco nuclei mediated by an SV40 nuclear location signal. Plant Mol Biol. 1991 Aug;17(2):229–234. doi: 10.1007/BF00039497. [DOI] [PubMed] [Google Scholar]
- Lee W. C., Mélèse T. Identification and characterization of a nuclear localization sequence-binding protein in yeast. Proc Natl Acad Sci U S A. 1989 Nov;86(22):8808–8812. doi: 10.1073/pnas.86.22.8808. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Lee W. C., Zabetakis D., Mélèse T. NSR1 is required for pre-rRNA processing and for the proper maintenance of steady-state levels of ribosomal subunits. Mol Cell Biol. 1992 Sep;12(9):3865–3871. doi: 10.1128/mcb.12.9.3865. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Meier U. T., Blobel G. Nopp140 shuttles on tracks between nucleolus and cytoplasm. Cell. 1992 Jul 10;70(1):127–138. doi: 10.1016/0092-8674(92)90539-o. [DOI] [PubMed] [Google Scholar]
- Moore M. S., Blobel G. A G protein involved in nucleocytoplasmic transport: the role of Ran. Trends Biochem Sci. 1994 May;19(5):211–216. doi: 10.1016/0968-0004(94)90024-8. [DOI] [PubMed] [Google Scholar]
- Raikhel N. Nuclear targeting in plants. Plant Physiol. 1992 Dec;100(4):1627–1632. doi: 10.1104/pp.100.4.1627. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Schlenstedt G., Hurt E., Doye V., Silver P. A. Reconstitution of nuclear protein transport with semi-intact yeast cells. J Cell Biol. 1993 Nov;123(4):785–798. doi: 10.1083/jcb.123.4.785. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Shi Y., Thomas J. O. The transport of proteins into the nucleus requires the 70-kilodalton heat shock protein or its cytosolic cognate. Mol Cell Biol. 1992 May;12(5):2186–2192. doi: 10.1128/mcb.12.5.2186. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Shieh M. W., Wessler S. R., Raikhel N. V. Nuclear targeting of the maize R protein requires two nuclear localization sequences. Plant Physiol. 1993 Feb;101(2):353–361. doi: 10.1104/pp.101.2.353. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Varagona M. J., Raikhel N. V. The basic domain in the bZIP regulatory protein Opaque2 serves two independent functions: DNA binding and nuclear localization. Plant J. 1994 Feb;5(2):207–214. doi: 10.1046/j.1365-313x.1994.05020207.x. [DOI] [PubMed] [Google Scholar]
- Varagona M. J., Schmidt R. J., Raikhel N. V. Monocot regulatory protein Opaque-2 is localized in the nucleus of maize endosperm and transformed tobacco plants. Plant Cell. 1991 Feb;3(2):105–113. doi: 10.1105/tpc.3.2.105. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Varagona M. J., Schmidt R. J., Raikhel N. V. Nuclear localization signal(s) required for nuclear targeting of the maize regulatory protein Opaque-2. Plant Cell. 1992 Oct;4(10):1213–1227. doi: 10.1105/tpc.4.10.1213. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Yan C., Mélèse T. Multiple regions of NSR1 are sufficient for accumulation of a fusion protein within the nucleolus. J Cell Biol. 1993 Dec;123(5):1081–1091. doi: 10.1083/jcb.123.5.1081. [DOI] [PMC free article] [PubMed] [Google Scholar]
- van der Krol A. R., Chua N. H. The basic domain of plant B-ZIP proteins facilitates import of a reporter protein into plant nuclei. Plant Cell. 1991 Jul;3(7):667–675. doi: 10.1105/tpc.3.7.667. [DOI] [PMC free article] [PubMed] [Google Scholar]