This Article Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Reprints and Permissions Copyright Information Books from ASM Press MicrobeWorld Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Leslie, D. M. Articles by Aitchison, J. D. Search for Related Content PubMed PubMed Citation Articles by Leslie, D. M. Articles by Aitchison, J. D.

 Previous Article  |  Next Article 

Molecular and Cellular Biology, April 2002, p. 2544-2555, Vol. 22, No. 8
0270-7306/02/$04.00+0     DOI: 10.1128/MCB.22.8.2544-2555.2002
Copyright © 2002, American Society for Microbiology. All Rights Reserved.

Kap121p-Mediated Nuclear Import Is Required for Mating and Cellular Differentiation in Yeast

Institute for Systems Biology, Seattle, Washington 98105,¹ Department of Cell Biology, University of Alberta, Edmonton, Alberta T6G 2H7, Canada,² Laboratory of Structural Cellular Biology, The Rockefeller University, New York, New York 10021³

Received 3 October 2001/ Returned for modification 5 November 2001/ Accepted 15 January 2002

To further our understanding of how the nucleocytoplasmic transport machinery interfaces with its cargoes and how this affects cellular physiology, we investigated the molecular mechanisms of phenotypes associated with mutations in karyopherin Kap121p. Two previously unreported phenotypes of kap121 cells were observed: defects in mating and in the transition from the normal yeast form to the pseudohyphal, invasive form. In parallel, we searched for Kap121p cargoes by using Kap121p as a probe in overlay assays of yeast nuclear proteins. One of the major interacting proteins identified by this procedure was Ste12p, a transcription factor central to both the mating response and the pseudohyphal transition. We therefore investigated whether defects in these differentiation processes were due to an inability to import Ste12p. Both immunopurification and in vitro binding studies demonstrated that Ste12p interacted specifically with Kap121p in a Ran-GTP-sensitive manner and that Ste12p was mislocalized to the cytoplasm by inactivation of Kap121p in a temperature-sensitive mutant. The Kap121p-specific nuclear localization signal (NLS) of Ste12p was determined to reside within a C-terminal region of Ste12p. Furthermore, by overexpression of STE12 or expression of a STE12-cNLS fusion in kap121 cells, the invasive-growth defect and the mating defect were both suppressed. Together these data demonstrate that Ste12p is imported into nuclei by Kap121p and that mating and differentiation defects associated with kap121 mutants are primarily attributable to the mislocalization of Ste12p.

This article has been cited by other articles:

• Palancade, B., Liu, X., Garcia-Rubio, M., Aguilera, A., Zhao, X., Doye, V. (2007). Nucleoporins Prevent DNA Damage Accumulation by Modulating Ulp1-dependent Sumoylation Processes. Mol. Biol. Cell 18: 2912-2923 [Abstract] [Full Text]  
• Makhnevych, T., Ptak, C., Lusk, C. P., Aitchison, J. D., Wozniak, R. W. (2007). The role of karyopherins in the regulated sumoylation of septins. J. Cell Biol. 177: 39-49 [Abstract] [Full Text]  
• Timney, B. L., Tetenbaum-Novatt, J., Agate, D. S., Williams, R., Zhang, W., Chait, B. T., Rout, M. P. (2006). Simple kinetic relationships and nonspecific competition govern nuclear import rates in vivo. J. Cell Biol. 175: 579-593 [Abstract] [Full Text]  
• Bakhrat, A., Baranes, K., Krichevsky, O., Rom, I., Schlenstedt, G., Pietrokovski, S., Raveh, D. (2006). Nuclear Import of Ho Endonuclease Utilizes Two Nuclear Localization Signals and Four Importins of the Ribosomal Import System. J. Biol. Chem. 281: 12218-12226 [Abstract] [Full Text]  
• Scott, R. J., Lusk, C. P., Dilworth, D. J., Aitchison, J. D., Wozniak, R. W. (2005). Interactions between Mad1p and the Nuclear Transport Machinery in the Yeast Saccharomyces cerevisiae. Mol. Biol. Cell 16: 4362-4374 [Abstract] [Full Text]  
• Leslie, D. M., Zhang, W., Timney, B. L., Chait, B. T., Rout, M. P., Wozniak, R. W., Aitchison, J. D. (2004). Characterization of Karyopherin Cargoes Reveals Unique Mechanisms of Kap121p-Mediated Nuclear Import. Mol. Cell. Biol. 24: 8487-8503 [Abstract] [Full Text]  
• Ueta, R., Fukunaka, A., Yamaguchi-Iwai, Y. (2003). Pse1p Mediates the Nuclear Import of the Iron-responsive Transcription Factor Aft1p in Saccharomyces cerevisiae. J. Biol. Chem. 278: 50120-50127 [Abstract] [Full Text]  
• Sydorskyy, Y., Dilworth, D. J., Yi, E. C., Goodlett, D. R., Wozniak, R. W., Aitchison, J. D. (2003). Intersection of the Kap123p-Mediated Nuclear Import and Ribosome Export Pathways. Mol. Cell. Biol. 23: 2042-2054 [Abstract] [Full Text]  
• Lusk, C. P., Makhnevych, T., Marelli, M., Aitchison, J. D., Wozniak, R. W. (2002). Karyopherins in nuclear pore biogenesis: a role for Kap121p in the assembly of Nup53p into nuclear pore complexes. J. Cell Biol. 159: 267-278 [Abstract] [Full Text]  
• Smith, J. J., Marelli, M., Christmas, R. H., Vizeacoumar, F. J., Dilworth, D. J., Ideker, T., Galitski, T., Dimitrov, K., Rachubinski, R. A., Aitchison, J. D. (2002). Transcriptome profiling to identify genes involved in peroxisome assembly and function. J. Cell Biol. 158: 259-271 [Abstract] [Full Text]