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

 Previous Article  |  Next Article 

Molecular and Cellular Biology, April 2004, p. 3262-3276, Vol. 24, No. 8
0270-7306/04/$08.00+0     DOI: 10.1128/MCB.24.8.3262-3276.2004
Copyright © 2004, American Society for Microbiology. All Rights Reserved.

Initiation of Cytokinesis Is Controlled through Multiple Modes of Regulation of the Sid2p-Mob1p Kinase Complex

Ming-Chin Hou, David A. Guertin,{dagger} and Dannel McCollum*

Department of Molecular Genetics and Microbiology and Program in Cell Dynamics, University of Massachusetts Medical School, Worcester, Massachusetts 01605

Received 27 August 2003/ Returned for modification 6 October 2003/ Accepted 25 January 2004

The Sid2p-Mob1p kinase complex is an important component of the septation initiation network (SIN) in the fission yeast Schizosaccharomyces pombe. However, regulation of this complex is still elusive. Here we show that Mob1p is required not only for the subcellular localization of Sid2p but also for its kinase activity. We identified a region at the amino terminus of Sid2p that is required for Mob1p binding and spindle pole body (SPB) localization. Deletion of this region abolishes Mob1p binding and diminishes SPB localization, whereas this region alone is sufficient to associate with Mob1p and SPBs. We further show that a similar region of the N terminus of the Sid2p-related protein kinase Orb6p binds to the Mob1p-related protein Mob2p, suggesting that this may be a conserved mode of interaction for this family of kinases. Phosphorylation of Ser402 and especially Thr578 is important for Sid2p function. Sid2p with a mutation of Thr578 to Ala (T578A) can no longer rescue sid2-250 mutant cells, and this results in reduction of Mob1p binding. Sid2p mutants mimicking phosphorylation at this site (T578D and T578E) can rescue sid2-250 cells, enhance Sid2p kinase activity, and partially rescue growth defects of upstream sin mutants. Interestingly, Sid2p, but not Mob1p, is self-associated. Our experiments suggest that self-associated Sid2p is inactive. This self-association is mediated by a region that overlaps with Mob1p and SPB binding sites. Overexpression of Mob1p is able to disrupt the self-association of Sid2p. Taken together, our results suggest that Sid2p kinase may utilize multiple modes of regulation including self-association, Mob1p binding, and phosphorylation to achieve its full activity at an appropriate time and place in the cell.

* Corresponding author. Mailing address: Department of Molecular Genetics and Microbiology and Program in Cell Dynamics, University of Massachusetts Medical School, Worcester, MA 01605. Phone: (508) 856-8767. Fax: (508) 856-8774. E-mail: dannel.mccollum{at}umassmed.edu.

{dagger} Present address: Whitehead Institute for Biomedical Research, Cambridge, MA 02142.

Molecular and Cellular Biology, April 2004, p. 3262-3276, Vol. 24, No. 8
0022-538X/04/$08.00+0     DOI: 10.1128/MCB.24.8.3262-3276.2004
Copyright © 2004, American Society for Microbiology. All Rights Reserved.



This article has been cited by other articles:

  • Yan, H., Ge, W., Chew, T. G., Chow, J. Y., McCollum, D., Neiman, A. M., Balasubramanian, M. K. (2008). The Meiosis-Specific Sid2p-related Protein Slk1p Regulates Forespore Membrane Assembly in Fission Yeast. Mol. Biol. Cell 19: 3676-3690 [Abstract] [Full Text]  
  • Trammell, M. A., Mahoney, N. M., Agard, D. A., Vale, R. D. (2008). Mob4 plays a role in spindle focusing in Drosophila S2 cells. J. Cell Sci. 121: 1284-1292 [Abstract] [Full Text]  
  • Yabuta, N., Okada, N., Ito, A., Hosomi, T., Nishihara, S., Sasayama, Y., Fujimori, A., Okuzaki, D., Zhao, H., Ikawa, M., Okabe, M., Nojima, H. (2007). Lats2 Is an Essential Mitotic Regulator Required for the Coordination of Cell Division. J. Biol. Chem. 282: 19259-19271 [Abstract] [Full Text]  
  • Kim, J.-M., Lu, L., Shao, R., Chin, J., Liu, B. (2006). Isolation of Mutations That Bypass the Requirement of the Septation Initiation Network for Septum Formation and Conidiation in Aspergillus nidulans. Genetics 173: 685-696 [Abstract] [Full Text]  
  • Stegert, M. R., Hergovich, A., Tamaskovic, R., Bichsel, S. J., Hemmings, B. A. (2005). Regulation of NDR Protein Kinase by Hydrophobic Motif Phosphorylation Mediated by the Mammalian Ste20-Like Kinase MST3. Mol. Cell. Biol. 25: 11019-11029 [Abstract] [Full Text]  
  • Bothos, J., Tuttle, R. L., Ottey, M., Luca, F. C., Halazonetis, T. D. (2005). Human LATS1 Is a Mitotic Exit Network Kinase. Cancer Res. 65: 6568-6575 [Abstract] [Full Text]  


Copyright © 2009 by the American Society for Microbiology.   For an alternate route to Journals.ASM.org, visit: http://intl-journals.asm.org | More Info»