Molecular Biology of the Cell Call for Nominations: MBC Editor-in-Chief

Home Help [Feedback] [For Subscribers] [Archive] [Search] --
QUICK SEARCH:   [advanced]


     

MBC in Press, published online ahead of print November 10, 2004
Mol. Biol. Cell 10.1091/mbc.E04-06-0502

A more recent version of this article appeared on January 1, 2005
This Article
Right arrow Full Text (PDF)
Right arrow Supplemental Material
Right arrow All Versions of this Article:
E04-06-0502v1
16/1/358    most recent
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 arrow reprints & permissions
Citing Articles
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Karagiannis, J.
Right arrow Articles by Balasubramanian, M. K.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Karagiannis, J.
Right arrow Articles by Balasubramanian, M. K.

Submitted on June 21, 2004
Accepted on November 1, 2004

The Nuclear Kinase, Lsk1p, Positively Regulates the Septation Initiation Network and Promotes the Successful Completion of Cytokinesis in Response to Perturbation of the Actomyosin Ring in Schizosaccharomyces pombe

Jim Karagiannis,*{dagger} Andrea Bimbó,* Srividya Rajagopalan,* Jianhua Liu,{ddagger} and Mohan K. Balasubramanian*

*Laboratory of Cell Division, Temasek Life Sciences Laboratory, Singapore 117604, Singapore; {ddagger}Genome Institute of Singapore, Singapore 138672, Singapore

Monitoring Editor: Randy Schekman

Cytokinesis in fission yeast requires the function of an actomyosin based contractile ring whose constriction is dependent on a signaling module termed the septation initiation network (SIN). In response to minor perturbation of the ring the duration of SIN signaling is extended concurrently with a delay in nuclear cycle progression. These mechanisms require the conserved phosphatase, Clp1p/Flp1p, and facilitate the successful completion of cytokinesis thereby increasing cellular viability. To isolate novel components of this cytokinesis monitoring system we screened a genome wide bank of protein kinase deletion mutants and identified Lsk1p, a nuclear-localized protein kinase. Similar to clp1{Delta} mutants, and in contrast to wild-type, lsk1{Delta} cells are unable to maintain the integrity of the actomyosin ring upon treatment with low doses (0.3 µM) of Latrunculin A. However, unlike clp1{Delta} mutants, lsk1{Delta} cells are competent to delay nuclear cycle progression following cytokinetic failure. In addition, lsk1{Delta} mutants suppress the lethal, multi-septate phenotype conferred by hyper-activation of the SIN demonstrating that Lsk1p is a positive regulator of this module. In this report we demonstrate that Lsk1p acts in parallel to Clp1p to promote actomyosin ring stability upon checkpoint activation. Our studies also establish that actomyosin ring maintenance and nuclear cycle delay in response to cytokinetic perturbation can be genetically resolved into independent pathways.

{dagger}Corresponding author. E-mail: jim{at}tll.org.sg






Home Help [Feedback] [For Subscribers] [Archive] [Search] --
Copyright © 2004 by The American Society for Cell Biology. Terms of copyright protection, warranties, and disclaimers.