Timely activation and inactivation of Cyclin dependent kinases (CDKs) regulate most cell cycle transitions. Precise coordination of each cell cycle step with the others is essential for cells to correctly transmit an intact genome to each daughter cell. Failure to do so can lead to polyploidy, genomic instability and cancer. The function of phosphatases which reverse the action of CDKs is less well understood. The highly conserved Cdc14-family phosphatases act to reverse Cdk phosphorylation events. Most of our knowledge about Cdc14 phosphatases has come from yeast. Key unanswered questions about this family of phosphatases are how they are regulated, what are their targets, and how does the phosphatase regulate these targets to promote key steps of mitosis and cytokinesis? We have been studying the fission yeast Cdc14 homolog, known as Clp1. Our work previous work showed that Clp1 activity is closely integrated with the activities of other key cell cycle regulators. In addition, we found that Clp1 is required to promote proper chromosome segregation, cytokinesis, and inactivation of Cdk1 at the end of mitosis. These studies have identified potential targets for Clp1 involved in each of these important steps. In this proposal we will exploit these results to define in molecular terms how Clp1 is regulated, and how it acts to promote chromosome segregation, cytokinesis, and Cdk1 inactivation. The involvement of Clp1 in these various steps in cell cycle progression makes Clp1 a central regulator for controlling key cell cycle events and promoting genomic stability.
Our specific aims are: 1) To test the model that proper chromosome segregation requires a carefully regulated equilibrium between Cdk1 phosphorylation and Clp1 dephosphorylation of Survivin and INCENP. 2) To test a hypothesis for how the Sid2 kinase and the 14-3-3 protein, Rad24, maintain elevated Clp1 activity until cytokinesis is complete. 3) To test a hypothesis that Clp1 promotes actomyosin ring stability through effects on Cdc15. 4) To determine how Clp1 and the anaphase promoting complex promote Cdc25 inactivation in late mitosis. ? ? ?

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Research Project (R01)
Project #
5R01GM068786-06
Application #
7470556
Study Section
Nuclear Dynamics and Transport (NDT)
Program Officer
Zatz, Marion M
Project Start
2003-09-19
Project End
2011-08-31
Budget Start
2008-09-01
Budget End
2009-08-31
Support Year
6
Fiscal Year
2008
Total Cost
$307,591
Indirect Cost
Name
University of Massachusetts Medical School Worcester
Department
Genetics
Type
Schools of Medicine
DUNS #
603847393
City
Worcester
State
MA
Country
United States
Zip Code
01655
Ma, Hanhui; McLean, Janel R; Gould, Kathleen L et al. (2014) An efficient fluorescent protein-based multifunctional affinity purification approach in mammalian cells. Methods Mol Biol 1177:175-91
Lu, Lucy X; Domingo-Sananes, Maria Rosa; Huzarska, Malwina et al. (2012) Multisite phosphoregulation of Cdc25 activity refines the mitotic entrance and exit switches. Proc Natl Acad Sci U S A 109:9899-904
Broadus, Matthew R; Gould, Kathleen L (2012) Multiple protein kinases influence the redistribution of fission yeast Clp1/Cdc14 phosphatase upon genotoxic stress. Mol Biol Cell 23:4118-28
Choi, Sung Hugh; McCollum, Dannel (2012) A role for metaphase spindle elongation forces in correction of merotelic kinetochore attachments. Curr Biol 22:225-30
Ma, Hanhui; McLean, Janel R; Chao, Lucy Fang-I et al. (2012) A highly efficient multifunctional tandem affinity purification approach applicable to diverse organisms. Mol Cell Proteomics 11:501-11
Goettel, Jeremy A; Liang, Dongchun; Hilliard, Valda C et al. (2011) KSR1 is a functional protein kinase capable of serine autophosphorylation and direct phosphorylation of MEK1. Exp Cell Res 317:452-63
Chen, Jun-Song; Lu, Lucy X; Ohi, Melanie D et al. (2011) Cdk1 phosphorylation of the kinetochore protein Nsk1 prevents error-prone chromosome segregation. J Cell Biol 195:583-93
Roberts-Galbraith, Rachel H; Ohi, Melanie D; Ballif, Bryan A et al. (2010) Dephosphorylation of F-BAR protein Cdc15 modulates its conformation and stimulates its scaffolding activity at the cell division site. Mol Cell 39:86-99
Kouranti, Ilektra; McLean, Janel R; Feoktistova, Anna et al. (2010) A global census of fission yeast deubiquitinating enzyme localization and interaction networks reveals distinct compartmentalization profiles and overlapping functions in endocytosis and polarity. PLoS Biol 8:
Choi, Sung Hugh; Péli-Gulli, Marie-Pierre; Mcleod, Iain et al. (2009) Phosphorylation state defines discrete roles for monopolin in chromosome attachment and spindle elongation. Curr Biol 19:985-95

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