We are using the budding yeast Saccharomyces cerevisiae to understand how eukaryotic cells limit DNA replication to one round per cell cycle. Disruption of this regulation can lead to genomic instability, one of the hallmarks of cancer. One conserved mechanism to prevent re-replication is to exclude initiation I proteins from the nucleus after replication initiation has occurred. In budding yeast, nuclear exclusion of the heterohexameric Mcm2-7 replication complex occurs through regulation of Mcm nucleocytoplasmic transport by the cyclin-dependent kinase Cdc28. We have identified nuclear localization signals (NLSs) on Mcm2 and Mcm3 and a potential nuclear export signal (NES) on Mcm3. We have also shown that Cdc28 phosphorylation of Mcm3 near its NLS and NES promotes the net nuclear export of the Mcm2-7 complex. This phosphorylation could work by inhibiting nuclear import, stimulating nuclear export, or doing both. To investigate these possibilities, I will pursue the following specific aims:
Aim 1 : Determine whether and how Cdc28 regulates Mcm nuclear import Aim 2: Determine whether and how Cdc28 regulates Mcm nuclear export

Agency
National Institute of Health (NIH)
Institute
National Cancer Institute (NCI)
Type
Predoctoral Individual National Research Service Award (F31)
Project #
5F31CA110268-04
Application #
7282440
Study Section
Special Emphasis Panel (ZRG1-CDF-1 (29))
Program Officer
Bini, Alessandra M
Project Start
2004-09-01
Project End
2008-08-31
Budget Start
2007-09-01
Budget End
2008-08-31
Support Year
4
Fiscal Year
2007
Total Cost
$30,615
Indirect Cost
Name
University of California San Francisco
Department
Microbiology/Immun/Virology
Type
Schools of Medicine
DUNS #
094878337
City
San Francisco
State
CA
Country
United States
Zip Code
94143
Moses, Alan M; Liku, Muluye E; Li, Joachim J et al. (2007) Regulatory evolution in proteins by turnover and lineage-specific changes of cyclin-dependent kinase consensus sites. Proc Natl Acad Sci U S A 104:17713-8
Liku, Muluye E; Nguyen, Van Q; Rosales, Audrey W et al. (2005) CDK phosphorylation of a novel NLS-NES module distributed between two subunits of the Mcm2-7 complex prevents chromosomal rereplication. Mol Biol Cell 16:5026-39