Rapid changes in cell physiology during cell cycle transitions or in response to changes in external conditions are often mediated by the degradation of regulatory molecules. These changes are typically directed by the modification of protein targets with chains of the small protein ubiquitin. Ubiquitinization is carried out by a series of three enzymes, sometimes referred to as E1, E2 and E3, which function in tandem to transfer ubiquitin to a substrate. Substrate specificity is usually mediated by the E3 complex, also called an ubiquitin ligase. The SCF and the APC represent two highly conserved multi-subunit ubiquitin ligases important for both cell cycle progression and the regulation of many aspects of cellular physiology. We will examine mechanisms of APC regulation, and also identify the substrates other ubiquitin ligases using a biochemical technique that we have recently developed. Finally, we will explore the turnover of one ubiquitin ligase substrate, a G1 cyclin, in greater detail.

Public Health Relevance

Cancer is the result of uncontrolled cell division. In this proposal, we outline experiments that characterize proteins responsible for the regulation of cell division. In doing this, we can better understand how cancers arise and the characteristics of tumors that can be used to selectively target them.

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Research Project (R01)
Project #
3R01GM070539-11S1
Application #
8911416
Study Section
Cellular Signaling and Regulatory Systems Study Section (CSRS)
Program Officer
Hamlet, Michelle R
Project Start
2004-06-01
Project End
2016-04-30
Budget Start
2014-05-01
Budget End
2015-04-30
Support Year
11
Fiscal Year
2014
Total Cost
$34,100
Indirect Cost
$12,518
Name
University of California San Francisco
Department
Type
Schools of Medicine
DUNS #
094878337
City
San Francisco
State
CA
Country
United States
Zip Code
94143
Mark, Kevin G; Meza-Gutierrez, Fernando; Johnson, Jeffrey R et al. (2015) Prb1 Protease Activity Is Required for Its Recognition by the F-Box Protein Saf1. Biochemistry 54:4423-6
Mark, Kevin G; Simonetta, Marco; Maiolica, Alessio et al. (2014) Ubiquitin ligase trapping identifies an SCF(Saf1) pathway targeting unprocessed vacuolar/lysosomal proteins. Mol Cell 53:148-61
Edenberg, Ellen R; Vashisht, Ajay A; Topacio, Benjamin R et al. (2014) Hst3 is turned over by a replication stress-responsive SCF(Cdc4) phospho-degron. Proc Natl Acad Sci U S A 111:5962-7
Landry, Benjamin D; Doyle, John P; Toczyski, David P et al. (2012) F-box protein specificity for g1 cyclins is dictated by subcellular localization. PLoS Genet 8:e1002851
Foe, Ian T; Foster, Scott A; Cheung, Stephanie K et al. (2011) Ubiquitination of Cdc20 by the APC occurs through an intramolecular mechanism. Curr Biol 21:1870-7
Benanti, Jennifer A; Matyskiela, Mary E; Morgan, David O et al. (2009) Functionally distinct isoforms of Cik1 are differentially regulated by APC/C-mediated proteolysis. Mol Cell 33:581-90
Benanti, Jennifer A; Toczyski, David P (2008) Cdc20, an activator at last. Mol Cell 32:460-1
Vega, Leticia R; Phillips, Jane A; Thornton, Brian R et al. (2007) Sensitivity of yeast strains with long G-tails to levels of telomere-bound telomerase. PLoS Genet 3:e105