The retinoblastoma (Rb) protein is a key cell-cycle regulator disrupted in many cancers, and thus a molecular picture of Rb function is important for understanding mechanisms of tumorigenesis. Rb binds members of the E2F transcription factor family and thereby inhibits the expression of genes required for cell-cycle progression. Multiple phosphorylations of Rb dissociate Rb-E2F complexes, and this process is regulated by Cyclin-dependent kinases (Cdks) and protein phosphatase 1 (PP1). The objective of this proposal is to understand in molecular detail how phosphorylation disrupts Rb-E2F binding and how Cdks and PP1 phosphorylate and dephosphorylate Rb. A number of biophysical and structural techniques including x-ray crystallography, nuclear magnetic resonance, mass spectrometry, and calorimetry, will be applied to characterize the protein interactions of Rb with E2F, Cdks and PP1. Tumor cells invariably have defects in the biochemical mechanisms that regulate cell growth and division, so understanding how these processes work is vital to understanding cancer. This proposal aims to develop a molecular picture of how a cell-cycle regulator known as the retinoblastoma protein functions.

Agency
National Institute of Health (NIH)
Institute
National Cancer Institute (NCI)
Type
Research Project (R01)
Project #
5R01CA132685-05
Application #
8267078
Study Section
Macromolecular Structure and Function C Study Section (MSFC)
Program Officer
Knowlton, John R
Project Start
2008-08-19
Project End
2013-05-31
Budget Start
2012-06-01
Budget End
2013-05-31
Support Year
5
Fiscal Year
2012
Total Cost
$291,951
Indirect Cost
$90,676
Name
University of California Santa Cruz
Department
Chemistry
Type
Schools of Arts and Sciences
DUNS #
125084723
City
Santa Cruz
State
CA
Country
United States
Zip Code
95064
Burke, Jason R; Liban, Tyler J; Restrepo, Tamara et al. (2014) Multiple mechanisms for E2F binding inhibition by phosphorylation of the retinoblastoma protein C-terminal domain. J Mol Biol 426:245-55
Rubin, Seth M (2013) Deciphering the retinoblastoma protein phosphorylation code. Trends Biochem Sci 38:12-9
Schachter, Miriam Merzel; Merrick, Karl A; Larochelle, Stephane et al. (2013) A Cdk7-Cdk4 T-loop phosphorylation cascade promotes G1 progression. Mol Cell 50:250-60
Dick, Frederick A; Rubin, Seth M (2013) Molecular mechanisms underlying RB protein function. Nat Rev Mol Cell Biol 14:297-306
Balog, Eva Rose M; Burke, Jason R; Hura, Greg L et al. (2011) Crystal structure of the unliganded retinoblastoma protein pocket domain. Proteins 79:2010-4
Burke, Jason R; Deshong, Alison J; Pelton, Jeffrey G et al. (2010) Phosphorylation-induced conformational changes in the retinoblastoma protein inhibit E2F transactivation domain binding. J Biol Chem 285:16286-93
Hirschi, Alexander; Cecchini, Matthew; Steinhardt, Rachel C et al. (2010) An overlapping kinase and phosphatase docking site regulates activity of the retinoblastoma protein. Nat Struct Mol Biol 17:1051-7