The retinoblastoma family of proteins is a key regulator of cell cycle progression, differentiation, and apoptosis. These tumor suppressors that play a key role in oncogenesis are """"""""active"""""""" when in a hypo-phosphorylated state. O-linked N-acetylglucosamine (O- GlcNAc) is an abundant and dynamic post-translational modification of cytoplasmic proteins. This modification that occurs on serine/threonine residues appears to be reciprocal in many ways to phosphorylation. Since preliminary data has identified O-GlcNAc on some members of the retinoblastoma family of proteins, this grant seeks to determine the functional consequences of O-GlcNAc modification of the retinoblastoma family of tumor suppressors. The following hypotheses will be tested: (1) that O-GlcNAcylation and serine/threonine phosphorylation of the retinoblastoma family of proteins occur in a reciprocal cell cycle-dependent manner; (2) that O-GlcNAc plays a critical role in protein-protein interaction; and (3) that O- GlcNAc protects the retinoblastoma family of proteins from degradation via the apoptotic caspase pathway. These hypotheses will be tested by the completion of the following specific aims: (1) to characterize the O-GlcNAc modification of Rb, RBL1 (p107), and RBL2 (p130, RB2); and (2) to elucidate the role of O-GlcNAc in retinoblastoma family of protein-protein interactions.

Agency
National Institute of Health (NIH)
Institute
National Cancer Institute (NCI)
Type
Postdoctoral Individual National Research Service Award (F32)
Project #
5F32CA083261-03
Application #
6377519
Study Section
Special Emphasis Panel (ZRG1-SSS-1 (01))
Program Officer
Lohrey, Nancy
Project Start
2001-09-30
Project End
Budget Start
2001-09-30
Budget End
2002-09-29
Support Year
3
Fiscal Year
2001
Total Cost
$41,996
Indirect Cost
Name
Johns Hopkins University
Department
Biochemistry
Type
Schools of Medicine
DUNS #
045911138
City
Baltimore
State
MD
Country
United States
Zip Code
21218
Wells, Lance; Slawson, Chad; Hart, Gerald W (2011) The E2F-1 associated retinoblastoma-susceptibility gene product is modified by O-GlcNAc. Amino Acids 40:877-83
Wells, L; Vosseller, K; Hart, G W (2003) A role for N-acetylglucosamine as a nutrient sensor and mediator of insulin resistance. Cell Mol Life Sci 60:222-8
Vosseller, Keith; Sakabe, Kaoru; Wells, Lance et al. (2002) Diverse regulation of protein function by O-GlcNAc: a nuclear and cytoplasmic carbohydrate post-translational modification. Curr Opin Chem Biol 6:851-7
Wells, Lance; Vosseller, Keith; Cole, Robert N et al. (2002) Mapping sites of O-GlcNAc modification using affinity tags for serine and threonine post-translational modifications. Mol Cell Proteomics 1:791-804
Vosseller, Keith; Wells, Lance; Lane, M Daniel et al. (2002) Elevated nucleocytoplasmic glycosylation by O-GlcNAc results in insulin resistance associated with defects in Akt activation in 3T3-L1 adipocytes. Proc Natl Acad Sci U S A 99:5313-8
Wells, Lance; Gao, Yuan; Mahoney, James A et al. (2002) Dynamic O-glycosylation of nuclear and cytosolic proteins: further characterization of the nucleocytoplasmic beta-N-acetylglucosaminidase, O-GlcNAcase. J Biol Chem 277:1755-61
Wells, L; Vosseller, K; Hart, G W (2001) Glycosylation of nucleocytoplasmic proteins: signal transduction and O-GlcNAc. Science 291:2376-8
Comer, F I; Vosseller, K; Wells, L et al. (2001) Characterization of a mouse monoclonal antibody specific for O-linked N-acetylglucosamine. Anal Biochem 293:169-77