The long-term stated goal of this proposal is to understand how auxiliary factors modulate transcriptional regulation by the thyroid hormone receptor (TR). This investigator has isolated a distinct group of novel proteins termed TRAPs (thyroid receptor associated proteins). In vitro transcription assays showed that the TR-TRAP complex markedly activates transcription from promoter templates containing TR-binding sites. He has cloned one of the TRAPs (TRAP 220) and found it directly interacts with TR in vivo in a T3-dependent manner. This protein shares significant sequence homology with PBP, a putative co-activator of peroxisome proliferator-activated receptors (PPARs), and RB18A, a novel p53-like co-regulatory protein. The investigator hypothesizes that TRAP 220, alone or in concert with other TRAP subunits, functions as a positive co-activator for gene-specific transcription.
The aims of the proposal are: (1) Characterize TRAP 220 function in terms of ligand- induced interactions with TR and other nuclear hormone receptors (NRs) using deletion and site-directed mutagenesis to define interaction motifs of both TRAP 220 and other NRs using various protein-protein interaction studies and DNA mobility shift assays. (2) Examine the functional relevance of TRAP 220 as a transcriptional co-activator for hormone-dependent activation by TR and other NRs in co-transfection assays and in vitro transcription analyses. (3) Identify the specific cofactors which physically and functionally interact with TRAP 220. He proposes to screen the TR-TRAP complex by far western analysis using TRAP 220 as a probe to identify TRAP 220-interacting factors and a panel of recently cloned TRAP subunits will be screened for TRAP 220 interactions using protein-protein interaction assays. Identified cofactors will be further assayed for in vivo and functional associations with TRAP 220.

Agency
National Institute of Health (NIH)
Institute
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
Type
Research Project (R01)
Project #
5R01DK054030-02
Application #
6138080
Study Section
Endocrinology Study Section (END)
Program Officer
Margolis, Ronald N
Project Start
1999-02-15
Project End
2002-12-30
Budget Start
2000-01-01
Budget End
2000-12-31
Support Year
2
Fiscal Year
2000
Total Cost
$203,544
Indirect Cost
Name
University of Maryland Baltimore
Department
Physiology
Type
Schools of Medicine
DUNS #
003255213
City
Baltimore
State
MD
Country
United States
Zip Code
21201
Pyper, Sean R; Viswakarma, Navin; Jia, Yuzhi et al. (2010) PRIC295, a Nuclear Receptor Coactivator, Identified from PPAR?-Interacting Cofactor Complex. PPAR Res 2010:
Belakavadi, Madesh; Fondell, Joseph D (2010) Cyclin-dependent kinase 8 positively cooperates with Mediator to promote thyroid hormone receptor-dependent transcriptional activation. Mol Cell Biol 30:2437-48
Jin, Feng; Fondell, Joseph D (2009) A novel androgen receptor-binding element modulates Cdc6 transcription in prostate cancer cells during cell-cycle progression. Nucleic Acids Res 37:4826-38
Belakavadi, Madesh; Pandey, Pradeep K; Vijayvargia, Ravi et al. (2008) MED1 phosphorylation promotes its association with mediator: implications for nuclear receptor signaling. Mol Cell Biol 28:3932-42
Vijayvargia, Ravi; May, Michael S; Fondell, Joseph D (2007) A coregulatory role for the mediator complex in prostate cancer cell proliferation and gene expression. Cancer Res 67:4034-41
Udayakumar, T S; Belakavadi, Madesh; Choi, Kyoung-Han et al. (2006) Regulation of Aurora-A kinase gene expression via GABP recruitment of TRAP220/MED1. J Biol Chem 281:14691-9
Pandey, Pradeep K; Udayakumar, T S; Lin, Xinjie et al. (2005) Activation of TRAP/mediator subunit TRAP220/Med1 is regulated by mitogen-activated protein kinase-dependent phosphorylation. Mol Cell Biol 25:10695-710
Sharma, Dipali; Fondell, Joseph D (2002) Ordered recruitment of histone acetyltransferases and the TRAP/Mediator complex to thyroid hormone-responsive promoters in vivo. Proc Natl Acad Sci U S A 99:7934-9
Wang, Q; Fondell, J D (2001) Generation of a mammalian cell line stably expressing a tetracycline-regulated epitope-tagged human androgen receptor: implications for steroid hormone receptor research. Anal Biochem 289:217-30
Sharma, D; Fondell, J D (2000) Temporal formation of distinct thyroid hormone receptor coactivator complexes in HeLa cells. Mol Endocrinol 14:2001-9

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