The objective of the proposed studies is to investigate the molecular mechanisms underlying the specific regulatory and targeting interactions of the Wnt signaling pathways by using structural and biophysical methods. Wnt signaling plays an important role in embryonic development and in the regulation of cell growth. Inappropriate activation of Wnt signaling has been implicated in cancers and other human diseases. Dishevelled (Dvl), an important component of the Wnt signaling pathways, relays signals from the membrane-bound Wnt receptor Frizzled (Fz) to downstream partners. Different Wnt signaling pathways diverge at the level of Dvl. However, the mechanism by which Dvl transduces the Wnt signals is unclear, as are the molecular events that regulate pathway specification at the level of Dvl. The proposed structural and biophysical analyses will address these questions by elucidating the fundamental chemical nature of the interactions between Dvl and its binding partners. Dvl is hypothesized to undergo conformational changes upon receiving Wnt signals. Protein NMR spectroscopy will be used to investigate these conformational changes and the mechanism of their regulation by molecular interactions of Dvl and its binding molecules.
The Specific Aims are to 1) Determine the binding specificities between the PDZ domains of Dvl proteins and the C-termini of Fz receptors by protein NMR spectroscopy and other physical biochemistry methods;2) Identify components of the regulatory network that mediates the function of the Dvl proteins;and 3) Ascertain whether Dvl undergoes a conformational change in the transduction of Wnt signaling. The knowledge gained from these investigations will not only help to explain the fundamental chemical nature of the complex molecular interplay at the level of Dvl in Wnt signaling but will also shed light on the maintenance of intracellular signal specificity and the nature of global signaling control. These findings may also be useful in formulating rational approaches to the development of novel pharmaceutical agents that can interfere with specific Wnt signaling events that contribute to human diseases.

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Research Project (R01)
Project #
5R01GM081492-03
Application #
7628675
Study Section
Macromolecular Structure and Function C Study Section (MSFC)
Program Officer
Flicker, Paula F
Project Start
2007-08-01
Project End
2011-05-31
Budget Start
2009-06-01
Budget End
2010-05-31
Support Year
3
Fiscal Year
2009
Total Cost
$310,800
Indirect Cost
Name
St. Jude Children's Research Hospital
Department
Type
DUNS #
067717892
City
Memphis
State
TN
Country
United States
Zip Code
38105
Bao, Ju; Marathe, Bindumadhav; Govorkova, Elena A et al. (2016) Drug Repurposing Identifies Inhibitors of Oseltamivir-Resistant Influenza Viruses. Angew Chem Int Ed Engl 55:3438-41
Lee, Ho-Jin; Bao, Ju; Miller, Ami et al. (2015) Structure-based Discovery of Novel Small Molecule Wnt Signaling Inhibitors by Targeting the Cysteine-rich Domain of Frizzled. J Biol Chem 290:30596-606
Lee, Ho-Jin; Shi, De-Li; Zheng, Jie J (2015) Conformational change of Dishevelled plays a key regulatory role in the Wnt signaling pathways. Elife 4:e08142
Rana, Rajashree; Carroll, Candace E; Lee, Ho-Jin et al. (2013) Structural insights into the role of the Smoothened cysteine-rich domain in Hedgehog signalling. Nat Commun 4:2965
Bao, Ju; Lee, Ho-Jin; Zheng, Jie J (2013) Genome-wide network analysis of Wnt signaling in three pediatric cancers. Sci Rep 3:2969
Cheepala, Satish B; Bao, Ju; Nachagari, Deepa et al. (2013) Crucial role for phylogenetically conserved cytoplasmic loop 3 in ABCC4 protein expression. J Biol Chem 288:22207-18
Li, Xiaofeng; Shan, Jufang; Chang, Woochul et al. (2012) Chemical and genetic evidence for the involvement of Wnt antagonist Dickkopf2 in regulation of glucose metabolism. Proc Natl Acad Sci U S A 109:11402-7
Shan, Jufang; Zhang, Xinxin; Bao, Ju et al. (2012) Synthesis of potent dishevelled PDZ domain inhibitors guided by virtual screening and NMR studies. Chem Biol Drug Des 79:376-83
Shan, Jufang; Zheng, Jie J (2012) Virtual ligand screening combined with NMR to identify Dvl PDZ domain inhibitors targeting the Wnt signaling. Methods Mol Biol 928:17-28
Bao, Ju; Zheng, Jie J; Wu, Dianqing (2012) The structural basis of DKK-mediated inhibition of Wnt/LRP signaling. Sci Signal 5:pe22

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