Understanding the pathogenesis of cell cycle diseases (e.g., cancer) is complex due to the multiplicity of protein-protein interactions that must be considered. The view of protein-protein interactions as highly inter-connected networks embraces this complexity at the outset, and holds out the promise for the discovery of new therapeutic targets and strategies. To realize this promise, we must understand how key network proteins - modular signaling proteins - drive cellular signal transduction. Mounting evidence shows that these proteins have significant conformational dynamics that change upon target binding. This suggests a functional link between network signaling and protein motion. Yet, most analyses of protein interaction networks implicitly assume static structures. Hence, defining the influence of conformational dynamics on signaling within protein-protein interaction networks remains an outstanding challenge in biology. The goal of our proposed research is to deepen our understanding of how the functional motions of modular signaling proteins affects normal versus pathogenic network signaling, and eventually suggest new strategies for the design of ligands targeting dynamic modular proteins. Toward this goal, we explore two hypotheses developed from our recent work: (1) modular signaling proteins vary the sequences of their recognition loops to enhance binding preference;this has implications for interaction diversity and signal routing within the network;(2) modular signaling proteins use inter-domain interactions to stimulate changes in dynamics that allosterically modulate catalytic activity;this has implications for the mechanisms by which individual proteins process chemical signals. To investigate these hypotheses, we propose NMR investigations of dynamics-activity relationships in a model protein, human Pin1. Pin1 is a mitotic regulator consisting of a docking module (WW domain) flexibly linked to a catalytic module (isomerase domain), and is a current cancer target. Its robust biochemical properties make it an excellent model system for exploring fundamental properties of modular proteins. Investigations will use full-length Pin1, its isolated domains, and known Pin1 substrates/inhibitors.

Public Health Relevance

This proposal describes studies of a model system to understand how intrinsic protein dynamics enable biological networks to maintain cell survival and growth. The proposed research will provide new insights into the molecular origins of disease.

National Institute of Health (NIH)
National Institute of General Medical Sciences (NIGMS)
Research Project (R01)
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Macromolecular Structure and Function C Study Section (MSFC)
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Wehrle, Janna P
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University of Notre Dame
Schools of Arts and Sciences
Notre Dame
United States
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Wang, Xingsheng; Mahoney, Brendan J; Zhang, Meiling et al. (2015) Negative Regulation of Peptidyl-Prolyl Isomerase Activity by Interdomain Contact in Human Pin1. Structure 23:2224-33
Peng, Jeffrey W (2015) Investigating Dynamic Interdomain Allostery in Pin1. Biophys Rev 7:239-249
Mercedes-Camacho, Ana Y; Mullins, Ashley B; Mason, Matthew D et al. (2013) Kinetic isotope effects support the twisted amide mechanism of Pin1 peptidyl-prolyl isomerase. Biochemistry 52:7707-13
Wilson, Kimberly A; Bouchard, Jill J; Peng, Jeffrey W (2013) Interdomain interactions support interdomain communication in human Pin1. Biochemistry 52:6968-81
Peng, J W (2012) Exposing the Moving Parts of Proteins with NMR Spectroscopy. J Phys Chem Lett 3:1039-1051
Namanja, Andrew T; Wang, Xiaodong J; Xu, Bailing et al. (2011) Stereospecific gating of functional motions in Pin1. Proc Natl Acad Sci U S A 108:12289-94
Morcos, Faruck; Chatterjee, Santanu; McClendon, Christopher L et al. (2010) Modeling conformational ensembles of slow functional motions in Pin1-WW. PLoS Comput Biol 6:e1001015
Namanja, Andrew T; Wang, Xiaodong J; Xu, Bailing et al. (2010) Toward flexibility-activity relationships by NMR spectroscopy: dynamics of Pin1 ligands. J Am Chem Soc 132:5607-9
Peng, Jeffrey W; Wilson, Brian D; Namanja, Andrew T (2009) Mapping the dynamics of ligand reorganization via 13CH3 and 13CH2 relaxation dispersion at natural abundance. J Biomol NMR 45:171-83
Zintsmaster, John S; Wilson, Brian D; Peng, Jeffrey W (2008) Dynamics of ligand binding from 13C NMR relaxation dispersion at natural abundance. J Am Chem Soc 130:14060-1