The long-term objectives of this research program are to characterize the structure and function of protein tyrosine phosphatases (PTPs). The PTPs constitute a large family of signaling enzymes that together with protein tyrosine kinases (PTKs) modulate the cellular level of tyrosine phosphorylation. Disturbance of the normal balance between PTK and PTP activity results in aberrant tyrosine phosphorylation, which has been linked to the etiology of several human diseases, including cancer. Thus, a complete understanding of the physiological roles of protein tyrosine phosphorylation and how this process is deregulated in human diseases must necessarily encompass the characterization of PTPs. Such understanding may lead to the development of novel therapeutics that selectively target elements of signaling pathways for the treatment of human diseases. This competitive renewal focuses on SHP2 (Src homology 2 (SH2)-domain containing protein tyrosine phosphatase-2), which is the first bona fide oncoprotein identified in the PTP superfamily. SHP2 is ubiquitously expressed and positively regulates signaling from receptor tyrosine kinases through the activation of the Ras/ERK1/2 cascade. Consistent with its oncogenic role, germline autosomal dominant SHP2 mutations cause clinically similar LEOPARD syndrome (LS) and Noonan syndrome (NS), both of which are associated with increased risk of malignancy. In addition, somatic SHP2 mutations contribute to many forms of leukemia and solid tumors. However, although SHP2 mutations are associated with a number of developmental and neoplastic disorders, it remains unclear how SHP2 mutations alter cellular signaling to produce disease phenotypes. For example, NS or neoplasia-associated SHP2 mutants are constitutively active, resulting in gain-of-function effects. In contrast, mutations associated with LS reduce SHP2 phosphatase activity. These findings generated an enigma: how do SHP2 mutations with opposite effects elicit overlapping phenotypes? We hypothesize that pathogenic SHP2 mutations alter not only SHP2 phosphatase activity but also its molecular switching mechanism to drive disease outcomes and thus detailed understanding of the structure and function of SHP2 will reveal critical signaling events that underlie the diseases. The goals of this project ar to understand the molecular basis of disease-associated SHP2 mutations and to define the chain of molecular events coupling SHP2 dysfunction to the various LS abnormalities. A multidisciplinary approach, involving innovative combinations of X-ray crystallography, mass spectrometry, combinatorial chemistry, site-directed mutagenesis, enzyme kinetics, and cell biology will be employed to: 1) characterize the structural and biochemical properties of the LS mutants, and 2) define the signaling mechanisms mediated by the LS mutants. Successful completion of this project will create a solid framework for understanding how individual SHP2 mutations cause diseases and provide insight into novel points of therapeutic intervention for these diseases.

Public Health Relevance

This project is focused on the oncogenic protein tyrosine phosphatase SHP2. SHP2 mutations are known to cause a number of developmental disorders associated with increased risk of malignancy, multiple forms of leukemia, and solid tumors. This work will characterize the structural and biochemical properties of SHP2 mutants and define the mechanisms by which genetic mutations in SHP2 lead to various diseases.

Agency
National Institute of Health (NIH)
Institute
National Cancer Institute (NCI)
Type
Research Project (R01)
Project #
5R01CA069202-18
Application #
8602512
Study Section
Macromolecular Structure and Function E Study Section (MSFE)
Program Officer
Knowlton, John R
Project Start
1996-07-01
Project End
2017-11-30
Budget Start
2013-12-01
Budget End
2014-11-30
Support Year
18
Fiscal Year
2014
Total Cost
$271,634
Indirect Cost
$97,510
Name
Indiana University-Purdue University at Indianapolis
Department
Biochemistry
Type
Schools of Medicine
DUNS #
603007902
City
Indianapolis
State
IN
Country
United States
Zip Code
46202
Ruddraraju, Kasi Viswanatharaju; Zhang, Zhong-Yin (2017) Covalent inhibition of protein tyrosine phosphatases. Mol Biosyst 13:1257-1279
Kobayashi, M; Bai, Y; Chen, S et al. (2017) Phosphatase PRL2 promotes oncogenic NOTCH1-Induced T-cell leukemia. Leukemia 31:751-754
Kobayashi, M; Chen, S; Bai, Y et al. (2017) Phosphatase PRL2 promotes AML1-ETO-induced acute myeloid leukemia. Leukemia 31:1453-1457
Yamashita, Naoya; Joshi, Rajshri; Zhang, Sheng et al. (2017) Phospho-Regulation of Soma-to-Axon Transcytosis of Neurotrophin Receptors. Dev Cell 42:626-639.e5
Kobayashi, Michihiro; Nabinger, Sarah C; Bai, Yunpeng et al. (2017) Protein Tyrosine Phosphatase PRL2 Mediates Notch and Kit Signals in Early T Cell Progenitors. Stem Cells 35:1053-1064
Sacchetti, Cristiano; Bai, Yunpeng; Stanford, Stephanie M et al. (2017) PTP4A1 promotes TGF? signaling and fibrosis in systemic sclerosis. Nat Commun 8:1060
Bai, Yunpeng; Zhou, Hong-Ming; Zhang, Lujuan et al. (2016) Role of phosphatase of regenerating liver 1 (PRL1) in spermatogenesis. Sci Rep 6:34211
Wang, Jianxun; Mizui, Masayuki; Zeng, Li-Fan et al. (2016) Inhibition of SHP2 ameliorates the pathogenesis of systemic lupus erythematosus. J Clin Invest 126:2077-92
Maeshima, Keisuke; Stanford, Stephanie M; Hammaker, Deepa et al. (2016) Abnormal PTPN11 enhancer methylation promotes rheumatoid arthritis fibroblast-like synoviocyte aggressiveness and joint inflammation. JCI Insight 1:
Hamerman, Jessica A; Pottle, Jessica; Ni, Minjian et al. (2016) Negative regulation of TLR signaling in myeloid cells--implications for autoimmune diseases. Immunol Rev 269:212-27

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