Noonan syndrome (NS) is an autosomal dominant disorder that occurs with a frequency of ~ 1:2,000 live births. Approximately 50% of NS patients contain a gain-of-function mutation in the human PTPN11 gene which encodes for the SH2 domain-containing protein tyrosine phosphatase, SHP-2. NS patients exhibit a diverse array of clinical manifestations, most notably, congenital heart disease (CHD). CHD occurs in up to 80% of NS patients, making PTPN11/SHP-2 mutations the most common non-chromosomal cause of CHD. Therefore, altered tyrosyl phosphorylation underlies the basis for CHD. The broad goal of this research is to uncover the molecular basis for how NS-associated SHP-2 mutations give rise to CHD. Although much work has established that enhanced activation of the Ras/extracellular signal-regulated kinases 1 and 2 (ERK1/2) pathway is causal to NS-mediated CHD the precise mechanisms through which NS-associated SHP-2 mutations engage in pathophysiological signaling to Ras/ERK1/2 remains unknown. We propose to identify the direct upstream and downstream targets of NS-associated SHP-2 mutants and determine if these targets are involved in the development of NS-mediated CHD. In the first aim, we have identified that NS-associated SHP- 2 mutants interact preferentially with ITIM-containing transmembrane glycoproteins. We hypothesize that dysregulated membrane proximity by NS-associated SHP-2 mutants engages promiscuous dephosphorylation of substrates that evoke Ras/ERK1/2 signaling. The contribution of these ITIM/NS-SHP-2 interactions to signal to Ras/ERK1/2 will be defined. The substrates involved in NS-mediated Ras/ERK1/2 activity will be identified and characterized for their involvement in NS-associated SHP-2 mutant signaling.
In specific aim two, the ITIM containing transmembrane glycoproteins have been identified to be hypertyrosyl phosphorylated in a mouse model of NS. We will identify the NS-induced tyrosine kinase(s) and using a combination of genetic and biochemical approaches determine whether this tyrosine kinase(s) propagates enhanced ERK1/2 activation and subsequently NS-related cardiac defects.
The third aim will test the pathophysiological contribution of altered membrane recruitment of NS-associated SHP-2 mutants as a determinant of NS-mediated cardiac defects. We will accomplish this by employing genetic approaches to interfere with the recruitment of NS- associated SHP-2 to the membrane. The completion of these studies will yield new insight into the direct targets of NS-associated SHP-2 mutants in CHD, and may reveal unanticipated roles, for new and established, signaling molecules in this disease. The identification of targets involved in CHD will also reveal new modes of therapeutic strategies in which to treat, and prognostic tools in which to evaluate, NS-related CHD.

Public Health Relevance

Noonan syndrome (NS) is an autosomal dominant developmental disorder that occurs with a frequency of ~1:2,000 live births in the United States. The cause of NS has been mapped to the PTPN11 gene, which encodes for the SH2 domain-containing protein tyrosine phosphatase-2 (SHP-2). This application seeks to understand the signaling mechanisms through which mutated PTPN11 causes NS-related defects in the heart.

National Institute of Health (NIH)
National Institute of General Medical Sciences (NIGMS)
Research Project (R01)
Project #
Application #
Study Section
Cellular Signaling and Regulatory Systems Study Section (CSRS)
Program Officer
Gaillard, Shawn R
Project Start
Project End
Budget Start
Budget End
Support Year
Fiscal Year
Total Cost
Indirect Cost
Yale University
Schools of Medicine
New Haven
United States
Zip Code
Yi, Jae-Sung; Huang, Yan; Kwaczala, Andrea T et al. (2016) Low-dose dasatinib rescues cardiac function in Noonan syndrome. JCI Insight 1:e90220
Lee, Hojin; Bennett, Anton M (2015) Identification of receptor protein tyrosine phosphatases (RPTPs) as regulators of receptor tyrosine kinases (RTKs) using an RPTP siRNA-RTK substrate screen. Methods Mol Biol 1233:111-20
Lee, Hojin; Yi, Jae-Sung; Lawan, Ahmed et al. (2015) Mining the function of protein tyrosine phosphatases in health and disease. Semin Cell Dev Biol 37:66-72
Paardekooper Overman, Jeroen; Yi, Jae-Sung; Bonetti, Monica et al. (2014) PZR coordinates Shp2 Noonan and LEOPARD syndrome signaling in zebrafish and mice. Mol Cell Biol 34:2874-89
Lawan, Ahmed; Shi, Hao; Gatzke, Florian et al. (2013) Diversity and specificity of the mitogen-activated protein kinase phosphatase-1 functions. Cell Mol Life Sci 70:223-37
Kallen, Amanda N; Zhou, Xiao-Bo; Xu, Jie et al. (2013) The imprinted H19 lncRNA antagonizes let-7 microRNAs. Mol Cell 52:101-12
Mercan, Fatih; Lee, Hojin; Kolli, Sivanagarani et al. (2013) Novel role for SHP-2 in nutrient-responsive control of S6 kinase 1 signaling. Mol Cell Biol 33:293-306
Lee, Hojin; Bennett, Anton M (2013) Receptor protein tyrosine phosphatase-receptor tyrosine kinase substrate screen identifies EphA2 as a target for LAR in cell migration. Mol Cell Biol 33:1430-41
Shi, Hao; Verma, Mayank; Zhang, Lei et al. (2013) Improved regenerative myogenesis and muscular dystrophy in mice lacking Mkp5. J Clin Invest 123:2064-77
Mercan, Fatih; Bennett, Anton M (2010) Analysis of protein tyrosine phosphatases and substrates. Curr Protoc Mol Biol Chapter 18:Unit 18.16