Noonan Syndrome/Leukemia-associated Gain-of-function Mutations in SHP-2 Phosphatase (PTPN11) Enhance Cell Migration and Angiogenesis

Wang, Siying; Yu, Wen Mei; Zhang, Wanming; McCrae, Keith R.; Neel, Benjamin G.; Qu, Cheng Kui

doi:10.1074/jbc.m804129200

Cited by 37 publications

(23 citation statements)

References 43 publications

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“…As a result of the accelerated cycling, the percentage of quiescent stem cells at the G 0 phase was decreased (Figure 2A-B). Alternatively, increased mobilization of Ptpn11 D61G/ϩ mutant cells 43 could also contribute to the lower abundance of quiescent stem cells. Activation of stem cells usually leads to a decrease in the stem cell pool due to exhaustion of the reserve capacity.…”

Section: Discussionmentioning

confidence: 99%

A germline gain-of-function mutation in Ptpn11 (Shp-2) phosphatase induces myeloproliferative disease by aberrant activation of hematopoietic stem cells

Wang

et al. 2010

Blood

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Germline and somatic gain-of-function mutations in tyrosine phosphatase PTPN11 (SHP-2) are associated with juvenile myelomonocytic leukemia (JMML), a myeloproliferative disease (MPD) of early childhood. The mechanism by which PTPN11 mutations induce this disease is not fully understood. Signaling partners that mediate the pathogenic effects of PTPN11 mutations have not been explored. Here we report that germ line mutation Ptpn11 D61G in mice aberrantly accelerates hematopoietic stem cell (HSC) cycling, increases the stem cell pool, and elevates short-term and long-term repopulating capabilities, leading to the development of MPD. MPD is reproduced in primary and secondary recipient mice transplanted with Ptpn11 D61G/؉ whole bone marrow cells or purified Lineage ؊ Sca-1 ؉ c-Kit ؉ cells, but not lineage committed progenitors. The deleterious effects of Ptpn11 D61G mutation on HSCs are attributable to enhancing cytokine/growth factor signaling. The aberrant HSC activities caused by Ptpn11 D61G mutation are largely corrected by deletion of Gab2, a prominent interacting protein and target of Shp-2 in cell signaling. As a result, MPD phenotypes are markedly ameliorated in Ptpn11 D61G/؉ / Gab2 ؊/؊ double mutant mice. Collectively, our data suggest that oncogenic Ptpn11 induces MPD by aberrant activation of HSCs. This study also identifies Gab2 as an important mediator for the pathogenic effects of Ptpn11 mutations. (Blood. 2010;116(18): 3611-3621) IntroductionJuvenile myelomonocytic leukemia (JMML), a myeloproliferative disease (MPD) of young children characterized by cytokine hypersensitivity of myeloid progenitors, is associated with mutations in the rat sarcoma viral oncogene (RAS) pathway. 1,2 Thirtyfive percent of patients with JMML have activating mutations in tyrosine phosphatase PTPN11 (SHP-2), a known positive regulator of the Ras pathway (see next paragraph), while activating mutations in RAS (N-RAS or K-RAS) and homozygous inactivation of NF1, a GTPase activating protein that negatively regulates RAS output, account for 20% and 15% of JMML cases, respectively. 1,2 More recently, loss-of-function mutations in a E3 ubiquitin ligase c-CBL have been identified in 10%-15% of patients with JMML. 3,4 PTPN11, RAS, NF1, and c-CBL mutations are usually mutually exclusive in patients. Remarkably, mutations in these genes play a causal role in the pathogenesis of JMML. Single disease mutations, such as Ptpn11 D61G/Y , K-Ras G12D , Nf1 deficiency, and Cbl deficiency, are necessary and sufficient to induce cytokine hypersensitivity in myeloid progenitors and JMML-like MPD in mice. [5][6][7][8][9][10][11][12] Ptpn11 (Shp-2), a ubiquitously expressed protein tyrosine phosphatase, is involved in multiple cell signaling processes, such as the RAS-MAP kinase, JAK/STAT, PI3K/AKT, NF-B, and NFAT pathways. [13][14][15] Intriguingly, despite its direct function in protein dephosphorylation, Shp-2 generally plays a positive role in transducing signals initiated from receptor and cytosolic kinases. This is particularly the case for ...

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Section: Discussionmentioning

confidence: 99%

A germline gain-of-function mutation in Ptpn11 (Shp-2) phosphatase induces myeloproliferative disease by aberrant activation of hematopoietic stem cells

Wang

et al. 2010

Blood

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“…The importance of SHP-2 in vivo is evident by the fact that the loss of expression of functional SHP-2 in developing mice results in death between days 8.5-10.5 of gestation. These fetuses display multiple defects in mesodermal patterning as well as impaired hematopoietic development in embryonic stem cells (43,44,48). In addition, genetic mutations in PTPN11 that cause hyperactivation of SHP-2 phosphatase activity have been identified in the Noonan syndrome, a human developmental disorder (43,48), and in various childhood leukemias (29,44).…”

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SHP-2 phosphatase activity is required for PECAM-1-dependent cell motility

Zhu

Cao

Williams

et al. 2010

American Journal of Physiology-Cell Physiology

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Platelet endothelial cell adhesion molecule-1 (PECAM-1) has been implicated in endothelial cell motility during angiogenesis. Although there is evidence that SHP-2 plays a role in PECAM-1-dependent cell motility, the molecular basis of the activity of SHP-2 in this process has not been defined. To investigate the requirement of SHP-2 in PECAM-1-dependent cell motility, studies were done in which various constructs of SHP-2 were expressed in cell transfectants expressing PECAM-1. We observed that the levels of PECAM-1 tyrosine phosphorylation and SHP-2 association with PECAM-1 were significantly increased in cells expressing a phosphatase-inactive SHP-2 mutant, suggesting that the level of PECAM-1 tyrosine phosphorylation, and thus SHP-2 binding are regulated in part by bound, catalytically active SHP-2. We subsequently found that expression of PECAM-1 stimulated wound-induced migration and the formation of filopodia (a morphological feature of motile cells). These activities were associated with increased mitogen-activated protein kinase (MAPK) activation and the dephosphorylation of paxillin (an event implicated in the activation of MAPK). The phosphatase-inactive SHP-2 mutant, however, suppressed these PECAM-1-dependent phenomena, whereas the activity of PECAM-1 expressing cells was not altered by expression of wild-type SHP-2 or SHP-2 in which the scaffold/adaptor function had been disabled. Pharmacological inhibition of SHP-2 phosphatase activity also suppressed PECAM-1-dependent motility. Furthermore, PECAM-1 expression also stimulates tube formation, but none of the SHP-2 constructs affected this process. These findings therefore suggest a model for the involvement of SHP-2 in PECAM-1-dependent motility in which SHP-2, recruited by its interaction with PECAM-1, targets paxillin to ultimately activate the MAPK pathway and downstream events required for cell motility.

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“…It is now well accepted that NS mutants can exert a dominant-positive effect on Ras-MAPK activation and that this upregulation is responsible for the cardiac defects observed in NS (1,2,9,11,22,23,29). In addition, NS mutations could alter other signaling pathways (Ca 2ϩ /NFAT, RhoA, and Src) (17,42,44). In the case of PTPN11 mutations causing LS, our knowledge is much poorer, since even the outcomes of these mutations for the Ras-MAPK pathway are unclear (21,31).…”

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Functional Effects of PTPN11 (SHP2) Mutations Causing LEOPARD Syndrome on Epidermal Growth Factor-Induced Phosphoinositide 3-Kinase/AKT/Glycogen Synthase Kinase 3β Signaling

Edouard

Combier

Nédélec

et al. 2010

Molecular and Cellular Biology

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LEOPARD syndrome (LS), a disorder with multiple developmental abnormalities, is mainly due to mutations that impair the activity of the tyrosine phosphatase SHP2 (PTPN11). How these alterations cause the disease remains unknown. We report here that fibroblasts isolated from LS patients displayed stronger epidermal growth factor (EGF)-induced phosphorylation of both AKT and glycogen synthase kinase 3␤ (GSK-3␤) than fibroblasts from control patients. Similar results were obtained in HEK293 cells expressing LS mutants of SHP2. We found that the GAB1/phosphoinositide 3-kinase (PI3K) complex was more abundant in fibroblasts from LS than control subjects and that both AKT and GSK-3␤ hyperphosphorylation were prevented by reducing GAB1 expression or by overexpressing a GAB1 mutant unable to bind to PI3K. Consistently, purified recombinant LS mutants failed to dephosphorylate GAB1 PI3K-binding sites. These mutants induced PI3K-dependent increase in cell size in a model of chicken embryo cardiac explants and in transcriptional activity of the atrial natriuretic factor (ANF) gene in neonate rat cardiomyocytes. In conclusion, SHP2 mutations causing LS facilitate EGF-induced PI3K/AKT/GSK-3␤ stimulation through impaired GAB1 dephosphorylation, resulting in deregulation of a novel signaling pathway that could be involved in LS pathology.Noonan syndrome (NS) (MIM163950) is a relatively frequent (ϳ1/2,000 births) autosomal dominant disease primarily characterized by facial dysmorphism, heart defects, and short stature. LEOPARD syndrome (LS) (MIM151100) is a rarer but related disorder that associates, roughly, NS symptoms with deafness and cutaneous abnormalities. Both NS and LS belong to the family of "neuro-cardio-facial-cutaneous" (NCFC) syndromes, a group of developmental disorders that display different combinations of the above-mentioned symptoms with mental retardation and tumor predisposition (4, 13).At least 80% of LS and 50% of NS patients carry germ line missense mutations in PTPN11, the gene encoding SHP2. SHP2 is a widely expressed protein tyrosine phosphatase (PTP) that contains Src homology 2 (SH2) domains and promotes Rasmitogen-activated protein kinase (MAPK) activation through different molecular mechanisms (14,27,39,47). Other LS or NS forms are caused by mutations in KRAS, SOS1, RAF1, BRAF, and SHOC2 genes, which encode key factors of the Ras-MAPK pathway (6,32,34,37,38,41).Although genetic studies have provided essential advances, how PTPN11 mutations cause the diseases' symptoms remains an open question. Biochemical studies have shown that NS mutations are located at contact points between the catalytic and the SH2 domains and therefore disrupt SHP2 autoinhibitory conformation (11,19), thereby stimulating SHP2 catalytic activity (gain-of-function mutations). Conversely, LS mutations are confined within the catalytic domain and repress SHP2 activity (15,21,40).A key issue in understanding LS/NS pathogenesis is the identification of the signaling pathways that are altered by these mutations. It is now well ac...

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Noonan Syndrome/Leukemia-associated Gain-of-function Mutations in SHP-2 Phosphatase (PTPN11) Enhance Cell Migration and Angiogenesis

Cited by 37 publications

References 43 publications

A germline gain-of-function mutation in Ptpn11 (Shp-2) phosphatase induces myeloproliferative disease by aberrant activation of hematopoietic stem cells

A germline gain-of-function mutation in Ptpn11 (Shp-2) phosphatase induces myeloproliferative disease by aberrant activation of hematopoietic stem cells

SHP-2 phosphatase activity is required for PECAM-1-dependent cell motility

Functional Effects of PTPN11 (SHP2) Mutations Causing LEOPARD Syndrome on Epidermal Growth Factor-Induced Phosphoinositide 3-Kinase/AKT/Glycogen Synthase Kinase 3β Signaling

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