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Pugliese A, Della Marina A, de Paula Estephan E, Zanoteli E, Roos A, Schara-Schmidt U, Hentschel A, Azuma Y, Töpf A, Thompson R, Polavarapu K, Lochmüller H. Mutations in PTPN11 could lead to a congenital myasthenic syndrome phenotype: a Noonan syndrome case series. J Neurol 2024; 271:1331-1341. [PMID: 37923938 DOI: 10.1007/s00415-023-12070-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2023] [Revised: 10/12/2023] [Accepted: 10/13/2023] [Indexed: 11/06/2023]
Abstract
The RASopathies are a group of genetic rare diseases caused by mutations affecting genes involved in the RAS/MAPK (RAS-mitogen activated protein kinase) pathway. Among them, PTPN11 pathogenic variants are responsible for approximately 50% of Noonan syndrome (NS) cases and, albeit to a lesser extent, of Leopard syndrome (LPRD1), which present a few overlapping clinical features, such as facial dysmorphism, developmental delay, cardiac defects, and skeletal deformities. Motor impairment and decreased muscle strength have been recently reported. The etiology of the muscle involvement in these disorders is still not clear but probably multifactorial, considering the role of the RAS/MAPK pathway in skeletal muscle development and Acetylcholine Receptors (AChR) clustering at the neuromuscular junction (NMJ). We report, herein, four unrelated children carrying three different heterozygous mutations in the PTPN11 gene. Intriguingly, their phenotypic features first led to a clinical suspicion of congenital myasthenic syndrome (CMS), due to exercise-induced fatigability with a variable degree of muscle weakness, and serum proteomic profiling compatible with a NMJ defect. Moreover, muscle fatigue improved after treatment with CMS-specific medication. Although the link between PTPN11 gene and neuromuscular transmission is unconfirmed, an increasing number of patients with RASopathies are affected by muscle weakness and fatigability. Hence, NS or LPDR1 should be considered in children with suspected CMS but negative genetic workup for known CMS genes or additional symptoms indicative of NS, such as facial dysmorphism or intellectual disability.
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Affiliation(s)
- Alessia Pugliese
- IRCCS Centro Neurolesi "Bonino Pulejo", Messina, Italy
- Children's Hospital of Eastern Ontario Research Institute, 401 Smyth Rd., Ottawa, ON, K1H 8L1, Canada
| | - Adela Della Marina
- Department of Pediatric Neurology, Centre for Neuromuscular Disorders, Centre for Translational Neuro- and Behavioral Sciences, University Duisburg-Essen, 45147, Essen, Germany
| | - Eduardo de Paula Estephan
- Department of Neurology, Faculdade de Medicina da Universidade de São Paulo (FMUSP), São Paulo, Brazil
- Department of Neurological Sciences, Psychiatry, and Medical Psychology, Sao Jose do Rio Preto State Medical School, Sao Jose do Rio Preto, São Paulo, Brazil
| | - Edmar Zanoteli
- Department of Neurology, Faculdade de Medicina da Universidade de São Paulo (FMUSP), São Paulo, Brazil
| | - Andreas Roos
- Children's Hospital of Eastern Ontario Research Institute, 401 Smyth Rd., Ottawa, ON, K1H 8L1, Canada
- Department of Pediatric Neurology, Centre for Neuromuscular Disorders, Centre for Translational Neuro- and Behavioral Sciences, University Duisburg-Essen, 45147, Essen, Germany
- Department of Neurology, Heimer Institute for Muscle Research, University Hospital Bergmannsheil, Ruhr-University Bochum, 44789, Bochum, Germany
- Leibniz-Institut Für Analytische Wissenschaften-ISAS-e.V., 44227, Dortmund, Germany
| | - Ulrike Schara-Schmidt
- Department of Pediatric Neurology, Centre for Neuromuscular Disorders, Centre for Translational Neuro- and Behavioral Sciences, University Duisburg-Essen, 45147, Essen, Germany
| | - Andreas Hentschel
- Leibniz-Institut Für Analytische Wissenschaften-ISAS-e.V., 44227, Dortmund, Germany
| | - Yoshiteru Azuma
- Department of Human Genetics, Yokohama City University Graduate School of Medicine, Yokohama, Kanagawa, Japan
| | - Ana Töpf
- John Walton Muscular Dystrophy Research Centre, Translational and Clinical Research Institute, University of Newcastle, Newcastle Upon Tyne, UK
| | - Rachel Thompson
- Children's Hospital of Eastern Ontario Research Institute, 401 Smyth Rd., Ottawa, ON, K1H 8L1, Canada
| | - Kiran Polavarapu
- Children's Hospital of Eastern Ontario Research Institute, 401 Smyth Rd., Ottawa, ON, K1H 8L1, Canada
| | - Hanns Lochmüller
- Children's Hospital of Eastern Ontario Research Institute, 401 Smyth Rd., Ottawa, ON, K1H 8L1, Canada.
- Division of Neurology, Department of Medicine, The Ottawa Hospital, Ottawa, Canada.
- Brain and Mind Research Institute, University of Ottawa, Ottawa, Canada.
- Department of Neuropediatrics and Muscle Disorders, Faculty of Medicine, Medical Center-University of Freiburg, Freiburg, Germany.
- Centro Nacional de Análisis Genómico (CNAG), Barcelona, Catalonia, Spain.
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Quilang RC, Lui S, Forbes K. miR-514a-3p: a novel SHP-2 regulatory miRNA that modulates human cytotrophoblast proliferation. J Mol Endocrinol 2022; 68:99-110. [PMID: 34792485 PMCID: PMC8789026 DOI: 10.1530/jme-21-0175] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/04/2021] [Accepted: 11/18/2021] [Indexed: 11/08/2022]
Abstract
Src homology-2 domain-containing protein tyrosine phosphatase 2 (SHP-2), encoded by the PTPN11 gene, forms a central component of multiple signalling pathways and is required for insulin-like growth factor (IGF)-induced placental growth. Altered expression of SHP-2 is associated with aberrant placental and fetal growth indicating that drugs modulating SHP-2 expression may improve adverse pregnancy outcome associated with altered placental growth. We have previously demonstrated that placental PTPN11/SHP-2 expression is controlled by miRNAs. SHP-2 regulatory miRNAs may have therapeutic potential; however, the individual miRNA(s) that regulate SHP-2 expression in the placenta remain to be established. We performed in silico analysis of 3'UTR target prediction databases to identify libraries of Hela cells transfected with individual miRNA mimetics, enriched in potential SHP-2 regulatory miRNAs. Analysis of PTPN11 levels by quantitative (q) PCR revealed that miR-758-3p increased, while miR-514a-3p reduced PTPN11 expression. The expression of miR-514a-3p and miR-758-3p within the human placenta was confirmed by qPCR; miR-514a-3p (but not miR-758-3p) levels inversely correlated with PTPN11 expression. To assess the interaction between these miRNAs and PTPN11/SHP-2, specific mimetics were transfected into first-trimester human placental explants and then cultured for up to 4 days. Overexpression of miR-514a-3p, but not miR-758-3p, significantly reduced PTPN11 and SHP-2 expression. microRNA-ribonucleoprotein complex (miRNP)-associated mRNA assays confirmed that this interaction was direct. miR-514a-3p overexpression attenuated IGF-I-induced trophoblast proliferation (BrdU incorporation). miR-758-3p did not alter trophoblast proliferation. These data demonstrate that by modulating SHP-2 expression, miR-514a-3p is a novel regulator of IGF signalling and proliferation in the human placenta and may have therapeutic potential in pregnancies complicated by altered placental growth.
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Affiliation(s)
- Rachel C Quilang
- Leeds Institute of Cardiovascular and Metabolic Medicine, Faculty of Medicine and Health, University of Leeds, Leeds, UK
| | - Sylvia Lui
- Maternal and Fetal Health Research Centre, Division of Developmental Biology and Medicine, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, UK
- St. Mary’s Hospital, Central Manchester University Hospitals NHS Foundation Trust, Manchester Academic Health Science Centre, Manchester, UK
| | - Karen Forbes
- Leeds Institute of Cardiovascular and Metabolic Medicine, Faculty of Medicine and Health, University of Leeds, Leeds, UK
- Maternal and Fetal Health Research Centre, Division of Developmental Biology and Medicine, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, UK
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Ruzzi LR, Schilman PE, San Martin A, Lew SE, Gelb BD, Pagani MR. The Phosphatase CSW Controls Life Span by Insulin Signaling and Metabolism Throughout Adult Life in Drosophila. Front Genet 2020; 11:364. [PMID: 32457793 PMCID: PMC7221067 DOI: 10.3389/fgene.2020.00364] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2019] [Accepted: 03/25/2020] [Indexed: 11/30/2022] Open
Abstract
Noonan syndrome and related disorders are caused by mutations in genes encoding for proteins of the RAS-ERK1/2 signaling pathway, which affect development by enhanced ERK1/2 activity. However, the mutations’ effects throughout adult life are unclear. In this study, we identify that the protein most commonly affected in Noonan syndrome, the phosphatase SHP2, known in Drosophila as corkscrew (CSW), controls life span, triglyceride levels, and metabolism without affecting ERK signaling pathway. We found that CSW loss-of-function mutations extended life span by interacting with components of the insulin signaling pathway and impairing AKT activity in adult flies. By expressing csw-RNAi in different organs, we determined that CSW extended life span by acting in organs that regulate energy availability, including gut, fat body and neurons. In contrast to that in control animals, loss of CSW leads to reduced homeostasis in metabolic rate during activity. Clinically relevant gain-of-function csw allele reduced life span, when expressed in fat body, but not in other tissues. However, overexpression of a wild-type allele did not affect life span, showing a specific effect of the gain-of-function allele independently of a gene dosage effect. We concluded that CSW normally regulates life span and that mutations in SHP2 are expected to have critical effects throughout life by insulin-dependent mechanisms in addition to the well-known RAS-ERK1/2-dependent developmental alterations.
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Affiliation(s)
- Leonardo R Ruzzi
- Department of Physiology and Biophysics, School of Medicine, National Scientific and Technical Research Council, University of Buenos Aires, Buenos Aires, Argentina
| | - Pablo E Schilman
- Department of Biodiversity and Experimental Biology, Faculty of Exact and Natural Sciences, National Scientific and Technical Research Council, University of Buenos Aires, Buenos Aires, Argentina
| | - Alvaro San Martin
- Department of Physiology and Biophysics, School of Medicine, National Scientific and Technical Research Council, University of Buenos Aires, Buenos Aires, Argentina
| | - Sergio E Lew
- Institute of Biomedical Engineering, Faculty of Engineering, University of Buenos Aires, Buenos Aires, Argentina
| | - Bruce D Gelb
- Mindich Child Health and Development Institute, Icahn School of Medicine at Mount Sinai, New York, NY, United States.,Department of Pediatrics, Icahn School of Medicine at Mount Sinai, New York, NY, United States.,Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, United States
| | - Mario R Pagani
- Department of Physiology and Biophysics, School of Medicine, National Scientific and Technical Research Council, University of Buenos Aires, Buenos Aires, Argentina
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Wang L, Iorio C, Yan K, Yang H, Takeshita S, Kang S, Neel BG, Yang W. A ERK/RSK-mediated negative feedback loop regulates M-CSF-evoked PI3K/AKT activation in macrophages. FASEB J 2018; 32:875-887. [PMID: 29046360 PMCID: PMC5888401 DOI: 10.1096/fj.201700672rr] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2017] [Accepted: 10/02/2017] [Indexed: 12/20/2022]
Abstract
Activation of the RAS/ERK and its downstream signaling components is essential for growth factor-induced cell survival, proliferation, and differentiation. The Src homology-2 domain containing protein tyrosine phosphatase 2 (SHP2), encoded by protein tyrosine phosphatase, non-receptor type 11 ( Ptpn11), is a positive mediator required for most, if not all, receptor tyrosine kinase-evoked RAS/ERK activation, but differentially regulates the PI3K/AKT signaling cascade in various cellular contexts. The precise mechanisms underlying the differential effects of SHP2 deficiency on the PI3K pathway remain unclear. We found that mice with myelomonocytic cell-specific [ Tg(LysM-Cre); Ptpn11fl/fl mice] Ptpn11 deficiency exhibit mild osteopetrosis. SHP2-deficient bone marrow macrophages (BMMs) showed decreased proliferation in response to M-CSF and decreased osteoclast generation. M-CSF-evoked ERK1/2 activation was decreased, whereas AKT activation was enhanced in SHP2-deficient BMMs. ERK1/2, via its downstream target RSK2, mediates this negative feedback by negatively regulating phosphorylation of M-CSF receptor at Tyr721 and, consequently, its binding to p85 subunit of PI3K and PI3K activation. Pharmacologic inhibition of RSK or ERK phenotypically mimics the signaling defects observed in SHP2-deficient BMMs. Furthermore, this increase in PI3K/AKT activation enables BMM survival in the setting of SHP2 deficiency.-Wang, L., Iorio, C., Yan, K., Yang, H., Takeshita, S., Kang, S., Neel, B.G., Yang, W. An ERK/RSK-mediated negative feedback loop regulates M-CSF-evoked PI3K/AKT activation in macrophages.
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Affiliation(s)
- Lijun Wang
- Department of Orthopaedics, Brown University Alpert Medical School, Rhode Island Hospital, Providence, Rhode Island, USA
| | - Caterina Iorio
- Department of Medical Biophysics, Campbell Family Cancer Research Institute, Ontario Cancer Institute, Princess Margaret Hospital, University Health Network, University of Toronto, Toronto, Ontario, Canada
| | - Kevin Yan
- Department of Orthopaedics, Brown University Alpert Medical School, Rhode Island Hospital, Providence, Rhode Island, USA
| | - Howard Yang
- College of Engineering, University of Rhode Island, Kingston, Rhode Island, USA
| | - Sunao Takeshita
- Department of Bone and Joint Disease, National Center for Geriatrics and Gerontology, Aichi, Japan
| | - Sumin Kang
- Department of Hematology and Oncology, Winship Cancer Institute, Emory University School of Medicine, Atlanta, Georgia, USA
| | - Benjamin G. Neel
- Department of Medical Biophysics, Campbell Family Cancer Research Institute, Ontario Cancer Institute, Princess Margaret Hospital, University Health Network, University of Toronto, Toronto, Ontario, Canada
- Laura and Isaac Perlmutter Cancer Center, NYU Langone Medical Center, New York University, New York, New York, USA
| | - Wentian Yang
- Department of Orthopaedics, Brown University Alpert Medical School, Rhode Island Hospital, Providence, Rhode Island, USA
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Benfato ID, Moretto TL, de Carvalho FP, Barthichoto M, Ferreira SM, Costa Júnior JM, Lazzarin MC, de Oliveira F, Martinez C, Prado de França Carvalho C, de Oliveira CAM. Spontaneous physical activity and mediators of energy homeostasis in the hypothalamus of mice from 4 to 10 months of age. Exp Physiol 2017; 102:1524-1534. [PMID: 28786537 DOI: 10.1113/ep086265] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2017] [Accepted: 08/04/2017] [Indexed: 11/08/2022]
Abstract
NEW FINDINGS What is the central question of this study? Is the initial decline of spontaneous physical activity (SPA) in mice related to impaired insulin and leptin signalling or brain-derived neurotrophic factor expression in the hypothalamus? What is the main finding and its importance? We showed that SPA started to decline at an early stage, concomitantly with an impairment of hypothalamic leptin signalling. Consequently, energy expenditure decreased and glucose tolerance worsened. Our results demonstrate the need to counteract the initial decline in SPA to avoid metabolic impairments and indicate the possible involvement of central leptin in the reduction in SPA with age. The biological control of physical activity is poorly understood. Age decreases insulin, leptin and brain-derived neurotrophic factor (BDNF) signalling in the hypothalamus, and all have been shown to modulate spontaneous physical activity (SPA). We investigated the age at which SPA starts to decline and whether this is associated with the emergence of hypothalamic insulin and leptin resistance and reduced BDNF expression. Spontaneous physical activity (and other parameters of locomotion) and energy expenditure were determined monthly in mice from the 4th to the 10th month of age. Metabolic and hypothalamic analyses were performed in 4-, 6- and 10-month-old mice. Spontaneous physical activity, distance travelled and speed of locomotion started to decrease in 6-month-old mice. The reduction in SPA became more evident from 8 months of age. Energy expenditure decreased from the 8th month. Hypothalamic BDNF protein expression and insulin signalling did not change throughout the time span studied. Leptin signalling decreased at 6 and 10 months compared with 4 months. Also, compared with 4 months, 6- and 10-month-old mice were glucose intolerant. In conclusion, SPA begins to decline in parallel with reduced hypothalamic leptin signalling. Metabolic impairment also manifests as SPA decreases, highlighting the need to understand the regulation of SPA in order to combat its decline.
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Affiliation(s)
- Izabelle Dias Benfato
- Department of Biosciences, Institute of Health and Society, Federal University of Sao Paulo, Santos, SP, Brazil
| | - Thaís Ludmilla Moretto
- Department of Biosciences, Institute of Health and Society, Federal University of Sao Paulo, Santos, SP, Brazil
| | | | - Marcela Barthichoto
- Department of Biosciences, Institute of Health and Society, Federal University of Sao Paulo, Santos, SP, Brazil
| | - Sandra Mara Ferreira
- Department of Structural and Functional Biology, Biology Institute, State University of Campinas (Unicamp), Campinas, SP, Brazil
| | - José Maria Costa Júnior
- Department of Structural and Functional Biology, Biology Institute, State University of Campinas (Unicamp), Campinas, SP, Brazil
| | - Mariana Cruz Lazzarin
- Department of Biosciences, Institute of Health and Society, Federal University of Sao Paulo, Santos, SP, Brazil
| | - Flávia de Oliveira
- Department of Biosciences, Institute of Health and Society, Federal University of Sao Paulo, Santos, SP, Brazil
| | - Carolina Martinez
- Department of Biosciences, Institute of Health and Society, Federal University of Sao Paulo, Santos, SP, Brazil
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Cellular Dynamics Controlled by Phosphatases. J Indian Inst Sci 2017. [DOI: 10.1007/s41745-016-0016-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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SHP2 sails from physiology to pathology. Eur J Med Genet 2015; 58:509-25. [PMID: 26341048 DOI: 10.1016/j.ejmg.2015.08.005] [Citation(s) in RCA: 158] [Impact Index Per Article: 17.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2015] [Revised: 07/24/2015] [Accepted: 08/30/2015] [Indexed: 02/08/2023]
Abstract
Over the two past decades, mutations of the PTPN11 gene, encoding the ubiquitous protein tyrosine phosphatase SHP2 (SH2 domain-containing tyrosine phosphatase 2), have been identified as the causal factor of several developmental diseases (Noonan syndrome (NS), Noonan syndrome with multiple lentigines (NS-ML), and metachondromatosis), and malignancies (juvenile myelomonocytic leukemia). SHP2 plays essential physiological functions in organism development and homeostasis maintenance by regulating fundamental intracellular signaling pathways in response to a wide range of growth factors and hormones, notably the pleiotropic Ras/Mitogen-Activated Protein Kinase (MAPK) and the Phosphoinositide-3 Kinase (PI3K)/AKT cascades. Analysis of the biochemical impacts of PTPN11 mutations first identified both loss-of-function and gain-of-function mutations, as well as more subtle defects, highlighting the major pathophysiological consequences of SHP2 dysregulation. Then, functional genetic studies provided insights into the molecular dysregulations that link SHP2 mutants to the development of specific traits of the diseases, paving the way for the design of specific therapies for affected patients. In this review, we first provide an overview of SHP2's structure and regulation, then describe its molecular roles, notably its functions in modulating the Ras/MAPK and PI3K/AKT signaling pathways, and its physiological roles in organism development and homeostasis. In the second part, we describe the different PTPN11 mutation-associated pathologies and their clinical manifestations, with particular focus on the biochemical and signaling outcomes of NS and NS-ML-associated mutations, and on the recent advances regarding the pathophysiology of these diseases.
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Tajan M, Batut A, Cadoudal T, Deleruyelle S, Le Gonidec S, Saint Laurent C, Vomscheid M, Wanecq E, Tréguer K, De Rocca Serra-Nédélec A, Vinel C, Marques MA, Pozzo J, Kunduzova O, Salles JP, Tauber M, Raynal P, Cavé H, Edouard T, Valet P, Yart A. LEOPARD syndrome-associated SHP2 mutation confers leanness and protection from diet-induced obesity. Proc Natl Acad Sci U S A 2014; 111:E4494-503. [PMID: 25288766 PMCID: PMC4210352 DOI: 10.1073/pnas.1406107111] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
LEOPARD syndrome (multiple Lentigines, Electrocardiographic conduction abnormalities, Ocular hypertelorism, Pulmonary stenosis, Abnormal genitalia, Retardation of growth, sensorineural Deafness; LS), also called Noonan syndrome with multiple lentigines (NSML), is a rare autosomal dominant disorder associating various developmental defects, notably cardiopathies, dysmorphism, and short stature. It is mainly caused by mutations of the PTPN11 gene that catalytically inactivate the tyrosine phosphatase SHP2 (Src-homology 2 domain-containing phosphatase 2). Besides its pleiotropic roles during development, SHP2 plays key functions in energetic metabolism regulation. However, the metabolic outcomes of LS mutations have never been examined. Therefore, we performed an extensive metabolic exploration of an original LS mouse model, expressing the T468M mutation of SHP2, frequently borne by LS patients. Our results reveal that, besides expected symptoms, LS animals display a strong reduction of adiposity and resistance to diet-induced obesity, associated with overall better metabolic profile. We provide evidence that LS mutant expression impairs adipogenesis, triggers energy expenditure, and enhances insulin signaling, three features that can contribute to the lean phenotype of LS mice. Interestingly, chronic treatment of LS mice with low doses of MEK inhibitor, but not rapamycin, resulted in weight and adiposity gains. Importantly, preliminary data in a French cohort of LS patients suggests that most of them have lower-than-average body mass index, associated, for tested patients, with reduced adiposity. Altogether, these findings unravel previously unidentified characteristics for LS, which could represent a metabolic benefit for patients, but may also participate to the development or worsening of some traits of the disease. Beyond LS, they also highlight a protective role of SHP2 global LS-mimicking modulation toward the development of obesity and associated disorders.
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Affiliation(s)
- Mylène Tajan
- Institut National de la Santé et de la Recherche Médicale, U1048, F-31432 Toulouse, France; Institut des Maladies Métaboliques et Cardiovasculaires, Université de Toulouse, Université Paul Sabatier, F-31432 Toulouse, France
| | - Aurélie Batut
- Institut National de la Santé et de la Recherche Médicale, U1048, F-31432 Toulouse, France; Institut des Maladies Métaboliques et Cardiovasculaires, Université de Toulouse, Université Paul Sabatier, F-31432 Toulouse, France
| | - Thomas Cadoudal
- Institut National de la Santé et de la Recherche Médicale, U1048, F-31432 Toulouse, France; Institut des Maladies Métaboliques et Cardiovasculaires, Université de Toulouse, Université Paul Sabatier, F-31432 Toulouse, France
| | - Simon Deleruyelle
- Institut National de la Santé et de la Recherche Médicale, U1048, F-31432 Toulouse, France; Institut des Maladies Métaboliques et Cardiovasculaires, Université de Toulouse, Université Paul Sabatier, F-31432 Toulouse, France
| | - Sophie Le Gonidec
- Institut National de la Santé et de la Recherche Médicale, U1048, F-31432 Toulouse, France; Institut des Maladies Métaboliques et Cardiovasculaires, Université de Toulouse, Université Paul Sabatier, F-31432 Toulouse, France
| | - Céline Saint Laurent
- Institut National de la Santé et de la Recherche Médicale, U1048, F-31432 Toulouse, France; Institut des Maladies Métaboliques et Cardiovasculaires, Université de Toulouse, Université Paul Sabatier, F-31432 Toulouse, France
| | - Maëlle Vomscheid
- Institut National de la Santé et de la Recherche Médicale, U1048, F-31432 Toulouse, France; Institut des Maladies Métaboliques et Cardiovasculaires, Université de Toulouse, Université Paul Sabatier, F-31432 Toulouse, France
| | - Estelle Wanecq
- Institut National de la Santé et de la Recherche Médicale, U1048, F-31432 Toulouse, France; Institut des Maladies Métaboliques et Cardiovasculaires, Université de Toulouse, Université Paul Sabatier, F-31432 Toulouse, France
| | - Karine Tréguer
- Institut National de la Santé et de la Recherche Médicale, U1048, F-31432 Toulouse, France; Institut des Maladies Métaboliques et Cardiovasculaires, Université de Toulouse, Université Paul Sabatier, F-31432 Toulouse, France
| | - Audrey De Rocca Serra-Nédélec
- Institut National de la Santé et de la Recherche Médicale, U1048, F-31432 Toulouse, France; Institut des Maladies Métaboliques et Cardiovasculaires, Université de Toulouse, Université Paul Sabatier, F-31432 Toulouse, France
| | - Claire Vinel
- Institut National de la Santé et de la Recherche Médicale, U1048, F-31432 Toulouse, France; Institut des Maladies Métaboliques et Cardiovasculaires, Université de Toulouse, Université Paul Sabatier, F-31432 Toulouse, France
| | - Marie-Adeline Marques
- Institut National de la Santé et de la Recherche Médicale, U1048, F-31432 Toulouse, France; Institut des Maladies Métaboliques et Cardiovasculaires, Université de Toulouse, Université Paul Sabatier, F-31432 Toulouse, France
| | - Joffrey Pozzo
- Cardiology Unit, University Hospital Center of Rangueil Toulouse, F-31432 Toulouse, France
| | - Oksana Kunduzova
- Institut National de la Santé et de la Recherche Médicale, U1048, F-31432 Toulouse, France; Institut des Maladies Métaboliques et Cardiovasculaires, Université de Toulouse, Université Paul Sabatier, F-31432 Toulouse, France
| | - Jean-Pierre Salles
- Endocrine, Bone Diseases, and Genetics Unit, Children's Hospital, University Hospital Center of Purpan Toulouse, F-31024 Toulouse, France
| | - Maithé Tauber
- Endocrine, Bone Diseases, and Genetics Unit, Children's Hospital, University Hospital Center of Purpan Toulouse, F-31024 Toulouse, France
| | - Patrick Raynal
- EA4568 Laboratoire Mécanismes des Cardiopathies et Résistances Hormonales dans le Syndrome de Noonan et les Syndromes Apparentés, Université de Toulouse, Université Paul Sabatier, F-31062 Toulouse, France; and
| | - Hélène Cavé
- Institut National de la Santé et de la Recherche Médicale Unité Mixte de Recherche S1131, Unité de Formation et de Recherche de Médecine Paris-Diderot-Institut Universitaire d'Hématologie Département de Génétique, Unité Fonctionnelle de Génétique Moléculaire Hôpital Robert Debré, F-75019 Paris, France
| | - Thomas Edouard
- Endocrine, Bone Diseases, and Genetics Unit, Children's Hospital, University Hospital Center of Purpan Toulouse, F-31024 Toulouse, France
| | - Philippe Valet
- Institut National de la Santé et de la Recherche Médicale, U1048, F-31432 Toulouse, France; Institut des Maladies Métaboliques et Cardiovasculaires, Université de Toulouse, Université Paul Sabatier, F-31432 Toulouse, France
| | - Armelle Yart
- Institut National de la Santé et de la Recherche Médicale, U1048, F-31432 Toulouse, France; Institut des Maladies Métaboliques et Cardiovasculaires, Université de Toulouse, Université Paul Sabatier, F-31432 Toulouse, France;
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9
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Role of different aberrant cell signalling pathways prevalent in acute lymphoblastic leukemia. Biologia (Bratisl) 2014. [DOI: 10.2478/s11756-014-0428-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
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10
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Xu E, Schwab M, Marette A. Role of protein tyrosine phosphatases in the modulation of insulin signaling and their implication in the pathogenesis of obesity-linked insulin resistance. Rev Endocr Metab Disord 2014; 15:79-97. [PMID: 24264858 DOI: 10.1007/s11154-013-9282-4] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Insulin resistance is a major disorder that links obesity to type 2 diabetes mellitus (T2D). It involves defects in the insulin actions owing to a reduced ability of insulin to trigger key signaling pathways in major metabolic tissues. The pathogenesis of insulin resistance involves several inhibitory molecules that interfere with the tyrosine phosphorylation of the insulin receptor and its downstream effectors. Among those, growing interest has been developed toward the protein tyrosine phosphatases (PTPs), a large family of enzymes that can inactivate crucial signaling effectors in the insulin signaling cascade by dephosphorylating their tyrosine residues. Herein we briefly review the role of several PTPs that have been shown to be implicated in the regulation of insulin action, and then focus on the Src homology 2 (SH2) domain-containing SHP1 and SHP2 enzymes, since recent reports have indicated major roles for these PTPs in the control of insulin action and glucose metabolism. Finally, the therapeutic potential of targeting PTPs for combating insulin resistance and alleviating T2D will be discussed.
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Affiliation(s)
- Elaine Xu
- Department of Medicine, Cardiology Axis of the Institut Universitaire de Cardiologie et de Pneumologie de Québec (Hôpital Laval), Ste-Foy, Québec, Canada, G1V 4G2
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11
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Lapinski PE, Meyer MF, Feng GS, Kamiya N, King PD. Deletion of SHP-2 in mesenchymal stem cells causes growth retardation, limb and chest deformity, and calvarial defects in mice. Dis Model Mech 2013; 6:1448-58. [PMID: 24077964 PMCID: PMC3820267 DOI: 10.1242/dmm.012849] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2013] [Accepted: 09/23/2013] [Indexed: 12/11/2022] Open
Abstract
In mice, induced global disruption of the Ptpn11 gene, which encodes the SHP-2 tyrosine phosphatase, results in severe skeletal abnormalities. To understand the extent to which skeletal abnormalities can be attributed to perturbation of SHP-2 function in bone-forming osteoblasts and chondrocytes, we generated mice in which disruption of Ptpn11 is restricted to mesenchymal stem cells (MSCs) and their progeny, which include both cell types. MSC-lineage-specific SHP-2 knockout (MSC SHP-2 KO) mice exhibited postnatal growth retardation, limb and chest deformity, and calvarial defects. These skeletal abnormalities were associated with an absence of mature osteoblasts and massive chondrodysplasia with a vast increase in the number of terminally differentiated hypertrophic chondrocytes in affected bones. Activation of mitogen activated protein kinases (MAPKs) and protein kinase B (PKB; also known as AKT) was impaired in bone-forming cells of MSC SHP-2 KO mice, which provides an explanation for the skeletal defects that developed. These findings reveal a cell-autonomous role for SHP-2 in bone-forming cells in mice in the regulation of skeletal development. The results add to our understanding of the pathophysiology of skeletal abnormalities observed in humans with germline mutations in the PTPN11 gene (e.g. Noonan syndrome and LEOPARD syndrome).
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Affiliation(s)
- Philip E. Lapinski
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - Melissa F. Meyer
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - Gen-Sheng Feng
- Department of Pathology, University of California San Diego, San Diego, CA 92093, USA
| | - Nobuhiro Kamiya
- Center for Excellence in Hip Disorders, Texas Scottish Rite Hospital for Children, Dallas, TX 75219, USA
| | - Philip D. King
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, MI 48109, USA
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12
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Senis YA. Protein-tyrosine phosphatases: a new frontier in platelet signal transduction. J Thromb Haemost 2013; 11:1800-13. [PMID: 24015866 DOI: 10.1111/jth.12359] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2013] [Indexed: 08/31/2023]
Abstract
Platelet activation must be tightly controlled in order to allow platelets to respond rapidly to vascular injury and prevent thrombosis from occurring. Protein-tyrosine phosphorylation is one of the main ways in which activation signals are transmitted in platelets. Although much is known about the protein-tyrosine kinases (PTKs) that initiate and propagate activation signals, relatively little is known about the protein-tyrosine phosphatases (PTPs) that modulate these signals in platelets. PTPs are a family of enzymes that dephosphorylate tyrosine residues in proteins and regulate signals transmitted within cells. PTPs have been implicated in a variety of pathological conditions, including cancer, diabetes and autoimmunity, but their functions in hemostasis and thrombosis remain largely undefined. Exciting new findings from a number of groups have revealed that PTPs are in fact critical regulators of platelet activation and thrombosis. The primary aim of this review is to highlight the unique and important functions of PTPs in regulating platelet activity. Establishing the functions of PTPs in platelets is essential to better understand the molecular basis of thrombosis and may lead to the development of improved antithrombotic therapies.
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Affiliation(s)
- Y A Senis
- Centre for Cardiovascular and Respiratory Sciences, Institute of Biomedical Research, School of Clinical and Experimental Medicine, College of Medical and Dental Sciences, University of Birmingham, Edgbaston, Birmingham, UK
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13
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Megakaryocyte-specific deletion of the protein-tyrosine phosphatases Shp1 and Shp2 causes abnormal megakaryocyte development, platelet production, and function. Blood 2013; 121:4205-20. [PMID: 23509158 DOI: 10.1182/blood-2012-08-449272] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The SH2 domain-containing protein-tyrosine phosphatases Shp1 and Shp2 have been implicated in regulating signaling from a variety of platelet and megakaryocyte receptors. In this study, we investigate the functions of Shp1 and Shp2 in megakaryocytes and platelets. Megakaryocyte/platelet (MP)-specific deletion of Shp1 in mice resulted in platelets being less responsive to collagen-related peptide due to reduced GPVI expression and signaling via the Src family kinase (SFK)-Syk-PLCγ2 pathway, and fibrinogen due to reduced SFK activity. By contrast, deletion of Shp2 in the MP lineage resulted in macrothrombocytopenia and platelets being hyper-responsive to anti-CLEC-2 antibody and fibrinogen. Shp1- and Shp2-deficient megakaryocytes had partial blocks at 2N/4N ploidy; however, only the latter exhibited reduced proplatelet formation, thrombopoietin, and integrin signaling. Mice deficient in both Shp1 and Shp2 were severely macrothrombocytopenic and had reduced platelet surface glycoprotein expression, including GPVI, αIIbβ3, and GPIbα. Megakaryocytes from these mice were blocked at 2N/4N ploidy and did not survive ex vivo. Deletion of the immunoreceptor tyrosine-based inhibition motif-containing receptor G6b-B in the MP lineage phenocopied multiple features of Shp1/2-deficient mice, suggesting G6b-B is a critical regulator of Shp1 and Shp2. This study establishes Shp1 and Shp2 as major regulators of megakaryocyte development, platelet production, and function.
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14
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Martinez CS, Piazza VG, Ratner LD, Matos MN, González L, Rulli SB, Miquet JG, Sotelo AI. Growth hormone STAT5-mediated signaling and its modulation in mice liver during the growth period. Growth Horm IGF Res 2013; 23:19-28. [PMID: 23245546 DOI: 10.1016/j.ghir.2012.11.002] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/06/2012] [Revised: 11/15/2012] [Accepted: 11/19/2012] [Indexed: 12/31/2022]
Abstract
Postnatal growth exhibits two instances of rapid growth in mice: the first is perinatal and independent of growth hormone (GH), the second is peripuberal and GH-dependent. Signal transducer and activator of transcription 5b (STAT5b) is the main GH-signaling mediator and it is related to IGF1 synthesis and somatic growth. The aim of this work was to assess differential STAT5 sensitivity to GH during the growth period in mouse liver of both sexes. Three representative ages were selected: 1-week-old animals, in the GH-independent phase of growth; 2.5-week-old mice, at the onset of the GH-dependent phase of growth; and 9-week-old young adults. GH-signaling mediators were assessed by immunoblotting, quantitative RT-PCR and immunohistochemistry. GH-induced STAT5 phosphorylation is low at one-week and maximal at 2.5-weeks of age when compared to young adults, accompanied by higher protein content at the onset of growth. Suppressor CIS and phosphatase PTP1B exhibit high levels in one-week animals, which gradually decline, while SOCS2 and SOCS3 display higher levels at adulthood. Nuclear phosphorylated STAT5 is low in one-week animals while in 2.5-week animals it is similar to 9-week control; expression of SOCS3, an early response GH-target gene, mimics this pattern. STAT5 coactivators glucocorticoid receptor (GR) and hepatic nuclear factor 1 (HNF1) abundance is higher in adulthood. Therefore, GH-induced STAT5 signaling presents age-dependent activity in liver, with its maximum coinciding with the onset of GH-dependent phase of growth, accompanied by an age-dependent variation of modulating factors. This work contributes to elucidate the molecular mechanisms implicated in GH responsiveness during growth.
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Affiliation(s)
- Carolina S Martinez
- Instituto de Química y Fisicoquímica Biológicas (UBA-CONICET), Universidad de Buenos Aires, Facultad de Farmacia y Bioquímica, Junín 956, 1113, Buenos Aires, Argentina
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15
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Nagata N, Matsuo K, Bettaieb A, Bakke J, Matsuo I, Graham J, Xi Y, Liu S, Tomilov A, Tomilova N, Gray S, Jung DY, Ramsey JJ, Kim JK, Cortopassi G, Havel PJ, Haj FG. Hepatic Src homology phosphatase 2 regulates energy balance in mice. Endocrinology 2012; 153:3158-69. [PMID: 22619361 PMCID: PMC3380313 DOI: 10.1210/en.2012-1406] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The Src homology 2 domain-containing protein-tyrosine phosphatase Src homology phosphatase 2 (Shp2) is a negative regulator of hepatic insulin action in mice fed regular chow. To investigate the role of hepatic Shp2 in lipid metabolism and energy balance, we determined the metabolic effects of its deletion in mice challenged with a high-fat diet (HFD). We analyzed body mass, lipid metabolism, insulin sensitivity, and glucose tolerance in liver-specific Shp2-deficient mice (referred to herein as LSHKO) and control mice fed HFD. Hepatic Shp2 protein expression is regulated by nutritional status, increasing in mice fed HFD and decreasing during fasting. LSHKO mice gained less weight and exhibited increased energy expenditure compared with control mice. In addition, hepatic Shp2 deficiency led to decreased liver steatosis, enhanced insulin-induced suppression of hepatic glucose production, and impeded the development of insulin resistance after high-fat feeding. At the molecular level, LSHKO exhibited decreased hepatic endoplasmic reticulum stress and inflammation compared with control mice. In addition, tyrosine and serine phosphorylation of total and mitochondrial signal transducer and activator of transcription 3 were enhanced in LSHKO compared with control mice. In line with this observation and the increased energy expenditure of LSHKO, oxygen consumption rate was higher in liver mitochondria of LSHKO compared with controls. Collectively, these studies identify hepatic Shp2 as a novel regulator of systemic energy balance under conditions of high-fat feeding.
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Affiliation(s)
- Naoto Nagata
- Department of Nutrition, University of California Davis, Davis, California 95616, USA
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16
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Sharma N, Kumar V, Everingham S, Mali RS, Kapur R, Zeng LF, Zhang ZY, Feng GS, Hartmann K, Roers A, Craig AWB. SH2 domain-containing phosphatase 2 is a critical regulator of connective tissue mast cell survival and homeostasis in mice. Mol Cell Biol 2012; 32:2653-63. [PMID: 22566685 PMCID: PMC3416204 DOI: 10.1128/mcb.00308-12] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2012] [Accepted: 04/28/2012] [Indexed: 12/28/2022] Open
Abstract
Mast cells require KIT receptor tyrosine kinase signaling for development and survival. Here, we report that SH2 domain-containing phosphatase 2 (SHP2) signaling downstream of KIT is essential for mast cell survival and homeostasis in mice. Using a novel mouse model with shp2 deletion within mature mast cells (MC-shp2 knockout [KO]), we find that SHP2 is required for the homeostasis of connective tissue mast cells. Consistently with the loss of skin mast cells, MC-shp2 KO mice fail to mount a passive late-phase cutaneous anaphylaxis response. To better define the phenotype of shp2-deficient mast cells, we used an inducible shp2 knockout approach in bone marrow-derived mast cells (BMMCs) or cultured peritoneal mast cells and found that SHP2 promotes mast cell survival. We show that SHP2 promotes KIT signaling to extracellular signal-regulated kinase (ERK) mitogen-activated protein kinase and downregulation of the proapoptotic protein Bim in BMMCs. Also, SHP2-deficient BMMCs failed to repopulate mast cells in mast cell-deficient mice. Silencing of Bim partially rescued survival defects in shp2-deficient BMMCs, consistent with the importance of a KIT → SHP2 → Ras/ERK pathway in suppressing Bim and promoting mast cell survival. Thus, SHP2 is a key node in a mast cell survival pathway and a new potential therapeutic target in diseases involving mast cells.
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Affiliation(s)
- Namit Sharma
- Department of Biomedical and Molecular Sciences, Division of Cancer Biology & Genetics, Queen's University, Kingston, Ontario, Canada
| | - Vijay Kumar
- Department of Biomedical and Molecular Sciences, Division of Cancer Biology & Genetics, Queen's University, Kingston, Ontario, Canada
| | - Stephanie Everingham
- Department of Biomedical and Molecular Sciences, Division of Cancer Biology & Genetics, Queen's University, Kingston, Ontario, Canada
| | - Raghuveer Singh Mali
- Department of Pediatrics, Herman B. Wells Center for Pediatric Research, Indianapolis, Indiana, USA
| | - Reuben Kapur
- Department of Pediatrics, Herman B. Wells Center for Pediatric Research, Indianapolis, Indiana, USA
| | - Li-Fan Zeng
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Bloomington, Indiana, USA
| | - Zhong-Yin Zhang
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Bloomington, Indiana, USA
| | - Gen-Sheng Feng
- Department of Pathology, University of California, San Diego, La Jolla, California, USA
| | - Karin Hartmann
- Department of Dermatology, University of Cologne, Cologne, Germany
| | - Axel Roers
- Institute for Immunology, Technical University of Dresden, Dresden, Germany
| | - Andrew W. B. Craig
- Department of Biomedical and Molecular Sciences, Division of Cancer Biology & Genetics, Queen's University, Kingston, Ontario, Canada
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17
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Schramm C, Fine DM, Edwards MA, Reeb AN, Krenz M. The PTPN11 loss-of-function mutation Q510E-Shp2 causes hypertrophic cardiomyopathy by dysregulating mTOR signaling. Am J Physiol Heart Circ Physiol 2011; 302:H231-43. [PMID: 22058153 DOI: 10.1152/ajpheart.00665.2011] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The identification of mutations in PTPN11 (encoding the protein tyrosine phosphatase Shp2) in families with congenital heart disease has facilitated mechanistic studies of various cardiovascular defects. However, the roles of normal and mutant Shp2 in the developing heart are still poorly understood. Furthermore, it remains unclear how Shp2 loss-of-function (LOF) mutations cause LEOPARD Syndrome (also termed Noonan Syndrome with multiple lentigines), which is characterized by congenital heart defects such as pulmonary valve stenosis and hypertrophic cardiomyopathy (HCM). In normal hearts, Shp2 controls cardiomyocyte size by regulating signaling through protein kinase B (Akt) and mammalian target of rapamycin (mTOR). We hypothesized that Shp2 LOF mutations dysregulate this pathway, resulting in HCM. For our studies, we chose the Shp2 mutation Q510E, a dominant-negative LOF mutation associated with severe early onset HCM. Newborn mice with cardiomyocyte-specific overexpression of Q510E-Shp2 starting before birth displayed increased cardiomyocyte sizes, heart-to-body weight ratios, interventricular septum thickness, and cardiomyocyte disarray. In 3-mo-old hearts, interstitial fibrosis was detected. Echocardiographically, ventricular walls were thickened and contractile function was depressed. In ventricular tissue samples, signaling through Akt/mTOR was hyperactivated, indicating that the presence of Q510E-Shp2 led to upregulation of this pathway. Importantly, rapamycin treatment started shortly after birth rescued the Q510E-Shp2-induced phenotype in vivo. If rapamycin was started at 6 wk of age, HCM was also ameliorated. We also generated a second mouse model in which cardiomyocyte-specific Q510E-Shp2 overexpression started after birth. In contrast to the first model, these mice did not develop HCM. In summary, our studies establish a role for mTOR signaling in HCM caused by Q510E-Shp2. Q510E-Shp2 overexpression in the cardiomyocyte population alone was sufficient to induce the phenotype. Furthermore, the pathomechanism was triggered pre- but not postnatally. However, postnatal rapamycin treatment could still reverse already established HCM, which may have important therapeutic implications.
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Affiliation(s)
- Christine Schramm
- Department of Medical Pharmacology & Physiology, University of Missouri-Columbia, 65211, USA
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18
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Cooke M, Orlando U, Maloberti P, Podestá EJ, Cornejo Maciel F. Tyrosine phosphatase SHP2 regulates the expression of acyl-CoA synthetase ACSL4. J Lipid Res 2011; 52:1936-48. [PMID: 21903867 DOI: 10.1194/jlr.m015552] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Acyl-CoA synthetase 4 (ACSL4) is implicated in fatty acid metabolism with marked preference for arachidonic acid (AA). ACSL4 plays crucial roles in physiological functions such as steroid synthesis and in pathological processes such as tumorigenesis. However, factors regulating ACSL4 mRNA and/or protein levels are not fully described. Because ACSL4 protein expression requires tyrosine phosphatase activity, in this study we aimed to identify the tyrosine phosphatase involved in ACSL4 expression. NSC87877, a specific inhibitor of the tyrosine phosphatase SHP2, reduced ACSL4 protein levels in ACSL4-rich breast cancer cells and steroidogenic cells. Indeed, overexpression of an active form of SHP2 increased ACSL4 protein levels in MA-10 Leydig steroidogenic cells. SHP2 has to be activated through a cAMP-dependent pathway to exert its effect on ACSL4. The effects could be specifically attributed to SHP2 because knockdown of the phosphatase reduced ACSL4 mRNA and protein levels. Through the action on ACSL4 protein levels, SHP2 affected AA-CoA production and metabolism and, finally, the steroidogenic capacity of MA-10 cells: overexpression (or knockdown) of SHP2 led to increased (or decreased) steroid production. We describe for the first time the involvement of SHP2 activity in the regulation of the expression of the fatty acid-metabolizing enzyme ACSL4.
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Affiliation(s)
- Mariana Cooke
- Department of Biochemistry, School of Medicine, University of Buenos Aires, Buenos Aires, Argentina
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19
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Bettaieb A, Matsuo K, Matsuo I, Nagata N, Chahed S, Liu S, Haj FG. Adipose-specific deletion of Src homology phosphatase 2 does not significantly alter systemic glucose homeostasis. Metabolism 2011; 60:1193-201. [PMID: 21353259 PMCID: PMC4433310 DOI: 10.1016/j.metabol.2011.01.004] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/12/2010] [Revised: 12/21/2010] [Accepted: 01/12/2011] [Indexed: 10/18/2022]
Abstract
The SH2 domain-containing protein-tyrosine phosphatase Src homology phosphatase 2 (Shp2) has been implicated in a variety of growth factor signaling pathways, but its metabolic role in some peripheral insulin-responsive tissues remains unknown. To address the metabolic function of Shp2 in adipose tissue, we generated mice with adipose-specific Shp2 deletion using adiponectin-Cre transgenic mice. We then analyzed insulin sensitivity, glucose tolerance, and body mass in adipose-specific Shp2-deficient and control mice on regular chow and high-fat diet (HFD). Control mice on HFD exhibited increased Shp2 expression in various adipose depots compared with those on regular chow. Adiponectin-Cre mice enabled efficient and specific deletion of Shp2 in adipose tissue. However, adipose Shp2 deletion did not significantly alter body mass in mice on chow or HFD. In addition, mice with adipose Shp2 deletion exhibited comparable insulin sensitivity and glucose tolerance compared with controls. Consistent with this, basal and insulin-stimulated Erk and Akt phosphorylations were comparable in adipose tissue of Shp2-deficient and control mice. Our findings indicate that adipose-specific Shp2 deletion does not significantly alter systemic insulin sensitivity and glucose homeostasis.
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Affiliation(s)
- Ahmed Bettaieb
- University of California Davis, Nutrition Department, Davis, CA 95616
| | - Kosuke Matsuo
- University of California Davis, Nutrition Department, Davis, CA 95616
| | - Izumi Matsuo
- University of California Davis, Nutrition Department, Davis, CA 95616
| | - Naoto Nagata
- University of California Davis, Nutrition Department, Davis, CA 95616
| | - Samah Chahed
- University of California Davis, Nutrition Department, Davis, CA 95616
| | - Siming Liu
- University of California Davis, Nutrition Department, Davis, CA 95616
| | - Fawaz G. Haj
- University of California Davis, Nutrition Department, Davis, CA 95616
- Corresponding author: University of California Davis, 3135 Meyer Hall, Davis, CA 95616, Fax: (530) 753-8966, Tel: (530) 752-3214,
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20
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Essential role for Ptpn11 in survival of hematopoietic stem and progenitor cells. Blood 2011; 117:4253-61. [PMID: 21398220 DOI: 10.1182/blood-2010-11-319517] [Citation(s) in RCA: 75] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Src homology 2 domain-containing phosphatase 2 (Shp2), encoded by Ptpn11, is a member of the nonreceptor protein-tyrosine phosphatase family, and functions in cell survival, proliferation, migration, and differentiation in many tissues. Here we report that loss of Ptpn11 in murine hematopoietic cells leads to bone marrow aplasia and lethality. Mutant mice show rapid loss of hematopoietic stem cells (HSCs) and immature progenitors of all hematopoietic lineages in a gene dosage-dependent and cell-autonomous manner. Ptpn11-deficient HSCs and progenitors undergo apoptosis concomitant with increased Noxa expression. Mutant HSCs/progenitors also show defective Erk and Akt activation in response to stem cell factor and diminished thrombopoietin-evoked Erk activation. Activated Kras alleviates the Ptpn11 requirement for colony formation by progenitors and cytokine/growth factor responsiveness of HSCs, indicating that Ras is functionally downstream of Shp2 in these cells. Thus, Shp2 plays a critical role in controlling the survival and maintenance of HSCs and immature progenitors in vivo.
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Matsuo K, Delibegovic M, Matsuo I, Nagata N, Liu S, Bettaieb A, Xi Y, Araki K, Yang W, Kahn BB, Neel BG, Haj FG. Altered glucose homeostasis in mice with liver-specific deletion of Src homology phosphatase 2. J Biol Chem 2010; 285:39750-8. [PMID: 20841350 DOI: 10.1074/jbc.m110.153734] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The Src homology 2 domain-containing protein-tyrosine phosphatase Shp2 has been implicated in a variety of growth factor signaling pathways, but its role in insulin signaling has remained unresolved. In vitro studies suggest that Shp2 is both a negative and positive regulator of insulin signaling, although its physiological function in a number of peripheral insulin-responsive tissues remains unknown. To address the metabolic role of Shp2 in the liver, we generated mice with either chronic or acute hepatic Shp2 deletion using tissue-specific Cre-LoxP and adenoviral Cre approaches, respectively. We then analyzed insulin sensitivity, glucose tolerance, and insulin signaling in liver-specific Shp2-deficient and control mice. Mice with chronic Shp2 deletion exhibited improved insulin sensitivity and increased glucose tolerance compared with controls. Acute Shp2 deletion yielded comparable results, indicating that the observed metabolic effects are directly caused by the lack of Shp2 in the liver. These findings correlated with, and were most likely caused by, direct dephosphorylation of insulin receptor substrate (IRS)1/2 in the liver, accompanied by increased PI3K/Akt signaling. In contrast, insulin-induced ERK activation was dramatically attenuated, yet there was no effect on the putative ERK site on IRS1 (Ser(612)) or on S6 kinase 1 activity. These studies show that Shp2 is a negative regulator of hepatic insulin action, and its deletion enhances the activation of PI3K/Akt pathway downstream of the insulin receptor.
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Affiliation(s)
- Kosuke Matsuo
- Department of Nutrition, University of California, Davis, California 95616, USA
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22
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Abstract
Deregulation of signaling pathways, through mutation or other molecular changes, can ultimately result in disease. The tyrosine phosphatase Shp2 has emerged as a major regulator of receptor tyrosine kinase (RTK) and cytokine receptor signaling. In the last decade, germline mutations in the human PTPN11 gene, encoding Shp2, were linked to Noonan (NS) and LEOPARD syndromes, two multisymptomatic developmental disorders that are characterized by short stature, craniofacial defects, cardiac defects, and mental retardation. Somatic Shp2 mutations are also associated with several types of human malignancies, such as the most common juvenile leukemia, juvenile myelomonocytic leukemia (JMML). Whereas NS and JMML are caused by gain-of-function (GOF) mutations of Shp2, loss-of-function (LOF) mutations are thought to be associated with LEOPARD syndrome. Animal models that carry conditional LOF and GOF mutations have allowed a better understanding of the mechanism of Shp2 function in disease, and shed light on the role of Shp2 in signaling pathways that control decisive events during embryonic development or during cellular transformation/tumorigenesis.
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23
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Aoki Y, Niihori T, Narumi Y, Kure S, Matsubara Y. The RAS/MAPK syndromes: novel roles of the RAS pathway in human genetic disorders. Hum Mutat 2008; 29:992-1006. [DOI: 10.1002/humu.20748] [Citation(s) in RCA: 274] [Impact Index Per Article: 17.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
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Xu D, Qu CK. Protein tyrosine phosphatases in the JAK/STAT pathway. FRONT BIOSCI-LANDMRK 2008; 13:4925-32. [PMID: 18508557 DOI: 10.2741/3051] [Citation(s) in RCA: 223] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The Janus kinase (JAK)/signal transducer and activator of transcription (STAT) pathway is crucial in controlling cellular activities in response to extracellular cytokines. Dysfunctions of the JAK/STAT pathway result in various hematopoietic and immune disorders. The central events in regulating this pathway are tyrosine phosphorylation and dephosphorylation of the signaling components, which are carried out by protein tyrosine kinases and protein tyrosine phosphatases (PTP), respectively. Here, we review recent advances in the regulatory roles of PTPs, in particular, SHP2 phosphatase, in the JAK/STAT signaling pathway.
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Affiliation(s)
- Dan Xu
- Department of Medicine, Division of Hematology/Oncology, Case Comprehensive Cancer Center, Case Western Reserve University, Cleveland, Ohio 44106, USA
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25
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Hendriks WJAJ, Elson A, Harroch S, Stoker AW. Protein tyrosine phosphatases: functional inferences from mouse models and human diseases. FEBS J 2008; 275:816-30. [DOI: 10.1111/j.1742-4658.2008.06249.x] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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26
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Writzl K, Hoovers J, Sistermans EA, Hennekam RCM. LEOPARD syndrome with partly normal skin and sex chromosome mosaicism. Am J Med Genet A 2008; 143A:2612-5. [PMID: 17935252 DOI: 10.1002/ajmg.a.31991] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
We report on a family with LEOPARD syndrome which was molecularly proven (p.Thr468Met in PTPN11) in a father and his adult son. The father had multiple lentigines dispersed equally over his body; the son was similarly affected except for the left part of thorax, back and left arm, which were completely devoid of lentigines and only showed a few nevi. In addition, the son was found to have a mosaic karyotype, 47,XYY/46,XY, in lymphocytes. Skin biopsies from the pigmented and unpigmented forearm showed that mainly a 47,XYY karyotype was present in the pigmented skin and mainly a 46,XY karyotype in the unpigmented skin. In both fibroblast cultures the PTPN11 mutation was present, and no additional mutation could be detected. We discuss the various possible explanations for this phenotype, which include the possibility of coincidence; revertant mosaicism; silencing of a second PTPN11 mutation; gene(s) located on a sex chromosome influencing the phenotype; and epigenetic influences. We favor that the co-occurrence of a sex chromosome mosaicism and mosaicism for skin symptoms in a single patient with LEOPARD syndrome is coincidence, but that mosaicism for LEOPARD skin symptoms in itself may well be more frequent and needs additional studies. Each of the above-hypothesized mechanisms may then remain possible.
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Affiliation(s)
- Karin Writzl
- Department of Clinical Genetics, Great Ormond Street Hospital for Children, UCL, London, UK
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27
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Abstract
Congenital heart defects occur in nearly 1% of human live births and many are lethal if not surgically repaired. In addition, the genetic contribution to congenital or acquired cardiovascular diseases that are silent at birth, but progress to cause significant disease in later life is being increasingly appreciated. Heart development and structure are highly conserved between mouse and human. The discoveries that are being made in this model system are highly relevant to understanding the pathogenesis of human heart defects whether they occus in isolation, or in the context of a syndrome. Many of the genes required for cardiovascular development were discovered fortuitously when early lethality or structural defects were observed in mouse mutants generated for other purposes, and relevant genes continue to be defined in this manner. Candidate genes for this process are being identified by their roles other species, or by their expression in pertinent tissues in mice. In this review, I will briefly summarize heart development as currently understood in the mouse, and then discuss how complementary studies in mouse and human have identified genes and pathways that are critical for normal cardiovascular development, and for maintaining the structure and function of this organ system throughout life.
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Affiliation(s)
- Anne Moon
- School of Medicine, University of Utah, Salt Lake City, UT 84112, USA
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28
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Koren S, Fantus IG. Inhibition of the protein tyrosine phosphatase PTP1B: potential therapy for obesity, insulin resistance and type-2 diabetes mellitus. Best Pract Res Clin Endocrinol Metab 2007; 21:621-40. [PMID: 18054739 DOI: 10.1016/j.beem.2007.08.004] [Citation(s) in RCA: 180] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The global epidemic of obesity and type-2 diabetes mellitus (T2DM) has highlighted the need for new therapeutic approaches. The association of insulin resistance with these disorders and the knowledge that insulin receptor signaling is mediated by tyrosine (Tyr) phosphorylation have generated great interest in the regulation of the balance between Tyr phosphorylation and dephosphorylation. Several protein Tyr phosphatases (PTPs) have been implicated in the regulation of insulin action, with the most convincing data for PTP1B. Murine models targeting PTP1B, PTP1B(-/-)mice, demonstrate enhanced insulin sensitivity without the weight gain seen with other insulin sensitizers such as peroxisome proliferator-activated receptor gamma (PPARgamma) agonists, probably due to a second action of PTP1B as a negative regulator of leptin signaling. Despite intensive efforts and recent progress, a safe, selective and efficacious PTP1B inhibitor has yet to be identified.
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Affiliation(s)
- Shlomit Koren
- Department of Medicine and The Banting and Best Diabetes Centre, Toronto General Research Institute, University Health Network, University of Toronto, Toronto, Ontario, Canada
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29
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Pilecka I, Patrignani C, Pescini R, Curchod ML, Perrin D, Xue Y, Yasenchak J, Clark A, Magnone MC, Zaratin P, Valenzuela D, Rommel C, van Huijsduijnen RH. Protein-tyrosine Phosphatase H1 Controls Growth Hormone Receptor Signaling and Systemic Growth. J Biol Chem 2007; 282:35405-15. [DOI: 10.1074/jbc.m705814200] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
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30
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Hoff H, Brunner-Weinzierl MC. The tyrosine phosphatase SHP-2 regulates differentiation and apoptosis of individual primary T lymphocytes. Eur J Immunol 2007; 37:1072-86. [PMID: 17330819 DOI: 10.1002/eji.200636240] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Although phosphatases are key players of intracellular processes, not much is known about the phosphatase SHP-2 during T cell differentiation. Here we show that ectopic over-expression of SHP-2 in primary T helper cells directly reduced the frequency of individual lymphocytes expressing pro-inflammatory cytokines after antigen-specific stimulation by a mechanism impairing activation of protein kinase C. In addition we demonstrate that SHP-2 mediates enhanced migration upon CXCR4 signaling in a G-protein-dependent manner. Most strikingly, SHP-2 mediated a dramatic increase in apoptosis by highly enhanced activation of caspases. Co-immunoprecipitations of SHP-2 and c-Cbl from primary T helper cells demonstrated that SHP-2 strongly interacts with the ubiquitin ligase c-Cbl, indicating that c-Cbl could mediate the negative signals of SHP-2. Our results show that SHP-2 signal transduction regulates central checkpoints of T cell differentiation by the activation of distinct signaling cascades.
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Affiliation(s)
- Holger Hoff
- Deutsches Rheuma-Forschungszentrum, Berlin, Germany
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31
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Abstract
Tyrosyl phosphorylation plays a critical role in multiple signaling pathways regulating innate and acquired immunity. Although tyrosyl phosphorylation is a reversible process, we know much more about the functions of protein-tyrosine kinases (PTKs) than about protein-tyrosine phosphatases (PTPs). Genome sequencing efforts have revealed a large and diverse superfamily of PTPs, which can be subdivided into receptor-like (RPTPs) and nonreceptor (NRPTPs). The role of the RPTP CD45 in immune cell signaling is well known, but those of most other PTPs remain poorly understood. Here, we review the mechanism of action, regulation, and physiological functions of NRPTPs in immune cell signaling. Such an analysis indicates that PTPs are as important as PTKs in regulating the immune system.
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Affiliation(s)
- Lily I Pao
- Cancer Biology Program, Division of Hematology-Oncology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts 02215, USA.
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32
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Kim SK, Novak RF. The role of intracellular signaling in insulin-mediated regulation of drug metabolizing enzyme gene and protein expression. Pharmacol Ther 2006; 113:88-120. [PMID: 17097148 PMCID: PMC1828071 DOI: 10.1016/j.pharmthera.2006.07.004] [Citation(s) in RCA: 113] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2006] [Accepted: 07/18/2006] [Indexed: 12/28/2022]
Abstract
Endogenous factors, including hormones, growth factors and cytokines, play an important role in the regulation of hepatic drug metabolizing enzyme expression in both physiological and pathophysiological conditions. Diabetes, fasting, obesity, protein-calorie malnutrition and long-term alcohol consumption produce changes in hepatic drug metabolizing enzyme gene and protein expression. This difference in expression alters the metabolism of xenobiotics, including procarcinogens, carcinogens, toxicants and therapeutic agents, potentially impacting the efficacy and safety of therapeutic agents, and/or resulting in drug-drug interactions. Although the mechanisms by which xenobiotics regulate drug metabolizing enzymes have been studied intensively, less is known regarding the cellular signaling pathways and components which regulate drug metabolizing enzyme gene and protein expression in response to hormones and cytokines. Recent findings, however, have revealed that several cellular signaling pathways are involved in hormone- and growth factor-mediated regulation of drug metabolizing enzymes. Our laboratory has reported that insulin and growth factors regulate drug metabolizing enzyme gene and protein expression, including cytochromes P450 (CYP), glutathione S-transferases (GST) and microsomal epoxide hydrolase (mEH), through receptors which are members of the large receptor tyrosine kinase (RTK) family, and by downstream effectors such as phosphatidylinositol 3-kinase, mitogen activated protein kinase (MAPK), Akt/protein kinase B (PKB), mammalian target of rapamycin (mTOR), and the p70 ribosomal protein S6 kinase (p70S6 kinase). Here, we review current knowledge of the signaling pathways implicated in regulation of drug metabolizing enzyme gene and protein expression in response to insulin and growth factors, with the goal of increasing our understanding of how disease affects these signaling pathways, components, and ultimately gene expression and translational control.
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Affiliation(s)
- Sang K. Kim
- Institute of Environmental Health Sciences, Wayne State University, 2727 Second Avenue, Room 4000, Detroit, MI 48201, USA
- College of Pharmacy and Research Center for Transgenic Cloned Pigs, Chungnam National University, Daejeon 305-764, South Korea
| | - Raymond F. Novak
- Institute of Environmental Health Sciences, Wayne State University, 2727 Second Avenue, Room 4000, Detroit, MI 48201, USA
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Liu BA, Jablonowski K, Raina M, Arcé M, Pawson T, Nash PD. The human and mouse complement of SH2 domain proteins-establishing the boundaries of phosphotyrosine signaling. Mol Cell 2006; 22:851-868. [PMID: 16793553 DOI: 10.1016/j.molcel.2006.06.001] [Citation(s) in RCA: 232] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2006] [Revised: 05/19/2006] [Accepted: 06/02/2006] [Indexed: 01/07/2023]
Abstract
SH2 domains are interaction modules uniquely dedicated to the recognition of phosphotyrosine sites and are embedded in proteins that couple protein-tyrosine kinases to intracellular signaling pathways. Here, we report a comprehensive bioinformatics, structural, and functional view of the human and mouse complement of SH2 domain proteins. This information delimits the set of SH2-containing effectors available for PTK signaling and will facilitate the systems-level analysis of pTyr-dependent protein-protein interactions and PTK-mediated signal transduction. The domain-based architecture of SH2-containing proteins is of more general relevance for understanding the large family of protein interaction domains and the modular organization of the majority of human proteins.
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Affiliation(s)
- Bernard A Liu
- Ben May Institute for Cancer Research and the Committee on Cancer Biology, The University of Chicago, Chicago, Illinois 60637
| | - Karl Jablonowski
- Ben May Institute for Cancer Research and the Committee on Cancer Biology, The University of Chicago, Chicago, Illinois 60637
| | - Monica Raina
- Samuel Lunenfeld Research Institute, Mount Sinai Hospital, Toronto M5G 1X5, Canada
| | - Michael Arcé
- Ben May Institute for Cancer Research and the Committee on Cancer Biology, The University of Chicago, Chicago, Illinois 60637
| | - Tony Pawson
- Samuel Lunenfeld Research Institute, Mount Sinai Hospital, Toronto M5G 1X5, Canada.
| | - Piers D Nash
- Ben May Institute for Cancer Research and the Committee on Cancer Biology, The University of Chicago, Chicago, Illinois 60637.
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34
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Yang W, Klaman LD, Chen B, Araki T, Harada H, Thomas SM, George EL, Neel BG. An Shp2/SFK/Ras/Erk signaling pathway controls trophoblast stem cell survival. Dev Cell 2006; 10:317-27. [PMID: 16516835 DOI: 10.1016/j.devcel.2006.01.002] [Citation(s) in RCA: 191] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2005] [Revised: 12/28/2005] [Accepted: 01/05/2006] [Indexed: 11/18/2022]
Abstract
Little is known about how growth factors control tissue stem cell survival and proliferation. We analyzed mice with a null mutation of Shp2 (Ptpn11), a key component of receptor tyrosine kinase signaling. Null embryos die peri-implantation, much earlier than mice that express an Shp2 truncation. Shp2 null blastocysts initially develop normally, but they subsequently exhibit inner cell mass death, diminished numbers of trophoblast giant cells, and failure to yield trophoblast stem (TS) cell lines. Molecular markers reveal that the trophoblast lineage, which requires fibroblast growth factor-4 (FGF4), is specified but fails to expand normally. Moreover, deletion of Shp2 in TS cells causes rapid apoptosis. We show that Shp2 is required for FGF4-evoked activation of the Src/Ras/Erk pathway that culminates in phosphorylation and destabilization of the proapoptotic protein Bim. Bim depletion substantially blocks apoptosis and significantly restores Shp2 null TS cell proliferation, thereby establishing a key mechanism by which FGF4 controls stem cell survival.
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Affiliation(s)
- Wentian Yang
- Cancer Biology Program, Division of Hematology/Oncology, Department of Medicine, Beth Israel Deaconess Medical Center, Boston, Massachusetts 02115, USA.
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35
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Tartaglia M, Martinelli S, Stella L, Bocchinfuso G, Flex E, Cordeddu V, Zampino G, Burgt IVD, Palleschi A, Petrucci TC, Sorcini M, Schoch C, Foa R, Emanuel PD, Gelb BD. Diversity and functional consequences of germline and somatic PTPN11 mutations in human disease. Am J Hum Genet 2006; 78:279-90. [PMID: 16358218 PMCID: PMC1380235 DOI: 10.1086/499925] [Citation(s) in RCA: 290] [Impact Index Per Article: 16.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2005] [Accepted: 11/17/2005] [Indexed: 12/17/2022] Open
Abstract
Germline mutations in PTPN11, the gene encoding the protein tyrosine phosphatase SHP-2, cause Noonan syndrome (NS) and the clinically related LEOPARD syndrome (LS), whereas somatic mutations in the same gene contribute to leukemogenesis. On the basis of our previously gathered genetic and biochemical data, we proposed a model that splits NS- and leukemia-associated PTPN11 mutations into two major classes of activating lesions with differential perturbing effects on development and hematopoiesis. To test this model, we investigated further the diversity of germline and somatic PTPN11 mutations, delineated the association of those mutations with disease, characterized biochemically a panel of mutant SHP-2 proteins recurring in NS, LS, and leukemia, and performed molecular dynamics simulations to determine the structural effects of selected mutations. Our results document a strict correlation between the identity of the lesion and disease and demonstrate that NS-causative mutations have less potency for promoting SHP-2 gain of function than do leukemia-associated ones. Furthermore, we show that the recurrent LS-causing Y279C and T468M amino acid substitutions engender loss of SHP-2 catalytic activity, identifying a previously unrecognized behavior for this class of missense PTPN11 mutations.
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Affiliation(s)
- Marco Tartaglia
- Dipartimento di Biologia Cellulare e Neuroscienze, Istituto Superiore di Sanita, Rome, Italy.
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36
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Evans JL, Jallal B. Protein tyrosine phosphatases: their role in insulin action and potential as drug targets. Expert Opin Investig Drugs 2005; 8:139-60. [PMID: 15992069 DOI: 10.1517/13543784.8.2.139] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Protein tyrosine phosphatases (PTPases) are the enzymes responsible for the selective dephosphorylation of tyrosine residues. PTPases function to regulate a wide array of biological responses mediated by growth factors and other stimuli by balancing the cellular level of phosphotyrosine in concert with their counterparts, protein tyrosine kinases. The important roles which PTPases play in regulating intracellular signalling and, ultimately, biological function along with the recent availability of information regarding their structural features has highlighted them as potential targets for pharmacological modulation. This is demonstrated by the increased level of activity directed towards the identification of novel small-molecule PTPase inhibitors. The rationale and potential utility of this drug discovery approach is discussed here, with particular emphasis on its application for the treatment of insulin resistance and Type 2 diabetes.
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Affiliation(s)
- J L Evans
- Diabetes Program, SUGEN, Inc., 230 East Grand Avenue, San Francisco, CA 94080, USA.
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37
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Kapoor GS, Zhan Y, Johnson GR, O'Rourke DM. Distinct domains in the SHP-2 phosphatase differentially regulate epidermal growth factor receptor/NF-kappaB activation through Gab1 in glioblastoma cells. Mol Cell Biol 2004; 24:823-36. [PMID: 14701753 PMCID: PMC343802 DOI: 10.1128/mcb.24.2.823-836.2004] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The transcription factor nuclear factor kappaB (NF-kappaB) plays an important role in inflammation and cancer, is activated by a variety of stimuli including tumor necrosis factor alpha, interleukin-1, UV irradiation, and viruses, as well as receptor tyrosine kinases, such as epidermal growth factor receptor (EGFR). Although previous studies suggest that EGFR can induce NF-kappaB, the mechanism of this activation remains unknown. In this study, we identify the components of the EGFR-induced signalosome in human glioblastoma cells required to regulate NF-kappaB activation. Immunoprecipitation analyses with ErbB-modulated cells indicate that association between SHP-2 and Grb2-associated binder 1 (Gab1) is the critical step in the formation of the signalosome linking EGFR to NF-kappaB activation. We also show that EGFR-induced NF-kappaB activation is mediated by the PI3-kinase/Akt activation loop. Overexpression of SHP-2, Gab1, and myristoylated Akt significantly upregulated NF-kappaB transcriptional activity and DNA binding activity in glioblastoma cells. Interestingly, overexpression of either one of the two SH2 domain mutants of SHP-2, R32E or R138E, slightly reduced NF-kappaB activity relative to that of wild-type SHP-2, indicating that the SH2 domains of SHP-2 are required for EGFR-induced NF-kappaB activation. On the other hand, ectopic overexpression of either a Gab1 mutant incapable of binding to SHP-2 (Y627F) or a phosphatase-inactive SHP-2 mutant (C459S) caused a significant increase in NF-kappaB activity. Moreover, SHP-2 C459S-expressing cells displayed higher Gab1 phosphotyrosine content, suggesting that SHP-2 regulates Gab1 phosphorylation through its phosphatase domain, which confers a negative regulatory effect on NF-kappaB activity. These results indicate that SHP-2/Gab1 association is critical for linking EGFR to NF-kappaB transcriptional activity via the PI3-kinase/Akt signaling axis in glioblastoma cells and that SHP-2 acts as a dual regulator of NF-kappaB activation.
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Affiliation(s)
- Gurpreet S Kapoor
- Department of Neurosurgery, University of Pennsylvania School of Medicine, 36th and Hamilton Walk, Philadelphia, PA 19104, USA
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38
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Le HT, Ponniah S, Pallen CJ. Insulin signaling and glucose homeostasis in mice lacking protein tyrosine phosphatase α. Biochem Biophys Res Commun 2004; 314:321-9. [PMID: 14733908 DOI: 10.1016/j.bbrc.2003.12.087] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Studies in cultured cells have implicated protein tyrosine phosphatase alpha (PTPalpha) as a potential regulator of insulin signaling. The physiological role of PTPalpha in insulin action was investigated using gene-targeted mice deficient in PTPalpha. PTPalpha-null animals had normal body weights and circulating levels of glucose and insulin in random fed and fasted states. In glucose and insulin tolerance tests, their efficiency of blood glucose clearance was comparable to wild-type mice. Kinetics and extents of insulin-stimulated insulin receptor and IRS-1 tyrosine phosphorylation were similar in wild-type and PTPalpha(-/-) liver, muscle, and adipose tissue. However, the association of IRS-1 and PI 3-K was altered in PTPalpha(-/-) liver, with increased insulin-independent and reduced insulin-stimulated association compared to wild-type samples. This did not affect activation of the downstream signaling effector Akt. Our data indicate that PTPalpha is not a negative regulator of insulin signaling and does not perform an essential role in mediating the physiological action of insulin.
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Affiliation(s)
- Hoa T Le
- Department of Pathology and Laboratory Medicine, British Columbia Research Institute for Children's and Women's Health, University of British Columbia, V5Z 4H4 Vancouver, BC, Canada
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39
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Asante-Appiah E, Kennedy BP. Protein tyrosine phosphatases: the quest for negative regulators of insulin action. Am J Physiol Endocrinol Metab 2003; 284:E663-70. [PMID: 12626322 DOI: 10.1152/ajpendo.00462.2002] [Citation(s) in RCA: 124] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Type 2 diabetes is increasing at an alarming rate worldwide, and there has been a considerable effort in several laboratories to identify suitable targets for the design of drugs against the disease. To this end, the protein tyrosine phosphatases that attenuate insulin signaling by dephosphorylating the insulin receptor (IR) have been actively pursued. This is because inhibiting the phosphatases would be expected to prolong insulin signaling and thereby facilitate glucose uptake and, presumably, result in a lowering of blood glucose. Targeting the IR protein tyrosine phosphatase, therefore, has the potential to be a significant disease-modifying strategy. Several protein tyrosine phosphatases (PTPs) have been implicated in the dephosphorylation of the IR. These phosphatases include PTPalpha, LAR, CD45, PTPepsilon, SHP2, and PTP1B. In most cases, there is evidence for and against the involvement of the phosphatases in insulin signaling. The most convincing data, however, support a critical role for PTP1B in insulin action. PTP1B knockout mice are not only insulin sensitive but also maintain euglycemia (in the fed state), with one-half the level of insulin observed in wild-type littermates. Interestingly, these mice are also resistant to diet-induced obesity when fed a high-fat diet. The insulin-sensitive phenotype of the PTP1B knockout mouse is reproduced when the phosphatase is also knocked down with an antisense oligonucleotide in obese mice. Thus PTP1B appears to be a very attractive candidate for the design of drugs for type 2 diabetes and obesity.
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Affiliation(s)
- Ernest Asante-Appiah
- Department of Biochemistry and Molecular Biology, Merck Frosst Center for Therapeutic Research, Pointe-Claire - Dorval, Quebec, Canada H9R 4P8
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40
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Abstract
The incidence of type 2 diabetes mellitus (T2D) and obesity is increasing rapidly worldwide, reaching epidemic proportions. Insulin resistance is a key feature in both conditions and plays an important pathophysiological role. Over the last two decades a central role in the origin of insulin resistance has emerged for defects in the intracellular insulin signaling cascade leading to glucose uptake. Herein, we will 1) review insulin signaling pathways leading to glucose uptake, 2) review mouse models of insulin resistance that demonstrate the pathophysiologic importance of specific defects of these pathways and 3) discuss the molecular basis for insulin resistance in some human disease states known to be associated with insulin resistance. Finally, we will briefly mention some novel treatment targets for T2D stemming from this knowledge.
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Affiliation(s)
- Peter Vollenweider
- Department of Internal Medicine, Centre Hospitalier Universitaire Vaudois, Lausanne, Switzerland.
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41
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Qu CK. Role of the SHP-2 tyrosine phosphatase in cytokine-induced signaling and cellular response. BIOCHIMICA ET BIOPHYSICA ACTA 2002; 1592:297-301. [PMID: 12421673 DOI: 10.1016/s0167-4889(02)00322-1] [Citation(s) in RCA: 100] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Cytokines and growth factors are important extracellular regulatory proteins. They exert their biological functions through binding to their cognate receptors on the cell surface and triggering intracellular signaling cascades. However, the intracellular signaling mechanisms of cytokines and growth factors are not well understood. Accumulating evidence has shown that protein phosphorylation and dephosphorylation carried out by protein kinases and protein phosphatases are fundamental biochemical events in intracellular signal transduction. SHP-2, a Src homology (SH) 2 domain-containing protein tyrosine phosphatase (PTP), is widely involved in a variety of signaling pathways triggered by cytokines and growth factors, including the MAP kinase, Jak-Stat, and PI3 kinase pathways. Recent studies have clearly demonstrated that this phosphatase plays an important role in transducing signals relayed from the cell surface to the nucleus, and is a critical intracellular regulator in cytokine and growth factor-induced cell survival, proliferation, and differentiation.
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Affiliation(s)
- Cheng-Kui Qu
- Department of Hematopoiesis, Jerome H. Holland Laboratory, American Red Cross, Rockville, MD 20855, USA.
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42
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Tartaglia M, Kalidas K, Shaw A, Song X, Musat DL, van der Burgt I, Brunner HG, Bertola DR, Crosby A, Ion A, Kucherlapati RS, Jeffery S, Patton MA, Gelb BD. PTPN11 mutations in Noonan syndrome: molecular spectrum, genotype-phenotype correlation, and phenotypic heterogeneity. Am J Hum Genet 2002; 70:1555-63. [PMID: 11992261 PMCID: PMC379142 DOI: 10.1086/340847] [Citation(s) in RCA: 497] [Impact Index Per Article: 22.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2002] [Accepted: 03/21/2002] [Indexed: 01/20/2023] Open
Abstract
Noonan syndrome (NS) is a developmental disorder characterized by facial dysmorphia, short stature, cardiac defects, and skeletal malformations. We recently demonstrated that mutations in PTPN11, the gene encoding the non-receptor-type protein tyrosine phosphatase SHP-2 (src homology region 2-domain phosphatase-2), cause NS, accounting for approximately 50% of cases of this genetically heterogeneous disorder in a small cohort. All mutations were missense changes and clustered at the interacting portions of the amino-terminal src-homology 2 (N-SH2) and protein tyrosine phosphatase (PTP) domains. A gain of function was postulated as a mechanism for the disease. Here, we report the spectrum and distribution of PTPN11 mutations in a large, well-characterized cohort with NS. Mutations were found in 54 of 119 (45%) unrelated individuals with sporadic or familial NS. There was a significantly higher prevalence of mutations among familial cases than among sporadic ones. All defects were missense, and several were recurrent. The vast majority of mutations altered amino acid residues located in or around the interacting surfaces of the N-SH2 and PTP domains, but defects also affected residues in the C-SH2 domain, as well as in the peptide linking the N-SH2 and C-SH2 domains. Genotype-phenotype analysis revealed that pulmonic stenosis was more prevalent among the group of subjects with NS who had PTPN11 mutations than it was in the group without them (70.6% vs. 46.2%; P<.01), whereas hypertrophic cardiomyopathy was less prevalent among those with PTPN11 mutations (5.9% vs. 26.2%; P<.005). The prevalence of other congenital heart malformations, short stature, pectus deformity, cryptorchidism, and developmental delay did not differ between the two groups. A PTPN11 mutation was identified in a family inheriting Noonan-like/multiple giant-cell lesion syndrome, extending the phenotypic range of disease associated with this gene.
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Affiliation(s)
- Marco Tartaglia
- Departments of Pediatrics and Human Genetics, Mount Sinai School of Medicine, New York; Laboratorio di Metabolismo e Biochimica Patologica, Istituto Superiore di Sanità, Rome; Department of Medical Genetics, St. George's Hospital Medical School, London; Department of Human Genetics, University Medical Centre, Nijmegen, The Netherlands; Department of Pediatrics, University of São Paulo, São Paulo, Brazil; and Department of Genetics, Harvard Medical School, Boston
| | - Kamini Kalidas
- Departments of Pediatrics and Human Genetics, Mount Sinai School of Medicine, New York; Laboratorio di Metabolismo e Biochimica Patologica, Istituto Superiore di Sanità, Rome; Department of Medical Genetics, St. George's Hospital Medical School, London; Department of Human Genetics, University Medical Centre, Nijmegen, The Netherlands; Department of Pediatrics, University of São Paulo, São Paulo, Brazil; and Department of Genetics, Harvard Medical School, Boston
| | - Adam Shaw
- Departments of Pediatrics and Human Genetics, Mount Sinai School of Medicine, New York; Laboratorio di Metabolismo e Biochimica Patologica, Istituto Superiore di Sanità, Rome; Department of Medical Genetics, St. George's Hospital Medical School, London; Department of Human Genetics, University Medical Centre, Nijmegen, The Netherlands; Department of Pediatrics, University of São Paulo, São Paulo, Brazil; and Department of Genetics, Harvard Medical School, Boston
| | - Xiaoling Song
- Departments of Pediatrics and Human Genetics, Mount Sinai School of Medicine, New York; Laboratorio di Metabolismo e Biochimica Patologica, Istituto Superiore di Sanità, Rome; Department of Medical Genetics, St. George's Hospital Medical School, London; Department of Human Genetics, University Medical Centre, Nijmegen, The Netherlands; Department of Pediatrics, University of São Paulo, São Paulo, Brazil; and Department of Genetics, Harvard Medical School, Boston
| | - Dan L. Musat
- Departments of Pediatrics and Human Genetics, Mount Sinai School of Medicine, New York; Laboratorio di Metabolismo e Biochimica Patologica, Istituto Superiore di Sanità, Rome; Department of Medical Genetics, St. George's Hospital Medical School, London; Department of Human Genetics, University Medical Centre, Nijmegen, The Netherlands; Department of Pediatrics, University of São Paulo, São Paulo, Brazil; and Department of Genetics, Harvard Medical School, Boston
| | - Ineke van der Burgt
- Departments of Pediatrics and Human Genetics, Mount Sinai School of Medicine, New York; Laboratorio di Metabolismo e Biochimica Patologica, Istituto Superiore di Sanità, Rome; Department of Medical Genetics, St. George's Hospital Medical School, London; Department of Human Genetics, University Medical Centre, Nijmegen, The Netherlands; Department of Pediatrics, University of São Paulo, São Paulo, Brazil; and Department of Genetics, Harvard Medical School, Boston
| | - Han G. Brunner
- Departments of Pediatrics and Human Genetics, Mount Sinai School of Medicine, New York; Laboratorio di Metabolismo e Biochimica Patologica, Istituto Superiore di Sanità, Rome; Department of Medical Genetics, St. George's Hospital Medical School, London; Department of Human Genetics, University Medical Centre, Nijmegen, The Netherlands; Department of Pediatrics, University of São Paulo, São Paulo, Brazil; and Department of Genetics, Harvard Medical School, Boston
| | - Débora R. Bertola
- Departments of Pediatrics and Human Genetics, Mount Sinai School of Medicine, New York; Laboratorio di Metabolismo e Biochimica Patologica, Istituto Superiore di Sanità, Rome; Department of Medical Genetics, St. George's Hospital Medical School, London; Department of Human Genetics, University Medical Centre, Nijmegen, The Netherlands; Department of Pediatrics, University of São Paulo, São Paulo, Brazil; and Department of Genetics, Harvard Medical School, Boston
| | - Andrew Crosby
- Departments of Pediatrics and Human Genetics, Mount Sinai School of Medicine, New York; Laboratorio di Metabolismo e Biochimica Patologica, Istituto Superiore di Sanità, Rome; Department of Medical Genetics, St. George's Hospital Medical School, London; Department of Human Genetics, University Medical Centre, Nijmegen, The Netherlands; Department of Pediatrics, University of São Paulo, São Paulo, Brazil; and Department of Genetics, Harvard Medical School, Boston
| | - Andra Ion
- Departments of Pediatrics and Human Genetics, Mount Sinai School of Medicine, New York; Laboratorio di Metabolismo e Biochimica Patologica, Istituto Superiore di Sanità, Rome; Department of Medical Genetics, St. George's Hospital Medical School, London; Department of Human Genetics, University Medical Centre, Nijmegen, The Netherlands; Department of Pediatrics, University of São Paulo, São Paulo, Brazil; and Department of Genetics, Harvard Medical School, Boston
| | - Raju S. Kucherlapati
- Departments of Pediatrics and Human Genetics, Mount Sinai School of Medicine, New York; Laboratorio di Metabolismo e Biochimica Patologica, Istituto Superiore di Sanità, Rome; Department of Medical Genetics, St. George's Hospital Medical School, London; Department of Human Genetics, University Medical Centre, Nijmegen, The Netherlands; Department of Pediatrics, University of São Paulo, São Paulo, Brazil; and Department of Genetics, Harvard Medical School, Boston
| | - Steve Jeffery
- Departments of Pediatrics and Human Genetics, Mount Sinai School of Medicine, New York; Laboratorio di Metabolismo e Biochimica Patologica, Istituto Superiore di Sanità, Rome; Department of Medical Genetics, St. George's Hospital Medical School, London; Department of Human Genetics, University Medical Centre, Nijmegen, The Netherlands; Department of Pediatrics, University of São Paulo, São Paulo, Brazil; and Department of Genetics, Harvard Medical School, Boston
| | - Michael A. Patton
- Departments of Pediatrics and Human Genetics, Mount Sinai School of Medicine, New York; Laboratorio di Metabolismo e Biochimica Patologica, Istituto Superiore di Sanità, Rome; Department of Medical Genetics, St. George's Hospital Medical School, London; Department of Human Genetics, University Medical Centre, Nijmegen, The Netherlands; Department of Pediatrics, University of São Paulo, São Paulo, Brazil; and Department of Genetics, Harvard Medical School, Boston
| | - Bruce D. Gelb
- Departments of Pediatrics and Human Genetics, Mount Sinai School of Medicine, New York; Laboratorio di Metabolismo e Biochimica Patologica, Istituto Superiore di Sanità, Rome; Department of Medical Genetics, St. George's Hospital Medical School, London; Department of Human Genetics, University Medical Centre, Nijmegen, The Netherlands; Department of Pediatrics, University of São Paulo, São Paulo, Brazil; and Department of Genetics, Harvard Medical School, Boston
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43
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Cheng A, Dubé N, Gu F, Tremblay ML. Coordinated action of protein tyrosine phosphatases in insulin signal transduction. EUROPEAN JOURNAL OF BIOCHEMISTRY 2002; 269:1050-9. [PMID: 11856336 DOI: 10.1046/j.0014-2956.2002.02756.x] [Citation(s) in RCA: 147] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Insulin is the principal regulatory hormone involved in the tight regulation of fuel metabolism. In response to blood glucose levels, it is secreted by the beta cells of the pancreas and exerts its effects by binding to cell surface receptors that are present on virtually all cell types and tissues. In humans, perturbations in insulin function and/or secretion lead to diabetes mellitus, a severe disorder primarily characterized by an inability to maintain blood glucose homeostasis. Furthermore, it is estimated that 90-95% of diabetic patients exhibit resistance to insulin action. Thus an understanding of insulin signal transduction and insulin resistance at the molecular level is crucial to the understanding of the pathogenesis of this disease. The insulin receptor (IR) is a transmembrane tyrosine kinase that becomes activated upon ligand binding. Consequently, the receptor and its downstream substrates become tyrosine phosphorylated. This activates a series of intracellular signaling cascades which coordinately initiate the appropriate biological response. One important mechanism by which insulin signaling is regulated involves the protein tyrosine phosphatases (PTPs), which may either act on the IR itself and/or its substrates. Two well characterized examples include leuckocyte antigen related (LAR) and protein tyrosine phosphatase-1B (PTP-1B). The present review will discuss the current knowledge of these two and other potential PTPs involved in the insulin signaling pathway.
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Affiliation(s)
- Alan Cheng
- Department of Biochemistry and McGill Cancer Center, McGill University, Montreal, Quebec, Canada
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44
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Tartaglia M, Mehler EL, Goldberg R, Zampino G, Brunner HG, Kremer H, van der Burgt I, Crosby AH, Ion A, Jeffery S, Kalidas K, Patton MA, Kucherlapati RS, Gelb BD. Mutations in PTPN11, encoding the protein tyrosine phosphatase SHP-2, cause Noonan syndrome. Nat Genet 2001; 29:465-8. [PMID: 11704759 DOI: 10.1038/ng772] [Citation(s) in RCA: 1144] [Impact Index Per Article: 49.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Noonan syndrome (MIM 163950) is an autosomal dominant disorder characterized by dysmorphic facial features, proportionate short stature and heart disease (most commonly pulmonic stenosis and hypertrophic cardiomyopathy). Webbed neck, chest deformity, cryptorchidism, mental retardation and bleeding diatheses also are frequently associated with this disease. This syndrome is relatively common, with an estimated incidence of 1 in 1,000-2,500 live births. It has been mapped to a 5-cM region (NS1) [corrected] on chromosome 12q24.1, and genetic heterogeneity has also been documented. Here we show that missense mutations in PTPN11 (MIM 176876)-a gene encoding the nonreceptor protein tyrosine phosphatase SHP-2, which contains two Src homology 2 (SH2) domains-cause Noonan syndrome and account for more than 50% of the cases that we examined. All PTPN11 missense mutations cluster in interacting portions of the amino N-SH2 domain and the phosphotyrosine phosphatase domains, which are involved in switching the protein between its inactive and active conformations. An energetics-based structural analysis of two N-SH2 mutants indicates that in these mutants there may be a significant shift of the equilibrium favoring the active conformation. This implies that they are gain-of-function changes and that the pathogenesis of Noonan syndrome arises from excessive SHP-2 activity.
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Affiliation(s)
- M Tartaglia
- Department of Pediatrics, Mount Sinai School of Medicine, New York, New York 10029, USA.
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Abstract
Protein tyrosine phosphatases (PTPs), the enzymes that dephosphorylate tyrosyl phosphoproteins, were initially believed to be few in number and serve a 'housekeeping' role in signal transduction. Recent work indicates that this is totally incorrect. Instead, PTPs comprise a large superfamily whose members play critical roles in a wide variety of cellular processes. Moreover, PTPs exhibit exquisite substrate specificity in vivo. Recent evidence has led us to propose that members of the PTP family achieve selectivity through different combinations of specific targeting strategies and intrinsic catalytic domain specificity.
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Affiliation(s)
- N K Tonks
- Cold Spring Harbor Laboratory, 1 Bungtown Road, Cold Spring Harbor, New York 11724, USA.
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Abstract
Cellular biological activities are tightly controlled by intracellular signaling processes initiated by extracellular signals. Protein tyrosine phosphatases, which remove phosphate groups from phosphorylated signaling molecules, play equally important tyrosine roles as protein tyrosine kinases in signal transduction. SHP-2, a cytoplasmic SH2 domain containing protein tyrosine phosphatase, is involved in the signaling pathways of a variety of growth factors and cytokines. Recent studies have clearly demonstrated that this phosphatase plays an important role in transducing signal relay from the cell surface to the nucleus, and is a critical intracellular regulator in mediating cell proliferation and differentiation.
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Affiliation(s)
- C K Qu
- Department of Hematopoiesis, American Red Cross, Rockville, MD 20855, USA.
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47
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Aoki Y, Huang Z, Thomas SS, Bhide PG, Huang I, Moskowitz MA, Reeves SA. Increased susceptibility to ischemia-induced brain damage in transgenic mice overexpressing a dominant negative form of SHP2. FASEB J 2000; 14:1965-73. [PMID: 11023980 DOI: 10.1096/fj.00-0105com] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Cell culture studies have established SH2 domain-containing protein tyrosine phosphatase-2 (SHP2) as an important factor in growth factor and cytokine-activated signaling pathways. However, the significance of SHP2 in the mammalian central nervous system (CNS) is not known since early embryonic lethality occurs in shp2 null mice. To bypass this embryonic lethality, transgenic animals containing a catalytically inactive mutant of SHP2 (SHP2-CS) under the control of a nestin intron II/thymidine kinase minimal promoter were generated. In the developing CNS of these animals, although high-level transgene expression was detected in the neuroepithelium, there was no obvious abnormality in progenitor cell proliferation or migration. In the adult brain, high-level transgene expression was detected in the subventricular zone, rostral migratory stream, dentate gyrus of hippocampus, and cerebellum. Because SHP2 function is likely important in cell survival pathways, we used a focal cerebral ischemia model to examined whether SHP2 is important during CNS injury. Ischemia-induced damage and neuronal death was found to be significantly greater in nestin-SHP2-CS mice than in wild-type littermates. These findings indicate that SHP2 is a required factor in signaling pathway(s) important for neuronal survival.
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Affiliation(s)
- Y Aoki
- CNS Signaling Laboratory, Molecular Neuro-Oncology, Massachusetts General Hospital, Charlestown, MA 02129, USA
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48
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Boyd Y, Blair HJ, Cunliffe P, Masson WK, Reed V. A phenotype map of the mouse X chromosome: models for human X-linked disease. Genome Res 2000; 10:277-92. [PMID: 10720569 DOI: 10.1101/gr.10.3.277] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
The identification of many of the transcribed genes in man and mouse is being achieved by large scale sequencing of expressed sequence tags (ESTs). Attention is now being turned to elucidating gene function and many laboratories are looking to the mouse as a model system for this phase of the genome project. Mouse mutants have long been used as a means of investigating gene function and disease pathogenesis, and recently, several large mutagenesis programs have been initiated to fulfill the burgeoning demand of functional genomics research. Nevertheless, there is a substantial existing mouse mutant resource that can be used immediately. This review summarizes the available information about the loci encoding X-linked phenotypic mutants and variants, including 40 classical mutants and 40 that have arisen from gene targeting.
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Affiliation(s)
- Y Boyd
- Medical Research Council (MRC) Mammalian Genetics Unit, Harwell, Oxon OX11 0RD UK.
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Chen B, Bronson RT, Klaman LD, Hampton TG, Wang JF, Green PJ, Magnuson T, Douglas PS, Morgan JP, Neel BG. Mice mutant for Egfr and Shp2 have defective cardiac semilunar valvulogenesis. Nat Genet 2000; 24:296-9. [PMID: 10700187 DOI: 10.1038/73528] [Citation(s) in RCA: 227] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Atrioventricular and semilunar valve abnormalities are common birth defects, but how cardiac valvulogenesis is directed remains largely unknown. During studies of genetic interaction between Egfr, encoding the epidermal growth factor receptor, and Ptpn11, encoding the protein-tyrosine-phosphatase Shp2, we discovered that Egfr is required for semilunar, but not atrioventricular, valve development. Although unnoticed in earlier studies, mice homozygous for the hypomorphic Egfr allele waved-2 (Egfrwa2/wa2) exhibit semilunar valve enlargement resulting from over-abundant mesenchymal cells. Egfr-/- mice (CD1 background) have similar defects. The penetrance and severity of the defects in Egfrwa2/wa2 mice are enhanced by heterozygosity for a targeted mutation of exon 2 of Ptpn11 (ref. 3). Compound (Egfrwa2/wa2:Ptpn11+/-) mutant mice also show premature lethality. Electrocardiography, echocardiography and haemodynamic analyses showed that affected mice develop aortic stenosis and regurgitation. Our results identify the Egfr and Shp2 as components of a growth-factor signalling pathway required specifically for semilunar valvulogenesis, support the hypothesis that Shp2 is required for Egfr signalling in vivo, and provide an animal model for aortic valve disease.
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Affiliation(s)
- B Chen
- Cancer Biology Program, Hematology/Oncology Division, Boston, Massachusetts, USA
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50
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The contribution of defects in insulin signaling in skeletal muscle to insulin resistance and type 2 diabetes. ACTA ACUST UNITED AC 2000. [DOI: 10.1016/s1064-6000(00)80004-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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