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Zhu J, Hu Z, Luo Y, Liu Y, Luo W, Du X, Luo Z, Hu J, Peng S. Diabetic peripheral neuropathy: pathogenetic mechanisms and treatment. Front Endocrinol (Lausanne) 2024; 14:1265372. [PMID: 38264279 PMCID: PMC10803883 DOI: 10.3389/fendo.2023.1265372] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/22/2023] [Accepted: 12/14/2023] [Indexed: 01/25/2024] Open
Abstract
Diabetic peripheral neuropathy (DPN) refers to the development of peripheral nerve dysfunction in patients with diabetes when other causes are excluded. Diabetic distal symmetric polyneuropathy (DSPN) is the most representative form of DPN. As one of the most common complications of diabetes, its prevalence increases with the duration of diabetes. 10-15% of newly diagnosed T2DM patients have DSPN, and the prevalence can exceed 50% in patients with diabetes for more than 10 years. Bilateral limb pain, numbness, and paresthesia are the most common clinical manifestations in patients with DPN, and in severe cases, foot ulcers can occur, even leading to amputation. The etiology and pathogenesis of diabetic neuropathy are not yet completely clarified, but hyperglycemia, disorders of lipid metabolism, and abnormalities in insulin signaling pathways are currently considered to be the initiating factors for a range of pathophysiological changes in DPN. In the presence of abnormal metabolic factors, the normal structure and function of the entire peripheral nervous system are disrupted, including myelinated and unmyelinated nerve axons, perikaryon, neurovascular, and glial cells. In addition, abnormalities in the insulin signaling pathway will inhibit neural axon repair and promote apoptosis of damaged cells. Here, we will discuss recent advances in the study of DPN mechanisms, including oxidative stress pathways, mechanisms of microvascular damage, mechanisms of damage to insulin receptor signaling pathways, and other potential mechanisms associated with neuroinflammation, mitochondrial dysfunction, and cellular oxidative damage. Identifying the contributions from each pathway to neuropathy and the associations between them may help us to further explore more targeted screening and treatment interventions.
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Affiliation(s)
- Jinxi Zhu
- Department of Anesthesiology, The Second Affiliated Hospital of Nanchang University, Nanchang, Jiangxi, China
- The Second Clinical Medical College of Nanchang University, The Second Affiliated Hospital of Nanchang University, Nanchang, Jiangxi, China
| | - Ziyan Hu
- Department of Anesthesiology, The Second Affiliated Hospital of Nanchang University, Nanchang, Jiangxi, China
- The Second Clinical Medical College of Nanchang University, The Second Affiliated Hospital of Nanchang University, Nanchang, Jiangxi, China
| | - Yifan Luo
- Department of Anesthesiology, The Second Affiliated Hospital of Nanchang University, Nanchang, Jiangxi, China
| | - Yinuo Liu
- Department of Anesthesiology, The Second Affiliated Hospital of Nanchang University, Nanchang, Jiangxi, China
| | - Wei Luo
- Department of Sports Medicine, Huashan Hospital, Fudan University, Shanghai, China
| | - Xiaohong Du
- Department of Anesthesiology, The Second Affiliated Hospital of Nanchang University, Nanchang, Jiangxi, China
| | - Zhenzhong Luo
- Department of Anesthesiology, The Second Affiliated Hospital of Nanchang University, Nanchang, Jiangxi, China
| | - Jialing Hu
- Department of Emergency Medicine, The Second Affiliated Hospital of Nanchang University, Nanchang, Jiangxi, China
| | - Shengliang Peng
- Department of Anesthesiology, The Second Affiliated Hospital of Nanchang University, Nanchang, Jiangxi, China
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2
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Ma Y, Zhai D, Zhang W, Zhang H, Dong L, Zhou Y, Feng D, Zheng Y, Wang T, Mao C, Wang X. Down-regulation of long non-coding RNA MEG3 promotes Schwann cell proliferation and migration and repairs sciatic nerve injury in rats. J Cell Mol Med 2020; 24:7460-7469. [PMID: 32436312 PMCID: PMC7339166 DOI: 10.1111/jcmm.15368] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2019] [Revised: 02/01/2020] [Accepted: 04/22/2020] [Indexed: 12/18/2022] Open
Abstract
Peripheral nerve injury and regeneration are complex processes and involve multiple molecular and signalling components. However, the involvement of long non-coding RNA (lncRNA) in this process is not fully clarified. In this study, we evaluated the expression of the lncRNA maternally expressed gene 3 (MEG3) in rats after sciatic nerve transection and explored its potential mechanisms. The expression of lncRNA MEG3 was up-regulated following sciatic nerve injury and observed in Schwann cells (SCs). The down-regulation of lncRNA MEG3 in SCs enhanced the proliferation and migration of SCs via the PTEN/PI3K/AKT pathway. The silencing of lncRNA MEG3 promoted the migration of SCs and axon outgrowth in rats after sciatic nerve transection and facilitated rat nerve regeneration and functional recovery. Our findings indicated that lncRNA MEG3 may be involved in nerve injury and injured nerve regeneration in rats with sciatic nerve defects by regulating the proliferation and migration of SCs. This gene may provide a potential therapeutic target for improving peripheral nerve injury.
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Affiliation(s)
- Yongbin Ma
- Department of Central Laboratory, The Affiliated Hospital of Jiangsu University, Zhenjiang, China.,Department of Pathogen Biology & Immunology, Jiangsu Key Laboratory of Pathogen Biology, Nanjing Medical University, Nanjing, China.,Department of Neurology Laboratory, Jintan Hospital, Jiangsu University, Jintan, China
| | - Dongwang Zhai
- Department of Clinical Laboratory, Aerospace Center Hospital, Peking University, Beijing, China
| | - Wenzhe Zhang
- Department of Central Laboratory, The Affiliated Hospital of Jiangsu University, Zhenjiang, China
| | - Huanyan Zhang
- Department of Neurology Laboratory, Jintan Hospital, Jiangsu University, Jintan, China
| | - Liyang Dong
- Department of Nuclear Medicine and Institute of Oncology, The Affiliated Hospital of Jiangsu University, Zhenjiang, China
| | - Yuepeng Zhou
- Department of Nuclear Medicine and Institute of Oncology, The Affiliated Hospital of Jiangsu University, Zhenjiang, China
| | - Dingqi Feng
- Department of Central Laboratory, The Affiliated Hospital of Jiangsu University, Zhenjiang, China
| | - Yu Zheng
- Department of Central Laboratory, The Affiliated Hospital of Jiangsu University, Zhenjiang, China
| | - Ting Wang
- Department of Central Laboratory, The Affiliated Hospital of Jiangsu University, Zhenjiang, China
| | - Chaoming Mao
- Department of Nuclear Medicine and Institute of Oncology, The Affiliated Hospital of Jiangsu University, Zhenjiang, China
| | - Xuefeng Wang
- Department of Central Laboratory, The Affiliated Hospital of Jiangsu University, Zhenjiang, China.,Department of Neurology Laboratory, Jintan Hospital, Jiangsu University, Jintan, China
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3
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Zhou L, Shao CY, Xie YJ, Wang N, Xu SM, Luo BY, Wu ZY, Ke YH, Qiu M, Shen Y. Gab1 mediates PDGF signaling and is essential to oligodendrocyte differentiation and CNS myelination. eLife 2020; 9:52056. [PMID: 31944179 PMCID: PMC6984811 DOI: 10.7554/elife.52056] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2019] [Accepted: 01/14/2020] [Indexed: 02/06/2023] Open
Abstract
Oligodendrocytes (OLs) myelinate axons and provide electrical insulation and trophic support for neurons in the central nervous system (CNS). Platelet-derived growth factor (PDGF) is critical for steady-state number and differentiation of oligodendrocyte precursor cells (OPCs), but its downstream targets are unclear. Here, we show for the first time that Gab1, an adaptor protein of receptor tyrosine kinase, is specifically expressed in OL lineage cells and is an essential effector of PDGF signaling in OPCs in mice. Gab1 is downregulated by PDGF stimulation and upregulated during OPC differentiation. Conditional deletions of Gab1 in OLs cause CNS hypomyelination by affecting OPC differentiation. Moreover, Gab1 binds to downstream GSK3β and regulated its activity, and thereby affects the nuclear accumulation of β-catenin and the expression of a number of transcription factors critical to myelination. Our work uncovers a novel downstream target of PDGF signaling, which is essential to OPC differentiation and CNS myelination.
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Affiliation(s)
- Liang Zhou
- Department of Physiology of First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China.,Department of Neurology of First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China.,NHC and CAMS Key Laboratory of Medical Neurobiology, Zhejiang University School of Medicine, Hangzhou, China.,Key Laboratory of Brain Science, Guizhou Institution of Higher Education, Zunyi Medical University, Zunyi, China
| | - Chong-Yu Shao
- Department of Physiology of First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China.,Department of Neurology of First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China.,NHC and CAMS Key Laboratory of Medical Neurobiology, Zhejiang University School of Medicine, Hangzhou, China
| | - Ya-Jun Xie
- Department of Physiology of First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China.,Department of Neurology of First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China.,NHC and CAMS Key Laboratory of Medical Neurobiology, Zhejiang University School of Medicine, Hangzhou, China
| | - Na Wang
- School of Medicine, Zhejiang University City College, Hangzhou, China
| | - Si-Min Xu
- Department of Physiology of First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China.,Department of Neurology of First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China.,NHC and CAMS Key Laboratory of Medical Neurobiology, Zhejiang University School of Medicine, Hangzhou, China
| | - Ben-Yan Luo
- Department of Physiology of First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China.,Department of Neurology of First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China.,NHC and CAMS Key Laboratory of Medical Neurobiology, Zhejiang University School of Medicine, Hangzhou, China
| | - Zhi-Ying Wu
- Department of Neurology and Research Center of Neurology in Second Affiliated Hospital, Key Laboratory of Medical Neurobiology of Zhejiang Province, Zhejiang University School of Medicine, Hangzhou, China
| | - Yue Hai Ke
- Department of Pathology and Pathophysiology, Zhejiang University School of Medicine, Hangzhou, China
| | - Mengsheng Qiu
- Institute of Life Sciences, Zhejiang Key Laboratory of Organ Development and Regeneration, College of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou, China
| | - Ying Shen
- Department of Physiology of First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China.,Department of Neurology of First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China.,NHC and CAMS Key Laboratory of Medical Neurobiology, Zhejiang University School of Medicine, Hangzhou, China
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4
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Lu NN, Tan C, Sun NH, Shao LX, Liu XX, Gao YP, Tao RR, Jiang Q, Wang CK, Huang JY, Zhao K, Wang GF, Liu ZR, Fukunaga K, Lu YM, Han F. Cholinergic Grb2-Associated-Binding Protein 1 Regulates Cognitive Function. Cereb Cortex 2019; 28:2391-2404. [PMID: 28591834 DOI: 10.1093/cercor/bhx141] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2016] [Accepted: 05/21/2017] [Indexed: 12/21/2022] Open
Abstract
Grb2-associated-binding protein 1 (Gab1) is a docking/scaffolding molecule known to play an important role in cell growth and survival. Here, we report that Gab1 is decreased in cholinergic neurons in Alzheimer's disease (AD) patients and in a mouse model of AD. In mice, selective ablation of Gab1 in cholinergic neurons in the medial septum impaired learning and memory and hippocampal long-term potentiation. Gab1 ablation also inhibited SK channels, leading to an increase in firing in septal cholinergic neurons. Gab1 overexpression, on the other hand, improved cognitive function and restored hippocampal CaMKII autorphosphorylation in AD mice. These results suggest that Gab1 plays an important role in the pathophysiology of AD and may represent a novel therapeutic target for diseases involving cholinergic dysfunction.
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Affiliation(s)
- Nan-Nan Lu
- College of Pharmaceutical Sciences, Institute of Pharmacology and Toxicology, Zhejiang University, Hangzhou, Zhejiang, China
| | - Chao Tan
- College of Pharmaceutical Sciences, Institute of Pharmacology and Toxicology, Zhejiang University, Hangzhou, Zhejiang, China
| | - Ning-He Sun
- College of Pharmaceutical Sciences, Institute of Pharmacology and Toxicology, Zhejiang University, Hangzhou, Zhejiang, China
| | - Ling-Xiao Shao
- College of Pharmaceutical Sciences, Institute of Pharmacology and Toxicology, Zhejiang University, Hangzhou, Zhejiang, China
| | - Xiu-Xiu Liu
- College of Pharmaceutical Sciences, Institute of Pharmacology and Toxicology, Zhejiang University, Hangzhou, Zhejiang, China.,School of Medicine, Zhejiang University City College, Hangzhou, Zhejiang, China
| | - Yin-Ping Gao
- College of Pharmaceutical Sciences, Institute of Pharmacology and Toxicology, Zhejiang University, Hangzhou, Zhejiang, China.,School of Medicine, Zhejiang University City College, Hangzhou, Zhejiang, China
| | - Rong-Rong Tao
- College of Pharmaceutical Sciences, Institute of Pharmacology and Toxicology, Zhejiang University, Hangzhou, Zhejiang, China
| | - Quan Jiang
- College of Pharmaceutical Sciences, Institute of Pharmacology and Toxicology, Zhejiang University, Hangzhou, Zhejiang, China
| | - Cheng-Kun Wang
- College of Pharmaceutical Sciences, Institute of Pharmacology and Toxicology, Zhejiang University, Hangzhou, Zhejiang, China
| | - Ji-Yun Huang
- College of Pharmaceutical Sciences, Institute of Pharmacology and Toxicology, Zhejiang University, Hangzhou, Zhejiang, China
| | - Kui Zhao
- Department of PET Center, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
| | - Guang-Fa Wang
- Department of PET Center, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
| | - Zhi-Rong Liu
- Department of Neurology, Second Affiliated Hospital of Zhejiang University, School of Medicine, Hangzhou, Zhejiang, China
| | - Kohji Fukunaga
- Department of Pharmacology, Graduate School of Pharmaceutical Sciences, Tohoku University, Aoba-ku, Sendai, Japan
| | - Ying-Mei Lu
- School of Medicine, Zhejiang University City College, Hangzhou, Zhejiang, China.,Key Laboratory of Medical Neurobiology of Ministry of Health of China, Department of Neurobiology,Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
| | - Feng Han
- College of Pharmaceutical Sciences, Institute of Pharmacology and Toxicology, Zhejiang University, Hangzhou, Zhejiang, China
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5
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Kobayashi M, Zochodne DW. Diabetic neuropathy and the sensory neuron: New aspects of pathogenesis and their treatment implications. J Diabetes Investig 2018; 9:1239-1254. [PMID: 29533535 PMCID: PMC6215951 DOI: 10.1111/jdi.12833] [Citation(s) in RCA: 71] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/12/2018] [Revised: 02/20/2018] [Accepted: 03/03/2018] [Indexed: 12/17/2022] Open
Abstract
Diabetic polyneuropathy (DPN) continues to be generally considered as a "microvascular" complication of diabetes mellitus alongside nephropathy and retinopathy. The microvascular hypothesis, however, might be tempered by the concept that diabetes directly targets dorsal root ganglion sensory neurons. This neuron-specific concept, supported by accumulating evidence, might account for important features of DPN, such as its early sensory neuron degeneration. Diabetic sensory neurons develop neuronal atrophy alongside a series of messenger ribonucleic acid (RNA) changes related to declines in structural proteins, increases in heat shock protein, increases in the receptor for advanced glycation end-products, declines in growth factor signaling and other changes. Insulin is recognized as a potent neurotrophic factor, and insulin ligation enhances neurite outgrowth through activation of the phosphoinositide 3-kinase-protein kinase B pathway within sensory neurons and attenuates phenotypic features of experimental DPN. Several interventions, including glucagon-like peptide-1 agonism, and phosphatase and tensin homolog inhibition to activate growth signals in sensory neurons, or heat shock protein overexpression, prevent or reverse neuropathic abnormalities in experimental DPN. Diabetic sensory neurons show a unique pattern of microRNA alterations, a key element of messenger RNA silencing. For example, let-7i is widely expressed in sensory neurons, supports their growth and is depleted in experimental DPN; its replenishment improves features of DPN models. Finally, impairment of pre-messenger RNA splicing in diabetic sensory neurons including abnormal nuclear RNA metabolism and structure with loss of survival motor neuron protein, a neuron survival molecule, and overexpression of CWC22, a splicing factor, offer further novel insights. The present review addresses these new aspects of DPN sensory neurodegeneration.
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Affiliation(s)
- Masaki Kobayashi
- Department of Neurology and Neurological ScienceGraduate School of MedicineTokyo Medical and Dental UniversityTokyoJapan
- Department of NeurologyYokufukai Geriatric HospitalTokyoJapan
| | - Douglas W Zochodne
- Division of Neurology and Department of MedicineNeuroscience and Mental Health InstituteFaculty of Medicine and DentistryUniversity of AlbertaEdmontonAlbertaCanada
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6
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Marshall J, Zhou XZ, Chen G, Yang SQ, Li Y, Wang Y, Zhang ZQ, Jiang Q, Birnbaumer L, Cao C. Antidepression action of BDNF requires and is mimicked by Gαi1/3 expression in the hippocampus. Proc Natl Acad Sci U S A 2018; 115:E3549-E3558. [PMID: 29507199 PMCID: PMC5899481 DOI: 10.1073/pnas.1722493115] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Stress-related alterations in brain-derived neurotrophic factor (BDNF) expression, a neurotrophin that plays a key role in synaptic plasticity, are believed to contribute to the pathophysiology of depression. Here, we show that in a chronic mild stress (CMS) model of depression the Gαi1 and Gαi3 subunits of heterotrimeric G proteins are down-regulated in the hippocampus, a key limbic structure associated with major depressive disorder. We provide evidence that Gαi1 and Gαi3 (Gαi1/3) are required for the activation of TrkB downstream signaling pathways. In mouse embryonic fibroblasts (MEFs) and CNS neurons, Gαi1/3 knockdown inhibited BDNF-induced tropomyosin-related kinase B (TrkB) endocytosis, adaptor protein activation, and Akt-mTORC1 and Erk-MAPK signaling. Functional studies show that Gαi1 and Gαi3 knockdown decreases the number of dendrites and dendritic spines in hippocampal neurons. In vivo, hippocampal Gαi1/3 knockdown after bilateral microinjection of lentiviral constructs containing Gαi1 and Gαi3 shRNA elicited depressive behaviors. Critically, exogenous expression of Gαi3 in the hippocampus reversed depressive behaviors in CMS mice. Similar results were observed in Gαi1/Gαi3 double-knockout mice, which exhibited severe depressive behaviors. These results demonstrate that heterotrimeric Gαi1 and Gαi3 proteins are essential for TrkB signaling and that disruption of Gαi1 or Gαi3 function could contribute to depressive behaviors.
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MESH Headings
- Animals
- Brain-Derived Neurotrophic Factor/metabolism
- Dendrites/metabolism
- Dendrites/pathology
- Dendritic Spines/metabolism
- Dendritic Spines/pathology
- Depression/metabolism
- Depression/pathology
- Depressive Disorder, Major/metabolism
- Depressive Disorder, Major/pathology
- Down-Regulation
- Female
- GTP-Binding Protein alpha Subunit, Gi2/biosynthesis
- GTP-Binding Protein alpha Subunit, Gi2/genetics
- GTP-Binding Protein alpha Subunit, Gi2/metabolism
- GTP-Binding Protein alpha Subunits, Gi-Go/biosynthesis
- GTP-Binding Protein alpha Subunits, Gi-Go/genetics
- GTP-Binding Protein alpha Subunits, Gi-Go/metabolism
- Hippocampus/metabolism
- Mice
- Mice, Knockout
- Neurons/metabolism
- Neurons/pathology
- Signal Transduction/drug effects
- Stress, Physiological/physiology
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Affiliation(s)
- John Marshall
- Department of Molecular Pharmacology, Physiology, and Biotechnology, Brown University, Providence, RI 02912;
| | - Xiao-Zhong Zhou
- Jiangsu Key Laboratory of Neuropsychiatric Diseases Research, Soochow University, Suzhou 215000, China
- Institute of Neuroscience, Soochow University, Suzhou 215000, China
- Department of Orthopedics, The Second Affiliated Hospital of Soochow University, Suzhou, 215004 Jiangsu, China
| | - Gang Chen
- Department of Neurosurgery, The First Affiliated Hospital of Soochow University, Suzhou, 215006 Jiangsu, China
| | - Su-Qing Yang
- Jiangsu Key Laboratory of Neuropsychiatric Diseases Research, Soochow University, Suzhou 215000, China
- Institute of Neuroscience, Soochow University, Suzhou 215000, China
| | - Ya Li
- Jiangsu Key Laboratory of Neuropsychiatric Diseases Research, Soochow University, Suzhou 215000, China
- Institute of Neuroscience, Soochow University, Suzhou 215000, China
| | - Yin Wang
- Jiangsu Key Laboratory of Neuropsychiatric Diseases Research, Soochow University, Suzhou 215000, China
- Institute of Neuroscience, Soochow University, Suzhou 215000, China
| | - Zhi-Qing Zhang
- Jiangsu Key Laboratory of Neuropsychiatric Diseases Research, Soochow University, Suzhou 215000, China
- Institute of Neuroscience, Soochow University, Suzhou 215000, China
| | - Qin Jiang
- The Fourth School of Clinical Medicine, The Affiliated Eye Hospital, Nanjing Medical University, 210029 Nanjing, China
| | - Lutz Birnbaumer
- Neurobiology Laboratory, National Institute of Environmental Health Sciences, Research Triangle Park, NC 27709;
- School of Medical Sciences, Institute of Biomedical Research, Catholic University of Argentina, C1107AAZ Buenos Aires, Argentina
| | - Cong Cao
- Jiangsu Key Laboratory of Neuropsychiatric Diseases Research, Soochow University, Suzhou 215000, China;
- Institute of Neuroscience, Soochow University, Suzhou 215000, China
- The Fourth School of Clinical Medicine, The Affiliated Eye Hospital, Nanjing Medical University, 210029 Nanjing, China
- North District, The Municipal Hospital of Suzhou, Suzhou 215001, China
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7
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Sami N, Kumar V, Islam A, Ali S, Ahmad F, Hassan I. Exploring Missense Mutations in Tyrosine Kinases Implicated with Neurodegeneration. Mol Neurobiol 2016; 54:5085-5106. [PMID: 27544236 DOI: 10.1007/s12035-016-0046-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2016] [Accepted: 08/08/2016] [Indexed: 12/20/2022]
Abstract
Protein kinases are one of the largest families of evolutionarily related proteins and the third most common protein class of human genome. All the protein kinases share the same structural organization. They are made up of an extracellular domain, transmembrane domain and an intra cellular kinase domain. Missense mutations in these kinases have been studied extensively and correlated with various neurological disorders. Individual mutations in the kinase domain affect the functions of protein. The enhanced or reduced expression of protein leads to hyperactivation or inactivation of the signalling pathways, resulting in neurodegeneration. Here, we present extensive analyses of missense mutations in the tyrosine kinase focussing on the neurodegenerative diseases encompassing structure function relationship. This is envisaged to enhance our understanding about the neurodegeneration and possible therapeutic measures.
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Affiliation(s)
- Neha Sami
- Centre for Interdisciplinary Research in Basic Sciences, Jamia Millia Islamia, New Delhi, 110025, India
| | - Vijay Kumar
- Centre for Interdisciplinary Research in Basic Sciences, Jamia Millia Islamia, New Delhi, 110025, India
| | - Asimul Islam
- Centre for Interdisciplinary Research in Basic Sciences, Jamia Millia Islamia, New Delhi, 110025, India
| | - Sher Ali
- Centre for Interdisciplinary Research in Basic Sciences, Jamia Millia Islamia, New Delhi, 110025, India
| | - Faizan Ahmad
- Centre for Interdisciplinary Research in Basic Sciences, Jamia Millia Islamia, New Delhi, 110025, India
| | - Imtaiyaz Hassan
- Centre for Interdisciplinary Research in Basic Sciences, Jamia Millia Islamia, New Delhi, 110025, India.
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8
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Sagi O, Budovsky A, Wolfson M, Fraifeld VE. ShcC proteins: brain aging and beyond. Ageing Res Rev 2015; 19:34-42. [PMID: 25462193 DOI: 10.1016/j.arr.2014.11.002] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2014] [Revised: 11/08/2014] [Accepted: 11/17/2014] [Indexed: 02/02/2023]
Abstract
To date, most studies of Shc family of signaling adaptor proteins have been focused on the near-ubiquitously expressed ShcA, indicating its relevance to age-related diseases and longevity. Although the role of the neuronal ShcC protein is much less investigated, accumulated evidence suggests its importance for neuroprotection against such aging-associated conditions as brain ischemia and oxidative stress. Here, we summarize more than decade of studies on the ShcC expression and function in normal brain, age-related brain pathologies and immune disorders with a focus on the interactions of ShcC with signaling proteins/pathways, and the possible implications of these interactions for changes associated with aging.
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Affiliation(s)
- Orli Sagi
- The Shraga Segal Department of Microbiology, Immunology and Genetics, Center for Multidisciplinary Research on Aging, Ben-Gurion University of the Negev, Beer Sheva 84105, Israel
| | - Arie Budovsky
- The Shraga Segal Department of Microbiology, Immunology and Genetics, Center for Multidisciplinary Research on Aging, Ben-Gurion University of the Negev, Beer Sheva 84105, Israel; Judea Regional Research & Development Center, Carmel 90404, Israel
| | - Marina Wolfson
- The Shraga Segal Department of Microbiology, Immunology and Genetics, Center for Multidisciplinary Research on Aging, Ben-Gurion University of the Negev, Beer Sheva 84105, Israel
| | - Vadim E Fraifeld
- The Shraga Segal Department of Microbiology, Immunology and Genetics, Center for Multidisciplinary Research on Aging, Ben-Gurion University of the Negev, Beer Sheva 84105, Israel.
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9
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Zhou L, Talebian A, Meakin SO. The signaling adapter, FRS2, facilitates neuronal branching in primary cortical neurons via both Grb2- and Shp2-dependent mechanisms. J Mol Neurosci 2014; 55:663-77. [PMID: 25159185 DOI: 10.1007/s12031-014-0406-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2014] [Accepted: 08/15/2014] [Indexed: 12/15/2022]
Abstract
The neurotrophins are a family of closely related growth factors that regulate proliferation and differentiation in the developing and mature nervous systems. Neurotrophins stimulate a family of receptor tyrosine kinases (Trk receptors) and utilize an intracellular docking protein termed fibroblast growth factor (FGF) receptor substrate 2 (FRS2) as a major downstream adapter to activate Ras, phosphatidylinositide 3-kinase (PI3K), and mitogen-activated protein kinase (MAPK) signaling cascades. The goals of this study were twofold: first, to investigate the complexity of neurotrophin-induced FRS2 interactions in primary cortical neurons and to determine which pathway(s) are important in regulating neuronal growth and, second, to determine whether the related signaling adapter, FRS3, stimulates neuron growth comparable to FRS2. We find that neurotrophin treatment of primary cortical neurons stimulates the tyrosine phosphorylation of FRS2 and the subsequent recruitment of Shp2, Grb2, and Gab2. With FRS2 mutants deficient in Grb2 or Shp2 binding, we demonstrate that FRS2 binds Gab1 and Gab2 through Grb2, providing an alternative route to activate PI3 kinase and Shp2. Using recombinant adenoviruses expressing FRS2, we demonstrate that FRS2 overexpression promotes neurite outgrowth and branching in cortical neurons relative to controls. In contrast, overexpression of FRS3 does not stimulate neuronal growth. Moreover, we find that while loss of Shp2, but not Grb2, reduces brain-derived neurotrophic factor (BDNF)-induced MAPK activation, the loss of either pathway impairs neuronal growth. Collectively, these experiments demonstrate that FRS2 functions as an adapter of a multiprotein complex that is activated by the Trk receptors and that the activation of both Grb2- and Shp2-dependent pathways facilitates cortical neuronal growth.
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Affiliation(s)
- Li Zhou
- Laboratory of Neural Signaling, Molecular Medicine Research Group, The Robarts Research Institute, 1151 Richmond St. N, London, Ontario, N6A 5B7, Canada
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10
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Wyatt LA, Filbin MT, Keirstead HS. PTEN inhibition enhances neurite outgrowth in human embryonic stem cell-derived neuronal progenitor cells. J Comp Neurol 2014; 522:2741-55. [PMID: 24610700 DOI: 10.1002/cne.23580] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2013] [Revised: 09/29/2013] [Accepted: 10/07/2013] [Indexed: 12/27/2022]
Abstract
We investigated the role of PTEN (phosphatase and tensin homolog deleted on chromosome 10) during neurite outgrowth of human embryonic stem cell (hESC)-derived neuronal progenitors. PTEN inhibits phosphoinositide 3-kinase (PI3K)/Akt signaling, a common and central outgrowth and survival pathway downstream of neuronal growth factors. It is known that PTEN inhibition, by either polymorphic mutation or gene deletion, can lead to the development of tumorigenesis (Stambolic et al., ; Tamura et al., ). However, temporary inhibition of PTEN, through pharmacological manipulation, could regulate signaling events such as the PI3K/Akt signaling pathway, leading to enhanced recovery of central nervous system (CNS) injury and disease. We demonstrate that pharmacological inhibition of PTEN in hESC-derived neuronal progenitors significantly increased neurite outgrowth in vitro in a dose- and time-dependent manner. Our results indicate that inhibition of PTEN augments neurite outgrowth beyond that of traditional methods such as elevation of intracellular cyclic adenosine monophosphate (cAMP) levels, and depends on upregulation of the PI3K/Akt signaling pathway and its downstream effectors, such as mammalian target of rapamycin (mTOR). PTEN inhibition also rescued neurite outgrowth over an inhibitory substrate in vitro. These findings indicate a remarkable impact on hESC-derived neuronal progenitor plasticity through PTEN inhibition. Overall, these findings identify a novel therapeutic strategy for neurite outgrowth in CNS injury and disease.
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Affiliation(s)
- Lindsey A Wyatt
- Department of Anatomy and Neurobiology, Sue and Bill Gross Stem Cell Research Center, Reeve-Irvine Research Center, School of Medicine, University of California at Irvine, Irvine, California, 92697-4292
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Ceni C, Unsain N, Zeinieh MP, Barker PA. Neurotrophins in the regulation of cellular survival and death. Handb Exp Pharmacol 2014; 220:193-221. [PMID: 24668474 DOI: 10.1007/978-3-642-45106-5_8] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The neurotrophins play crucial roles regulating survival and apoptosis in the developing and injured nervous system. The four neurotrophins exert profound and crucial survival effects on developing peripheral neurons, and their expression and action is intimately tied to successful innervation of peripheral targets. In the central nervous system, they are dispensable for neuronal survival during development but support neuronal survival after lesion or other forms of injury. Neurotrophins also regulate apoptosis of both peripheral and central neurons, and we now recognize that there are regulatory advantages to having the same molecules regulate life and death decisions. This chapter examines the biological contexts in which these events take place and highlights the specific ligands, receptors, and signaling mechanisms that allow them to occur.
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Affiliation(s)
- Claire Ceni
- Centre for Neuronal Survival, Montreal Neurological Institute, McGill University, 3801 University Street, Montreal, QC, Canada, H3A 2B4
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12
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Aasrum M, Ødegård J, Sandnes D, Christoffersen T. The involvement of the docking protein Gab1 in mitogenic signalling induced by EGF and HGF in rat hepatocytes. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2013; 1833:3286-3294. [PMID: 24126105 DOI: 10.1016/j.bbamcr.2013.10.004] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/05/2013] [Revised: 10/07/2013] [Accepted: 10/07/2013] [Indexed: 12/15/2022]
Abstract
Grb2-associated binder (Gab) family proteins are docking molecules that can interact with receptor tyrosine kinases (RTKs) and cytokine receptors and bind several downstream signalling proteins. Studies in several cell types have shown that Gab1 may have a role in signalling mediated by the two RTKs epidermal growth factor (EGF) receptor (EGFR) and Met, the receptor for hepatocyte growth factor (HGF), but the involvement of Gab1 in EGFR and Met signalling has not been directly compared in the same cell. We have studied mechanisms of activation and role in mitogenic signalling of Gab1 in response to EGF and HGF in cultured rat hepatocytes. Gab1, but not Gab2, was expressed in the hepatocytes and was phosphorylated upon stimulation with EGF or HGF. Depletion of Gab1, using siRNA, decreased the ERK and Akt activation, cyclin D1 expression, and DNA synthesis in response to both EGF and HGF. Studies of mechanisms of recruitment to the receptors showed that HGF induced co-precipitation of Gab1 and Met while EGF induced binding of Gab1 to Grb2 but not to EGFR. Gab1 activation in response to both EGF and HGF was dependent on PI3K. While EGF activated Gab1 and Shc equally, within the same concentration range, HGF very potently and almost exclusively activated Gab1, having only a minimal effect on Shc. Collectively, our results strongly suggest that although Gab1 interacts differently with EGFR and Met, it is involved in mitogenic signalling mediated by both these growth factor receptors in hepatocytes.
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Affiliation(s)
- Monica Aasrum
- Department of Pharmacology, Institute of Clinical Medicine, University of Oslo and Oslo University Hospital, P.O. Box 1057, Blindern, 0316 Oslo, Norway.
| | - John Ødegård
- Department of Pharmacology, Institute of Clinical Medicine, University of Oslo and Oslo University Hospital, P.O. Box 1057, Blindern, 0316 Oslo, Norway
| | - Dagny Sandnes
- Department of Pharmacology, Institute of Clinical Medicine, University of Oslo and Oslo University Hospital, P.O. Box 1057, Blindern, 0316 Oslo, Norway
| | - Thoralf Christoffersen
- Department of Pharmacology, Institute of Clinical Medicine, University of Oslo and Oslo University Hospital, P.O. Box 1057, Blindern, 0316 Oslo, Norway
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13
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Rajala A, Dilly AK, Rajala RV. Protein tyrosine phosphatase-1B regulates the tyrosine phosphorylation of the adapter Grb2-associated binder 1 (Gab1) in the retina. Cell Commun Signal 2013; 11:20. [PMID: 23521888 PMCID: PMC3637500 DOI: 10.1186/1478-811x-11-20] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2013] [Accepted: 03/19/2013] [Indexed: 01/31/2023] Open
Abstract
BACKGROUND Gab1 (Grb2-associated binder 1) is a key coordinator that belongs to the insulin receptor substrate-1 like family of adaptor molecules and is tyrosine phosphorylated in response to various growth factors, cytokines, and numerous other molecules. Tyrosine phosphorylated Gab1 is able to recruit a number of signaling effectors including PI3K, SHP2 and PLC-γ. In this study, we characterized the localization and regulation of tyrosine phosphorylation of Gab1 in the retina. RESULTS Our immuno localization studies suggest that Gab1 is expressed in rod photoreceptor inner segments. We found that hydrogen peroxide activates the tyrosine phosphorylation of Gab1 ex vivo and hydrogen peroxide has been shown to inhibit the protein tyrosine phosphatase PTP1B activity. We found a stable association between the D181A substrate trap mutant of PTP1B and Gab1. Our studies suggest that PTP1B interacts with Gab1 through Tyrosine 83 and this residue may be the major PTP1B target residue on Gab1. We also found that Gab1 undergoes a light-dependent tyrosine phosphorylation and PTP1B regulates the phosphorylation state of Gab1. Consistent with these observations, we found an enhanced Gab1 tyrosine phosphorylation in PTP1B deficient mice and also in retinas treated ex vivo with a PTP1B specific allosteric inhibitor. CONCLUSIONS Our laboratory has previously reported that retinas deficient of PTP1B are resistant to light damage compared to wild type mice. Since Gab1 is negatively regulated by PTP1B, a part of the retinal neuroprotective effect we have observed previously in PTP1B deficient mice could be contributed by Gab1 as well. In summary, our data suggest that PTP1B regulates the phosphorylation state of retinal Gab1 in vivo.
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Affiliation(s)
- Ammaji Rajala
- Departments of Ophthalmology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, 73104, USA.
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Felici A, Giubellino A, Bottaro DP. Gab1 mediates hepatocyte growth factor-stimulated mitogenicity and morphogenesis in multipotent myeloid cells. J Cell Biochem 2011; 111:310-21. [PMID: 20506405 DOI: 10.1002/jcb.22695] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Hepatocyte growth factor (HGF)-stimulated mitogenesis, motogenesis and morphogenesis in various cell types begins with activation of the Met receptor tyrosine kinase and the recruitment of intracellular adaptors and kinase substrates. The adapter protein Gab1 is a critical effector and substrate of activated Met, mediating morphogenesis, among other activities, in epithelial cells. To define its role downstream of Met in hematopoietic cells, Gab1 was expressed in the HGF-responsive, Gab1-negative murine myeloid cell line 32D. Interestingly, the adhesion and motility of Gab1-expressing cells were significantly greater than parental cells, independent of growth factor treatment. Downstream of activated Met, Gab1 expression was specifically associated with rapid Shp-2 recruitment and activation, increased mitogenic potency, suppression of GATA-1 expression and concomitant upregulation of GATA-2 transcription. In addition to enhanced proliferation, continuous culture of Gab1-expressing 32D cells in HGF resulted in cell attachment, filopodia extension and phenotypic changes suggestive of monocytic differentiation. Our results suggest that in myeloid cells, Gab1 is likely to enhance HGF mitogenicity by coupling Met to Shp-2 and GATA-2 expression, thereby potentially contributing to normal myeloid differentiation as well as oncogenic transformation.
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Affiliation(s)
- Angelina Felici
- Urologic Oncology Branch, Center for Cancer Research, National Cancer Institute, National, Institutes of Health, Bethesda, Maryland 20892-1501, USA
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15
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Abstract
In vivo regeneration of peripheral neurons is constrained and rarely complete, and unfortunately patients with major nerve trunk transections experience only limited recovery. Intracellular inhibition of neuronal growth signals may be among these constraints. In this work, we investigated the role of PTEN (phosphatase and tensin homolog deleted on chromosome 10) during regeneration of peripheral neurons in adult Sprague Dawley rats. PTEN inhibits phosphoinositide 3-kinase (PI3-K)/Akt signaling, a common and central outgrowth and survival pathway downstream of neuronal growth factors. While PI3-K and Akt outgrowth signals were expressed and activated within adult peripheral neurons during regeneration, PTEN was similarly expressed and poised to inhibit their support. PTEN was expressed in neuron perikaryal cytoplasm, nuclei, regenerating axons, and Schwann cells. Adult sensory neurons in vitro responded to both graded pharmacological inhibition of PTEN and its mRNA knockdown using siRNA. Both approaches were associated with robust rises in the plasticity of neurite outgrowth that were independent of the mTOR (mammalian target of rapamycin) pathway. Importantly, this accelerated outgrowth was in addition to the increased outgrowth generated in neurons that had undergone a preconditioning lesion. Moreover, following severe nerve transection injuries, local pharmacological inhibition of PTEN or siRNA knockdown of PTEN at the injury site accelerated axon outgrowth in vivo. The findings indicated a remarkable impact on peripheral neuron plasticity through PTEN inhibition, even within a complex regenerative milieu. Overall, these findings identify a novel route to propagate intrinsic regeneration pathways within axons to benefit nerve repair.
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Dijkmans TF, van Hooijdonk LWA, Schouten TG, Kamphorst JT, Vellinga ACA, Meerman JHN, Fitzsimons CP, de Kloet ER, Vreugdenhil E. Temporal and functional dynamics of the transcriptome during nerve growth factor-induced differentiation. J Neurochem 2010; 105:2388-403. [PMID: 18346208 DOI: 10.1111/j.1471-4159.2008.05338.x] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The rat pheochromocytoma cell line (PC12) is an extensively used model to study neuronal differentiation. The initial signaling cascades triggered by nerve growth factor (NGF) stimulation have been subject to thorough investigation and are well characterized. However, knowledge of temporal transcriptomal regulation during NGF-induced differentiation of PC12 cells remains far from complete. We performed a microarray study that characterized temporal and functional changes of the transcriptome during 4 subsequent days of differentiation of Neuroscreen-1 PC12 cells. By analyzing the transcription profiles of 1595 NGF-regulated genes, we show a large diversity of transcriptional regulation in time. Also, we quantitatively identified 26 out of 243 predefined biological process and 30 out of 255 predefined molecular function classes that are specifically regulated by NGF. Combining the temporal and functional transcriptomal data revealed that NGF selectively exerts a temporally coordinated regulation of genes implicated in protein biosynthesis, intracellular signaling, cell structure, chromatin packaging and remodeling, intracellular protein traffic, mRNA transcription, and cell cycle. We will discuss how NGF-induced changes may modulate the transcriptional response to NGF itself during differentiation.
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Affiliation(s)
- Thomas F Dijkmans
- Division of Medical Pharmacology, Leiden/Amsterdam Center for Drug Research and Leiden University Medical Center, Leiden, The Netherlands.
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17
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Weng T, Mao F, Wang Y, Sun Q, Li R, Yang G, Zhang X, Luo J, Feng GS, Yang X. Osteoblastic molecular scaffold Gab1 is required for maintaining bone homeostasis. J Cell Sci 2010; 123:682-9. [PMID: 20124419 DOI: 10.1242/jcs.058396] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
The Grb2-associated binder 1 (Gab1), which serves as a scaffolding adaptor protein, plays a crucial role in transmitting key signals that control cell growth, differentiation and function from multiple receptors. However, its biological role in osteoblast activity and postnatal bone metabolism remains unclear. To elucidate the in vivo function of Gab1 in postnatal bone remodeling, we generated osteoblast-specific Gab1 knockout mice. Disruption of Gab1 expression in osteoblasts led to decreased trabecular bone mass with a reduced bone formation rate and a decreased bone resorption. Bones from Gab1 mutants also exhibited inferior mechanical properties. Moreover, primary osteoblasts from Gab1 mutant mice demonstrated markedly suppressed osteoblast mineralization, increased susceptibility to apoptosis and decreased expression of receptor activator of NF-kappaB ligand (RANKL). Activation of serine-threonine Akt kinase and extracellular signal-regulated kinase in response to insulin and insulin-like growth factor 1 was attenuated in Gab1 mutant osteoblasts. Our results show that Gab1-mediated signals in osteoblasts are crucial for normal postnatal bone homeostasis.
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Affiliation(s)
- Tujun Weng
- State Key Laboratory of Proteomics, Genetic Laboratory of Development and Disease, Institute of Biotechnology, Beijing 100071, PR China
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18
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Chung J, Kubota H, Ozaki YI, Uda S, Kuroda S. Timing-dependent actions of NGF required for cell differentiation. PLoS One 2010; 5:e9011. [PMID: 20126402 PMCID: PMC2814856 DOI: 10.1371/journal.pone.0009011] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2009] [Accepted: 01/06/2010] [Indexed: 01/25/2023] Open
Abstract
Background Continuous NGF stimulation induces PC12 cell differentiation. However, why continuous NGF stimulation is required for differentiation is unclear. In this study, we investigated the underlying mechanisms of the timing-dependent requirement of NGF action for cell differentiation. Methodology/Principal Findings To address the timing-dependency of the NGF action, we performed a discontinuous stimulation assay consisting of a first transient stimulation followed by an interval and then a second sustained stimulation and quantified the neurite extension level. Consequently, we observed a timing-dependent action of NGF on cell differentiation, and discontinuous NGF stimulation similarly induced differentiation. The first stimulation did not induce neurite extension, whereas the second stimulation induced fast neurite extension; therefore, the first stimulation is likely required as a prerequisite condition. These observations indicate that the action of NGF can be divided into two processes: an initial stimulation-driven latent process and a second stimulation-driven extension process. The latent process appears to require the activities of ERK and transcription, but not PI3K, whereas the extension-process requires the activities of ERK and PI3K, but not transcription. We also found that during the first stimulation, the activity of NGF can be replaced by PACAP, but not by insulin, EGF, bFGF or forskolin; during the second stimulation, however, the activity of NGF cannot be replaced by any of these stimulants. These findings allowed us to identify potential genes specifically involved in the latent process, rather than in other processes, using a microarray. Conclusions/Significance These results demonstrate that NGF induces the differentiation of PC12 cells via mechanically distinct processes: an ERK-driven and transcription-dependent latent process, and an ERK- and PI3K-driven and transcription-independent extension process.
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Affiliation(s)
- Jaehoon Chung
- Department of Biophysics and Biochemistry, Graduate School of Science, CREST, Japan Science and Technology Agency, University of Tokyo, Tokyo, Japan
| | - Hiroyuki Kubota
- Department of Biophysics and Biochemistry, Graduate School of Science, CREST, Japan Science and Technology Agency, University of Tokyo, Tokyo, Japan
| | - Yu-ichi Ozaki
- Department of Biophysics and Biochemistry, Graduate School of Science, CREST, Japan Science and Technology Agency, University of Tokyo, Tokyo, Japan
| | - Shinsuke Uda
- Department of Biophysics and Biochemistry, Graduate School of Science, CREST, Japan Science and Technology Agency, University of Tokyo, Tokyo, Japan
| | - Shinya Kuroda
- Department of Biophysics and Biochemistry, Graduate School of Science, CREST, Japan Science and Technology Agency, University of Tokyo, Tokyo, Japan
- * E-mail:
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Wöhrle FU, Daly RJ, Brummer T. Function, regulation and pathological roles of the Gab/DOS docking proteins. Cell Commun Signal 2009; 7:22. [PMID: 19737390 PMCID: PMC2747914 DOI: 10.1186/1478-811x-7-22] [Citation(s) in RCA: 128] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2009] [Accepted: 09/08/2009] [Indexed: 01/13/2023] Open
Abstract
Since their discovery a little more than a decade ago, the docking proteins of the Gab/DOS family have emerged as important signalling elements in metazoans. Gab/DOS proteins integrate and amplify signals from a wide variety of sources including growth factor, cytokine and antigen receptors as well as cell adhesion molecules. They also contribute to signal diversification by channelling the information from activated receptors into signalling pathways with distinct biological functions. Recent approaches in protein biochemistry and systems biology have revealed that Gab proteins are subject to complex regulation by feed-forward and feedback phosphorylation events as well as protein-protein interactions. Thus, Gab/DOS docking proteins are at the centre of entire signalling subsystems and fulfil an important if not essential role in many physiological processes. Furthermore, aberrant signalling by Gab proteins has been increasingly linked to human diseases from various forms of neoplasia to Alzheimer's disease. In this review, we provide a detailed overview of the structure, effector functions, regulation and evolution of the Gab/DOS family. We also summarize recent findings implicating Gab proteins, in particular the Gab2 isoform, in leukaemia, solid tumours and other human diseases.
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Affiliation(s)
- Franziska U Wöhrle
- Centre for Biological Systems Analysis (ZBSA), Albert-Ludwigs-University of Freiburg, Germany.
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20
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Caron C, Spring K, Laramée M, Chabot C, Cloutier M, Gu H, Royal I. Non-redundant roles of the Gab1 and Gab2 scaffolding adapters in VEGF-mediated signalling, migration, and survival of endothelial cells. Cell Signal 2009; 21:943-53. [PMID: 19233262 DOI: 10.1016/j.cellsig.2009.02.004] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2008] [Revised: 02/02/2009] [Accepted: 02/10/2009] [Indexed: 01/07/2023]
Abstract
Gab1 was previously described as a positive modulator of Akt, Src, ERK1/2, endothelial cell migration, and capillary formation in response to vascular endothelial growth factor (VEGF). However, its involvement in endothelial cell survival, as well as the potential contribution of the other family member Gab2 to signalling and biological responses remained unknown. Here, we show that Gab2 is tyrosine phosphorylated in a Grb2-dependent manner downstream of activated VEGF receptor-2 (VEGFR2), and that it associates with signalling proteins including PI3K and SHP2, but apparently not with the receptor. Similarly to Gab1, over-expression of Gab2 induces endothelial cell migration in response to VEGF, whereas its depletion using siRNAs results in its reduction. Importantly, depletion of both Gab1 and Gab2 leads to an even greater inhibition of VEGF-induced cell migration. However, contrary to what has been reported for Gab1, the silencing of Gab2 results in increased Src, Akt and ERK1/2 activation, slightly reduced p38 phosphorylation, and up-regulation of Gab1 protein levels. Accordingly, re-expression of Gab2 in Gab2-/- fibroblasts leads to opposite results, suggesting that the modulation of both Gab2 and Gab1 expression in these conditions might contribute to the impaired signalling observed. Consistent with their opposite roles on Akt, the depletion of Gab1, but not of Gab2, results in reduced FOXO1 phosphorylation and VEGF-mediated endothelial cell survival. Mutation of VEGFR2 Y801 and Y1214, which abrogates the phosphorylation of Gab1, also correlates with inhibition of Akt. Altogether, these results underscore the non-redundant and essential roles of Gab1 and Gab2 in endothelial cells, and suggest major contributions of these proteins during in vivo angiogenesis.
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Affiliation(s)
- Christine Caron
- Centre de recherche du Centre Hospitalier de l'Université de Montréal, 1560 rue Sherbrooke est, Montréal, Québec, Canada.
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Abstract
In the diabetic eye, the increased accumulation of sorbitol in the retina has been implicated in the pathogenesis of diabetic retinopathy (DR). Neurodegeneration is an important component of DR as demonstrated by increased neural apoptosis in the retina during experimental and human diabetes. Insulin receptor (IR) activation has been shown to rescue retinal neurons from apoptosis through a phosphoinositide 3-kinase and protein kinase B (Akt) survival cascade. In this study, we examined the IR signaling in sorbitol-induced hyperosmotic stressed retinas.
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22
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Developmental axon pruning mediated by BDNF-p75NTR-dependent axon degeneration. Nat Neurosci 2008; 11:649-58. [PMID: 18382462 DOI: 10.1038/nn.2114] [Citation(s) in RCA: 182] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2008] [Accepted: 03/25/2008] [Indexed: 02/04/2023]
Abstract
The mechanisms that regulate the pruning of mammalian axons are just now being elucidated. Here, we describe a mechanism by which, during developmental sympathetic axon competition, winning axons secrete brain-derived neurotrophic factor (BDNF) in an activity-dependent fashion, which binds to the p75 neurotrophin receptor (p75NTR) on losing axons to cause their degeneration and, ultimately, axon pruning. Specifically, we found that pruning of rat and mouse sympathetic axons that project to the eye requires both activity-dependent BDNF and p75NTR. p75NTR and BDNF are also essential for activity-dependent axon pruning in culture, where they mediate pruning by directly causing axon degeneration. p75NTR, which is enriched in losing axons, causes axonal degeneration by suppressing TrkA-mediated signaling that is essential for axonal maintenance. These data provide a mechanism that explains how active axons can eliminate less-active, competing axons during developmental pruning by directly promoting p75NTR-mediated axonal degeneration.
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Hayakawa-Yano Y, Nishida K, Fukami S, Gotoh Y, Hirano T, Nakagawa T, Shimazaki T, Okano H. Epidermal growth factor signaling mediated by grb2 associated binder1 is required for the spatiotemporally regulated proliferation of olig2-expressing progenitors in the embryonic spinal cord. Stem Cells 2007; 25:1410-22. [PMID: 17332510 DOI: 10.1634/stemcells.2006-0584] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Gab1 (Grb2 associated binder1) has been identified as an adaptor molecule downstream of many growth factors, including epidermal growth factor (EGF), fibroblast growth factor, and platelet-derived growth factor, which have been shown to play crucial roles as mitotic signals for a variety of neural progenitor cells, including stem cells, both in vitro and in vivo. Here, we show that Gab1 deficiency results in a reduction in the number of Olig2-positive (Olig2(+)) progenitor cells in the developing mouse spinal cord after embryonic day 12.5 (E12.5), when gliogenesis starts in the pMN domain where the EGF receptor (EGFR) is expressed predominantly. Our in vitro analysis further revealed that Gab1 is essential for EGF-dependent proliferation of Olig2(+) progenitor cells derived from the E12.5 ventral and E14.5 dorsal but not ventral spinal cord, whereas Gab1 is always required for the activation of Akt1 but not of ERK1/2. Moreover, we found that the action of the Gab1/Akt pathway is context-dependent, since constitutively active Akt1 could rescue the proliferation defect only in the E12.5 spinal cord of the Gab1-deficient mouse in vitro. Finally, we demonstrated that EGFR-deficient mice and Gab1-deficient mice showed a similar reduction in the number of Olig2(+) progenitor cells in the developing spinal cord. These findings indicate that EGFR-mediated signaling through Gab1/Akt contributes to the sufficient expansion of Olig2(+) progenitor cells in a spatiotemporally regulated manner, which represents the origin of glial cells in the developing spinal cord. Disclosure of potential conflicts of interest is found at the end of this article.
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Affiliation(s)
- Yoshika Hayakawa-Yano
- Department of Physiology, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ku, Tokyo 160-8582, Japan
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Gandhi AK, Kang J, Naziruddin S, Parton A, Schafer PH, Stirling DI. Lenalidomide inhibits proliferation of Namalwa CSN.70 cells and interferes with Gab1 phosphorylation and adaptor protein complex assembly. Leuk Res 2006; 30:849-58. [PMID: 16494942 DOI: 10.1016/j.leukres.2006.01.010] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2005] [Revised: 01/17/2006] [Accepted: 01/18/2006] [Indexed: 01/01/2023]
Abstract
Lenalidomide (Revlimid, CC-5013) belongs to a line of compounds known as immunomodulatory drugs (IMiDs) that are under clinical investigation in hematopoietic and solid tumor cancers. Lenalidomide efficacy has been reported in clinical trials of multiple myeloma and myelodysplastic syndromes (MDS), particularly in MDS patients with a del 5q cytogenetic abnormality, with or without other cytogenetic abnormalities. Here we report that lenalidomide inhibits proliferation of chromosome 5 deleted hematopoietic tumor cell lines in vitro, whether from the B cell, T cell, or myeloid lineage. There was diversity in the responses of the various cell lines to lenalidomide, with one undergoing cell cycle arrest, and others undergoing apoptosis. In the most lenalidomide-sensitive chromosome 5 deleted cell line, Namalwa CSN.70, the compound induced G0/G1 cell cycle arrest, inhibited Akt and Gab1 phosphorylation, and inhibited the ability of Gab1 to associate with a receptor tyrosine kinase. Lenalidomide also enhanced AP-1 transcriptional activity in Namalwa, but not in the other cell lines tested. These studies provide evidence for the mechanism of action of lenalidomide in chromosome 5 deleted hematopoietic tumors in vitro, and may provide a better understanding of the drug's activity in clinical applications.
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Affiliation(s)
- Anita K Gandhi
- Celgene Corporation, 86 Morris Avenue, Summit, NJ 07901, United States.
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25
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Kalkman HO. The role of the phosphatidylinositide 3-kinase–protein kinase B pathway in schizophrenia. Pharmacol Ther 2006; 110:117-34. [PMID: 16434104 DOI: 10.1016/j.pharmthera.2005.10.014] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2005] [Accepted: 10/26/2005] [Indexed: 01/05/2023]
Abstract
Neuroanatomical studies of brains from schizophrenic patients report evidence for neuronal dystrophy, while in genetic studies in schizophrenia there is evidence for mutations in growth factors and the downstream enzymes phosphatidylinositide 3-kinase (PI3K) and protein kinase B (PKB). Since the PI3K-PKB pathway is involved in cellular growth and proliferation, reduced activity of this cascade in schizophrenia could at least partly explain the neuronal dystrophy. Risk factors for schizophrenia, such as corticosteroids and cannabis, suppress the activity of the PI3K-PKB pathway. Conversely, estrogen and vitamin D, 2 factors with a moderate protective activity in schizophrenia, electroconvulsive shock therapy, and chronic treatment with antipsychotic compounds stimulate the pathway. Reduced activity of the PI3K-PKB pathway makes the brain more susceptible to virus infections, anoxia, and obstetric complications (recognized risk factors for schizophrenia), whereas a diminution of growth factor levels towards the end of puberty could contribute to an increase in schizophrenia symptoms observed around that time. On the other hand, constitutive (over)activation of the PI3K-PKB pathway increases cancer risk. Consequently, the presumed hypoactivity of the PI3K-PKB cascade might provide a partial explanation for the remarkable epidemiological finding of a reduced cancer rate in schizophrenic patients. Recognition of the role of a dysfunctional PI3K-PKB pathway in schizophrenia might help in the discovery of hitherto undetected causative gene mutations and could also lead to novel therapeutic approaches. However, a major challenge that remains to be solved is how the PI3K-PKB pathway can be activated without increasing the risk of cancer.
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Affiliation(s)
- Hans O Kalkman
- Neuroscience Research, Novartis Institutes of Biomedical Research Basel, Building WSJ-360.4.05, Novartis Pharma AG, CH4002 Basel, Switzerland.
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Kiyama A, Isojima Y, Nagai K. Role of Per1-interacting protein of the suprachiasmatic nucleus in NGF mediated neuronal survival. Biochem Biophys Res Commun 2006; 339:514-9. [PMID: 16298334 DOI: 10.1016/j.bbrc.2005.11.036] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2005] [Accepted: 11/04/2005] [Indexed: 11/25/2022]
Abstract
We previously identified Per1-interacting protein of the suprachiasmatic nucleus (PIPS) in rats. To reveal its role, its tissue distribution was examined by immunoblotting. PIPS-like immunoreactive substance (PIPSLS) was observed in the brain, adrenal gland, and PC12 cells. Since PIPS, which has no nuclear localization signal (NLS), is translocated into nuclei of COS-7 cells in the presence of mPer1, the effect of NGF on nuclear localization of PIPS was examined using PC12 cells. NGF caused nuclear translocation of either PIPSLS or GFP-PIPS. NGF mediated nuclear translocation of PIPSLS was blocked by K252a, a TrkA-inhibitor, or wortmannin, a PI3K-inhibitor. Gab1, which is implicated in TrkA signaling and has NLS, co-immunoprecipitated with PIPSLS from PC12 cells using an anti-PIPS antibody. Inhibition of PIPS expression by RNAi increased levels of apoptosis in PC12 cells. These findings suggest that nuclear translocation of PIPS is involved in NGF mediated neuronal survival via TrkA, PI3K, and Gab1 signaling pathway.
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Affiliation(s)
- Atsuko Kiyama
- Institute for Protein Research, Osaka University, 3-2 Yamada-Oka, Suita, Osaka 565-0871, Japan.
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27
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Scheidenhelm DK, Cresswell J, Haipek CA, Fleming TP, Mercer RW, Gutmann DH. Akt-dependent cell size regulation by the adhesion molecule on glia occurs independently of phosphatidylinositol 3-kinase and Rheb signaling. Mol Cell Biol 2005; 25:3151-62. [PMID: 15798201 PMCID: PMC1069598 DOI: 10.1128/mcb.25.8.3151-3162.2005] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2004] [Revised: 10/12/2004] [Accepted: 01/06/2005] [Indexed: 12/13/2022] Open
Abstract
The role of cell adhesion molecules in mediating interactions with neighboring cells and the extracellular matrix has long been appreciated. More recently, these molecules have been shown to modulate intracellular signal transduction cascades critical for cell growth and proliferation. Expression of adhesion molecule on glia (AMOG) is downregulated in human and mouse gliomas, suggesting that AMOG may be important for growth regulation in the brain. In this report, we examined the role of AMOG expression on cell growth and intracellular signal transduction. We show that AMOG does not negatively regulate cell growth in vitro or in vivo. Instead, expression of AMOG in AMOG-deficient cells results in a dramatic increase in cell size associated with protein kinase B/Akt hyperactivation, which occurs independent of phosphatidylinositol 3-kinase activation. AMOG-mediated Akt phosphorylation specifically activates the mTOR/p70S6 kinase pathway previously implicated in cell size regulation, but it does not depend on tuberous sclerosis complex/Ras homolog enriched in brain (Rheb) signaling. These data support a novel role for a glial adhesion molecule in cell size regulation through selective activation of the Akt/mTOR/S6K signal transduction pathway.
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Affiliation(s)
- Danielle K Scheidenhelm
- Department of Neurology, Washington University School of Medicine, Box 8111, 660 S. Euclid Ave., St. Louis, MO 63110, USA
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28
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Holgado-Madruga M, Wong AJ. Role of the Grb2-associated binder 1/SHP-2 interaction in cell growth and transformation. Cancer Res 2004; 64:2007-15. [PMID: 15026337 DOI: 10.1158/0008-5472.can-03-2886] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Grb2-associated binder 1 (Gab1) is a docking protein that is tyrosine phosphorylated following the activation of multiple cytokine receptors and receptor tyrosine kinases. Its function then is to recruit and activate multiple signaling molecules. In our previous work, we showed that Gab1 enhances cell growth and induces the transformed phenotype in NIH3T3 cells downstream of the epidermal growth factor (EGF) receptor. In this report, we analyze how it produces these effects. Because SHP-2 is the major binding partner of Gab1, we mutated its binding site in the Gab1 cDNA (Gab1/DeltaSHP-2). This construct was stably overexpressed in NIH3T3 cells (3T3-Gab1/DeltaSHP-2) and in the wild-type Gab1 cDNA (3T3-Gab1) or an empty expression vector (3T3-CTR). Our findings show that after EGF stimulation, Gab1/DeltaSHP-2 has a higher level of tyrosine phosphorylation at early time points than Gab1. Gab1/DeltaSHP-2 recruits more phosphatidylinositol 3'-kinase than Gab1 after EGF triggering, which accounts for a higher and more sustained AKT activation in 3T3-Gab1/DeltaSHP-2 cells relative to 3T3-Gab1 fibroblasts. Moreover, 3T3-Gab1/DeltaSHP-2 cells demonstrate a higher level of extracellular-regulated kinase 1 activation at early time points of EGF stimulation. However, there was an unexpected decrease in c-fos promoter induction in 3T3-Gab1/DeltaSHP-2 cells when compared with 3T3-Gab1 cells. Additionally, the 3T3-Gab1/DeltaSHP-2 cells show a reversion of the transformed phenotype, including fewer morphologic changes, an increase in stress fiber cytoskeletal organization, and a decrease in cell proliferation and anchorage independent growth. These results reveal that the Gab1/SHP-2 interaction is essential for cell growth and transformation but that this must occur through a novel pathway that is independent of extracellular-regulated kinase or AKT. On the basis of its role in growth and transformation, the Gab1/SHP-2 interaction may become an attractive target for the pharmacologic intervention of malignant cell growth.
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Affiliation(s)
- Marina Holgado-Madruga
- Department of Microbiology and Immunology, The Kimmel Cancer Institute, Thomas Jefferson University, 233 South 10th Street, 1002 BLSB, Philadelphia, PA 19107, USA.
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Nishida K, Hirano T. The role of Gab family scaffolding adapter proteins in the signal transduction of cytokine and growth factor receptors. Cancer Sci 2003; 94:1029-33. [PMID: 14662016 PMCID: PMC11160109 DOI: 10.1111/j.1349-7006.2003.tb01396.x] [Citation(s) in RCA: 152] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2003] [Accepted: 10/20/2003] [Indexed: 11/30/2022] Open
Abstract
The Grb2-associated binder (Gab) family adapter proteins are scaffolding adapter molecules that display sequence similarity with Drosophila DOS (daughter of sevenless), which is a substrate for the protein tyrosine phosphatase Corkscrew. Gab proteins contain a pleckstrin homology (PH) domain and binding sites for SH2 and SH3 domains. A number of studies in multiple systems have implicated Gab in signaling via many different types of receptors, such as growth factor, cytokine, and antigen receptors, and via oncoproteins. Recent studies of Gab1 and Gab2 knockout mice have clearly indicated an important role for Gabs in vivo. Gab1-deficient mice die as embryos with multiple defects in placental, heart, skin, and muscle development. Gab2-deficient mice are viable, but have a defect in the mast cell lineages and in allergic reactions. Given the apparently central role played by Gab signaling via many receptors, delineating the precise mechanism(s) of Gab-mediated signaling is critical to understanding how cytokines, growth factors, and oncoproteins mediate a variety of biological activities: cell growth, differentiation, survival and malignant transformation.
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Affiliation(s)
- Keigo Nishida
- Department of Molecular Oncology (C7), Graduate School of Frontier Biosciences, Osaka University, 2-2 Yamada-oka, Suita, Osaka 565-0871
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30
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Semaphorin 3F antagonizes neurotrophin-induced phosphatidylinositol 3-kinase and mitogen-activated protein kinase kinase signaling: a mechanism for growth cone collapse. J Neurosci 2003. [PMID: 12930799 DOI: 10.1523/jneurosci.23-20-07602.2003] [Citation(s) in RCA: 84] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Peripheral nerve growth is regulated by the coordinated action of numerous external stimuli, including positively acting neurotrophin-derived growth cues and restrictive semaphorin cues. Here, we show that Semaphorin 3F (Sema 3F) can antagonize nerve growth factor (NGF)-stimulated TrkA (tyrosine receptor kinase A) signaling in sympathetic neurons, thereby apparently contributing to growth cone collapse. Sema 3F suppressed NGF-induced activation of the phosphatidylinositol 3 (PI3)-kinase-Akt and MEK (mitogen-activated protein kinase kinase)-ERK (extracellular signal-regulated kinase) pathways, both of which we show to be required to maintain growth cone structure. Sema 3F-induced growth cone collapse was partially reversed by sustained activation of the PI3-kinase and MEK pathways, which was achieved by overexpression of the Gab-1 (growth-associated binder 1) docking protein. These data indicate that a novel mechanism used by Sema 3F to collapse growth cones in sympathetic neurons is to dampen neurotrophin signaling, providing an intracellular mechanism for cross talk between positive and negative axon growth cues.
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31
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Zhao C, Ma H, Bossy-Wetzel E, Lipton SA, Zhang Z, Feng GS. GC-GAP, a Rho family GTPase-activating protein that interacts with signaling adapters Gab1 and Gab2. J Biol Chem 2003; 278:34641-53. [PMID: 12819203 DOI: 10.1074/jbc.m304594200] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Gab1 and Gab2 are scaffolding proteins acting downstream of cell surface receptors and interact with a variety of cytoplasmic signaling proteins such as Grb2, Shp-2, phosphatidylinositol 3-kinase, Shc, and Crk. To identify new binding partners for GAB proteins and better understand their functions, we performed a yeast two-hybrid screening with hGab2-(120-587) as bait. This work led to identification of a novel GTPase-activating protein (GAP) for Rho family GTPases. The GAP domain shows high similarity to the recently cloned CdGAP and displays activity toward RhoA, Rac1, and Cdc42 in vitro. The protein was named GC-GAP for its ability to interact with GAB proteins and its activity toward Rac and Cdc42. GC-GAP is predominantly expressed in the brain with low levels detected in other tissues. Antibodies directed against GC-GAP recognized a protein of approximately 200 kDa. Expression of GC-GAP in 293T cells led to a reduction in active Rac1 and Cdc42 levels but not RhoA. Suppression of GC-GAP expression by siRNA inhibited proliferation of C6 astroglioma cells. In addition, GC-GAP contains several classic proline-rich motifs, and it interacts with the first SH3 domain of Crk and full-length Nck in vitro. We propose that Gab1 and Gab2 in cooperation with other adapter molecules might regulate the cellular localization of GC-GAP under specific stimuli, acting to regulate precisely Rac and Cdc42 activities. Given that GC-GAP is specifically expressed in the nervous system and that it is localized to the dendritic processes of cultured neurons, GC-GAP may play a role in dendritic morphogenesis and also possibly in neural/glial cell proliferation.
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MESH Headings
- Adaptor Proteins, Signal Transducing
- Amino Acid Motifs
- Amino Acid Sequence
- Animals
- Blotting, Northern
- Blotting, Western
- Brain/metabolism
- Cell Differentiation
- Cell Division
- Cell Line
- DNA/metabolism
- DNA, Complementary/metabolism
- Dendrites/metabolism
- GTPase-Activating Proteins/chemistry
- GTPase-Activating Proteins/metabolism
- GTPase-Activating Proteins/physiology
- HeLa Cells
- Humans
- In Situ Hybridization
- Microscopy, Fluorescence
- Models, Genetic
- Molecular Sequence Data
- Phosphoproteins/metabolism
- Precipitin Tests
- Proline/chemistry
- Protein Binding
- Protein Structure, Tertiary
- RNA, Small Interfering/metabolism
- Sequence Homology, Amino Acid
- Signal Transduction
- Transfection
- Tumor Cells, Cultured
- Two-Hybrid System Techniques
- rac1 GTP-Binding Protein/metabolism
- rhoA GTP-Binding Protein/metabolism
- src Homology Domains
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Affiliation(s)
- Chunmei Zhao
- Burnham Institute, La Jolla, California 92037, USA
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32
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Jones DM, Tucker BA, Rahimtula M, Mearow KM. The synergistic effects of NGF and IGF-1 on neurite growth in adult sensory neurons: convergence on the PI 3-kinase signaling pathway. J Neurochem 2003; 86:1116-28. [PMID: 12911620 DOI: 10.1046/j.1471-4159.2003.01925.x] [Citation(s) in RCA: 144] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Nerve growth factor (NGF) and insulin-like growth factor-1 (IGF-1) play an important role in promoting axonal growth from dorsal root ganglion (DRG) neurons. Adult DRG neurons exhibit neurotrophin-independent survival, providing an excellent system with which to study trophic factor effects on neurite growth in the absence of significant survival effects. Using young adult rat DRG neurons we have demonstrated a synergistic effect of NGF plus IGF (N + I), compared with either factor alone, in promoting neurite growth. Not only does the presence of NGF and IGF-1 enhance neurite initiation, it also significantly augments the extent of neurite branching and elongation. We have also examined potential mechanism(s) underlying this synergistic effect. Immunoblotting experiments of classical growth factor intermediary signalling pathways (PI 3-K-Akt-GSK-3 and Ras-Raf-MAPK) were performed using phospho-specific antibodies to assess activation state. We found that activation of Akt and MAPK correlated with neurite elongation and branching. However, using pharmacological inhibitors, we observed that a PI 3-K pathway involving both Akt and GSK-3 appeared to be more important for neurite extension and branching than MAPK-dependent signalling. In fact, inhibition of activation of MAPK with U0126 resulted in increased neuritic branching, possibly as a result of the concomitant increase observed in phospho-Akt. Furthermore, inhibition of GSK3 (which is negatively regulated by phosphorylation on S9/S21) also resulted in increased growth. Our data point to signalling convergence upon the PI 3-K-Akt-GSK-3 pathway that underlies the NGF plus IGF synergism. In addition, to our knowledge, this is the first report in primary neurons that inhibition of GSK3 results in an enhanced neurite growth.
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Affiliation(s)
- David M Jones
- Division of Basic Medical Sciences, Faculty of Medicine, Memorial University of Newfoundland, 300 Prince Philip Drive, St. John's, Newfoundland, Canada A1B 3V6
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33
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Lock LS, Frigault MM, Saucier C, Park M. Grb2-independent recruitment of Gab1 requires the C-terminal lobe and structural integrity of the Met receptor kinase domain. J Biol Chem 2003; 278:30083-90. [PMID: 12766170 DOI: 10.1074/jbc.m302675200] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The Gab1 docking protein forms a platform for the assembly of a multiprotein signaling complex downstream from receptor tyrosine kinases. In general, recruitment of Gab1 occurs indirectly, via the adapter protein Grb2. In addition, Gab1 interacts with the Met/hepatocyte growth factor receptor in a Grb2-independent manner. This interaction requires a Met binding domain (MBD) in Gab1 and is essential for Met-mediated epithelial morphogenesis. The Gab1 MBD has been proposed to act as a phosphotyrosine binding domain that binds Tyr-1349 in the Met receptor. We show that a 16-amino acid motif within the Gab1 MBD is sufficient for interaction with the Met receptor, suggesting that it is unlikely that the Gab1 MBD forms a structured domain. Alternatively, the structural integrity of the Met receptor, and residues upstream of Tyr-1349 located in the C-terminal lobe of the kinase domain, are required for Grb2-independent interaction with the Gab1 MBD. Moreover, the substitution of Tyr-1349 with an acidic residue allows for the recruitment of the Gab1 MBD and for phosphorylation of Gab1. We propose that Gab1 and the Met receptor interact in a novel manner, such that the activated kinase domain of Met and the negative charge of phosphotyrosine 1349 engage the Gab1 MBD as an extended peptide ligand.
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Affiliation(s)
- Lisa S Lock
- Department of Biochemistry, Molecular Oncology Group, McGill University Health Centre, Montreal, Quebec H3A 1A1, Canada
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34
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Holgado-Madruga M, Wong AJ. Gab1 is an integrator of cell death versus cell survival signals in oxidative stress. Mol Cell Biol 2003; 23:4471-84. [PMID: 12808090 PMCID: PMC164844 DOI: 10.1128/mcb.23.13.4471-4484.2003] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Upon the addition of different growth factors and cytokines, the Gab1 docking protein is tyrosine phosphorylated and in turn activates different signaling pathways. On the basis of the large body of evidence concerning cross talk between the signaling pathways activated by growth factors and oxidative stress, we decided to investigate the role of Gab1 in oxidative injury. We stimulated wild-type mouse embryo fibroblasts (MEF) or MEF with a homozygous deletion of the Gab1 gene (-/- MEF) with H(2)O(2). Our results show that Gab1 is phosphorylated in a dose- and time-dependent manner after H(2)O(2) triggering. Gab1 then recruits molecules such as SHP2, phosphatidylinositol 3-kinase (PI3K), and Shc. Gab1 phosphorylation is sensitive to the Src family kinase inhibitor PP2. Furthermore, we demonstrate that Gab1 is required for H(2)O(2)-induced c-Jun N-terminal kinase (JNK) activation but not for ERK2 or p38 activation. Reconstitution of Gab1 in -/- MEF rescues JNK activation, and we find that this is dependent on the SHP2 binding site in Gab1. Cell viability assays reveal that Gab1 has a dual role in cell survival: a positive one through its interaction with PI3K and a negative one through its interaction with SHP2. This is the first report identifying Gab1 as a component in oxidative stress signaling and one that is required for JNK activation.
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Affiliation(s)
- Marina Holgado-Madruga
- Department of Microbiology and Immunology, Kimmel Cancer Institute, Thomas Jefferson University, Philadelphia, Pennsylvania 19107, USA.
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35
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Tyson DR, Larkin S, Hamai Y, Bradshaw RA. PC12 cell activation by epidermal growth factor receptor: role of autophosphorylation sites. Int J Dev Neurosci 2003; 21:63-74. [PMID: 12615082 DOI: 10.1016/s0736-5748(02)00139-9] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
PC12 cells have been used as a model system for neuronal differentiation due to their ability to alter their phenotype to a sympathetic neuron-like cell in response to nerve growth factor or fibroblast growth factor. Under some conditions, epidermal growth factor (EGF) can also induce PC12 cells to differentiate. To study signaling from the EGF receptor without the confounding effects of endogenous EGF receptors we generated a chimeric receptor comprised of the ectodomain of platelet-derived growth factor (PDGF) receptor in-frame with the transmembrane and cytoplasmic domains of EGF receptor, termed PER. Expression of PER in PC12 cells confers the ability of PDGF to induce differentiation whereas PDGF has no effect on untransfected PC12 cells. This response is kinase activity-dependent since a kinase-deficient mutant (K721M) fails to induce differentiation in response to PDGF. Mutation of five tyrosine residues that are autophosphorylated in response to EGF either individually or in combination had minimal effects on the ability of these receptors to induce morphological PC12 cell differentiation. The PER mutant with all five autophosphorylation sites mutated to phenylalanine (5YF) was equivalently capable of interacting with several important signaling molecules, including Shc, Grb2, Gab1, phospholipase Cgamma, and Cbl. Furthermore, both the phosphatidylinositol 3-kinase (PI3K)/Akt and Ras/Erk pathways were activated in a sustained manner when PER or 5YF-expressing cells were stimulated with PDGF. Our results show that the five autophosphorylation sites in the extra-kinase C-terminal domain of EGFR are not required for the ability of EGFR to induce morphological differentiation of PC12 cells.
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Affiliation(s)
- Darren R Tyson
- Department of Physiology and Biophysics, University of California, Irvine, CA 92697-4560, USA.
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36
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Piiper A, Dikic I, Lutz MP, Leser J, Kronenberger B, Elez R, Cramer H, Müller-Esterl W, Zeuzem S. Cyclic AMP induces transactivation of the receptors for epidermal growth factor and nerve growth factor, thereby modulating activation of MAP kinase, Akt, and neurite outgrowth in PC12 cells. J Biol Chem 2002; 277:43623-30. [PMID: 12218049 DOI: 10.1074/jbc.m203926200] [Citation(s) in RCA: 72] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
In PC12 cells, a well studied model for neuronal differentiation, an elevation in the intracellular cAMP level increases cell survival, stimulates neurite outgrowth, and causes activation of extracellular signal-regulated protein kinase 1 and 2 (ERK1/2). Here we show that an increase in the intracellular cAMP concentration induces tyrosine phosphorylation of two receptor tyrosine kinases, i.e. the epidermal growth factor (EGF) receptor and the high affinity receptor for nerve growth factor (NGF), also termed Trk(A). cAMP-induced tyrosine phosphorylation of the EGF receptor is rapid and correlates with ERK1/2 activation. It occurs also in Panc-1, but not in human mesangial cells. cAMP-induced tyrosine phosphorylation of the NGF receptor is slower and correlates with Akt activation. Inhibition of EGF receptor tyrosine phosphorylation, but not of the NGF receptor, reduces cAMP-induced neurite outgrowth. Expression of dominant-negative Akt does not abolish cAMP-induced survival in serum-free media, but increases cAMP-induced ERK1/2 activation and neurite outgrowth. Together, our results demonstrate that cAMP induces dual signaling in PC12 cells: transactivation of the EGF receptor triggering the ERK1/2 pathway and neurite outgrowth; and transactivation of the NGF receptor promoting Akt activation and thereby modulating ERK1/2 activation and neurite outgrowth.
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Affiliation(s)
- Albrecht Piiper
- Department of Internal Medicine and Institute for Biochemistry II, Johann Wolfgang Goethe-University, D-60590 Frankfurt, Germany.
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37
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Reyes SD, Campagnoni AT. Two separate domains in the golli myelin basic proteins are responsible for nuclear targeting and process extension in transfected cells. J Neurosci Res 2002; 69:587-96. [PMID: 12210824 DOI: 10.1002/jnr.10319] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
The golli products of the myelin basic protein (MBP) gene are expressed in neurons and oligodendrocytes (OLs). In certain neuronal populations, golli proteins undergo translocation between the nucleus and cytoplasm/processes during development. The proteins consist of two domains, a golli domain of 133 amino acids and an MBP domain of variable length. One objective of this study was to identify the sequences responsible for nuclear targeting. Site-directed mutagenesis and deletion analyses were used to generate a series of golli-green fluorescent protein (GFP) DNA constructs that were transfected into OL and neuronal cell lines to follow localization by confocal microscopy. The results indicated that a 36-residue stretch in the MBP domain is essential for nuclear targeting, and the sequence appears to be a nontraditional localization signal motif. The studies also revealed that overexpression of golli proteins could induce dramatic changes in cell morphology. In OL lines, overexpression of intact golli proteins, or golli peptide alone, caused an increase in the length and number of processes, and the elaboration of membrane sheets. In the neuronal lines, there was a dramatic increase in number and length of extensions. The results, consistent with the timing of golli expression in cells during neural development, suggest that golli proteins may be involved in process formation/extension in OLs and neurons during development. These studies have defined two functional domains in the golli protein. Sequences in the MBP domain target the protein into the nucleus and sequences within the golli domain induce process sheet extension in OLs and neurons.
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Affiliation(s)
- Samuel D Reyes
- Developmental Biology Group, Neuropsychiatric Institute, University of California, Los Angeles, School of Medicine, Los Angeles, California, USA
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38
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Abstract
Nerve growth factor (NGF) induces dramatic axon growth from responsive embryonic peripheral neurons. However, the roles of the various NGF-triggered signaling cascades in determining specific axon morphological features remain unknown. Here, we transfected activated and inhibitory mutants of Trk effectors into sensory neurons lacking the proapoptotic protein Bax. This allowed axon growth to be studied in the absence of NGF, enabling us to observe the contributions of individual signaling mediators. While Ras was both necessary and sufficient for NGF-stimulated axon growth, the Ras effectors Raf and Akt induced distinct morphologies. Activated Raf-1 caused axon lengthening comparable to NGF, while active Akt increased axon caliber and branching. Our results suggest that the different Trk effector pathways mediate distinct morphological aspects of developing neurons.
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MESH Headings
- Animals
- Cell Differentiation/genetics
- Cell Size/genetics
- Female
- Fetus
- Ganglia, Spinal/cytology
- Ganglia, Spinal/embryology
- Ganglia, Spinal/metabolism
- Gene Expression/physiology
- Growth Cones/metabolism
- Growth Cones/ultrastructure
- MAP Kinase Kinase 1
- Male
- Mice
- Mice, Knockout
- Mitogen-Activated Protein Kinase Kinases/genetics
- Mitogen-Activated Protein Kinase Kinases/metabolism
- Mitogen-Activated Protein Kinases/genetics
- Mitogen-Activated Protein Kinases/metabolism
- Nerve Growth Factor/metabolism
- Neurons, Afferent/cytology
- Neurons, Afferent/metabolism
- Phosphatidylinositol 3-Kinases/genetics
- Phosphatidylinositol 3-Kinases/metabolism
- Protein Serine-Threonine Kinases/genetics
- Protein Serine-Threonine Kinases/metabolism
- Proto-Oncogene Proteins/deficiency
- Proto-Oncogene Proteins/genetics
- Proto-Oncogene Proteins c-akt
- Proto-Oncogene Proteins c-bcl-2
- Proto-Oncogene Proteins c-raf/deficiency
- Proto-Oncogene Proteins c-raf/genetics
- Receptor Protein-Tyrosine Kinases/genetics
- Receptor Protein-Tyrosine Kinases/metabolism
- Receptor, trkA/genetics
- Receptor, trkA/metabolism
- Receptor, trkC/genetics
- Receptor, trkC/metabolism
- Signal Transduction/genetics
- bcl-2-Associated X Protein
- ras Proteins/genetics
- ras Proteins/metabolism
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Affiliation(s)
- Annette Markus
- Neuroscience Center, University of North Carolina, 103 Mason Farm Road, Chapel Hill 27599, USA
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39
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Saito Y, Hojo Y, Tanimoto T, Abe JI, Berk BC. Protein kinase C-alpha and protein kinase C-epsilon are required for Grb2-associated binder-1 tyrosine phosphorylation in response to platelet-derived growth factor. J Biol Chem 2002; 277:23216-22. [PMID: 11940581 DOI: 10.1074/jbc.m200605200] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Grb2-associated binder-1 (Gab1) is an adapter protein related to the insulin receptor substrate family. It is a substrate for the insulin receptor as well as the epidermal growth factor (EGF) receptor and other receptor-tyrosine kinases. To investigate the role of Gab1 in signaling pathways downstream of growth factor receptors, we stimulated rat aortic vascular smooth muscle cells (VSMC) with EGF and platelet-derived growth factor (PDGF). Gab1 was tyrosine-phosphorylated by EGF and PDGF within 1 min. AG1478 (an EGF receptor kinase-specific inhibitor) failed to block PDGF-induced Gab1 tyrosine phosphorylation, suggesting that transactivated EGF receptor is not responsible for this signaling event. Because Gab1 associates with phospholipase Cgamma (PLCgamma), we studied the role of the PLCgamma pathway in Gab1 tyrosine phosphorylation. Gab1 tyrosine phosphorylation by PDGF was impaired in Chinese hamster ovary cells expressing mutant PDGFbeta receptor (Y977F/Y989F: lacking the binding site for PLCgamma). Pretreatment of VSMC with (a specific PLCgamma inhibitor) inhibited Gab1 tyrosine phosphorylation as well, indicating the importance of the PLCgamma pathway. Gab1 was tyrosine-phosphorylated by phorbol ester to the same extent as PDGF stimulation. Studies using antisense protein kinase C (PKC) oligonucleotides and specific inhibitors showed that PKCalpha and PKCepsilon are required for Gab1 tyrosine phosphorylation. Binding of Gab1 to the protein-tyrosine phosphatase SHP2 and phosphatidylinositol 3-kinase was significantly decreased by PLCgamma and/or PKC inhibition, suggesting the importance of the PLCgamma/PKC-dependent Gab1 tyrosine phosphorylation for the interaction with other signaling molecules. Because PDGF-mediated ERK activation is enhanced in Chinese hamster ovary cells that overexpress Gab1, Gab1 serves as an important link between PKC and ERK activation by PDGFbeta receptors in VSMC.
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Affiliation(s)
- Yuji Saito
- Center for Cardiovascular Research, University of Rochester, Rochester, New York 14642, USA
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Yu CF, Liu ZX, Cantley LG. ERK negatively regulates the epidermal growth factor-mediated interaction of Gab1 and the phosphatidylinositol 3-kinase. J Biol Chem 2002; 277:19382-8. [PMID: 11896055 DOI: 10.1074/jbc.m200732200] [Citation(s) in RCA: 108] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
We have examined the ability of epidermal growth factor (EGF)-stimulated ERK activation to regulate Grb2-associated binder-1 (Gab1)/phosphatidylinositol 3-kinase (PI3K) interactions. Inhibiting ERK activation with the MEK inhibitor U0126 increased the EGF-stimulated association of Gab1 with either full-length glutathione S-transferase-p85 or the p85 C-terminal Src homology 2 (SH2) domain, a result reproduced by co-immunoprecipitation of the native proteins from intact cells. This increased association of Gab1 and the PI3K correlates with an increase in PI3K activity and greater phosphorylation of Akt. This result is in direct contrast to what we have previously reported following HGF stimulation where MEK inhibition decreased the HGF-stimulated association of Gab1 and p85. In support of this divergent effect of ERK on Gab1/PI3K association following HGF and EGF stimulation, U0126 decreased the HGF-stimulated association of p85 and the Gab1 c-Met binding domain but did not alter the EGF-stimulated association of p85 and the c-Met binding domain. An examination of the mechanism of this effect revealed that the treatment of cells with EGF + U0126 increased the tyrosine phosphorylation of Gab1 as well as its association with another SH2-containing protein, SHP2. Furthermore, overexpression of a catalytically inactive form of SHP2 or pretreatment with pervanadate markedly increased EGF-stimulated Gab1 tyrosine phosphorylation. These experiments demonstrate that EGF and HGF-mediated ERK activation result in divergent effects on Gab1/PI3K signaling. HGF-stimulated ERK activation increases the Gab1/PI3K association, whereas EGF-stimulated ERK activation results in a decrease in the tyrosine phosphorylation of Gab1 and a decreased association with the PI3K. SHP2 is shown to associate with and dephosphorylate Gab1, suggesting that EGF-stimulated ERK might act through the regulation of SHP2.
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Affiliation(s)
- Cheng Fang Yu
- Department of Internal Medicine, Section of Nephrology, Yale University School of Medicine, New Haven, Connecticut 06520, USA.
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41
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Bisotto S, Fixman ED. Src-family tyrosine kinases, phosphoinositide 3-kinase and Gab1 regulate extracellular signal-regulated kinase 1 activation induced by the type A endothelin-1 G-protein-coupled receptor. Biochem J 2001; 360:77-85. [PMID: 11695994 PMCID: PMC1222204 DOI: 10.1042/0264-6021:3600077] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
The multisubstrate docking protein, growth-factor-receptor-bound protein 2-associated binder 1 (Gab1), which is phosphorylated on tyrosine residues following activation of receptor tyrosine kinases and cytokine receptors, regulates cell proliferation, survival and epithelial morphogenesis. Gab1 is also tyrosine phosphorylated following activation of G-protein-coupled receptors (GPCRs) where its function is poorly understood. To elucidate the role of Gab1 in GPCR signalling, we investigated the mechanism by which the type A endothelin-1 (ET-1) GPCR induced tyrosine phosphorylation of Gab1. Tyrosine phosphorylation of Gab1 induced by endothelin-1 was inhibited by PP1, a pharmacological inhibitor of Src-family tyrosine kinases. ET-1-induced Gab1 tyrosine phosphorylation was also inhibited by LY294002, which inhibits phosphoinositide 3-kinase (PI 3-kinase) enzymes. Inhibition of Src-family tyrosine kinases or PI 3-kinase also inhibited ET-1-induced activation of the mitogen activated protein kinase family member, extracellular signal-regulated kinase (ERK) 1. Thus we determined whether Gab1 regulated ET-1-induced ERK1 activation. Overexpression of wild-type Gab1 potentiated ET-1-induced activation of ERK1. Structure-function analyses of Gab1 indicated that mutant forms of Gab1 that do not bind the Src homology (SH) 2 domains of the p85 adapter subunit of PI 3-kinase or the SH2-domain-containing protein tyrosine phosphatase 2 (SHP-2) were impaired in their ability to potentiate ET-1-induced ERK1 activation. Taken together, our data indicate that PI 3-kinase and Src-family tyrosine kinases regulate ET-1-induced Gab1 tyrosine phosphorylation, which, in turn, induces ERK1 activation via PI 3-kinase- and SHP-2-dependent pathways.
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Affiliation(s)
- S Bisotto
- Meakins-Christie Laboratories, Department of Medicine, McGill University, 3626 St. Urbain, Montreal, QC, H2X 2P2, Canada
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Abstract
Nerve growth factor (NGF) was discovered 50 years ago as a molecule that promoted the survival and differentiation of sensory and sympathetic neurons. Its roles in neural development have been characterized extensively, but recent findings point to an unexpected diversity of NGF actions and indicate that developmental effects are only one aspect of the biology of NGF. This article considers expanded roles for NGF that are associated with the dynamically regulated production of NGF and its receptors that begins in development, extends throughout adult life and aging, and involves a surprising variety of neurons, glia, and nonneural cells. Particular attention is given to a growing body of evidence that suggests that among other roles, endogenous NGF signaling subserves neuroprotective and repair functions. The analysis points to many interesting unanswered questions and to the potential for continuing research on NGF to substantially enhance our understanding of the mechanisms and treatment of neurological disorders.
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Affiliation(s)
- M V Sofroniew
- Department of Neurobiology and Brain Research Institute, University of California Los Angeles, Los Angeles, California 90095-1763, USA.
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43
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Gual P, Giordano S, Anguissola S, Comoglio PM. Differential requirement of the last C-terminal tail of Met receptor for cell transformation and invasiveness. Oncogene 2001; 20:5493-502. [PMID: 11571647 DOI: 10.1038/sj.onc.1204713] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2001] [Revised: 06/05/2001] [Accepted: 06/08/2001] [Indexed: 11/09/2022]
Abstract
Biological responses to Hepatocyte Growth Factor are mediated by the tyrosine kinase receptor encoded by the Met oncogene. Under physiological conditions, Met triggers a multi-step genetic program called 'invasive growth' including cell-dissociation, invasion of extracellular matrices and growth. When constitutively activated, Met can induce cell transformation and metastasis. Phosphorylation of two docking tyrosines in the receptor tail is essential for all biological responses. To investigate the role of the C-terminal part of Met, we have generated mutants lacking either the last 26 or 47 amino acids. As expected, mutants lacking the docking sites fail to mediate cell transformation and invasion. Interestingly, while Met Delta26 can mediate invasion, its transforming ability is severely impaired. Moreover, the lack of the last 26 amino acids strongly reduces Met ability to phosphorylate substrates in vitro and in vivo. These data indicate that the last 26 amino acids are required to confer the kinase its full enzymatic activity, which is critical for cell transformation but dispensable for invasive properties. Finally, we also show that up-regulation of Met enzymatic activity by insertion of a point mutation in the kinase domain (M1250T) overcomes the regulatory role played by the last 26 amino acids of the tail. It is concluded that the C-terminal domain of Met is crucial not only for recruitment of transducers but also for regulation of receptor enzymatic activity.
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Affiliation(s)
- P Gual
- Institute for Cancer Research and Treatment (IRCC), University of Torino Medical School, Str. Prov. 142, Km 3.95, 10060 Candiolo, Italy
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Abstract
We investigated a role for endogenous Rap1, a small monomeric GTP-binding protein of the Ras family, in nerve growth factor (NGF) signaling in PC12 cells. Although both epidermal growth factor (EGF) and NGF caused transient activation of Ras, only NGF induced the activation of Rap1. Moreover, Rap1 activation was sustained for hours, an effect that matched the sustained activation of the mitogen-activated protein kinase (MAPK) pathway. To investigate the molecular basis for Rap1 activation, we examined complexes containing C3G, a guanine nucleotide exchange factor for Rap1, and CrkL, an adapter protein known to influence Rap1 signaling. NGF induced the formation of a long-lived complex containing C3G/CrkL/Shp2/Gab2/TrkA. Linking the complex to Rap1 activation, we coprecipitated activated TrkA and activated MAPK with activated Rap1 in NGF-treated cells. Confocal microscopy and subcellular fractionation showed that activated Rap1 and the other proteins of the signaling complex were present in endosomes. Pretreatment of PC12 cells with brefeldin A (BFA), which disrupts the Golgi and endosomal compartments, had little effect on Ras activation but strongly inhibited NGF-induced Rap1 activation and continuing MAPK activation. We propose that endosomes are a site from which NGF induces the prolonged activation of Rap1 and MAPK.
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45
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Harper SJ, LoGrasso P. Signalling for survival and death in neurones: the role of stress-activated kinases, JNK and p38. Cell Signal 2001; 13:299-310. [PMID: 11369511 DOI: 10.1016/s0898-6568(01)00148-6] [Citation(s) in RCA: 230] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The pathways involved in neuronal survival or death have been extensively studied mainly in cell lines. Recent evidence has suggested that activation of the stress activated pathways, jun N-terminal kinase (JNK) and p38 may play important roles in neuronal cell death or regeneration. In this review we will discuss these pahtways in detail. We will examine the evidence that these pathways are important in neuronal cell death. Finally we will review the evidence that inhibitors of these pathways have a neuroprotective effect both in vitro and in vivo.
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Affiliation(s)
- S J Harper
- Department of Pharmacology, Merck Sharp and Dohme Research Laboratories, Neuroscience Research Centre, Terlings Park, Essex CM20 2QR, Harlow, UK.
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46
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Fan S, Ma YX, Gao M, Yuan RQ, Meng Q, Goldberg ID, Rosen EM. The multisubstrate adapter Gab1 regulates hepatocyte growth factor (scatter factor)-c-Met signaling for cell survival and DNA repair. Mol Cell Biol 2001; 21:4968-84. [PMID: 11438654 PMCID: PMC87224 DOI: 10.1128/mcb.21.15.4968-4984.2001] [Citation(s) in RCA: 73] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Hepatocyte growth factor (scatter factor) (HGF/SF) is a pleiotrophic mediator of epithelial cell motility, morphogenesis, angiogenesis, and tumorigenesis. HGF/SF protects cells against DNA damage by a pathway from its receptor c-Met to phosphatidylinositol 3-kinase (PI3K) to c-Akt, resulting in enhanced DNA repair and decreased apoptosis. We now show that protection against the DNA-damaging agent adriamycin (ADR; topoisomerase IIalpha inhibitor) requires the Grb2-binding site of c-Met, and overexpression of the Grb2-associated binder Gab1 (a multisubstrate adapter required for epithelial morphogenesis) inhibits the ability of HGF/SF to protect MDCK epithelial cells against ADR. In contrast to Gab1 and its homolog Gab2, overexpression of c-Cb1, another multisubstrate adapter that associates with c-Met, did not affect protection. Gab1 blocked the ability of HGF/SF to cause the sustained activation of c-Akt and c-Akt signaling (FKHR phosphorylation). The Gab1 inhibition of sustained c-Akt activation and of cell protection did not require the Gab1 pleckstrin homology or SHP2 phosphatase-binding domain but did require the PI3K-binding domain. HGF/SF protection of parental MDCK cells was blocked by wortmannin, expression of PTEN, and dominant negative mutants of p85 (regulatory subunit of PI3K), Akt, and Pak1; the protection of cells overexpressing Gab1 was restored by wild-type or activated mutants of p85, Akt, and Pak1. These findings suggest that the adapter Gab1 may redirect c-Met signaling through PI3K away from a c-Akt/Pak1 cell survival pathway.
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Affiliation(s)
- S Fan
- Department of Radiation Oncology, Long Island Jewish Medical Center, The Long Island Campus for the Albert Einstein College of Medicine, New Hyde Park, New York 11040, USA
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Rakhit S, Pyne S, Pyne NJ. Nerve growth factor stimulation of p42/p44 mitogen-activated protein kinase in PC12 cells: role of G(i/o), G protein-coupled receptor kinase 2, beta-arrestin I, and endocytic processing. Mol Pharmacol 2001; 60:63-70. [PMID: 11408601 DOI: 10.1124/mol.60.1.63] [Citation(s) in RCA: 75] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
In this study, we have shown that nerve growth factor (NGF)-dependent activation of the p42/p44 mitogen-activated protein kinase (p42/p44 MAPK) pathway in PC12 cells can be partially blocked by pertussis toxin (which inactivates the G proteins G(i/o)). This suggests that the Trk A receptor may use a G protein-coupled receptor pathway to signal to p42/p44 MAPK. This was supported by data showing that the NGF-dependent activation of p42/p44 MAPK is potentiated in cells transfected with G protein-coupled receptor kinase 2 (GRK2) or beta-arrestin I. Moreover, GRK2 is constitutively bound with the Trk A receptor, whereas NGF stimulates the pertussis toxin-sensitive binding of beta-arrestin I to the TrkA receptor-GRK2 complex. Both GRK2 and beta-arrestin I are involved in clathrin-mediated endocytic signaling to p42/p44 MAPK. Indeed, inhibitors of clathrin-mediated endocytosis (e.g., monodansylcadaverine, concanavalin A, and hyperosmolar sucrose) reduced the NGF-dependent activation of p42/p44 MAPK. Finally, we have found that the G protein-coupled receptor-dependent component regulating p42/p44 MAPK is required for NGF-induced differentiation of PC12 cells. Thus, NGF-dependent inhibition of DNA synthesis was partially blocked by PD098059 (inhibitor of MAPK kinase-1 activation) and pertussis toxin. Our findings are the first to show that the Trk A receptor uses a classic G protein-coupled receptor-signaling pathway to promote differentiation of PC12 cells.
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Affiliation(s)
- S Rakhit
- Department of Physiology and Pharmacology, Strathclyde Institute for Biomedical Sciences, University of Strathclyde, Glasgow, Scotland, United Kingdom
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48
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Ong SH, Hadari YR, Gotoh N, Guy GR, Schlessinger J, Lax I. Stimulation of phosphatidylinositol 3-kinase by fibroblast growth factor receptors is mediated by coordinated recruitment of multiple docking proteins. Proc Natl Acad Sci U S A 2001; 98:6074-9. [PMID: 11353842 PMCID: PMC33424 DOI: 10.1073/pnas.111114298] [Citation(s) in RCA: 247] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
The docking protein FRS2 is a major downstream effector that links fibroblast growth factor (FGF) and nerve growth factor receptors with the Ras/mitogen-activated protein kinase signaling cascade. In this report, we demonstrate that FRS2 also plays a pivotal role in FGF-induced recruitment and activation of phosphatidylinositol 3-kinase (PI3-kinase). We demonstrate that tyrosine phosphorylation of FRS2alpha leads to Grb2-mediated complex formation with the docking protein Gab1 and its tyrosine phosphorylation, resulting in the recruitment and activation of PI3-kinase. Furthermore, Grb2 bound to tyrosine-phosphorylated FRS2 through its SH2 domain interacts primarily via its carboxyl-terminal SH3 domain with a proline-rich region in Gab1 and via its amino-terminal SH3 domain with the nucleotide exchange factor Sos1. Assembly of FRS2alpha:Grb2:Gab1 complex induced by FGF stimulation results in activation of PI3-kinase and downstream effector proteins such as the S/T kinase Akt, whose cellular localization and activity are regulated by products of PI3-kinase. These experiments reveal a unique mechanism for generation of signal diversity by growth factor-induced coordinated assembly of a multidocking protein complex that can activate the Ras/mitogen-activated protein kinase cascade to induce cell proliferation and differentiation, and PI3-kinase to activate a mediator of a cell survival pathway.
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Affiliation(s)
- S H Ong
- Department of Pharmacology and The Skirball Institute, New York University, Medical School, New York, NY 10016, USA
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49
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Bouscary D, Lecoq-Lafon C, Chrétien S, Zompi S, Fichelson S, Muller O, Porteu F, Dusanter-Fourt I, Gisselbrecht S, Mayeux P, Lacombe C. Role of Gab proteins in phosphatidylinositol 3-kinase activation by thrombopoietin (Tpo). Oncogene 2001; 20:2197-204. [PMID: 11402314 DOI: 10.1038/sj.onc.1204317] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2000] [Revised: 01/22/2001] [Accepted: 01/30/2001] [Indexed: 12/18/2022]
Abstract
In this study, we show that upon thrombopoietin (Tpo) stimulation the two adapter proteins Gab1 and Gab2 are strongly tyrosine phosphorylated and associated with Shc, SHP2, PI 3-kinase and Grb2 in mpl-expressing UT7 cells. Although Gab1 and Gab2 seem to mediate overlapping biological signals in many cells, only Gab1 is expressed and phosphorylated in response to Tpo in primary human megakaryocytic progenitors; furthermore, it associates with the same proteins. Although a low level of tyrosine phosphorylated IRS-2 protein is also detected in PI 3-kinase immunoprecipitates, Gab proteins are the essential proteins associated with PI 3-kinase after Tpo stimulation. We demonstrate that, albeit no association is detected between the Tpo receptor mpl and Gab proteins, Y112 located in the C-terminal cytoplasmic domain of mpl is required for Gab1/2 tyrosine phosphorylation. Gab proteins are not tyrosine phosphorylated after Tpo stimulation of UT-7 and Ba/F3 cells expressing a mpl mutant lacking Y112. Moreover, no activation of the PI 3-kinase/Akt pathway is observed in cells expressing this mpl mutant. Finally, we show that this mutant does not allow cell proliferation, thereby confirming that PI 3-kinase activation is required for Tpo-induced cell proliferation.
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Affiliation(s)
- D Bouscary
- Institut Cochin de Génétique Moléculaire (ICGM), Institut National de la Santé et de la Recherche Médicale (INSERM U363), Université René Descartes, France
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50
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Harada S, Esch GL, Holgado-Madruga M, Wong AJ. Grb-2-associated binder-1 is involved in insulin-induced egr-1 gene expression through its phosphatidylinositol 3'-kinase binding site. DNA Cell Biol 2001; 20:223-9. [PMID: 11403719 DOI: 10.1089/104454901750219107] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The Grb2-associated binder-1 (Gab1) is one of the major adapter molecules downstream of growth factor receptor signaling. Even though insulin causes tyrosine phosphorylation of Gab1, its role in insulin signaling has not been identified yet. We have demonstrated that insulin increased expression of early growth response gene-1 (egr-1), which is one of the most important transcription factors involved in cell proliferation and differentiation. In the present study, the possible role of Gab1 in insulin-induced egr-1 expression was studied using Rat1 fibroblasts expressing human insulin receptors and wildtype Gab1 (HIRc/Gab1(WT)), Gab1 with three tyrosines in the phosphatidylinositol (PI) 3'-kinase binding domain mutated to phenylalanine (HIRc/Gab1(DeltaPI3K)), or histidinol resistance only (HIRc/HIS). Insulin-induced egr-1 expression in HIRc/Gab1(DeltaPI3K) cells was much lower than in the other cells, as determined by Northern blot analysis. These results suggest that Gab1 is involved in the signaling pathway for insulin-induced egr-1 expression through increasing PI3'-kinase activity. The MAP kinase activity increased less with insulin treatment in HIRc/Gab1(DeltaPI3K) cells than in other cells. Inhibition of MAP kinase by the MEK inhibitor completely abolished insulin-induced egr-1 expression. These results suggest that Gab1 increases MAP kinase activity through its PI3'-kinase binding site, which then leads to egr-1 expression. Our results indicate that Gab1 is involved in the control of egr-1 expression regulated by insulin.
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Affiliation(s)
- S Harada
- Department of Pathology and Laboratory Medicine, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, USA.
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