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Báez-Flores J, Rodríguez-Martín M, Lacal J. The therapeutic potential of neurofibromin signaling pathways and binding partners. Commun Biol 2023; 6:436. [PMID: 37081086 PMCID: PMC10119308 DOI: 10.1038/s42003-023-04815-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2022] [Accepted: 04/05/2023] [Indexed: 04/22/2023] Open
Abstract
Neurofibromin controls many cell processes, such as growth, learning, and memory. If neurofibromin is not working properly, it can lead to health problems, including issues with the nervous, skeletal, and cardiovascular systems and cancer. This review examines neurofibromin's binding partners, signaling pathways and potential therapeutic targets. In addition, it summarizes the different post-translational modifications that can affect neurofibromin's interactions with other molecules. It is essential to investigate the molecular mechanisms that underlie neurofibromin variants in order to provide with functional connections between neurofibromin and its associated proteins for possible therapeutic targets based on its biological function.
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Affiliation(s)
- Juan Báez-Flores
- Laboratory of Functional Genetics of Rare Diseases, Department of Microbiology and Genetics, University of Salamanca (USAL), 37007, Salamanca, Spain
- Institute of Biomedical Research of Salamanca (IBSAL), 37007, Salamanca, Spain
| | - Mario Rodríguez-Martín
- Laboratory of Functional Genetics of Rare Diseases, Department of Microbiology and Genetics, University of Salamanca (USAL), 37007, Salamanca, Spain
- Institute of Biomedical Research of Salamanca (IBSAL), 37007, Salamanca, Spain
| | - Jesus Lacal
- Laboratory of Functional Genetics of Rare Diseases, Department of Microbiology and Genetics, University of Salamanca (USAL), 37007, Salamanca, Spain.
- Institute of Biomedical Research of Salamanca (IBSAL), 37007, Salamanca, Spain.
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2
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Tabebi M, Frikha F, Volpe M, Gimm O, Söderkvist P. Domain landscapes of somatic NF1 mutations in pheochromocytoma and paraganglioma. Gene 2023; 872:147432. [PMID: 37062455 DOI: 10.1016/j.gene.2023.147432] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2023] [Revised: 03/23/2023] [Accepted: 04/11/2023] [Indexed: 04/18/2023]
Abstract
Pheochromocytoma and paraganglioma (PPGL), are rare neuroendocrine tumors arising from the adrenal medulla and extra-adrenal paraganglia, respectively. Up to about 60% are explained by germline or somatic mutations in one of the major known susceptibility genes e.g., inNF1,RET,VHL, SDHx,MAXandHRAS. Targeted Next Generation Sequencing was performed in 14 sporadic tumors using a panel including 26 susceptibility genes to characterize the mutation profile. A total of 6 germline and 8 somatic variants were identified. The most frequent somatic mutations were found in NF1(36%), four have not been reported earlier in PCC or PGL. Gene expression profile analysis showed that NF1 mutated tumors are classified into RTK3 subtype, cluster 2, with a high expression of genes associated with chromaffin cell differentiation, and into a RTK2 subtype, cluster 2, as well with overexpression of genes associated with cortisol biosynthesis. On the other hand, by analyzing the entire probe set on the array and TCGA data, ALDOC was found as the most significantly down regulated gene in NF1-mutated tumors compared to NF1-wild-type. Differential gene expression analysis showed a significant difference between Nt - and Ct-NF1 domains in mutated tumors probably engaging different cellular pathways. Notably, we had a metastatic PCC with a Ct-NF1 frameshift mutation and when performing protein docking analysis, Ct-NF1 showed an interaction with Nt-FAK suggesting their involvement in cell adhesion and cell growth. These results show that depending on the location of the NF1-mutation different pathways are activated in PPGLs. Further studies are required to clarify their clinical significance.
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Affiliation(s)
- Mouna Tabebi
- Department of Biomedical and Clinical Sciences (BKV), Linköping University, 58183 Linköping, Sweden.
| | - Fakher Frikha
- Laboratory of Molecular and Cellular Screening Processes, Center of Biotechnology of Sfax, University of Sfax, Sfax, Tunisia
| | - Massimiliano Volpe
- Clinical Genomics Linköping, Linköping University, 581 83 Linköping, Sweden
| | - Oliver Gimm
- Department of Surgery and Department of Biomedical and Clinical Sciences (BKV), Linköping University, 58183 Linköping, Sweden
| | - Peter Söderkvist
- Department of Biomedical and Clinical Sciences (BKV), Linköping University, 58183 Linköping, Sweden; Clinical Genomics Linköping, Linköping University, 581 83 Linköping, Sweden
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3
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Xu J, Zhang Y, Zhu K, Li J, Guan Y, He X, Jin X, Bai G, Hu L. Clinical characteristics and in silico analysis of congenital pseudarthrosis of the tibia combined with neurofibromatosis type 1 caused by a novel NF1 mutation. Front Genet 2022; 13:991314. [PMID: 36246612 PMCID: PMC9553987 DOI: 10.3389/fgene.2022.991314] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2022] [Accepted: 08/29/2022] [Indexed: 11/24/2022] Open
Abstract
Congenital pseudarthrosis of the tibia (CPT) is a rare congenital bone malformation, which has a strong relationship with Neurofibromatosis type 1 (NF1). NF1 is an autosomal dominant disease leading to multisystem disorders. Here, we presented the genotypic and phenotypic characteristics of one unique case of a five-generation Chinese family. The proband was CPT accompanied with NF1 due to NF1 mutation. The proband developed severe early-onset CPT combined with NF1 after birth. Appearance photos and X-ray images of the left limb of the proband showed significant bone malformation. Slit-lamp examination showed Lisch nodules in both eyes of the proband. Whole-exome sequencing (WES) and Sanger sequencing confirmed the truncation variant of NF1 (c.871G>T, p. E291*). Sequence conservative and evolutionary conservation analysis indicated that the novel mutation (p.E291*) was highly conserved. The truncated mutation led to the loss of functional domains, including CSRD, GRD, TBD, SEC14-PH, CTD, and NLS. It may explain why the mutation led to a severe clinical feature. Our report expands the genotypic spectrum of NF1 mutations and the phenotypic spectrum of CPT combined with NF1.
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Affiliation(s)
- Jingfang Xu
- Department of Orthopaedics, The Children’s Hospital, Zhejiang University School of Medicine, National Clinical Research Center for Child Health, Hangzhou, China
| | - Ying Zhang
- Institute of Translational Medicine, Zhejiang University School of Medicine, Hangzhou, China
| | - Kun Zhu
- Department of Pathology, The Children’s Hospital, Zhejiang University School of Medicine, National Clinical Research Center for Child Health, Hangzhou, China
| | - Jiabin Li
- Department of Pharmacy, The Children’s Hospital, Zhejiang University School of Medicine, National Clinical Research Center for Child Health, Hangzhou, China
| | - Yuelin Guan
- The Children’s Hospital, Zhejiang University School of Medicine, National Clinical Research Center for Child Health, Hangzhou, China
| | - Xinyu He
- The Children’s Hospital, Zhejiang University School of Medicine, National Clinical Research Center for Child Health, Hangzhou, China
| | - Xuejing Jin
- Centre for Evidence-based Chinese Medicine, Beijing University of Chinese Medicine, Beijing, China
| | - Guannan Bai
- Department of Child Health Care, The Children’s Hospital, Zhejiang University School of Medicine, National Clinical Research Center for Child Health, Hangzhou, China
- *Correspondence: Guannan Bai, ; Lidan Hu,
| | - Lidan Hu
- The Children’s Hospital, Zhejiang University School of Medicine, National Clinical Research Center for Child Health, Hangzhou, China
- *Correspondence: Guannan Bai, ; Lidan Hu,
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4
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Rodionov RN, Jarzebska N, Burdin D, Todorov V, Martens-Lobenhoffer J, Hofmann A, Kolouschek A, Cordasic N, Jacobi J, Rubets E, Morawietz H, O'Sullivan JF, Markov AG, Bornstein SR, Hilgers K, Maas R, Pfluecke C, Chen Y, Bode-Böger SM, Hugo CPM, Hohenstein B, Weiss N. Overexpression of alanine-glyoxylate aminotransferase 2 protects from asymmetric dimethylarginine-induced endothelial dysfunction and aortic remodeling. Sci Rep 2022; 12:9381. [PMID: 35672381 DOI: 10.1038/s41598-022-13169-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2021] [Accepted: 05/20/2022] [Indexed: 12/03/2022] Open
Abstract
Elevated plasma concentrations of asymmetric dimethylarginine (ADMA) are associated with an increased risk of mortality and adverse cardiovascular outcomes. ADMA can be metabolized by dimethylarginine dimethylaminohydrolases (DDAHs) and by alanine-glyoxylate aminotransferase 2 (AGXT2). Deletion of DDAH1 in mice leads to elevation of ADMA in plasma and increase in blood pressure, while overexpression of human DDAH1 is associated with a lower plasma ADMA concentration and protective cardiovascular effects. The possible role of alternative metabolism of ADMA by AGXT2 remains to be elucidated. The goal of the current study was to test the hypothesis that transgenic overexpression of AGXT2 leads to lowering of plasma levels of ADMA and protection from vascular damage in the setting of DDAH1 deficiency. We generated transgenic mice (TG) with ubiquitous overexpression of AGXT2. qPCR and Western Blot confirmed the expression of the transgene. Systemic ADMA levels were decreased by 15% in TG mice. In comparison with wild type animals plasma levels of asymmetric dimethylguanidino valeric acid (ADGV), the AGXT2 associated metabolite of ADMA, were six times higher. We crossed AGXT2 TG mice with DDAH1 knockout mice and observed that upregulation of AGXT2 lowers plasma ADMA and pulse pressure and protects the mice from endothelial dysfunction and adverse aortic remodeling. Upregulation of AGXT2 led to lowering of ADMA levels and protection from ADMA-induced vascular damage in the setting of DDAH1 deficiency. This is especially important, because all the efforts to develop pharmacological ADMA-lowering interventions by means of upregulation of DDAHs have been unsuccessful.
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5
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Scheer M, Leisz S, Sorge E, Storozhuk O, Prell J, Ho I, Harder A. Neurofibromatosis Type 1 Gene Alterations Define Specific Features of a Subset of Glioblastomas. Int J Mol Sci 2021; 23:352. [PMID: 35008787 DOI: 10.3390/ijms23010352] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2021] [Revised: 12/14/2021] [Accepted: 12/24/2021] [Indexed: 02/08/2023] Open
Abstract
Neurofibromatosis type 1 (NF1) gene mutations or alterations occur within neurofibromatosis type 1 as well as in many different malignant tumours on the somatic level. In glioblastoma, NF1 loss of function plays a major role in inducing the mesenchymal (MES) subtype and, therefore defining the most aggressive glioblastoma. This is associated with an immune signature and mediated via the NF1–MAPK–FOSL1 axis. Specifically, increased invasion seems to be regulated via mutations in the leucine-rich domain (LRD) of the NF1 gene product neurofibromin. Novel targets for therapy may arise from neurofibromin deficiency-associated cellular mechanisms that are summarised in this review.
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6
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Kopaliani I, Jarzebska N, Billoff S, Kolouschek A, Martens-Lobenhoffer J, Bornstein SR, Bode-Böger SM, Ragavan VN, Weiss N, Mangoni AA, Deussen A, Rodionov RN. Overexpression of dimethylarginine dimethylaminohydrolase 1 protects from angiotensin II-induced cardiac hypertrophy and vascular remodeling. Am J Physiol Heart Circ Physiol 2021; 321:H825-H838. [PMID: 34533401 DOI: 10.1152/ajpheart.00064.2021] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/08/2021] [Accepted: 09/01/2021] [Indexed: 11/22/2022]
Abstract
Cardiovascular complications are the leading cause of death, and elevated levels of asymmetric dimethyarginine (ADMA), an endogenous inhibitor of nitric oxide synthase, are implicated in their pathophysiology. We investigated the role of dimethylarginine dimethylaminohydrolase 1 (DDAH1), an enzyme hydrolyzing ADMA, in prevention of cardiovascular remodeling during hypertension. We hypothesized that the animals overexpressing DDAH1 will be protected from angiotensin II (ANG II)-induced end organ damage. Angiotensin II (ANG II) was infused in two doses: 0.75 and 1.5 mg/kg/day in DDAH1 transgenic mice (DDAH1 TG) and wild-type (WT) littermates for 2 or 4 wk. Echocardiography was performed in the first and fourth weeks of the infusion, systolic blood pressure (SBP) was measured weekly, and cardiac hypertrophy and vascular remodeling was assessed by histology. Increase in SBP after 1 wk of ANG II infusion was not different between the groups, whereas TG mice had lower SBP at later time points. TG mice were protected from cardiovascular remodeling after 2 wk of ANG II infusion in the high dose and after 4 wk in the moderate dose. TG mice had higher left ventricular lumen-to-wall ratio, lower cardiomyocyte cross-sectional area, and less interstitial fibrosis compared with WT controls. In aorta, TG mice had less adventitial fibrosis, lower medial thickness with preserved elastin content, lower counts of inflammatory cells, lower levels of active matrix metalloproteinase-2, and showed better endothelium-dependent relaxation. We demonstrated that overexpression of DDAH1 protects from ANG II-induced cardiovascular remodeling and progression of hypertension by preserving endothelial function and limiting inflammation.NEW & NOTEWORTHY We showed that overexpression of dimethylarginine dimethylaminohydrolase 1 (DDAH1) protects from angiotensin II-induced cardiovascular damage, progression of hypertension, and adverse vascular remodeling in vivo. This protective effect is associated with decreased levels of asymmetric dimethylarginine, preservation of endothelial function, inhibition of cardiovascular inflammation, and lower activity of matrix metalloproteinase-2. Our findings are highly clinically relevant, because they suggest that upregulation of DDAH1 might be a promising therapeutic approach against angiotensin II-induced end organ damage.
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Affiliation(s)
- Irakli Kopaliani
- Department of Physiology, Medical Faculty, Dresden University of Technology, Dresden, Germany
| | - Natalia Jarzebska
- University Center for Vascular Medicine, Dresden University of Technology, Dresden, Germany
- Department of Anesthesiology and Critical Care Medicine, University Hospital Dresden, Dresden University of Technology, Dresden, Germany
- Department of Internal Medicine III, University Hospital Carl Gustav Carus, Dresden University of Technology, Dresden, Germany
| | - Silke Billoff
- University Center for Vascular Medicine, Dresden University of Technology, Dresden, Germany
| | - Anne Kolouschek
- University Center for Vascular Medicine, Dresden University of Technology, Dresden, Germany
| | | | - Stefan R Bornstein
- University Clinic and Polyclinic III, Dresden University of Technology, Dresden, Germany
| | - Stefanie M Bode-Böger
- Institute of Clinical Pharmacology, Otto-von-Guericke University, Magdeburg, Germany
| | - Vinitha N Ragavan
- University Center for Vascular Medicine, Dresden University of Technology, Dresden, Germany
- Department of Clinical Pharmacology, College of Medicine and Public Health, Flinders University and Flinders Medical Centre, Adelaide, South Australia, Australia
| | - Norbert Weiss
- University Center for Vascular Medicine, Dresden University of Technology, Dresden, Germany
- University Clinic and Polyclinic III, Dresden University of Technology, Dresden, Germany
| | - Arduino A Mangoni
- Department of Clinical Pharmacology, College of Medicine and Public Health, Flinders University and Flinders Medical Centre, Adelaide, South Australia, Australia
| | - Andreas Deussen
- Department of Physiology, Medical Faculty, Dresden University of Technology, Dresden, Germany
| | - Roman N Rodionov
- University Center for Vascular Medicine, Dresden University of Technology, Dresden, Germany
- University Clinic and Polyclinic III, Dresden University of Technology, Dresden, Germany
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7
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Bergoug M, Doudeau M, Godin F, Mosrin C, Vallée B, Bénédetti H. Neurofibromin Structure, Functions and Regulation. Cells 2020; 9:cells9112365. [PMID: 33121128 PMCID: PMC7692384 DOI: 10.3390/cells9112365] [Citation(s) in RCA: 55] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2020] [Revised: 10/21/2020] [Accepted: 10/26/2020] [Indexed: 12/13/2022] Open
Abstract
Neurofibromin is a large and multifunctional protein encoded by the tumor suppressor gene NF1, mutations of which cause the tumor predisposition syndrome neurofibromatosis type 1 (NF1). Over the last three decades, studies of neurofibromin structure, interacting partners, and functions have shown that it is involved in several cell signaling pathways, including the Ras/MAPK, Akt/mTOR, ROCK/LIMK/cofilin, and cAMP/PKA pathways, and regulates many fundamental cellular processes, such as proliferation and migration, cytoskeletal dynamics, neurite outgrowth, dendritic-spine density, and dopamine levels. The crystallographic structure has been resolved for two of its functional domains, GRD (GAP-related (GTPase-activating protein) domain) and SecPH, and its post-translational modifications studied, showing it to be localized to several cell compartments. These findings have been of particular interest in the identification of many therapeutic targets and in the proposal of various therapeutic strategies to treat the symptoms of NF1. In this review, we provide an overview of the literature on neurofibromin structure, function, interactions, and regulation and highlight the relationships between them.
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8
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Bellazzo A, Collavin L. Cutting the Brakes on Ras-Cytoplasmic GAPs as Targets of Inactivation in Cancer. Cancers (Basel) 2020; 12:cancers12103066. [PMID: 33096593 PMCID: PMC7588890 DOI: 10.3390/cancers12103066] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2020] [Revised: 10/11/2020] [Accepted: 10/15/2020] [Indexed: 12/16/2022] Open
Abstract
Simple Summary GTPase-Activating Proteins (RasGAPs) are a group of structurally related proteins with a fundamental role in controlling the activity of Ras in normal and cancer cells. In particular, loss of function of RasGAPs may contribute to aberrant Ras activation in cancer. Here we review the multiple molecular mechanisms and factors that are involved in downregulating RasGAPs expression and functions in cancer. Additionally, we discuss how extracellular stimuli from the tumor microenvironment can control RasGAPs expression and activity in cancer cells and stromal cells, indirectly affecting Ras activation, with implications for cancer development and progression. Abstract The Ras pathway is frequently deregulated in cancer, actively contributing to tumor development and progression. Oncogenic activation of the Ras pathway is commonly due to point mutation of one of the three Ras genes, which occurs in almost one third of human cancers. In the absence of Ras mutation, the pathway is frequently activated by alternative means, including the loss of function of Ras inhibitors. Among Ras inhibitors, the GTPase-Activating Proteins (RasGAPs) are major players, given their ability to modulate multiple cancer-related pathways. In fact, most RasGAPs also have a multi-domain structure that allows them to act as scaffold or adaptor proteins, affecting additional oncogenic cascades. In cancer cells, various mechanisms can cause the loss of function of Ras inhibitors; here, we review the available evidence of RasGAP inactivation in cancer, with a specific focus on the mechanisms. We also consider extracellular inputs that can affect RasGAP levels and functions, implicating that specific conditions in the tumor microenvironment can foster or counteract Ras signaling through negative or positive modulation of RasGAPs. A better understanding of these conditions might have relevant clinical repercussions, since treatments to restore or enhance the function of RasGAPs in cancer would help circumvent the intrinsic difficulty of directly targeting the Ras protein.
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9
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Cui XW, Ren JY, Gu YH, Li QF, Wang ZC. NF1, Neurofibromin and Gene Therapy: Prospects of Next-Generation Therapy. Curr Gene Ther 2020; 20:100-108. [PMID: 32767931 DOI: 10.2174/1566523220666200806111451] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2020] [Revised: 07/10/2020] [Accepted: 07/14/2020] [Indexed: 12/28/2022]
Abstract
Neurofibromatosis type 1 [NF1] is an autosomal dominant genetic disorder affecting multiple organs. NF1 is well known for its various clinical manifestations, including café-au-late macules, Lisch nodules, bone deformity and neurofibromas. However, there is no effective therapy for NF1. Current therapies are aimed at alleviating NF1 clinical symptoms but not curing the disease. By altering pathogenic genes, gene therapy regulates cell activities at the nucleotide level. In this review, we described the structure and functions of neurofibromin domains, including GAP-related domain [GRD], cysteine-serine rich domain [CSRD], leucine-rich domain [LRD] and C-terminal domain [CTD], which respectively alter downstream pathways. By transfecting isolated sequences of these domains, researchers can partially restore normal cell functions in neurofibroma cell lines. Furthermore, recombinant transgene sequences may be designed to encode truncated proteins, which is functional and easy to be packaged into viral vectors. In addition, the treatment effect of gene therapy is also determined by various factors such as the vectors selection, transgene packaging strategies and drug administration. We summarized multiple NF1 gene therapy strategies and discussed their feasibility from multiple angles. Different protein domains alter the function and downstream pathways of neurofibromin.
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Affiliation(s)
- Xi-Wei Cui
- Department of Plastic and Reconstructive Surgery, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 200011, China
| | - Jie-Yi Ren
- Department of Plastic and Reconstructive Surgery, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 200011, China
| | - Yi-Hui Gu
- Department of Plastic and Reconstructive Surgery, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 200011, China
| | - Qing-Feng Li
- Department of Plastic and Reconstructive Surgery, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 200011, China
| | - Zhi-Chao Wang
- Department of Plastic and Reconstructive Surgery, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 200011, China
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10
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Jarzebska N, Mangoni AA, Martens-Lobenhoffer J, Bode-Böger SM, Rodionov RN. The Second Life of Methylarginines as Cardiovascular Targets. Int J Mol Sci 2019; 20:E4592. [PMID: 31533264 DOI: 10.3390/ijms20184592] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2019] [Revised: 09/13/2019] [Accepted: 09/15/2019] [Indexed: 02/07/2023] Open
Abstract
Endogenous methylarginines were proposed as cardiovascular risk factors more than two decades ago, however, so far, this knowledge has not led to the development of novel therapeutic approaches. The initial studies were primarily focused on the endogenous inhibitors of nitric oxide synthases asymmetric dimethylarginine (ADMA) and monomethylarginine (MMA) and the main enzyme regulating their clearance dimethylarginine dimethylaminohydrolase 1 (DDAH1). To date, all the screens for DDAH1 activators performed with the purified recombinant DDAH1 enzyme have not yielded any promising hits, which is probably the main reason why interest towards this research field has started to fade. The relative contribution of the second DDAH isoenzyme DDAH2 towards ADMA and MMA clearance is still a matter of controversy. ADMA, MMA and symmetric dimethylarginine (SDMA) are also metabolized by alanine: glyoxylate aminotransferase 2 (AGXT2), however, in addition to methylarginines, this enzyme also has several cardiovascular protective substrates, so the net effect of possible therapeutic targeting of AGXT2 is currently unclear. Recent studies on regulation and functions of the enzymes metabolizing methylarginines have given a second life to this research direction. Our review discusses the latest discoveries and controversies in the field and proposes novel directions for targeting methylarginines in clinical settings.
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11
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Fadhlullah SFB, Halim NBA, Yeo JYT, Ho RLY, Um P, Ang BT, Tang C, Ng WH, Virshup DM, Ho IAW. Pathogenic mutations in neurofibromin identifies a leucine-rich domain regulating glioma cell invasiveness. Oncogene 2019; 38:5367-5380. [PMID: 30967630 PMCID: PMC6755990 DOI: 10.1038/s41388-019-0809-3] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2018] [Revised: 03/14/2019] [Accepted: 03/23/2019] [Indexed: 12/25/2022]
Abstract
Glioblastoma (GBM) is the most aggressive tumor of the brain. NF1, a tumor suppressor gene and RAS-GTPase, is one of the highly mutated genes in GBM. Dysregulated NF1 expression promotes cell invasion, proliferation, and tumorigenesis. Loss of NF1 expression in glioblastoma is associated with increased aggressiveness of the tumor. Here, we show that NF1-loss in patient-derived glioma cells using shRNA increases self-renewal, heightens cell invasion, and promotes mesenchymal subtype and epithelial mesenchymal transition-specific gene expression that enhances tumorigenesis. The neurofibromin protein contains at least four major domains, with the GAP-related domain being the most well-studied. In this study, we report that the leucine-rich domain (LRD) of neurofibromin inhibits invasion of human glioblastoma cells without affecting their proliferation. Moreover, under conditions tested, the NF1-LRD fails to hydrolyze Ras-GTP to Ras-GDP, suggesting that its suppressive function is independent of Ras signaling. We further demonstrate that rare variants within the NF1-LRD domain found in a subset of the patients are pathogenic and reduce NF1-LRD’s invasion suppressive function. Taken together, our results show, for the first time, that NF1-LRD inhibits glioma invasion, and provides evidence of a previously unrecognized function of NF1-LRD in glioma biology.
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Affiliation(s)
- Siti Farah Bte Fadhlullah
- Molecular Neurotherapeutics Laboratory, National Neuroscience Institute, Singapore, 308433, Singapore.,Lucence Diagnostics Pte Ltd., Singapore, Singapore
| | | | - Jacqueline Y T Yeo
- Molecular Neurotherapeutics Laboratory, National Neuroscience Institute, Singapore, 308433, Singapore
| | - Rachel L Y Ho
- Molecular Neurotherapeutics Laboratory, National Neuroscience Institute, Singapore, 308433, Singapore
| | - Phoebe Um
- Molecular Neurotherapeutics Laboratory, National Neuroscience Institute, Singapore, 308433, Singapore.,University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Beng Ti Ang
- Department of Neurosurgery, National Neuroscience Institute, Singapore, 308433, Singapore.,Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, 119228, Singapore.,Singapore Institute for Clinical Sciences, A*STAR, Singapore, 117609, Singapore.,Duke-NUS Medical School, Singapore, 169857, Singapore
| | - Carol Tang
- Department of Research, National Neuroscience Institute, Singapore, 308433, Singapore.,Program in Cancer and Stem Cell Biology, Duke-NUS Medical School, Singapore, 169857, Singapore.,Division of Cellular and Molecular Research, National Cancer Centre, Singapore, 169610, Singapore
| | - Wai H Ng
- Department of Neurosurgery, National Neuroscience Institute, Singapore, 308433, Singapore
| | - David M Virshup
- Program in Cancer and Stem Cell Biology, Duke-NUS Medical School, Singapore, 169857, Singapore.,Department of Pediatrics, Duke University School of Medicine, Durham, NC, 27703, USA
| | - Ivy A W Ho
- Molecular Neurotherapeutics Laboratory, National Neuroscience Institute, Singapore, 308433, Singapore. .,Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, 119228, Singapore. .,Duke-NUS Medical School, Singapore, 169857, Singapore.
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12
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Abstract
Ras-specific GTPase-activating proteins (RasGAPs) down-regulate the biological activity of Ras proteins by accelerating their intrinsic rate of GTP hydrolysis, basically by a transition state stabilizing mechanism. Oncogenic Ras is commonly not sensitive to RasGAPs caused by interference of mutants with the electronic or steric requirements of the transition state, resulting in up-regulation of activated Ras in respective cells. RasGAPs are modular proteins containing a helical catalytic RasGAP module surrounded by smaller domains that are frequently involved in the subcellular localization or contributing to regulatory features of their host proteins. In this review, we summarize current knowledge about RasGAP structure, mechanism, regulation, and dual-substrate specificity and discuss in some detail neurofibromin, one of the most important negative Ras regulators in cellular growth control and neuronal function.
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Affiliation(s)
- Klaus Scheffzek
- Division of Biological Chemistry (Biocenter), Medical University of Innsbruck, A-6020 Innsbruck, Austria
| | - Giridhar Shivalingaiah
- Division of Biological Chemistry (Biocenter), Medical University of Innsbruck, A-6020 Innsbruck, Austria
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Zhang Z, Zhu LL, Jiang HS, Chen H, Chen Y, Dai YT. Demethylation treatment restores erectile function in a rat model of hyperhomocysteinemia. Asian J Androl 2017; 18:763-8. [PMID: 26585696 PMCID: PMC5000801 DOI: 10.4103/1008-682x.163271] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Methylation modification is an important cellular mechanism of gene expression regulation. Dimethylarginine dimethylaminohydrolase-2 (DDAH-2) protein is a pivotal molecular for endothelium function. To explore the effects of 5-aza-deoxycytidine (5-aza), a demethylation agent, in hyperhomocysteinemia (hhcy)-related erectile dysfunction (ED) rats, 5-aza (1 mg kg−1) was administrated to Sprague-Dawley hhcy-rats induced by supplemented methionine chow diet. Erectile function, nitric oxide-cyclic guanosine monophosphate (NO-cGMP) levels, expression of DDAH-2 protein and promoter methylation status of DDAH-2 were studied in the corpora cavernosa. We found that supplemented methionine diet induced a high homocysteine level after 6 weeks of treatment. DDAH-2 protein was down-regulated in the corpora cavernosa while the administration of 5-aza up-regulated DDAH-2 expression and restored erectile function. The methionine-fed rats showed high methylation levels of DDAH-2 promoter region while the group treated with 5-aza demonstrated lower-methylation levels when compared to the methionine-fed group. Besides, the administration of 5-aza improved NO and cGMP levels in methionine-fed rats. Therefore, the methylation mechanism involves in ED pathogenesis, and demethylation offers a potential new strategy for ED treatment.
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Affiliation(s)
- Zheng Zhang
- Department of Andrology, Affiliated Drum Tower Hospital, School of Medicine, Nanjing University, Nanjing, China
| | - Lei-Lei Zhu
- Department of Andrology, Affiliated Drum Tower Hospital, School of Medicine, Nanjing University, Nanjing, China
| | - He-Song Jiang
- Department of Andrology, Affiliated Drum Tower Hospital, School of Medicine, Nanjing University, Nanjing, China
| | - Hai Chen
- Department of Andrology, Affiliated Drum Tower Hospital, School of Medicine, Nanjing University, Nanjing, China
| | - Yun Chen
- Department of Andrology, Affiliated Drum Tower Hospital, School of Medicine, Nanjing University, Nanjing, China
| | - Yu-Tian Dai
- Department of Andrology, Affiliated Drum Tower Hospital, School of Medicine, Nanjing University, Nanjing, China
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Murphy RB, Tommasi S, Lewis BC, Mangoni AA. Inhibitors of the Hydrolytic Enzyme Dimethylarginine Dimethylaminohydrolase (DDAH): Discovery, Synthesis and Development. Molecules 2016; 21:E615. [PMID: 27187323 DOI: 10.3390/molecules21050615] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2016] [Revised: 04/19/2016] [Accepted: 05/04/2016] [Indexed: 02/07/2023] Open
Abstract
Dimethylarginine dimethylaminohydrolase (DDAH) is a highly conserved hydrolytic enzyme found in numerous species, including bacteria, rodents, and humans. In humans, the DDAH-1 isoform is known to metabolize endogenous asymmetric dimethylarginine (ADMA) and monomethyl arginine (l-NMMA), with ADMA proposed to be a putative marker of cardiovascular disease. Current literature reports identify the DDAH family of enzymes as a potential therapeutic target in the regulation of nitric oxide (NO) production, mediated via its biochemical interaction with the nitric oxide synthase (NOS) family of enzymes. Increased DDAH expression and NO production have been linked to multiple pathological conditions, specifically, cancer, neurodegenerative disorders, and septic shock. As such, the discovery, chemical synthesis, and development of DDAH inhibitors as potential drug candidates represent a growing field of interest. This review article summarizes the current knowledge on DDAH inhibition and the derived pharmacokinetic parameters of the main DDAH inhibitors reported in the literature. Furthermore, current methods of development and chemical synthetic pathways are discussed.
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Krappmann M, de Boer AR, Kool DRW, Irth H, Letzel T. Mass spectrometric real-time monitoring of an enzymatic phosphorylation assay using internal standards and data-handling freeware. Rapid Commun Mass Spectrom 2016; 30:1019-1030. [PMID: 27003039 DOI: 10.1002/rcm.7529] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/07/2015] [Revised: 02/01/2016] [Accepted: 02/02/2016] [Indexed: 06/05/2023]
Abstract
RATIONALE Continuous-flow reaction detection systems (monitoring enzymatic reactions with mass spectrometry (MS)) lack quantitative values so far. Therefore, two independent internal standards (IS) are implemented in a way that the online system stability can be observed, quantitative conversion values for substrate and product can be obtained and they can be used as mass calibration standards for high MS accuracy. METHODS An application previously developed for the MS detection of peptide phosphorylation by cAMP-dependent protein kinase A (PKA) (De Boer et al., Anal. Bioanal. Chem. 2005, 381, 647-655) was transferred to a continuous-flow reaction detection system. This enzymatic reaction, involving enzyme activation as well as the transfer of a phosphate group from ATP to a peptide substrate, was used to prove the compatibility of a quantitative enzymatic assay in a continuous-flow real-time system (connected to MS). RESULTS Moreover (using internal standards), the critical parameter reaction temperature (including solution density variations depending on temperature) was studied in the continuous-flow mixing system. Furthermore, two substrates (malantide and kemptide), two enzyme types (catalytic subunit of PKA and complete PKA) and one inhibitor were tested to determine system robustness and long-term availability. Even spraying solutions that contained significant amount of MS contaminants (e.g. the polluted catalytic subunit) resulted in quantifiable MS signal intensities. Subsequent recalculations using the internal standards led to results representing the power of this application. CONCLUSIONS The presented methodology and the data evaluation with available Achroma freeware enable the direct coupling of biochemical assays with quantitative MS detection. Monitoring changes such as temperature, reaction time, inhibition, or compound concentrations can be observed quantitatively and thus enzymatic activity can be calculated.
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Affiliation(s)
- Michael Krappmann
- Zentrum für Forschung und Weiterbildung, Weihenstephan-Triesdorf - University of Applied Science, Am Staudengarten 7, D-85354, Freising-Weihenstephan, Germany
| | - Arjen R de Boer
- Faculty of Sciences, Division of Chemistry, Department of Analytical Chemistry and Applied Spectroscopy, Free University of Amsterdam, De Boelelaan 1083, NL-1081 HV, Amsterdam, The Netherlands
| | - Daniël R W Kool
- Faculty of Sciences, Division of Chemistry, Department of Analytical Chemistry and Applied Spectroscopy, Free University of Amsterdam, De Boelelaan 1083, NL-1081 HV, Amsterdam, The Netherlands
| | - Hubertus Irth
- Faculty of Sciences, Division of Chemistry, Department of Analytical Chemistry and Applied Spectroscopy, Free University of Amsterdam, De Boelelaan 1083, NL-1081 HV, Amsterdam, The Netherlands
| | - Thomas Letzel
- Faculty of Sciences, Division of Chemistry, Department of Analytical Chemistry and Applied Spectroscopy, Free University of Amsterdam, De Boelelaan 1083, NL-1081 HV, Amsterdam, The Netherlands
- Analytical Research Group, Chair of Urban Water Systems Engineering, Technical University of Munich, Am Coulombwall 8, D-85748, Garching, Germany
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Lumicisi BA, Cartwright JE, Leslie K, Wallace AE, Whitley GS. Inhibition of DDAH1, but not DDAH2, results in apoptosis of a human trophoblast cell line in response to TRAIL. Hum Reprod 2015; 30:1813-9. [PMID: 26082478 PMCID: PMC4507332 DOI: 10.1093/humrep/dev138] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2014] [Accepted: 05/21/2015] [Indexed: 01/14/2023] Open
Abstract
STUDY QUESTION Does inhibition of dimethylarginine dimethylaminohydrolase (DDAH) increase the sensitivity of trophoblasts to TRAIL-induced apoptosis? SUMMARY ANSWER Inhibition of DDAH1, but not DDAH2, increases the sensitivity of trophoblasts to TRAIL-induced apoptosis. WHAT IS KNOWN ALREADY Successful human pregnancy is dependent on adequate trophoblast invasion and remodelling of the maternal spiral arteries. Increased trophoblast apoptosis is seen in pregnancies complicated by pre-eclampsia. The mechanism underlying this increase is unknown. We have previously shown that nitric oxide (NO) is involved in regulating trophoblast motility and invasion, and have also demonstrated an important role for NO in regulating trophoblast sensitivity to apoptotic stimuli. DDAH is an enzyme that metabolizes asymmetric dimethylarginine (ADMA), an endogenous inhibitor of NO synthesis, previously shown to be elevated in the plasma of pre-eclamptic mothers. STUDY DESIGN, SIZE, DURATION This study used the human extravillous trophoblast-derived cell line SGHPL-4 cells. All experiments were performed at least three times. PARTICIPANTS/MATERIALS, SETTING, METHODS The effect of DDAH on trophoblast apoptosis was examined using siRNA and time-lapse microscopy. Changes in the expression of DDAH were followed by PCR and western blot analysis. Receptor expression was followed by flow cytometry. MAIN RESULTS AND THE ROLE OF CHANCE Inhibiting the expression of DDAH1, but not DDAH2, resulted in a significant increase in the sensitivity of the EVT cell line SGHPL-4 to tumour necrosis factor related apoptosis inducing ligand (TRAIL) induced apoptosis (P < 0.01). This response could be mimicked by the addition of Asymmetric Dimethylarginine (ADMA), an endogenous inhibitor of NO synthesis and the substrate for both isoforms of DDAH. We further showed that this increased sensitivity to apoptosis is accompanied by a significant increase in the expression of TRAIL receptor 2 (TR2; P < 0.05) but not TRAIL receptor 1 (TR1). LIMITATIONS, REASONS FOR CAUTION This study was performed only in vitro using a well characterized trophoblast cell line, SGHPL-4, derived from first trimester extravillous trophoblasts. WIDER IMPLICATIONS OF THE FINDINGS This study provides new insight into the role of the DDAH/ADMA pathway in the regulation of trophoblast function. Both dysregulation of DDAH and the accumulation of ADMA have been associated with the development of pre-eclampsia. This is the first study to implicate the DDAH/ADMA pathway as a mechanism that might underlie the poor trophoblast invasion seen in this common pregnancy disorder. STUDY FUNDING/COMPETING INTEREST(S) B.A.L. was supported by a grant from Action Medical Research UK (SP4577). A.E.W. was supported by a grant from the Wellcome Trust (091550). There are no competing interests and the authors have no conflict interest to declare.
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Affiliation(s)
- B A Lumicisi
- Reproductive and Cardiovascular Research Group, Institute of Cardiovascular and Cell Sciences, St George's University of London, Cranmer Terrace, London SW17 0RE, UK
| | - J E Cartwright
- Reproductive and Cardiovascular Research Group, Institute of Cardiovascular and Cell Sciences, St George's University of London, Cranmer Terrace, London SW17 0RE, UK
| | - K Leslie
- Reproductive and Cardiovascular Research Group, Institute of Cardiovascular and Cell Sciences, St George's University of London, Cranmer Terrace, London SW17 0RE, UK
| | - A E Wallace
- Reproductive and Cardiovascular Research Group, Institute of Cardiovascular and Cell Sciences, St George's University of London, Cranmer Terrace, London SW17 0RE, UK
| | - G S Whitley
- Reproductive and Cardiovascular Research Group, Institute of Cardiovascular and Cell Sciences, St George's University of London, Cranmer Terrace, London SW17 0RE, UK
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Abstract
Neurofibromatosis type 1 (NF1) is a common genetic disorder that predisposes affected individuals to tumours. The NF1 gene encodes a RAS GTPase-activating protein called neurofibromin and is one of several genes that (when mutant) affect RAS-MAPK signalling, causing related diseases collectively known as RASopathies. Several RASopathies, beyond NF1, are cancer predisposition syndromes. Somatic NF1 mutations also occur in 5-10% of human sporadic cancers and may contribute to resistance to therapy. To highlight areas for investigation in RASopathies and sporadic tumours with NF1 mutations, we summarize current knowledge of NF1 disease, the NF1 gene and neurofibromin, neurofibromin signalling pathways and recent developments in NF1 therapeutics.
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Affiliation(s)
- Nancy Ratner
- Division of Experimental Hematology and Cancer Biology, Cancer and Blood Diseases Institute, Cincinnati Children's Hospital, 3333 Burnet Avenue, Cincinnati, Ohio 45229, USA
| | - Shyra J Miller
- Division of Experimental Hematology and Cancer Biology, Cancer and Blood Diseases Institute, Cincinnati Children's Hospital, 3333 Burnet Avenue, Cincinnati, Ohio 45229, USA
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Maertens O, Cichowski K. An expanding role for RAS GTPase activating proteins (RAS GAPs) in cancer. Adv Biol Regul 2014; 55:1-14. [PMID: 24814062 DOI: 10.1016/j.jbior.2014.04.002] [Citation(s) in RCA: 119] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2014] [Revised: 04/16/2014] [Accepted: 04/16/2014] [Indexed: 10/25/2022]
Abstract
The RAS pathway is one of the most commonly deregulated pathways in human cancer. Mutations in RAS genes occur in nearly 30% of all human tumors. However in some tumor types RAS mutations are conspicuously absent or rare, despite the fact that RAS and downstream effector pathways are hyperactivated. Recently, RAS GTPase Activating Proteins (RAS GAPs) have emerged as an expanding class of tumor suppressors that, when inactivated, provide an alternative mechanism of activating RAS. RAS GAPs normally turn off RAS by catalyzing the hydrolysis of RAS-GTP. As such, the loss of a RAS GAP would be expected to promote excessive RAS activation. Indeed, this is the case for the NF1 gene, which plays an established role in a familial tumor predisposition syndrome and a variety of sporadic cancers. However, there are 13 additional RAS GAP family members in the human genome. We are only now beginning to understand why there are so many RAS GAPs, how they differentially function, and what their potential role(s) in human cancer are. This review will focus on our current understanding of RAS GAPs in human disease and will highlight important outstanding questions.
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Affiliation(s)
- Ophélia Maertens
- Genetics Division, Department of Medicine, Brigham and Women's Hospital, Boston, MA 02115, USA; Harvard Medical School, Boston, MA 02115, USA
| | - Karen Cichowski
- Genetics Division, Department of Medicine, Brigham and Women's Hospital, Boston, MA 02115, USA; Harvard Medical School, Boston, MA 02115, USA; Ludwig Center at Dana-Farber/Harvard Cancer Center, Boston, MA 02115, USA.
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Zhang P, Xu X, Hu X, Wang H, Fassett J, Huo Y, Chen Y, Bache RJ. DDAH1 deficiency attenuates endothelial cell cycle progression and angiogenesis. PLoS One 2013; 8:e79444. [PMID: 24260221 PMCID: PMC3832548 DOI: 10.1371/journal.pone.0079444] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2013] [Accepted: 09/23/2013] [Indexed: 11/18/2022] Open
Abstract
Asymmetric dimethylarginine (ADMA) is an endogenous inhibitor of nitric oxide (NO) synthase (NOS). ADMA is eliminated largely by the action of dimethylarginine dimethylaminohydrolase1 (DDAH1). Decreased DDAH activity is found in several pathological conditions and is associated with increased risk of vascular disease. Overexpression of DDAH1 has been shown to augment endothelial proliferation and angiogenesis. To better understand the mechanism by which DDAH1 influences endothelial proliferation, this study examined the effect of DDAH1 deficiency on cell cycle progression and the expression of some cell cycle master regulatory proteins. DDAH1 KO decreased in vivo Matrigel angiogenesis and depressed endothelial repair in a mouse model of carotid artery wire injury. DDAH1 deficiency decreased VEGF expression in HUVEC and increased NF1 expression in both HUVEC and DDAH1 KO mice. The expression of active Ras could overcome the decreased VEGF expression caused by the DDAH1 depletion. The addition of VEGF and knockdown NF1 could both restore proliferation in cells with DDAH1 depletion. Flow cytometry analysis revealed that DDAH1 sRNAi knockdown in HUVEC caused G1 and G2/M arrest that was associated with decreased expression of CDC2, CDC25C, cyclin D1 and cyclin E. MEF cells from DDAH1 KO mice also demonstrated G2/M arrest that was associated with decreased cyclin D1 expression and Akt activity. Our findings indicate that DDAH1 exerts effects on cyclin D1 and cyclin E expression through multiple mechanisms, including VEGF, the NO/cGMP/PKG pathway, the Ras/PI3K/Akt pathway, and NF1 expression. Loss of DDAH1 effects on these pathways results in impaired endothelial cell proliferation and decreased angiogenesis. The findings provide background information that may be useful in the development of therapeutic strategies to manipulate DDAH1 expression in cardiovascular diseases or tumor angiogenesis.
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Affiliation(s)
- Ping Zhang
- Cardiovascular Division, Department of Medicine, University of Minnesota Medical School, Minneapolis, Minnesota, United States of America
- * E-mail:
| | - Xin Xu
- Cardiovascular Division, Department of Medicine, University of Minnesota Medical School, Minneapolis, Minnesota, United States of America
| | - Xinli Hu
- Institute of Molecular Medicine, Peking University, Beijing, China
| | - Huan Wang
- Cardiovascular Division, Department of Medicine, University of Minnesota Medical School, Minneapolis, Minnesota, United States of America
| | - John Fassett
- Cardiovascular Division, Department of Medicine, University of Minnesota Medical School, Minneapolis, Minnesota, United States of America
| | - Yuqing Huo
- Vascular Biology Center, Department of Cellular Biology and Anatomy, Medical College of Georgia, Georgia Health Sciences University, Augusta, Georgia, United States of America
| | - Yingjie Chen
- Cardiovascular Division, Department of Medicine, University of Minnesota Medical School, Minneapolis, Minnesota, United States of America
| | - Robert J. Bache
- Cardiovascular Division, Department of Medicine, University of Minnesota Medical School, Minneapolis, Minnesota, United States of America
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Saratsis AM, Yadavilli S, Magge S, Rood BR, Perez J, Hill DA, Hwang E, Kilburn L, Packer RJ, Nazarian J. Insights into pediatric diffuse intrinsic pontine glioma through proteomic analysis of cerebrospinal fluid. Neuro Oncol 2012; 14:547-60. [PMID: 22492959 DOI: 10.1093/neuonc/nos067] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Diffuse intrinsic pontine glioma (DIPG) is a leading cause of brain tumor-related death in children. DIPG is not surgically resectable, resulting in a paucity of tissue available for molecular studies. As such, tumor biology is poorly understood, and, currently, there are no effective treatments. In the absence of frozen tumor specimens, body fluids--such as cerebrospinal fluid (CSF), serum, and urine--can serve as more readily accessible vehicles for detecting tumor-secreted proteins. We analyzed a total of 76 specimens, including CSF, serum, urine, and normal and tumor brainstem tissue. Protein profiling of CSF from patients with DIPG was generated by mass spectrometry using an LTQ-Orbitrap-XL and database search using the Sequest algorithm. Quantitative and statistical analyses were performed with ProteoIQ and Partek Genomics Suite. A total of 528 unique proteins were identified, 71% of which are known secreted proteins. CSF proteomic analysis revealed selective upregulation of Cyclophillin A (CypA) and dimethylarginase 1 (DDAH1) in DIPG (n = 10), compared with controls (n = 4). Protein expression was further validated with Western blot analysis and immunohistochemical assays using CSF, brain tissue, serum, and urine from DIPG and control specimens. Immunohistochemical staining showed selective upregulation of secreted but not cytosolic CypA and DDAH1 in patients with DIPG. In this study, we present the first comprehensive protein profile of CSF specimens from patients with DIPG to demonstrate selective expression of tumor proteins potentially involved in brainstem gliomagenesis. Detection of secreted CypA and DDAH1 in serum and urine has potential clinical application, with implications for assessing treatment response and detecting tumor recurrence in patients with DIPG.
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Affiliation(s)
- Amanda M Saratsis
- Department of Neurosurgery, Georgetown University Hospital, Research Center for Genetic Medicine, Children's National Medical Center NW, Washington, DC 20010, USA.
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Wang S, Hu CP, Yuan Q, Zhang WF, Zhou Z, Nie SD, Jiang JL, Li YJ. Dimethylarginine dimethylaminohydrolase 1 regulates nerve growth factor-promoted differentiation of PC12 cells in a nitric oxide-dependent but asymmetric dimethylargenine-independent manner. J Neurosci Res 2012; 90:1209-17. [DOI: 10.1002/jnr.23009] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2011] [Revised: 11/05/2011] [Accepted: 11/18/2011] [Indexed: 11/10/2022]
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Wang HF, Shih YT, Chen CY, Chao HW, Lee MJ, Hsueh YP. Valosin-containing protein and neurofibromin interact to regulate dendritic spine density. J Clin Invest 2011; 121:4820-37. [PMID: 22105171 DOI: 10.1172/jci45677] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2010] [Accepted: 09/21/2011] [Indexed: 01/11/2023] Open
Abstract
Inclusion body myopathy with Paget disease of bone and frontotemporal dementia (IBMPFD) is an autosomal dominant disorder characterized by progressive myopathy that is often accompanied by bone weakening and/or frontotemporal dementia. Although it is known to be caused by mutations in the gene encoding valosin-containing protein (VCP), the underlying disease mechanism remains elusive. Like IBMPFD, neurofibromatosis type 1 (NF1) is an autosomal dominant disorder. Neurofibromin, the protein encoded by the NF1 gene, has been shown to regulate synaptogenesis. Here, we show that neurofibromin and VCP interact and work together to control the density of dendritic spines. Certain mutations identified in IBMPFD and NF1 patients reduced the interaction between VCP and neurofibromin and impaired spinogenesis. The functions of neurofibromin and VCP in spinogenesis were shown to correlate with the learning disability and dementia phenotypes seen in patients with IBMPFD. Consistent with the previous finding that treatment with a statin rescues behavioral defects in Nf1(+/-) mice and providing further support for our hypothesis that there is crosstalk between neurofibromin and VCP, statin exposure neutralized the effect of VCP knockdown on spinogenesis in cultured hippocampal neurons. The data presented here demonstrate that there is a link between IBMPFD and NF1 and indicate a role for VCP in synapse formation.
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Affiliation(s)
- Hsiao-Fang Wang
- Institute of Molecular Biology, Academia Sinica, Taipei, Taiwan
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23
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Boult JK, Walker-Samuel S, Jamin Y, Leiper JM, Whitley GSJ, Robinson SP. Active site mutant dimethylarginine dimethylaminohydrolase 1 expression confers an intermediate tumour phenotype in C6 gliomas. J Pathol 2011; 225:344-52. [PMID: 21590769 DOI: 10.1002/path.2904] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2011] [Revised: 02/16/2011] [Accepted: 03/17/2011] [Indexed: 12/11/2022]
Abstract
Dimethylarginine dimethylaminohydrolase (DDAH) metabolizes the endogenous inhibitor of nitric oxide synthesis, asymmetric dimethylarginine (ADMA). Constitutive over-expression of DDAH1, the isoform primarily associated with neuronal nitric oxide synthase (nNOS) results in increased tumour growth and vascularization, and elevated VEGF secretion. To address whether DDAH1-mediated tumour growth is reliant upon the enzymatic activity of DDAH1, cell lines expressing an active site mutant of DDAH1 incapable of metabolizing ADMA were created. Xenografts derived from these cell lines grew significantly faster than those derived from control cells, yet not as fast as those over-expressing wild-type DDAH1. VEGF expression in DDAH1 mutant-expressing tumours did not differ from control tumours but was significantly lower than that of wild-type DDAH1-over-expressing tumours. Fluorescence microscopy for CD31 and pimonidazole adduct formation demonstrated that DDAH1 mutant-expressing tumours had a lower endothelial content and demonstrated less hypoxia, respectively, than wild-type DDAH1-expressing tumours. However, there was no difference in uptake of the perfusion marker Hoechst 33342. Non-invasive multiparametric quantitative MRI, including the measurement of native T(1) and T(2) relaxation times and apparent water diffusion coefficient, was indicative of higher cellularity in DDAH1-expressing xenografts, which was confirmed by histological quantification of necrosis. C6 xenografts expressing active site mutant DDAH1 displayed an intermediate phenotype between tumours over-expressing wild-type DDAH1 and control tumours. These data suggest that enhanced VEGF expression downstream of DDAH1 was dependent upon ADMA metabolism, but that the DDAH1-mediated increase in tumour growth was only partially dependent upon its enzymatic activity, and therefore must involve an as-yet unidentified mechanism. DDAH1 is an important mediator of tumour progression, but appears to have addition roles independent of its metabolism of ADMA, which need to be considered in therapeutic strategies targeted against the NO/DDAH pathway in cancer.
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Affiliation(s)
- Jessica Kr Boult
- CRUK and EPSRC Cancer Imaging Centre, The Institute of Cancer Research and Royal Marsden NHS Trust, Sutton, Surrey, UK
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24
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Leiper J, Nandi M. The therapeutic potential of targeting endogenous inhibitors of nitric oxide synthesis. Nat Rev Drug Discov 2011; 10:277-91. [DOI: 10.1038/nrd3358] [Citation(s) in RCA: 118] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
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25
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Pullamsetti SS, Savai R, Schaefer MB, Wilhelm J, Ghofrani HA, Weissmann N, Schudt C, Fleming I, Mayer K, Leiper J, Seeger W, Grimminger F, Schermuly RT. cAMP phosphodiesterase inhibitors increases nitric oxide production by modulating dimethylarginine dimethylaminohydrolases. Circulation 2011; 123:1194-204. [PMID: 21382892 DOI: 10.1161/circulationaha.110.941484] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND Pulmonary arterial hypertension is characterized by a progressive increase in pulmonary vascular resistance caused by endothelial dysfunction, inward vascular remodeling, and severe loss of precapillary pulmonary vessel cross-sectional area. Asymmetrical dimethylarginine (ADMA), an endogenous nitric oxide synthase inhibitor, and its metabolizing enzyme dimethylarginine dimethylaminohydrolase (DDAH) play important roles in endothelial dysfunction. We investigated whether combined phosphodiesterase (PDE) 3 and 4 inhibition ameliorates endothelial function by regulating the ADMA-DDAH axis. METHODS AND RESULTS We investigated the effects of the PDE3/4 inhibitor tolafentrine in vitro on endothelial cell survival, proliferation, and apoptosis. Effects of tolafentrine on the endothelial nitric oxide synthase/nitric oxide pathway, DDAH expression, DDAH promoter activity, and cytokine release from endothelial cells and their subsequent influence on DDAH expression were investigated. In monocrotaline-induced pulmonary arterial hypertension in rats, the effects of inhaled tolafentrine on DDAH expression and activity were investigated. Real-time-polymerase chain reaction, immunocytochemistry, and PDE activity assays suggested high expression of PDE3 and PDE4 isoforms in endothelial cells. Treatment of endothelial cells with PDE3/4 inhibitor significantly decreased ADMA-induced apoptosis via a cAMP/PKA-dependent pathway by induction of DDAH2. Chronic nebulization of PDE3/4 inhibitor significantly attenuated monocrotaline-induced hemodynamic, gas exchange abnormalities, vascular remodeling, and right heart hypertrophy. Interestingly, PDE3/4 inhibitor treatment reduced ADMA and elevated nitric oxide/cGMP levels. Mechanistically, this could be attributed to direct modulatory effects of cAMP on the promoter region of DDAH2, which was consequently found to be increased in expression and activity. Furthermore, PDE3/4 inhibitor suppressed apoptosis in endothelial cells and increased vascularization in the lung. CONCLUSION Combined inhibition of PDE3 and 4 regresses development of pulmonary hypertension and promotes endothelial regeneration by modulating the ADMA-DDAH axis.
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Affiliation(s)
- Soni Savai Pullamsetti
- Max-Planck-Institute for Heart and Lung Research, Parkstrasse 1, 61231 Bad Nauheim, Germany
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Zhang P, Hu X, Xu X, Chen Y, Bache RJ. Dimethylarginine dimethylaminohydrolase 1 modulates endothelial cell growth through nitric oxide and Akt. Arterioscler Thromb Vasc Biol 2011; 31:890-7. [PMID: 21212404 DOI: 10.1161/atvbaha.110.215640] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
OBJECTIVE Dimethylarginine dimethylaminohydrolase 1 (DDAH1) modulates NO production by degrading the endogenous nitric oxide (NO) synthase (NOS) inhibitors asymmetrical dimethylarginine (ADMA) and L-NG-monomethyl arginine (L-NMMA). This study examined whether, in addition to degrading ADMA, DDAH1 exerts ADMA-independent effects that influence endothelial function. METHODS AND RESULTS Using selective gene silencing of DDAH1 with small interfering RNA and overexpression of DDAH1 in human umbilical vein endothelial cells, we found that DDAH1 acts to promote endothelial cell proliferation, migration, and tube formation by Akt phosphorylation, as well as through the traditional role of degrading ADMA. Incubation of human umbilical vein endothelial cells with the NOS inhibitors l-NG-nitro-arginine methyl ester (L-NAME) or ADMA, the soluble guanylyl cyclase inhibitor 1H-(1,2,4)oxadiazolo-(4,3-2)quinoxalin-1-one, or the cGMP analog 8-(4-Chlorophenylthio)-cGMP had no effect on phosphorylated (p)-Akt(Ser473), indicating that the increase in p-Akt(Ser473) produced by DDAH1 was independent of the NO-cGMP signaling pathway. DDAH1 formed a protein complex with Ras, and DDAH1 overexpression increased Ras activity. The Ras inhibitor manumycin-A or dominant-negative Ras significantly attenuated the DDAH1-induced increase in p-Akt(Ser473). Furthermore, DDAH1 knockout impaired endothelial sprouting from cultured aortic rings, and overexpression of constitutively active Akt or DDAH1 rescued endothelial sprouting in the aortic rings from these mice. CONCLUSIONS DDAH1 exerts a unique role in activating Akt that affects endothelial function independently of degrading endogenous NOS inhibitors.
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Affiliation(s)
- Ping Zhang
- Division of Cardiology, University of Minnesota Medical School, Minneapolis, MN 55455, USA
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Kaleem A, Ahmad I, Walker-Nasir E, Hoessli DC, Shakoori AR. Effect on the Ras/Raf signaling pathway of post-translational modifications of neurofibromin: in silico study of protein modification responsible for regulatory pathways. J Cell Biochem 2010; 108:816-24. [PMID: 19718661 DOI: 10.1002/jcb.22301] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Mapping and chemical characterization of post-translational modifications (PTMs) in proteins are critical to understand the regulatory mechanisms involving modified proteins and their role in disease. Neurofibromatosis type 1 (NF-1) is an autosomal dominantly inherited disorder, where NF1 mutations usually result in a reduced level of the tumor suppressor protein, neurofibromin (NF). NF is a multifunctional cytoplasmic protein that regulates microtubule dynamics and participates in several signaling pathways, particularly the RAS signaling pathway. NF is a Ras GTPase-activating protein (GAP) that prevents oncogenesis by converting GTP-Ras to GDP-Ras. This function of NF is regulated by phosphorylation. Interplay of phosphorylation with O-GlcNAc modification on the same or vicinal Ser/Thr residues, the Yin Yang sites, is well known in cytoplasmic and nuclear proteins. The dynamic aspects of PTMs and their interplay being difficult to follow in vivo, we undertook this in silico work to predict and define the possible role of Yin Yang sites in NF-1. Interplay of phosphorylation and O-GlcNAc modification is proposed as a mechanism controlling the Ras signaling pathway.
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Affiliation(s)
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- Institute of Molecular Sciences and Bioinformatics, Lahore, Pakistan.
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Rodionov RN, Dayoub H, Lynch CM, Wilson KM, Stevens JW, Murry DJ, Kimoto M, Arning E, Bottiglieri T, Cooke JP, Baumbach GL, Faraci FM, Lentz SR. Overexpression of dimethylarginine dimethylaminohydrolase protects against cerebral vascular effects of hyperhomocysteinemia. Circ Res 2009; 106:551-8. [PMID: 20019334 DOI: 10.1161/circresaha.109.200360] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
RATIONALE Hyperhomocysteinemia is a cardiovascular risk factor that is associated with elevation of the nitric oxide synthase inhibitor asymmetrical dimethylarginine (ADMA). OBJECTIVE Using mice transgenic for overexpression of the ADMA-hydrolyzing enzyme dimethylarginine dimethylaminohydrolase-1 (DDAH1), we tested the hypothesis that overexpression of DDAH1 protects from adverse structural and functional changes in cerebral arterioles in hyperhomocysteinemia. METHODS AND RESULTS Hyperhomocysteinemia was induced in DDAH1 transgenic (DDAH1 Tg) mice and wild-type littermates using a high methionine/low folate (HM/LF) diet. Plasma total homocysteine was elevated approximately 3-fold in both wild-type and DDAH1 Tg mice fed the HM/LF diet compared with the control diet (P<0.001). Plasma ADMA was approximately 40% lower in DDAH1 Tg mice compared with wild-type mice (P<0.001) irrespective of diet. Compared with the control diet, the HM/LF diet diminished endothelium-dependent dilation to 10 micromol/L acetylcholine in cerebral arterioles of both wild-type (12 + or - 2 versus 29 + or - 3%; P<0.001) and DDAH1 Tg (14 + or - 3 versus 28 + or - 2%; P<0.001) mice. Responses to 10 micromol/L papaverine, a direct smooth muscle dilator, were impaired with the HM/LF diet in wild-type mice (30 + or - 3 versus 45 + or - 5%; P<0.05) but not DDAH1 Tg mice (45 + or - 7 versus 48 + or - 6%). DDAH1 Tg mice also were protected from hypertrophy of cerebral arterioles (P<0.05) but not from accelerated carotid artery thrombosis induced by the HM/LF diet. CONCLUSIONS Overexpression of DDAH1 protects from hyperhomocysteinemia-induced alterations in cerebral arteriolar structure and vascular muscle function.
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Affiliation(s)
- Roman N Rodionov
- Department of Internal Medicine, C32 GH, The University of Iowa, Iowa City, IA 52242, USA
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Maas R, Böger R, Lüneburg N. ADMA and the role of the genes: lessons from genetically modified animals and human gene polymorphisms. Pharmacol Res 2009; 60:475-80. [PMID: 19666122 DOI: 10.1016/j.phrs.2009.07.012] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/09/2009] [Revised: 07/30/2009] [Accepted: 07/31/2009] [Indexed: 10/20/2022]
Abstract
In large population-based cohorts, elevated plasma levels of asymmetric dimethylarginine (ADMA) were found to be associated with cardiovascular events and mortality. Impairment of nitric oxide (NO) synthesis from l-arginine has been postulated as underlying mechanism. In the present review, we compare different experimental models of NOS deficiency or overexpression with corresponding models of altered metabolism of ADMA by dimethylarginine dimethylaminohydrolase (DDAH). The latter models show a considerable overlap with the pathophysiological features of impaired NO synthesis, such as impaired endothelial function, elevation of blood pressure, and microvascular fibrosis. In line with these findings, first data regarding genetic variation of DDAH-metabolism in humans are reminiscent of the (rather modest) effects previously observed with polymorphisms of the eNOS gene. However, several peculiar observations suggest that ADMA- or DDAH-related pathology may extend beyond impairment of NO-mediated signalling. Notably, the complete knock out of DDAH1 appears to be lethal while triple NOS(-/-) mice are viable. Moreover, some ADMA-mediated pathology appears to respond rather to ACE-inhibition than to l-arginine. Here, a further investigation of alternative target enzymes for ADMA and other endogenous DDAH substrates is warranted.Taken together, the current data suggest that ADMA-related pathology can largely but not completely be explained by impaired NO metabolism.
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Affiliation(s)
- Renke Maas
- Institute of Experimental and Clinical Pharmacology and Toxicology, Friedrich-Alexander University, Erlangen-Nuremberg, Germany.
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Jones GN, Tep C, Towns WH 2nd, Mihai G, Tonks ID, Kay GF, Schmalbrock PM, Stemmer-Rachamimov AO, Yoon SO, Kirschner LS. Tissue-specific ablation of Prkar1a causes schwannomas by suppressing neurofibromatosis protein production. Neoplasia 2008; 10:1213-21. [PMID: 18953430 DOI: 10.1593/neo.08652] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2008] [Revised: 07/23/2008] [Accepted: 07/29/2008] [Indexed: 11/18/2022] Open
Abstract
Signaling events leading to Schwann cell tumor initiation have been extensively characterized in the context of neurofibromatosis (NF). Similar tumors are also observed in patients with the endocrine neoplasia syndrome Carney complex, which results from inactivating mutations in PRKAR1A. Loss of PRKAR1A causes enhanced protein kinase A activity, although the pathways leading to tumorigenesis are not well characterized. Tissue-specific ablation of Prkar1a in neural crest precursor cells (TEC3KO mice) causes schwannomas with nearly 80% penetrance by 10 months. These heterogeneous neoplasms were clinically characterized as genetically engineered mouse schwannomas, grades II and III. At the molecular level, analysis of the tumors revealed almost complete loss of both NF proteins, despite the fact that transcript levels were increased, implying posttranscriptional regulation. Although Erk and Akt signaling are typically enhanced in NF-associated tumors, we observed no activation of either of these pathways in TEC3KO tumors. Furthermore, the small G proteins Ras, Rac1, and RhoA are all known to be involved with NF signaling. In TEC3KO tumors, all three molecules showed modest increases in total protein, but only Rac1 showed significant activation. These data suggest that dysregulated protein kinase A activation causes tumorigenesis through pathways that overlap but are distinct from those described in NF tumorigenesis.
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Patrakitkomjorn S, Kobayashi D, Morikawa T, Wilson MM, Tsubota N, Irie A, Ozawa T, Aoki M, Arimura N, Kaibuchi K, Saya H, Araki N. Neurofibromatosis Type 1 (NF1) Tumor Suppressor, Neurofibromin, Regulates the Neuronal Differentiation of PC12 Cells via Its Associating Protein, CRMP-2. J Biol Chem 2008; 283:9399-413. [DOI: 10.1074/jbc.m708206200] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
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Palm F, Onozato ML, Luo Z, Wilcox CS. Dimethylarginine dimethylaminohydrolase (DDAH): expression, regulation, and function in the cardiovascular and renal systems. Am J Physiol Heart Circ Physiol 2007; 293:H3227-45. [PMID: 17933965 DOI: 10.1152/ajpheart.00998.2007] [Citation(s) in RCA: 244] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Asymmetric (N(G),N(G))-dimethylarginine (ADMA) inhibits nitric oxide (NO) synthases (NOS). ADMA is a risk factor for endothelial dysfunction, cardiovascular mortality, and progression of chronic kidney disease. Two isoforms of dimethylarginine dimethylaminohydrolase (DDAH) metabolize ADMA. DDAH-1 is the predominant isoform in the proximal tubules of the kidney and in the liver. These organs extract ADMA from the circulation. DDAH-2 is the predominant isoform in the vasculature, where it is found in endothelial cells adjacent to the cell membrane and in intracellular vesicles and in vascular smooth muscle cells among the myofibrils and the nuclear envelope. In vivo gene silencing of DDAH-1 in the rat and DDAH +/- mice both have increased circulating ADMA, whereas gene silencing of DDAH-2 reduces vascular NO generation and endothelium-derived relaxation factor responses. DDAH-2 also is expressed in the kidney in the macula densa and distal nephron. Angiotensin type 1 receptor activation in kidneys reduces the expression of DDAH-1 but increases the expression of DDAH-2. This rapidly evolving evidence of isoform-specific distribution and regulation of DDAH expression in the kidney and blood vessels provides potential mechanisms for nephron site-specific regulation of NO production. In this review, the recent advances in the regulation and function of DDAH enzymes, their roles in the regulation of NO generation, and their possible contribution to endothelial dysfunction in patients with cardiovascular and kidney diseases are discussed.
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Affiliation(s)
- Fredrik Palm
- Division of Nephrology and Hypertension, Georgetown University, 3800 Reservoir Road N.W., Washington, DC 20007, USA
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Welti S, Fraterman S, D'Angelo I, Wilm M, Scheffzek K. The sec14 homology module of neurofibromin binds cellular glycerophospholipids: mass spectrometry and structure of a lipid complex. J Mol Biol 2006; 366:551-62. [PMID: 17187824 DOI: 10.1016/j.jmb.2006.11.055] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2006] [Revised: 11/12/2006] [Accepted: 11/15/2006] [Indexed: 11/30/2022]
Abstract
Neurofibromin is the protein product of the tumor suppressor gene NF1, alterations of which are responsible for the pathogenesis of the common disorder Neurofibromatosis type I (NF1). The only well-characterized function of neurofibromin is its RasGAP activity, contained in the central GAP related domain (GRD). By solving the crystal structure of a 31 kDa fragment at the C-terminal end of the GRD we have recently identified a novel bipartite lipid-binding module composed of a Sec14 homologous and a previously undetected pleckstrin homology (PH)-like domain. Using lipid exchange assays along with mass spectrometry we show here that the Sec14-like portion binds to 1-(3-sn-phosphatidyl)-sn-glycerol (PtdGro), (3-sn-phosphatidyl)-ethanolamine (PtdEtn) and -choline (PtdCho) and to a minor extent to (3-sn-phosphatidyl)-l-serine (PtdSer) and 1-(3-sn-phosphatidyl)-d-myo-inositol (PtdIns). Phosphorylated PtdIns (PtdInsPs) are not detected as binders in the mass spectrometry assay, but their soluble inositol-phosphate headgroups and related compounds can inhibit the lipid exchange reaction. We also present here the crystal structure of this module with the Sec14 portion bound to a cellular glycerophospholipid ligand. Our structure has model character for the substrate-bound form of yeast Sec14p, of which only detergent bound structures are available so far. To assess potential regulation of the lipid exchange reaction in detail, we present a novel strategy using nanospray mass spectrometry. Ion intensities of initial phospholipids and exchanged deuterated analogues bound by the protein module allow the quantitative analysis of differences in the exchange activity under various conditions.
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Affiliation(s)
- Stefan Welti
- Structural and Computational Biology, Developmental Biology and Gene Expression Units, European Molecular Biology Laboratory, Meyerhofstrasse 1, 69117 Heidelberg, Germany
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Abstract
Neurofibromin is a cytoplasmic protein that is predominantly expressed in neurons, Schwann cells, oligodendrocytes, astrocytes and leukocytes. It is encoded by the gene NF1, located on chromosome 17, at q11.2, and has different biochemical functions, including association to microtubules and participation in several signaling pathways. Alterations in this protein are responsible for a phacomatosis named neurofibromatosis type 1.
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Affiliation(s)
- A B Trovó-Marqui
- Departamento de Biologia, UNESP-Universidade Estadual Paulista, Brazil
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Leiper J, Vallance P. New tricks from an old dog: nitric oxide-independent effects of dimethylarginine dimethylaminohydrolase. Arterioscler Thromb Vasc Biol 2006; 26:1419-20. [PMID: 16794231 DOI: 10.1161/01.atv.0000229598.55602.17] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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36
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D'angelo I, Welti S, Bonneau F, Scheffzek K. A novel bipartite phospholipid-binding module in the neurofibromatosis type 1 protein. EMBO Rep 2006; 7:174-9. [PMID: 16397625 PMCID: PMC1369252 DOI: 10.1038/sj.embor.7400602] [Citation(s) in RCA: 97] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2005] [Revised: 11/08/2005] [Accepted: 11/10/2005] [Indexed: 11/09/2022] Open
Abstract
Neurofibromatosis type 1 (NF1) is a common tumour predisposition syndrome associated with numerous clinical complications. Mutations in the tumour suppressor gene NF1 are responsible for disease pathogenesis. This gene encodes the 320 kDa protein neurofibromin, the only clearly defined function of which is to act as a Ras-specific GTPase-activating protein (RasGAP). Here we report the structural discovery of a novel module in neurofibromin, composed of a Sec14p homologous segment and a previously undetected pleckstrin homology (PH)-like domain of potentially novel function. We show phospholipid binding by this bipartite module and identify residues that are involved in this activity; we also show that the PH-like domain is not sufficient for lipid binding. The unique architecture of the domain interface points to a model of how the PH-like domain may regulate binding of a ligand by the Sec14 module.
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Affiliation(s)
- Igor D'angelo
- European Molecular Biology Laboratory, Structural and Computational Biology Programme, Meyerhofstrasse 1, 69117 Heidelberg, Germany
| | - Stefan Welti
- European Molecular Biology Laboratory, Structural and Computational Biology Programme, Meyerhofstrasse 1, 69117 Heidelberg, Germany
| | - Fabien Bonneau
- European Molecular Biology Laboratory, Structural and Computational Biology Programme, Meyerhofstrasse 1, 69117 Heidelberg, Germany
| | - Klaus Scheffzek
- European Molecular Biology Laboratory, Structural and Computational Biology Programme, Meyerhofstrasse 1, 69117 Heidelberg, Germany
- Tel: +49 6221 387 401; Fax: +49 6221 387 519; E-mail:
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Hasegawa K, Wakino S, Tanaka T, Kimoto M, Tatematsu S, Kanda T, Yoshioka K, Homma K, Sugano N, Kurabayashi M, Saruta T, Hayashi K. Dimethylarginine dimethylaminohydrolase 2 increases vascular endothelial growth factor expression through Sp1 transcription factor in endothelial cells. Arterioscler Thromb Vasc Biol 2006; 26:1488-94. [PMID: 16574895 DOI: 10.1161/01.atv.0000219615.88323.b4] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
OBJECTIVE Dimethylarginie dimethylaminohydrolase (DDAH) is a degrading enzyme for asymmetrical dimethylarginine, an endogenous NO synthase inhibitor. The molecular mechanism for DDAH-induced vascular endothelial growth factor (VEGF) expression was examined. METHODS AND RESULTS Although the transfection of expression vectors for 2 isoforms of DDAH, DDAH1, or DDAH2 increased DDAH activity in bovine aortic endothelial cells and human umbilical vein endothelial cells, expression and secretion of VEGF were increased only in DDAH2-transfected cells. Knocking down the DDAH2 gene reduced VEGF production, and DDAH2 overexpression enhanced both proliferation and migration of endothelial cells. The VEGF promoter activity was increased by DDAH2 transfection, which was not blocked by an NO synthase (NOS) inhibitor but required the Sp1 sites. DDAH2 overexpression increased nuclear protein levels bound to Sp1 oligonucleotides in endothelial cells. Sp1 small interfering RNA blocked DDAH2-induced upregulation of VEGF. DDAH2 transfection increased nuclear and threonine-phosphorylation levels of Sp1 in a protein kinase A (PKA)-dependent manner. Protein-protein interaction between DDAH2 and PKA was enhanced in DDAH2-transfected cells. CONCLUSIONS DDAH2 upregulated the expression of VEGF through Sp1-dependent and NO/NOS system-independent promoter activation. DDAH2-increased Sp1 DNA binding activity was PKA dependent. These mechanisms may provide a novel therapeutic strategy for VEGF-related vasculopathies such as atherosclerosis.
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Affiliation(s)
- Kazuhiro Hasegawa
- Department of Internal Medicine, Keio University, 35 Shinanomachi, Shinjuku-ku, Tokyo, Japan
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Abstract
Circadian oscillators in chicken cone photoreceptors regulate the gating properties of cGMP-gated cationic channels (CNGCs) such that they have a higher apparent affinity for cGMP during the subjective night. Here we show that cAMP, acting through protein kinase A (PKA), Ras, and Erk, is part of the circadian output pathway controlling CNGCs. Endogenous and exogenous cAMP cause activation of Erk and Ras, which are more active at night in cones, and increase the apparent affinity of CNGCs for cGMP. The Ras farnesyl transferase inhibitor manumycin-A, and a dominant-negative form of Ras (RasN17) block the circadian rhythms in CNGC gating, as well as the effects of cAMP. A dominant-negative form of the MEK kinase B-Raf also blocks circadian and cAMP modulation of CNGCs. The circadian output pathway modulating CNGC channels is comprised in part of cAMP --> PKA --> Ras --> B-Raf --> MEK --> Erk --> --> CNGCs. cAMP activation of Ras and Erk occur within minutes, whereas modulation of CNGCs requires >1 hr. However, cAMP protagonists do not alter rhythms in cPer2 mRNA, and their effects on CNGCs cannot be attributed to clock phase-shifting.
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Affiliation(s)
- Gladys Y-P Ko
- Department of Biology and Biochemistry and Biological Clocks Program, University of Houston, Houston, Texas 77204-5001, USA
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Feng L, Yunoue S, Tokuo H, Ozawa T, Zhang D, Patrakitkomjorn S, Ichimura T, Saya H, Araki N. PKA phosphorylation and 14-3-3 interaction regulate the function of neurofibromatosis type I tumor suppressor, neurofibromin. FEBS Lett 2003; 557:275-82. [PMID: 14741381 DOI: 10.1016/s0014-5793(03)01507-2] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Neurofibromin, a neurofibromatosis type I (NF1) tumor suppressor gene product, has a domain acting as a GTPase activating protein and functions in part as a negative regulator of Ras. Loss of neurofibromin expression in NF1 patients is associated with elevated Ras activity and increased cell proliferation. Therefore, regulation of the function of neurofibromin is heavily involved in cell growth and differentiation. In the present study, we identified a novel cellular neurofibromin-associating protein, 14-3-3, which belongs to a highly conserved family of proteins that regulate intracellular signal transduction events in all eukaryotic cells. The interaction of 14-3-3 is mainly directed to the C-terminal domain (CTD) of neurofibromin, and the cAMP-dependent protein kinase (PKA)-dependent phosphorylation clustered on CTD-Ser (2576, 2578, 2580, 2813) and Thr (2556) is required for the interaction. Interestingly, the increased phosphorylation and association of 14-3-3 negatively regulate the function of neurofibromin. These findings indicate that PKA phosphorylation followed by 14-3-3 protein interaction may modulate the biochemical and biological functions of neurofibromin.
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Affiliation(s)
- Liping Feng
- Department of Tumor Genetics and Biology, Graduate School of Medical Sciences, Kumamoto University, 1-1-1 Honjo, Kumamoto 860-8556, Japan
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Yunoue S, Tokuo H, Fukunaga K, Feng L, Ozawa T, Nishi T, Kikuchi A, Hattori S, Kuratsu J, Saya H, Araki N. Neurofibromatosis type I tumor suppressor neurofibromin regulates neuronal differentiation via its GTPase-activating protein function toward Ras. J Biol Chem 2003; 278:26958-69. [PMID: 12730209 DOI: 10.1074/jbc.m209413200] [Citation(s) in RCA: 74] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Neurofibromin, the neurofibromatosis type 1 (NF1) gene product, contains a central domain homologous to a family of proteins known as Ras-GTPase-activating proteins (Ras-GAPs), which function as negative regulators of Ras. The loss of neurofibromin function has been thought to be implicated in the abnormal regulation of Ras in NF1-related pathogenesis. In this study, we found a novel role of neurofibromin in neuronal differentiation in conjunction with the regulation of Ras activity via its GAP-related domain (GRD) in neuronal cells. In PC12 cells, time-dependent increases in the GAP activity of cellular neurofibromin (NF1-GAP) were detected after NGF stimulation, which were correlated with the down-regulation of Ras activity during neurite elongation. Interestingly, the NF1-GAP increase was due to the induction of alternative splicing of NF1-GRD type I triggered by the NGF-induced Ras activation. Dominant-negative (DN) forms of NF1-GRD type I significantly inhibited the neurite extension of PC12 cells via regulation of the Ras state. NF1-GRD-DN also reduced axonal and dendritic branching/extension of rat embryonic hippocampal neurons. These results demonstrate that the mutual regulation of Ras and NF1-GAP is essential for normal neuronal differentiation and that abnormal regulation in neuronal cells may be implicated in NF1-related learning and memory disturbance.
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Affiliation(s)
- Shunji Yunoue
- Department of Tumor Genetics and Biology, Kumamoto University School of Medicine, Kumamoto 860-0811, Japan
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Kaufmann D, Müller R, Kenner O, Leistner W, Hein C, Vogel W, Bartelt B. The N-terminal splice product NF1-10a-2 of the NF1 gene codes for a transmembrane segment. Biochem Biophys Res Commun 2002; 294:496-503. [PMID: 12051738 DOI: 10.1016/s0006-291x(02)00501-6] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
One important function of the neurofibromatosis type 1 (NF1) product neurofibromin is the negative regulation of Ras activity on the cell membrane. Here, we describe an alternative splice product of the N-terminus of the NF1 gene. In this splice product, termed NF1-10a-2, the 45 bp exon 10a-2 is inserted between exons 10a and 10b. Amino acid sequence analysis for motifs showed that the new splice product contains a transmembrane segment not found in wild-type neurofibromin. The overall expression was found to be very low in comparison to the expression of the wild-type mRNA in all human primary and tumor cells examined. Because transcripts were found in the majority of human tissues examined, we assume a housekeeping function of this splice product. Investigation of the intracellular localization of an NF1-10a-2-EGFP fusion protein in HeLa cells revealed a preferential localization in perinuclear granular structures. We therefore assume that NF1-10a-2 has a function on an intracellular membrane.
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Affiliation(s)
- Dieter Kaufmann
- Department of Human Genetics, University of Ulm, Albert-Einstein-Alle 11, Ulm D 89070, Germany.
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