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Montag K, Ivanov R, Bauer P. Role of SEC14-like phosphatidylinositol transfer proteins in membrane identity and dynamics. FRONTIERS IN PLANT SCIENCE 2023; 14:1181031. [PMID: 37255567 PMCID: PMC10225987 DOI: 10.3389/fpls.2023.1181031] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/06/2023] [Accepted: 04/05/2023] [Indexed: 06/01/2023]
Abstract
Membrane identity and dynamic processes, that act at membrane sites, provide important cues for regulating transport, signal transduction and communication across membranes. There are still numerous open questions as to how membrane identity changes and the dynamic processes acting at the surface of membranes are regulated in diverse eukaryotes in particular plants and which roles are being played by protein interaction complexes composed of peripheral and integral membrane proteins. One class of peripheral membrane proteins conserved across eukaryotes comprises the SEC14-like phosphatidylinositol transfer proteins (SEC14L-PITPs). These proteins share a SEC14 domain that contributes to membrane identity and fulfills regulatory functions in membrane trafficking by its ability to sense, bind, transport and exchange lipophilic substances between membranes, such as phosphoinositides and diverse other lipophilic substances. SEC14L-PITPs can occur as single-domain SEC14-only proteins in all investigated organisms or with a modular domain structure as multi-domain proteins in animals and streptophytes (comprising charales and land plants). Here, we present an overview on the functional roles of SEC14L-PITPs, with a special focus on the multi-domain SEC14L-PITPs of the SEC14-nodulin and SEC14-GOLD group (PATELLINs, PATLs in plants). This indicates that SEC14L-PITPs play diverse roles from membrane trafficking to organism fitness in plants. We concentrate on the structure of SEC14L-PITPs, their ability to not only bind phospholipids but also other lipophilic ligands, and their ability to regulate complex cellular responses through interacting with proteins at membrane sites.
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Affiliation(s)
- Karolin Montag
- Institute of Botany, Heinrich Heine University, Düsseldorf, Germany
| | - Rumen Ivanov
- Institute of Botany, Heinrich Heine University, Düsseldorf, Germany
| | - Petra Bauer
- Institute of Botany, Heinrich Heine University, Düsseldorf, Germany
- Center of Excellence on Plant Sciences (CEPLAS), Germany
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2
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Selvapandiyan A, Puri N, Kumar P, Alam A, Ehtesham NZ, Griffin G, Hasnain SE. Zooming in on common immune evasion mechanisms of pathogens in phagolysosomes: potential broad-spectrum therapeutic targets against infectious diseases. FEMS Microbiol Rev 2023; 47:6780197. [PMID: 36309472 DOI: 10.1093/femsre/fuac041] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2022] [Revised: 10/06/2022] [Accepted: 10/18/2022] [Indexed: 01/19/2023] Open
Abstract
The intracellular viral, bacterial, or parasitic pathogens evade the host immune challenges to propagate and cause fatal diseases. The microbes overpower host immunity at various levels including during entry into host cells, phagosome formation, phagosome maturation, phagosome-lysosome fusion forming phagolysosomes, acidification of phagolysosomes, and at times after escape into the cytosol. Phagolysosome is the final organelle in the phagocyte with sophisticated mechanisms to degrade the pathogens. The immune evasion strategies by the pathogens include the arrest of host cell apoptosis, decrease in reactive oxygen species, the elevation of Th2 anti-inflammatory response, avoidance of autophagy and antigen cross-presentation pathways, and escape from phagolysosomal killing. Since the phagolysosome organelle in relation to infection/cure is seldom discussed in the literature, we summarize here the common host as well as pathogen targets manipulated or utilized by the pathogens established in phagosomes and phagolysosomes, to hijack the host immune system for their benefit. These common molecules or pathways can be broad-spectrum therapeutic targets for drug development for intervention against infectious diseases caused by different intracellular pathogens.
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Affiliation(s)
| | - Niti Puri
- Cellular and Molecular Immunology Laboratory, School of Life Sciences, Jawaharlal Nehru University, New Delhi, 110067, India
| | - Pankaj Kumar
- Department of Biochemistry, Jamia Hamdard, New Delhi, 110062, India.,Centre for Tuberculosis Research, Department of Medicine, Johns Hopkins University, Baltimore, MD, 21218, United States
| | - Anwar Alam
- ICMR-National Institute of Pathology, Safdarjung Hospital Campus, New Delhi, 110029, India.,Department of Biochemical Engineering and Biotechnology, Indian Institute of Technology-Delhi, New Delhi, 110016, India
| | - Nasreen Zafar Ehtesham
- ICMR-National Institute of Pathology, Safdarjung Hospital Campus, New Delhi, 110029, India
| | - George Griffin
- Department of Cellular and Molecular Medicine, St. George's University of London, London, SW17 0RE, United Kingdom
| | - Seyed Ehtesham Hasnain
- Department of Biochemical Engineering and Biotechnology, Indian Institute of Technology-Delhi, New Delhi, 110016, India.,Department of Life Science, School of Basic Sciences and Research, Sharda University, Knowledge Park III, Greater Noida, 201310, India
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3
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Watt AT, Head B, Leonard SW, Tanguay RL, Traber MG. Gene Expression of CRAL_TRIO Family Proteins modulated by Vitamin E Deficiency in Zebrafish (Danio Rerio). J Nutr Biochem 2021; 97:108801. [PMID: 34119630 PMCID: PMC10129037 DOI: 10.1016/j.jnutbio.2021.108801] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2020] [Revised: 04/19/2021] [Accepted: 06/01/2021] [Indexed: 11/15/2022]
Abstract
An evaluation of the impact of vitamin E deficiency on expression of the alpha-tocopherol transfer protein (α-TTP) and related CRAL_TRIO genes was undertaken using livers from adult zebrafish based on the hypothesis that increased lipid peroxidation would modulate gene expression. Zebrafish were fed either a vitamin E sufficient (E+) or deficient (E-) diet for 9 months, then fish were euthanized, and livers were harvested. Livers from the E+ relative to E- fish contained 40-times more α-tocopherol (P <0.0001) and one fourth the malondialdehyde (P = 0.0153). RNA was extracted from E+ and E- livers, then subject to evaluation of gene expression of ttpa and other genes of the CRAL_TRIO family, genes of antioxidant markers, and genes related to lipid metabolism. Ttpa expression was not altered by vitamin E status. However, one member of the CRAL_TRIO family, tyrosine-protein phosphatase non-receptor type 9 gene (ptpn9a), showed a 2.4-fold increase (P = 0.029) in E- relative to E+ livers. Further, we identified that the gene for choline kinase alpha (chka) showed a 3.0-fold increase (P = 0.010) in E- livers. These outcomes are consistent with our previous findings that show vitamin E deficiency increased lipid peroxidation causing increases in phospholipid turnover.
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Affiliation(s)
- Alexander T Watt
- Linus Pauling Institute, Oregon State University, Corvallis, Oregon; Integrative Biology Program, Oregon State University, Corvallis, Oregon
| | - Brian Head
- Linus Pauling Institute, Oregon State University, Corvallis, Oregon; Molecular and Cell Biology Program
| | - Scott W Leonard
- Linus Pauling Institute, Oregon State University, Corvallis, Oregon
| | - Robyn L Tanguay
- Department of Environmental and Molecular Toxicology, Oregon State University, Corvallis, Oregon
| | - Maret G Traber
- Linus Pauling Institute, Oregon State University, Corvallis, Oregon; School of Biological and Population Health Sciences, Oregon State University, Corvallis, Oregon.
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4
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Lete MG, Tripathi A, Chandran V, Bankaitis VA, McDermott MI. Lipid transfer proteins and instructive regulation of lipid kinase activities: Implications for inositol lipid signaling and disease. Adv Biol Regul 2020; 78:100740. [PMID: 32992233 PMCID: PMC7986245 DOI: 10.1016/j.jbior.2020.100740] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2020] [Revised: 06/16/2020] [Accepted: 06/24/2020] [Indexed: 05/17/2023]
Abstract
Cellular membranes are critical platforms for intracellular signaling that involve complex interfaces between lipids and proteins, and a web of interactions between a multitude of lipid metabolic pathways. Membrane lipids impart structural and functional information in this regulatory circuit that encompass biophysical parameters such as membrane thickness and fluidity, as well as chaperoning the interactions of protein binding partners. Phosphatidylinositol and its phosphorylated derivatives, the phosphoinositides, play key roles in intracellular membrane signaling, and these involvements are translated into an impressively diverse set of biological outcomes. The phosphatidylinositol transfer proteins (PITPs) are key regulators of phosphoinositide signaling. Found in a diverse array of organisms from plants, yeast and apicomplexan parasites to mammals, PITPs were initially proposed to be simple transporters of lipids between intracellular membranes. It now appears increasingly unlikely that the soluble versions of these proteins perform such functions within the cell. Rather, these serve to facilitate the activity of intrinsically biologically insufficient inositol lipid kinases and, in so doing, promote diversification of the biological outcomes of phosphoinositide signaling. The central engine for execution of such functions is the lipid exchange cycle that is a fundamental property of PITPs. How PITPs execute lipid exchange remains very poorly understood. Molecular dynamics simulation approaches are now providing the first atomistic insights into how PITPs, and potentially other lipid-exchange/transfer proteins, operate.
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Affiliation(s)
- Marta G Lete
- Department of Molecular and Cellular Medicine, Texas A&M Health Sciences Center, College Station, TX, 77843-1114, USA; Institute Biofisika (UPV/EHU, CSIC) and University of the Basque Country, Leioa, Spain
| | - Ashutosh Tripathi
- Department of Molecular and Cellular Medicine, Texas A&M Health Sciences Center, College Station, TX, 77843-1114, USA
| | - Vijay Chandran
- Department of Molecular and Cellular Medicine, Texas A&M Health Sciences Center, College Station, TX, 77843-1114, USA
| | - Vytas A Bankaitis
- Department of Molecular and Cellular Medicine, Texas A&M Health Sciences Center, College Station, TX, 77843-1114, USA; Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX, 77843-2128, USA; Department of Chemistry, Texas A&M University, College Station, TX, 77840, USA
| | - Mark I McDermott
- Department of Molecular and Cellular Medicine, Texas A&M Health Sciences Center, College Station, TX, 77843-1114, USA.
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5
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Ma Y, Wei HY, Zhang YZ, Jin WY, Li HL, Zhou H, Cheng XC, Wang RL. Synthesis, bioactivity, 3D-QSAR studies of novel dibenzofuran derivatives as PTP-MEG2 inhibitors. Oncotarget 2018; 8:38466-38481. [PMID: 28388567 PMCID: PMC5503546 DOI: 10.18632/oncotarget.16595] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2017] [Accepted: 03/17/2017] [Indexed: 11/25/2022] Open
Abstract
PTP-MEG2 plays a critical role in the diverse cell signalling processes, so targeting PTP-MEG2 is a promising strategy for various human diseases treatments. In this study, a series of novel dibenzofuran derivatives was synthesized and assayed for their PTP-MEG2 inhibitory activities. 10a with highest inhibitory activity (320 nM) exhibited significant selectivity for PTP-MEG2 over its close homolog SHP2, CDC25 (IC50 > 50 μM). By means of the powerful “HipHop” technique, a 3D-QSAR study was carried out to explore structure activity relationship of these molecules. The generated pharmacophore model revealed that the one RA, three Hyd, and two HBA features play an important role in binding to the active site of the target protein-PTP-MEG2. Docking simulation study indicated that 10a achieved its potency and specificity for PTP-MEG2 by targeting unique nearby peripheral binding pockets and the active site. The absorption, distribution, metabolism and excretion (ADME) predictions showed that the 11 compounds hold high potential to be novel lead compounds for targeting PTP-MEG2. Our findings here can provide a new strategy or useful insights for designing the effective PTP-MEG2 inhibitors.
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Affiliation(s)
- Ying Ma
- Tianjin Key Laboratory on Technologies Enabling Development of Clinical Therapeutics and Diagnostics (Theranostics), School of Pharmacy, Tianjin Medical University, Tianjin, China
| | - Hui-Yu Wei
- Tianjin Key Laboratory on Technologies Enabling Development of Clinical Therapeutics and Diagnostics (Theranostics), School of Pharmacy, Tianjin Medical University, Tianjin, China.,Eye Hospital, Tianjin Medical University, School of Optometry and Ophthalmology, Tianjin Medical University, Tianjin, China
| | - Yu-Ze Zhang
- Tianjin Key Laboratory on Technologies Enabling Development of Clinical Therapeutics and Diagnostics (Theranostics), School of Pharmacy, Tianjin Medical University, Tianjin, China
| | - Wen-Yan Jin
- Tianjin Key Laboratory on Technologies Enabling Development of Clinical Therapeutics and Diagnostics (Theranostics), School of Pharmacy, Tianjin Medical University, Tianjin, China
| | - Hong-Lian Li
- Tianjin Key Laboratory on Technologies Enabling Development of Clinical Therapeutics and Diagnostics (Theranostics), School of Pharmacy, Tianjin Medical University, Tianjin, China
| | - Hui Zhou
- Tianjin Key Laboratory on Technologies Enabling Development of Clinical Therapeutics and Diagnostics (Theranostics), School of Pharmacy, Tianjin Medical University, Tianjin, China
| | - Xian-Chao Cheng
- Tianjin Key Laboratory on Technologies Enabling Development of Clinical Therapeutics and Diagnostics (Theranostics), School of Pharmacy, Tianjin Medical University, Tianjin, China
| | - Run-Ling Wang
- Tianjin Key Laboratory on Technologies Enabling Development of Clinical Therapeutics and Diagnostics (Theranostics), School of Pharmacy, Tianjin Medical University, Tianjin, China
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6
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Huang Y, Zhang Y, Ge L, Lin Y, Kwok HF. The Roles of Protein Tyrosine Phosphatases in Hepatocellular Carcinoma. Cancers (Basel) 2018; 10:cancers10030082. [PMID: 29558404 PMCID: PMC5876657 DOI: 10.3390/cancers10030082] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2018] [Revised: 03/12/2018] [Accepted: 03/15/2018] [Indexed: 02/08/2023] Open
Abstract
The protein tyrosine phosphatase (PTP) family is involved in multiple cellular functions and plays an important role in various pathological and physiological processes. In many chronic diseases, for example cancer, PTP is a potential therapeutic target for cancer treatment. In the last two decades, dozens of PTP inhibitors which specifically target individual PTP molecules were developed as therapeutic agents. Hepatocellular carcinoma (HCC) is one of the most common malignant tumors and is the second most lethal cancer worldwide due to a lack of effective therapies. Recent studies have unveiled both oncogenic and tumor suppressive functions of PTP in HCC. Here, we review the current knowledge on the involvement of PTP in HCC and further discuss the possibility of targeting PTP in HCC.
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Affiliation(s)
- Yide Huang
- Provincial University Key Laboratory of Cellular Stress Response and Metabolic Regulation, College of Life Sciences, Fujian Normal University, Fuzhou 350117, China.
- Faculty of Health Sciences, University of Macau, Avenida de Universidade, Taipa, Macau, China.
| | - Yafei Zhang
- Provincial University Key Laboratory of Cellular Stress Response and Metabolic Regulation, College of Life Sciences, Fujian Normal University, Fuzhou 350117, China.
| | - Lilin Ge
- Faculty of Health Sciences, University of Macau, Avenida de Universidade, Taipa, Macau, China.
- Jiangsu Key Laboratory for Functional Substance of Chinese Medicine, School of Pharmacy, Nanjing University of Chinese Medicine, Nanjing 210023, China.
| | - Yao Lin
- Provincial University Key Laboratory of Cellular Stress Response and Metabolic Regulation, College of Life Sciences, Fujian Normal University, Fuzhou 350117, China.
| | - Hang Fai Kwok
- Faculty of Health Sciences, University of Macau, Avenida de Universidade, Taipa, Macau, China.
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7
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Zhu J, Li H, Ma J, Huang H, Qin J, Li Y. PTPN9 promotes cell proliferation and invasion in Eca109 cells and is negatively regulated by microRNA-126. Oncol Lett 2017; 14:1419-1426. [PMID: 28789358 PMCID: PMC5529898 DOI: 10.3892/ol.2017.6315] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2015] [Accepted: 04/13/2017] [Indexed: 12/23/2022] Open
Abstract
Protein tyrosine phosphatase non-receptor type 9 (PTPN9), also named PTP-MEG2, is an important member of the protein tyrosine phosphatase family that is involved in variety of human diseases. However, the role of PTPN9 in esophageal squamous cell carcinoma (ESCC) remains to be established. The present evaluated the potential effect and underlying mechanism of action of PTPN9 in ESCC. Immunohistochemistry was performed to detect PTPN9 protein expression in 84 ESCC tumor specimens and 30 normal esophageal tissues. The association between positive expression of PTPN9 and clinicopathological features and prognosis was analyzed. The prognostic role of PTPN9 was further investigated using multivariate regression analysis. PTPN9-small interfering RNA and microRNA (miR-126)-mimics were transfected into Eca109 cells to construct PTPN9 silencing and an miR-126 ectopic expression cell model. Reverse transcription-quantitative polymerase chain reaction, western blot analysis, cell counting kit-8, Transwell assays and flow cytometry were used to investigate the role of PTPN9 in the process of ESCC progression and its potential downstream signaling pathway. Immunohistochemical analysis revealed that PTPN9 was upregulated in ESCC tumor specimens compared with normal esophageal tissues. The χ2 test indicated that positive expression of PTPN9 was correlated with tumor node metastasis stage, tumor classification and node classification. Patients with PTPN9 positive expression had shorter survival time, compared with those that were PTPN9 negative. Multivariate regression analysis with the Cox proportional hazards regression model revealed that PTPN9 expression was a prognostic factor of overall survival for patients with ESCC. Using RNA interference, the present study demonstrated that knockdown of PTPN9 significantly suppressed cell proliferation and invasion in Eca109. Additionally, it was hypothesized that miR-126, described as a tumor suppressor in ESCC, may act at least in part via its inhibition of PTPN9 at the post-transcriptional level. To the best of our knowledge, this is the first study to demonstrate that PTPN9 is overexpressed in ESCC and associated with poor survival, and may therefore be important in the pathogenesis of ESCC.
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Affiliation(s)
- Junwei Zhu
- Department of Thoracic Surgery, The Affiliated Tumor Hospital of Zhengzhou University, Zhengzhou, Henan 450008, P.R. China
| | - Haomiao Li
- Department of Thoracic Surgery, The Affiliated Tumor Hospital of Zhengzhou University, Zhengzhou, Henan 450008, P.R. China
| | - Jun Ma
- Department of Gastroenterology, The Second Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan 450014, P.R. China
| | - Haibo Huang
- Department of Thoracic Surgery, The Affiliated Tumor Hospital of Zhengzhou University, Zhengzhou, Henan 450008, P.R. China
| | - Jianjun Qin
- Department of Thoracic Surgery, The Affiliated Tumor Hospital of Zhengzhou University, Zhengzhou, Henan 450008, P.R. China
| | - Yin Li
- Department of Thoracic Surgery, The Affiliated Tumor Hospital of Zhengzhou University, Zhengzhou, Henan 450008, P.R. China
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8
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Zhang D, Marlin MC, Liang Z, Ahmad M, Ashpole NM, Sonntag WE, Zhao ZJ, Li G. The Protein Tyrosine Phosphatase MEG2 Regulates the Transport and Signal Transduction of Tropomyosin Receptor Kinase A. J Biol Chem 2016; 291:23895-23905. [PMID: 27655914 DOI: 10.1074/jbc.m116.728550] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2016] [Revised: 09/12/2016] [Indexed: 11/06/2022] Open
Abstract
Protein tyrosine phosphatase MEG2 (PTP-MEG2) is a unique nonreceptor tyrosine phosphatase associated with transport vesicles, where it facilitates membrane trafficking by dephosphorylation of the N-ethylmaleimide-sensitive fusion factor. In this study, we identify the neurotrophin receptor TrkA as a novel cargo whose transport to the cell surface requires PTP-MEG2 activity. In addition, TrkA is also a novel substrate of PTP-MEG2, which dephosphorylates both Tyr-490 and Tyr-674/Tyr-675 of TrkA. As a result, overexpression of PTP-MEG2 down-regulates NGF/TrkA signaling and blocks neurite outgrowth and differentiation in PC12 cells and cortical neurons.
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Affiliation(s)
- Dongmei Zhang
- From the Key Laboratory of Biopesticide and Chemical Biology, College of Plant Protection, Fujian Agriculture and Forestry University, 350002 Fuzhou, China.,the Departments of Biochemistry and Molecular Biology
| | | | - Zhimin Liang
- the Departments of Biochemistry and Molecular Biology
| | | | | | | | - Zhizhuang Joe Zhao
- Pathology.,Peggy and Charles Stephenson Cancer Center, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma 73104
| | - Guangpu Li
- the Departments of Biochemistry and Molecular Biology, .,Peggy and Charles Stephenson Cancer Center, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma 73104
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9
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Zhang S, Liu S, Tao R, Wei D, Chen L, Shen W, Yu ZH, Wang L, Jones DR, Dong XC, Zhang ZY. A highly selective and potent PTP-MEG2 inhibitor with therapeutic potential for type 2 diabetes. J Am Chem Soc 2012; 134:18116-24. [PMID: 23075115 DOI: 10.1021/ja308212y] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Protein tyrosine phosphatases (PTPs) constitute a large family of signaling enzymes that control the cellular levels of protein tyrosine phosphorylation. A detailed understanding of PTP functions in normal physiology and in pathogenic conditions has been hampered by the absence of PTP-specific, cell-permeable small-molecule agents. We present a stepwise focused library approach that transforms a weak and general non-hydrolyzable pTyr mimetic (F(2)Pmp, phosphonodifluoromethyl phenylalanine) into a highly potent and selective inhibitor of PTP-MEG2, an antagonist of hepatic insulin signaling. The crystal structures of the PTP-MEG2-inhibitor complexes provide direct evidence that potent and selective PTP inhibitors can be obtained by introducing molecular diversity into the F(2)Pmp scaffold to engage both the active site and unique nearby peripheral binding pockets. Importantly, the PTP-MEG2 inhibitor possesses highly efficacious cellular activity and is capable of augmenting insulin signaling and improving insulin sensitivity and glucose homeostasis in diet-induced obese mice. The results indicate that F(2)Pmp can be converted into highly potent and selective PTP inhibitory agents with excellent in vivo efficacy. Given the general nature of the approach, this strategy should be applicable to other members of the PTP superfamily.
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Affiliation(s)
- Sheng Zhang
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, 635 Barnhill Drive, Indianapolis, Indiana 46202, USA
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10
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Gómez CP, Tiemi Shio M, Duplay P, Olivier M, Descoteaux A. The protein tyrosine phosphatase SHP-1 regulates phagolysosome biogenesis. THE JOURNAL OF IMMUNOLOGY 2012; 189:2203-10. [PMID: 22826316 DOI: 10.4049/jimmunol.1103021] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The process of phagocytosis and phagosome maturation involves the recruitment of effector proteins that participate in phagosome formation and in the acidification and/or fusion with various endocytic vesicles. In the current study, we investigated the role of the Src homology region 2 domain-containing phosphatase 1 (SHP-1) in phagolysosome biogenesis. To this end, we used immortalized bone marrow macrophages derived from SHP-1-deficient motheaten mice and their wild-type littermates. We found that SHP-1 is recruited early and remains present on phagosomes for up to 4 h postphagocytosis. Using confocal immunofluorescence microscopy and Western blot analyses on purified phagosome extracts, we observed an impaired recruitment of lysosomal-associated membrane protein 1 in SHP-1-deficient macrophages. Moreover, Western blot analyses revealed that whereas the 51-kDa procathepsin D is recruited to phagosomes, it is not processed into the 46-kDa cathepsin D in the absence of SHP-1, suggesting a defect in acidification. Using the lysosomotropic agent LysoTracker as an indicator of phagosomal pH, we obtained evidence that in the absence of SHP-1, phagosome acidification was impaired. Taken together, these results are consistent with a role for SHP-1 in the regulation of signaling or membrane fusion events involved in phagolysosome biogenesis.
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Affiliation(s)
- Carolina P Gómez
- Institut National de la Recherche Scientifique-Institut Armand-Frappier, Laval, Quebec H7V 1B7, Canada
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11
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Hao Q, Samten B, Ji HL, Zhao ZJ, Tang H. Tyrosine phosphatase PTP-MEG2 negatively regulates vascular endothelial growth factor receptor signaling and function in endothelial cells. Am J Physiol Cell Physiol 2012; 303:C548-53. [PMID: 22763125 DOI: 10.1152/ajpcell.00415.2011] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Protein tyrosine phosphorylation is a fundamental mechanism for diverse physiological processes, which is regulated by protein tyrosine kinases and protein tyrosine phosphatases (PTPs). In this study, we searched for protein substrates of PTP-MEG2 (also called PTPN9), a nonreceptor PTP, and investigated its function in endothelial cells (ECs). By using a PTP-MEG2 substrate-trapping DA mutant, we found that a couple of tyrosine-phosphorylated proteins were associated with the DA mutant but not wild-type PTP-MEG2 and that the association was enhanced by vascular endothelial growth factor (VEGF) in ECs. We further found that VEGF receptor 2 (VEGFR2) was coimmunopricipitated with the DA mutant but not wild-type PTP-MEG2. The VEGF-induced phosphorylation of VEGFR2 on Tyr1175, a critical autophosphorylation site for VEGFR2 signaling, was inhibited 70% by overexpression of wild-type PTP-MEG2 but was enhanced (2.2-fold) by the DA mutant of PTP-MEG2. We also found that PTP-MEG2 DA mutant preferentially associated with Janus kinase 1 (JAK1) but not with other JAK kinases (Tyk2 and JAK2) present in ECs and regulated JAK1 tyrosine phosphorylation. Lastly, the VEGF-induced signal transduction and the production of interleukin (IL)-6 were significantly enhanced by PTP-MEG2 knockdown in ECs, whereas the VEGF-induced IL-6 production was inhibited 50% by PTP-MEG2 overexpression. Thus we have indentified VEGFR2 as a PTP-MEG2 substrate, and our findings indicate that PTP-MEG2 is a negative regulator of VEGFR2 signaling and function in ECs.
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Affiliation(s)
- Qin Hao
- Department of Biochemistry, University of Texas Health Science Center, Tyler, Texas 75708, USA
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12
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Ghosh R, Bankaitis VA. Phosphatidylinositol transfer proteins: negotiating the regulatory interface between lipid metabolism and lipid signaling in diverse cellular processes. Biofactors 2011; 37:290-308. [PMID: 21915936 DOI: 10.1002/biof.180] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Phosphoinositides represent only a small percentage of the total cellular lipid pool. Yet, these molecules play crucial roles in diverse intracellular processes such as signal transduction at membrane-cytosol interface, regulation of membrane trafficking, cytoskeleton organization, nuclear events, and the permeability and transport functions of the membrane. A central principle in such lipid-mediated signaling is the appropriate coordination of these events. Such an intricate coordination demands fine spatial and temporal control of lipid metabolism and organization, and consistent mechanisms for specifically coupling these parameters to dedicated physiological processes. In that regard, recent studies have identified Sec14-like phosphatidylcholine transfer protein (PITPs) as "coincidence detectors," which spatially and temporally link the diverse aspects of the cellular lipid metabolome with phosphoinositide signaling. The integral role of PITPs in eukaryotic signal transduction design is amply demonstrated by the mammalian diseases associated with the derangements in the function of these proteins, to stress response and developmental regulation in plants, to fungal dimorphism and pathogenicity, to membrane trafficking in yeast, and higher eukaryotes. This review updates the recent advances made in the understanding of how these proteins, specifically PITPs of the Sec14-protein superfamily, operate at the molecular level and further describes how this knowledge has advanced our perception on the diverse biological functions of PITPs.
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Affiliation(s)
- Ratna Ghosh
- Lineberger Comprehensive Cancer Center, Department of Cell and Developmental Biology, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC 27526-7090, USA.
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13
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Nile AH, Bankaitis VA, Grabon A. Mammalian diseases of phosphatidylinositol transfer proteins and their homologs. CLINICAL LIPIDOLOGY 2010; 5:867-897. [PMID: 21603057 PMCID: PMC3097519 DOI: 10.2217/clp.10.67] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Inositol and phosphoinositide signaling pathways represent major regulatory systems in eukaryotes. The physiological importance of these pathways is amply demonstrated by the variety of diseases that involve derangements in individual steps in inositide and phosphoinositide production and degradation. These diseases include numerous cancers, lipodystrophies and neurological syndromes. Phosphatidylinositol transfer proteins (PITPs) are emerging as fascinating regulators of phosphoinositide metabolism. Recent advances identify PITPs (and PITP-like proteins) to be coincidence detectors, which spatially and temporally coordinate the activities of diverse aspects of the cellular lipid metabolome with phosphoinositide signaling. These insights are providing new ideas regarding mechanisms of inherited mammalian diseases associated with derangements in the activities of PITPs and PITP-like proteins.
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Affiliation(s)
- Aaron H Nile
- Department of Cell & Developmental Biology, Lineberger Comprehensive Cancer Center School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-27090, USA
| | - Vytas A Bankaitis
- Department of Cell & Developmental Biology, Lineberger Comprehensive Cancer Center School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-27090, USA
| | - Aby Grabon
- Department of Cell & Developmental Biology, Lineberger Comprehensive Cancer Center School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-27090, USA
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14
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Katoh Y, Ritter B, Gaffry T, Blondeau F, Höning S, McPherson PS. The clavesin family, neuron-specific lipid- and clathrin-binding Sec14 proteins regulating lysosomal morphology. J Biol Chem 2009; 284:27646-54. [PMID: 19651769 PMCID: PMC2785693 DOI: 10.1074/jbc.m109.034884] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2009] [Revised: 07/20/2009] [Indexed: 11/06/2022] Open
Abstract
Clathrin-coated vesicles (CCVs) originating from the trans-Golgi network (TGN) provide a major transport pathway from the secretory system to endosomes/lysosomes. Herein we describe paralogous Sec14 domain-bearing proteins, clavesin 1/CRALBPL and clavesin 2, identified through a proteomic analysis of CCVs. Clavesins are enriched on CCVs and form a complex with clathrin heavy chain (CHC) and adaptor protein-1, major coat components of TGN-derived CCVs. The proteins co-localize with markers of endosomes and the TGN as well as with CHC and adaptor protein-1. A membrane mimic assay using the Sec14 domain of clavesin 1 reveals phosphatidylinositol 3,5-bisphosphate as a specific lipid partner. Phosphatidylinositol 3,5-bisphosphate is localized to late endosomes/lysosomes, and interestingly, isoform-specific knockdown of clavesins in neurons using lentiviral delivery of interfering RNA leads to enlargement of a lysosome-associated membrane protein 1-positive membrane compartment with no obvious influence on the CCV machinery at the TGN. Since clavesins are expressed exclusively in neurons, this new protein family appears to provide a unique neuron-specific regulation of late endosome/lysosome morphology.
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Affiliation(s)
- Yohei Katoh
- From the Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, Quebec H3A 2B4, Canada and
| | - Brigitte Ritter
- From the Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, Quebec H3A 2B4, Canada and
| | - Thomas Gaffry
- the Institute of Biochemistry I and Center for Molecular Medicine Cologne, University of Cologne, 50931 Cologne, Germany
| | - Francois Blondeau
- From the Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, Quebec H3A 2B4, Canada and
| | - Stefan Höning
- the Institute of Biochemistry I and Center for Molecular Medicine Cologne, University of Cologne, 50931 Cologne, Germany
| | - Peter S. McPherson
- From the Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, Quebec H3A 2B4, Canada and
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15
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Kwok V, Vachon E, Downey GP. Use of fluorescent probes to detect lipid signaling intermediates in macrophages. Methods Mol Biol 2009; 531:301-328. [PMID: 19347325 DOI: 10.1007/978-1-59745-396-7_19] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
To fulfill their function in host defense, professional phagocytes such as neutrophils and macrophages exhibit the ability to ingest (phagocytose), kill, and dispose of pathogenic microorganisms. Recent studies have provided strong evidence for the importance of membrane lipids such as polyphosphoinositides in these processes. In turn, reversible phosphorylation events, involving protein and lipid kinases and phosphatases, regulate signaling pathways involving metabolism of membrane lipids. Our ability to study lipid signaling events has been greatly facilitated by the development of fluorescent molecular imaging techniques. In particular, the expression of recombinant fusions of derivatives of the jellyfish-derived green fluorescent proteins (GFP) coupled to reporter molecules enables real-time monitoring of signaling events in live cells. Here, we discuss methods to monitor alterations in membrane polyphosphoinositides involved in signaling events regulating phagocytosis. To illustrate the use of this technology, we will focus on the role of protein tyrosine phosphatase MEG2 in phagocytosis and its modulation by phosphatidylinositol-3,4,5-triphosphate (PIP3). This approach enables investigators to ascertain the involvement of lipid intermediates in diverse signaling pathways.
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Affiliation(s)
- Vivian Kwok
- Department of Medicine, University of Toronto and Toronto General Hospital Research Institute of the University Health Network, Toronto, Ontario, Canada
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16
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Curwin AJ, McMaster CR. Structure and function of the enigmatic Sec14 domain-containing proteins and the etiology of human disease. ACTA ACUST UNITED AC 2008. [DOI: 10.2217/17460875.3.4.399] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
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17
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Saito K, Tautz L, Mustelin T. The lipid-binding SEC14 domain. Biochim Biophys Acta Mol Cell Biol Lipids 2007; 1771:719-26. [PMID: 17428729 DOI: 10.1016/j.bbalip.2007.02.010] [Citation(s) in RCA: 74] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2006] [Revised: 02/21/2007] [Accepted: 02/21/2007] [Indexed: 12/28/2022]
Abstract
Protein-lipid interactions are important for protein targeting, signal transduction, lipid transport, lipid biosynthesis, lipid metabolism, and the maintenance of cellular compartments and membranes. Specific lipid-binding protein domains, such as PH, FYVE, PX, PHD, C2 and SEC14 homology domains, mediate interactions between proteins and specific phospholipids. Here we review the published literature, plus some of our most recent unpublished findings, regarding the biology of the SEC14 domain, also known as CRAL_TRIO domain.
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Affiliation(s)
- Kan Saito
- The Burnham Institute for Medical Research, 10901 North Torrey Pines Road, La Jolla, CA 92037, USA
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18
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Saito K, Williams S, Bulankina A, Höning S, Mustelin T. Association of Protein-tyrosine Phosphatase MEG2 via Its Sec14p Homology Domain with Vesicle-trafficking Proteins. J Biol Chem 2007; 282:15170-8. [PMID: 17387180 DOI: 10.1074/jbc.m608682200] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
The protein-tyrosine phosphatase PTPMEG2 is located on the cytoplasmic face of the enclosing membrane of secretory vesicles, where it regulates vesicle size by promoting homotypic vesicle fusion by dephosphorylating N-ethylmaleimide-sensitive factor, a key regulator of vesicle fusion. Here we address the question of how PTPMEG2 is targeted to this subcellular location. Using a series of deletion mutants, we pinpointed the N-terminal Sec14p homology (SEC14) domain of PTPMEG2, residues 1-261, as the region containing the secretory vesicle targeting signal. This domain, alone or appended to a heterologous protein, was localized to intracellular vesicle membranes. Yeast two-hybrid screening identified a number of secretory vesicle proteins that interacted directly with the SEC14 domain of PTPMEG2, providing a mechanism for PTPMEG2 targeting to secretory vesicles. Two such proteins, mannose 6-phosphate receptor-interacting protein TIP47 and Arfaptin2, were found to alter PTPMEG2 localization when overexpressed, and elimination of TIP47 resulted in loss of PTPMEG2 function. We conclude that the N terminus of PTPMEG2 is necessary for the targeting of this phosphatase to the secretory vesicle compartment by association with other proteins involved in intracellular transport.
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Affiliation(s)
- Kan Saito
- Program on Inflammatory Disease Research, Infectious and Inflammatory Disease Center, and Program of Signal Transduction, Cancer Center, The Burnham Institute for Medical Research, La Jolla, California 92037, USA
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19
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Abstract
Tyrosyl phosphorylation plays a critical role in multiple signaling pathways regulating innate and acquired immunity. Although tyrosyl phosphorylation is a reversible process, we know much more about the functions of protein-tyrosine kinases (PTKs) than about protein-tyrosine phosphatases (PTPs). Genome sequencing efforts have revealed a large and diverse superfamily of PTPs, which can be subdivided into receptor-like (RPTPs) and nonreceptor (NRPTPs). The role of the RPTP CD45 in immune cell signaling is well known, but those of most other PTPs remain poorly understood. Here, we review the mechanism of action, regulation, and physiological functions of NRPTPs in immune cell signaling. Such an analysis indicates that PTPs are as important as PTKs in regulating the immune system.
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Affiliation(s)
- Lily I Pao
- Cancer Biology Program, Division of Hematology-Oncology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts 02215, USA.
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20
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Abstract
It is now well established that the members of the PTP (protein tyrosine phosphatase) superfamily play critical roles in fundamental biological processes. Although there has been much progress in defining the function of PTPs, the task of identifying substrates for these enzymes still presents a challenge. Many PTPs have yet to have their physiological substrates identified. The focus of this review will be on the current state of knowledge of PTP substrates and the approaches used to identify them. We propose experimental criteria that should be satisfied in order to rigorously assign PTP substrates as bona fide. Finally, the progress that has been made in defining the biological roles of PTPs through the identification of their substrates will be discussed.
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Affiliation(s)
- Tony Tiganis
- *Department of Biochemistry and Molecular Biology, Monash University, Victoria 3800, Australia
| | - Anton M. Bennett
- †Department of Pharmacology, Yale University School of Medicine, New Haven, CT 06520, U.S.A
- To whom correspondence should be addressed (email )
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21
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Fialkow L, Wang Y, Downey GP. Reactive oxygen and nitrogen species as signaling molecules regulating neutrophil function. Free Radic Biol Med 2007; 42:153-64. [PMID: 17189821 DOI: 10.1016/j.freeradbiomed.2006.09.030] [Citation(s) in RCA: 451] [Impact Index Per Article: 26.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/19/2006] [Revised: 09/27/2006] [Accepted: 09/28/2006] [Indexed: 02/06/2023]
Abstract
As a cornerstone of the innate immune response, neutrophils are the archetypical phagocytic cell; they actively seek out, ingest, and destroy pathogenic microorganisms. To achieve this essential role in host defense, neutrophils deploy a potent antimicrobial arsenal that includes oxidants, proteinases, and antimicrobial peptides. Importantly, oxidants produced by neutrophils, referred to in this article as reactive oxygen (ROS) and reactive nitrogen (RNS) species, have a dual function. On one hand they function as potent antimicrobial agents by virtue of their ability to kill microbial pathogens directly. On the other hand, they participate as signaling molecules that regulate diverse physiological signaling pathways in neutrophils. In the latter role, ROS and RNS serve as modulators of protein and lipid kinases and phosphatases, membrane receptors, ion channels, and transcription factors, including NF-kappaB. The latter regulates expression of key cytokines and chemokines that further modulate the inflammatory response. During the inflammatory response, ROS and RNS modulate phagocytosis, secretion, gene expression, and apoptosis. Under pathological circumstances such as acute lung injury and sepsis, excess production of ROS may influence vicinal cells such as endothelium or epithelium, contributing to inflammatory tissue injury. A better understanding of these pathways will help identify novel targets for amelioration of the untoward effects of inflammation.
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Affiliation(s)
- Lea Fialkow
- Faculty of Medicine, Universidade Federal do Rio Grande do Sul, Intensive Care Unit, Intensive Care Division, Hospital de Clínicas de Porto Alegre, Rio Grande do Sul, Brazil
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22
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McCulloch CA, Downey GP, El-Gabalawy H. Signalling platforms that modulate the inflammatory response: new targets for drug development. Nat Rev Drug Discov 2006; 5:864-76. [PMID: 17016427 DOI: 10.1038/nrd2109] [Citation(s) in RCA: 76] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Therapeutically controlling inflammation is essential for the clinical management of many high-prevalence human diseases. Drugs that block the pro-inflammatory cytokines tumour-necrosis factor-alpha and interleukin-1 (IL-1) can improve outcomes for rheumatoid arthritis and other inflammatory diseases but many patients remain refractory to treatment. Here we explore the need for developing new types of anti-inflammatory drugs and the emergence of novel drug targets based on the clustering of IL-1 receptors into multi-protein aggregates associated with cell adhesions. Interference with receptor aggregation into multi-protein complexes effectively abrogates IL-1 signalling. The exploration of the crucial molecules required for receptor clustering, and therefore signal transduction, offers new targets and scope for anti-inflammatory drug development.
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23
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Abstract
Neutrophils are critical inflammatory cells that cause tissue damage in a range of diseases and disorders. Being bone marrow-derived white blood cells, they migrate from the bloodstream to sites of tissue inflammation in response to chemotactic signals and induce inflammation by undergoing receptor-mediated respiratory burst and degranulation. Degranulation from neutrophils has been implicated as a major causative factor in pulmonary disorders, including severe asphyxic episodes of asthma. However, the mechanisms that control neutrophil degranulation are not well understood. Recent observations indicate that granule release from neutrophils depends on activation of intracellular signalling pathways, including β-arrestins, the Rho guanosine triphosphatase Rac2, soluble NSF attachment protein (SNAP) receptors, the src family of tyrosine kinases, and the tyrosine phosphatase MEG2. Some of these observations suggest that degranulation from neutrophils is selective and depends on nonredundant signalling pathways. This review focuses on new findings from the literature on the mechanisms that control the release of granule-derived mediators from neutrophils.
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Affiliation(s)
- Paige Lacy
- Pulmonary Research Group, Department of Medicine, University of Alberta, Edmonton, AB.
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24
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Cho CY, Koo SH, Wang Y, Callaway S, Hedrick S, Mak PA, Orth AP, Peters EC, Saez E, Montminy M, Schultz PG, Chanda SK. Identification of the tyrosine phosphatase PTP-MEG2 as an antagonist of hepatic insulin signaling. Cell Metab 2006; 3:367-78. [PMID: 16679294 DOI: 10.1016/j.cmet.2006.03.006] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/18/2005] [Revised: 12/01/2005] [Accepted: 03/09/2006] [Indexed: 10/24/2022]
Abstract
Insulin resistance is a primary defect in type 2 diabetes characterized by impaired peripheral glucose uptake and insufficient suppression of hepatic glucose output. Insulin signaling inhibits liver glucose production by inducing nuclear exclusion of the gluconeogenic transcription factor FOXO1 in an Akt-dependent manner. Through the concomitant application of genome-scale functional screening and quantitative image analysis, we have identified PTP-MEG2 as a modulator of insulin-dependent FOXO1 subcellular localization. Ectopic expression of PTP-MEG2 in cells inhibited insulin-induced phosphorylation of the insulin receptor, while RNAi-mediated reduction of PTP-MEG2 transcript levels enhanced insulin action. Additionally, adenoviral-mediated depletion of PTP-MEG2 in livers of diabetic (db/db) mice resulted in insulin sensitization and normalization of hyperglycemia. These data implicate PTP-MEG2 as a mediator of blood glucose homeostasis through antagonism of insulin signaling, and suggest that modulation of PTP-MEG2 activity may be an effective strategy in the treatment of type 2 diabetes.
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Affiliation(s)
- Charles Y Cho
- Genomics Institute of the Novartis Research Foundation, 10675 John Jay Hopkins Drive, San Diego, CA 92121, USA
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25
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Wang Y, Vachon E, Zhang J, Cherepanov V, Kruger J, Li J, Saito K, Shannon P, Bottini N, Huynh H, Ni H, Yang H, McKerlie C, Quaggin S, Zhao ZJ, Marsden PA, Mustelin T, Siminovitch KA, Downey GP. Tyrosine phosphatase MEG2 modulates murine development and platelet and lymphocyte activation through secretory vesicle function. ACTA ACUST UNITED AC 2006; 202:1587-97. [PMID: 16330817 PMCID: PMC2213338 DOI: 10.1084/jem.20051108] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
MEG2, a protein tyrosine phosphatase with a unique NH2-terminal lipid-binding domain, binds to and is modulated by the polyphosphoinositides PI(4,5)P2 and PI(3,4,5)P3. Recent data implicate MEG2 in vesicle fusion events in leukocytes. Through the genesis of Meg2-deficient mice, we demonstrate that Meg2−/−embryos manifest hemorrhages, neural tube defects including exencephaly and meningomyeloceles, cerebral infarctions, abnormal bone development, and >90% late embryonic lethality. T lymphocytes and platelets isolated from recombination activating gene 2−/− mice transplanted with Meg2−/− embryonic liver–derived hematopoietic progenitor cells showed profound defects in activation that, in T lymphocytes, was attributable to impaired interleukin 2 secretion. Ultrastructural analysis of these lymphocytes revealed near complete absence of mature secretory vesicles. Taken together, these observations suggest that MEG2-mediated modulation of secretory vesicle genesis and function plays an essential role in neural tube, vascular, and bone development as well as activation of mature platelets and lymphocytes.
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Affiliation(s)
- Yingchun Wang
- Division of Respirology, Department of Medicine, and the McLaughlin Center for Molecular Medicine, University of Toronto and Toronto General Hospital Research Institute of the University Health Network, Toronto, Ontario M5S 1A8, Canada
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26
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Zhao ZJ, Vainchenker W, Krantz SB, Casadevall N, Constantinescu SN. Role of Tyrosine Kinases and Phosphatases in Polycythemia Vera. Semin Hematol 2005; 42:221-9. [PMID: 16210035 DOI: 10.1053/j.seminhematol.2005.05.019] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Protein tyrosine kinases (PTKs) and phosphatases (PTPs) play a crucial role in normal cell development, and dysfunction of these enzymes has been implicated in human cancers. Polycythemia vera (PV) is a clonal hematologic disease characterized by hypersensitivity of hematopoietic progenitor cells to growth factors and cytokines. Recently, a unique and clonal mutation in the JAK homology 2 (JH2) domain of JAK2 that results in a valine to phenylalanine substitution at position 617 (V617F) was found in the majority of PV patients. This mutation leads to constitutive JAK2 activation and abnormal signaling and induces erythrocytosis in an animal model. The mutation is also found in a significant percentage of patients with idiopathic myelofibrosis (50%) and essential thrombocythemia (30%). Thus, it seems probable that this mutation associates with other molecular genetic events to cause different myeloproliferative disorders (MPDs). One of these secondary events is the transition to homozygosity of the mutated gene in 30% of the PV patients. Other events may include defects in PTPs, but these remain to be characterized. Recent studies represent a great step forward in the molecular pathogenesis in PV and the development of targeted new drugs to treat the disease.
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Affiliation(s)
- Zhizhuang Joe Zhao
- Hematology/Oncology Division, Department of Medicine, Vanderbilt-Ingram Cancer Center, Vanderbilt University School of Medicine, 2220 Pierce Avenue, Nashville, TN 37232, USA.
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27
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Huynh H, Bottini N, Williams S, Cherepanov V, Musumeci L, Saito K, Bruckner S, Vachon E, Wang X, Kruger J, Chow CW, Pellecchia M, Monosov E, Greer PA, Trimble W, Downey GP, Mustelin T. Control of vesicle fusion by a tyrosine phosphatase. Nat Cell Biol 2004; 6:831-9. [PMID: 15322554 DOI: 10.1038/ncb1164] [Citation(s) in RCA: 86] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2004] [Accepted: 07/29/2004] [Indexed: 12/12/2022]
Abstract
The tyrosine phosphatase PTP-MEG2 is targeted by its amino-terminal Sec14p homology domain to the membrane of secretory vesicles. There it regulates vesicle size by promoting homotypic vesicle fusion by a mechanism that requires its catalytic activity. Here, we identify N-ethylmaleimide-sensitive factor (NSF), a key regulator of vesicle fusion, as a substrate for PTP-MEG2. PTP-MEG2 reduced the phosphotyrosine content of NSF and co-localized with NSF and syntaxin 6 in intact cells. Furthermore, endogenous PTP-MEG2 co-immunoprecipitated with endogenous NSF. Phosphorylation of NSF at Tyr 83, as well as an acidic substitution at the same site, increased its ATPase activity and prevented alphaSNAP binding. Conversely, expression of a Y83F mutant of NSF caused spontaneous fusion events. Our results suggest that the molecular mechanism by which PTP-MEG2 promotes secretory vesicle fusion involves the local release of NSF from a tyrosine-phosphorylated, inactive state. This represents a novel mechanism for localized regulation of NSF and the first demonstrated role for a protein tyrosine phosphatase in the regulated secretory pathway.
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Affiliation(s)
- Huong Huynh
- Program of Inflammation, Infectious and Inflammatory Disease Center, and Program of Signal Transduction, Cancer Center, The Burnham Institute, 10901 North Torrey Pines Road, La Jolla, CA 92037, USA
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28
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Huynh H, Wang X, Li W, Bottini N, Williams S, Nika K, Ishihara H, Godzik A, Mustelin T. Homotypic secretory vesicle fusion induced by the protein tyrosine phosphatase MEG2 depends on polyphosphoinositides in T cells. THE JOURNAL OF IMMUNOLOGY 2004; 171:6661-71. [PMID: 14662869 DOI: 10.4049/jimmunol.171.12.6661] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Sec14p homology domains are found in a large number of proteins from plants, yeast, invertebrates, and higher eukaryotes. We report that the N-terminal Sec14p homology domain of the human protein tyrosine phosphatase PTP-MEG2 binds phosphatidylinositol-3,4,5-trisphosphate (PtdIns(3,4,5)P(3)) in vitro and colocalizes with this lipid on secretory vesicle membranes in intact cells. Point mutations that prevented PtdIns(3,4,5)P(3) binding abrogated the capacity of PTP-MEG2 to induce homotypic secretory vesicle fusion in cells. Inhibition of cellular PtdIns(3,4,5)P(3) synthesis also rapidly reversed the effect of PTP-MEG2 on secretory vesicles. Finally, we show that several different phosphoinositide kinases colocalize with PTP-MEG2, thus allowing for local synthesis of PtdIns(3,4,5)P(3) in secretory vesicle membranes. We suggest that PTP-MEG2 through its Sec14p homology domain couples inositide phosphorylation to tyrosine dephosphorylation and the regulation of intracellular traffic of the secretory pathway in T cells.
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Affiliation(s)
- Huong Huynh
- Program of Signal Transduction, Cancer Research Center, The Burnham Institute, La Jolla, CA 92037, USA
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29
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Xu MJ, Sui X, Zhao R, Dai C, Krantz SB, Zhao ZJ. PTP-MEG2 is activated in polycythemia vera erythroid progenitor cells and is required for growth and expansion of erythroid cells. Blood 2003; 102:4354-60. [PMID: 12920026 DOI: 10.1182/blood-2003-04-1308] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Polycythemia vera (PV) is a human clonal hematologic disorder. Previously we demonstrated that erythroid colony-forming cells (ECFCs) from PV patients contained a hyperactive membrane-associated tyrosine phosphatase. We now show that this phosphatase corresponded to protein tyrosine phosphatase (PTP)-MEG2, an intracellular enzyme with a putative lipid-binding domain. The increased activity of PTP-MEG2 in PV cells is due to its elevated distribution in the membrane fraction. With the development of ECFCs to mature red cells, the protein level of PTP-MEG2 decreased gradually, but membrane-associated PTP-MEG2 was sustained for a longer period of time in PV cells, which correlated with an enhanced colony-forming capability of the cells. Importantly, expression of dominant-negative mutant forms of PTP-MEG2 suppressed in vitro growth and expansion of both normal and PV ECFCs. The data indicate that PTP-MEG2 has an important role in the development of erythroid cells.
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Affiliation(s)
- Ming-Jiang Xu
- Hematology/Oncology Division, Department of Medicine, Department of Veterans Affairs Medical Center, Nashville, TN, USA
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30
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Gilljam M, Moltyaner Y, Downey GP, Devlin R, Durie P, Cantin AM, Zielenski J, Tullis DE. Airway inflammation and infection in congenital bilateral absence of the vas deferens. Am J Respir Crit Care Med 2003; 169:174-9. [PMID: 14551163 DOI: 10.1164/rccm.200304-558oc] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
In cystic fibrosis (CF), airway disease begins early in life. Bacteria and elevated levels of neutrophils and inflammatory mediators have been detected in bronchoalveolar lavage (BAL) fluid from infants with CF. Mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) are common in men with congenital bilateral absence of the vas deferens (CBAVD) and it has been suggested that this syndrome represents a mild form of CF. We hypothesized that men with CBAVD also have subclinical pulmonary disease. Bronchoscopy with BAL, viral and quantitative bacterial cultures, and analyses of total and differential cell count, cytokines, and free neutrophil elastase was performed in eight men with CBAVD, who had mutations in the CFTR and intermediate or elevated sweat chloride levels, and in four healthy control subjects. There was light growth of Staphylococcus aureus in one of eight men with CBAVD, and small numbers of opportunistic gram-negative bacteria in six of eight men with CBAVD and in one control subject. BAL cell counts and neutrophil elastase were within the normal range. Interleukin-8 and tumor necrosis factor-alpha levels were higher for men with CBAVD than for control subjects. These data suggest that mutations in the CFTR in men with CBAVD, in addition to causing infertility, lead to subclinical bacterial pulmonary infection and inflammation consistent with mild CF.
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Affiliation(s)
- Marita Gilljam
- Department of Respiratory Medicine and Allergology, Sahlgrenska University Hospital, Göteborg University, Sweden
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31
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Zhao R, Fu X, Li Q, Krantz SB, Zhao ZJ. Specific interaction of protein tyrosine phosphatase-MEG2 with phosphatidylserine. J Biol Chem 2003; 278:22609-14. [PMID: 12702726 DOI: 10.1074/jbc.m301560200] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Protein tyrosine phosphatase (PTP)-MEG2 is an intracellular tyrosine phosphatase that contains a Sec14 homology domain. We have purified the full-length and truncated forms of the enzyme from recombinant adenovirus-infected human 293 cells. By using lipid-membrane overlay and liposome binding assays, we demonstrated that PTP-MEG2 specifically binds phosphatidylserine among over 20 lipid compounds tested. The binding is mediated by its N-terminal Sec14 domain. In intact cells, the Sec14 domain is responsible for localization of PTP-MEG2 to the perinuclear region, and uploading of PS into the cell membrane causes translocation of PTP-MEG2 to the plasma membrane. Phosphatidylserine is a relatively abundant cell membrane phospholipid non-symmetrically distributed in the outer layer and inner layer of cell membranes. It has recently been defined as an important ligand for clearance of apoptotic cells. By specifically binding phosphatidylserine, PTP-MEG2 may play an important role in regulating signaling processes associated with phagocytosis of apoptotic cells.
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Affiliation(s)
- Runxiang Zhao
- Hematology/Oncology Division, Department of Medicine, Vanderbilt University, Nashville, Tennessee 37232, USA
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Kempná P, Zingg JM, Ricciarelli R, Hierl M, Saxena S, Azzi A. Cloning of novel human SEC14p-like proteins: ligand binding and functional properties. Free Radic Biol Med 2003; 34:1458-72. [PMID: 12757856 DOI: 10.1016/s0891-5849(03)00173-4] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
We describe the cloning and expression of two novel genes highly similar to the tocopherol-associated protein (hTAP/SEC14L2/SPF). Immunoprecipitation of the three recombinant hTAPs and extraction of their associated lipid-soluble molecules indicates that they bind not just tocopherols, but also phosphatidylinositol, phosphatidylcholine, and phosphatidylglycerol. Ligand competition analysis by isoelectric point mobility shift assay indicates that phosphatidylcholine, tocopherols, and tocopheryl-succinate compete with phosphatidylinositol binding to hTAPs. To investigate a possible function of hTAPs on enzymes involved in phospholipids metabolism, the activity of recombinant phosphatidylinositol 3-kinase (PI3Kgamma/p110gamma) was tested. Recombinant hTAPs reduce in vitro the activity of the recombinant catalytic subunit of PI3Kgamma and stimulate it in the presence of alpha-tocopherol up to 5-fold. Immunoprecipitation of hTAP1 from cells results in co-precipitation of PI3-kinase activity, indicating a physical contact between the two proteins at a cellular level. In summary, hTAPs may modulate, in a tocopherol-sensitive manner, phosphatidylinositol-3-kinase, a central enzyme in signal transduction, cell proliferation, and apoptosis. It is possible that other phosphatidylinositol- and phosphatidylcholine-dependent signaling pathways are modulated by hTAPs and tocopherols, possibly by transporting and presenting these ligands to the corresponding enzymes.
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Affiliation(s)
- Petra Kempná
- Institute of Biochemistry and Molecular Biology, University of Bern, Bühlstrasse 28, CH-3012 Bern, Switzerland
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Qi Y, Zhao R, Cao H, Sui X, Krantz SB, Zhao ZJ. Purification and characterization of protein tyrosine phosphatase PTP-MEG2. J Cell Biochem 2002; 86:79-89. [PMID: 12112018 DOI: 10.1002/jcb.10195] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
PTP-MEG2 is an intracellular protein tyrosine phosphatase with a putative lipid-binding domain at the N-terminus. The present study reports expression, purification, and characterization of the full-length form of the enzyme plus a truncated form containing the catalytic domain alone. Full-length PTP-MEG2 was expressed with an adenovirus system and purified from cytosolic extracts of human 293 cells infected with the recombinant adenovirus. The purification scheme included chromatographic separation of cytosolic extracts on fast flow Q-Sepharose, heparin-agarose, l-histidyldiazobenzylphosphonic acid agarose, and hydroxylapatite. The enrichment of PTP-MEG2 from the cytosol was about 120-fold. The truncated form of PTP-MEG2 was expressed in E. coli cells as a non-fusion protein and purified by using a chromatographic procedure similar to that used for the full-length enzyme. The purified full-length and truncated enzymes showed single polypeptide bands on SDS-polyacrylamide gel electrophoresis under reducing conditions and behaved as monomers on gel exclusion chromatography. With para-nitrophenylphosphate and phosphotyrosine as substrates, both forms of the enzyme exhibited classical Michaelis-Menten kinetics. Their responses to pH, ionic strength, metal ions, and protein phosphatase inhibitors are similar to those observed with other characterized tyrosine phosphatases. Compared with full-length PTP-MEG2, the truncated DeltaPTP-MEG2 displayed significantly higher V(max) and lower K(m) values, suggesting that the N-terminal putative lipid-binding domain may have an inhibitory role. The full-length and truncated forms of PTP-MEG2 were also expressed as GST fusion proteins in E. coli cells and purified to near homogeneity through affinity columns. However, the specific phosphatase activities of the GST fusion proteins were 10-25-fold below those obtained with the correspondent non-fusion proteins.
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Affiliation(s)
- Ying Qi
- Division of Hematology/Oncology, Department of Medicine, Department of Veterans Affairs Medical Center, Vanderbilt-Ingram Cancer Center, Vanderbilt University, Nashville, Tennessee 37232, USA
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García‐García E, Rosales C. Signal transduction during Fc receptor‐mediated phagocytosis. J Leukoc Biol 2002. [DOI: 10.1189/jlb.72.6.1092] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Affiliation(s)
- Erick García‐García
- Immunology Department, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Mexico City
| | - Carlos Rosales
- Immunology Department, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Mexico City
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