1
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Chmielewska JJ, Burkardt D, Granadillo JL, Slaugh R, Morgan S, Rotenberg J, Keren B, Mignot C, Escobar L, Turnpenny P, Zuteck M, Seaver LH, Ploski R, Dziembowska M, Wynshaw-Boris A, Adegbola A. PTPN4 germline variants result in aberrant neurodevelopment and growth. HGG ADVANCES 2021; 2:100033. [PMID: 34527963 PMCID: PMC8439436 DOI: 10.1016/j.xhgg.2021.100033] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2020] [Accepted: 03/31/2021] [Indexed: 11/29/2022] Open
Abstract
Protein-tyrosine phosphatases (PTPs) are pleomorphic regulators of eukaryotic cellular responses to extracellular signals that function by modulating the phosphotyrosine of specific proteins. A handful of PTPs have been implicated in germline and somatic human disease. Using exome sequencing, we identified missense and truncating variants in PTPN4 in six unrelated individuals with varying degrees of intellectual disability or developmental delay. The variants occurred de novo in all five subjects in whom segregation analysis was possible. Recurring features include postnatal growth deficiency or excess, seizures, and, less commonly, structural CNS, heart, or skeletal anomalies. PTPN4 is a widely expressed protein tyrosine phosphatase that regulates neuronal cell homeostasis by protecting neurons against apoptosis. We suggest that pathogenic variants in PTPN4 confer risk for growth and cognitive abnormalities in humans.
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Affiliation(s)
- Joanna J. Chmielewska
- Postgraduate School of Molecular Medicine, Medical University of Warsaw, Warsaw, Poland
- Laboratory of Molecular Basis of Synaptic Plasticity, Centre of New Technologies, University of Warsaw, Warsaw, Poland
| | - Deepika Burkardt
- Center for Human Genetics and Department of Genetics and Genome Sciences, University Hospitals Cleveland Medical Center and Case Western Reserve University, Cleveland, OH, USA
| | - Jorge Luis Granadillo
- Division of Genetics and Genomic Medicine, Department of Pediatrics, Washington University School of Medicine, St. Louis, MO, USA
| | - Rachel Slaugh
- Division of Genetics and Genomic Medicine, Department of Pediatrics, Washington University School of Medicine, St. Louis, MO, USA
| | | | | | - Boris Keren
- Département de Génétique, APHP, Sorbonne Université, Groupe Hospitalier Pitié-Salpêtrière, Paris, France
| | - Cyril Mignot
- Département de Génétique, APHP, Sorbonne Université, Groupe Hospitalier Pitié-Salpêtrière, Paris, France
- Centre de Référence Déficiences Intellectuelles de Causes Rares, Paris, France
| | - Luis Escobar
- Medical Genetics and Neurodevelopmental Center, Peyton Manning Children’s Hospital, Indianapolis, IN, USA
| | - Peter Turnpenny
- University of Exeter Medical School and Royal Devon and Exeter NHS Foundation Trust, Exeter, UK
| | - Melissa Zuteck
- Medical Genetics and Genomics, Spectrum Health/Helen Devos Children’s Hospital, Grand Rapids, MI, USA
| | - Laurie H. Seaver
- Medical Genetics and Genomics, Spectrum Health/Helen Devos Children’s Hospital, Grand Rapids, MI, USA
- Department of Pediatrics and Human Development, Michigan State College of Human Medicine, Grand Rapids, MI, USA
| | - Rafal Ploski
- Department of Medical Genetics, Warsaw Medical University, Warsaw, Poland
| | - Magdalena Dziembowska
- Laboratory of Molecular Basis of Synaptic Plasticity, Centre of New Technologies, University of Warsaw, Warsaw, Poland
| | - Anthony Wynshaw-Boris
- Center for Human Genetics and Department of Genetics and Genome Sciences, University Hospitals Cleveland Medical Center and Case Western Reserve University, Cleveland, OH, USA
| | - Abidemi Adegbola
- Center for Human Genetics and Department of Genetics and Genome Sciences, University Hospitals Cleveland Medical Center and Case Western Reserve University, Cleveland, OH, USA
- Department of Psychiatry, University Hospitals Cleveland Medical Center and Case Western Reserve University, Cleveland, OH, USA
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2
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Shen N, Wang P, Li Y, Zhu Y, Gong Y, Zhong R, Lu Y, Cheng L. Nonreceptor protein tyrosine phosphatases (NRPTPs) gene family associates with the risk of hepatocellular carcinoma in a Chinese hepatitis B virus-related subjects. Mol Carcinog 2020; 59:980-988. [PMID: 32484301 DOI: 10.1002/mc.23228] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2020] [Revised: 05/09/2020] [Accepted: 05/18/2020] [Indexed: 11/07/2022]
Abstract
Nonreceptor protein tyrosine phosphatases (NRPTPs) are reported to be associated with several human cancers, but their roles in hepatitis B virus (HBV)-related hepatocellular carcinoma (HCC) remain unclear. Here, we integrated bioinformatics tools, population association analyses, and biological assays to systematically screen for potentially functional single nucleotide polymorphisms (SNPs) within the 17 NRPTPs genes and evaluate the effects of candidate SNPs on the risk of HCC or persistent HBV infection. A total of 790 HBV-related HCC cases and 1454 cancer-free controls were enrolled. Controls included 711 HBV persistent carriers and 743 spontaneously recovered subjects. Results demonstrated that PTPN4 rs9308777 (odds ratio [OR] = 1.25, 95% confidence interval [CI] = 1.06-1.49, P = .009) and PTPN12 rs350050 (OR = 1.26, 95% CI = 1.10-1.45, P = .001), were significantly associated with HCC risk, but not with persistent HBV infection risk. The cumulative risk effect of these two SNPs was more significantly increased the susceptibility to HCC (OR = 1.27, 95% CI = 1.14-1.41, P = 2.40 × 10-5 ). Subsequent biological assays further revealed the potential pathogenesis that PTPN4 rs9308777 might decrease the gene expression, and PTPN12 rs3750050 might promote cell proliferation by attenuating PTPN12's inhibitory activity on EGFR/ERK pathway. In summary, our integrative study highlights that PTPN4 and PTPN12 are significantly associated with HBV-related HCC risk, but do not influence persistent HBV infection. These findings shed light on the importance of the synergistic effects of regulatory and missense variants on the risk for HCC, and provide data to support personalized cancer medicine in the future.
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Affiliation(s)
- Na Shen
- Department of Laboratory Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Peng Wang
- Institute and Department of Infectious Disease, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Ying Li
- Department of Laboratory Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Yaowu Zhu
- Department of Laboratory Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Yajie Gong
- Department of Epidemiology and Biostatistics, MOE Key Laboratory of Environment and Health, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Rong Zhong
- Department of Epidemiology and Biostatistics, MOE Key Laboratory of Environment and Health, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Yanjun Lu
- Department of Laboratory Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Liming Cheng
- Department of Laboratory Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
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3
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Zhang BD, Li YR, Ding LD, Wang YY, Liu HY, Jia BQ. Loss of PTPN4 activates STAT3 to promote the tumor growth in rectal cancer. Cancer Sci 2019; 110:2258-2272. [PMID: 31025789 PMCID: PMC6609803 DOI: 10.1111/cas.14031] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2018] [Revised: 04/22/2019] [Accepted: 04/24/2019] [Indexed: 01/16/2023] Open
Abstract
Colorectal cancer (CRC) is one of the most common types of malignant tumor. Many genetic factors have been proved to show high association with the occurrence and development of CRC and many mutations are detected in CRC. PTPN4/PTP‐MEG1 is a widely expressed non–receptor protein tyrosine phosphatase. Over the past three decades, PTPN4 has been demonstrated in the literature to participate in many biological processes. In this study, we identified a nonsense mutation of PTPN4 with a mutation ratio of 90.90% from 1 case of rectal cancer, leading to loss of function in PTPN4 gene. Several somatic mutations occurred in 5/137 rectal cancer samples from The Cancer Genome Atlas Rectum Adenocarcinoma (TCGA READ) database. Interestingly, we found that PTPN4 negative cytoplasm staining was more prone to lymphatic metastasis (N = 50, P = 0.0153) and low expression of PTPN4 in rectal cancer was highly associated with poor prognosis. Overexpression of PTPN4 suppressed the cell growth, and moreover, the loss of PTPN4 accelerated cell growth and boosted clonogenicity of CRC cells. Furthermore, we revealed that the deletion of PTPN4 promoted the tumor formation of NCM460 cells in vivo. In terms of the molecular mechanism, we demonstrated that PTPN4 dephosphorylates pSTAT3 at the Tyr705 residue with a direct interaction and suppresses the transcriptional activity of STAT3. In summary, our study revealed a novel mechanism that the tumorigenesis of colorectal cancer might be caused by the loss of PTPN4 through activating STAT3, which will broaden the therapy strategy for anti–rectal cancer in the future.
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Affiliation(s)
| | - Yue-Rui Li
- Chinese PLA General Hospital, Beijing, China
| | - Li-Dan Ding
- State Key Laboratory of Membrane Biology, Department of Basic Medical Sciences, School of Medicine, Tsinghua University, Beijing, China
| | - Yin-Yin Wang
- State Key Laboratory of Membrane Biology, Department of Basic Medical Sciences, School of Medicine, Tsinghua University, Beijing, China
| | - Hong-Yi Liu
- Chinese PLA General Hospital, Beijing, China
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4
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Stebbing J, Lit LC, Zhang H, Darrington RS, Melaiu O, Rudraraju B, Giamas G. The regulatory roles of phosphatases in cancer. Oncogene 2014; 33:939-53. [PMID: 23503460 DOI: 10.1038/onc.2013.80] [Citation(s) in RCA: 77] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2013] [Accepted: 02/01/2013] [Indexed: 02/06/2023]
Abstract
The relevance of potentially reversible post-translational modifications required for controlling cellular processes in cancer is one of the most thriving arenas of cellular and molecular biology. Any alteration in the balanced equilibrium between kinases and phosphatases may result in development and progression of various diseases, including different types of cancer, though phosphatases are relatively under-studied. Loss of phosphatases such as PTEN (phosphatase and tensin homologue deleted on chromosome 10), a known tumour suppressor, across tumour types lends credence to the development of phosphatidylinositol 3-kinase inhibitors alongside the use of phosphatase expression as a biomarker, though phase 3 trial data are lacking. In this review, we give an updated report on phosphatase dysregulation linked to organ-specific malignancies.
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Affiliation(s)
- J Stebbing
- Division of Cancer, Department of Surgery and Cancer, Imperial College London, London, UK
| | - L C Lit
- Division of Cancer, Department of Surgery and Cancer, Imperial College London, London, UK
| | - H Zhang
- Division of Cancer, Department of Surgery and Cancer, Imperial College London, London, UK
| | - R S Darrington
- Division of Cancer, Department of Surgery and Cancer, Imperial College London, London, UK
| | - O Melaiu
- Division of Cancer, Department of Surgery and Cancer, Imperial College London, London, UK
| | - B Rudraraju
- Division of Cancer, Department of Surgery and Cancer, Imperial College London, London, UK
| | - G Giamas
- Division of Cancer, Department of Surgery and Cancer, Imperial College London, London, UK
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5
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PTPN4 negatively regulates CrkI in human cell lines. Cell Mol Biol Lett 2013; 18:297-314. [PMID: 23666597 PMCID: PMC6275623 DOI: 10.2478/s11658-013-0090-3] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2013] [Accepted: 04/23/2013] [Indexed: 11/20/2022] Open
Abstract
PTPN4 is a widely expressed non-receptor protein tyrosine phosphatase. Although its overexpression inhibits cell growth, the proteins with which it interacts to regulate cell growth are unknown. In this study, we identified CrkI as a PTPN4-interacting protein using a yeast two-hybrid, and confirmed this interaction using in vitro GST pull-down and co-immunoprecipitation and co-localization assays. We further determined the interactional regions as the SH3 domain of CrkI and the proline-rich region between amino acids 462 and 468 of PTPN4. Notably, overexpression of PTPN4 inhibits CrkI-mediated proliferation and wound healing of HEK293T cells, while knockdown of PTPN4 by siRNA in Hep3B cells enhances CrkI-mediated cell growth and motility. Moreover, our data show that ectopic expression of PTPN4 reduces the phosphorylation level of CrkI in HEK293T cells. These findings suggest that PTPN4 negatively regulates cell proliferation and motility through dephosphorylation of CrkI.
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6
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Matsumoto C, Ito M, Yamada H, Yamakawa N, Yoshida H, Date A, Watanabe M, Hidaka Y, Iwatani Y, Miyauchi A, Takano T. Genes that characterize T3-predominant Graves' thyroid tissues. Eur J Endocrinol 2013; 168:137-44. [PMID: 23109646 DOI: 10.1530/eje-12-0507] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
OBJECTIVE 3,5,3'-Triiodothyronine (T(3))-predominant Graves' disease is characterized by the increasing volume of thyroid goiter resulting in poor prognosis. Although type 1 and type 2 iodothyronine deiodinases (DIO1 and DIO2 respectively) are known to be overexpressed in the thyroid tissues of T(3)-predominant Graves' disease, the pathogenesis of this disease is still unclear. The aim of our study is to identify genes that characterize T(3)-predominant Graves' disease tissue in order to clarify the molecular mechanism of this disease. DESIGN AND METHODS mRNAs from two thyroid tissues of both typical T(3)-predominant and common-type Graves' disease were analyzed with DNA microarrays with probes for 28 869 genes. Genes identified to be differentially expressed between the two groups were further analyzed in the second and third screenings using 70 Graves' thyroid tissues by real-time quantitative RT-PCR. RESULTS Twenty-three candidate genes were selected as being differentially expressed in the first screening with microarrays. Among these, seven genes, leucine-rich repeat neuronal 1 (LRRN1), bone morphogenetic protein 8a (BMP8A), N-cadherin (CDH2), phosphodiesterase 1A (PDE1A), creatine kinase mitochondrial 2 (CKMT2), integrin beta-3 (ITGB3), and protein tyrosine phosphatase non-receptor type 4 (PTPN4), were confirmed to be differentially expressed in DIO1 or DIO2 over- and underexpressing Graves' tissues. CONCLUSIONS These genes are related to the characteristics of T(3)-predominant Graves' disease, such as high titer level of serum anti-TSH receptor antibody, high free T(3) to free thyroxine ratio, and a large goiter size. They might play a role in the pathogenesis of T(3)-predominant Graves' disease.
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Affiliation(s)
- Chisa Matsumoto
- Department of Laboratory Medicine, Osaka University Graduate School of Medicine, D2, 2-2 Yamadaoka, Suita, Osaka 565-0871, Japan
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7
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Stanford SM, Rapini N, Bottini N. Regulation of TCR signalling by tyrosine phosphatases: from immune homeostasis to autoimmunity. Immunology 2012; 137:1-19. [PMID: 22862552 DOI: 10.1111/j.1365-2567.2012.03591.x] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
More than half of the known protein tyrosine phosphatases (PTPs) in the human genome are expressed in T cells, and significant progress has been made in elucidating the biology of these enzymes in T-cell development and function. Here we provide a systematic review of the current understanding of the roles of PTPs in T-cell activation, providing insight into their mechanisms of action and regulation in T-cell receptor signalling, the phenotypes of their genetically modified mice, and their possible involvement in T-cell-mediated autoimmune disease. Our projection is that the interest in PTPs as mediators of T-cell homeostasis will continue to rise with further functional analysis of these proteins, and PTPs will be increasingly considered as targets of immunomodulatory therapies.
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Affiliation(s)
- Stephanie M Stanford
- Division of Cellular Biology, La Jolla Institute for Allergy and Immunology, La Jolla, CA 92037, USA
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8
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Pan CQ, Low BC. Functional plasticity of the BNIP-2 and Cdc42GAP Homology (BCH) domain in cell signaling and cell dynamics. FEBS Lett 2012; 586:2674-91. [DOI: 10.1016/j.febslet.2012.04.023] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2012] [Revised: 04/16/2012] [Accepted: 04/16/2012] [Indexed: 10/28/2022]
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9
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Gupta AB, Wee LE, Zhou YT, Hortsch M, Low BC. Cross-species analyses identify the BNIP-2 and Cdc42GAP homology (BCH) domain as a distinct functional subclass of the CRAL_TRIO/Sec14 superfamily. PLoS One 2012; 7:e33863. [PMID: 22479462 PMCID: PMC3313917 DOI: 10.1371/journal.pone.0033863] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2011] [Accepted: 02/18/2012] [Indexed: 11/19/2022] Open
Abstract
The CRAL_TRIO protein domain, which is unique to the Sec14 protein superfamily, binds to a diverse set of small lipophilic ligands. Similar domains are found in a range of different proteins including neurofibromatosis type-1, a Ras GTPase-activating Protein (RasGAP) and Rho guanine nucleotide exchange factors (RhoGEFs). Proteins containing this structural protein domain exhibit a low sequence similarity and ligand specificity while maintaining an overall characteristic three-dimensional structure. We have previously demonstrated that the BNIP-2 and Cdc42GAP Homology (BCH) protein domain, which shares a low sequence homology with the CRAL_TRIO domain, can serve as a regulatory scaffold that binds to Rho, RhoGEFs and RhoGAPs to control various cell signalling processes. In this work, we investigate 175 BCH domain-containing proteins from a wide range of different organisms. A phylogenetic analysis with ∼100 CRAL_TRIO and similar domains from eight representative species indicates a clear distinction of BCH-containing proteins as a novel subclass within the CRAL_TRIO/Sec14 superfamily. BCH-containing proteins contain a hallmark sequence motif R(R/K)h(R/K)(R/K)NL(R/K)xhhhhHPs (‘h’ is large and hydrophobic residue and ‘s’ is small and weekly polar residue) and can be further subdivided into three unique subtypes associated with BNIP-2-N, macro- and RhoGAP-type protein domains. A previously unknown group of genes encoding ‘BCH-only’ domains is also identified in plants and arthropod species. Based on an analysis of their gene-structure and their protein domain context we hypothesize that BCH domain-containing genes evolved through gene duplication, intron insertions and domain swapping events. Furthermore, we explore the point of divergence between BCH and CRAL-TRIO proteins in relation to their ability to bind small GTPases, GAPs and GEFs and lipid ligands. Our study suggests a need for a more extensive analysis of previously uncharacterized BCH, ‘BCH-like’ and CRAL_TRIO-containing proteins and their significance in regulating signaling events involving small GTPases.
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Affiliation(s)
- Anjali Bansal Gupta
- Department of Biological Sciences, National University of Singapore, Singapore, Singapore
- Mechanobiology Institute, National University of Singapore, Singapore, Singapore
| | - Liang En Wee
- Department of Biological Sciences, National University of Singapore, Singapore, Singapore
| | - Yi Ting Zhou
- Department of Biological Sciences, National University of Singapore, Singapore, Singapore
| | - Michael Hortsch
- Department of Cell and Developmental Biology, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Boon Chuan Low
- Department of Biological Sciences, National University of Singapore, Singapore, Singapore
- Mechanobiology Institute, National University of Singapore, Singapore, Singapore
- * E-mail:
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10
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Seo HY, Lee IS, Cho SE. Protein Tyrosine Phosphatase H1 (PTPH1) Inhibits LPS-induced TNF-α Production. B KOREAN CHEM SOC 2010. [DOI: 10.5012/bkcs.2010.31.12.3812] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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11
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Abstract
Tyrosine phosphorylation and dephosphorylation of proteins play a critical role for many T-cell functions. The opposing actions of protein tyrosine kinases (PTKs) and protein tyrosine phosphatases (PTPs) determine the level of tyrosine phosphorylation at any time. It is well accepted that PTKs are essential during T-cell signaling; however, the role and importance of PTPs are much less known and appreciated. Both transmembrane and cytoplasmic tyrosine phosphatases have been identified in T cells and shown to regulate T-cell responses. This review focuses on the roles of the two cytoplasmic PTPs, the Src-homology 2 domain (SH2)-containing SHP-1 and SHP-2, in T-cell signaling, development, differentiation, and function.
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Affiliation(s)
- Ulrike Lorenz
- Department of Microbiology and The Beirne Carter Center for Immunology Research, University of Virginia, Charlottesville, VA 22908-0734, USA.
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12
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Bauler TJ, Hendriks WJAJ, King PD. The FERM and PDZ domain-containing protein tyrosine phosphatases, PTPN4 and PTPN3, are both dispensable for T cell receptor signal transduction. PLoS One 2008; 3:e4014. [PMID: 19107198 PMCID: PMC2602985 DOI: 10.1371/journal.pone.0004014] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2008] [Accepted: 11/24/2008] [Indexed: 11/18/2022] Open
Abstract
PTPN3 and PTPN4 are two closely-related non-receptor protein tyrosine phosphatases (PTP) that, in addition to a PTP domain, contain FERM (Band 4.1, Ezrin, Radixin, and Moesin) and PDZ (PSD-95, Dlg, ZO-1) domains. Both PTP have been implicated as negative-regulators of early signal transduction through the T cell antigen receptor (TCR), acting to dephosphorylate the TCRzeta chain, a component of the TCR complex. Previously, we reported upon the production and characterization of PTPN3-deficient mice which show normal TCR signal transduction and T cell function. To address if the lack of a T cell phenotype in PTPN3-deficient mice can be explained by functional redundancy of PTPN3 with PTPN4, we generated PTPN4-deficient and PTPN4/PTPN3 double-deficient mice. As in PTPN3 mutants, T cell development and homeostasis and TCR-induced cytokine synthesis and proliferation were found to be normal in PTPN4-deficient and PTPN4/PTPN3 double-deficient mice. PTPN13 is another FERM and PDZ domain-containing non-receptor PTP that is distantly-related to PTPN3 and PTPN4 and which has been shown to function as a negative-regulator of T helper-1 (Th1) and Th2 differentiation. Therefore, to determine if PTPN13 might compensate for the loss of PTPN3 and PTPN4 in T cells, we generated mice that lack functional forms of all three PTP. T cells from triple-mutant mice developed normally and showed normal cytokine secretion and proliferative responses to TCR stimulation. Furthermore, T cell differentiation along the Th1, Th2 and Th17 lineages was largely unaffected in triple-mutants. We conclude that PTPN3 and PTPN4 are dispensable for TCR signal transduction.
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MESH Headings
- Animals
- Cell Differentiation/genetics
- Cell Differentiation/immunology
- Cells, Cultured
- Lymphocyte Activation/genetics
- Lymphocyte Activation/immunology
- Mice
- Mice, Inbred C57BL
- Mice, Inbred DBA
- Mice, Knockout
- Protein Structure, Tertiary
- Protein Tyrosine Phosphatase, Non-Receptor Type 3/genetics
- Protein Tyrosine Phosphatase, Non-Receptor Type 3/physiology
- Protein Tyrosine Phosphatase, Non-Receptor Type 4/genetics
- Protein Tyrosine Phosphatase, Non-Receptor Type 4/physiology
- Protein Tyrosine Phosphatases/chemistry
- Protein Tyrosine Phosphatases/physiology
- Receptors, Antigen, T-Cell/metabolism
- Receptors, Antigen, T-Cell/physiology
- Signal Transduction/genetics
- Signal Transduction/immunology
- Signal Transduction/physiology
- T-Lymphocytes/physiology
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Affiliation(s)
- Timothy J. Bauler
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, Michigan, United States of America
| | - Wiljan J. A. J. Hendriks
- Department of Cell Biology, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
| | - Philip D. King
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, Michigan, United States of America
- * E-mail:
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13
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Young JA, Becker AM, Medeiros JJ, Shapiro VS, Wang A, Farrar JD, Quill TA, van Huijsduijnen RH, van Oers NS. The protein tyrosine phosphatase PTPN4/PTP-MEG1, an enzyme capable of dephosphorylating the TCR ITAMs and regulating NF-kappaB, is dispensable for T cell development and/or T cell effector functions. Mol Immunol 2008; 45:3756-66. [PMID: 18614237 PMCID: PMC2596642 DOI: 10.1016/j.molimm.2008.05.023] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2008] [Revised: 05/27/2008] [Accepted: 05/28/2008] [Indexed: 11/16/2022]
Abstract
T cell receptor signaling processes are controlled by the integrated actions of families of protein tyrosine kinases (PTKs) and protein tyrosine phosphatases (PTPases). Several distinct cytosolic protein tyrosine phosphatases have been described that are able to negatively regulate TCR signaling pathways, including SHP-1, SHP-2, PTPH1, and PEP. Using PTPase substrate-trapping mutants and wild type enzymes, we determined that PTPN4/PTP-MEG1, a PTPH1-family member, could complex and dephosphorylate the ITAMs of the TCR zeta subunit. In addition, the substrate-trapping derivative augmented basal and TCR-induced activation of NF-kappaB in T cells. To characterize the contribution of this PTPase in T cells, we developed PTPN4-deficient mice. T cell development and TCR signaling events were comparable between wild type and PTPN4-deficient animals. The magnitude and duration of TCR-regulated ITAM phosphorylation, as well as overall protein phosphorylation, was unaltered in the absence of PTPN4. Finally, Th1- and Th2-derived cytokines and in vivo immune responses to Listeria monocytogenes were equivalent between wild type and PTPN4-deficient mice. These findings suggest that additional PTPases are involved in controlling ITAM phosphorylations.
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Affiliation(s)
- Jennifer A. Young
- Department of Immunology, The University of Texas Southwestern Medical Center, Dallas, TX 75390
| | - Amy M. Becker
- Department of Immunology, The University of Texas Southwestern Medical Center, Dallas, TX 75390
| | - Jennifer J. Medeiros
- Department of Immunology, The University of Texas Southwestern Medical Center, Dallas, TX 75390
| | - Virginia S. Shapiro
- Department of Pathology and Laboratory Medicine, University of Pennsylvania, Philadelphia, PA 19104
| | - Andrew Wang
- Department of Immunology, The University of Texas Southwestern Medical Center, Dallas, TX 75390
| | - J. David Farrar
- Department of Immunology, The University of Texas Southwestern Medical Center, Dallas, TX 75390
| | - Timothy A. Quill
- Department of Pharmacology, The University of Texas Southwestern Medical Center, Dallas, TX 75390
| | | | - Nicolai S.C. van Oers
- Department of Immunology, The University of Texas Southwestern Medical Center, Dallas, TX 75390
- Department of Microbiology, The University of Texas Southwestern Medical Center, Dallas, TX 75390
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14
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Kina SI, Tezuka T, Kusakawa S, Kishimoto Y, Kakizawa S, Hashimoto K, Ohsugi M, Kiyama Y, Horai R, Sudo K, Kakuta S, Iwakura Y, Iino M, Kano M, Manabe T, Yamamoto T. Involvement of protein-tyrosine phosphatase PTPMEG in motor learning and cerebellar long-term depression. Eur J Neurosci 2008; 26:2269-78. [PMID: 17953619 DOI: 10.1111/j.1460-9568.2007.05829.x] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Although protein-tyrosine phosphorylation is important for hippocampus-dependent learning, its role in cerebellum-dependent learning remains unclear. We previously found that PTPMEG, a cytoplasmic protein-tyrosine phosphatase expressed in Purkinje cells (PCs), bound to the carboxyl-terminus of the glutamate receptor delta2 via the postsynaptic density-95/discs-large/ZO-1 domain of PTPMEG. In the present study, we generated PTPMEG-knockout (KO) mice, and addressed whether PTPMEG is involved in cerebellar plasticity and cerebellum-dependent learning. The structure of the cerebellum in PTPMEG-KO mice appeared grossly normal. However, we found that PTPMEG-KO mice showed severe impairment in the accelerated rotarod test. These mice also exhibited impairment in rapid acquisition of the cerebellum-dependent delay eyeblink conditioning, in which conditioned stimulus (450-ms tone) and unconditioned stimulus (100-ms periorbital electrical shock) were co-terminated. Moreover, long-term depression at parallel fiber-PC synapses was significantly attenuated in these mice. Developmental elimination of surplus climbing fibers and the physiological properties of excitatory synaptic inputs to PCs appeared normal in PTPMEG-KO mice. These results suggest that tyrosine dephosphorylation events regulated by PTPMEG are important for both motor learning and cerebellar synaptic plasticity.
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Affiliation(s)
- Shin-ichiro Kina
- Division of Oncology, Department of Cancer Biology, Institute of Medical Science, University of Tokyo, Tokyo, 108-8639, Japan
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15
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Bauler TJ, Hughes ED, Arimura Y, Mustelin T, Saunders TL, King PD. Normal TCR signal transduction in mice that lack catalytically active PTPN3 protein tyrosine phosphatase. THE JOURNAL OF IMMUNOLOGY 2007; 178:3680-7. [PMID: 17339465 DOI: 10.4049/jimmunol.178.6.3680] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
PTPN3 (PTPH1) is a cytoskeletal protein tyrosine phosphatase that has been implicated as a negative regulator of early TCR signal transduction and T cell activation. To determine whether PTPN3 functions as a physiological negative regulator of TCR signaling in primary T cells, we generated gene-trapped and gene-targeted mouse strains that lack expression of catalytically active PTPN3. PTPN3 phosphatase-negative mice were born in expected Mendelian ratios and exhibited normal growth and development. Furthermore, numbers and ratios of T cells in primary and secondary lymphoid organs were unaffected by the PTPN3 mutations and there were no signs of spontaneous T cell activation in the mutant mice with increasing age. TCR-induced signal transduction, cytokine production, and proliferation was normal in PTPN3 phosphatase-negative mice. This was observed using both quiescent T cells and recently stimulated T cells where expression of PTPN3 is substantially up-regulated. We conclude, therefore, that the phosphatase activity of PTPN3 is dispensable for negative regulation of TCR signal transduction and T cell activation.
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Affiliation(s)
- Timothy J Bauler
- Department of Microbiology and Immunology, University of Michigan Medical School, 1150 West Medical Center Drive, Ann Arbor, MI 48109, USA
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16
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Gupta R, Chakrabarti P, Dikshit M, Dash D. Late signaling in the activated platelets upregulates tyrosine phosphatase SHP1 and impairs platelet adhesive functions: Regulation by calcium and Src kinase. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2007; 1773:131-40. [PMID: 17046078 DOI: 10.1016/j.bbamcr.2006.08.055] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/09/2006] [Revised: 08/28/2006] [Accepted: 08/30/2006] [Indexed: 10/24/2022]
Abstract
Sustained stimulation of platelets with protease-activated receptor agonists in presence of extracellular calcium was associated with tyrosine dephosphorylation of specific proteins of relative mobilities 35, 67, and 75 kDa. From phosphatase assays and inhibitor studies SHP1, a Src homology 2 (SH2) domain-containing tyrosine phosphatase expressed abundantly in hemopoietic cells, was found to be upregulated in platelets between 25 and 30 min following thrombin stimulation. Concomitantly, SHP1 was tyrosine phosphorylated by, and coprecipitated with, Src tyrosine kinase. SHP1 activation, association with Src and dephosphorylation of specific proteins were dependent on extracellular calcium and maintenance of a higher cytosolic calcium plateau. There was progressive impairment of platelet functions like aggregability and clot retraction, associated with downregulation of fibrinogen-binding affinity of integrin alpha(IIb)beta(3), in the platelets exposed to thrombin for 45 min. This could reflect the late physiological changes in platelets when the cells are consistently exposed to stimulatory signals under thrombogenic environment in vivo.
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Affiliation(s)
- Ramkrishna Gupta
- Department of Biochemistry, Institute of Medical Sciences, Banaras Hindu University, Varanasi-221005, India
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17
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Zhang ZY, Dixon JE. Protein tyrosine phosphatases: mechanism of catalysis and substrate specificity. ADVANCES IN ENZYMOLOGY AND RELATED AREAS OF MOLECULAR BIOLOGY 2006; 68:1-36. [PMID: 8154323 DOI: 10.1002/9780470123140.ch1] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Affiliation(s)
- Z Y Zhang
- Department of Biological Chemistry, Medical School, University of Michigan, Ann Arbor
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18
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Itoh K, Lisovsky M, Hikasa H, Sokol SY. Reorganization of actin cytoskeleton by FRIED, a Frizzled-8 associated protein tyrosine phosphatase. Dev Dyn 2005; 234:90-101. [PMID: 16086323 DOI: 10.1002/dvdy.20526] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Frizzled receptors transduce signals from the extracellular Wnt ligands through multiple signaling pathways that affect cytoskeletal organization and regulate gene expression. Direct intracellular mediators of Frizzled signaling are largely unknown. We identified FRIED (Frizzled interaction and ectoderm defects) by its association with the C-terminal PDZ-binding motif of Xenopus Frizzled 8. FRIED contains an N-terminal KIND domain, a FERM domain, six PDZ domains, and a tyrosine phosphatase domain, being similar in structure to the protein tyrosine phosphatase PTP-BAS/PTP-BL. We report that FRIED proteins with the FERM domain localize to the apical cortex and can inhibit Wnt8-mediated, but not beta-catenin-mediated, secondary axis induction in Xenopus embryos, suggesting a specific interaction with Wnt signaling. A FRIED construct containing the FERM domain induced reorganization of pigment granules and cortical actin in Xenopus ectoderm. Wnt5a suppressed the depigmentation of ectoderm triggered by FRIED, demonstrating that Wnt5a and FRIED functionally interact to regulate the cytoskeletal organization. Our data are consistent with the possibility that FRIED functions by modulating Rac1 activity. We propose that FRIED is an adaptor protein that serves as a molecular link between Wnt signaling and actin cytoskeleton.
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Affiliation(s)
- Keiji Itoh
- Department of Molecular Cell and Developmental Biology, Mount Sinai Medical School, New York, NY 10029, USA
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19
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Rigacci S, Talini D, Berti A. LMW-PTP associates and dephosphorylates STAT5 interacting with its C-terminal domain. Biochem Biophys Res Commun 2004; 312:360-6. [PMID: 14637146 DOI: 10.1016/j.bbrc.2003.10.126] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Hematopoietic cells, particularly megakaryoblastic ones, display a high level of low M(r) phosphotyrosine protein phosphatase (LMW-PTP) expression; nevertheless, the role of this PTP in such cellular lineages has been scarcely investigated. Here, we demonstrate that LMW-PTP is able to associate and dephosphorylate signal transducer and activator of transcription-5 (STAT5) in DAMI megakaryocytic cells. Numerous researchers repeatedly hypothesized the association of a regulatory phosphotyrosine protein phosphatase with STAT5 C-terminus, but such phosphotyrosine protein phosphatase remained unknown. We show evidence indicating that the association of STAT5 and LMW-PTP does not exclusively involve the phosphatase active site and phosphotyrosine residue of STAT5, and we individuate an essential region of interaction at STAT5 C-terminus, coinciding with the previously hypothesized PTP-associating domain.
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Affiliation(s)
- Stefania Rigacci
- Department of Biochemical Sciences, University of Florence, Viale Morgagni 50, Florence 50134, Italy
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20
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Kimber WA, Deak M, Prescott AR, Alessi DR. Interaction of the protein tyrosine phosphatase PTPL1 with the PtdIns(3,4)P2-binding adaptor protein TAPP1. Biochem J 2003; 376:525-35. [PMID: 14516276 PMCID: PMC1223793 DOI: 10.1042/bj20031154] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2003] [Revised: 09/19/2003] [Accepted: 09/29/2003] [Indexed: 12/22/2022]
Abstract
It has been postulated that PtdIns(3,4) P (2), one of the immediate breakdown products of PtdIns(3,4,5) P (3), functions as a signalling molecule in insulin- and growth-factor-stimulated pathways. To date, the t andem- P H-domain-containing p rotein- 1 (TAPP1) and related TAPP2 are still the only known PH-domain-containing proteins that interact strongly and specifically with PtdIns(3,4) P (2). In this study we demonstrate that endogenously expressed TAPP1, is constitutively associated with the protein-tyrosine-phosphatase-like protein-1 (PTPL1 also known as FAP-1). We show that PTPL1 binds to TAPP1 and TAPP2, principally though its first PDZ domain [where PDZ is postsynaptic density protein ( P SD-95)/ Drosophila disc large tumour suppressor ( d lg)/tight junction protein ( Z O1)] and show that this renders PTPL1 capable of associating with PtdIns(3,4) P (2) in vitro. Our data suggest that the binding of TAPP1 to PTPL1 does not influence PTPL1 phosphatase activity, but instead functions to maintain PTPL1 in the cytoplasm. Following stimulation of cells with hydrogen peroxide to induce PtdIns(3,4) P (2) production, PTPL1, complexed to TAPP1, translocates to the plasma membrane. This study provides the first evidence that TAPP1 and PtdIns(3,4) P (2) could function to regulate the membrane localization of PTPL1. We speculate that if PTPL1 was recruited to the plasma membrane by increasing levels of PtdIns(3,4) P (2), it could trigger a negative feedback loop in which phosphoinositide-3-kinase-dependent or other signalling pathways could be switched off by the phosphatase-catalysed dephosphorylation of receptor tyrosine kinases or tyrosine phosphorylated adaptor proteins such as IRS1 or IRS2. Consistent with this notion we observed RNA-interference-mediated knock-down of TAPP1 in HEK-293 cells, enhanced activation and phosphorylation of PKB following IGF1 stimulation.
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Affiliation(s)
- Wendy A Kimber
- MRC Protein Phosphorylation Unit, School of Life Sciences, University of Dundee, Dow Street, Dundee DD1 5EH, Scotland, UK.
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21
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Abstract
The protein tyrosine phosphatase PTP-Basophil (PTP-Bas) and its mouse homologue, PTP-Basophil-like (PTP-BL), are high molecular mass protein phosphatases consisting of a number of diverse protein-protein interaction modules. Several splicing variants of these phosphatases are known to exist thus demonstrating the complexity of these molecules. PTP-Bas/BL serves as a central scaffolding protein facilitating the assembly of a multiplicity of different proteins mainly via five different PDZ domains. Many of these interacting proteins are implicated in the regulation of the actin cytoskeleton. However, some proteins demonstrate a nuclear function of this protein tyrosine phosphatase. PTP-Bas is involved in the regulation of cell surface expression of the cell death receptor, Fas. Moreover, it is a negative regulator of ephrinB phosphorylation, a receptor playing an important role during development. The phosphorylation status of other proteins such as RIL, IkappaBalpha and beta-catenin can also be regulated by this phosphatase. Finally, PTP-BL has been shown to be involved in the regulation of cytokinesis, the last step in cell division. Although the precise molecular function of PTP-Bas/BL is still elusive, current data suggest clearly that PTP-Bas/BL belongs to the family of PDZ domain containing proteins involved in the regulation of the cytoskeleton and of intracellular vesicular transport processes.
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Affiliation(s)
- Kai S Erdmann
- Department of Molecular Neurobiochemistry, Ruhr-University Bochum, Germany.
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22
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Bompard G, Martin M, Roy C, Vignon F, Freiss G. Membrane targeting of protein tyrosine phosphatase PTPL1 through its FERM domain via binding to phosphatidylinositol 4,5-biphosphate. J Cell Sci 2003; 116:2519-30. [PMID: 12766187 DOI: 10.1242/jcs.00448] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
PTPL1 is the largest known cytoplasmic protein tyrosine phosphatase (PTP) containing a FERM (four point-1, ezrin, radixin and moesin) domain. Enzyme localization and PTP-substrate specificity are thought to play crucial roles in the regulation of PTP activity, which determines their functions. Here we report that PTPL1 is predominantly localized at the apical face of plasma membrane enriched in dorsal microvilli when expressed in HeLa cells. By comparing localization of the full-length enzyme with its FERM domain or FERM-deleted PTPL1 construct, we first concluded that PTPL1-FERM domain is necessary and sufficient to address the wild-type enzyme at the membrane. Two potential phosphatidylinositol 4,5-biphosphate [PtdIns(4,5)P2]-binding motifs were identified within the PTPL1-FERM sequence. We further showed that mutation of both sites altered PTPL1 localization similarly to FERM domain deletion, and impaired its subcellular distribution as confirmed biochemically by cell-fractionation experiments. Using protein-lipid overlays, we demonstrated an interaction of the FERM domain of PTPL1 with PtdIns(4,5)P2, which was lost after mutation of potential PtdIns(4,5)P2-binding motifs. Moreover, neomycin, which masks PtdIns(4,5)P2 polar heads, was shown to decrease by 50% the association of PTPL1 with the cytoskeletal fraction. These results identify the crucial role of the FERM domain in PTPL1 intracellular targeting and demonstrate that localization of PTPL1 is regulated by phosphoinositide metabolism.
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Affiliation(s)
- Guillaume Bompard
- Inserm U540, Endocrinologie Moléculaire et Cellulaire des Cancers, Montpellier, France.
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23
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Peters GH, Branner S, Møller KB, Andersen JN, Møller NPH. Enzyme kinetic characterization of protein tyrosine phosphatases. Biochimie 2003; 85:527-34. [PMID: 12763312 DOI: 10.1016/s0300-9084(03)00036-1] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Protein tyrosine phosphatases (PTPs) play a central role in cellular signaling processes, resulting in an increased interest in modulating the activities of PTPs. We therefore decided to undertake a detailed enzyme kinetic evaluation of various transmembrane and cytosolic PTPs (PTPalpha, PTPbeta, PTPepsilon, CD45, LAR, PTP1B and SHP-1), using pNPP as substrate. Most noticeable is the increase in the turnover number for PTPbeta with increasing pH and the weak pH-dependence of the turnover number of CD45. The kinetic data for PTPalpha-D1 and PTPalpha-D1D2 suggest that D2 affects the catalysis of pNPP. PTPepsilon and the closely homologous PTPalpha behave differently. The K(m) data were lower for PTPepsilon than those for PTPalpha, while the inverse was observed for the catalytic efficiencies.
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Affiliation(s)
- Günther H Peters
- Department of Chemistry, Center for Biomembrane Physics (MEMPHYS), Technical University of Denmark, Building 206, DK-2800 Lyngby, Denmark.
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24
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Sun CX, Robb VA, Gutmann DH. Protein 4.1 tumor suppressors: getting a FERM grip on growth regulation. J Cell Sci 2002; 115:3991-4000. [PMID: 12356905 DOI: 10.1242/jcs.00094] [Citation(s) in RCA: 131] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Members of the Protein 4.1 superfamily have highly conserved FERM domains that link cell surface glycoproteins to the actin cytoskeleton. Within this large and constantly expanding superfamily, at least five subgroups have been proposed. Two of these subgroups, the ERM and prototypic Protein 4.1 molecules, include proteins that function as tumor suppressors. The ERM subgroup member merlin/schwannomin is inactivated in the tumor-predisposition syndrome neurofibromatosis 2 (NF2), and the prototypic 4.1 subgroup member, Protein 4.1B, has been implicated in the molecular pathogenesis of breast, lung and brain cancers. This review focuses on what is known of mechanisms of action and critical protein interactions that may mediate the unique growth inhibitory signals of these two Protein 4.1 tumor suppressors. On the basis of insights derived from studying the NF2 tumor suppressor, we propose a model for merlin growth regulation in which CD44 links growth signals from plasma membrane to the nucleus by interacting with ERM proteins and merlin.
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Affiliation(s)
- Chun-Xiao Sun
- Department of Neurology, Washington University School of Medicine, St Louis, MO 63110, USA
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25
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Xiao H, Jepkorir CJ, Harvey K, Remick DG. Thrombin-induced platelet microparticles improved the aggregability of cryopreserved platelets. Cryobiology 2002; 44:179-88. [PMID: 12151273 DOI: 10.1016/s0011-2240(02)00024-x] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Platelets were activated with freezing/thawing and thrombin stimulation, and platelet microparticles generated following platelet activation were isolated with ultracentrifugation. The effects of platelet microparticles on platelet activation were studied with annexin V assay, protein tyrosine phosphorylation, and platelet aggregation. Freezing-induced platelet microparticles decreased but thrombin-induced platelet microparticles increased platelet annexin V binding and aggregation. Freshly washed platelets were cryopreserved using epinephrine and dimethyl sulfoxide (Me(2)SO) as combined cryoprotectants, and stimulated with thrombin-induced platelet microparticles. Following incubation of thrombin-induced platelet microparticles, the reaction time of platelets to agonists decreased but the percentages of aggregation increased, such as washed platelets from 44% +/- 30 to 92% +/- 7, p < 0.001, and cryopreserved platelets from 66% +/- 10 to 77% +/- 7, p < 0.02. By increasing platelet aggregability, platelet microparticles recovered after thrombin stimulation improved platelet function for transfusion. A 53-kDa platelet microparticle protein showed little phosphorylation if it was released from resting platelets or platelets stimulated with ADP, epinephrine, propyl gallate or dephosphorylation if it was derived from ionophore A 23187-stimulated platelets. However, the same protein released from frozen platelets showed significant tyrosine phosphorylation. Since a microparticle protein with 53 kDa was compatible with protein tyrosine phosphatase-1B (PTP-1B), its phosphorylation suggests the inhibition of enzyme activity. The microparticle proteins derived from thrombin-stimulated platelets were significantly phosphorylated at 64 kDa and pp60c-src, suggesting that the activation of tyrosine kinases represents a possible mechanism of thrombin-induced platelet microparticles to improve platelet aggregation.
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Affiliation(s)
- Hongyan Xiao
- Department of Pathology, University of Michigan Medical School, Ann Arbor, MI 48109-0602, USA.
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26
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Uchida Y, Ogata M, Mori Y, Oh-hora M, Hatano N, Hamaoka T. Localization of PTP-FERM in nerve processes through its FERM domain. Biochem Biophys Res Commun 2002; 292:13-9. [PMID: 11890665 DOI: 10.1006/bbrc.2002.6613] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
PTP-FERM is a protein tyrosine phosphatase (PTP) of Caenorhabditis elegans containing a FERM domain and a PDZ domain. Here we report the characterization of PTP-FERM and the essential role of its FERM domain in the localization of PTP-FERM in the worm. There are at least three alternatively spliced PTP-FERM isoforms, all of which contain a band 4.1/FERM domain, a PDZ domain, and a catalytic domain. PTP-FERM possessed phosphatase activity. PTP-FERM was expressed predominantly in neurons in the nerve ring and the ventral nerve cord. PTP-FERM was found in the nerve processes and to be enriched in the peri-membrane region. Studies using various deletion mutants revealed that the FERM domain was essential and sufficient for the subcellular localization. These results suggest the essential role of the FERM domain in the function of PTP-FERM in the neurons of C. elegans.
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Affiliation(s)
- Yohzo Uchida
- Department of Pathology and Pathophysiology, Osaka University Graduate School of Medicine (C6), 2-2 Yamadaoka, Suita, Osaka 565-0871, Japan
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27
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Edwards K, Davis T, Marcey D, Kurihara J, Yamamoto D. Comparative analysis of the Band 4.1/ezrin-related protein tyrosine phosphatase Pez from two Drosophila species: implications for structure and function. Gene 2001; 275:195-205. [PMID: 11587846 DOI: 10.1016/s0378-1119(01)00686-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The FERM-PTPs are a group of proteins that have FERM (Band 4.1, ezrin, radixin, moesin homology) domains at or near their N-termini, and PTP (protein tyrosine phosphatase) domains at their C-termini. Their central regions contain either PSD-95, Dlg, ZO-1 homology domains or putative Src homology 3 domain binding sites. The known FERM-PTPs fall into three distinct classes, which we name BAS, MEG, and PEZ, after representative human PTPs. Here we analyze Pez, a novel gene encoding the single PEZ-class protein present in Drosophila. Pez cDNAs were sequenced from the distantly related flies Drosophila melanogaster and Drosophila silvestris, and found to be highly conserved except in the central region, which contains at least 21 insertions and deletions. Comparison of fly and human Pez reveals several short conserved motifs in the central region that are likely protein binding sites and/or phosphorylation sites. We also identified novel invertebrate members of the BAS and MEG classes using genome data, and generated an alignment of vertebrate and invertebrate FERM domains of each class. 'Specialized' residues were identified that are conserved only within a given class of PTPs. These residues highlight surface regions that may bind class-specific ligands; for PEZ, these residues cluster on and near FERM subdomain F1. Finally, the PTP domain of fly Pez was modeled based on known PTP tertiary structures, and we conclude that Pez is likely a functional phosphatase despite some unusual features of the active site cleft sequences. Biochemical confirmation of this hypothesis and genetic analysis of Pez are currently underway.
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Affiliation(s)
- K Edwards
- Department of Biological Sciences, Illinois State University, Normal, IL 61790-4120, USA.
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28
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Lyons PD, Dunty JM, Schaefer EM, Schaller MD. Inhibition of the catalytic activity of cell adhesion kinase beta by protein-tyrosine phosphatase-PEST-mediated dephosphorylation. J Biol Chem 2001; 276:24422-31. [PMID: 11337490 DOI: 10.1074/jbc.m011080200] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Protein-tyrosine phosphatase (PTP)-PEST is a cytoplasmic tyrosine phosphatase that can bind and dephosphorylate the focal adhesion-associated proteins p130(CAS) and paxillin. Focal adhesion kinase (FAK) and cell adhesion kinase beta (CAKbeta)/PYK2/CADTK/RAFTK are protein-tyrosine kinases that can colocalize with, bind to, and induce tyrosine phosphorylation of p130(CAS) and paxillin. Thus, we considered the possibility that these kinases might be substrates for PTP-PEST. Using a combination of substrate-trapping assays and overexpression of PTP-PEST in mammalian cells, CAKbeta was found to be a substrate for PTP-PEST. Both the major autophosphorylation site of CAKbeta (Tyr(402)) and activation loop tyrosine residues, Tyr(579) and Tyr(580), were targeted for dephosphorylation by PTP-PEST. Dephosphorylation of CAKbeta by PTP-PEST dramatically inhibited CAKbeta kinase activity. In contrast, FAK was a poor substrate for PTP-PEST, and treatment with PTP-PEST had no effect on FAK kinase activity. Tyrosine phosphorylation of paxillin, which is greatly enhanced by CAKbeta overexpression, was dramatically reduced upon coexpression of PTP-PEST. Finally, endogenous PTP-PEST and endogenous CAKbeta were found to localize to similar cellular compartments in epithelial and smooth muscle cells. These results suggest that CAKbeta is a substrate of PTP-PEST and that FAK is a poor PTP-PEST substrate. Further, PTP-PEST can negatively regulate CAKbeta signaling by inhibiting the catalytic activity of the kinase.
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Affiliation(s)
- P D Lyons
- Department of Cell and Developmental Biology and Lineberger Comprehensive Cancer Center, University of North Carolina, Chapel Hill, North Carolina 27599, USA
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29
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Noguchi T, Tsuda M, Takeda H, Takada T, Inagaki K, Yamao T, Fukunaga K, Matozaki T, Kasuga M. Inhibition of cell growth and spreading by stomach cancer-associated protein-tyrosine phosphatase-1 (SAP-1) through dephosphorylation of p130cas. J Biol Chem 2001; 276:15216-24. [PMID: 11278335 DOI: 10.1074/jbc.m007208200] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
SAP-1 (stomach cancer-associated protein-tyrosine phosphatase-1) is a transmembrane-type protein-tyrosine phosphatase that is abundant in the brain and certain cancer cell lines. With the use of a "substrate-trapping" approach, p130(cas), a major focal adhesion-associated phosphotyrosyl protein, has now been identified as a likely physiological substrate of SAP-1. Expression of recombinant SAP-1 induced the dephosphorylation of p130(cas) as well as that of two other components of the integrin-signaling pathway (focal adhesion kinase and p62(dok)) in intact cells. In contrast, expression of a substrate-trapping mutant of SAP-1 induced the hyperphosphorylation of these proteins, indicating a dominant negative effect of this mutant. Overexpression of SAP-1 induced disruption of the actin-based cytoskeleton as well as inhibited various cellular responses promoted by integrin-mediated cell adhesion, including cell spreading on fibronectin, growth factor-induced activation of extracellular signal-regulated kinase 2, and colony formation. Finally, the enzymatic activity of SAP-1, measured with an immunocomplex phosphatase assay, was substantially increased by cell-cell adhesion. These results suggest that SAP-1, by mediating the dephosphorylation of focal adhesion-associated substrates, negatively regulates integrin-promoted signaling processes and, thus, may contribute to contact inhibition of cell growth and motility.
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Affiliation(s)
- T Noguchi
- Second Department of Internal Medicine, Kobe University School of Medicine, 7-5-1 Kusunoki-cho, Chuo-ku, Kobe 650-0017, Japan.
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30
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Jui HY, Tseng RJ, Wen X, Fang HI, Huang LM, Chen KY, Kung HJ, Ann DK, Shih HM. Protein-tyrosine phosphatase D1, a potential regulator and effector for Tec family kinases. J Biol Chem 2000; 275:41124-32. [PMID: 11013262 DOI: 10.1074/jbc.m007772200] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Etk, also named Bmx, is a member of the Tec tyrosine kinase family, which is characterized by a multimodular structure including a pleckstrin homology (PH) domain, an SH3 domain, an SH2 domain, and a catalytic domain. The signaling mechanisms regulating Etk kinase activity remain largely unknown. To identify factor(s) regulating Etk activity, we used the PH domain and a linker region of Etk as a bait for a yeast two-hybrid screen. Three independent clones encoding protein-tyrosine phosphatase D1 (PTPD1) fragments were isolated. The binding of PTPD1 to Etk is specific since PTPD1 cannot associate with either the Akt PH domain or lamin. In vitro and in vivo binding studies demonstrated that PTPD1 can interact with Etk and that residues 726-848 of PTPD1 are essential for this interaction. Deletion analysis of Etk indicated that the PH domain is essential for PTPD1 interaction. Furthermore, the Etk-PTPD1 interaction stimulated the kinase activity of Etk, resulting in an increased phosphotyrosine content in both factors. The Etk-PTPD1 interaction also increased Stat3 activation. The effect of PTPD1 on Etk activation is specific since PTPD1 cannot potentiate Jak2 activity upon Stat3 activation. In addition, Tec (but not Btk) kinase can also be activated by PTPD1. Taken together, these findings indicate that PTPD1 can selectively associate with and stimulate Tec family kinases and modulate Stat3 activation.
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Affiliation(s)
- H Y Jui
- Division of Molecular and Genomic Medicine, National Health Research Institutes, and the Graduate Institute of Life Sciences, National Defense Medical Center, Taipei 11529, Taiwan
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31
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Park KW, Lee EJ, Lee S, Lee JE, Choi E, Kim BJ, Hwang R, Park KA, Baik J. Molecular cloning and characterization of a protein tyrosine phosphatase enriched in testis, a putative murine homologue of human PTPMEG. Gene 2000; 257:45-55. [PMID: 11054567 DOI: 10.1016/s0378-1119(00)00351-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Protein tyrosine phosphorylation is regulated by protein tyrosine kinase and protein tyrosine phosphatase activities. These two counteracting proteins are implicated in cell growth and transformation. Using polymerase chain reaction with degenerate primers, we have identified a novel mouse protein tyrosine phosphatase (PTP). This cDNA contains a single open reading frame of the predicted 926 amino acids. Those predicted amino acids showed significant identity with human megakaryocyte protein-tyrosine phosphatase by 91% in nucleotide sequences and 94% in amino acid sequences. We have identified that expression of this PTP is highly enriched in the testis in mouse and human and has been termed here as a 'testis-enriched phosphatase' (TEP). Northern analysis detected two mRNA species of 3.7 and 3.2kb for this PTP in mouse testis and the expression of TEP is regulated during development. The recombinant phosphatase domain possesses protein tyrosine phosphatase activity when expressed in Escherichia coli. Immunohistochemical analysis of the cellular localization of TEP on mouse testis sections showed that this PTP is specifically expressed in spermatocytes and spermatids within seminiferous tubules, suggesting an important role in spermatogenesis.
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MESH Headings
- Amino Acid Sequence
- Animals
- Base Sequence
- Blotting, Northern
- Cloning, Molecular
- DNA, Complementary/chemistry
- DNA, Complementary/genetics
- Female
- Gene Expression Regulation, Developmental
- Gene Expression Regulation, Enzymologic
- Humans
- Immunohistochemistry
- Male
- Megakaryocytes/cytology
- Megakaryocytes/enzymology
- Mice
- Molecular Sequence Data
- Protein Tyrosine Phosphatases/genetics
- Protein Tyrosine Phosphatases/metabolism
- RNA, Messenger/genetics
- RNA, Messenger/metabolism
- Sequence Alignment
- Sequence Analysis, DNA
- Sequence Homology, Amino Acid
- Testis/enzymology
- Testis/growth & development
- Tissue Distribution
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Affiliation(s)
- K W Park
- Laboratory of Molecular Biology, Medical Research Center, Brain Korea 21 Project for Medical Sciences, College of Medicine, Yonsei University, 120-752, Seoul, South Korea
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32
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Ort T, Maksimova E, Dirkx R, Kachinsky AM, Berghs S, Froehner SC, Solimena M. The receptor tyrosine phosphatase-like protein ICA512 binds the PDZ domains of beta2-syntrophin and nNOS in pancreatic beta-cells. Eur J Cell Biol 2000; 79:621-30. [PMID: 11043403 DOI: 10.1078/0171-9335-00095] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Islet cell autoantigen (ICA) 512 of type I diabetes is a receptor tyrosine phosphatase-like protein associated with the secretory granules of neurons and endocrine cells including insulin-secreting beta-cells of the pancreas. Here we show that in a yeast two-hybrid assay its cytoplasmic domain binds beta2-syntrophin, a modular adapter which in muscle cells interacts with members of the dystrophin family including utrophin, as well as the signaling molecule neuronal nitric oxide synthase (nNOS). The cDNA isolated by two-hybrid screening corresponded to a novel beta2-syntrophin isoform with a predicted molecular mass of 28 kDa. This isoform included the PDZ domain, but not the C-terminal region, which in full-length beta2-syntrophin is responsible for binding dystrophin-related proteins. In vitro binding of the beta2-syntrophin PDZ domain to ICA512 required both ICA512's C-terminal region and an internal polypeptide preceding its tyrosine phosphatase-like domain. Immunomicroscopy and co-immunoprecipitations from insulinoma INS-1 cells confirmed the occurrence of ICA512-beta2-syntrophin complexes in vivo. ICA512 also interacted in vitro with the PDZ domain of nNOS and ICA512-nNOS complexes were co-immunoprecipitated from INS-1 cells. Finally, we show that INS-1 cells, like muscle cells, contain beta2-syntrophin-utrophin oligomers. Thus, we propose that ICA512, through beta2-syntrophin and nNOS, links secretory granules with the actin cytoskeleton and signaling pathways involving nitric oxide.
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Affiliation(s)
- T Ort
- Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut 06510, USA
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33
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Warabi M, Nemoto T, Ohashi K, Kitagawa M, Hirokawa K. Expression of protein tyrosine phosphatases and its significance in esophageal cancer. Exp Mol Pathol 2000; 68:187-95. [PMID: 10816386 DOI: 10.1006/exmp.2000.2303] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Expression of mRNA protein tyrosine phosphatases (PTPs) was surveyed in an esophageal cancer cell line by RT-PCR using degenerate primers. The mRNAs for eight kinds of PTPs were expressed in the cell line. We examined mRNA expression of these PTPs in 12 cases of esophageal cancer by Northern analysis. Significant signals were obtained for three kinds of PTPs, PTP1B, PTPH1, and PTPD1. The magnitude of expression of each PTP was measured as the ratio of the signal intensity of each PTP to that of a control gene (NADPH), and the ratio was then compared to normal mucosa around the cancer lesion. Among the three kinds of PTPs, the expression of PTP1B mRNA was significantly depressed in cancer lesions compared with that in the surrounding normal mucosa. In contrast, the expression of PTPH1 mRNA was significantly increased in cancer lesions compared with that in normal mucosa. PTPD1 did not show any significant trend in comparisons of cancer and surrounding normal mucosa. The results suggest that PTP1B and PTPH1 are engaged in opposing signaling pathways, the tumor-suppressive and tumor-promoting pathways, respectively, in esophageal carcinogenesis.
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MESH Headings
- Adult
- Aged
- Carcinoma, Squamous Cell/enzymology
- Carcinoma, Squamous Cell/genetics
- Carcinoma, Squamous Cell/pathology
- Cell Differentiation
- DNA, Complementary/genetics
- Enzyme Induction
- Esophageal Neoplasms/enzymology
- Esophageal Neoplasms/genetics
- Esophageal Neoplasms/pathology
- Female
- Gene Expression Regulation, Neoplastic
- Humans
- Lymphatic Metastasis
- Male
- Middle Aged
- Mucous Membrane/enzymology
- Neoplasm Invasiveness
- Neoplasm Proteins/biosynthesis
- Neoplasm Proteins/genetics
- Neoplasm Proteins/physiology
- Protein Tyrosine Phosphatase, Non-Receptor Type 1
- Protein Tyrosine Phosphatase, Non-Receptor Type 3
- Protein Tyrosine Phosphatases/biosynthesis
- Protein Tyrosine Phosphatases/deficiency
- Protein Tyrosine Phosphatases/genetics
- Protein Tyrosine Phosphatases/physiology
- Protein Tyrosine Phosphatases, Non-Receptor
- RNA, Messenger/biosynthesis
- RNA, Neoplasm/biosynthesis
- Tumor Cells, Cultured
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Affiliation(s)
- M Warabi
- Department of Pathology and Immunology, School of Medicine, Tokyo Medical and Dental University, Tokyo, 113-8519, Japan
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34
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Hironaka K, Umemori H, Tezuka T, Mishina M, Yamamoto T. The protein-tyrosine phosphatase PTPMEG interacts with glutamate receptor delta 2 and epsilon subunits. J Biol Chem 2000; 275:16167-73. [PMID: 10748123 DOI: 10.1074/jbc.m909302199] [Citation(s) in RCA: 85] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Glutamate receptor (GluR) delta2 is selectively expressed in cerebellar Purkinje cells and plays a crucial role in cerebellum-dependent motor learning. Although GluRdelta2 belongs to an ionotropic GluR family, little is known about its pharmacological features and downstream signaling cascade. To study molecular mechanisms underlying GluRdelta2-dependent motor learning, we employed yeast two-hybrid screening to isolate GluRdelta2-interacting molecules and identified protein-tyrosine phosphatase PTPMEG. PTPMEG is a family member of band 4.1 domain-containing protein-tyrosine phosphatases and is expressed prominently in brain. Here, we showed by in situ hybridization analysis that the PTPMEG mRNA was enriched in mouse thalamus and Purkinje cells. We also showed that PTPMEG interacted with GluRdelta2 as well as with N-methyl-d-aspartate receptor GluRepsilon1 in cultured cells and in brain. PTPMEG bound to the putative C-terminal PDZ target sequence of GluRdelta2 and GluRepsilon1 via its PDZ domain. Examination of the effect of PTPMEG on tyrosine phosphorylation of GluRepsilon1 unexpectedly revealed that PTPMEG enhanced Fyn-mediated tyrosine phosphorylation of GluRepsilon1 in its PTPase activity-dependent manner. Thus, we conclude that PTPMEG associates directly with GluRdelta2 and GluRepsilon1. Moreover, our data suggest that PTPMEG plays a role in signaling downstream of the GluRs and/or in regulation of their activities through tyrosine dephosphorylation.
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Affiliation(s)
- K Hironaka
- Department of Oncology, Institute of Medical Science, University of Tokyo, Minato-ku, Tokyo 108-8639, Japan
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35
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Aoyama K, Matsuda T, Aoki N. Characterization of newly identified four isoforms for a putative cytosolic protein tyrosine phosphatase PTP36. Biochem Biophys Res Commun 1999; 266:523-31. [PMID: 10600535 DOI: 10.1006/bbrc.1999.1845] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
In the course of determining the expression profiles of protein tyrosine phosphatases in lactating mammary gland, we found the expression of an isoform for a putative cytosolic and cytoskeleton-associated protein tyrosine phosphatase PTP36. Further detailed RT-PCR and Northern blot analyses revealed the expression of several isoforms for PTP36 in a tissue-dependent manner. We have cloned the cDNAs encoding four truncated isoforms for PTP36 and designated PTP36-A, -B, -C, and -D, respectively. PTP36-A and -C had new sequences generated due to frameshift, whereas PTP36-B and -D were in-frame variants. Gly- and Glu-rich domains and a putative PTP domain were missing from PTP36-A, but the band 4.1 domain remained. PTP36-B retained the band 4.1 and PTP domains but lacked Pro-, Gly- and Glu-rich domains. Most domain structures were lacking in PTP36-C and -D. Interestingly, PTP36-C contained an incomplete band 4.1 domain, but the newly created sequence exhibited high homology to human nebulette, which was also suggested to associate with cytoskeletons. When transiently expressed in COS7 and HEK293 cells, not only the wild type but also all the isoforms were recovered in Triton X-100-insoluble cytoskeleton-associated fractions and this distribution was not affected by mechanical cell detachment and treatment with a kinase inhibitor staurosporine. Such cellular distribution of PTP36 was also observed in stable COS7 clones. Further studies using deletion mutants suggested that the first 30 amino acids as well as the band 4.1 domain of PTP36 were involved in association with Triton X-100 insoluble cytoskeletons. Tissue-dependent expression and deletion in domain structures might reflect the biological significance of the isoforms for PTP36 in certain physiological conditions.
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Affiliation(s)
- K Aoyama
- Graduate School of Bioagricultural Sciences, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, 464-8601, Japan
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36
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Irie S, Hachiya T, Rabizadeh S, Maruyama W, Mukai J, Li Y, Reed JC, Bredesen DE, Sato TA. Functional interaction of Fas-associated phosphatase-1 (FAP-1) with p75(NTR) and their effect on NF-kappaB activation. FEBS Lett 1999; 460:191-8. [PMID: 10544233 DOI: 10.1016/s0014-5793(99)01324-1] [Citation(s) in RCA: 64] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
The common neurotrophin receptor p75(NTR), a member of the tumor necrosis factor (TNF) receptor superfamily, plays an important role in several cellular signaling cascades, including that leading to apoptosis. FAP-1 (Fas-associated phosphatase-1), which binds to the cytoplasmic tail of Fas, was originally identified as a negative regulator of Fas-mediated apoptosis. Here we have shown by co-immunoprecipitation that FAP-1 also binds to the p75(NTR) cytoplasmic domain in vivo through the interaction between the third PDZ domain of FAP-1 and C-terminal Ser-Pro-Val residues of p75(NTR). Furthermore, cells expressing a FAP-1/green fluorescent protein showed intracellular co-localization of FAP-1 and p75(NTR) at the plasma membrane. To elucidate the functional role of this physical interaction, we examined TRAF6 (TNF receptor-associated factor 6)-mediated NF-kappaB activation and tamoxifen-induced apoptosis in 293T cells expressing p75(NTR). The results revealed that TRAF6-mediated NF-kappaB activation was suppressed by p75(NTR) and that the p75(NTR)-mediated NF-kappaB suppression was reduced by FAP-1 expression. Interestingly, a mutant of the p75(NTR) intracellular domain with a single substitution of a Met for Val in its C-terminus, which cannot interact with FAP-1, displayed enhanced pro-apoptotic activity in 293T transfected cells. Thus, similar to Fas, FAP-1 may be involved in suppressing p75(NTR)-mediated pro-apoptotic signaling through its interaction with three C-terminal amino acids (tSPV). Thus, FAP-1 may regulate p75(NTR)-mediated signal transduction by physiological interaction through its third PDZ domain.
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Affiliation(s)
- S Irie
- Molecular Oncology Laboratory, Tsukuba Life Science Center, Institute of Physical and Chemical Research (RIKEN), Ibaraki, Japan.
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37
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Mustelin T, Brockdorff J, Rudbeck L, Gjörloff-Wingren A, Han S, Wang X, Tailor P, Saxena M. The next wave: protein tyrosine phosphatases enter T cell antigen receptor signalling. Cell Signal 1999; 11:637-50. [PMID: 10530872 DOI: 10.1016/s0898-6568(99)00016-9] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Recent years have seen an exponentially increasing interest in the molecular mechanisms of signal transduction. Much of the focus has been on protein tyrosine kinase-mediated signalling, while the study of protein tyrosine phosphatases has lagged behind. We predict that the phosphatases will become a "hot topic" in the field within the next few years. This review summarizes the current state-of-the-art in our understanding of the structure, regulation and role of protein tyrosine phosphatases in T lymphocyte activation.
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Affiliation(s)
- T Mustelin
- Division of Cell Biology, La Jolla Institute for Allergy and Immunology, San Diego, CA 92121, USA.
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38
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Hermel JM, Dirkx R, Solimena M. Post-translational modifications of ICA512, a receptor tyrosine phosphatase-like protein of secretory granules. Eur J Neurosci 1999; 11:2609-20. [PMID: 10457160 DOI: 10.1046/j.1460-9568.1999.00677.x] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
The autoantigen of type I diabetes ICA512 is a receptor tyrosine phosphatase-like protein enriched in the secretory granule membranes of neurons and peptide secreting endocrine cells. While the function of ICA512 remains unknown, it is thought to link regulated neuropeptide and peptide hormone secretion with signal transduction pathways involving tyrosine phosphorylation/dephosphorylation. To characterize further its biochemical properties, we conducted studies in the bovine pituitary, an abundant source of native ICA512, as well as in fibroblasts transfected with various human ICA512 cDNA constructs. Based on these studies we have established that the signal peptide of ICA512 encompasses residues 1-34 and that the ectodomain of ICA512 undergoes multiple post-translation modifications, including N-glycosylation. Newly synthesized ICA512 appears first as a pro-protein of 110 kDa that is then converted by post-translational modifications into a 130-kDa species. Cleavage of pro-ICA512 at a consensus for furin-like convertases generates a 60-66-kDa ICA512 transmembrane fragment (amino acids 449-979). Such processing ICA512 is not restricted to neuroendocrine cells, as it can also occur in transfected fibroblasts. Finally, the predicted N-terminal fragment of ICA512 resulting from this cleavage (amino acids 35-448) or parts thereof are present in the neurosecretosomes of posterior pituitary, raising the possibility that they may be secreted upon exocytosis of secretory granules.
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Affiliation(s)
- J M Hermel
- Department of Internal Medicine, Section of Endocrinology, Yale University School of Medicine, New Haven, CT 06520-8020, USA
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39
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Murthy KK, Clark K, Fortin Y, Shen SH, Banville D. ZRP-1, a zyxin-related protein, interacts with the second PDZ domain of the cytosolic protein tyrosine phosphatase hPTP1E. J Biol Chem 1999; 274:20679-87. [PMID: 10400701 DOI: 10.1074/jbc.274.29.20679] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Protein-protein interactions play an important role in the specificity of cellular signaling cascades. By using the yeast two-hybrid system, a specific interaction was identified between the second PDZ domain of the cytosolic protein tyrosine phosphatase hPTP1E and a novel protein, which was termed ZRP-1 to indicate its sequence similarity to the Zyxin protein family. The mRNA encoding this protein is distributed widely in human tissues and contains an open reading frame of 1428 base pairs, predicting a polypeptide of 476 amino acid residues. The deduced protein displays a proline-rich amino-terminal region and three double zinc finger LIM domains at its carboxyl terminus. The specific interaction of this novel protein with the second PDZ domain of hPTP1E was demonstrated both in vitro, using bacterially expressed proteins, and in vivo, by co-immunoprecipitation studies. Deletion analysis indicated that an intact carboxyl terminus is required for its interaction with the second PDZ domain of hPTP1E in the yeast two-hybrid system and suggested that other sequences, including the LIM domains, also participate in the interaction. The genomic organization of the ZRP-1 coding sequence is identical to that of the lipoma preferred partner gene, another Zyxin-related protein, suggesting that the two genes have evolved from a recent gene duplication event.
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Affiliation(s)
- K K Murthy
- Pharmaceutical Biotechnology Sector, Biotechnology Research Institute, Montreal, Quebec H4P 2R2, Canada
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40
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Ogata M, Takada T, Mori Y, Uchida Y, Miki T, Okuyama A, Kosugi A, Sawada M, Oh-hora M, Hamaoka T. Regulation of phosphorylation level and distribution of PTP36, a putative protein tyrosine phosphatase, by cell-substrate adhesion. J Biol Chem 1999; 274:20717-24. [PMID: 10400706 DOI: 10.1074/jbc.274.29.20717] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Recently we have cloned a putative protein tyrosine phosphatase, PTP36/PTPD2/pez, which possesses a domain homologous to the N-terminal half of band 4.1 protein. In mouse fibroblasts adhered to substrates, PTP36 was phosphorylated on serine residues. PTP36 was found to make complexes with serine/threonine kinase(s), which phosphorylated PTP36 in vitro. PTP36 was dephosphorylated rapidly when the cell-substrate adhesion was disrupted and it was phosphorylated again along with the reattachment of the cells to fibronectin. Rephosphorylation of PTP36 seemed to depend on actin polymerization since it was inhibited by cytochalasin D. The cell detachment also induced the translocation of PTP36 into the membrane-associated cytoskeletal fraction. Staurosporine and ML-9, which inhibited the phosphorylation of PTP36 in vivo, induced the translocation of PTP36 too. On the contrary, when the dephosphorylation of PTP36 was inhibited by okadaic acid, no translocation of PTP36 was induced by the cell detachment. These results demonstrate that the cell-substrate adhesion and cell spreading regulates the intracellular localization of PTP36 most likely through its phosphorylation and therefore, PTP36 may play important roles in the signal transduction pathway of cell-adhesion.
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Affiliation(s)
- M Ogata
- Department of Oncology, Biomedical Research Center, Osaka University Medical School, Suita, Osaka 565-0871, Japan.
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41
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Hernández-Hernández A, Llanillo M, Rodríguez MC, Gómez F, Sánchez-Yagüe J. Amphiphilic and hydrophilic nature of sheep and human platelet phosphotyrosine phosphatase forms. BIOCHIMICA ET BIOPHYSICA ACTA 1999; 1419:195-206. [PMID: 10407071 DOI: 10.1016/s0005-2736(99)00066-8] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
To date, although at least 75 different PTPases (protein-tyrosine-phosphate-phosphohydrolase, EC 3.1.3.48) have been identified, those detected in platelets are rather scarce. Based on previous results from our laboratory, we investigated the existence of new PTPases in platelets. Triton X-114 phase partitioning of Triton X-100-solubilized human and sheep platelet membranes allowed PTPase to be recovered in the detergent-rich (40-35%, respectively) and -poor phases (60-65%, respectively). Sedimentation analyses of both phases from the sheep species revealed hydrophilic 6S and 3.7S, and amphiphilic 7.5S and 10.3S PTPase forms. Sedimentation analyses of human platelet membrane-associated or cytosolic PTPase revealed hydrophilic 6.7S and 4.3S, and amphiphilic 5.5S and 10.8S forms, or hydrophilic 4S, 5.9S and 6.9S forms, respectively. Western blot analysis using monoclonal antibodies (MoAb) against human PTP1B, PTP1C, PTP1D and RPTPalpha (mouse anti-human PTPase MoAbs) showed that RPTPalpha was not present in platelets and that the PTP1C type and PTP1D type (but probably not the PTP1B type) were expressed in sheep species. Immunoblots also revealed that all PTPases detected were mainly membrane-associated, with similar percentages of cellular distribution in both species. All PTPases were mainly recovered in the detergent-poor phases from the Triton X-114 phase partitioning, although PTP1D from human species was also significantly present (30%) in the detergent-rich phase. Additionally, all PTPases sedimented within the same PTPase peak in sucrose gradients (sedimentation coefficients around 4S). These findings indicate that amphiphilic and hydrophilic PTPases different from PTP1B, PTP1C, PTP1D or RPTPalpha, with higher sedimentation coefficients and with higher activity when O-phosphotyrosine or a synthetic peptide phosphorylated on tyrosine were used as substrates, are present in platelets.
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Affiliation(s)
- A Hernández-Hernández
- Departamento de Bioquímica y Biología Molecular, Universidad de Salamanca, Edificio Departamental (Laboratorio 106), Plaza Doctores de la Reina s/n, E-37007, Salamanca, Spain
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42
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Zhang SH, Liu J, Kobayashi R, Tonks NK. Identification of the cell cycle regulator VCP (p97/CDC48) as a substrate of the band 4.1-related protein-tyrosine phosphatase PTPH1. J Biol Chem 1999; 274:17806-12. [PMID: 10364224 DOI: 10.1074/jbc.274.25.17806] [Citation(s) in RCA: 86] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The human band 4.1-related protein-tyrosine phosphatase PTPH1 was introduced into NIH3T3 cells under the control of a tetracycline-repressible promoter. Ectopic expression of wild type PTPH1 dramatically inhibited cell growth, whereas a catalytically impaired mutant showed no effect. To identify the direct target of PTPH1 in the cell, we generated a substrate-trapping mutant, in which an invariant aspartate residue was changed to alanine (D811A in PTPH1). The PTPH1-D811A mutant trapped primarily a 97-kDa tyrosine-phosphorylated protein, which was determined to be VCP (also named p97 or yeast CDC48), from various cell lysates in vitro. However, when expressed in mammalian cells, the D811A mutant was observed to contain high levels of phosphotyrosine and did not trap substrates. Mutation of tyrosine 676 to phenylalanine (Y676F) in the PTPH1-D811A mutant led to a marked reduction in phosphotyrosine content. Furthermore, this double mutant specifically trapped VCP in vivo and recognized the C-terminal tyrosines of VCP, whose phosphorylation is important for cell cycle progression in yeast. Like wild type PTPH1, this double mutant also inhibited cell proliferation. Moreover, induction of wild type PTPH1 resulted in specific dephosphorylation of VCP without changing the overall phosphotyrosine profile of the cells. VCP has been implicated in control of a variety of membrane functions, including membrane fusions, and is a regulator of the cell cycle. Our results suggest that PTPH1 may exert its effects on cell growth through dephosphorylation of VCP, thus implicating tyrosine phosphorylation as an important regulator of VCP function.
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Affiliation(s)
- S H Zhang
- Cold Spring Harbor Laboratory, Cold Spring Harbor, New York 11724, USA
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43
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Ogata M, Takada T, Mori Y, Oh-hora M, Uchida Y, Kosugi A, Miyake K, Hamaoka T. Effects of overexpression of PTP36, a putative protein tyrosine phosphatase, on cell adhesion, cell growth, and cytoskeletons in HeLa cells. J Biol Chem 1999; 274:12905-9. [PMID: 10212280 DOI: 10.1074/jbc.274.18.12905] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Non-receptor-type putative protein tyrosine phosphatase-36 (PTP36), also known as PTPD2/Pez, possesses a domain homologous to the N-terminal half of band 4.1 protein. To gain insight into the biological function of PTP36, we established a HeLa cell line, HtTA/P36-9, in which the overexpression of PTP36 was inducible. PTP36 expressed in HeLa cells was enriched in the cytoskeleton near the plasma membrane. There was little endogenous PTP36 detectable in uninduced HtTA/P36-9 cells or in the parental HeLa cells. Upon induction of PTP36 overexpression, HtTA/P36-9 cells spread less well, grew more slowly, and adhered to the extracellular matrix proteins less well than uninduced cells. Moreover, decreases in the actin stress fibers and the number of focal adhesions were observed. The tyrosine phosphorylation of the focal adhesion kinase induced by lysophosphatidic acid was suppressed in the HtTA/P36-9 cells overexpressing PTP36. These results indicate that PTP36 affects cytoskeletons, cell adhesion, and cell growth, thus suggesting that PTP36 is involved in their regulatory processes.
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Affiliation(s)
- M Ogata
- Department of Oncology, Biomedical Research Center, Osaka University Medical School, Suita, Osaka 565-0871, Japan.
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44
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Abstract
Protein tyrosine phosphatases act in conjunction with protein kinases to regulate the tyrosine phosphorylation events that control cell activation and differentiation. We have isolated a previously undescribed human phosphatase, Lyp, that encodes an intracellular 105-kD protein containing a single tyrosine phosphatase catalytic domain. The noncatalytic domain contains four proline-rich potential SH3 domain binding sites and an NXXY motif that, if phosphorylated, may be recognized by phosphotyrosine binding (PTB) domains. Comparison of the Lyp amino acid sequence with other known proteins shows 70% identity with the murine phosphatase PEP. The human Lyp gene was localized to chromosome 1p13 by fluorescence in situ hybridization analysis. We also identified an alternative spliced form of Lyp RNA, Lyp2. This isoform encodes a smaller 85-kD protein with an alternative C-terminus. The lyp phosphatases are predominantly expressed in lymphoid tissues and cells, with Lyp1 being highly expressed in thymocytes and both mature B and T cells. Increased Lyp1 expression can be induced by activation of resting peripheral T lymphocytes with phytohemagglutinin or anti-CD3. Lyp1 was found to be constitutively associated with the proto-oncogene c-Cbl in thymocytes and T cells. Overexpression of lyp1 reduces Cbl tyrosine phosphorylation, suggesting that it may be a substrate of the phosphatase. Thus, Lyp may play a role in regulating the function of Cbl and its associated protein kinases.
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Girault JA, Labesse G, Mornon JP, Callebaut I. Janus Kinases and Focal Adhesion Kinases Play in the 4.1 Band: A Superfamily of Band 4.1 Domains Important for Cell Structure and Signal Transduction. Mol Med 1998. [DOI: 10.1007/bf03401769] [Citation(s) in RCA: 47] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022] Open
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Girault JA, Labesse G, Mornon JP, Callebaut I. Janus kinases and focal adhesion kinases play in the 4.1 band: a superfamily of band 4.1 domains important for cell structure and signal transduction. Mol Med 1998; 4:751-69. [PMID: 9990861 PMCID: PMC2230389] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/10/2023] Open
Abstract
The band 4.1 domain was first identified in the red blood cell protein band 4.1, and subsequently in ezrin, radixin, and moesin (ERM proteins) and other proteins, including tumor suppressor merlin/schwannomin, talin, unconventional myosins VIIa and X, and protein tyrosine phosphatases. Recently, the presence of a structurally related domain has been demonstrated in the N-terminal region of two groups of tyrosine kinases: the focal adhesion kinases (FAK) and the Janus kinases (JAK). Additional proteins containing the 4.1/JEF (JAK, ERM, FAK) domain include plant kinesin-like calmodulin-binding proteins (KCBP) and a number of uncharacterized open reading frames identified by systematic DNA sequencing. Phylogenetic analysis of amino acid sequences suggests that band 4.1/JEF domains can be grouped in several families that have probably diverged early during evolution. Hydrophobic cluster analysis indicates that the band 4.1/JEF domains might consist of a duplicated module of approximately 140 residues and a central hinge region. A conserved property of the domain is its capacity to bind to the membrane-proximal region of the C-terminal cytoplasmic tail of proteins with a single transmembrane segment. Many proteins with band 4.1/JEF domains undergo regulated intra- or intermolecular homotypic interactions. Additional properties common to band 4.1/JEF domains of several proteins are binding of phosphoinositides and regulation by GTPases of the Rho family. Many proteins with band 4. 1/JEF domains are associated with the actin-based cytoskeleton and are enriched at points of contact with other cells or the extracellular matrix, from which they can exert control over cell growth. Thus, proteins with band 4.1/JEF domain are at the crossroads between cytoskeletal organization and signal transduction in multicellular organisms. Their importance is underlined by the variety of diseases that can result from their mutations.
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Affiliation(s)
- J A Girault
- INSERM U114, Collège de France, Paris, France.
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47
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The 30-kD Domain of Protein 4.1 Mediates Its Binding to the Carboxyl Terminus of pICln, a Protein Involved in Cellular Volume Regulation. Blood 1998. [DOI: 10.1182/blood.v92.4.1442.416k14_1442_1447] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Erythrocyte protein 4.1 (P4.1) is an 80-kD cytoskeletal protein that is important for the maintenance of the structural integrity and flexibility of the red blood cell membrane. Limited chymotryptic digestion of erythroid P4.1 yields 4 structural domains corresponding to the 30-, 16-, 10-, and 22/24-kD domains. Using a yeast two-hybrid system, we isolated cDNA clones encoding pICln that specifically interacts with the 30-kD domain of P4.1. In this report, we show that the carboxyl-terminus (amino acid residues 103-237) of pICln binds to the 30-kD domain of P4.1 in a yeast two-hybrid system. The direct association between the 30-kD domain of P4.1 and pICln was further confirmed by the following findings: (1) the S35-methione–labeled pICln specifically bound to both GST/P4.1-80 (80 kD) and GST/P4.1-30 (30 kD) fusion proteins, but not to the proteins that lack the 30-kD domain; (2) coimmunoprecipitation analysis of the cell extracts from transfected SiHa cells showed that pICln and P4.1 associate in transfected cells. It was reported that pICln can form a complex with actin and may play a role involved in cellular volume regulation. The direct association between P4.1 and pICln suggests that pICln may link P4.1-bound cytoskeletal elements to an unidentified volume-sensitive chloride channel.© 1998 by The American Society of Hematology.
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48
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The 30-kD Domain of Protein 4.1 Mediates Its Binding to the Carboxyl Terminus of pICln, a Protein Involved in Cellular Volume Regulation. Blood 1998. [DOI: 10.1182/blood.v92.4.1442] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
AbstractErythrocyte protein 4.1 (P4.1) is an 80-kD cytoskeletal protein that is important for the maintenance of the structural integrity and flexibility of the red blood cell membrane. Limited chymotryptic digestion of erythroid P4.1 yields 4 structural domains corresponding to the 30-, 16-, 10-, and 22/24-kD domains. Using a yeast two-hybrid system, we isolated cDNA clones encoding pICln that specifically interacts with the 30-kD domain of P4.1. In this report, we show that the carboxyl-terminus (amino acid residues 103-237) of pICln binds to the 30-kD domain of P4.1 in a yeast two-hybrid system. The direct association between the 30-kD domain of P4.1 and pICln was further confirmed by the following findings: (1) the S35-methione–labeled pICln specifically bound to both GST/P4.1-80 (80 kD) and GST/P4.1-30 (30 kD) fusion proteins, but not to the proteins that lack the 30-kD domain; (2) coimmunoprecipitation analysis of the cell extracts from transfected SiHa cells showed that pICln and P4.1 associate in transfected cells. It was reported that pICln can form a complex with actin and may play a role involved in cellular volume regulation. The direct association between P4.1 and pICln suggests that pICln may link P4.1-bound cytoskeletal elements to an unidentified volume-sensitive chloride channel.© 1998 by The American Society of Hematology.
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Dorner C, Ciossek T, Müller S, Møller PH, Ullrich A, Lammers R. Characterization of KIF1C, a new kinesin-like protein involved in vesicle transport from the Golgi apparatus to the endoplasmic reticulum. J Biol Chem 1998; 273:20267-75. [PMID: 9685376 DOI: 10.1074/jbc.273.32.20267] [Citation(s) in RCA: 106] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Kinesins comprise a large family of microtubule-based motor proteins, of which individual members mediate specific types of motile processes. Using the ezrin domain of the protein-tyrosine phosphatase PTPD1 as a bait in a yeast two-hybrid screen, we identified a new kinesin-like protein, KIF1C. KIF1C represents a member of the Unc104 subfamily of kinesin-like proteins that are involved in the transport of mitochondria or synaptic vesicles in axons. Like its homologues, the 1103-amino acid protein KIF1C consists of an amino-terminal motor domain followed by a U104 domain and probably binds to target membranes through carboxyl-terminal sequences. Interestingly, KIF1C was tyrosine-phosphorylated after peroxovanadate stimulation when overexpressed in 293 or NIH3T3 fibroblasts or in native C2C12 cells. Using immunofluorescence, we found that KIF1C is localized primarily at the Golgi apparatus. In brefeldin A-treated cells, the Golgi membranes and KIF1C redistributed to the endoplasmic reticulum (ER). This brefeldin A-induced flow of Golgi membranes into the ER was inhibited in cells transiently overexpressing catalytically inactive KIF1C. In conclusion, our data suggest an involvement of tyrosine phosphorylation in the regulation of the Golgi to ER membrane flow and describe a new kinesin-like motor protein responsible for this transport.
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Affiliation(s)
- C Dorner
- Department of Molecular Biology, Max-Planck Institut für Biochemie, Am Klopferspitz 18a, 82152 Martinsried, Germany
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Pasquet JM, Dachary-Prigent J, Nurden AT. Microvesicle release is associated with extensive protein tyrosine dephosphorylation in platelets stimulated by A23187 or a mixture of thrombin and collagen. Biochem J 1998; 333 ( Pt 3):591-9. [PMID: 9677317 PMCID: PMC1219621 DOI: 10.1042/bj3330591] [Citation(s) in RCA: 65] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Phosphatidylserine exposure and microvesicle release give rise to procoagulant activity during platelet activation. We have previously shown that whereas the Ca2+ ionophore A23187 and 2,5-di-(t-butyl)-1, 4-benzohydroquinone, a Ca2+-ATPase inhibitor, induce phosphatidylserine exposure, only the former triggers microvesicle release. We now report that microvesicle formation with ionophore A23187 is specifically associated with mu-calpain activation, increased protein tyrosine phosphatase (PTP) activity and decreased tyrosine phosphorylation. The degree to which calpain and individual PTPs were activated in response to A23187 depended on the extent of bivalent cation chelation in the external medium. EGTA (2 mM) blocked or severely retarded their activation, and addition of extracellular Ca2+ in excess (2 mM) resulted in virtually immediate tyrosine dephosphorylation. Dephosphorylation was correlated with an increase in total PTP activity in platelet lysates. In platelets stimulated by a combination of thrombin and collagen, only the subpopulation undergoing microvesicle release and isolated by their binding to annexin-V-coated magnetic beads exhibited protein tyrosine dephosphorylation. Detection of PTP activity in an 'in-gel' assay showed the Ca2+-dependent appearance of active low-molecular-mass bands at 38, 36 and 27 kDa. Individual PTPs varied in their protease sensitivity to changes in intracellular Ca2+ levels. For example, PTP1B was a more sensitive substrate than SH2-domain-containing tyrosine phosphatase-1 for mu-calpain cleavage. Incubation of platelets with the PTP inhibitors, phenylarsine oxide and benzylphosphonic acid acetoxymethyl ester, led to increased tyrosine phosphorylation and the surface expression of aminophospholipids but little microvesicle formation. Furthermore, microvesicle release in response to ionophore A23187 was inhibited. We conclude that platelet microvesicle formation is associated with extensive protein tyrosine dephosphorylation.
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Affiliation(s)
- J M Pasquet
- UMR 5533 CNRS, Hôpital Cardiologique, 33604 Pessac, France
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