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Lountos GT, Austin BP, Tropea JE, Waugh DS. Structure of human dual-specificity phosphatase 7, a potential cancer drug target. Acta Crystallogr F Struct Biol Commun 2015; 71:650-6. [PMID: 26057789 PMCID: PMC4461324 DOI: 10.1107/s2053230x1500504x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2015] [Accepted: 03/12/2015] [Indexed: 11/10/2022] Open
Abstract
Human dual-specificity phosphatase 7 (DUSP7/Pyst2) is a 320-residue protein that belongs to the mitogen-activated protein kinase phosphatase (MKP) subfamily of dual-specificity phosphatases. Although its precise biological function is still not fully understood, previous reports have demonstrated that DUSP7 is overexpressed in myeloid leukemia and other malignancies. Therefore, there is interest in developing DUSP7 inhibitors as potential therapeutic agents, especially for cancer. Here, the purification, crystallization and structure determination of the catalytic domain of DUSP7 (Ser141-Ser289/C232S) at 1.67 Å resolution are reported. The structure described here provides a starting point for structure-assisted inhibitor-design efforts and adds to the growing knowledge base of three-dimensional structures of the dual-specificity phosphatase family.
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Affiliation(s)
- George T. Lountos
- Basic Science Program, Leidos Biomedical Research Inc., Frederick National Laboratory for Cancer Research, Frederick, MD 21702, USA
- Macromolecular Crystallography Laboratory, Center for Cancer Research, National Cancer Institute at Frederick, PO Box B, Frederick, MD 21702, USA
| | - Brian P. Austin
- Macromolecular Crystallography Laboratory, Center for Cancer Research, National Cancer Institute at Frederick, PO Box B, Frederick, MD 21702, USA
| | - Joseph E. Tropea
- Macromolecular Crystallography Laboratory, Center for Cancer Research, National Cancer Institute at Frederick, PO Box B, Frederick, MD 21702, USA
| | - David S. Waugh
- Macromolecular Crystallography Laboratory, Center for Cancer Research, National Cancer Institute at Frederick, PO Box B, Frederick, MD 21702, USA
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Ríos P, Nunes-Xavier CE, Tabernero L, Köhn M, Pulido R. Dual-specificity phosphatases as molecular targets for inhibition in human disease. Antioxid Redox Signal 2014; 20:2251-73. [PMID: 24206177 DOI: 10.1089/ars.2013.5709] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
SIGNIFICANCE The dual-specificity phosphatases (DUSPs) constitute a heterogeneous group of cysteine-based protein tyrosine phosphatases, whose members exert a pivotal role in cell physiology by dephosphorylation of phosphoserine, phosphothreonine, and phosphotyrosine residues from proteins, as well as other non-proteinaceous substrates. RECENT ADVANCES A picture is emerging in which a selected group of DUSP enzymes display overexpression or hyperactivity that is associated with human disease, especially human cancer, making feasible targeted therapy approaches based on their inhibition. A panoply of molecular and functional studies on DUSPs have been performed in the previous years, and drug-discovery efforts are ongoing to develop specific and efficient DUSP enzyme inhibitors. This review summarizes the current status on inhibitory compounds targeting DUSPs that belong to the MAP kinase phosphatases-, small-sized atypical-, and phosphatases of regenerating liver subfamilies, whose inhibition could be beneficial for the prevention or mitigation of human disease. CRITICAL ISSUES Achieving specificity, potency, and bioavailability are the major challenges in the discovery of DUSP inhibitors for the clinics. Clinical validation of compounds or alternative inhibitory strategies of DUSP inhibition has yet to come. FUTURE DIRECTIONS Further work is required to understand the dual role of many DUSPs in human cancer, their function-structure properties, and to identify their physiologic substrates. This will help in the implementation of therapies based on DUSPs inhibition.
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Affiliation(s)
- Pablo Ríos
- 1 Genome Biology Unit, European Molecular Biology Laboratory , Heidelberg, Germany
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Román-García P, Carrillo-López N, Naves-Díaz M, Rodríguez I, Ortiz A, Cannata-Andía JB. Dual-specificity phosphatases are implicated in severe hyperplasia and lack of response to FGF23 of uremic parathyroid glands from rats. Endocrinology 2012; 153:1627-37. [PMID: 22334717 DOI: 10.1210/en.2011-1770] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Phosphate load accelerates the progression of secondary hyperparathyroidism (sHPT). In advanced stages of sHPT, there is a marked hyperplasia and resistance to classical regulatory endocrine factors such as calcium, calcitriol, or fibroblast growth factor 23 (FGF23), which suppresses PTH secretion by an ERK-dependent mechanism. Nephrectomized rats were fed with a high- or normal-phosphorus diet for different periods of time to induce sHPT. Biochemical parameters, parathyroid gland microarrays, quantitative real-time PCR, and immunohistochemistry (ERK/phospho-ERK) were performed. To test the role of dual-specificity phosphatases (Dusp) on parathyroid gland regulation, normal parathyroid glands were cultured with FGF23 and Dusp. Uremic rats fed with a high-phosphorus diet showed more severe sHPT, higher serum FGF23 levels and mortality, and decreased parathyroid Klotho gene expression. In all stages of sHPT, parathyroid microarrays displayed a widespread gene expression down-regulation; only a few genes were overexpressed, among them, Dusp5 and -6. In very severe sHPT, a significant reduction in phospho-ERK (the target of Dusp) and a significant increase of Dusp5 and -6 gene expression were observed. In ex vivo experiments with parathyroid glands, Dusp partially blocked the effect of FGF23 on PTH secretion, suggesting that Dusp might play a role in parathyroid regulation. The overexpression of Dusp and the inactivation of ERK found in the in vivo studies together with the ex vivo results might be indicative of the defense mechanism triggered to counteract hyperplasia, a mechanism that can also contribute to the resistance to the effect of FGF23 on parathyroid gland observed in advanced forms of chronic kidney disease.
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Affiliation(s)
- Pablo Román-García
- Servicio de Metabolismo Óseo y Mineral, Instituto Reina Sofía de Investigaciones Nefrológicas, Hospital Universitario Central de Asturias, 33006 Oviedo, Asturias, Spain
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Park HS, Jeon JY, Ryu SE, Kim SJ. Discovery of Novel Inhibitors of Dual-Specificity Phosphatase Pyst2 with Structure-Based Virtual Screening. B KOREAN CHEM SOC 2011. [DOI: 10.5012/bkcs.2011.32.7.2167] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Boutros T, Chevet E, Metrakos P. Mitogen-activated protein (MAP) kinase/MAP kinase phosphatase regulation: roles in cell growth, death, and cancer. Pharmacol Rev 2009; 60:261-310. [PMID: 18922965 DOI: 10.1124/pr.107.00106] [Citation(s) in RCA: 438] [Impact Index Per Article: 29.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Mitogen-activated protein kinase dual-specificity phosphatase-1 (also called MKP-1, DUSP1, ERP, CL100, HVH1, PTPN10, and 3CH134) is a member of the threonine-tyrosine dual-specificity phosphatases, one of more than 100 protein tyrosine phosphatases. It was first identified approximately 20 years ago, and since that time extensive investigations into both mkp-1 mRNA and protein regulation and function in different cells, tissues, and organs have been conducted. However, no general review on the topic of MKP-1 exists. As the subject matter pertaining to MKP-1 encompasses many branches of the biomedical field, we focus on the role of this protein in cancer development and progression, highlighting the potential role of the mitogen-activated protein kinase (MAPK) family. Section II of this article elucidates the MAPK family cross-talk. Section III reviews the structure of the mkp-1 encoding gene, and the known mechanisms regulating the expression and activity of the protein. Section IV is an overview of the MAPK-specific dual-specificity phosphatases and their role in cancer. In sections V and VI, mkp-1 mRNA and protein are examined in relation to cancer biology, therapeutics, and clinical studies, including a discussion of the potential role of the MAPK family. We conclude by proposing an integrated scheme for MKP-1 and MAPK in cancer.
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Affiliation(s)
- Tarek Boutros
- Department of Surgery, Royal Victoria Hospital, McGill University, 687 Pine Ave. W., Montreal, QC H3A1A1, Canada.
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Teng CH, Huang WN, Meng TC. Several dual specificity phosphatases coordinate to control the magnitude and duration of JNK activation in signaling response to oxidative stress. J Biol Chem 2007; 282:28395-28407. [PMID: 17681939 DOI: 10.1074/jbc.m705142200] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Mitogen-activated protein kinases (MAPKs) are important mediators that integrate signaling from upstream pathways in response to various environmental cues. In order to control appropriate gene expression through phosphorylation of transcription factors, the activity of MAPKs must be tightly regulated by the actions coordinated between protein kinases and phosphatases. In this study, we explore the underlying mechanism through which the oxidative stress-activated c-Jun N-terminal kinases (JNKs), members of MAPKs, are regulated by dual specificity phosphatases (DUSPs). DUSPs are a group of enzymes that belong to the superfamily of protein-tyrosine phosphatases. They are able to recognize phospho-Ser/Thr and phospho-Tyr residues in substrates. Using quantitative real time PCR, we found that stimulation of human embryonic kidney 293T cells with H(2)O(2) or xanthine/xanthine oxidase led to inducible expression of multiple DUSPs. We used RNA interference to characterize the functional role of these DUSPs and found rapid and transient induction of DUSP1 and DUSP10 to be essential for determining the appropriate magnitude of JNK activation in response to oxidative stress. The transcription factor ATF2, which is phosphorylated and activated by JNK, is a critical mediator for inducible expression of DUSP1 and DUSP10 in this signaling pathway. We further demonstrated that DUSP4 and DUSP16, both showing significant late phase induction, dephosphorylate JNK effectively, causing the down-regulation of the signaling cascade. Thus, this study provides new insights into the role of several DUSPs that coordinate with each other to control the magnitude and duration of JNK activity in response to oxidative stress.
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Affiliation(s)
- Chun-Hung Teng
- Institute of Biological Chemistry, Academia Sinica, 128 Academia Rd., Section 2, Taipei 11529, Taiwan
| | - Wen-Nin Huang
- Institute of Biological Chemistry, Academia Sinica, 128 Academia Rd., Section 2, Taipei 11529, Taiwan
| | - Tzu-Ching Meng
- Institute of Biological Chemistry, Academia Sinica, 128 Academia Rd., Section 2, Taipei 11529, Taiwan.
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Jeffrey KL, Camps M, Rommel C, Mackay CR. Targeting dual-specificity phosphatases: manipulating MAP kinase signalling and immune responses. Nat Rev Drug Discov 2007; 6:391-403. [PMID: 17473844 DOI: 10.1038/nrd2289] [Citation(s) in RCA: 376] [Impact Index Per Article: 22.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Dual-specificity phosphatases (DUSPs) are a subset of protein tyrosine phosphatases, many of which dephosphorylate threonine and tyrosine residues on mitogen-activated protein kinases (MAPKs), and hence are also referred to as MAPK phosphatases (MKPs). The regulated expression and activity of DUSP family members in different cells and tissues controls MAPK intensity and duration to determine the type of physiological response. For immune cells, DUSPs regulate responses in both positive and negative ways, and DUSP-deficient mice have been used to identify individual DUSPs as key regulators of immune responses. From a drug discovery perspective, DUSP family members are promising drug targets for manipulating MAPK-dependent immune responses in a cell-type and disease-context-dependent manner, to either boost or subdue immune responses in cancers, infectious diseases or inflammatory disorders.
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Affiliation(s)
- Kate L Jeffrey
- Immunology and Inflammation Research Program, The Garvan Institute, Darlinghurst, Sydney, NSW 2010, Australia
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Abstract
Mitogen-activated protein kinase (MAPK) phosphatases (MKPs) are protein phosphatases that dephosphorylate both the phosphothreonine and phosphotyrosine residues on activated MAPKs. Removal of the phosphates renders MAPKs inactive, effectively halting their cellular function. In recent years, evidence has emerged that, similar to MAPKs, MKPs are pivotal in the regulation of immune responses. By deactivating MAPKs, MKPs can modulate both innate and adaptive immunity. A number of immunomodulatory agents have been found to influence the expression of MKP1 in particular, highlighting the central role of this phosphatase in immune regulation. This Review discusses the properties, function and regulation of MKPs during immune responses.
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Affiliation(s)
- Yusen Liu
- Center for Perinatal Research, Columbus Children's Research Institute, Columbus Children's Hospital, Department of Pediatrics, The Ohio State University College of Medicine, Columbus, Ohio 43205, USA.
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Jesic S, Stojiljkovic L, Petrovic Z, Djordjevic V, Nesic V, Stosic S. Alteration of adenoid tissue alkaline and acid phosphatase in children with secretory otitis media. Int J Pediatr Otorhinolaryngol 2006; 70:1069-76. [PMID: 16406075 DOI: 10.1016/j.ijporl.2005.11.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/27/2005] [Revised: 11/01/2005] [Accepted: 11/17/2005] [Indexed: 11/20/2022]
Abstract
OBJECTIVE The role of pharyngeal lymphoid tissue in etiopathogenesis of secretory otitis is not yet defined. The influence of tonsillar and adenoid mass, weight, obstruction of naspharyngeal orrifitium, bacterial reservoire or some immunological events are of scientific interest. Tissue nonspecific alkaline phosphatase (TNAP) and acid phosphatase (ACP) are enzymes detected in lymphoid tissue, TNAP as characteristic of B cells, ACP as a characteristic of macrophages and folucullardentritic cells. These enzymes interfere in cell metabolism by removing 5' phosphate group from nucleotides and proteins. Specific activity and kinetic properties were studied in palatinal tonsils and adenoids of children with secretory otitis (OME) and compared with children with recurrent tonsillitis without ear involvement. METHOD Adenoid and tonsillar tissue of l7 children with OME and 30 children with recurrent tonsillitis were subjected to biochemical investigation using method of releasing of p-nitrophenol from p-nitrophenylphosphate (pNPP). Kinetic parameters as Michaelis-Menten constant were calculated by non-linear regression estimation method. RESULTS Specific activity of adenoid alkaline phosphatase was lower in children with OME in relation to children with recurrent tonsillitis (t=5.733507, p<0.01). Specific activity of adenoid acid phosphatase was also lower in children with OME (t=3.655456, p<0.01). pH optimum for both enzymes was the same in these two groups of children. Michaelis-Menten constant for both enzymes was significantly higher in adenoid of children with OME than in children with recurrent tonsillitis suggesting lower enzyme affinity for the substrate. CONCLUSION Differences in specific activities and kinetic properties of adenoid alkaline and acid phosphatases between children with OME and children with recurrent tonsillitis without OME were verified in this study. The results of the study are not able to explain the alteration of alkaline and acid phosphatase characteristics but could point to some possible and specific role of nasopharyngeal lymphoid tissue in pathogenesis of secretary otitis.
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Affiliation(s)
- Snezana Jesic
- Institute for Otorhinolaryngology and Maxillofacial surgery, Clinical Centre of Serbia, 11000 Belgrade, Pasterova 2 Street, Serbia and Montenegro.
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Wang SE, Wu FY, Shin I, Qu S, Arteaga CL. Transforming growth factor {beta} (TGF-{beta})-Smad target gene protein tyrosine phosphatase receptor type kappa is required for TGF-{beta} function. Mol Cell Biol 2005; 25:4703-15. [PMID: 15899872 PMCID: PMC1140650 DOI: 10.1128/mcb.25.11.4703-4715.2005] [Citation(s) in RCA: 69] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Transforming growth factor beta (TGF-beta) inhibits proliferation and promotes cell migration. In TGF-beta-treated MCF10A mammary epithelial cells overexpressing HER2 and by chromatin immunoprecipitation, we identified novel Smad targets including protein tyrosine phosphatase receptor type kappa (PTPRK). TGF-beta up-regulated PTPRK mRNA and RPTPkappa (receptor type protein tyrosine phosphatase kappa, the protein product encoded by the PTPRK gene) protein in tumor and nontumor mammary cells; HER2 overexpression down-regulated its expression. RNA interference (RNAi) of PTPRK accelerated cell cycle progression, enhanced response to epidermal growth factor (EGF), and abrogated TGF-beta-mediated antimitogenesis. Endogenous RPTPkappa associated with EGF receptor and HER2, resulting in suppression of basal and ErbB ligand-induced proliferation and receptor phosphorylation. In MCF10A/HER2 cells, TGF-beta enhanced cell motility, FAK phosphorylation, F-actin assembly, and focal adhesion formation and inhibited RhoA activity. These responses were abolished when RPTPkappa was eliminated by RNA interference (RNAi). In cells expressing RPTPkappa RNAi, phosphorylation of Src at Tyr527 was increased and (activating) phosphorylation of Src at Tyr416 was reduced. These data suggest that (i) RPTPkappa positively regulates Src; (ii) HER2 signaling and TGF-beta-induced RPTPkappa converge at Src, providing an adequate input for activation of FAK and increased cell motility and adhesion; and (iii) RPTPkappa is required for both the antiproliferative and the promigratory effects of TGF-beta.
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Affiliation(s)
- Shizhen Emily Wang
- Division of Oncology, Department of Cancer Biology, Vanderbilt University School of Medicine, 2220 Pierce Ave., 777 PRB, Nashville, TN 37232-6307, USA
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Berger IR, Buschbeck M, Bange J, Ullrich A. Identification of a transcriptionally active hVH-5 pseudogene on 10q22.2. ACTA ACUST UNITED AC 2005; 159:155-9. [PMID: 15899389 DOI: 10.1016/j.cancergencyto.2004.10.010] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2004] [Revised: 10/12/2004] [Accepted: 10/20/2004] [Indexed: 11/22/2022]
Abstract
Mitogen-activated protein kinases (MAPKs) are important regulators of a vast number of biological functions that affect life and death of eukaryotic cells and are tightly regulated by the concerted action of several phosphatases. Among these is the human homologue of vaccinia virus H1 phosphatase gene clone 5 (hVH-5) product, which dephosphorylates and thus inhibits members of the MAPK family. Here, we analyzed hVH-5 transcripts in mammary carcinoma cell lines and discovered a sequence with 88% similarity to hVH-5 transcripts. Because this variant of hVH-5 lacked intronic sequences in its genomic structure, we suggest it might be a processed pseudogene of hVH-5. psihVH-5 transcripts were detected in human peripheral tissues as well as in 11 of 14 breast cancer cell lines. In respect to the normal hVH-5 gene, the pseudogene contains several point mutations and a frame shift due to the deletion of 2 bases that would lead to the truncation of the putative psihVH-5 product.
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Affiliation(s)
- Ingemarie R Berger
- Department of Molecular Biology, Max-Planck-Institute of Biochemistry, Am Klopferspitz 18a, D-82152 Martinsried, Germany
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Farooq A, Zhou MM. Structure and regulation of MAPK phosphatases. Cell Signal 2004; 16:769-79. [PMID: 15115656 DOI: 10.1016/j.cellsig.2003.12.008] [Citation(s) in RCA: 346] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2003] [Accepted: 12/16/2003] [Indexed: 11/25/2022]
Abstract
MAP kinases (MAPKs), which control mitogenic signal transduction in all eukaryotic organisms, are inactivated by dual specificity MAPK phosphatases (DS-MKPs). Recent studies reveal that substrate specificity and enzymatic activity of MKPs are tightly controlled not only by the conserved C-terminal phosphatase domain but also by an N-terminal (NT) kinase-binding domain. Notably, MKPs that consist of a kinase-binding domain and a phosphatase domain exhibit little phosphatase activity in the absence of their physiological substrates. MKP binding to a specific MAPK results in enzymatic activation of the phosphatase in a substrate-induced activation mechanism. This direct coupling of inactivation of an MAPK to activation of an MKP provides a tightly controlled regulation that enables these two key enzymes to keep each other in check, thus guaranteeing the fidelity of signal transduction. This review discusses the recent understanding of structure and regulation of the large family of dual specificity MKPs, which can be divided into four subgroups according to their functional domains and mechanism of substrate recognition and enzymatic regulation. Moreover, detailed comparison of the structural basis between this unique substrate-induced activation mechanism and the common auto-inhibition mechanism is provided.
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Affiliation(s)
- Amjad Farooq
- Structural Biology Program, Department of Physiology and Biophysics, Mount Sinai School of Medicine, One Gustave L Levy Place, Box 1677, New York, NY 10029, USA.
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Granot-Attas S, Elson A. Protein tyrosine phosphatase epsilon activates Yes and Fyn in Neu-induced mammary tumor cells. Exp Cell Res 2004; 294:236-43. [PMID: 14980517 DOI: 10.1016/j.yexcr.2003.11.003] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2003] [Revised: 10/27/2003] [Indexed: 12/20/2022]
Abstract
The receptor-type form of protein tyrosine phosphatase epsilon (RPTP) is among the few tyrosine phosphatases that can support the transformed phenotype of tumor cells. Accordingly, cells from mammary epithelial tumors induced by activated Neu in mice genetically lacking RPTP appear morphologically less transformed and exhibit reduced proliferation. The effect of RPTP in these cells is mediated at least in part by its ability to activate Src, the prototypic member of a family of related kinases. We show here that RPTP is a physiological activator of two additional Src family kinases, Yes and Fyn. Activities of both kinases are inhibited in mammary tumor cells lacking RPTP, and phosphorylation at their C-terminal inhibitory tyrosines is increased. In agreement, opposite effects on activities and phosphorylation of Yes and Fyn are observed following increased expression of PTP. RPTP also forms stable complexes with either kinase, providing physical opportunity for their activation by RPTP. Surprisingly, expression of Yes or of Fyn does not rescue the morphological phenotype of RPTP-deficient tumor cells in contrast with the strong ability of Src to do so. We conclude that RPTP activates Src, Yes, and Fyn, but that these related kinases play distinct roles in Neu-induced mammary tumor cells.
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Affiliation(s)
- Shira Granot-Attas
- Department of Molecular Genetics, The Weizmann Institute of Science, Rehovot 76100, Israel
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Levy-Nissenbaum O, Sagi-Assif O, Kapon D, Hantisteanu S, Burg T, Raanani P, Avigdor A, Ben-Bassat I, Witz IP. Dual-specificity phosphatase Pyst2-L is constitutively highly expressed in myeloid leukemia and other malignant cells. Oncogene 2003; 22:7649-60. [PMID: 14576828 DOI: 10.1038/sj.onc.1206971] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Northern blotting confirmed previous results indicating that the mitogen-activated protein kinase (MAPK) phosphatase Pyst2-L was highly expressed in leukocytes obtained from acute myeloid leukemia (AML) patients. High levels of Pyst2-L mRNA were expressed in bone marrow (BM) and peripheral leukocytes from nine AML and acute lymphoblastic leukemia (ALL) patients. BM from healthy individuals expressed very low levels of Pyst2-L. Whereas high levels of Pyst2-L mRNA and protein were detected in several leukemia cell lines, Pyst2-L mRNA was detected neither in 33/34 samples of normal peripheral blood mononuclear cells (PBMC) nor in leukocyte fractions enriched with CD34+ cells. Certain solid tumor and lymphoblastoid cell lines expressed high levels of Pyst2-L mRNA. In view of the association of Pyst2-L to MAPK signaling cascades, we tested if cell activation, a process involving MAPK signaling, influences Pyst2-L expression. Indeed, activation of T cells and endothelial cells increased Pyst2-L in these cells. Furthermore, TPA, a known MAPK activator, induces the expression of both Pyst2-L mRNA as well as the Pyst2-L protein in leukemia cells. This induction was partially inhibited by PD098059, an Mek1/2-specific inhibitor. Based on the results of this and previous studies, we hypothesize that the high levels of Pyst2-L detected in the active state of AML and ALL diseases and in other types of cancer reflect an altered MAPK signaling pathway in such malignant processes. This alteration may be the result of a failed attempt to counter the constitutive activation of MAPK in transformed cells or alternatively, may represent the activated state of such cells.
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Affiliation(s)
- Orlev Levy-Nissenbaum
- Department of Cell Research and Immunology, George S Wise Faculty of Life Sciences, Tel-Aviv, Israel
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Gil-Henn H, Elson A. Tyrosine phosphatase-epsilon activates Src and supports the transformed phenotype of Neu-induced mammary tumor cells. J Biol Chem 2003; 278:15579-86. [PMID: 12598528 DOI: 10.1074/jbc.m210273200] [Citation(s) in RCA: 79] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
Few tyrosine phosphatases support, rather than inhibit, survival of tumor cells. We present genetic evidence that receptor-type protein-tyrosine phosphatase (RPTP)-epsilon performs such a function, as cells from mammary epithelial tumors induced by activated Neu in mice genetically lacking RPTPepsilon appeared morphologically less transformed and exhibited reduced proliferation. We show that at the molecular level, RPTPepsilon activates Src, a known collaborator of Neu in mammary tumorigenesis. Lack of RPTPepsilon reduced Src activity and altered Src phosphorylation in tumor cells; RPTPepsilon dephosphorylated and activated Src; and Src bound a substrate-trapping mutant of RPTPepsilon. The altered morphology of tumor cells lacking RPTPepsilon was corrected by exogenous Src and exogenous RPTPepsilon or RPTPalpha; exogenous activated Src corrected also the growth rate phenotype. Together, these results suggest that the altered morphology of RPTPepsilon-deficient tumor cells is caused by reduced Src activity, caused, in turn, by lack of RPTPepsilon. Unexpectedly, the phenotype of RPTPepsilon-deficient tumor cells occurs despite expression of the related RPTPalpha, indicating that endogenous RPTPalpha does not compensate for the absence of RPTPepsilon in this case. We conclude that RPTPepsilon is a physiological activator of Src in Neu-induced mammary tumors and suggest that pharmacological inhibition of phosphatases that activate Src may be useful to augment direct pharmacological inhibition of Src.
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Affiliation(s)
- Hava Gil-Henn
- Department of Molecular Genetics, The Weizmann Institute of Science, Herzl Street, Rehovot 76100, Israel
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Yang J, Yu Y, Duerksen-Hughes PJ. Protein kinases and their involvement in the cellular responses to genotoxic stress. Mutat Res 2003; 543:31-58. [PMID: 12510016 DOI: 10.1016/s1383-5742(02)00069-8] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Cells are constantly subjected to genotoxic stress, and much has been learned regarding their response to this type of stress during the past year. In general, the cellular genotoxic response can be thought to occur in three stages: (1) damage sensing; (2) activation of signal transduction pathways; (3) biological consequences and attenuation of the response. The biological consequences, in particular, include cell cycle arrest and cell death. Although our understanding of the molecular mechanisms underlying cellular genotoxic stress responses remains incomplete, many cellular components have been identified over the years, including a group of protein kinases that appears to play a major role. Various DNA-damaging agents can activate these protein kinases, triggering a protein phosphorylation cascade that leads to the activation of transcription factors, and altering gene expression. In this review, the involvement of protein kinases, particularly the mitogen-activated protein kinases (MAPKs), at different stages of the genotoxic response is discussed.
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Affiliation(s)
- Jun Yang
- Department of Pathophysiology, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310031, China
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Wachtel M, Frei K, Ehler E, Bauer C, Gassmann M, Gloor SM. Extracellular signal-regulated protein kinase activation during reoxygenation is required to restore ischaemia-induced endothelial barrier failure. Biochem J 2002; 367:873-9. [PMID: 12137564 PMCID: PMC1222922 DOI: 10.1042/bj20020746] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2002] [Revised: 07/22/2002] [Accepted: 07/23/2002] [Indexed: 01/28/2023]
Abstract
During an ischaemic insult, oedema formation occurs as a consequence of increased vascular permeability. To study mechanisms leading to vascular barrier failure, endothelial cells were exposed to ischaemia (1% O(2) in serum- and glucose-free medium) for 5 h. In in vitro conditions, ischaemia increased paracellular permeability, disassembled actin stress fibres, displaced focal adhesion kinase (FAK) from focal adhesions and enhanced cytoskeletal association of occludin. Reoxygenation restored paracellular barrier function, actin organization and FAK distribution. The mitogen-activated protein kinase (MAPK)/extracellular signal-regulated protein kinase (ERK) was rapidly activated after 30 min, strongly inhibited after 5 h of continuous ischaemia and reactivated 3 times more than control during reoxygenation. Inhibition of ERK activation during reoxygenation with U0126, an inhibitor of the ERK activator, MAPK/ERK kinase 1/2, prevented both barrier restoration and stress-fibre formation, but did not prevent recruitment of FAK to focal contacts. Under normoxic conditions, ERK inhibition led to barrier failure and disassembly of stress fibres only in the absence of serum. These results demonstrate that ERK activity is essential to rebuild a disrupted endothelial barrier after ischaemia and to maintain barrier function in cells exposed to non-ischaemic stress.
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Affiliation(s)
- Marco Wachtel
- Institute of Biochemistry, Swiss Federal Institute of Technology, ETH Zentrum, CH-8092 Zurich, Switzerland
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18
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Alonso A, Merlo JJ, Na S, Kholod N, Jaroszewski L, Kharitonenkov A, Williams S, Godzik A, Posada JD, Mustelin T. Inhibition of T cell antigen receptor signaling by VHR-related MKPX (VHX), a new dual specificity phosphatase related to VH1 related (VHR). J Biol Chem 2002; 277:5524-8. [PMID: 11733513 DOI: 10.1074/jbc.m107653200] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
A cDNA encoding a novel, human, dual-specific protein phosphatase was identified in the Incyte data base. The open reading frame predicted a protein of 184 amino acids related to the Vaccinia virus VH1 and human VH1-related (VHR) phosphatases. Expression VHR-related MKPX (VHX) was highest in thymus, but also detectable in monocytes and lymphocytes. A VHX-specific antiserum detected a protein with an apparent molecular mass of 19 kDa in many cells, including T lymphocytes and monocytes. VHX expression was not induced by T cell activation, but decreased somewhat at later time points. In vitro, VHX dephosphorylated the Erk2 mitogen-activated protein kinase with faster kinetics than did VHR, which is thought to be specific for Erk1 and 2. When expressed in Jurkat T cells, VHX had the capacity to suppress T cell antigen receptor-induced activation of Erk2 and of an NFAT/AP-1 luciferase reporter, but not an NF-kappaB reporter. Thus, VHX is a new member of the VH1/VHR group of small dual-specific phosphatases that act in mitogen-activated protein kinase signaling pathways.
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Affiliation(s)
- Andres Alonso
- Laboratory of Signal Transduction, La Jolla Cancer Research Center, The Burnham Institute, La Jolla, California 92037, USA
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19
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Abstract
Mitogen-activated protein MAP kinases are key signal-transducing enzymes that are activated by a wide range of extracellular stimuli. They are responsible for the induction of a number of cellular responses, such as changes in gene expression, proliferation, differentiation, cell cycle arrest and apoptosis. Although regulation of MAP kinases by a phosphorylation cascade has long been recognized as significant, their inactivation through the action of specific phosphatases has been less studied. An emerging family of structurally distinct dual-specificity serine, threonine and tyrosine phosphatases that act on MAP kinases consists of ten members in mammals, and members have been found in animals, plants and yeast. Three subgroups have been identified that differ in exon structure, sequence and substrate specificity.
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Affiliation(s)
- Aspasia Theodosiou
- The Breakthrough Breast Cancer Research Centre, Institute of Cancer Research, Fulham Road, London SW3 6JB, UK.
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20
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Ishibashi T, Shinogami M, Ishimoto S, Nibu K, Suzuki M, Kaga K. Identification of dual specificity phosphatases induced by olfactory bulbectomy in rat olfactory neuroepithelium. Brain Res 2001; 902:205-11. [PMID: 11384614 DOI: 10.1016/s0006-8993(01)02386-1] [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: 11/29/2022]
Abstract
Dual specificity protein tyrosine phosphatases (dsPTPs) are a subfamily of protein tyrosine phosphatases implicated in the regulation of extracellular signal-regulated kinase (ERK), c-Jun N-terminal kinase/stress-activated protein kinase (JNK/SAPK), and p38 mitogen-activated protein kinases (MAPKs) which are target enzymes activated by a wide range of cell-surface stimuli. Like these kinases, a class of dsPTP has been implicated in cell differentiation, regeneration, and apoptosis. In order to isolate dsPTPs which might play an important role in neuronal regeneration and apoptosis in olfactory neuroepithelium, we subcloned DNA fragments amplified by reverse transcription-polymerase chain reaction (RT-PCR), using degenerate oligonucleotide primers based on the conserved amino acid regions within the catalytic domain of dsPTPs, from rat olfactory epithelial RNA 1 and 4 h after an olfactory bulbectomy. The PCR products were subcloned into the pCRII vector, and 23 clones were chosen for further characterization. The sequence of these 23 individual clones revealed that two clones were identical to the rat dsPTP, MKP-3, and the other 21 clones were identical to the rat dsPTP, MKP-1. By Northern analysis, the MKP-1 transcript was induced and peaked 4 h following a bulbectomy. Similar results were obtained with the MKP-3 transcript. These results suggest that MKP-1 and MKP-3 may be involved in the early steps of apoptosis in vivo in rat olfactory neuroepithelium.
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Affiliation(s)
- T Ishibashi
- Department of Otolaryngology, Social Insurance Central General Hospital, 3-22-1, Hyakunincho, Shinnjuku-ku, 169-0073, Tokyo, Japan.
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21
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Slack DN, Seternes OM, Gabrielsen M, Keyse SM. Distinct binding determinants for ERK2/p38alpha and JNK map kinases mediate catalytic activation and substrate selectivity of map kinase phosphatase-1. J Biol Chem 2001; 276:16491-500. [PMID: 11278799 DOI: 10.1074/jbc.m010966200] [Citation(s) in RCA: 216] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Mitogen-activated protein (MAP) kinase phosphatase 1 (MKP-1/CL100) is an inducible nuclear dual specificity protein phosphatase that can dephosphorylate and inactivate both mitogen- and stress-activated protein kinases in vitro and in vivo. However, the molecular mechanism responsible for the substrate selectivity of MKP-1 is unknown. In addition, it has been suggested that the signal transducers and activators of transcription 1 (STAT1) transcription factor is a physiological non-MAP kinase substrate for MKP-1. We have used the yeast two-hybrid assay to demonstrate that MKP-1 is able to interact selectively with the extracellular signal-regulated kinase 1/2 (ERK1/2), p38alpha, and c-Jun NH(2)-terminal kinase (JNK) MAP kinase isoforms. Furthermore, this binding is accompanied by catalytic activation of recombinant MKP-1 protein in vitro, and these end points show an absolute correlation with MKP-1 substrate selectivity in vivo. In contrast, MKP-1 does not interact with STAT1. Recombinant STAT1 does not cause catalytic activation of MKP-1; nor does MKP-1 block tyrosine phosphorylation of STAT1 in vivo. Both binding and catalytic activation of MKP-1 are abrogated by mutation of a conserved docking site in ERK2, p38alpha, and JNK1 MAP kinases. Within MKP-1, MAP kinase binding is mediated by the amino-terminal noncatalytic domain of the protein. However, mutation of a conserved cluster of positively charged residues within this domain abolishes the binding and activation of MKP-1 by ERK2 and p38alpha but not JNK1, indicating that there are distinct binding determinants for these MAP kinase isoforms. We conclude that the substrate selectivity of MKP-1 is determined by specific protein-protein interactions coupled with catalytic activation of the phosphatase and that these interactions are restricted to members of the MAP kinase family of enzymes.
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Affiliation(s)
- D N Slack
- Imperial Cancer Research Fund Molecular Pharmacology Unit, Biomedical Research Centre, Level 5, Ninewells Hospital, Dundee DD1 9SY, Scotland, United Kingdom
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22
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Nichols A, Camps M, Gillieron C, Chabert C, Brunet A, Wilsbacher J, Cobb M, Pouyssegur J, Shaw JP, Arkinstall S. Substrate recognition domains within extracellular signal-regulated kinase mediate binding and catalytic activation of mitogen-activated protein kinase phosphatase-3. J Biol Chem 2000; 275:24613-21. [PMID: 10811804 DOI: 10.1074/jbc.m001515200] [Citation(s) in RCA: 81] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Mitogen-activated protein (MAP) kinase phosphatase-3 (MKP-3) is a dual specificity phosphatase that inactivates extracellular signal-regulated kinase (ERK) MAP kinases. This reflects tight and specific binding between ERK and the MKP-3 amino terminus with consequent phosphatase activation and dephosphorylation of the bound MAP kinase. We have used a series of p38/ERK chimeric molecules to identify domains within ERK necessary for binding and catalytic activation of MKP-3. These studies demonstrate that ERK kinase subdomains V-XI are necessary and sufficient for binding and catalytic activation of MKP-3. These domains constitute the major COOH-terminal structural lobe of ERK. p38/ERK chimeras possessing these regions display increased sensitivity to inactivation by MKP-3. These data also reveal an overlap between ERK domains interacting with MKP-3 and those known to confer substrate specificity on the ERK MAP kinase. Consistent with this, we show that peptides representing docking sites within the target substrates Elk-1 and p90(rsk) inhibit ERK-dependent activation of MKP-3. In addition, abolition of ERK-dependent phosphatase activation following mutation of a putative kinase interaction motif (KIM) within the MKP-3 NH(2) terminus suggests that key sites of contact for the ERK COOH-terminal structural lobe include residues localized between the Cdc25 homology domains (CH2) found conserved between members of the DSP gene family.
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Affiliation(s)
- A Nichols
- Serono Pharmaceutical Research Institute, Ares-Serono International SA, Plan-les-Ouates 1228, Geneva, Switzerland
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23
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CAMPS MONTSERRAT, NICHOLS ANTON, ARKINSTALL STEVE. Dual specificity phosphatases: a gene family for control of MAP kinase function. FASEB J 2000. [DOI: 10.1096/fasebj.14.1.6] [Citation(s) in RCA: 611] [Impact Index Per Article: 25.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- MONTSERRAT CAMPS
- Serono Pharmaceutical Research InstituteAres‐Serono International SA 1228 Plan‐les‐Ouates Geneva Switzerland
| | - ANTON NICHOLS
- Serono Pharmaceutical Research InstituteAres‐Serono International SA 1228 Plan‐les‐Ouates Geneva Switzerland
| | - STEVE ARKINSTALL
- Serono Pharmaceutical Research InstituteAres‐Serono International SA 1228 Plan‐les‐Ouates Geneva Switzerland
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24
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Elson A. Protein tyrosine phosphatase epsilon increases the risk of mammary hyperplasia and mammary tumors in transgenic mice. Oncogene 1999; 18:7535-42. [PMID: 10602512 DOI: 10.1038/sj.onc.1203098] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Accurate phosphorylation of tyrosine residues in proteins plays a central role in regulation of cellular function. Although connections between aberrant tyrosine kinase activity and malignancy are well-established, significantly less is known about the roles of protein tyrosine phosphatases (PTPases) in tumorigenesis. We have previously shown that the transmembranal form of PTPase Epsilon (PTPepsilon) is upregulated in mouse mammary tumors initiated specifically by ras or neu, suggesting that PTPepsilon may play a role in transformation by these two oncogenes. In order to test this notion in vivo, we created transgenic mice that express elevated levels of PTPepsilon in their mammary epithelium by use of the MMTV promoter/enhancer. Following several cycles of pregnancy female MMTV-PTPepsilon mice uniformly developed pronounced and persistent mammary hyperplasia which was accompanied by residual milk production. Solitary mammary tumors were often detected secondary to mammary hyperplasia. The sporadic nature of the tumors, the long latency period prior to their development, and low levels of transgene expression in the tumors indicate that PTPepsilon provides a necessary, but insufficient, signal for oncogenesis. The results provide genetic evidence that PTPepsilon plays an accessory role in production of mammary tumors in a manner consistent with its upregulation in mammary tumors induced by ras or neu.
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Affiliation(s)
- A Elson
- Department of Molecular Genetics, The Weizmann Institute of Science, Rehovot 76100, Israel
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25
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26
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27
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Abstract
The regulation of tyrosine phosphorylation represents a key mechanism governing cell proliferation. In fibroblasts, inputs from both growth factor and extracellular matrix receptors are required for cell division. Triggering such receptors induces a wave of tyrosine phosphorylation on key signaling molecules, culminating in the activation of cyclin-dependent kinases and cell cycle progression. In general, protein tyrosine kinases stimulate, while protein tyrosine phosphatases inhibit, such cell proliferation pathways. The role of protein tyrosine kinases in mitogenesis has been extensively studied, but the identity and targets of the protein tyrosine phosphatases that regulate cell growth are not well described. In this review, I will survey recent advances in the identification and regulation of protein tyrosine phosphatases that downregulate cell proliferation.
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Affiliation(s)
- J Chernoff
- Fox Chase Cancer Center, Philadelphia, Pennsylvania 19111, USA.
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28
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Haneda M, Sugimoto T, Kikkawa R. Mitogen-activated protein kinase phosphatase: a negative regulator of the mitogen-activated protein kinase cascade. Eur J Pharmacol 1999; 365:1-7. [PMID: 9988117 DOI: 10.1016/s0014-2999(98)00857-7] [Citation(s) in RCA: 91] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Mitogen-activated protein kinases (MAPKs) are activated by various stimuli, such as growth factors, cytokines, or stress, and are considered to be important mediators in intracellular signal transduction networks. The dual-specificity kinases, MAPK kinases (MKKs), which phosphorylate the TXY motif in the catalytic domain of MAPKs, can cause the activation of MAPKs. Recently, a family of dual-specificity phosphatases has been identified, members of which are able to dephosphorylate and inactivate MAPKs. The studies cited in this review have revealed that these MAPK phosphatases might play an important role in various cellular functions by downregulating the MAPK cascade.
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Affiliation(s)
- M Haneda
- The Third Department of Medicine, Shiga University of Medical Science, Seta Otsu, Japan.
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29
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Dowd S, Sneddon AA, Keyse SM. Isolation of the human genes encoding the pyst1 and Pyst2 phosphatases: characterisation of Pyst2 as a cytosolic dual-specificity MAP kinase phosphatase and its catalytic activation by both MAP and SAP kinases. J Cell Sci 1998; 111 ( Pt 22):3389-99. [PMID: 9788880 DOI: 10.1242/jcs.111.22.3389] [Citation(s) in RCA: 96] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
We have isolated the human genes encoding the Pyst1 (MKP-3) and Pyst2 (MKP-X) MAP kinase phosphatases. Both genes consist of three exons interrupted by two introns and lack an intron which is conserved in all the other members of this gene family characterised to date. This reinforces the conclusion that Pyst1 and Pyst2 are members of a distinct and structurally homologous subfamily of dual-specificity (Thr/Tyr) MAP kinase phosphatases. We find that Pyst2 mRNA is constitutively expressed in a wide variety of human cell lines including those derived from ovarian, bladder and breast cancers. While there is no evidence for inducible expression of Pyst2 mRNA in human skin fibroblasts in response to cellular stress, Pyst2 mRNA levels are moderately increased in response to serum stimulation. Pyst2 protein is predominantly cytosolic when expressed in COS-1 cells. In common with Pyst1, Pyst2 shows substrate selectivity for the classical p42 (ERK2) isoform of MAP kinase both in vitro and in vivo, displaying much reduced activity towards stress activated MAP kinase isoforms such as JNK-1 and p38/RK. Pyst2 binds p42 MAP kinase in vivo and both MAP kinase binding and substrate selectivity correlate with the ability of different recombinant MAP and SAP kinases to cause catalytic activation of the Pyst2 phosphatase in vitro.
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Affiliation(s)
- S Dowd
- ICRF Molecular Pharmacology Unit, Biomedical Research Centre, Ninewells Hospital, Dundee DD1 9SY, Scotland, UK
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