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Aziz F, Reddy K, Fernandez Vega V, Dey R, Hicks KA, Rao S, Jordan LO, Smith E, Shumate J, Scampavia L, Carpino N, Spicer TP, French JB. Rebamipide and Derivatives are Potent, Selective Inhibitors of Histidine Phosphatase Activity of the Suppressor of T Cell Receptor Signaling Proteins. J Med Chem 2024; 67:1949-1960. [PMID: 38252624 DOI: 10.1021/acs.jmedchem.3c01763] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2024]
Abstract
The suppressor of T cell receptor signaling (Sts) proteins are negative regulators of immune signaling. Genetic inactivation of these proteins leads to significant resistance to infection. From a 590,000 compound high-throughput screen, we identified the 2-(1H)-quinolinone derivative, rebamipide, as a putative inhibitor of Sts phosphatase activity. Rebamipide, and a small library of derivatives, are competitive, selective inhibitors of Sts-1 with IC50 values from low to submicromolar. SAR analysis indicates that the quinolinone, the acid, and the amide moieties are all essential for activity. A crystal structure confirmed the SAR and reveals key interactions between this class of compound and the protein. Although rebamipide has poor cell permeability, we demonstrated that a liposomal preparation can inactivate the phosphatase activity of Sts-1 in cells. These studies demonstrate that Sts-1 enzyme activity can be pharmacologically inactivated and provide foundational tools and insights for the development of immune-enhancing therapies that target the Sts proteins.
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Affiliation(s)
- Faisal Aziz
- The Hormel Institute, University of Minnesota, Austin, Minnesota 55912, United States
| | - Kanamata Reddy
- The Hormel Institute, University of Minnesota, Austin, Minnesota 55912, United States
| | - Virneliz Fernandez Vega
- Department of Molecular Medicine, The Herbert Wertheim UF Scripps Institute, Jupiter, Florida 33458, United States
| | - Raja Dey
- The Hormel Institute, University of Minnesota, Austin, Minnesota 55912, United States
| | - Katherine A Hicks
- Department of Chemistry, State University of New York at Cortland, Cortland, New York 13045, United States
| | - Sumitha Rao
- Department of Molecular Medicine, The Herbert Wertheim UF Scripps Institute, Jupiter, Florida 33458, United States
| | - Luis Ortiz Jordan
- Department of Molecular Medicine, The Herbert Wertheim UF Scripps Institute, Jupiter, Florida 33458, United States
| | - Emery Smith
- Department of Molecular Medicine, The Herbert Wertheim UF Scripps Institute, Jupiter, Florida 33458, United States
| | - Justin Shumate
- Department of Molecular Medicine, The Herbert Wertheim UF Scripps Institute, Jupiter, Florida 33458, United States
| | - Louis Scampavia
- Department of Molecular Medicine, The Herbert Wertheim UF Scripps Institute, Jupiter, Florida 33458, United States
| | - Nicholas Carpino
- Department of Microbiology and Immunology, Stony Brook University, Stony Brook, New York 11790, United States
| | - Timothy P Spicer
- Department of Molecular Medicine, The Herbert Wertheim UF Scripps Institute, Jupiter, Florida 33458, United States
| | - Jarrod B French
- The Hormel Institute, University of Minnesota, Austin, Minnesota 55912, United States
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Monticone G, Huang Z, Csibi F, Leit S, Ciccone D, Champhekar AS, Austin JE, Ucar DA, Hossain F, Ibba SV, Boulares AH, Carpino N, Xu K, Majumder S, Osborne BA, Loh C, Miele L. Targeting the Cbl-b-Notch1 axis as a novel immunotherapeutic strategy to boost CD8+ T-cell responses. Front Immunol 2022; 13:987298. [PMID: 36090975 PMCID: PMC9459147 DOI: 10.3389/fimmu.2022.987298] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2022] [Accepted: 08/08/2022] [Indexed: 12/03/2022] Open
Abstract
A critical feature of cancer is the ability to induce immunosuppression and evade immune responses. Tumor-induced immunosuppression diminishes the effectiveness of endogenous immune responses and decreases the efficacy of cancer immunotherapy. In this study, we describe a new immunosuppressive pathway in which adenosine promotes Casitas B-lineage lymphoma b (Cbl-b)-mediated Notch1 degradation, causing suppression of CD8+ T-cells effector functions. Genetic knockout and pharmacological inhibition of Cbl-b prevents Notch1 degradation in response to adenosine and reactivates its signaling. Reactivation of Notch1 results in enhanced CD8+ T-cell effector functions, anti-cancer response and resistance to immunosuppression. Our work provides evidence that targeting the Cbl-b-Notch1 axis is a novel promising strategy for cancer immunotherapy.
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Affiliation(s)
- Giulia Monticone
- Department of Genetics, Louisiana State University Health Sciences Center, New Orleans, LA, United States
| | - Zhi Huang
- Department of Genetics, Louisiana State University Health Sciences Center, New Orleans, LA, United States
| | - Fred Csibi
- Nimbus Therapeutics, Cambridge, MA, United States
| | - Silvana Leit
- Nimbus Therapeutics, Cambridge, MA, United States
| | | | - Ameya S. Champhekar
- Department of Microbiology, Immunology and Molecular Genetics, University of California, Los Angeles, CA, United States
| | - Jermaine E. Austin
- Department of Biology, University of Virginia, Charlottesville, VA, United States
| | - Deniz A. Ucar
- Department of Genetics, Louisiana State University Health Sciences Center, New Orleans, LA, United States
| | - Fokhrul Hossain
- Department of Genetics, Louisiana State University Health Sciences Center, New Orleans, LA, United States
| | - Salome V. Ibba
- Department of Interdisciplinary Oncology, Louisiana State University Health Sciences Center, New Orleans, LA, United States
| | - A. Hamid Boulares
- Department of Interdisciplinary Oncology, Louisiana State University Health Sciences Center, New Orleans, LA, United States
| | - Nicholas Carpino
- Department of Microbiology and Immunology, Stony Brook University, Stony Brook, NY, United States
| | - Keli Xu
- Department of Neurobiology and Anatomical Sciences, University of Mississippi Medical Center, Jackson, MS, United States
| | - Samarpan Majumder
- Department of Genetics, Louisiana State University Health Sciences Center, New Orleans, LA, United States
| | - Barbara A. Osborne
- Department of Veterinary and Animal Sciences, University of Massachusetts, Amherst, MA, United States
| | | | - Lucio Miele
- Department of Genetics, Louisiana State University Health Sciences Center, New Orleans, LA, United States
- *Correspondence: Lucio Miele,
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Parashar K, Carpino N. A role for the Sts phosphatases in negatively regulating IFNγ-mediated production of nitric oxide in monocytes. Immun Inflamm Dis 2020; 8:523-533. [PMID: 32841534 PMCID: PMC7654413 DOI: 10.1002/iid3.336] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/02/2020] [Revised: 07/01/2020] [Accepted: 07/20/2020] [Indexed: 12/17/2022]
Abstract
Introduction The atypical Sts phosphatases negatively regulate signaling pathways in diverse immune cell types, with two of their molecular targets being the related kinases Syk and Zap‐70. Mice lacking Sts expression (Sts−/−) are resistant to infection by the live vaccine strain (LVS) of Francisella tularensis. Although the mechanisms underlying the enhanced resistance of Sts−/− mice have not been definitively established, Sts−/− bone marrow‐derived monocytes (BMMs) demonstrate greater clearance of intracellular LVS following ex vivo infection, relative to wild type cells. To determine how the Sts proteins regulate monocyte bactericidal properties, we analyzed responses of infected cells. Methods Monocyte bacterial clearance was assayed using ex vivo coculture infections followed by colony‐forming unit analysis of intracellular bacteria. Levels of gene expression were quantified by quantitative reverse‐transcription polymerase chain reaction, levels of Nos2 protein levels were quantified by Western blot analysis, and levels of nitric oxide (NO) were quantified directly using the Griess reagent. We characterized monocyte cytokine production via enzyme‐linked immunosorbent assay. Results We demonstrate that Sts−/− monocyte cultures produce elevated levels of interferon‐γ (IFNγ) after infection, relative to wild type cultures. Sts−/− monocytes also demonstrate heightened responsiveness to IFNγ. Specifically, Sts−/− monocytes produce elevated levels of antimicrobial NO following IFNγ stimulation, and this NO plays an important role in LVS restriction. Additional IFNγ‐stimulated genes, including Ip10 and members of the Gbp gene family, also display heightened upregulation in Sts−/− cells. Both Sts‐1 and Sts‐2 contribute to the regulation of NO production, as evidenced by the responses of monocytes lacking each phosphatase individually. Finally, we demonstrate that the elevated production of IFNγ‐induced NO in Sts−/− monocytes is abrogated following chemical inhibition of Syk kinase. Conclusion Our results indicate a novel role for the Sts enzymes in regulating monocyte antibacterial responses downstream of IFNγ.
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Affiliation(s)
- Kaustubh Parashar
- Department of Microbiology and Immunology, Stony Brook University, Stony Brook, New York
| | - Nicholas Carpino
- Department of Microbiology and Immunology, Stony Brook University, Stony Brook, New York
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Zhou W, Yin Y, Smith E, Chou J, Shumate J, Scampavia L, Spicer TP, Carpino N, French JB. Discovery and Characterization of Two Classes of Selective Inhibitors of the Suppressor of the TCR Signaling Family of Proteins. ACS Infect Dis 2019; 5:250-259. [PMID: 30485744 DOI: 10.1021/acsinfecdis.8b00238] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The suppressor of T-cell receptor signaling (Sts) proteins, Sts-1, has recently emerged as a potential immunostimulatory target for drug development. Genetic inactivation of the Sts proteins dramatically increases host survival of systemic infection and leads to improved pathogen clearance. The protein tyrosine phosphatase (PTP) activity of these proteins arises from a C-terminal 2-histidine phosphatase (HP) domain. To identify new inhibitors of the HP activity of Sts-1, we miniaturized a phosphatase assay to a 1536-well format and conducted a 20 580 compound screen. Among the hits were two classes of structurally related compounds, tetracycline variants and sulfonated azo dyes. These hits had low micromolar to nanomolar IC50 values. Orthogonal screening confirmed the validity of these inhibitors and demonstrated that both act competitively on Sts-1 phosphatase activity. When tested on other PTPs, PTP1B and SHP1, it was found that the tetracycline PTP1B, SHP1, the tetracycline variant (doxycycline), and the sulfonated azo dye (Congo red) are selective inhibitors of Sts-1HP, with selectivity indices ranging from 19 to as high as 200. The planar polyaromatic moieties present in both classes of compounds suggested a common binding mode. The mutation of either tryptophan 494 or tyrosine 596, located near the active site of the protein, reduced the Ki of the inhibitors from 3- to 18-fold, indicating that these residues may help to promote the binding of substrates with aromatic groups. This work provides new insights into substrate selectivity mechanisms and describes two classes of compounds that can serve as probes of function or as a basis for future drug discovery.
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Affiliation(s)
| | | | - Emery Smith
- Department of Molecular Medicine, Scripps Research Molecular Screening Center, Scripps Research, 130 Scripps Way, Jupiter, Florida 33458, United States
| | | | - Justin Shumate
- Department of Molecular Medicine, Scripps Research Molecular Screening Center, Scripps Research, 130 Scripps Way, Jupiter, Florida 33458, United States
| | - Louis Scampavia
- Department of Molecular Medicine, Scripps Research Molecular Screening Center, Scripps Research, 130 Scripps Way, Jupiter, Florida 33458, United States
| | - Timothy P. Spicer
- Department of Molecular Medicine, Scripps Research Molecular Screening Center, Scripps Research, 130 Scripps Way, Jupiter, Florida 33458, United States
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Zhou W, Yin Y, Carpino N, French J. Phosphatase suppressor of T-cell receptor signaling pathway. Acta Crystallogr A Found Adv 2017. [DOI: 10.1107/s0108767317099317] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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6
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Rella A, Mor V, Farnoud AM, Singh A, Shamseddine AA, Ivanova E, Carpino N, Montagna MT, Luberto C, Del Poeta M. Role of Sterylglucosidase 1 (Sgl1) on the pathogenicity of Cryptococcus neoformans: potential applications for vaccine development. Front Microbiol 2015; 6:836. [PMID: 26322039 PMCID: PMC4531891 DOI: 10.3389/fmicb.2015.00836] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2015] [Accepted: 07/29/2015] [Indexed: 01/01/2023] Open
Abstract
Cryptococcosis caused by Cryptococcus neoformans and Cryptococcus gattii affects a large population and is a cause of significant morbidity and mortality. Despite its public health burden, there are currently no vaccines against cryptococcosis and new strategies against such infections are needed. In this study, we demonstrate that C. neoformans has the biochemical ability to metabolize sterylglucosides (SGs), a class of immunomodulatory glycolipids. Genetic manipulations that eliminate cryptococccal sterylglucosidase lead to the accumulation of SGs and generate a mutant strain (Δsgl1) that is non-pathogenic in the mouse models of cryptococcosis. Interestingly, this mutant strain acts as a vaccine strain and protects mice against cryptococcosis following infection with C. neoformans or C. gattii. The immunity induced by the Δsgl1 strain is not CD4+ T-cells dependent. Immunocompromised mice, which lack CD4+ T-cells, are able to control the infection by Δsgl1 and acquire immunity against the challenge by wild-type C. neoformans following vaccination with the Δsgl1 strain. These findings are particularly important in the context of HIV/AIDS immune deficiency and suggest that the Δsgl1 strain might provide a potential vaccination strategy against cryptococcosis.
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Affiliation(s)
- Antonella Rella
- Department of Molecular Genetics and Microbiology, Stony Brook University, Stony Brook NY, USA
| | - Visesato Mor
- Department of Molecular Genetics and Microbiology, Stony Brook University, Stony Brook NY, USA
| | - Amir M Farnoud
- Department of Molecular Genetics and Microbiology, Stony Brook University, Stony Brook NY, USA
| | - Ashutosh Singh
- Department of Molecular Genetics and Microbiology, Stony Brook University, Stony Brook NY, USA
| | | | - Elitza Ivanova
- Department of Molecular Genetics and Microbiology, Stony Brook University, Stony Brook NY, USA
| | - Nicholas Carpino
- Department of Molecular Genetics and Microbiology, Stony Brook University, Stony Brook NY, USA
| | - Maria T Montagna
- Department of Biomedical Science and Human Oncology, Hygiene Section, University of Bari Bari, Italy
| | - Chiara Luberto
- Department of Physiology and Biophysics, Stony Brook University, Stony Brook NY, USA
| | - Maurizio Del Poeta
- Department of Molecular Genetics and Microbiology, Stony Brook University, Stony Brook NY, USA
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7
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Cieniewicz B, Carpino N, Krug LT. Enhanced response of T cells from murine gammaherpesvirus 68-infected mice lacking the suppressor of T cell receptor signaling molecules Sts-1 and Sts-2. PLoS One 2014; 9:e90196. [PMID: 24587276 PMCID: PMC3938662 DOI: 10.1371/journal.pone.0090196] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2013] [Accepted: 01/27/2014] [Indexed: 12/17/2022] Open
Abstract
The human gammaherpesviruses establish life-long infections that are associated with the development of lymphomas and neoplasms, especially in immunocompromised individuals. T cells play a crucial role in the control of gammaherpesvirus infection through multiple functions, including the direct killing of infected cells, production of cytokines such as interferon-γ (IFN-γ), and costimulation of B cells. Impaired T cell function in mice infected with murine gammaherpesvirus 68 (MHV68) leads to increased reactivation and pathologies, including a higher incidence of lymphoid hyperplasia. Here we report that the absence of Suppressor of TCR signaling −1 and −2 (Sts-1-/-/2-/-) during MHV68 infection leads to the generation of T cells with significantly heightened responses. Transient differences in the T and B cell response of infected Sts-1-/-/2-/- (Sts dKO) mice were also observed when compared to WT mice. However, these alterations in the immune response and the overall absence of Sts-1 and Sts-2 did not impact viral pathogenesis or lead to pathology. Acute lytic replication in the lungs, establishment of latency in the spleen and reactivation from latency in the spleen in the Sts dKO mice were comparable to WT mice. Our studies indicate that Sts-1 and Sts-2 are not required for the immune control of MHV68 in a normal course of gammaherpesvirus infection, but suggest that interference with negative regulators of T cell responses might be further explored as a safe and efficacious strategy to improve adoptive T cell therapy.
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Affiliation(s)
- Brandon Cieniewicz
- Molecular and Cellular Biology Program and Department of Molecular Genetics and Microbiology, Stony Brook University, Stony Brook, New York, United States of America
| | - Nicholas Carpino
- Molecular and Cellular Biology Program and Department of Molecular Genetics and Microbiology, Stony Brook University, Stony Brook, New York, United States of America
| | - Laurie T. Krug
- Molecular and Cellular Biology Program and Department of Molecular Genetics and Microbiology, Stony Brook University, Stony Brook, New York, United States of America
- * E-mail:
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8
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Newman T, Carpino N, Ganea D, Safadi F, Tsygankov A. TULA-family proteins are key to the regulation of T-cell-driven inflammatory response. (50.1). The Journal of Immunology 2011. [DOI: 10.4049/jimmunol.186.supp.50.1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Abstract
The TULA-family consists of two proteins implicated in cellular regulation. TULA-1 is expressed in T-cells and is pro-apoptotic. TULA-2 is a ubiquitously expressed phosphatase that suppresses receptor-mediated signaling. T-cells from mice lacking TULA-1 and 2 (dKO) are hypersensitive to TCR stimulation. This may be due to these proteins having a similar function working synergistically or dissimilar functions having a convergent effect. To understand functional interaction of these proteins we have characterized TULA-family knockout mice without and during an immune challenge. We show that CD4+ T cells of dKO mice have an atypical CD45RB distribution, and that within this subset memory T-cells are expanded only in dKO not in single TULA knockouts. However, CD4+ T-cells of single knockout and wild-type mice respond differently to TCR stimulation as seen using signaling and responses in vitro. To evaluate consequences of TULA deficiency in vivo, we utilize two mouse models of inflammatory bowel disease: TNBS-induced colitis and colitis induced by the adoptive transfer of CD45RBHigh CD4+ T-cells. Studies utilizing TNBS indicate that deficiency of any TULA-family protein exacerbates TNBS-induced colitis. Likewise, dKO CD45RBHigh CD4+ T cells were significantly more colitogenic than cells from WT mice in the transfer model. Taken together, our data indicate that TULA-family proteins are key to the physiological regulation of T-cell reactivity that drives intestinal inflammation.
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Affiliation(s)
| | | | - Doina Ganea
- 1Temple University Sch. of Med., Philadelphia, PA
| | - Fayez Safadi
- 1Temple University Sch. of Med., Philadelphia, PA
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9
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Chen X, Ren L, Kim S, Carpino N, Daniel JL, Kunapuli SP, Tsygankov AY, Pei D. Determination of the substrate specificity of protein-tyrosine phosphatase TULA-2 and identification of Syk as a TULA-2 substrate. J Biol Chem 2010; 285:31268-76. [PMID: 20670933 PMCID: PMC2951201 DOI: 10.1074/jbc.m110.114181] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2010] [Revised: 07/28/2010] [Indexed: 11/06/2022] Open
Abstract
TULA-1 (UBASH3A/STS-2) and TULA-2 (p70/STS-1) represent a novel class of protein-tyrosine phosphatases. Previous studies suggest that TULA-2 is sequence-selective toward phosphotyrosyl (Tyr(P)) peptides. In this work the substrate specificity of TULA-1 and -2 was systematically evaluated by screening a combinatorial Tyr(P) peptide library. Although TULA-1 showed no detectable activity toward any of the Tyr(P) peptides in the library, TULA-2 recognizes two distinct classes of Tyr(P) substrates. On the N-terminal side of Tyr(P), the class I substrates contain a proline at the Tyr(P)-1 position, a hydrophilic residue at the Tyr(P)-2 position, and aromatic hydrophobic residues at positions Tyr(P)-3 and beyond. The class II substrates typically contain two or more acidic residues, especially at Tyr(P)-1 to Tyr(P)-3 positions, and aromatic hydrophobic residues at other positions. At the C-terminal side of Tyr(P), TULA-2 generally prefers acidic and aromatic residues. The library screening results were confirmed by kinetic analysis of representative peptides selected from the library as well as Tyr(P) peptides derived from various Tyr(P) proteins. TULA-2 is highly active toward peptides corresponding to the Tyr(P)-323 and Tyr(P)-352 sites of Syk, and the Tyr(P)-397 site of focal adhesion kinase and has lower activity toward other Tyr(P) sites in these proteins. In glycoprotein VI-stimulated platelets, knock-out of the TULA-2 gene significantly increased the phosphorylation level of Syk at Tyr-323 and Tyr-352 sites and to a lesser degree at the Tyr-525/526 sites. These results suggest that Syk is a bona fide TULA-2 substrate in platelets.
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Affiliation(s)
- Xianwen Chen
- From the Department of Chemistry and Ohio State Biochemistry Program, The Ohio State University, Columbus, Ohio 43210
| | - Lige Ren
- From the Department of Chemistry and Ohio State Biochemistry Program, The Ohio State University, Columbus, Ohio 43210
| | | | - Nicholas Carpino
- the Department of Molecular Genetics and Microbiology, Stony Brook University, Stony Brook, New York 11794, and
| | - James L. Daniel
- Pharmacology
- the Sol Sherry Thrombosis Research Center, Temple University School of Medicine, Philadelphia, Pennsylvania 19140
| | - Satya P. Kunapuli
- Physiology, and
- the Sol Sherry Thrombosis Research Center, Temple University School of Medicine, Philadelphia, Pennsylvania 19140
| | - Alexander Y. Tsygankov
- the Departments of Microbiology and Immunology
- the Fels Institute for Cancer Research and Molecular Biology, and
- the Sol Sherry Thrombosis Research Center, Temple University School of Medicine, Philadelphia, Pennsylvania 19140
| | - Dehua Pei
- From the Department of Chemistry and Ohio State Biochemistry Program, The Ohio State University, Columbus, Ohio 43210
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Pendeville H, Carpino N, Marine JC, Takahashi Y, Muller M, Martial JA, Cleveland JL. The ornithine decarboxylase gene is essential for cell survival during early murine development. Mol Cell Biol 2001; 21:6549-58. [PMID: 11533243 PMCID: PMC99801 DOI: 10.1128/mcb.21.19.6549-6558.2001] [Citation(s) in RCA: 186] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Overexpression and inhibitor studies have suggested that the c-Myc target gene for ornithine decarboxylase (ODC), the enzyme which converts ornithine to putrescine, plays an important role in diverse biological processes, including cell growth, differentiation, transformation, and apoptosis. To explore the physiological function of ODC in mammalian development, we generated mice harboring a disrupted ODC gene. ODC-heterozygous mice were viable, normal, and fertile. Although zygotic ODC is expressed throughout the embryo prior to implantation, loss of ODC did not block normal development to the blastocyst stage. Embryonic day E3.5 ODC-deficient embryos were capable of uterine implantation and induced maternal decidualization yet failed to develop substantially thereafter. Surprisingly, analysis of ODC-deficient blastocysts suggests that loss of ODC does not affect cell growth per se but rather is required for survival of the pluripotent cells of the inner cell mass. Therefore, ODC plays an essential role in murine development, and proper homeostasis of polyamine pools appears to be required for cell survival prior to gastrulation.
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Affiliation(s)
- H Pendeville
- Department of Biochemistry, St. Jude Children's Research Hospital, Memphis, Tennessee 38105, USA
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Abstract
The t(9;22) chromosomal translocation is found in almost all patients with chronic myelogenous leukemia. The resultant Bcr-Abl fusion gene expresses a chimeric fusion protein p210(bcr-abl) with increased tyrosine kinase activity. Hematopoietic progenitors isolated from chronic myelogenous leukemia patients in the chronic phase contain constitutively tyrosine-phosphorylated p62(dok) protein. p62(dok) associates with the Ras GTPase-activating protein (RasGAP), but only when p62(dok) is tyrosine phosphorylated. Here we have investigated the interaction between p62(dok) and RasGAP and the consequences of p62(dok) tyrosine phosphorylation on the activity of RasGAP. We have found that p62(dok) is directly tyrosine phosphorylated by p210(bcr-abl), and the sites of phosphorylation are located in the C-terminal half of the p62(dok) molecule. We have identified five tyrosine residues that are involved in in vitro RasGAP binding and have found that tyrosine-phosphorylated p62(dok) inhibits RasGAP activity. Our results suggest that p210(bcr-abl) might lead to the activation of the Ras signaling pathway by inhibiting a key down-regulator of Ras signaling.
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Affiliation(s)
- N Kashige
- Cold Spring Harbor Laboratory, 1 Bungtown Road, Cold Spring Harbor, NY 11724, USA
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Wang D, Moriggl R, Stravopodis D, Carpino N, Marine JC, Teglund S, Feng J, Ihle JN. A small amphipathic alpha-helical region is required for transcriptional activities and proteasome-dependent turnover of the tyrosine-phosphorylated Stat5. EMBO J 2000; 19:392-9. [PMID: 10654938 PMCID: PMC305576 DOI: 10.1093/emboj/19.3.392] [Citation(s) in RCA: 102] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
Cytokines induce the tyrosine phosphorylation and associated activation of signal transducers and activators of transcription (Stat). The mechanisms by which this response is terminated are largely unknown. Among a variety of inhibitors examined, the proteasome inhibitors MG132 and lactacystin affected Stat4, Stat5 and Stat6 turnover by significantly stabilizing the tyrosine-phosphorylated form. However, these proteasome inhibitors did not affect downregulation of the tyrosine-phosphorylated Stat1, Stat2 and Stat3. With Stat5 isoforms, we have observed that tyrosine-phosphorylated carboxyl-truncated forms of Stat5 proteins were considerably more stable than phosphorylated wild-type forms of the protein. Also, the C-terminal region of Stat5 could confer proteasome-dependent downregulation to Stat1. With a series of C-terminal deletion mutants, we have defined a relatively small, potentially amphipathic alpha-helical region that is required for the rapid turnover of the phosphorylated Stat5 proteins. The region is also required for transcriptional activation, suggesting that the functions are linked. The results are consistent with a model in which the transcriptional activation domain of activated Stat5 is required for its transcriptional activity and downregulation through a proteasome-dependent pathway.
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Affiliation(s)
- D Wang
- Department of Biochemistry, St Jude Children's Research Hospital, Memphis, TN 38105, USA
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Di Cristofano A, Carpino N, Dunant N, Friedland G, Kobayashi R, Strife A, Wisniewski D, Clarkson B, Pandolfi PP, Resh MD. Molecular cloning and characterization of p56dok-2 defines a new family of RasGAP-binding proteins. J Biol Chem 1998; 273:4827-30. [PMID: 9478921 DOI: 10.1074/jbc.273.9.4827] [Citation(s) in RCA: 117] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Chronic myelogenous leukemia (CML) is a disease characterized by the presence of p210(bcr-abl), a chimeric protein with tyrosine kinase activity. Substrates for p210(bcr-abl) are likely to be involved in the pathogenesis of CML. Here we describe the purification, cDNA cloning, and characterization of a 56-kDa tyrosine phosphorylated protein, p56(dok-2) (Dok-2), from p210(bcr-abl) expressing cells. The human dok-2 cDNA encodes a 412-amino acid protein with a predicted N-terminal pleckstrin homology domain as well as several other features of a signaling molecule, including 13 potential tyrosine phosphorylation sites, six PXXP motifs, and the ability to bind to p120(RasGAP). Dok-2 was shown to be 35% identical to p62(dok-1), a recently identified RasGAP binding protein from CML cells, and analysis of the expressed sequence tag data base revealed the presence of at least four additional proteins containing a Dok homology sequence motif. Dok mRNAs were primarily expressed in tissues of hematopoietic origin. These findings strongly suggest that a family of Dok-related proteins exists that bind to RasGAP and may mediate the effects of p210(bcr-abl) in CML.
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MESH Headings
- Adaptor Proteins, Signal Transducing
- Amino Acid Sequence
- Animals
- Carrier Proteins/genetics
- Carrier Proteins/metabolism
- Cell Line
- Cloning, Molecular
- DNA, Complementary/genetics
- DNA-Binding Proteins
- Fusion Proteins, bcr-abl/metabolism
- GTPase-Activating Proteins
- Hematopoietic Stem Cells/chemistry
- Humans
- Leukemia, Myelogenous, Chronic, BCR-ABL Positive/etiology
- Leukemia, Myelogenous, Chronic, BCR-ABL Positive/metabolism
- Mice
- Molecular Sequence Data
- Phosphoproteins/genetics
- Phosphoproteins/isolation & purification
- Phosphoproteins/metabolism
- Phosphorylation
- Protein Binding
- Protein-Tyrosine Kinases/metabolism
- Proteins/metabolism
- RNA-Binding Proteins
- Sequence Homology, Amino Acid
- Signal Transduction
- Tissue Distribution
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Affiliation(s)
- A Di Cristofano
- Department of Human Genetics and Molecular Biology Program, Memorial Sloan-Kettering Cancer Center, New York, New York 10021, USA
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Abstract
The 9;22 chromosomal translocation characteristic of CML results in a fused bcr/abl gene and an abnormal fusion protein, p210bcr/abl. Relative to normal c-abl, p210bc1/abl has elevated tyrosine kinase activity that is essential for its transforming activity. We recently reported a prominent 62 kDa GAP-associated P-tyr protein and five additional consistent but less prominent P-tyr proteins as well as five more minor P-tyr proteins that are constitutively tyrosine phosphorylated in primary primitive lineage negative (lin-) chronic phase CML blasts but not in comparable primary lin- normal blasts. The GAP-associated p62 protein has now been purified, sequenced and its gene has been cloned; it is a previously unidentified protein and is currently being characterized. In analyzing P-tyr proteins in primary lin- normal blasts in response to various hematopoietic cytokines, we found a striking similarity in the tyrosine phosphorylation of four major and three minor proteins after stimulation with c-kit ligand (KL) and the P-tyr proteins that are constitutively phosphorylated in primary primitive lin- chronic phase CML blasts. Other cytokines tested (ie GM-CSF, G-CSF, IL-3, FLT3 ligand, TPO, EPO) were much less active or stimulated phosphorylation of other proteins. KL/c-kit and bcr/abl have some similar activities including enhancing survival and expansion of hematopoietic progenitor cells, probably acting primarily on early progenitors at the time of lineage commitment rather than on self-renewing stem cells. Activation of growth factor receptors promote a cascade of protein phosphorylations that can ultimately result in a wide range of cellular responses. Sustained activation of discrete signaling pathways in some types of cells results in differentiation, whereas transient activation instead causes a proliferative response; in other cell types, the converse is true. It may be postulated that stem cells and primitive progenitors are at a particularly susceptible stage of development that renders them especially responsive to sustained bcr/abl-induced phorphorylation of a number of signaling proteins that are components of critical regulatory pathways, including c-kit. The affected pathways control and coordinate multiple diverse cell processes including proliferation, differentiation, maturation and apoptosis, processes that are normally tightly regulated and integrated. Perturbation of these key pathways in primitive progenitors would be expected to seriously disrupt orderly hematopoiesis and could also explain the multiple subtle pleiotropic biological abnormalities characteristically observed in later maturing CML compartments that we have collectively designated 'discordant maturation'. The true situation is undoubtedly very complex and involves interaction of multiple cytokines and signaling pathways that we are now trying to define. Constitutive downstream activation of critical pathways in susceptible early progenitors that normally require KL or other factors for activation could explain most if not all features of the disease.
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Affiliation(s)
- B D Clarkson
- Sloan-Kettering Institute for Cancer Research, Memorial Hospital for Cancer and Allied Diseases, Department of Medicine, Memorial Sloan-Kettering Cancer Center, New York, NY 10021, USA
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Carpino N, Wisniewski D, Strife A, Marshak D, Kobayashi R, Stillman B, Clarkson B. p62(dok): a constitutively tyrosine-phosphorylated, GAP-associated protein in chronic myelogenous leukemia progenitor cells. Cell 1997; 88:197-204. [PMID: 9008160 DOI: 10.1016/s0092-8674(00)81840-1] [Citation(s) in RCA: 304] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Characteristic of chronic myelogenous leukemia (CML) is the presence of the chimeric p210(bcr-abl) protein possessing elevated protein tyrosine kinase activity relative to normal c-abl tyrosine kinase. Hematopoietic progenitors isolated from CML patients in the chronic phase contain a constitutively tyrosine-phosphorylated protein that migrates at 62 kDa by SDS-PAGE and associates with the p120 ras GTPase-activating protein (GAP). We have purified p62(dok) from a hematopoietic cell line expressing p210(bcr-abl). p62(dok) is a novel protein with features of a signaling molecule. Association of p62(dok) with GAP correlates with its tyrosine phosphorylation. p62(dok) is rapidly tyrosine-phosphorylated upon activation of the c-Kit receptor, implicating it as a component of a signal transduction pathway downstream of receptor tyrosine kinases.
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Affiliation(s)
- N Carpino
- Cold Spring Harbor Laboratory, Cold Spring Harbor, New York 11724, USA
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