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Kästle M, Merten C, Hartig R, Kaehne T, Liaunardy-Jopeace A, Woessner NM, Schamel WW, James J, Minguet S, Simeoni L, Schraven B. Tyrosine 192 within the SH2 domain of the Src-protein tyrosine kinase p56 Lck regulates T-cell activation independently of Lck/CD45 interactions. Cell Commun Signal 2020; 18:183. [PMID: 33225946 PMCID: PMC7682018 DOI: 10.1186/s12964-020-00673-z] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2020] [Accepted: 10/13/2020] [Indexed: 01/09/2023] Open
Abstract
BACKGROUND Upon engagement of the T-cell receptor (TCR), the Src-family protein tyrosine kinase p56Lck phosphorylates components of the TCR (e.g. the TCRζ chains), thereby initiating T-cell activation. The enzymatic activity of Lck is primarily regulated via reversible and dynamic phosphorylation of two tyrosine residues, Y394 and Y505. Lck possesses an additional highly conserved tyrosine Y192, located within the SH2 domain, whose role in T-cell activation is not fully understood. METHODS Knock-in mice expressing a phospho-mimetic (Y192E) form of Lck were generated. Cellular and biochemical characterization was performed to elucidate the function of Y192 in primary T cells. HEK 293T and Jurkat T cells were used for in vitro studies. RESULTS Co-immunoprecipitation studies and biochemical analyses using T cells from LckY192E knock-in mice revealed a diminished binding of LckY192E to CD45 and a concomitant hyperphosphorylation of Y505, thus corroborating previous data obtained in Jurkat T cells. Surprisingly however, in vitro kinase assays showed that LckY192E possesses a normal enzymatic activity in human and murine T cells. FLIM/FRET measurements employing an LckY192E biosensor further indicated that the steady state conformation of the LckY192E mutant is similar to Lckwt. These data suggest that Y192 might regulate Lck functions also independently from the Lck/CD45-association. Indeed, when LckY192E was expressed in CD45-/-/Csk-/- non-T cells (HEK 293T cells), phosphorylation of Y505 was similar to Lckwt, but LckY192E still failed to optimally phosphorylate and activate the Lck downstream substrate ZAP70. Furthermore, LckY19E was recruited less to CD3 after TCR stimulation. CONCLUSIONS Taken together, phosphorylation of Y192 regulates Lck functions in T cells at least twofold, by preventing Lck association to CD45 and by modulating ligand-induced recruitment of Lck to the TCR. MAJOR FINDINGS Our data change the current view on the function of Y192 and suggest that Y192 also regulates Lck activity in a manner independent of Y505 phosphorylation. Video Abstract.
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Affiliation(s)
- Matthias Kästle
- Institute of Molecular and Clinical Immunology, Medical Faculty, Otto-von-Guericke University, Leipziger Str.44, Building 26, 39120, Magdeburg, Germany.,Health Campus Immunology, Infectiology and Inflammation (GC-I3), Medical Faculty, Otto-von-Guericke University, Magdeburg, Germany
| | - Camilla Merten
- Institute of Molecular and Clinical Immunology, Medical Faculty, Otto-von-Guericke University, Leipziger Str.44, Building 26, 39120, Magdeburg, Germany.,Health Campus Immunology, Infectiology and Inflammation (GC-I3), Medical Faculty, Otto-von-Guericke University, Magdeburg, Germany
| | - Roland Hartig
- Institute of Molecular and Clinical Immunology, Medical Faculty, Otto-von-Guericke University, Leipziger Str.44, Building 26, 39120, Magdeburg, Germany.,Health Campus Immunology, Infectiology and Inflammation (GC-I3), Medical Faculty, Otto-von-Guericke University, Magdeburg, Germany
| | - Thilo Kaehne
- Institute of Experimental Internal Medicine, Medical Faculty, Otto-von-Guericke University, Magdeburg, Germany
| | | | - Nadine M Woessner
- Spemann Graduate School of Biology and Medicine (SGBM), Albert-Ludwigs-University Freiburg, Freiburg, Germany.,Faculty of Biology, Signalling Research Centres BIOSS and CIBSS, University of Freiburg, Freiburg, Germany.,Center of Chronic Immunodeficiency CCI, University Clinics and Medical Faculty, Freiburg, Germany
| | - Wolfgang W Schamel
- Faculty of Biology, Signalling Research Centres BIOSS and CIBSS, University of Freiburg, Freiburg, Germany.,Center of Chronic Immunodeficiency CCI, University Clinics and Medical Faculty, Freiburg, Germany
| | - John James
- Molecular Immunity Unit, Department of Medicine, University of Cambridge, MRC-LMB, Cambridge, UK.,Division of Biomedical Sciences, Warwick Medical School, University of Warwick, Gibbet Hill, Coventry, UK
| | - Susana Minguet
- Faculty of Biology, Signalling Research Centres BIOSS and CIBSS, University of Freiburg, Freiburg, Germany.,Center of Chronic Immunodeficiency CCI, University Clinics and Medical Faculty, Freiburg, Germany
| | - Luca Simeoni
- Institute of Molecular and Clinical Immunology, Medical Faculty, Otto-von-Guericke University, Leipziger Str.44, Building 26, 39120, Magdeburg, Germany. .,Health Campus Immunology, Infectiology and Inflammation (GC-I3), Medical Faculty, Otto-von-Guericke University, Magdeburg, Germany.
| | - Burkhart Schraven
- Institute of Molecular and Clinical Immunology, Medical Faculty, Otto-von-Guericke University, Leipziger Str.44, Building 26, 39120, Magdeburg, Germany. .,Health Campus Immunology, Infectiology and Inflammation (GC-I3), Medical Faculty, Otto-von-Guericke University, Magdeburg, Germany.
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2
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Glatzová D, Cebecauer M. Dual Role of CD4 in Peripheral T Lymphocytes. Front Immunol 2019; 10:618. [PMID: 31001252 PMCID: PMC6454155 DOI: 10.3389/fimmu.2019.00618] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2018] [Accepted: 03/08/2019] [Indexed: 01/07/2023] Open
Abstract
The interaction of T-cell receptors (TCRs) with self- and non-self-peptides in the major histocompatibility complex (MHC) stimulates crucial signaling events, which in turn can activate T lymphocytes. A variety of accessory molecules further modulate T-cell signaling. Of these, the CD4 and CD8 coreceptors make the most critical contributions to T cell sensitivity in vivo. Whereas, CD4 function in T cell development is well-characterized, its role in peripheral T cells remains incompletely understood. It was originally suggested that CD4 stabilizes weak interactions between TCRs and peptides in the MHC and delivers Lck kinases to that complex. The results of numerous experiments support the latter role, indicating that the CD4-Lck complex accelerates TCR-triggered signaling and controls the availability of the kinase for TCR in the absence of the ligand. On the other hand, extremely low affinity of CD4 for MHC rules out its ability to stabilize the receptor-ligand complex. In this review, we summarize the current knowledge on CD4 in T cells, with a special emphasis on the spatio-temporal organization of early signaling events and the relevance for CD4 function. We further highlight the capacity of CD4 to interact with the MHC in the absence of TCR. It drives the adhesion of T cells to the cells that express the MHC. This process is facilitated by the CD4 accumulation in the tips of microvilli on the surface of unstimulated T cells. Based on these observations, we suggest an alternative model of CD4 role in T-cell activation.
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Affiliation(s)
- Daniela Glatzová
- Department of Biophysical Chemistry, J. Heyrovsky Institute of Physical Chemistry of the Czech Academy of Sciences, Prague, Czechia
- Laboratory of Leukocyte Signaling, Institute of Molecular Genetics of the Czech Academy of Sciences, Prague, Czechia
| | - Marek Cebecauer
- Department of Biophysical Chemistry, J. Heyrovsky Institute of Physical Chemistry of the Czech Academy of Sciences, Prague, Czechia
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3
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4
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Courtney AH, Amacher JF, Kadlecek TA, Mollenauer MN, Au-Yeung BB, Kuriyan J, Weiss A. A Phosphosite within the SH2 Domain of Lck Regulates Its Activation by CD45. Mol Cell 2017; 67:498-511.e6. [PMID: 28735895 DOI: 10.1016/j.molcel.2017.06.024] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2016] [Revised: 03/24/2017] [Accepted: 06/20/2017] [Indexed: 10/19/2022]
Abstract
The Src Family kinase Lck sets a critical threshold for T cell activation because it phosphorylates the TCR complex and the Zap70 kinase. How a T cell controls the abundance of active Lck molecules remains poorly understood. We have identified an unappreciated role for a phosphosite, Y192, within the Lck SH2 domain that profoundly affects the amount of active Lck in cells. Notably, mutation of Y192 blocks critical TCR-proximal signaling events and impairs thymocyte development in retrogenic mice. We determined that these defects are caused by hyperphosphorylation of the inhibitory C-terminal tail of Lck. Our findings reveal that modification of Y192 inhibits the ability of CD45 to associate with Lck in cells and dephosphorylate the C-terminal tail of Lck, which prevents its adoption of an active open conformation. These results suggest a negative feedback loop that responds to signaling events that tune active Lck amounts and TCR sensitivity.
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Affiliation(s)
- Adam H Courtney
- Division of Rheumatology, Rosalind Russell and Ephraim P. Engleman Arthritis Research Center, Department of Medicine, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Jeanine F Amacher
- Departments of Molecular and Cell Biology and Chemistry, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Theresa A Kadlecek
- The Howard Hughes Medical Institute, University of California, San Francisco, San Francisco, CA 04143, USA
| | - Marianne N Mollenauer
- The Howard Hughes Medical Institute, University of California, San Francisco, San Francisco, CA 04143, USA
| | - Byron B Au-Yeung
- Division of Rheumatology, Rosalind Russell and Ephraim P. Engleman Arthritis Research Center, Department of Medicine, University of California, San Francisco, San Francisco, CA 94143, USA
| | - John Kuriyan
- Departments of Molecular and Cell Biology and Chemistry, University of California, Berkeley, Berkeley, CA 94720, USA; The Howard Hughes Medical Institute, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Arthur Weiss
- Division of Rheumatology, Rosalind Russell and Ephraim P. Engleman Arthritis Research Center, Department of Medicine, University of California, San Francisco, San Francisco, CA 94143, USA; The Howard Hughes Medical Institute, University of California, San Francisco, San Francisco, CA 04143, USA.
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5
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Blas-Rus N, Bustos-Morán E, Martín-Cófreces NB, Sánchez-Madrid F. Aurora-A shines on T cell activation through the regulation of Lck. Bioessays 2016; 39. [PMID: 27910998 DOI: 10.1002/bies.201600156] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Different protein kinases control signaling emanating from the T cell receptor (TCR) during antigen-specific T cell activation. Mitotic kinases, e.g. Aurora-A, have been widely studied in the context of mitosis due to their role during microtubule (MT) nucleation, becoming critical regulators of cell cycle progression. We have recently described a specific role for Aurora-A kinase in antigenic T cell activation. Blockade of Aurora-A in T cells severely disrupts the dynamics of MTs and CD3ζ-bearing signaling vesicles during T cell activation. Furthermore, Aurora-A deletion impairs the activation of signaling molecules downstream of the TCR. Targeting Aurora-A disturbs the activation of Lck, which is one of the first signals that drive T cell activation in an antigen-dependent manner. This work describes possible models of regulation of Lck by Aurora-A during T cell activation. We also discuss possible roles for Aurora-A in other systems similar to the IS, and its putative functions in cell polarization.
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Affiliation(s)
- Noelia Blas-Rus
- Servicio de Inmunología, Hospital Universitario de la Princesa, Instituto Investigación Sanitaria Princesa (IIS-IP), Universidad Autónoma de Madrid, Madrid, Spain
| | - Eugenio Bustos-Morán
- Vascular Pathophysiology Area, Centro Nacional Investigaciones Cardiovasculares (CNIC), Madrid, Spain
| | - Noa B Martín-Cófreces
- Vascular Pathophysiology Area, Centro Nacional Investigaciones Cardiovasculares (CNIC), Madrid, Spain
| | - Francisco Sánchez-Madrid
- Servicio de Inmunología, Hospital Universitario de la Princesa, Instituto Investigación Sanitaria Princesa (IIS-IP), Universidad Autónoma de Madrid, Madrid, Spain.,Vascular Pathophysiology Area, Centro Nacional Investigaciones Cardiovasculares (CNIC), Madrid, Spain
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6
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Kapoor-Kaushik N, Hinde E, Compeer EB, Yamamoto Y, Kraus F, Yang Z, Lou J, Pageon SV, Tabarin T, Gaus K, Rossy J. Distinct Mechanisms Regulate Lck Spatial Organization in Activated T Cells. Front Immunol 2016; 7:83. [PMID: 27014263 PMCID: PMC4782156 DOI: 10.3389/fimmu.2016.00083] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2015] [Accepted: 02/22/2016] [Indexed: 11/15/2022] Open
Abstract
Phosphorylation of the T cell receptor (TCR) by the kinase Lck is the first detectable signaling event upon antigen engagement. The distribution of Lck within the plasma membrane, its conformational state, kinase activity, and protein–protein interactions all contribute to determine how efficiently Lck phosphorylates the engaged TCR. Here, we used cross-correlation raster image correlation spectroscopy and photoactivated localization microscopy to identify two mechanisms of Lck clustering: an intrinsic mechanism of Lck clustering induced by locking Lck in its open conformation and an extrinsic mechanism of clustering controlled by the phosphorylation of tyrosine 192, which regulates the affinity of Lck SH2 domain. Both mechanisms of clustering were differently affected by the absence of the kinase Zap70 or the adaptor Lat. We further observed that the adaptor TSAd bound to and promoted the diffusion of Lck when it is phosphorylated on tyrosine 192. Our data suggest that while Lck open conformation drives aggregation and clustering, the spatial organization of Lck is further controlled by signaling events downstream of TCR phosphorylation.
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Affiliation(s)
- Natasha Kapoor-Kaushik
- EMBL Australia Node in Single Molecule Science, School of Medical Science, University of New South Wales , Sydney, NSW , Australia
| | - Elizabeth Hinde
- EMBL Australia Node in Single Molecule Science, School of Medical Science, University of New South Wales, Sydney, NSW, Australia; ARC Centre of Excellence in Advanced Molecular Imaging, University of New South Wales, Sydney, NSW, Australia
| | - Ewoud B Compeer
- EMBL Australia Node in Single Molecule Science, School of Medical Science, University of New South Wales , Sydney, NSW , Australia
| | - Yui Yamamoto
- EMBL Australia Node in Single Molecule Science, School of Medical Science, University of New South Wales, Sydney, NSW, Australia; ARC Centre of Excellence in Advanced Molecular Imaging, University of New South Wales, Sydney, NSW, Australia
| | - Felix Kraus
- EMBL Australia Node in Single Molecule Science, School of Medical Science, University of New South Wales , Sydney, NSW , Australia
| | - Zhengmin Yang
- EMBL Australia Node in Single Molecule Science, School of Medical Science, University of New South Wales, Sydney, NSW, Australia; ARC Centre of Excellence in Advanced Molecular Imaging, University of New South Wales, Sydney, NSW, Australia
| | - Jieqiong Lou
- EMBL Australia Node in Single Molecule Science, School of Medical Science, University of New South Wales , Sydney, NSW , Australia
| | - Sophie V Pageon
- EMBL Australia Node in Single Molecule Science, School of Medical Science, University of New South Wales, Sydney, NSW, Australia; ARC Centre of Excellence in Advanced Molecular Imaging, University of New South Wales, Sydney, NSW, Australia
| | - Thibault Tabarin
- EMBL Australia Node in Single Molecule Science, School of Medical Science, University of New South Wales, Sydney, NSW, Australia; ARC Centre of Excellence in Advanced Molecular Imaging, University of New South Wales, Sydney, NSW, Australia
| | - Katharina Gaus
- EMBL Australia Node in Single Molecule Science, School of Medical Science, University of New South Wales, Sydney, NSW, Australia; ARC Centre of Excellence in Advanced Molecular Imaging, University of New South Wales, Sydney, NSW, Australia
| | - Jérémie Rossy
- EMBL Australia Node in Single Molecule Science, School of Medical Science, University of New South Wales, Sydney, NSW, Australia; ARC Centre of Excellence in Advanced Molecular Imaging, University of New South Wales, Sydney, NSW, Australia
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7
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Goodfellow HS, Frushicheva MP, Ji Q, Cheng DA, Kadlecek TA, Cantor AJ, Kuriyan J, Chakraborty AK, Salomon A, Weiss A. The catalytic activity of the kinase ZAP-70 mediates basal signaling and negative feedback of the T cell receptor pathway. Sci Signal 2015; 8:ra49. [PMID: 25990959 DOI: 10.1126/scisignal.2005596] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
T cell activation by antigens binding to the T cell receptor (TCR) must be properly regulated to ensure normal T cell development and effective immune responses to pathogens and transformed cells while avoiding autoimmunity. The Src family kinase Lck and the Syk family kinase ZAP-70 (ζ chain-associated protein kinase of 70 kD) are sequentially activated in response to TCR engagement and serve as critical components of the TCR signaling machinery that leads to T cell activation. We performed a mass spectrometry-based phosphoproteomic study comparing the quantitative differences in the temporal dynamics of phosphorylation in stimulated and unstimulated T cells with or without inhibition of ZAP-70 catalytic activity. The data indicated that the kinase activity of ZAP-70 stimulates negative feedback pathways that target Lck and thereby modulate the phosphorylation patterns of the immunoreceptor tyrosine-based activation motifs (ITAMs) of the CD3 and ζ chain components of the TCR and of signaling molecules downstream of Lck, including ZAP-70. We developed a computational model that provides a mechanistic explanation for the experimental findings on ITAM phosphorylation in wild-type cells, ZAP-70-deficient cells, and cells with inhibited ZAP-70 catalytic activity. This model incorporated negative feedback regulation of Lck activity by the kinase activity of ZAP-70 and predicted the order in which tyrosines in the ITAMs of TCR ζ chains must be phosphorylated to be consistent with the experimental data.
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Affiliation(s)
- Hanna Sjölin Goodfellow
- Howard Hughes Medical Institute, UCSF, San Francisco, CA 94143, USA.,Department of Medicine, UCSF, San Francisco, CA 94143, USA
| | - Maria P Frushicheva
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, MA 02142, USA
| | - Qinqin Ji
- Department of Chemistry, Brown University, Providence, RI 02912, USA
| | - Debra A Cheng
- Howard Hughes Medical Institute, UCSF, San Francisco, CA 94143, USA.,Department of Medicine, UCSF, San Francisco, CA 94143, USA
| | - Theresa A Kadlecek
- Howard Hughes Medical Institute, UCSF, San Francisco, CA 94143, USA.,Department of Medicine, UCSF, San Francisco, CA 94143, USA
| | - Aaron J Cantor
- Department of Molecular and Cell Biology, University of California, Berkeley, CA 94720, USA.,California Institute for Quantitative Biosciences, University of California, Berkeley, CA 94720, USA
| | - John Kuriyan
- Department of Molecular and Cell Biology, University of California, Berkeley, CA 94720, USA.,California Institute for Quantitative Biosciences, University of California, Berkeley, CA 94720, USA.,Department of Chemistry, University of California, Berkeley, CA 94720, USA.,Howard Hughes Medical Institute, University of California, Berkeley, CA 94720, USA.,Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Arup K Chakraborty
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, MA 02142, USA.,Department of Physics, Massachusetts Institute of Technology, Cambridge, MA 02142, USA.,Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA 02142, USA.,Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA 02142, USA.,Institute for Medical Engineering & Science, Massachusetts Institute of Technology, Cambridge, MA 02142, USA.,Ragon Institute of MGH, MIT, and Harvard, Cambridge, MA 02139, USA
| | - Arthur Salomon
- Department of Chemistry, Brown University, Providence, RI 02912, USA.,Department of Molecular Biology, Cell Biology, and Biochemistry, Brown University, Providence, RI 02912, USA
| | - Arthur Weiss
- Howard Hughes Medical Institute, UCSF, San Francisco, CA 94143, USA.,Department of Medicine, UCSF, San Francisco, CA 94143, USA
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8
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Jin LL, Wybenga-Groot LE, Tong J, Taylor P, Minden MD, Trudel S, McGlade CJ, Moran MF. Tyrosine phosphorylation of the Lyn Src homology 2 (SH2) domain modulates its binding affinity and specificity. Mol Cell Proteomics 2015; 14:695-706. [PMID: 25587033 DOI: 10.1074/mcp.m114.044404] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Src homology 2 (SH2) domains are modular protein structures that bind phosphotyrosine (pY)-containing polypeptides and regulate cellular functions through protein-protein interactions. Proteomics analysis showed that the SH2 domains of Src family kinases are themselves tyrosine phosphorylated in blood system cancers, including acute myeloid leukemia, chronic lymphocytic leukemia, and multiple myeloma. Using the Src family kinase Lyn SH2 domain as a model, we found that phosphorylation at the conserved SH2 domain residue Y(194) impacts the affinity and specificity of SH2 domain binding to pY-containing peptides and proteins. Analysis of the Lyn SH2 domain crystal structure supports a model wherein phosphorylation of Y(194) on the EF loop modulates the binding pocket that engages amino acid side chains at the pY+2/+3 position. These data indicate another level of regulation wherein SH2-mediated protein-protein interactions are modulated by SH2 kinases and phosphatases.
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Affiliation(s)
- Lily L Jin
- From the ‡Molecular Structure and Function, The Hospital For Sick Children, 686 Bay Street, Toronto, M5G 0A4, Canada; ‡‡Departments of Molecular Genetics, Medical Science Building, Room 4386, 1 King's College Circle, Toronto, ON M5S 1A8, Canada
| | - Leanne E Wybenga-Groot
- §Cell Biology, The Hospital For Sick Children, 686 Bay Street, Toronto, M5G 0A4, Canada; ¶The Arthur and Sonia Labatt Brain Tumour Research Centre, The Hospital For Sick Children, 686 Bay Street, Toronto, M5G 0A4, Canada
| | - Jiefei Tong
- From the ‡Molecular Structure and Function, The Hospital For Sick Children, 686 Bay Street, Toronto, M5G 0A4, Canada
| | - Paul Taylor
- From the ‡Molecular Structure and Function, The Hospital For Sick Children, 686 Bay Street, Toronto, M5G 0A4, Canada
| | - Mark D Minden
- ‖Medical Biophysics, University of Toronto, Medical Science Building, Room 4386, 1 King's College Circle, Toronto, ON M5S 1A8, Canada; **The Princess Margaret Cancer Center, 610 University Avenue, M5G 2M9, Toronto, Canada
| | - Suzanne Trudel
- ‖Medical Biophysics, University of Toronto, Medical Science Building, Room 4386, 1 King's College Circle, Toronto, ON M5S 1A8, Canada; **The Princess Margaret Cancer Center, 610 University Avenue, M5G 2M9, Toronto, Canada
| | - C Jane McGlade
- §Cell Biology, The Hospital For Sick Children, 686 Bay Street, Toronto, M5G 0A4, Canada; ¶The Arthur and Sonia Labatt Brain Tumour Research Centre, The Hospital For Sick Children, 686 Bay Street, Toronto, M5G 0A4, Canada; ‖Medical Biophysics, University of Toronto, Medical Science Building, Room 4386, 1 King's College Circle, Toronto, ON M5S 1A8, Canada
| | - Michael F Moran
- From the ‡Molecular Structure and Function, The Hospital For Sick Children, 686 Bay Street, Toronto, M5G 0A4, Canada; ‡‡Departments of Molecular Genetics, Medical Science Building, Room 4386, 1 King's College Circle, Toronto, ON M5S 1A8, Canada; **The Princess Margaret Cancer Center, 610 University Avenue, M5G 2M9, Toronto, Canada
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9
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Granum S, Sundvold-Gjerstad V, Gopalakrishnan RP, Berge T, Koll L, Abrahamsen G, Sorlie M, Spurkland A. The kinase Itk and the adaptor TSAd change the specificity of the kinase Lck in T cells by promoting the phosphorylation of Tyr192. Sci Signal 2014; 7:ra118. [DOI: 10.1126/scisignal.2005384] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
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10
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Herpes simplex virus requires VP11/12 to induce phosphorylation of the activation loop tyrosine (Y394) of the Src family kinase Lck in T lymphocytes. J Virol 2009; 83:12452-61. [PMID: 19776125 DOI: 10.1128/jvi.01364-09] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Herpes simplex virus (HSV) tegument proteins are released into the cytoplasm during viral entry and hence are among the first viral proteins encountered by an infected cell. Despite the implied importance of these proteins in the evasion of host defenses, the function of some, like virion protein 11/12 (VP11/12), have not been clearly defined. Previously, we reported that VP11/12 is strongly tyrosine phosphorylated during the infection of lymphocytes but not in fibroblasts or an epithelial cell line (G. Zahariadis, M. J. Wagner, R. C. Doepker, J. M. Maciejko, C. M. Crider, K. R. Jerome, and J. R. Smiley, J. Virol. 82:6098-6108, 2008). We also showed that tyrosine phosphorylation depends in part on the activity of the lymphocyte-specific Src family kinase (SFK) Lck in Jurkat T cells. These data suggested that VP11/12 is a substrate of Lck and that Lck is activated during HSV infection. Here, we show that HSV infection markedly increases the fraction of Lck phosphorylated on its activation loop tyrosine (Y394), a feature characteristic of activated Lck. A previous report implicated the immediate-early protein ICP0 and the viral serine/threonine kinases US3 and UL13 in the induction of a similar activated phenotype of SFKs other than Lck in fibroblasts and suggested that ICP0 interacts directly with SFKs through their SH3 domain. However, we were unable to detect an interaction between ICP0 and Lck in T lymphocytes, and we show that ICP0, US3, and UL13 are not strictly required for Lck activation. In contrast, VP11/12 interacted with Lck or Lck signaling complexes and was strictly required for Lck activation during HSV infection. Thus, VP11/12 likely modulates host cell signaling pathways for the benefit of the virus.
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11
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Ziemba SE, Menard SL, McCabe MJ, Rosenspire AJ. T-cell receptor signaling is mediated by transient Lck activity, which is inhibited by inorganic mercury. FASEB J 2009; 23:1663-71. [PMID: 19168706 DOI: 10.1096/fj.08-117283] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Genetically susceptible rodents exposed to low nontoxic levels of inorganic mercury (Hg(2+)) develop idiosyncratic autoimmune disease associated with defective T-cell function. However, the molecular mechanisms underlying this phenomenon remain mostly unexplained. Brief exposure of T cells to micromolar concentrations of Hg(2+) leads to physiologically relevant nontoxic cellular mercury burdens, and as we have previously reported, attenuates T-cell receptor (TCR) signal strength by approximately 50%. We have found this to be the result of an inadequate activation of the tyrosine kinase ZAP-70, which is hypophosphorylated following TCR stimulation in Hg(2+) burdened cells when compared to untreated controls. In T cells, ZAP-70 phosphorylation is dependent on lymphocyte-specific protein tyrosine kinase (Lck) activity, which in turn is either positively or negatively regulated by the phosphorylation of specific Lck tyrosine residues. In particular, the general belief is that Lck is negatively regulated by phosphorylation of tyrosine 192 (Y192). We now demonstrate by Western blotting that, in Jurkat T cells, TCR signal transduction (and ZAP-70 phosphorylation) was positively associated with a rapid transient phosphorylation of Y192, which was inhibited in cells that were briefly (5 min) exposed to 5 microM Hg(2+). Thus, Hg(2+) inhibits a critical activating role played by Lck Y192 during the most proximal events of the TCR-induced cell signaling.
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Affiliation(s)
- Stamatina E Ziemba
- Department of Immunology and Microbiology, Wayne State University School of Medicine, Detroit, MI 48201, USA
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12
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Soto-Peña GA, Vega L. Arsenic interferes with the signaling transduction pathway of T cell receptor activation by increasing basal and induced phosphorylation of Lck and Fyn in spleen cells. Toxicol Appl Pharmacol 2008; 230:216-26. [PMID: 18407307 DOI: 10.1016/j.taap.2008.02.029] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2007] [Revised: 02/05/2008] [Accepted: 02/20/2008] [Indexed: 11/18/2022]
Abstract
Arsenic is known to produce inhibition as well as induction of immune cells proliferative responses depending on the doses as one of its mechanisms of immunotoxicity. Here we evaluate the effect of arsenic exposure on the activation of splenic mononuclear cells (SMC) in male CD57BL6N mice. Intra-gastric exposure to arsenic (as sodium arsenite) for 30 days (1, 0.1, or 0.01 mg/kg/day), reduced the proportion of CD4+ cells and the CD4+/CD8+ ratio in the spleen, increasing the proportion of CD11b+ cells. Arsenic exposure did not modify the proportion of B cells. SMC showed an increased level of phosphorylation of lck and fyn kinases (first kinases associated to TCR complex when activated). Although normal levels of apoptosis were observed on freshly isolated SMC, an increase in apoptotic cells related with the increase in phosphorylation of lck and fyn was observed when SMC were activated with Concanavalin-A (Con-A). Arsenic exposure reduced the proliferative response of SMC to Con-A, and also reduced secretion of IL-2, IL-6, IL-12 and IFNgamma. No effect was observed on IL-4, and IL-10 secretion. The same effects were observed when SMC of exposed animals were activated with anti-CD3/CD28 antibodies for 24 h, but these effects were transitory since a recovery, up to control levels or even higher, were observed after 72 h of stimulation. This study demonstrates that repeated and prolonged exposure to arsenic alters cell populations and produces functional changes depending on the specific activation pathway, and could be related with the phosphorylation status of lck and fyn kinases.
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Affiliation(s)
- Gerson A Soto-Peña
- Sección Externa de Toxicología, CINVESTAV, Av. IPN 2508, San Pedro Zacatenco, México D. F., 07360, Mexico
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13
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Tapinos N, Rambukkana A. Insights into regulation of human Schwann cell proliferation by Erk1/2 via a MEK-independent and p56Lck-dependent pathway from leprosy bacilli. Proc Natl Acad Sci U S A 2005; 102:9188-93. [PMID: 15967991 PMCID: PMC1166596 DOI: 10.1073/pnas.0501196102] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Activation of extracellular signal-regulated kinase (Erk) 1/2, which plays a critical role in diverse cellular processes, including cell proliferation, is known to be mediated by the canonical Raf-mitogen-activated protein kinase kinase (MEK) kinase cascade. Alternative MEK-independent signaling pathways for Erk1/2 activation in mammalian cells are not known. During our studies of human primary Schwann cell response to long-term infection of Mycobacterium leprae, the causative organism of leprosy, we identified that intracellular M. leprae activated Erk1/2 directly by lymphoid cell kinase (p56Lck), a Src family member, by means of a PKCepsilon-dependent and MEK-independent signaling pathway. Activation of this signaling induced nuclear accumulation of cyclin D1, G1/S-phase progression, and continuous proliferation, but without transformation. Thus, our data reveal a previously unknown signaling mechanism of glial cell proliferation, which might play a role in dedifferentiation as well as nerve regeneration and degeneration. Our findings may also provide a potential mechanism by which an obligate intracellular bacterial pathogen like M. leprae subverts nervous system signaling to propagate its cellular niche for colonization and long-term bacterial survival.
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Affiliation(s)
- Nikos Tapinos
- Laboratory of Bacterial Pathogenesis and Immunology, The Rockefeller University, Bronk Building Room 501, 1230 York Avenue, New York, NY 10021, USA
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14
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Byrd VM, Kilkenny DM, Dikov MM, Reich MB, Rocheleau JV, Armistead WJ, Thomas JW, Miller GG. Fibroblast growth factor receptor‐1 interacts with the T‐cell receptor signalling pathway. Immunol Cell Biol 2003; 81:440-50. [PMID: 14636241 DOI: 10.1046/j.1440-1711.2003.01199.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Fibroblast growth factor receptors are expressed by some T cells, and provide costimulation for these cells. Such receptors allow T cells to respond to fibroblast growth factors expressed in response to injury and inflammation and may provide a mechanism for 'context-dependent' responses to antigens within the local microenvironment. The mechanisms by which fibroblast growth factor receptors might interact with the TCR signalling pathway are not defined. Here we show that the TCR and fibroblast growth factor receptors co-localize during combined stimulation. Signalling via fibroblast growth factor receptors alone results in phosphorylation of Lck and induces nuclear translocation of nuclear factors of activated T cells. Combined stimulation via fibroblast growth factor receptors and the TCR synergistically enhances the activation of nuclear factors of activated T cells. The results suggest that peptide growth factors produced at sites of injury and inflammation can contribute to the outcome of T-cell encounters with antigen.
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Affiliation(s)
- Victor M Byrd
- Department of Medicine, Vanderbilt University Medical School, Nashville, USA
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15
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Kesavan KP, Isaacson CC, Ashendel CL, Geahlen RL, Harrison ML. Characterization of the in vivo sites of serine phosphorylation on Lck identifying serine 59 as a site of mitotic phosphorylation. J Biol Chem 2002; 277:14666-73. [PMID: 11847223 DOI: 10.1074/jbc.m111911200] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The lymphocyte-specific protein-tyrosine kinase Lck plays a critical role in T cell activation. In response to T cell antigen receptor binding Lck undergoes phosphorylation on serine residues that include serines 59 and 194. Serine 59 is phosphorylated by ERK mitogen-activated protein kinase. Recently, we showed that in mitotic T cells Lck becomes hyper-phosphorylated on serine residues. In this report, using one-dimensional phosphopeptide mapping analysis, we identify serine 59 as a site of in vivo mitotic phosphorylation in Lck. The mitotic phosphorylation of serine 59 did not require either the catalytic activity or functional SH2 or SH3 domains of Lck. In addition, the presence of ZAP-70 also was dispensable for the phosphorylation of serine 59. Although previous studies demonstrated that serine 59 is a substrate for the ERK MAPK pathway, inhibitors of this pathway did not block the mitotic phosphorylation of serine 59. These results identify serine 59 as a site of mitotic phosphorylation in Lck and suggest that a pathway distinct from that induced by antigen receptor signaling is responsible for its phosphorylation. Thus, the phosphorylation of serine 59 is the result of two distinct signaling pathways, differentially activated in response to the physiological state of the T cell.
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Affiliation(s)
- Kamala P Kesavan
- Department of Biological Sciences, Purdue University, West Lafayette, Indiana 47907, USA
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16
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Holdorf AD, Lee KH, Burack WR, Allen PM, Shaw AS. Regulation of Lck activity by CD4 and CD28 in the immunological synapse. Nat Immunol 2002; 3:259-64. [PMID: 11828322 DOI: 10.1038/ni761] [Citation(s) in RCA: 161] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Although the Src family tyrosine kinase Lck is essential for T cell receptor (TCR) signaling, whether or how Lck is activated is unknown. Using a phosphospecific antiserum to Lck, we show here that Lck becomes autophosphorylated when T cells are stimulated by antigen-presenting cells (APCs). We found that TCR cross-linking alone could not stimulate Lck autophosphorylation and CD45 was not required for this process. Instead, the T cell accessory molecules CD4 and CD28 cooperated to induce autophosphorylation of Lck. CD4 recruited Lck to the T cell--APC interface, whereas CD28 sustained Lck activation. These data show how the multiple interactions afforded by the immunological synapse drive efficient and highly specific signaling.
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Affiliation(s)
- Amy D Holdorf
- Department of Pathology and Immunology, Washington University School of Medicine, 660 S. Euclid, Campus Box 8118, St. Louis, MO 63110, USA
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17
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Lafont V, Liautard J, Sable-Teychene M, Sainte-Marie Y, Favero J. Isopentenyl pyrophosphate, a mycobacterial non-peptidic antigen, triggers delayed and highly sustained signaling in human gamma delta T lymphocytes without inducing eown-modulation of T cell antigen receptor. J Biol Chem 2001; 276:15961-7. [PMID: 11278429 DOI: 10.1074/jbc.m008684200] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The Vgamma9Vdelta2 T cell subset, which represents up to 90% of the circulating gammadelta T cells in humans, was shown to be activated, via the T cell receptor (TcR), by non-peptidic phosphorylated small organic molecules. These phosphoantigens, which are not presented by professional antigen-presenting cells, induce production of high amounts of interferon-gamma and tumor necrosis factor (TNF-alpha). To date, the specific signals triggered by these antigens have not been characterized. Here we analyze proximal and later intracellular signals triggered by isopentenyl pyrophosphate (IPP), a mycobacterial antigen that specifically stimulates Vgamma9Vdelta2 T cells, and compare these to signals induced by the non-physiological model using an anti-CD3 antibody. During antigenic stimulation we noticed that, except for the proximal p56(lck) signal, which is triggered early, the signals appear to be delayed and highly sustained. This delay, which likely accounts for the delay observed in TNF-alpha production, is discussed in terms of the ability of the antigen to cross-link and recruit transducing molecules mostly anchored to lipid rafts. Moreover, we demonstrate that, in contrast to anti-CD3 antibody, IPP does not induce down-modulation of the TcR.CD3 complex, which likely results in the highly sustained signaling and release of high levels of TNF-alpha.
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MESH Headings
- Antigens, Bacterial/pharmacology
- Cells, Cultured
- Down-Regulation/drug effects
- Hemiterpenes
- Humans
- Kinetics
- Lymphocyte Specific Protein Tyrosine Kinase p56(lck)/metabolism
- Mitogen-Activated Protein Kinase 1/metabolism
- Mitogen-Activated Protein Kinase 3
- Mitogen-Activated Protein Kinases/metabolism
- Mycobacterium/immunology
- Organophosphorus Compounds/pharmacology
- Phosphorylation
- Protein-Tyrosine Kinases/metabolism
- Receptors, Antigen, T-Cell/drug effects
- Receptors, Antigen, T-Cell/immunology
- Receptors, Antigen, T-Cell, gamma-delta/drug effects
- Receptors, Antigen, T-Cell, gamma-delta/immunology
- Signal Transduction/drug effects
- Signal Transduction/immunology
- T-Lymphocytes/drug effects
- T-Lymphocytes/immunology
- Tumor Necrosis Factor-alpha/biosynthesis
- ZAP-70 Protein-Tyrosine Kinase
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Affiliation(s)
- V Lafont
- INSERM U431, Microbiologie et Pathologie Cellulaire Infectieuse, Université Montpellier 2, Place Eugène Bataillon, cc 100, Montpellier 34095, cedex 5, France
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18
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Abstract
T lymphocyte activation is triggered through the CD3-TCR complex or the CD2 molecule. Beside common biochemical events, we previously showed that a 62-kDa protein associated with PLCgamma-1 and p21RasGAP was specifically tyrosine phosphorylated after CD2 stimulation in Jurkat T cells. We demonstrated here that it was identical to p62Dok, a docking protein highly phosphorylated in human chronic myelogenous leukemia cells and in murine abl-transformed B cells. Mainly, we showed that p62Dok tyrosine phosphorylation was strengthened by the functional interplay between CD3 and CD2. Primary stimulation of Jurkat cells via CD3 suppressed most of the subsequent CD2-dependent phosphorylation events, except p62Dok tyrosine phosphorylation, which was on the contrary strongly increased. Kinetic studies indicated that a short treatment with anti-CD3 was sufficient to amplify the CD2-induced tyrosine phosphorylation of p62Dok. By contrast, CD2-induced PLCgamma-1 tyrosine phosphorylation and calcium response progressively diminished. Finally, enhanced amounts of tyrosine phosphorylated p62Dok were recruited to p21RasGAP and PLCgamma-1 after CD2 stimulation in CD3-activated cells. CD3 stimulation is known to enhance CD2 avidity for its ligand and to induce the binding of the CD2AP protein to the CD2 cytoplasmic tail. Our results suggest that the CD3-TCR complex rapidly primes the CD2 pathway to activate one of its specific components, p62Dok.
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Affiliation(s)
- J Harriague
- Laboratoire d'Immunologie Cellulaire, CNRS UMR 7627, Hôpital Pitié-Salpêtrière, Paris, France
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19
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Liu Y, Liu YC, Meller N, Giampa L, Elly C, Doyle M, Altman A. Protein Kinase C Activation Inhibits Tyrosine Phosphorylation of Cbl and Its Recruitment of Src Homology 2 Domain-Containing Proteins. THE JOURNAL OF IMMUNOLOGY 1999. [DOI: 10.4049/jimmunol.162.12.7095] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Abstract
One of the major proteins that is rapidly tyrosine phosphorylated upon stimulation of the TCR/CD3 complex is the 120-kDa product of the c-cbl protooncogene (Cbl). Upon activation, tyrosine-phosphorylated Cbl interacts with the Src homology 2 (SH2) domains of several signaling proteins, e.g., phosphatidylinositol 3-kinase (PI3-K) and CrkL. In the present study, we report that pretreatment of Jurkat T cells with PMA reduced the anti-CD3-induced tyrosine phosphorylation of Cbl and, consequently, its activation-dependent association with PI3-K and CrkL. A specific protein kinase C (PKC) inhibitor (GF-109203X) reversed the effect of PMA on tyrosine phosphorylation of Cbl and restored the activation-dependent association of Cbl with PI3-K and CrkL. We also provide evidence that PKCα and PKCθ can physically associate with Cbl and are able to phosphorylate it in vitro and in vivo. Furthermore, a serine-rich motif at the C terminus of Cbl, which is critical for PMA-induced 14-3-3 binding, is also phosphorylated by PKCα and PKCθ in vitro. These results suggest that, by regulating tyrosine and serine phosphorylation of Cbl, PKC is able to control the association of Cbl with signaling intermediates, such as SH2 domain-containing proteins and 14-3-3 proteins, which may consequently result in the modulation of its function.
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Affiliation(s)
- Yuhong Liu
- Division of Cell Biology, La Jolla Institute for Allergy and Immunology, San Diego, CA 92121
| | - Yun-Cai Liu
- Division of Cell Biology, La Jolla Institute for Allergy and Immunology, San Diego, CA 92121
| | - Nahum Meller
- Division of Cell Biology, La Jolla Institute for Allergy and Immunology, San Diego, CA 92121
| | - Leslie Giampa
- Division of Cell Biology, La Jolla Institute for Allergy and Immunology, San Diego, CA 92121
| | - Chris Elly
- Division of Cell Biology, La Jolla Institute for Allergy and Immunology, San Diego, CA 92121
| | - Melissa Doyle
- Division of Cell Biology, La Jolla Institute for Allergy and Immunology, San Diego, CA 92121
| | - Amnon Altman
- Division of Cell Biology, La Jolla Institute for Allergy and Immunology, San Diego, CA 92121
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20
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Franklin RA, Mcleod A, Robinson PJ. Calcium-induced p56(Lck) phosphorylation in human T lymphocytes via calmodulin dependent kinase. Biochem Biophys Res Commun 1999; 259:283-6. [PMID: 10362499 DOI: 10.1006/bbrc.1999.0778] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We report that stimulation of both primary human and Jurkat T lymphocytes with the calcium ionophore ionomycin, or A23187, results in the phosphorylation of p56(Lck) as determined by shifts in mobility of p56(Lck) on immunoblots. The shifts in the mobility of p56(Lck) induced by ionomycin could be blocked by preincubation of the cells with EGTA, demonstrating the requirement for extracellular calcium in this response. Although increases in intracellular calcium have been shown to modulate CD45 activity, phosphorylation of p56(Lck) was not mediated via CD45. Ionomycin stimulation of J45. 01 cells, a CD45-negative Jurkat cell derivative, also resulted in p56(Lck) mobility shifts. Instead, this response appears to be mediated via a calmodulin-dependent kinase. This response could be blocked by calmidazolium, an inhibitor of calmodulin, and KN-93, an inhibitor of calmodulin-dependent kinases (CaM-Kinase). KN-92, an inactive analog of KN-93, failed to block this response. These studies demonstrate a new role for calcium and CaM-Kinase in human T-lymphocytes and describe a novel mechanism by which p56(Lck) can be modulated.
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Affiliation(s)
- R A Franklin
- Department of Microbiology and Immunology, East Carolina University School of Medicine, Greenville, North Carolina, 27858, USA
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21
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Gatti A, Traugh JA. A two-dimensional peptide gel electrophoresis system for phosphopeptide mapping and amino acid sequencing. Anal Biochem 1999; 266:198-204. [PMID: 9888976 DOI: 10.1006/abio.1998.2955] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
A novel two-dimensional electrophoresis system to be carried out on polyacrylamide gels under nondenaturing conditions was developed to efficiently fractionate the peptides resulting from endoproteinase digestion of 32P-labeled proteins. In particular, nondenaturing gel isoelectric focusing was combined with alkaline 40% polyacrylamide gel electrophoresis to generate phosphopeptide maps with high reproducibility, thus allowing both protein fingerprinting and comparative analysis of different samples. The potential application of this method for subsequent amino acid sequencing of the isolated phosphopeptides was further demonstrated by successful manual and automated Edman sequencing. Taken together these data show that such a simple and precise approach is suitable for both analytical and preparative aims.
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Affiliation(s)
- A Gatti
- Department of Biochemistry, University of California, Riverside, California, 92521,
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22
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Czyzyk JK, Fernsten PD, Brtva TR, Der CJ, Winfield JB. CD45 and Src-related protein tyrosine kinases regulate the T cell response to phorbol esters. Biochem Biophys Res Commun 1998; 243:444-50. [PMID: 9480828 DOI: 10.1006/bbrc.1998.8114] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Protein kinase C (PKC)-dependent activation of the Ras signal transduction cascade is essential for induction of the IL-2 promoter during stimulation of T lymphocytes via the T cell receptor (TCR). In this study, the effects of PKC-activating phorbol myristate acetate (PMA) on Ras-dependent activation of transcription from the ets/AP-1 Ras-responsive promoter element were examined in human T cells. Pretreatment of Jurkat cells with the Src-family PTK inhibitor herbimycin A resulted in a 50% inhibition of transactivation of the reporter following incubation with PMA. Evidence was also obtained to suggest the participation of the leukocyte-specific protein tyrosine phosphatase CD45, a regulator of Src-like PTKs, in the PMA-induced activation of the Ras/Raf pathway. First, PMA-induced transactivation of ets/AP-1 is diminished 75% in CD45-negative variants, compared with CD45-positive cells. Second, engagement of CD45 by monoclonal antibodies suppresses the PMA response from the reporter construct. Taken together, these data suggest that Src-related proteins mediate PKC-dependent activation of the Ras/Raf pathway and implicate CD45 in the TCR-independent activation of T lymphocytes induced by agents such as PMA.
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Affiliation(s)
- J K Czyzyk
- Division of Rheumatology and Immunology, Thurston Arthritis Research Center, Chapel Hill, NC 27599-7280, USA
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23
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Abstract
Src family protein tyrosine kinases are activated following engagement of many different classes of cellular receptors and participate in signaling pathways that control a diverse spectrum of receptor-induced biological activities. While several of these kinases have evolved to play distinct roles in specific receptor pathways, there is considerable redundancy in the functions of these kinases, both with respect to the receptor pathways that activate these kinases and the downstream effectors that mediate their biological activities. This chapter reviews the evidence implicating Src family kinases in specific receptor pathways and describes the mechanisms leading to their activation, the targets that interact with these kinases, and the biological events that they regulate.
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Affiliation(s)
- S M Thomas
- Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts 02115, USA.
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24
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Lafont V, Hivroz C, Carayon P, Dornand J, Favero J. The lectin jacalin specifically triggers cell signaling in CD4+ T lymphocytes. Cell Immunol 1997; 181:23-9. [PMID: 9344492 DOI: 10.1006/cimm.1997.1191] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The lectin jacalin was shown to specifically stimulate CD4(+) lymphocytes. This lectin, which presents a peptide highly similar to a sequence of the HIV external glycoprotein, interacts with CD4 and is able to inhibit in vitro HIV infection. Since jacalin binds also CD8, its mitogenic specificity cannot exclusively be attributed to its interaction with CD4. We therefore hypothesized that the lectin could trigger signals specifically associated with CD4. Here we show that jacalin triggers IL2 gene transcription only in CD4(+) lymphocytes. In parallel, we show that numerous proteins are tyrosine phosphorylated in this cell subset while only a restricted number of them are phosphorylated in CD8(+) cells. Moreover, we show that the tyrosine kinase p56lck, which is associated with both CD4 and CD8, is activated only in CD4(+) lymphocytes, making this lectin a good model for the study of cell signaling triggered in this restricted subpopulation.
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Affiliation(s)
- V Lafont
- Microbiologie et Pathologie Cellulaire Infectieuse, Université de Montpellier II, Place Eugène Bataillon, cc 100, Montpellier cedex 05, 34095, France
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25
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Lafont V, Fischer T, Zumbihl R, Faure S, Hivroz C, Rouot B, Favero J. Evidence for a CD4-associated calcium influx independent of the phosphoinositide transduction pathway in human T cells. Eur J Immunol 1997; 27:2261-8. [PMID: 9341768 DOI: 10.1002/eji.1830270921] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
We recently showed, using human Jurkat T cell variants lacking the T cell receptor (TCR)/CD3 complex, that the lectin jacalin is able to trigger intracellular calcium increase provided that CD4 is expressed on the cell surface. Involvement of the CD4 molecule in jacalin-induced biological effects was furthermore demonstrated in differentiated U937 myelomonocytic cells expressing or not expressing CD4, and is confirmed here in human CD4-transfected mouse thymoma cells. In the present paper, we analyze the CD4-associated calcium response triggered by jacalin independently of the TCR/CD3 complex. We show that the observed calcium rise results from a direct long-lasting calcium influx from the outside without release of calcium from intracellular stores. We demonstrate that it is independent of the phosphoinositide phospholipase C transduction pathway. Moreover, we show that this peculiar calcium response can be blocked by protein tyrosine kinase inhibitors (herbimycin and genistein) giving evidence of the involvement of a protein tyrosine kinase, the best candidate of which is the CD4-associated p56lck. Altogether, our results suggest that, independently of the TCR/CD3 complex, CD4 may be involved in the triggering of a calcium signal dependent on a protein tyrosine kinase and independent of the phosphoinositide transduction pathway.
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Affiliation(s)
- V Lafont
- Institut National de la Santé et de la Recherche Médicale (INSERM) U431, Université de Montpellier II, France
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26
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Galron D, Ansotegui IJ, Isakov N. Posttranslational regulation of Lck and a p36-38 protein by activators of protein kinase C: differential effects of the tumor promoter, PMA, and the non-tumor-promoter, bryostatin. Cell Immunol 1997; 178:141-51. [PMID: 9225005 DOI: 10.1006/cimm.1997.1120] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
T cell activation via the antigen receptor or by PKC-activating drugs results in phosphorylation of Lck and alteration of its electrophoretic mobility. Although tyrosine phosphorylation appears to regulate Lck enzymatic activity, the significance of phosphorylation of serine residues and its relevance to the cell proliferation process are yet unclear. We found that the PKC activator, bryostatin, like PMA, induced the conversion of p56lck to a slower migrating form with an apparent molecular mass of 60 kDa. The effect of PMA lasted over 48 hr but that of bryostatin was transient and correlated in time kinetics with that of the bryostatin-induced degradation of PKC. The effects of bryostatin were dominant over those of PMA. In addition, PKC was found to affect both serine and tyrosine phosphorylation of Lck but had no significant effect on the in vitro catalytic activity of Lck. To test whether serine phosphorylation of Lck may affect its ability to bind tyrosine phosphoproteins, we compared Lck immunoprecipitates from PMA- and bryostatin-treated T cells. We found that a 36- to 38-kDa tyrosine phosphoprotein co-immunoprecipitated with Lck from cells that were treated for 24 hr with PMA, but not bryostatin. A p36-38 from PMA- but not bryostatin-treated cells also interacted with an Lck-SH2 fusion protein, suggesting differential regulation of p36-38 by PMA and bryostatin. Furthermore, in vitro phosphorylation of p36-38 occurred in lysates of cells that were treated for 24 hr with PMA, but not in lysates of bryostatin-treated cells. The results show that tyrosine phosphorylation and the association of p36-38 with Lck are differentially affected by bryostatin and PMA and suggest that PKC regulates the interaction of potential signaling molecules with Lck, thereby regulating biochemical events that are relevant to T cell mitogenesis and/or transformation.
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Affiliation(s)
- D Galron
- Department of Microbiology and Immunology, Faculty of Health Sciences, Ben Gurion University of the Negev, Beer Sheva, Israel
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27
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Gervais FG, Veillette A. Reconstitution of interactions between protein-tyrosine phosphatase CD45 and tyrosine-protein kinase p56(lck) in nonlymphoid cells. J Biol Chem 1997; 272:12754-61. [PMID: 9139734 DOI: 10.1074/jbc.272.19.12754] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
To further understand the functional interactions between CD45 and p56(lck) in T-cells, we stably reconstituted their expression in a nonlymphoid system. The results of our analyses demonstrated that CD45 could dephosphorylate tyrosine 505 of p56(lck) in NIH 3T3 fibroblasts. As is the case for T-cells, removal of the unique domain of p56(lck) interfered with dephosphorylation of tyrosine 505 in fibroblasts, further stressing the importance of this region in the interactions between CD45 and p56(lck). The ability of CD45 to dephosphorylate tyrosine 505 in NIH 3T3 cells was also greatly influenced by the catalytic activity of p56(lck). Indeed, whereas CD45 provoked dephosphorylation of kinase-defective Lck molecules in this system, it failed to stably dephosphorylate kinase-active p56(lck) polypeptides. Finally, our studies showed that CD45 was also able to inhibit the oncogenic potential of a constitutively activated version of p56(lck) in NIH 3T3 cells. This effect did not require the Lck unique domain and apparently resulted from selective dephosphorylation of substrates of activated p56(lck) in fibroblasts. In addition to providing insights into the nature and regulation of the interactions between CD45 and p56(lck) in T-cells, these results indicated that CD45 clearly has the capacity to both positively and negatively regulate p56(lck)-mediated functions in vivo.
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Affiliation(s)
- F G Gervais
- McGill Cancer Centre, McGill University, Montreal, Quebec H3G 1Y6, Canada
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28
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Pathan NI, Geahlen RL, Harrison ML. The protein-tyrosine kinase Lck associates with and is phosphorylated by Cdc2. J Biol Chem 1996; 271:27517-23. [PMID: 8910336 DOI: 10.1074/jbc.271.44.27517] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
The protein-tyrosine kinase Lck is essential for signaling through the T-cell antigen receptor. Treatment of T-cells with a variety of extracellular stimuli increases the phosphorylation of Lck on serine residues. This results in shifts in the apparent molecular weight of Lck to forms that exhibit reduced electrophoretic mobility on SDS-polyacrylamide gels. We found that as a result of arresting cells in mitosis, forms of Lck were generated that migrated with slower mobilities on SDS-polyacrylamide gels. This suggested that a serine/threonine kinase, active at mitosis, was phosphorylating Lck. Using antibodies to Lck and to the cyclin-dependent serine kinase, Cdc2, as well as the cyclin-dependent kinase affinity resin, Suc1-agarose, we detected a stable interaction between Lck and Cdc2. The interaction was mediated through the Src homology 3 domain of Lck and was selective, as only the active form of Cdc2 was found to associate with Lck. Moreover, Cdc2 was able to phosphorylate Lck in vitro and shift its electrophoretic mobility to a more slowly migrating form. An association between active Cdc2 and the Src-related kinases Lyn and Fyn was also demonstrated, although Cdc2 was not found associated with the tyrosine kinases, Csk and Syk. These results demonstrate that at mitosis, Cdc2 associates with and phosphorylates Lck.
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Affiliation(s)
- N I Pathan
- Department of Biology, Purdue University, West Lafayette, Indiana 47907, USA
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29
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Couture C, Songyang Z, Jascur T, Williams S, Tailor P, Cantley LC, Mustelin T. Regulation of the Lck SH2 domain by tyrosine phosphorylation. J Biol Chem 1996; 271:24880-4. [PMID: 8798764 DOI: 10.1074/jbc.271.40.24880] [Citation(s) in RCA: 70] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Src homology 2 (SH2) domains bind to phosphotyrosine (Tyr(P)) residues in specific sequence contexts in other proteins and thereby mediate tyrosine phosphorylationdependent protein-protein interactions. The SH2 domain of the Src family kinase Lck is phosphorylated at tyrosine 192 in T cells upon T cell antigen receptor triggering. We have studied the consequences of this phosphorylation on the properties of the SH2 domain and on the function of Lck in T cell activation. We report that phosphorylation at Tyr192 reduced the capacity of the isolated SH2 domain to bind a high affinity peptide ligand and Tyr(P)-containing cellular proteins. This effect was mimicked by mutation of Tyr192 to an acidic residue. In intact T cells, where Lck participates in T cell antigen receptor signal transduction in an SH2 domain-dependent manner, phosphorylation of Tyr192 correlated with reduced downstream signaling. Our results indicate that tyrosine phosphorylation of the SH2 domain of Lck terminates its high affinity binding to ligands, thereby negatively regulating its participation in T cell antigen receptor signaling. This represents a novel mechanism for the regulation of the function of SH2 domains.
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Affiliation(s)
- C Couture
- Division of Cell Biology, La Jolla Institute for Allergy and Immunology, La Jolla, California 92037, USA
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30
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Marie-Cardine A, Fischer S, Gorvel JP, Maridonneau-Parini I. Recruitment of activated p56lck on endosomes of CD2-triggered T cells, colocalization with ZAP-70. J Biol Chem 1996; 271:20734-9. [PMID: 8702825 DOI: 10.1074/jbc.271.34.20734] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
We have previously established that upon CD2 activation of T cells, p56(lck) showed a transient increase in its kinase activity and was partially internalized. Here we studied the possibility that p56(lck) could retain its kinase activity in the endosomes of CD2-triggered cells. T cells were fractionated on a sucrose gradient, and the endosomal fraction was isolated. In CD2-triggered cells, part of Lck was internalized and presented a maximal kinase activity in the endosome-enriched fraction after 5 min, decreasing thereafter. In the endosomal fraction of activated cells, four tyrosine-phosphorylated proteins of apparent molecular masses of 30, 40, 56, and 70 kDa were detected. We demonstrated that the protein tyrosine kinase ZAP-70 was recruited to the endosomal fraction upon CD2 stimulation with kinetics similar to that of p56(lck), suggesting that recruitment of protein tyrosine kinases to endosomal vesicles could promote specific transduction signals at the intracellular level.
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Affiliation(s)
- A Marie-Cardine
- INSERM U332, Institut Cochin de Génétique Moléculaire, 75014 Paris
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31
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Duplay P, Alcover A, Fargeas C, Sékaly RP, Branton PE. An activated epidermal growth factor receptor/Lck chimera restores early T cell receptor-mediated calcium response in a CD45-deficient T cell line. J Biol Chem 1996; 271:17896-902. [PMID: 8663450 DOI: 10.1074/jbc.271.30.17896] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
In T cells, cell surface expression of CD45, a transmembrane tyrosine phosphatase, is required for T cell receptor (TCR) signal transduction. Indirect evidence suggests that CD45 function in TCR signaling involves the dephosphorylation of the C-terminal negative regulatory site of p56(lck), Tyr-505. To evaluate the importance of CD45-mediated dephosphorylation of p56(lck) Tyr-505 in TCR signaling, we established CD45(-) Jurkat cell lines expressing various forms of a chimera containing the extracellular and transmembrane domains of the epidermal growth factor receptor (EGFR) fused to p56(lck). We report that an activated EGFR/Lck chimera is able to reconstitute a Ca2+ response after CD3 stimulation in the absence of CD45 expression. In addition, the wild-type and kinase inactive versions of the EGFR/Lck chimera fail to restore early signaling. Restoration of the response by EGFR/LckF505 required EGF binding to the chimeric kinase. Altogether, these results provide the first direct evidence that the lack of efficient dephosphorylation of p56(lck) Tyr-505 is, in part, responsible for the unresponsiveness of CD45(-) cells. They also indicate that a second event is required for p56(lck) function in TCR signaling in addition to its dephosphorylation at Tyr-505.
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Affiliation(s)
- P Duplay
- Department of Biochemistry, McIntyre Medical Sciences Building, McGill University, Montréal, Québec H3G 1Y6, Canada
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32
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Abstract
Src is the best understood member of a family of 9 tyrosine kinases that regulates cellular responses to extracellular stimuli. Activated mutants of Src are oncogenic. Using Src as an example, and referring to other Src family members where appropriate, this review describes the structure of Src, the functions of the individual domains, the regulation of Src kinase activity in the cell, the selection of substrates, and the biological functions of Src. The review concentrates on developments in the last 6-7 years, and cites data resulting from the isolation and characterization of Src mutants, crystallographic studies of the structures of SH2, SH3 and tyrosine kinase domains, biochemical studies of Src kinase activity and binding properties, and the biology of transgenic and knockout mouse strains.
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Affiliation(s)
- M T Brown
- Fred Hutchinson Cancer Research Center, Seattle, WA 98104, USA
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33
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Stover DR, Furet P, Lydon NB. Modulation of the SH2 binding specificity and kinase activity of Src by tyrosine phosphorylation within its SH2 domain. J Biol Chem 1996; 271:12481-7. [PMID: 8647855 DOI: 10.1074/jbc.271.21.12481] [Citation(s) in RCA: 61] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
The Src family of kinases are held in an inactive state by interaction of their SH2 domain with a C-terminal phosphotyrosine. Dephosphorylation of this site can reactivate Src; however, recent evidence suggests that activation can also occur without dephosphorylation. In this study, platelet-derived growth factor receptor phosphorylation of Src on Tyr-213 specifically blocked binding of its SH2 domain to a phosphopeptide corresponding to the C-terminal regulatory sequence, while binding to other sequences, such as the platelet-derived growth factor receptor or a peptide from the epidermal growth factor receptor, was unaffected. Consequently, Src was activated over 50-fold. This is the first demonstration of regulation of a SH2 domain specificity by post-translational modification and is likely to be a general mechanism for regulation of all Src-like kinases.
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Affiliation(s)
- D R Stover
- Pharmaceutical Research Division, Ciba-Geigy Limited, Basel, Switzerland
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34
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Bougeret C, Delaunay T, Romero F, Jullien P, Sabe H, Hanafusa H, Benarous R, Fischer S. Detection of a physical and functional interaction between Csk and Lck which involves the SH2 domain of Csk and is mediated by autophosphorylation of Lck on tyrosine 394. J Biol Chem 1996; 271:7465-72. [PMID: 8631775 DOI: 10.1074/jbc.271.13.7465] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
The COOH-terminal Src kinase (Csk) is responsible for the phosphorylation of the conserved, negative regulatory, carboxyl-terminal tyrosine of most of the Src family protein tyrosine kinases. Up to now, no stable binding of Csk to Src kinases has been detected. We therefore decided to analyze this interaction using two systems which allow detection of transient interaction. We produced and purified recombinant proteins in the glutathione S-transferase prokaryotic expression system. First, using real-time biospecific interaction analysis (BIAcore(TM)), we detected in vitro a specific interaction between Csk and one of its substrates Lck, a lymphocyte-specific member of the Src family. This interaction requires the autophosphorylation of Lck on tyrosine 394 (the phosphorylation of which is correlated with an increase of the kinase activity) and involves a functional Csk SH2 domain. Second, using the yeast two-hybrid system, we confirmed in vivo the physical interaction between Csk and Lck. Furthermore, in vitro we showed that autophosphorylation of Lck on tyrosine 394 enhances the phosphorylation of Lck by Csk on the negative regulatory site, tyrosine 505, suggesting that activated Lck serves preferentially as substrate for Csk. These findings might explain the mechanism(s) by which Csk interacts with most of Src kinases to down-regulate their kinase activity.
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Affiliation(s)
- C Bougeret
- INSERM, Institut Cochin de Génétique Moleculaire/Université Paris, France
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35
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Brumell JH, Burkhardt AL, Bolen JB, Grinstein S. Endogenous reactive oxygen intermediates activate tyrosine kinases in human neutrophils. J Biol Chem 1996; 271:1455-61. [PMID: 8576138 DOI: 10.1074/jbc.271.3.1455] [Citation(s) in RCA: 112] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
In response to invading microorganisms, neutrophils produce large amounts of superoxide and other reactive oxygen intermediates (ROI) by assembly and activation of a multicomponent enzyme complex, the NADPH oxidase. While fulfilling a microbicidal role, ROI have also been postulated to serve as signaling molecules, because activation of the NADPH oxidase was found to be associated with increased tyrosine phosphorylation (Fialkow, L., Chan, C. K., Grinstein, S., and Downey, G.P. (1993) J. Biol. Chem. 268, 17131-17137). The mechanism whereby ROI induces phosphotyrosine accumulation was investigated using electroporated neutrophils stimulated with guanosine 5'-O-3-thiotriphosphate in order to bypass membrane receptors. In vitro immune complex assays and immunoblotting were used to identify five tyrosine kinases present in human neutrophils. Of these, p56/59hck, p72syk, and p77btk were activated during production of ROI. Interestingly, the in vitro autophosphorylation activities of p53/56lyn and p59fgr were found to decline with ROI production. The mode of regulation of p56/59hck was explored in detail. Oxidizing agents were unable to activate p56/59hck in vitro and, once activated in situ, reducing agents failed to inactivate it, suggesting that the effects of ROI are indirect. Tyrosine phosphorylation of p56/59hck paralleled its activation, and dephosphorylation in vitro reversed the stimulation. We therefore conclude that tyrosine phosphorylation is central to the regulation of p56/59hck and likely also of p72syk, which is similarly phosphorylated upon activation of the oxidase. Because ROI have been shown to reduce the activity of tyrosine phosphatases, we suggest that this inhibition allows constitutively active kinases to auto/transphosphorylate on stimulatory tyrosine residues, leading to an increase in their catalytic activity. Enhanced phosphotyrosine accumulation would then result from the combined effects of increased phosphorylation with decreased dephosphorylation.
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Affiliation(s)
- J H Brumell
- Division of Cell Biology, Hospital for Sick Children, Toronto, Ontario, Canada
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36
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Weil R, Veillette A. Signal transduction by the lymphocyte-specific tyrosine protein kinase p56lck. Curr Top Microbiol Immunol 1996; 205:63-87. [PMID: 8575198 DOI: 10.1007/978-3-642-79798-9_4] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Affiliation(s)
- R Weil
- McGill Cancer Centre, McGill University, Montreal, Canada
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37
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Zenner G, Dirk zur Hausen J, Burn P, Mustelin T. Towards unraveling the complexity of T cell signal transduction. Bioessays 1995; 17:967-75. [PMID: 8526891 DOI: 10.1002/bies.950171110] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Activation of resting T lymphocytes through the T cell antigen receptor complex is initiated by critical phosphorylation and dephosphorylation events that regulate the function and interaction of a number of signaling molecules. Key elements in these reactions are members of the Src, Syk and Csk families of protein tyrosine kinases (PTKs) and the phosphotyrosine phosphatases (PTPases) that regulate and/or counteract them, such as CD45. The PTKs can autophosphorylate and phosphorylate each other at multiple sites and, as the result of these interactions, they are induced to phosphorylate other cellular proteins. These phosphorylation events lead to modulation of enzymatic activities and/or serve as binding sites for other signaling molecules having phosphotyrosine-binding Src homology 2 (SH2) domains. As a result, these proteins translocate to the receptor complexes and are juxtaposed to the kinases that phosphorylate them. Some of the SH2-domain-containing polypeptides lack enzymatic activities and, instead, serve as adapter molecules that couple the signal to downstream effectors, such as regulators of the Ras proteins, and further into serine/threonine-specific protein kinase cascades. Through largely unknown steps these reactions lead to the transcription of previously silent genes, activation of lymphocyte effector functions, progression through the cell cycle and cell proliferation.
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Affiliation(s)
- G Zenner
- Roche Research Center, Hoffmann-La Roche Inc., Nutley, NJ 07110-1199, USA
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38
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Hubert P, Bismuth G, Körner M, Debré P. HIV-1 glycoprotein gp120 disrupts CD4-p56lck/CD3-T cell receptor interactions and inhibits CD3 signaling. Eur J Immunol 1995; 25:1417-25. [PMID: 7774645 DOI: 10.1002/eji.1830250542] [Citation(s) in RCA: 27] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Using the CD4+ human T cell clone P28, we demonstrated that the HIV-1 glycoprotein gp120 inhibited CD3-induced inositol trisphosphate production, calcium influx and T cell proliferation. Additionally, gp120 was shown to dissociate the tyrosine kinase p56lck from CD4 in CEM cells, with a concommittant inhibition of CD4-linked kinase activity. We have addressed the question whether disruption of CD4/p56lck or CD4/CD3-T cell receptor interactions, or both, could account for the inhibitory effect of gp120 in P28 cells. By comparing the effects of various anti-CD4 monoclonal antibodies (mAb) with those of gp120, we show that gp120 and IOT4a modulate CD4 expression, and decrease CD4-associated p56lck and CD4-linked kinase activity at the plasma membrane. In contrast, OKT4A and OKT4 anti-CD4 mAb have no inhibitory effect. Interestingly, gp120 also inhibits CD3-induced Lck activation and cellular tyrosine phosphorylation, particularly of phosphoinositide-specific phospholipase C-gamma-1. Kinetic experiments reveal that the inhibitory effect of gp120 on CD3-induced tyrosine phosphorylation appears as early as 30 min, but culminate when CD4-p56lck complexes disappear from the cell surface after 4 h. These results suggest that a negative signal is triggered by gp120 that results, after a few hours, in down-modulation of CD4-p56lck complexes and the impairment of CD3 signaling. Supporting this hypothesis, gp120 inhibits CD3-linked kinase activity as shown by the inhibition of the phosphorylation of CD3 chains, leading to the inhibition of subsequent signal transduction.
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Affiliation(s)
- P Hubert
- Laboratoire d'Immunologie Cellulaire et Tissulaire, CNRS URA 625, Paris, France
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39
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Abstract
The specificity of immune responses depends upon the activation of only those lymphocytes that recognize the introduced antigen. In recent years, a great deal has been learned about the structure of lymphocyte receptors for antigens and about their signal transduction mechanism. These receptors activate intracellular protein tyrosine kinases of at least two families, the Src family and the Syk/ZAP-70 family. Recent studies have given us considerable insight into the interactions of these two types of kinases and how they mediate antigen receptor signaling.
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Affiliation(s)
- A L DeFranco
- Department of Microbiology and Immunology, University of California, San Francisco 94143-0552, USA
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40
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Oetken C, von Willebrand M, Marie-Cardine A, Pessa-Morikawa T, Ståhls A, Fisher S, Mustelin T. Induction of hyperphosphorylation and activation of the p56lck protein tyrosine kinase by phenylarsine oxide, a phosphotyrosine phosphatase inhibitor. Mol Immunol 1994; 31:1295-302. [PMID: 7997241 DOI: 10.1016/0161-5890(94)90047-7] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
The T cell protein tyrosine kinase p56lck is implicated in thymic development and mitogenic activation of T lymphocytes, and is itself regulated by reversible tyrosine phosphorylation. When phenylarsine oxide (PAO), a membrane-permeable inhibitor of phosphotyrosine phosphatases, was added to Jurkat T leukemia or LSTRA thymoma cells, the phosphate content of p56lck increased rapidly. The sites of increased phosphorylation were mapped to Tyr-192, Tyr-394 and Tyr-505. Hyperphosphorylated p56lck displayed retarded mobility on SDS gels, unaltered or marginally increased cytoskeletal association, and its catalytic activity changed in a biphasic manner; during the first 10-20 min of PAO-treatment the activity increased and then it declined to very low values within 1-2 hr. Our data suggest that p56lck contains both positive and negative regulatory sites which are constantly dephosphorylated at an unexpectedly high rate by cellular phosphotyrosine phosphatases.
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Affiliation(s)
- C Oetken
- Division of Cell Biology, La Jolla Institute for Allergy and Immunology, California 92037
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41
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Weil R, Veillette A. Intramolecular and extramolecular mechanisms repress the catalytic function of p56lck in resting T-lymphocytes. J Biol Chem 1994. [DOI: 10.1016/s0021-9258(17)31720-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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42
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Flint NA, Amrein KE, Jascur T, Burn P. Purification and characterization of an activated form of the protein tyrosine kinase Lck from an Escherichia coli expression system. J Cell Biochem 1994; 55:389-97. [PMID: 7962172 DOI: 10.1002/jcb.240550317] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
The lymphocyte-specific, nonreceptor protein tyrosine kinase Lck has been purified from an Escherichia coli expression system using a monoclonal antibody column followed by dye-affinity chromatography. Polyacrylamide gel electrophoretic analysis of purified protein revealed a single 56 kDa band, indicating that recombinant Lck was purified to near-homogeneity. The purified enzyme displayed tyrosine kinase activity as measured by both autophosphorylation and phosphorylation of exogenous substrates. Biochemical properties including protein phosphorylation and kinetic characteristics of the enzyme have been assessed. Peptide map analysis revealed that bacterially expressed Lck is phosphorylated predominantly on the autophosphorylation site (tyrosine-394), which is characteristic for activated protein tyrosine kinases. Indeed, we found that the recombinant enzyme is approximately fivefold more active than Lck from resting T cells, which is extensively phosphorylated at the regulatory carboxy-terminal tyrosine residue (tyrosine-505). Thus, we have overproduced recombinant human Lck in E. coli and developed a simple two-step purification procedure which yields highly active enzyme. This will enable the identification and characterization of potential regulators and targets of Lck and thereby greatly facilitate studies which will clarify its role in T cell signal transduction.
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Affiliation(s)
- N A Flint
- Department of Biology, Pharmaceutical Research-New Technologies, F. Hoffmann-La Roche Ltd., Basel, Switzerland
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