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Kueffer LE, Lin DYW, Amatya N, Serrenho J, Joseph RE, Courtney AH, Andreotti AH. Screening and Characterization of Allosteric Small Molecules Targeting Bruton's Tyrosine Kinase. Biochemistry 2024; 63:94-106. [PMID: 38091504 DOI: 10.1021/acs.biochem.3c00362] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2024]
Abstract
Bruton's Tyrosine Kinase (BTK) is a nonreceptor tyrosine kinase that belongs to the TEC family. Mutations in the BTK gene cause X-linked agammaglobulinemia (XLA) leading to an arrest in B-cell development. BTK is also a drug target for B-cell lymphomas that rely on an intact B-cell receptor signaling cascade for survival. All FDA approved drugs for BTK target the ATP binding site of the catalytic kinase domain, leading to potential adverse events due to off-target inhibition. In addition, acquired resistance mutations occur in a subset of patients, rendering available BTK inhibitors ineffective. Therefore, allosteric sites on BTK should be explored for drug development to target BTK more specifically and in combination with active site inhibitors. Virtual screening against nonactive site pockets and in vitro experiments resulted in a series of small molecules that bind to BTK outside of the active site. We characterized these compounds using biochemical and biophysical techniques and narrowed our focus to compound "C2". C2 activates full-length BTK and smaller multidomain BTK fragments but not the isolated kinase domain, consistent with an allosteric mode of action. Kinetic experiments reveal a C2-mediated decrease in Km and an increase in kcat leading to an overall increase in the catalytic efficiency of BTK. C2 is also capable of activating the BTK XLA mutants. These proof-of-principle data reveal that BTK can be targeted allosterically with small molecules, providing an alternative to active site BTK inhibitors.
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Affiliation(s)
- Lauren E Kueffer
- Roy J. Carver Department of Biochemistry, Biophysics, and Molecular Biology, Iowa State University, Ames, Iowa 50011, United States
| | - David Yin-Wei Lin
- Roy J. Carver Department of Biochemistry, Biophysics, and Molecular Biology, Iowa State University, Ames, Iowa 50011, United States
| | - Neha Amatya
- Roy J. Carver Department of Biochemistry, Biophysics, and Molecular Biology, Iowa State University, Ames, Iowa 50011, United States
| | - Joseph Serrenho
- Department of Pharmacology, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Raji E Joseph
- Roy J. Carver Department of Biochemistry, Biophysics, and Molecular Biology, Iowa State University, Ames, Iowa 50011, United States
| | - Adam H Courtney
- Department of Pharmacology, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Amy H Andreotti
- Roy J. Carver Department of Biochemistry, Biophysics, and Molecular Biology, Iowa State University, Ames, Iowa 50011, United States
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2
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Joseph RE, Wales TE, Jayne S, Britton RG, Fulton DB, Engen JR, Dyer MJS, Andreotti AH. Impact of the clinically approved BTK inhibitors on the conformation of full-length BTK and analysis of the development of BTK resistance mutations in chronic lymphocytic leukemia. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.12.18.572223. [PMID: 38187560 PMCID: PMC10769265 DOI: 10.1101/2023.12.18.572223] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2024]
Abstract
Inhibition of Bruton's tyrosine kinase (BTK) has proven to be highly effective in the treatment of B-cell malignancies such as chronic lymphocytic leukemia (CLL), autoimmune disorders and multiple sclerosis. Since the approval of the first BTK inhibitor (BTKi), Ibrutinib, several other inhibitors including Acalabrutinib, Zanubrutinib, Tirabrutinib and Pirtobrutinib have been clinically approved. All are covalent active site inhibitors, with the exception of the reversible active site inhibitor Pirtobrutinib. The large number of available inhibitors for the BTK target creates challenges in choosing the most appropriate BTKi for treatment. Side-by-side comparisons in CLL have shown that different inhibitors may differ in their treatment efficacy. Moreover, the nature of the resistance mutations that arise in patients appears to depend on the specific BTKi administered. We have previously shown that Ibrutinib binding to the kinase active site causes unanticipated long-range effects on the global conformation of BTK (Joseph, R.E., et al., 2020, https://doi.org/10.7554/eLife.60470 ). Here we show that binding of each of the five approved BTKi to the kinase active site brings about distinct allosteric changes that alter the conformational equilibrium of full-length BTK. Additionally, we provide an explanation for the resistance mutation bias observed in CLL patients treated with different BTKi and characterize the mechanism of action of two common resistance mutations: BTK T474I and L528W.
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3
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Hallumi E, Shalah R, Lo WL, Corso J, Oz I, Beach D, Wittman S, Isenberg A, Sela M, Urlaub H, Weiss A, Yablonski D. Itk Promotes the Integration of TCR and CD28 Costimulation through Its Direct Substrates SLP-76 and Gads. THE JOURNAL OF IMMUNOLOGY 2021; 206:2322-2337. [PMID: 33931484 DOI: 10.4049/jimmunol.2001053] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/16/2020] [Accepted: 03/15/2021] [Indexed: 11/19/2022]
Abstract
The costimulatory receptor CD28 synergizes with the TCR to promote IL-2 production, cell survival, and proliferation; yet the obligatory interdependence of TCR and CD28 signaling is not well understood. Upon TCR stimulation, Gads, a Grb2-family adaptor, bridges the interaction of two additional adaptors, LAT and SLP-76, to form a TCR-induced effector signaling complex. SLP-76 binds the Tec-family tyrosine kinase, Itk, which phosphorylates SLP-76 Y173 and PLC-γ1 Y783. In this study, we identified TCR-inducible, Itk-mediated phosphorylation of Gads Y45 in a human T cell line and in mouse primary T cells. Y45 is found within the N-terminal SH3 domain of Gads, an evolutionarily conserved domain with no known signaling function. Gads Y45 phosphorylation depended on the interaction of Gads with SLP-76 and on the dimerization-dependent binding of Gads to phospho-LAT. We provide evidence that Itk acts through SLP-76 and Gads to promote the TCR/CD28-induced activation of the RE/AP transcriptional element from the IL-2 promoter. Two Itk-related features of SLP-76, Y173 and a proline-rich Itk SH3 binding motif on SLP-76, were dispensable for activation of NFAT but selectively required for the TCR/CD28-induced increase in cytoplasmic and nuclear c-Rel and consequent RE/AP activation. We provide evidence that unphosphorylated, monomeric Gads mediates an RE/AP-directed inhibitory activity that is mitigated upon Gads dimerization and Y45 phosphorylation. This study illuminates a new, to our knowledge, regulatory module, in which TCR-induced, Itk-mediated phosphorylation sites on SLP-76 and Gads control the transcriptional response to TCR/CD28 costimulation, thus enforcing the obligatory interdependence of the TCR and CD28 signaling pathways.
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Affiliation(s)
- Enas Hallumi
- Department of Immunology, Ruth and Bruce Rappaport Faculty of Medicine, Technion - Israel Institute of Technology, Haifa, Israel
| | - Rose Shalah
- Department of Immunology, Ruth and Bruce Rappaport Faculty of Medicine, Technion - Israel Institute of Technology, Haifa, Israel
| | - Wan-Lin Lo
- Rosalind Russell and Ephraim P. Engleman Arthritis Research Center, Division of Rheumatology, Department of Medicine, University of California, San Francisco, San Francisco, CA
| | - Jasmin Corso
- Bioanalytical Mass Spectrometry Group, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
| | - Ilana Oz
- Department of Immunology, Ruth and Bruce Rappaport Faculty of Medicine, Technion - Israel Institute of Technology, Haifa, Israel
| | - Dvora Beach
- Department of Immunology, Ruth and Bruce Rappaport Faculty of Medicine, Technion - Israel Institute of Technology, Haifa, Israel
| | - Samuel Wittman
- Department of Immunology, Ruth and Bruce Rappaport Faculty of Medicine, Technion - Israel Institute of Technology, Haifa, Israel
| | - Amy Isenberg
- Department of Immunology, Ruth and Bruce Rappaport Faculty of Medicine, Technion - Israel Institute of Technology, Haifa, Israel
| | - Meirav Sela
- Department of Immunology, Ruth and Bruce Rappaport Faculty of Medicine, Technion - Israel Institute of Technology, Haifa, Israel
| | - Henning Urlaub
- Bioanalytical Mass Spectrometry Group, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany.,Bioanalytics Research Group, Institute for Clinical Chemistry, University Medical Center Göttingen, Göttingen, Germany
| | - Arthur Weiss
- Rosalind Russell and Ephraim P. Engleman Arthritis Research Center, Division of Rheumatology, Department of Medicine, University of California, San Francisco, San Francisco, CA.,Howard Hughes Medical Institute, University of California, San Francisco, San Francisco, CA
| | - Deborah Yablonski
- Department of Immunology, Ruth and Bruce Rappaport Faculty of Medicine, Technion - Israel Institute of Technology, Haifa, Israel
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4
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Btk SH2-kinase interface is critical for allosteric kinase activation and its targeting inhibits B-cell neoplasms. Nat Commun 2020; 11:2319. [PMID: 32385234 PMCID: PMC7210950 DOI: 10.1038/s41467-020-16128-5] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2020] [Accepted: 04/15/2020] [Indexed: 02/07/2023] Open
Abstract
Bruton’s tyrosine kinase (Btk) is critical for B-cell maturation and activation. Btk loss-of-function mutations cause human X-linked agammaglobulinemia (XLA). In contrast, Btk signaling sustains growth of several B-cell neoplasms which may be treated with tyrosine kinase inhibitors (TKIs). Here, we uncovered the structural mechanism by which certain XLA mutations in the SH2 domain strongly perturb Btk activation. Using a combination of molecular dynamics (MD) simulations and small-angle X-ray scattering (SAXS), we discovered an allosteric interface between the SH2 and kinase domain required for Btk activation and to which multiple XLA mutations map. As allosteric interactions provide unique targeting opportunities, we developed an engineered repebody protein binding to the SH2 domain and able to disrupt the SH2-kinase interaction. The repebody prevents activation of wild-type and TKI-resistant Btk, inhibiting Btk-dependent signaling and proliferation of malignant B-cells. Therefore, the SH2-kinase interface is critical for Btk activation and a targetable site for allosteric inhibition. Constitutive Btk signaling drives several B-cell cancers. Here the authors demonstrate key allosteric intramolecular interactions between the SH2 domain and the kinase domain of Btk, and propose an alternative approach for inhibition of both wild-type and tyrosine kinase inhibitor-resistant Btk.
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Design, synthesis and evaluation of novel 7H-pyrrolo[2,3-d]pyrimidin-4-amine derivatives as potent, selective and reversible Bruton's tyrosine kinase (BTK) inhibitors for the treatment of rheumatoid arthritis. Eur J Med Chem 2019; 169:121-143. [DOI: 10.1016/j.ejmech.2019.02.077] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2019] [Revised: 02/27/2019] [Accepted: 02/28/2019] [Indexed: 01/29/2023]
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6
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Devkota S, Joseph RE, Boyken SE, Fulton DB, Andreotti AH. An Autoinhibitory Role for the Pleckstrin Homology Domain of Interleukin-2-Inducible Tyrosine Kinase and Its Interplay with Canonical Phospholipid Recognition. Biochemistry 2017; 56:2938-2949. [PMID: 28516764 DOI: 10.1021/acs.biochem.6b01182] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Pleckstrin homology (PH) domains are well-known as phospholipid binding modules, yet evidence that PH domain function extends beyond lipid recognition is mounting. In this work, we characterize a protein binding function for the PH domain of interleukin-2-inducible tyrosine kinase (ITK), an immune cell specific signaling protein that belongs to the TEC family of nonreceptor tyrosine kinases. Its N-terminal PH domain is a well-characterized lipid binding module that localizes ITK to the membrane via phosphatidylinositol 3,4,5-trisphosphate (PIP3) binding. Using a combination of nuclear magnetic resonance spectroscopy and mutagenesis, we have mapped an autoregulatory protein interaction site on the ITK PH domain that makes direct contact with the catalytic kinase domain of ITK, inhibiting the phospho-transfer reaction. Moreover, we have elucidated an important interplay between lipid binding by the ITK PH domain and the stability of the autoinhibitory complex formed by full length ITK. The ITK activation loop in the kinase domain becomes accessible to phosphorylation to the exogenous kinase LCK upon binding of the ITK PH domain to PIP3. By clarifying the allosteric role of the ITK PH domain in controlling ITK function, we have expanded the functional repertoire of the PH domain generally and opened the door to alternative strategies to target this specific kinase in the context of immune cell signaling.
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Affiliation(s)
- Sujan Devkota
- Roy J. Carver Department of Biochemistry, Biophysics and Molecular Biology, Iowa State University , Ames, Iowa 50011, United States
| | - Raji E Joseph
- Roy J. Carver Department of Biochemistry, Biophysics and Molecular Biology, Iowa State University , Ames, Iowa 50011, United States
| | - Scott E Boyken
- Roy J. Carver Department of Biochemistry, Biophysics and Molecular Biology, Iowa State University , Ames, Iowa 50011, United States
| | - D Bruce Fulton
- Roy J. Carver Department of Biochemistry, Biophysics and Molecular Biology, Iowa State University , Ames, Iowa 50011, United States
| | - Amy H Andreotti
- Roy J. Carver Department of Biochemistry, Biophysics and Molecular Biology, Iowa State University , Ames, Iowa 50011, United States
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7
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Kim KD, Bae S, Capece T, Nedelkovska H, de Rubio RG, Smrcka AV, Jun CD, Jung W, Park B, Kim TI, Kim M. Targeted calcium influx boosts cytotoxic T lymphocyte function in the tumour microenvironment. Nat Commun 2017; 8:15365. [PMID: 28504276 PMCID: PMC5440668 DOI: 10.1038/ncomms15365] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2016] [Accepted: 03/23/2017] [Indexed: 12/15/2022] Open
Abstract
Adoptive cell transfer utilizing tumour-targeting cytotoxic T lymphocytes (CTLs) is one of the most effective immunotherapies against haematological malignancies, but significant clinical success has not yet been achieved in solid tumours due in part to the strong immunosuppressive tumour microenvironment. Here, we show that suppression of CTL killing by CD4+CD25+Foxp3+ regulatory T cell (Treg) is in part mediated by TGFβ-induced inhibition of inositol trisphosphate (IP3) production, leading to a decrease in T cell receptor (TCR)-dependent intracellular Ca2+ response. Highly selective optical control of Ca2+ signalling in adoptively transferred CTLs enhances T cell activation and IFN-γ production in vitro, leading to a significant reduction in tumour growth in mice. Altogether, our findings indicate that the targeted optogenetic stimulation of intracellular Ca2+ signal allows for the remote control of cytotoxic effector functions of adoptively transferred T cells with outstanding spatial resolution by boosting T cell immune responses at the tumour sites.
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MESH Headings
- Animals
- Calcium/immunology
- Calcium/metabolism
- Cell Line, Tumor
- HEK293 Cells
- Humans
- Immunotherapy, Adoptive/methods
- Interferon-gamma/genetics
- Interferon-gamma/immunology
- Interferon-gamma/metabolism
- Mice, Inbred C57BL
- Mice, Knockout
- Mice, Transgenic
- Neoplasms, Experimental/genetics
- Neoplasms, Experimental/immunology
- Neoplasms, Experimental/therapy
- T-Lymphocytes, Cytotoxic/immunology
- T-Lymphocytes, Cytotoxic/metabolism
- T-Lymphocytes, Cytotoxic/transplantation
- T-Lymphocytes, Regulatory/immunology
- T-Lymphocytes, Regulatory/metabolism
- Tumor Burden/genetics
- Tumor Burden/immunology
- Tumor Microenvironment/genetics
- Tumor Microenvironment/immunology
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Affiliation(s)
- Kyun-Do Kim
- Department of Microbiology and Immunology, David H. Smith Center for Vaccine Biology and Immunology, University of Rochester, Rochester, New York 14642, USA
| | - Seyeon Bae
- Department of Microbiology and Immunology, David H. Smith Center for Vaccine Biology and Immunology, University of Rochester, Rochester, New York 14642, USA
| | - Tara Capece
- Department of Microbiology and Immunology, David H. Smith Center for Vaccine Biology and Immunology, University of Rochester, Rochester, New York 14642, USA
| | - Hristina Nedelkovska
- Department of Microbiology and Immunology, David H. Smith Center for Vaccine Biology and Immunology, University of Rochester, Rochester, New York 14642, USA
| | - Rafael G. de Rubio
- Department of Pharmacology & Physiology, University of Rochester, Rochester, New York 14642, USA
| | - Alan V. Smrcka
- Department of Pharmacology & Physiology, University of Rochester, Rochester, New York 14642, USA
| | - Chang-Duk Jun
- School of Life Sciences, Immune Synapse and Cell Therapy Research Center, Gwangju Institute of Science and Technology, Gwangju 500-712, Republic of Korea
| | - Woojin Jung
- School of Chemical Engineering, Sungkyunkwan University, Suwon, Gyeonggi-do 440-746, Republic of Korea
| | - Byeonghak Park
- School of Chemical Engineering, Sungkyunkwan University, Suwon, Gyeonggi-do 440-746, Republic of Korea
| | - Tae-il Kim
- School of Chemical Engineering, Sungkyunkwan University, Suwon, Gyeonggi-do 440-746, Republic of Korea
| | - Minsoo Kim
- Department of Microbiology and Immunology, David H. Smith Center for Vaccine Biology and Immunology, University of Rochester, Rochester, New York 14642, USA
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8
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Oruganty K, Talevich EE, Neuwald AF, Kannan N. Identification and classification of small molecule kinases: insights into substrate recognition and specificity. BMC Evol Biol 2016; 16:7. [PMID: 26738562 PMCID: PMC4702295 DOI: 10.1186/s12862-015-0576-x] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2015] [Accepted: 12/21/2015] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND Many prokaryotic kinases that phosphorylate small molecule substrates, such as antibiotics, lipids and sugars, are evolutionarily related to Eukaryotic Protein Kinases (EPKs). These Eukaryotic-Like Kinases (ELKs) share the same overall structural fold as EPKs, but differ in their modes of regulation, substrate recognition and specificity-the sequence and structural determinants of which are poorly understood. RESULTS To better understand the basis for ELK specificity, we applied a Bayesian classification procedure designed to identify sequence determinants responsible for functional divergence. This reveals that a large and diverse family of aminoglycoside kinases, characterized members of which are involved in antibiotic resistance, fall into major sub-groups based on differences in putative substrate recognition motifs. Aminoglycoside kinase substrate specificity follows simple rules of alternating hydroxyl and amino groups that is strongly correlated with variations at the DFG + 1 position. CONCLUSIONS Substrate specificity determining features in small molecule kinases are mostly confined to the catalytic core and can be identified based on quantitative sequence and crystal structure comparisons.
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Affiliation(s)
- Krishnadev Oruganty
- Department of Biochemistry & Molecular Biology, University of Georgia, Athens, GA, 30602, USA.
| | - Eric E Talevich
- Department of Pathology and Helen Diller Family Comprehensive Cancer Center, University of California, San Francisco, CA, 94158, USA.
| | - Andrew F Neuwald
- Institute for Genome Sciences and Department of Biochemistry & Molecular Biology, School of Medicine, University of Maryland, Baltimore, MD, 21201, USA.
| | - Natarajan Kannan
- Department of Biochemistry & Molecular Biology, University of Georgia, Athens, GA, 30602, USA.
- Institute of Bioinformatics, University of Georgia, Athens, GA, 30602, USA.
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9
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Devkota S, Joseph RE, Min L, Bruce Fulton D, Andreotti AH. Scaffold Protein SLP-76 Primes PLCγ1 for Activation by ITK-Mediated Phosphorylation. J Mol Biol 2015; 427:2734-47. [PMID: 25916191 DOI: 10.1016/j.jmb.2015.04.012] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2015] [Revised: 04/04/2015] [Accepted: 04/06/2015] [Indexed: 11/25/2022]
Abstract
Activation of the phospholipase, PLCγ1, is critical for proper T cell signaling following antigen receptor engagement. In T cells, the Tec family kinase, interleukin-2-induced tyrosine kinase (ITK), phosphorylates PLCγ1 at tyrosine 783 (Y783) leading to activation of phospholipase function and subsequent production of the second messengers inositol 1,4,5-trisphosphate and diacylglycerol. In this work, we demonstrate that PLCγ1 can be primed for ITK-mediated phosphorylation on Y783 by a specific region of the adaptor protein, SLP-76. The SLP-76 phosphotyrosine-containing sequence, pY(173)IDR, does not conform to the canonical recognition motif for an SH2 domain yet binds with significant affinity to the C-terminal SH2 domain of PLCγ1 (SH2C). The SLP-76 pY(173) motif competes with the autoinhibited conformation surrounding the SH2C domain of PLCγ1 leading to exposure of the ITK recognition element on the PLCγ1 SH2 domain and release of the target tyrosine, Y783. These data contribute to the evolving model for the molecular events occurring early in the T cell activation process.
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Affiliation(s)
- Sujan Devkota
- Roy J. Carver Department of Biochemistry, Biophysics and Molecular Biology, Iowa State University, Ames, IA 50011, USA
| | - Raji E Joseph
- Roy J. Carver Department of Biochemistry, Biophysics and Molecular Biology, Iowa State University, Ames, IA 50011, USA
| | - Lie Min
- Department of Chemical and Biomolecular Engineering, University of Delaware, Newark, DE 19711, USA
| | - D Bruce Fulton
- Roy J. Carver Department of Biochemistry, Biophysics and Molecular Biology, Iowa State University, Ames, IA 50011, USA
| | - Amy H Andreotti
- Roy J. Carver Department of Biochemistry, Biophysics and Molecular Biology, Iowa State University, Ames, IA 50011, USA.
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10
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Huang W, August A. The signaling symphony: T cell receptor tunes cytokine-mediated T cell differentiation. J Leukoc Biol 2015; 97:477-85. [PMID: 25525115 PMCID: PMC4338847 DOI: 10.1189/jlb.1ri0614-293r] [Citation(s) in RCA: 56] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2014] [Revised: 11/03/2014] [Accepted: 11/13/2014] [Indexed: 01/07/2023] Open
Abstract
T cell development, differentiation, and maintenance are orchestrated by 2 key signaling axes: the antigen-specific TCR and cytokine-mediated signals. The TCR signals the recognition of self- and foreign antigens to control T cell homeostasis for immune tolerance and immunity, which is regulated by a variety of cytokines to determine T cell subset homeostasis and differentiation. TCR signaling can synergize with or antagonize cytokine-mediated signaling to fine tune T cell fate; however, the latter is less investigated. Murine models with attenuated TCR signaling strength have revealed that TCR signaling can function as regulatory feedback machinery for T cell homeostasis and differentiation in differential cytokine milieus, such as IL-2-mediated Treg development; IL-7-mediated, naïve CD8(+) T cell homeostasis; and IL-4-induced innate memory CD8(+) T cell development. In this review, we discuss the symphonic cross-talk between TCR and cytokine-mediated responses that differentially control T cell behavior, with a focus on the negative tuning by TCR activation on the cytokine effects.
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Affiliation(s)
- Weishan Huang
- Department of Microbiology and Immunology, Cornell University, Ithaca, New York, USA
| | - Avery August
- Department of Microbiology and Immunology, Cornell University, Ithaca, New York, USA
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11
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Modulation of TCR responsiveness by the Grb2-family adaptor, Gads. Cell Signal 2014; 27:125-34. [PMID: 25452106 DOI: 10.1016/j.cellsig.2014.10.005] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2014] [Accepted: 10/16/2014] [Indexed: 12/11/2022]
Abstract
T cell antigen receptor (TCR) signaling depends on three interacting adaptor proteins: SLP-76, Gads, and LAT. Their mechanisms of signaling have been extensively explored, with the aid of fortuitously isolated LAT- and SLP-76-deficient T cell lines, but no such tools were available for Gads, a Grb2-family adaptor that bridges the TCR-inducible interaction between SLP-76 and LAT. TALEN-directed genome editing was applied to disrupt the first coding exon of human Gads in the Jurkat T cell line. Gads was dispensable for TCR-induced phosphorylation of SLP-76, but was a dose-dependent amplifier of TCR-induced CD69 expression. Gads conferred responsiveness to weak TCR stimuli, leading to PLC-γ1 phosphorylation and calcium flux. TALEN-derived, Gads-deficient T cell lines provide a uniquely tractable genetic platform for exploring its regulatory features, such as Gads phosphorylation at T262, which we observed by mass spectrometry. Upon mutation of this site, TCR responsiveness and sensitivity to weak TCR stimuli were increased. This study demonstrates the feasibility of TALEN-based reverse genetics in Jurkat T cells, while enriching our understanding of Gads as a regulated modulator of TCR sensitivity.
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12
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Boyken SE, Chopra N, Xie Q, Joseph RE, Wales TE, Fulton DB, Engen JR, Jernigan RL, Andreotti AH. A conserved isoleucine maintains the inactive state of Bruton's tyrosine kinase. J Mol Biol 2014; 426:3656-69. [PMID: 25193673 DOI: 10.1016/j.jmb.2014.08.018] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2014] [Revised: 08/22/2014] [Accepted: 08/23/2014] [Indexed: 12/22/2022]
Abstract
Despite high level of homology among non-receptor tyrosine kinases, different kinase families employ a diverse array of regulatory mechanisms. For example, the catalytic kinase domains of the Tec family kinases are inactive without assembly of the adjacent regulatory domains, whereas the Src kinase domains are autoinhibited by the assembly of similar adjacent regulatory domains. Using molecular dynamics simulations, biochemical assays, and biophysical approaches, we have uncovered an isoleucine residue in the kinase domain of the Tec family member Btk that, when mutated to the closely related leucine, leads to a shift in the conformational equilibrium of the kinase domain toward the active state. The single amino acid mutation results in measureable catalytic activity for the Btk kinase domain in the absence of the regulatory domains. We suggest that this isoleucine side chain in the Tec family kinases acts as a "wedge" that restricts the conformational space available to key regions in the kinase domain, preventing activation until the kinase domain associates with its regulatory subunits and overcomes the energetic barrier to activation imposed by the isoleucine side chain.
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Affiliation(s)
- Scott E Boyken
- Roy J. Carver Department of Biochemistry, Biophysics and Molecular Biology, Iowa State University, Ames, IA 50011, USA
| | - Nikita Chopra
- Roy J. Carver Department of Biochemistry, Biophysics and Molecular Biology, Iowa State University, Ames, IA 50011, USA
| | - Qian Xie
- Roy J. Carver Department of Biochemistry, Biophysics and Molecular Biology, Iowa State University, Ames, IA 50011, USA
| | - Raji E Joseph
- Roy J. Carver Department of Biochemistry, Biophysics and Molecular Biology, Iowa State University, Ames, IA 50011, USA
| | - Thomas E Wales
- Department of Chemistry and Chemical Biology, Northeastern University, Boston, MA 02115, USA
| | - D Bruce Fulton
- Roy J. Carver Department of Biochemistry, Biophysics and Molecular Biology, Iowa State University, Ames, IA 50011, USA
| | - John R Engen
- Department of Chemistry and Chemical Biology, Northeastern University, Boston, MA 02115, USA
| | - Robert L Jernigan
- Roy J. Carver Department of Biochemistry, Biophysics and Molecular Biology, Iowa State University, Ames, IA 50011, USA
| | - Amy H Andreotti
- Roy J. Carver Department of Biochemistry, Biophysics and Molecular Biology, Iowa State University, Ames, IA 50011, USA.
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13
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López-Herrera G, Vargas-Hernández A, González-Serrano ME, Berrón-Ruiz L, Rodríguez-Alba JC, Espinosa-Rosales F, Santos-Argumedo L. Bruton's tyrosine kinase--an integral protein of B cell development that also has an essential role in the innate immune system. J Leukoc Biol 2013; 95:243-50. [PMID: 24249742 DOI: 10.1189/jlb.0513307] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Btk is the protein affected in XLA, a disease identified as a B cell differentiation defect. Btk is crucial for B cell differentiation and activation, but its role in other cells is not fully understood. This review focuses on the function of Btk in monocytes, neutrophils, and platelets and the receptors and signaling cascades in such cells with which Btk is associated.
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Affiliation(s)
- Gabriela López-Herrera
- 1.Col. Insurgentes Cuicuilco, Torre de Investigación 9o. piso, Mexico, D.F., Mexico 04530.
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14
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Joseph RE, Kleino I, Wales TE, Xie Q, Fulton DB, Engen JR, Berg LJ, Andreotti AH. Activation loop dynamics determine the different catalytic efficiencies of B cell- and T cell-specific tec kinases. Sci Signal 2013; 6:ra76. [PMID: 23982207 DOI: 10.1126/scisignal.2004298] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Itk (interleukin-2-inducible T cell kinase) and Btk (Bruton's tyrosine kinase) are nonreceptor tyrosine kinases of the Tec family that signal downstream of the T cell receptor (TCR) and B cell receptor (BCR), respectively. Despite their high sequence similarity and related signaling roles, Btk is a substantially more active kinase than Itk. We showed that substitution of 6 of the 619 amino acid residues of Itk with the corresponding residues of Btk (and vice versa) was sufficient to completely switch the activities of Itk and Btk. The substitutions responsible for the swap in activity are all localized to the activation segment of the kinase domain. Nuclear magnetic resonance and hydrogen-deuterium exchange mass spectrometry analyses revealed that Itk and Btk had distinct protein dynamics in this region, which could explain the differences in catalytic efficiency between these kinases. Introducing Itk with enhanced activity into T cells led to enhanced and prolonged TCR signaling compared to that in cells with wild-type Itk. These findings imply that evolutionary pressures have led to Tec kinases having distinct enzymatic properties, depending on the cellular context. We suggest that the weaker catalytic activities of T cell-specific kinases serve to regulate cellular activation and prevent aberrant immune responses.
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Affiliation(s)
- Raji E Joseph
- Roy J Carver Department of Biochemistry, Biophysics and Molecular Biology, Iowa State University, Ames, IA 50011, USA
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15
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Xie Q, Joseph RE, Fulton DB, Andreotti AH. Substrate recognition of PLCγ1 via a specific docking surface on Itk. J Mol Biol 2012; 425:683-96. [PMID: 23219468 DOI: 10.1016/j.jmb.2012.10.023] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2012] [Revised: 10/29/2012] [Accepted: 10/31/2012] [Indexed: 12/15/2022]
Abstract
Itk (interleukin-2 inducible T cell kinase) is a non-receptor protein tyrosine kinase expressed primarily in T cells. Itk catalyzes phosphorylation on tyrosine residues within a number of its natural substrates, including the well-characterized Y783 of PLCγ1. However, the molecular mechanisms Itk exploits to recognize its substrates are not completely understood. We have previously identified a specific docking interaction between the kinase domain of Itk and the C-terminal Src homology 2 (SH2C) domain of PLCγ1 that promotes substrate specificity for this enzyme/substrate pair. In the current study, we identify and map the interaction surface on the Itk kinase domain as an acidic patch centered on the G helix. Mutation of the residues on and adjacent to the G helix within the Itk kinase domain impairs the catalytic efficacy of PLCγ1 substrate phosphorylation by specifically altering the protein-protein interaction interface and not the inherent catalytic activity of Itk. NMR titration experiments using a Btk (Bruton's tyrosine kinase) kinase domain as a surrogate for the Itk kinase domain provide further support for an Itk/PLCγ1 SH2C interaction surrounding the G helix of the kinase domain. The work presented here provides structural insight into how the Itk kinase uses the G helix to single out Y783 of PLCγ1 for specific phosphorylation. Comparing these results to other well-characterized kinase/substrate systems suggests that the G helix is a general structural feature used by kinases for substrate recognition during signaling.
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Affiliation(s)
- Qian Xie
- Roy J. Carver Department of Biochemistry, Biophysics and Molecular Biology, Iowa State University, Ames, IA 50011, USA
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16
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Hey F, Czyzewicz N, Jones P, Sablitzky F. DEF6, a novel substrate for the Tec kinase ITK, contains a glutamine-rich aggregation-prone region and forms cytoplasmic granules that co-localize with P-bodies. J Biol Chem 2012; 287:31073-84. [PMID: 22829599 DOI: 10.1074/jbc.m112.346767] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Localization of DEF6 (SLAT/IBP), a Rho-family guanine nucleotide exchange factor, to the center of the immune synapse is dependent upon ITK, a Tec-family kinase that regulates the spatiotemporal organization of components of T cell signaling pathways and Cdc42-dependent actin polymerization. Here we demonstrate that ITK both interacts with DEF6 and phosphorylates DEF6 at tyrosine residues Tyr(210) and Tyr(222). Expression of a GFP-tagged Y210E-Y222E phosphomimic resulted in the formation of DEF6 cytoplasmic granules that co-localized with decapping enzyme 1 (DCP1), a marker of P-bodies; sites of mRNA degradation. Similarly treatment of cells with puromycin or sodium arsenite, reagents that arrest translation, also resulted in the accumulation of DEF6 in cytoplasmic granules. Bioinformatics analysis identified a glutamine-rich, heptad-repeat region; a feature of aggregating proteins, within the C-terminal region of DEF6 with the potential to promote granule formation through a phosphorylation-dependent unmasking of this region. These data suggest that in addition to its role as a GEF, DEF6 may also function in regulating mRNA translation.
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Affiliation(s)
- Fiona Hey
- School of Biology, Molecular Cell and Developmental Biology, The University of Nottingham, Nottingham NG7 2UH, United Kingdom
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17
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Boyken SE, Fulton DB, Andreotti AH. Rescue of the aggregation prone Itk Pleckstrin Homology domain by two mutations derived from the related kinases, Btk and Tec. Protein Sci 2012; 21:1288-97. [PMID: 22761113 DOI: 10.1002/pro.2114] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2012] [Revised: 06/19/2012] [Accepted: 06/20/2012] [Indexed: 12/18/2022]
Abstract
IL-2 inducible T-cell kinase (Itk) is a Tec family non-receptor tyrosine kinase involved in signaling downstream of the T-cell receptor. Itk contains an amino-terminal Pleckstrin Homology (PH) domain that binds phosphatidylinositol (3,4,5)-trisphosphate, recruiting Itk to the plasma membrane upon T-cell receptor activation. In addition to phosphoinositide binding, accumulating data suggest that the Itk PH domain likely mediates additional interactions outside of the phosphoinositide ligand binding pocket. The structural basis for additional PH domain functions remains elusive because of the poor recombinant expression and in vitro solution behavior of the Itk PH domain. Here, we determine that the lone α-helix in the Itk PH domain is responsible for the poor solution properties and that mutation of just two residues in the Itk α-helix to the corresponding amino acids in Btk or Tec dramatically improves the soluble recombinant expression and solution behavior of the Itk PH domain. We present this double mutant as a valuable tool to characterize the structure and function of the Itk PH domain. It is also interesting to note that the precise sites of mutation identified in this study appear as somatic mutations associated with cancerous tissue. Collectively, the findings suggest that the two helical residues in the Itk PH domain may serve an important and unique structural role in wild-type Itk that differentiates this tyrosine kinase from its related family members.
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Affiliation(s)
- Scott E Boyken
- Roy J. Carver Department of Biochemistry, Biophysics and Molecular Biology, Iowa State University, Ames, Iowa, USA
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18
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Boucheron N, Ellmeier W. The Role of Tec Family Kinases in the Regulation of T-helper-cell Differentiation. Int Rev Immunol 2012; 31:133-54. [DOI: 10.3109/08830185.2012.664798] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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19
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Targeting the SH2-kinase interface in Bcr-Abl inhibits leukemogenesis. Cell 2011; 147:306-19. [PMID: 22000011 PMCID: PMC3202669 DOI: 10.1016/j.cell.2011.08.046] [Citation(s) in RCA: 111] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2010] [Revised: 06/07/2011] [Accepted: 08/31/2011] [Indexed: 12/02/2022]
Abstract
Chronic myelogenous leukemia (CML) is caused by the constitutively active tyrosine kinase Bcr-Abl and treated with the tyrosine kinase inhibitor (TKI) imatinib. However, emerging TKI resistance prevents complete cure. Therefore, alternative strategies targeting regulatory modules of Bcr-Abl in addition to the kinase active site are strongly desirable. Here, we show that an intramolecular interaction between the SH2 and kinase domains in Bcr-Abl is both necessary and sufficient for high catalytic activity of the enzyme. Disruption of this interface led to inhibition of downstream events critical for CML signaling and, importantly, completely abolished leukemia formation in mice. Furthermore, disruption of the SH2-kinase interface increased sensitivity of imatinib-resistant Bcr-Abl mutants to TKI inhibition. An engineered Abl SH2-binding fibronectin type III monobody inhibited Bcr-Abl kinase activity both in vitro and in primary CML cells, where it induced apoptosis. This work validates the SH2-kinase interface as an allosteric target for therapeutic intervention. PaperFlick
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20
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Schwartz PA, Murray BW. Protein kinase biochemistry and drug discovery. Bioorg Chem 2011; 39:192-210. [PMID: 21872901 DOI: 10.1016/j.bioorg.2011.07.004] [Citation(s) in RCA: 101] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2011] [Accepted: 07/22/2011] [Indexed: 12/19/2022]
Abstract
Protein kinases are fascinating biological catalysts with a rapidly expanding knowledge base, a growing appreciation in cell regulatory control, and an ascendant role in successful therapeutic intervention. To better understand protein kinases, the molecular underpinnings of phosphoryl group transfer, protein phosphorylation, and inhibitor interactions are examined. This analysis begins with a survey of phosphate group and phosphoprotein properties which provide context to the evolutionary selection of phosphorylation as a central mechanism for biological regulation of most cellular processes. Next, the kinetic and catalytic mechanisms of protein kinases are examined with respect to model aqueous systems to define the elements of catalysis. A brief structural biology overview further delves into the molecular basis of catalysis and regulation of catalytic activity. Concomitant with a prominent role in normal physiology, protein kinases have important roles in the disease state. To facilitate effective kinase drug discovery, classic and emerging approaches for characterizing kinase inhibitors are evaluated including biochemical assay design, inhibitor mechanism of action analysis, and proper kinetic treatment of irreversible inhibitors. As the resulting protein kinase inhibitors can modulate intended and unintended targets, profiling methods are discussed which can illuminate a more complete range of an inhibitor's biological activities to enable more meaningful cellular studies and more effective clinical studies. Taken as a whole, a wealth of protein kinase biochemistry knowledge is available, yet it is clear that a substantial extent of our understanding in this field remains to be discovered which should yield many new opportunities for therapeutic intervention.
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Affiliation(s)
- Phillip A Schwartz
- Pfizer Worldwide Research and Development, La Jolla, Pfizer Inc., San Diego, CA 92121, United States
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21
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Sequential phosphorylation of SLP-76 at tyrosine 173 is required for activation of T and mast cells. EMBO J 2011; 30:3160-72. [PMID: 21725281 DOI: 10.1038/emboj.2011.213] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2011] [Accepted: 06/03/2011] [Indexed: 02/03/2023] Open
Abstract
Cooperatively assembled signalling complexes, nucleated by adaptor proteins, integrate information from surface receptors to determine cellular outcomes. In T and mast cells, antigen receptor signalling is nucleated by three adaptors: SLP-76, Gads and LAT. Three well-characterized SLP-76 tyrosine phosphorylation sites recruit key components, including a Tec-family tyrosine kinase, Itk. We identified a fourth, evolutionarily conserved SLP-76 phosphorylation site, Y173, which was phosphorylated upon T-cell receptor stimulation in primary murine and Jurkat T cells. Y173 was required for antigen receptor-induced phosphorylation of phospholipase C-γ1 (PLC-γ1) in both T and mast cells, and for consequent downstream events, including activation of the IL-2 promoter in T cells, and degranulation and IL-6 production in mast cells. In intact cells, Y173 phosphorylation depended on three, ZAP-70-targeted tyrosines at the N-terminus of SLP-76 that recruit and activate Itk, a kinase that selectively phosphorylated Y173 in vitro. These data suggest a sequential mechanism whereby ZAP-70-dependent priming of SLP-76 at three N-terminal sites triggers reciprocal regulatory interactions between Itk and SLP-76, which are ultimately required to couple active Itk to its substrate, PLC-γ1.
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22
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Qi Q, Kannan AK, August A. Structure and function of Tec family kinase Itk. Biomol Concepts 2011; 2:223-32. [PMID: 25962031 DOI: 10.1515/bmc.2011.020] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2011] [Accepted: 05/11/2011] [Indexed: 11/15/2022] Open
Abstract
Itk is a member of the Tec family of kinases that is expressed predominantly in T cells. Itk regulates the T cell receptor signaling pathway to modulate T cell development and T helper cell differentiation, particularly Th2 differentiation. Itk is also important for the development and function of iNKT cells. In this review we discuss current progress on our understanding of the structure, activation and signaling pathway of Itk, in addition to inhibitors that have been developed, which target this kinase. We also place in context the function of Itk, available inhibitors and potential use in treating disease.
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23
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Abstract
Second messenger molecules relay, amplify, and diversify cell surface receptor signals. Two important examples are phosphorylated D-myo-inositol derivatives, such as phosphoinositide lipids within cellular membranes, and soluble inositol phosphates. Here, we review how phosphoinositide metabolism generates multiple second messengers with important roles in T-cell development and function. They include soluble inositol(1,4,5)trisphosphate, long known for its Ca(2+)-mobilizing function, and phosphatidylinositol(3,4,5)trisphosphate, whose generation by phosphoinositide 3-kinase and turnover by the phosphatases PTEN and SHIP control a key "hub" of TCR signaling. More recent studies unveiled important second messenger functions for diacylglycerol, phosphatidic acid, and soluble inositol(1,3,4,5)tetrakisphosphate (IP(4)) in immune cells. Inositol(1,3,4,5)tetrakisphosphate acts as a soluble phosphatidylinositol(3,4,5)trisphosphate analog to control protein membrane recruitment. We propose that phosphoinositide lipids and soluble inositol phosphates (IPs) can act as complementary partners whose interplay could have broadly important roles in cellular signaling.
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Affiliation(s)
- Yina H Huang
- Department of Pathology, Washington University School of Medicine, St. Louis, Missouri 63110, USA
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24
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Joseph RE, Xie Q, Andreotti AH. Identification of an allosteric signaling network within Tec family kinases. J Mol Biol 2010; 403:231-42. [PMID: 20826165 DOI: 10.1016/j.jmb.2010.08.035] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2010] [Revised: 08/13/2010] [Accepted: 08/17/2010] [Indexed: 01/20/2023]
Abstract
The Tec family kinases are tyrosine kinases that function primarily in hematopoietic cells. The catalytic activity of the Tec kinases is positively influenced by the regulatory domains outside of the kinase domain. The current lack of a full-length Tec kinase structure leaves a void in our understanding of how these positive regulatory signals are transmitted to the kinase domain. Recently, a conserved structure within kinases, the 'regulatory spine', which assembles and disassembles as a kinase switches between its active and inactive states, has been identified. Here, we define the residues that comprise the regulatory spine within Tec kinases. Compared to previously characterized systems, the Tec kinases contain an extended regulatory spine that includes a conserved methionine within the C-helix and a conserved tryptophan within the Src homology 2-kinase linker of Tec kinases. This extended regulatory spine forms a conduit for transmitting the presence of the regulatory domains of Tec kinases to the catalytic domain. We further show that mutation of the gatekeeper residue at the edge of the regulatory spine stabilizes the regulatory spine, resulting in a constitutively active kinase domain. Importantly, the regulatory spine is preassembled in this gatekeeper mutant, rendering phosphorylation on the activation loop unnecessary for its activity. Moreover, we show that the disruption of the conserved electrostatic interaction between Bruton's tyrosine kinase R544 on the activation loop and Bruton's tyrosine kinase E445 on the C-helix also aids in the assembly of the regulatory spine. Thus, the extended regulatory spine is a key structure that is critical for maintaining the activity of Tec kinases.
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Affiliation(s)
- Raji E Joseph
- Department of Biochemistry, Biophysics and Molecular Biology, Iowa State University, Ames, IA 50011, USA
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25
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Andreotti AH, Schwartzberg PL, Joseph RE, Berg LJ. T-cell signaling regulated by the Tec family kinase, Itk. Cold Spring Harb Perspect Biol 2010; 2:a002287. [PMID: 20519342 DOI: 10.1101/cshperspect.a002287] [Citation(s) in RCA: 171] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
The Tec family tyrosine kinases regulate lymphocyte development, activation, and differentiation. In T cells, the predominant Tec kinase is Itk, which functions downstream of the T-cell receptor to regulate phospholipase C-gamma. This review highlights recent advances in our understanding of Itk kinase structure and enzymatic regulation, focusing on Itk protein domain interactions and mechanisms of substrate recognition. We also discuss the role of Itk in the development of conventional versus innate T-cell lineages, including both alphabeta and gammadelta T-cell subsets. Finally, we describe the complex role of Itk signaling in effector T-cell differentiation and the regulation of cytokine gene expression. Together, these data implicate Itk as an important modulator of T-cell signaling and function.
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Affiliation(s)
- Amy H Andreotti
- Department of Biochemistry, Biophysics and Molecular Biology, Iowa State University, Ames, Iowa 50011, USA.
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26
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The Src, Syk, and Tec family kinases: distinct types of molecular switches. Cell Signal 2010; 22:1175-84. [PMID: 20206686 DOI: 10.1016/j.cellsig.2010.03.001] [Citation(s) in RCA: 184] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2010] [Accepted: 03/01/2010] [Indexed: 01/03/2023]
Abstract
The Src, Syk, and Tec family kinases are three of the most well characterized tyrosine kinase families found in the human genome. Members of these kinase families function downstream of antigen and F(c) receptors in hematopoietic cells and transduce signals leading to calcium mobilization, altered gene expression, cytokine production, and cell proliferation. Over the last several years, structural and biochemical studies have begun to uncover the molecular mechanisms regulating activation of these kinases. It appears that each kinase family functions as a distinct type of molecular switch. This review discusses the activation of the Src, Syk, and Tec kinases from the perspective of structure, phosphorylation, allosteric regulation, and kinetics. The multiple factors that regulate the Src, Syk, and Tec families illustrate the important role played by each of these kinases in immune cell signaling.
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27
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Itk tyrosine kinase substrate docking is mediated by a nonclassical SH2 domain surface of PLCgamma1. Proc Natl Acad Sci U S A 2009; 106:21143-8. [PMID: 19955438 DOI: 10.1073/pnas.0911309106] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Interleukin-2 tyrosine kinase (Itk) is a Tec family tyrosine kinase that mediates signaling processes after T cell receptor engagement. Activation of Itk requires recruitment to the membrane via its pleckstrin homology domain, phosphorylation of Itk by the Src kinase, Lck, and binding of Itk to the SLP-76/LAT adapter complex. After activation, Itk phosphorylates and activates phospholipase C-gamma1 (PLC-gamma1), leading to production of two second messengers, DAG and IP(3). We have previously shown that phosphorylation of PLC-gamma1 by Itk requires a direct, phosphotyrosine-independent interaction between the Src homology 2 (SH2) domain of PLC-gamma1 and the kinase domain of Itk. We now define this docking interface using a combination of mutagenesis and NMR spectroscopy and show that disruption of the Itk/PLCgamma1 docking interaction attenuates T cell signaling. The binding surface on PLCgamma1 that mediates recognition by Itk highlights a nonclassical binding activity of the well-studied SH2 domain providing further evidence that SH2 domains participate in important signaling interactions beyond recognition of phosphotyrosine.
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28
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Joseph RE, Severin A, Min L, Fulton DB, Andreotti AH. SH2-dependent autophosphorylation within the Tec family kinase Itk. J Mol Biol 2009; 391:164-77. [PMID: 19523959 DOI: 10.1016/j.jmb.2009.06.023] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2009] [Revised: 06/03/2009] [Accepted: 06/07/2009] [Indexed: 01/13/2023]
Abstract
The Tec family kinase, Itk (interleukin-2 tyrosine kinase), undergoes an in cis autophosphorylation on Y180 within its Src homology 3 (SH3) domain. Autophosphorylation of the Itk SH3 domain by the Itk kinase domain is strictly dependent on the presence of the intervening Src homology 2 (SH2) domain. A direct docking interaction between the Itk kinase and SH2 domains brings the Itk SH3 domain into the active site where Y180 is then phosphorylated. We now identify the residues on the surface of the Itk SH2 domain responsible for substrate docking and show that this SH2 surface mediates autophosphorylation in the full-length Itk molecule. The canonical phospholigand binding site on the SH2 domain is not involved in substrate docking, instead the docking site consists of side chains from three loop regions (AB, EF and BG) and part of the betaD strand. These results are extended into Btk (Bruton's tyrosine kinase), a Tec family kinase linked to the B-cell deficiency X-linked agammaglobulinemia (XLA). Our results suggest that some XLA-causing mutations might impair Btk phosphorylation.
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Affiliation(s)
- Raji E Joseph
- Department of Biochemistry, Biophysics and Molecular Biology, Iowa State University, Ames, IA 50011, USA
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29
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Abstract
The control of cellular signaling cascades is of utmost importance in regulating the immune response. Exquisitely precise protein-protein interactions and chemical modification of substrates by enzymatic catalysis are the fundamental components of the signals that alert immune cells to the presence of a foreign antigen. In particular, the phosphorylation events induced by protein kinase activity must be spatially and temporally regulated by specific interactions to maintain a normal and effective immune response. High resolution structures of many protein kinases along with supporting biochemical data are providing significant insight into the intricate regulatory mechanisms responsible for controlling cellular signaling. The Tec family kinases are immunologically important kinases for which regulatory details are beginning to emerge. This review focuses on bringing together structural insights gained over the years to develop an understanding of how domain interactions both within the Tec kinases and between the Tec kinases and other signaling molecules control immune cell function.
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Affiliation(s)
- Raji E Joseph
- Department of Biochemistry, Biophysics and Molecular Biology, Iowa State University, Ames, IA 50010, USA
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30
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Severin A, Joseph RE, Boyken S, Fulton DB, Andreotti AH. Proline isomerization preorganizes the Itk SH2 domain for binding to the Itk SH3 domain. J Mol Biol 2009; 387:726-43. [PMID: 19361414 PMCID: PMC2810249 DOI: 10.1016/j.jmb.2009.02.012] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2008] [Revised: 02/06/2009] [Accepted: 02/06/2009] [Indexed: 01/17/2023]
Abstract
We report here the NMR-derived structure of the binary complex formed by the interleukin-2 tyrosine kinase (Itk) Src homology 3 (SH3) and Src homology 2 (SH2) domains. The interaction is independent of both a phosphotyrosine motif and a proline-rich sequence, the classical targets of the SH2 and SH3 domains, respectively. The Itk SH3/SH2 structure reveals the molecular details of this nonclassical interaction and provides a clear picture for how the previously described prolyl cis/trans isomerization present in the Itk SH2 domain mediates SH3 binding. The higher-affinity cis SH2 conformer is preorganized to form a hydrophobic interface with the SH3 domain. The structure also provides insight into how autophosphorylation in the Itk SH3 domain might increase the affinity of the intermolecular SH3/SH2 interaction. Finally, we can compare this Itk complex with other examples of SH3 and SH2 domains engaging their ligands in a nonclassical manner. These small binding domains exhibit a surprising level of diversity in their binding repertoires.
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Affiliation(s)
- Andrew Severin
- Department of Biochemistry, Biophysics, and Molecular Biology, Iowa State University, Ames, IA 50010
| | - Raji E. Joseph
- Department of Biochemistry, Biophysics, and Molecular Biology, Iowa State University, Ames, IA 50010
| | - Scott Boyken
- Department of Biochemistry, Biophysics, and Molecular Biology, Iowa State University, Ames, IA 50010
| | - D. Bruce Fulton
- Department of Biochemistry, Biophysics, and Molecular Biology, Iowa State University, Ames, IA 50010
| | - Amy H. Andreotti
- Department of Biochemistry, Biophysics, and Molecular Biology, Iowa State University, Ames, IA 50010
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31
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Joseph RE, Andreotti AH. Bacterial expression and purification of interleukin-2 tyrosine kinase: single step separation of the chaperonin impurity. Protein Expr Purif 2008; 60:194-7. [PMID: 18495488 DOI: 10.1016/j.pep.2008.04.001] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2008] [Revised: 03/28/2008] [Accepted: 04/03/2008] [Indexed: 11/16/2022]
Abstract
Biochemical and biophysical characterization of kinases requires large quantities of purified protein. Here, we report the bacterial expression and purification of active Itk kinase domain (a Tec family kinase) using ArcticExpress cells that co-express the chaperonin system Cpn60/10 from Oleispira antarctica. We describe a simple one step MgCl2/ATP/KCl incubation procedure to remove the co-purifying chaperonin impurity. Chaperonin co-purification is a common problem encountered during protein purification and the simple incubation step described here completely overcomes this problem. The approach targets the chaperonin system rather than the protein of interest and is therefore widely applicable to other protein targets.
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Affiliation(s)
- Raji E Joseph
- Department of Biochemistry, Biophysics and Molecular Biology, Iowa State University, 4208 MBB, Ames, IA 50011, USA
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32
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Phylogeny of Tec Family Kinases: Identification of a Premetazoan Origin of Btk, Bmx, Itk, Tec, Txk, and the Btk Regulator SH3BP5. ADVANCES IN GENETICS 2008; 64:51-80. [DOI: 10.1016/s0065-2660(08)00803-1] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
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33
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Joseph RE, Fulton DB, Andreotti AH. Mechanism and functional significance of Itk autophosphorylation. J Mol Biol 2007; 373:1281-92. [PMID: 17897671 PMCID: PMC2753204 DOI: 10.1016/j.jmb.2007.08.060] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2007] [Revised: 08/16/2007] [Accepted: 08/28/2007] [Indexed: 12/11/2022]
Abstract
Tec family non-receptor tyrosine kinases (Itk, Btk, Tec, Rlk and Bmx) are characterized by the presence of an autophosphorylation site within the non-catalytic Src homology 3 (SH3) domain. The full-length Itk mutant containing phenylalanine in place of the autophosphorylated tyrosine has been studied in Itk-deficient primary T cells. These studies revealed that the non-phosphorylated enzyme restores Itk mediated signaling only partially. In spite of these insights, the precise role of the Tec kinase autophosphorylation site is unclear and the mechanism of the autophosphorylation reaction within the Tec kinases is not known. Here, we show both in vitro and in vivo that Itk autophosphorylation on Y180 within the SH3 domain occurs exclusively via an intramolecular, in cis mechanism. Using an in vitro kinase assay, we show that mutation of the Itk autophosphorylation site Y180 to Phe decreases kinase activity of the full-length enzyme by increasing Km for a peptide substrate. Moreover, mutation of Y180 to Glu, a residue chosen to mimic the phosphorylated tyrosine, alters the ligand-binding capability of the Itk SH3 domain in a ligand-dependent fashion. NMR chemical shift mapping gives residue-specific structural insight into the effect of the Y180E mutation on ligand binding. These data provide a molecular level context with which to interpret in vivo functional data and allow development of a structural model for Itk autophosphorylation.
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Affiliation(s)
| | | | - Amy H. Andreotti
- To whom correspondence should be addressed: Department of Biochemistry, Biophysics and Molecular Biology, Iowa State University, Ames, IA 50011; Tel.: 515-294-4953; Fax: 515-294-0453; E-mail:
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