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Chowdhury S, Chakraborty MP, Roy S, Dey BP, Gangopadhyay K, Das R. E41K mutation activates Bruton's tyrosine kinase by stabilizing an inositol hexakisphosphate-dependent invisible dimer. J Biol Chem 2024; 300:107535. [PMID: 38971313 PMCID: PMC11338949 DOI: 10.1016/j.jbc.2024.107535] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2024] [Revised: 06/19/2024] [Accepted: 06/21/2024] [Indexed: 07/08/2024] Open
Abstract
Bruton's tyrosine kinase (BTK) regulates diverse cellular signaling of the innate and adaptive immune system in response to microbial pathogens. Downregulation or constitutive activation of BTK is reported in patients with autoimmune diseases or various B-cell leukemias. BTK is a multidomain protein tyrosine kinase that adopts an Src-like autoinhibited conformation maintained by the interaction between the kinase and PH-TH domains. The PH-TH domain plays a central role in regulating BTK function. BTK is activated by binding to PIP3 at the plasma membrane upon stimulation by the B-cell receptor (BCR). The PIP3 binding allows dimerization of the PH-TH domain and subsequent transphosphorylation of the activation loop. Alternatively, a recent study shows that the multivalent T-cell-independent (TI) antigen induces BCR response by activating BTK independent of PIP3 binding. It was proposed that a transiently stable IP6-dependent PH-TH dimer may activate BTK during BCR activation by the TI antigens. However, no IP6-dependent PH-TH dimer has been identified yet. Here, we investigated a constitutively active PH-TH mutant (E41K) to determine if the elusive IP6-dependent PH-TH dimer exists. We showed that the constitutively active E41K mutation activates BTK by stabilizing the IP6-dependent PH-TH dimer. We observed that a downregulating mutation in the PH-TH domain (R28H) linked to X-linked agammaglobulinemia impairs BTK activation at the membrane and in the cytosol by preventing PH-TH dimerization. We conclude that the IP6 dynamically remodels the BTK active fraction between the membrane and the cytoplasm. Stimulating with IP6 increases the cytosolic fraction of the activated BTK.
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Affiliation(s)
- Subhankar Chowdhury
- Department of Biological Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur, India
| | - Manas Pratim Chakraborty
- Department of Biological Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur, India
| | - Swarnendu Roy
- Department of Biological Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur, India
| | - Bipra Prasad Dey
- Department of Biological Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur, India
| | - Kaustav Gangopadhyay
- Department of Biological Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur, India
| | - Rahul Das
- Department of Biological Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur, India; Centre for Advanced Functional Materials, Indian Institute of Science Education and Research Kolkata, Mohanpur, India.
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2
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Lin DYW, Kueffer LE, Juneja P, Wales TE, Engen JR, Andreotti AH. Conformational heterogeneity of the BTK PHTH domain drives multiple regulatory states. eLife 2024; 12:RP89489. [PMID: 38189455 PMCID: PMC10945472 DOI: 10.7554/elife.89489] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2024] Open
Abstract
Full-length Bruton's tyrosine kinase (BTK) has been refractory to structural analysis. The nearest full-length structure of BTK to date consists of the autoinhibited SH3-SH2-kinase core. Precisely how the BTK N-terminal domains (the Pleckstrin homology/Tec homology [PHTH] domain and proline-rich regions [PRR] contain linker) contribute to BTK regulation remains unclear. We have produced crystals of full-length BTK for the first time but despite efforts to stabilize the autoinhibited state, the diffraction data still reveal only the SH3-SH2-kinase core with no electron density visible for the PHTH-PRR segment. Cryo-electron microscopy (cryoEM) data of full-length BTK, on the other hand, provide the first view of the PHTH domain within full-length BTK. CryoEM reconstructions support conformational heterogeneity in the PHTH-PRR region wherein the globular PHTH domain adopts a range of states arrayed around the autoinhibited SH3-SH2-kinase core. On the way to activation, disassembly of the SH3-SH2-kinase core opens a new autoinhibitory site on the kinase domain for PHTH domain binding that is ultimately released upon interaction of PHTH with phosphatidylinositol (3,4,5)-trisphosphate. Membrane-induced dimerization activates BTK and we present here a crystal structure of an activation loop swapped BTK kinase domain dimer that likely represents the conformational state leading to trans-autophosphorylation. Together, these data provide the first structural elucidation of full-length BTK and allow a deeper understanding of allosteric control over the BTK kinase domain during distinct stages of activation.
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Affiliation(s)
- David Yin-wei Lin
- Roy J. Carver Department of Biochemistry, Biophysics and Molecular Biology, Iowa State UniversityAmesUnited States
| | - Lauren E Kueffer
- Roy J. Carver Department of Biochemistry, Biophysics and Molecular Biology, Iowa State UniversityAmesUnited States
| | - Puneet Juneja
- Cryo-EM Facility, Office of Biotechnology, Iowa State UniversityAmesUnited States
| | - Thomas E Wales
- Department of Chemistry and Chemical Biology, Northeastern UniversityBostonUnited States
| | - John R Engen
- Department of Chemistry and Chemical Biology, Northeastern UniversityBostonUnited States
| | - Amy H Andreotti
- Roy J. Carver Department of Biochemistry, Biophysics and Molecular Biology, Iowa State UniversityAmesUnited States
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3
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Lin DYW, Kueffer LE, Juneja P, Wales TE, Engen JR, Andreotti AH. Conformational heterogeneity of the BTK PHTH domain drives multiple regulatory states. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.06.02.543453. [PMID: 37786675 PMCID: PMC10541622 DOI: 10.1101/2023.06.02.543453] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/04/2023]
Abstract
Full-length BTK has been refractory to structural analysis. The nearest full-length structure of BTK to date consists of the autoinhibited SH3-SH2-kinase core. Precisely how the BTK N-terminal domains (the Pleckstrin homology/Tec homology (PHTH) domain and proline-rich regions (PRR) contain linker) contribute to BTK regulation remains unclear. We have produced crystals of full-length BTK for the first time but despite efforts to stabilize the autoinhibited state, the diffraction data still reveals only the SH3-SH2-kinase core with no electron density visible for the PHTH-PRR segment. CryoEM data of full-length BTK, on the other hand, provide the first view of the PHTH domain within full-length BTK. CryoEM reconstructions support conformational heterogeneity in the PHTH-PRR region wherein the globular PHTH domain adopts a range of states arrayed around the autoinhibited SH3-SH2-kinase core. On the way to activation, disassembly of the SH3-SH2-kinase core opens a new autoinhibitory site on the kinase domain for PHTH domain binding that is ultimately released upon interaction of PHTH with PIP3. Membrane-induced dimerizationactivates BTK and we present here a crystal structure of an activation loop swapped BTK kinase domain dimer that likely represents the conformational state leading to transautophosphorylation. Together, these data provide the first structural elucidation of full-length BTK and allow a deeper understanding of allosteric control over the BTK kinase domain during distinct stages of activation.
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Yu J, Boehr DD. Regulatory mechanisms triggered by enzyme interactions with lipid membrane surfaces. Front Mol Biosci 2023; 10:1306483. [PMID: 38099197 PMCID: PMC10720463 DOI: 10.3389/fmolb.2023.1306483] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2023] [Accepted: 11/17/2023] [Indexed: 12/17/2023] Open
Abstract
Recruitment of enzymes to intracellular membranes often modulates their catalytic activity, which can be important in cell signaling and membrane trafficking. Thus, re-localization is not only important for these enzymes to gain access to their substrates, but membrane interactions often allosterically regulate enzyme function by inducing conformational changes across different time and amplitude scales. Recent structural, biophysical and computational studies have revealed how key enzymes interact with lipid membrane surfaces, and how this membrane binding regulates protein structure and function. This review summarizes the recent progress in understanding regulatory mechanisms involved in enzyme-membrane interactions.
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Affiliation(s)
| | - David D. Boehr
- Department of Chemistry, The Pennsylvania State University, University Park, PA, United States
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Aryal M, Lin D, Regan K, Du S, Shi H, Alvarado JJ, Ilina TV, Andreotti AH, Smithgall TE. The HIV-1 protein Nef activates the Tec family kinase Btk by stabilizing an intermolecular SH3-SH2 domain interaction. Sci Signal 2022; 15:eabn8359. [PMID: 36126115 PMCID: PMC9830684 DOI: 10.1126/scisignal.abn8359] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
The Nef protein produced by the viruses HIV-1 and SIV drives efficient viral replication partially by inducing constitutive activation of host cell tyrosine kinases, including members of the Src and Tec families. Here, we uncovered the mechanism by which both HIV-1 and SIV Nef enhanced the activity of the Tec family kinase Btk in vitro and in cells. A Nef mutant that could not bind to the SH3 domain of Src family kinases activated Btk to the same extent as did wild-type Nef, demonstrating that Nef activated Src and Tec family kinases by distinct mechanisms. The Btk SH3-SH2 region formed a homodimer requiring the CD loop in the SH2 domain, which was stabilized by the binding of Nef homodimers. Alanine substitution of Pro327 in the CD loop of the Btk SH2 domain destabilized SH3-SH2 dimers, abolished the interaction with Nef, and prevented activation by Nef in vitro. In cells, Nef stabilized and activated wild-type but not P327A Btk homodimers at the plasma membrane. These data reveal that the interaction with Nef stabilizes Btk dimers through the SH3-SH2 interface to promote kinase activity and show that the HIV-1 Nef protein evolved distinct mechanisms to activate Src and Tec family tyrosine kinases to enhance viral replication.
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Affiliation(s)
- Manish Aryal
- Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh PA, 15219 USA
| | - David Lin
- Roy J. Carver Department of Biochemistry, Biophysics and Molecular Biology, Iowa State University, Ames, IA, 50011 USA
| | - Kiera Regan
- Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh PA, 15219 USA
| | - Shoucheng Du
- Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh PA, 15219 USA
| | - Haibin Shi
- Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh PA, 15219 USA
| | - John J. Alvarado
- Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh PA, 15219 USA
| | - Tatiana V. Ilina
- Department of Structural Biology, University of Pittsburgh School of Medicine, Pittsburgh PA, 15260 USA
| | - Amy H. Andreotti
- Roy J. Carver Department of Biochemistry, Biophysics and Molecular Biology, Iowa State University, Ames, IA, 50011 USA
| | - Thomas E. Smithgall
- Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh PA, 15219 USA,To whom correspondence should be addressed: Thomas E. Smithgall, Ph.D., Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Bridgeside Point II, Suite 523, 450 Technology Drive, Pittsburgh, PA 15219, Tel. 412-648-8106, Fax 412-624-8997,
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Liang W, Li K, Zhang Q, Li K, Ai K, Zhang J, Jiao X, Li J, Wei X, Yang J. Interleukin-2 inducible T cell kinase (ITK) may participate in the anti-bacterial immune response of Nile tilapia via regulating T-cell activation. FISH & SHELLFISH IMMUNOLOGY 2022; 127:419-426. [PMID: 35779809 DOI: 10.1016/j.fsi.2022.06.044] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/21/2022] [Revised: 05/28/2022] [Accepted: 06/24/2022] [Indexed: 06/15/2023]
Abstract
Interleukin-2 inducible T cell kinase (ITK) plays a predominant role in the T-cell receptor (TCR) signaling cascade to ensure valid T-cell activation and function. Nevertheless, whether it regulates T-cell response of early vertebrates remains unknown. Herein, we investigated the involvement of ITK in the lymphocyte-mediated adaptive immune response, and its regulation to T-cell activation in the Nile tilapia Oreochromis niloticus. Both sequence and structure of O. niloticus ITK (OnITK) were remarkably conserved with its homologues from other vertebrates, implying its potential conserved function. OnITK mRNA was extensively expressed in lymphoid-related tissues, and with the relative highest level in peripheral blood. Once Nile tilapia was infected by Edwardsiella piscicida, OnITK in splenic lymphocytes was significantly up-regulated on 7-day post infection at both transcription and translation levels, suggesting that OnITK might involve in the primary adaptive immune response of teleost. Furthermore, upon splenic lymphocytes were stimulated by T-cell specific mitogen PHA, OnITK mRNA and protein levels were dramatically elevated. More importantly, treatment of splenic lymphocytes with specific inhibitor significantly crippled OnITK expression, which in turn impaired the inducible expression of T-cell activation markers IFN-γ, IL-2 and CD122, indicating the critical roles of ITK in regulating T-cell activation of Nile tilapia. Taken together, our results suggest that ITK takes part in the lymphocyte-mediated adaptive immunity of tilapia, and is indispensable for T-cell activation of teleost. Our findings thus provide novel evidences for understanding the mechanism regulating T-cell immunity of early vertebrates, as well as the evolution of adaptive immune system.
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Affiliation(s)
- Wei Liang
- State Key Laboratory of Estuarine and Coastal Research, School of Life Sciences, East China Normal University, Shanghai, 200241, China
| | - Kunming Li
- State Key Laboratory of Estuarine and Coastal Research, School of Life Sciences, East China Normal University, Shanghai, 200241, China
| | - Qian Zhang
- State Key Laboratory of Estuarine and Coastal Research, School of Life Sciences, East China Normal University, Shanghai, 200241, China
| | - Kang Li
- State Key Laboratory of Estuarine and Coastal Research, School of Life Sciences, East China Normal University, Shanghai, 200241, China
| | - Kete Ai
- State Key Laboratory of Estuarine and Coastal Research, School of Life Sciences, East China Normal University, Shanghai, 200241, China
| | - Jiansong Zhang
- State Key Laboratory of Estuarine and Coastal Research, School of Life Sciences, East China Normal University, Shanghai, 200241, China
| | - Xinying Jiao
- State Key Laboratory of Estuarine and Coastal Research, School of Life Sciences, East China Normal University, Shanghai, 200241, China
| | - Jiaqi Li
- State Key Laboratory of Estuarine and Coastal Research, School of Life Sciences, East China Normal University, Shanghai, 200241, China
| | - Xiumei Wei
- State Key Laboratory of Estuarine and Coastal Research, School of Life Sciences, East China Normal University, Shanghai, 200241, China.
| | - Jialong Yang
- State Key Laboratory of Estuarine and Coastal Research, School of Life Sciences, East China Normal University, Shanghai, 200241, China; Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, 266237, China
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7
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Lowe J, Joseph RE, Andreotti AH. Conformational switches that control the TEC kinase – PLCγ signaling axis. J Struct Biol X 2022; 6:100061. [PMID: 35128378 PMCID: PMC8803661 DOI: 10.1016/j.yjsbx.2022.100061] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2021] [Revised: 01/15/2022] [Accepted: 01/18/2022] [Indexed: 11/27/2022] Open
Abstract
TEC kinases and PLCγ transition between autoinhibited state and active conformation. PLCγ structures reveal both autoinhibited form and active form of gamma specific array (γSA); the four regulatory domains unique to the PLCγ isozymes. Domain dynamics likely control activation mechanism. PLCγ phosphorylation triggers conformational switch.
Cell surface receptors such as the T-cell receptor (TCR) and B-cell receptor (BCR) engage with external stimuli to transmit information into the cell and initiate a cascade of signaling events that lead to gene expression that drives the immune response. At the heart of controlling T- and B-cell cell signaling, phospholipase Cγ hydrolyzes membrane associated PIP2, leading to generation of the second messengers IP3 and DAG. These small molecules trigger mobilization of intracellular Ca2+ and promote transcription factor transport into the nucleus launching the adaptive immune response. The TEC family kinases are responsible for phosphorylating and activating PLCγ, and our group aims to understand mechanisms that regulate immune cell signal transduction by focusing on this kinase/phospholipase axis in T-cells and B-cells. Here, we review the current molecular level understanding of how the TEC kinases (ITK and BTK) and PLCγ1/2 are autoinhibited prior to activation of cell surface receptors, how TEC kinases are activated to specifically recognize the PLCγ substrate, and how conformational changes induced by phosphorylation trigger PLCγ activation.
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Kueffer LE, Joseph RE, Andreotti AH. Reining in BTK: Interdomain Interactions and Their Importance in the Regulatory Control of BTK. Front Cell Dev Biol 2021; 9:655489. [PMID: 34249912 PMCID: PMC8260988 DOI: 10.3389/fcell.2021.655489] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2021] [Accepted: 06/02/2021] [Indexed: 12/22/2022] Open
Abstract
Since Dr. Ogden Bruton's 1952 paper describing the first human primary immunodeficiency disease, the peripheral membrane binding signaling protein, aptly named Bruton's tyrosine kinase (BTK), has been the target of intense study. Dr. Bruton's description of agammaglobulinemia set the stage for ultimately understanding key signaling steps emanating from the B cell receptor. BTK is a multidomain tyrosine kinase and in the decades since Dr. Bruton's discovery it has become clear that genetic defects in the regulatory domains or the catalytic domain can lead to immunodeficiency. This finding underscores the intricate regulatory mechanisms within the BTK protein that maintain appropriate levels of signaling both in the resting B cell and during an immune challenge. In recent decades, BTK has become a target for clinical intervention in treating B cell malignancies. The survival reliance of B cell malignancies on B cell receptor signaling has allowed small molecules that target BTK to become essential tools in treating patients with hematological malignancies. The first-in-class Ibrutinib and more selective second-generation inhibitors all target the active site of the multidomain BTK protein. Therapeutic interventions targeting BTK have been successful but are plagued by resistance mutations that render drug treatment ineffective for some patients. This review will examine the molecular mechanisms that drive drug resistance, the long-range conformational effects of active site inhibitors on the BTK regulatory apparatus, and emerging opportunities to allosterically target the BTK kinase to improve therapeutic interventions using combination therapies.
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Affiliation(s)
| | | | - Amy H. Andreotti
- Roy J. Carver Department of Biochemistry, Biophysics and Molecular Biology, Iowa State University, Ames, IA, United States
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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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10
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Joseph RE, Amatya N, Fulton DB, Engen JR, Wales TE, Andreotti A. Differential impact of BTK active site inhibitors on the conformational state of full-length BTK. eLife 2020; 9:60470. [PMID: 33226337 PMCID: PMC7834017 DOI: 10.7554/elife.60470] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2020] [Accepted: 11/20/2020] [Indexed: 12/30/2022] Open
Abstract
Bruton’s tyrosine kinase (BTK) is targeted in the treatment of B-cell disorders including leukemias and lymphomas. Currently approved BTK inhibitors, including Ibrutinib, a first-in-class covalent inhibitor of BTK, bind directly to the kinase active site. While effective at blocking the catalytic activity of BTK, consequences of drug binding on the global conformation of full-length BTK are unknown. Here, we uncover a range of conformational effects in full-length BTK induced by a panel of active site inhibitors, including large-scale shifts in the conformational equilibria of the regulatory domains. Additionally, we find that a remote Ibrutinib resistance mutation, T316A in the BTK SH2 domain, drives spurious BTK activity by destabilizing the compact autoinhibitory conformation of full-length BTK, shifting the conformational ensemble away from the autoinhibited form. Future development of BTK inhibitors will need to consider long-range allosteric consequences of inhibitor binding, including the emerging application of these BTK inhibitors in treating COVID-19. Treatments for blood cancers, such as leukemia and lymphoma, rely heavily on chemotherapy, using drugs that target a vulnerable aspect of the cancer cells. B-cells, a type of white blood cell that produces antibodies, require a protein called Bruton’s tyrosine kinase, or BTK for short, to survive. The drug ibrutinib (Imbruvica) is used to treat B-cell cancers by blocking BTK. The BTK protein consists of several regions. One of them, known as the kinase domain, is responsible for its activity as an enzyme (which allows it to modify other proteins by adding a ‘tag’ known as a phosphate group). The other regions of BTK, known as regulatory modules, control this activity. In BTK’s inactive form, the regulatory modules attach to the kinase domain, blocking the regulatory modules from interacting with other proteins. When BTK is activated, it changes its conformation so the regulatory regions detach and become available for interactions with other proteins, at the same time exposing the active kinase domain. Ibrutinib and other BTK drugs in development bind to the kinase domain to block its activity. However, it is not known how this binding affects the regulatory modules. Previous efforts to study how drugs bind to BTK have used a version of the protein that only had the kinase domain, instead of the full-length protein. Now, Joseph et al. have studied full-length BTK and how it binds to five different drugs. The results reveal that ibrutinib and another drug called dasatinib both indirectly disrupt the normal position of the regulatory domains pushing BTK toward a conformation that resembles the activated state. By contrast, the three other compounds studied do not affect the inactive structure. Joseph et al. also examined a mutation in BTK that confers resistance against ibrutinib. This mutation increases the activity of BTK by disrupting the inactive structure, leading to B cells surviving better. Understanding how drug resistance mechanisms can work will lead to better drug treatment strategies for cancer. BTK is also a target in other diseases such as allergies or asthma and even COVID-19. If interactions between partner proteins and the regulatory domain are important in these diseases, then they may be better treated with drugs that maintain the regulatory modules in their inactive state. This research will help to design drugs that are better able to control BTK activity.
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Affiliation(s)
- Raji E Joseph
- Roy J. Carver Department of Biochemistry, Biophysics and Molecular Biology, Iowa State University, Ames, United States
| | - Neha Amatya
- Roy J. Carver Department of Biochemistry, Biophysics and Molecular Biology, Iowa State University, Ames, United States
| | - D Bruce Fulton
- Roy J. Carver Department of Biochemistry, Biophysics and Molecular Biology, Iowa State University, Ames, United States
| | - John R Engen
- Department of Chemistry and Chemical Biology, Northeastern University, Boston, United States
| | - Thomas E Wales
- Department of Chemistry and Chemical Biology, Northeastern University, Boston, United States
| | - Amy Andreotti
- Roy J. Carver Department of Biochemistry, Biophysics and Molecular Biology, Iowa State University, Ames, United States
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11
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Li WF, Aryal M, Shu ST, Smithgall TE. HIV-1 Nef dimers short-circuit immune receptor signaling by activating Tec-family kinases at the host cell membrane. J Biol Chem 2020; 295:5163-5174. [PMID: 32144207 DOI: 10.1074/jbc.ra120.012536] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2020] [Revised: 03/04/2020] [Indexed: 01/08/2023] Open
Abstract
The HIV-1 virulence factor Nef promotes high-titer viral replication, immune escape, and pathogenicity. Nef interacts with interleukin-2-inducible T-cell kinase (Itk) and Bruton's tyrosine kinase (Btk), two Tec-family kinases expressed in HIV-1 target cells (CD4 T cells and macrophages, respectively). Using a cell-based bimolecular fluorescence complementation assay, here we demonstrate that Nef recruits both Itk and Btk to the cell membrane and induces constitutive kinase activation in transfected 293T cells. Nef homodimerization-defective mutants retained their interaction with both kinases but failed to induce activation, supporting a role for Nef homodimer formation in the activation mechanism. HIV-1 infection up-regulates endogenous Itk activity in SupT1 T cells and donor-derived peripheral blood mononuclear cells. However, HIV-1 strains expressing Nef variants with mutations in the dimerization interface replicated poorly and were significantly attenuated in Itk activation. We conclude that direct activation of Itk and Btk by Nef at the membrane in HIV-infected cells may override normal immune receptor control of Tec-family kinase activity to enhance the viral life cycle.
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Affiliation(s)
- Wing Fai Li
- Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, 450 Technology Drive, Pittsburgh, Pennsylvania 15219
| | - Manish Aryal
- Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, 450 Technology Drive, Pittsburgh, Pennsylvania 15219
| | - Sherry T Shu
- Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, 450 Technology Drive, Pittsburgh, Pennsylvania 15219
| | - Thomas E Smithgall
- Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, 450 Technology Drive, Pittsburgh, Pennsylvania 15219
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Lipid-targeting pleckstrin homology domain turns its autoinhibitory face toward the TEC kinases. Proc Natl Acad Sci U S A 2019; 116:21539-21544. [PMID: 31591208 PMCID: PMC6815127 DOI: 10.1073/pnas.1907566116] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Bruton’s tyrosine kinase (BTK) is targeted in treatment of immune cancers. As patients experience drug resistance, there is a need for alternative approaches to inhibit BTK. Other recently published findings clarify the role of the BTK pleckstrin homology (PH) domain in mediating activation via dimerization and sensing of ligand concentration at the membrane. Work presented here provides insight into the autoinhibitory BTK structure that has so far been elusive via crystallographic methods. In the resting state, the BTK PH domain binds to the activation loop face of the kinase domain and allosterically alters key sites within the kinase domain. The findings define a new regulatory site, the PH/kinase interface, that can be exploited in drug discovery efforts. The pleckstrin homology (PH) domain is well known for its phospholipid targeting function. The PH-TEC homology (PHTH) domain within the TEC family of tyrosine kinases is also a crucial component of the autoinhibitory apparatus. The autoinhibitory surface on the PHTH domain has been previously defined, and biochemical investigations have shown that PHTH-mediated inhibition is mutually exclusive with phosphatidylinositol binding. Here we use hydrogen/deuterium exchange mass spectrometry, nuclear magnetic resonance (NMR), and evolutionary sequence comparisons to map where and how the PHTH domain affects the Bruton’s tyrosine kinase (BTK) domain. The data map a PHTH-binding site on the activation loop face of the kinase C lobe, suggesting that the PHTH domain masks the activation loop and the substrate-docking site. Moreover, localized NMR spectral changes are observed for non–surface-exposed residues in the active site and on the distal side of the kinase domain. These data suggest that the association of PHTH induces allosteric conformational shifts in regions of the kinase domain that are critical for catalysis. Through statistical comparisons of diverse tyrosine kinase sequences, we identify residues unique to BTK that coincide with the experimentally determined PHTH-binding surface on the kinase domain. Our data provide a more complete picture of the autoinhibitory conformation adopted by full-length TEC kinases, creating opportunities to target the regulatory domains to control the function of these kinases in a biological setting.
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13
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Andreotti AH, Joseph RE, Conley JM, Iwasa J, Berg LJ. Multidomain Control Over TEC Kinase Activation State Tunes the T Cell Response. Annu Rev Immunol 2019; 36:549-578. [PMID: 29677469 DOI: 10.1146/annurev-immunol-042617-053344] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Signaling through the T cell antigen receptor (TCR) activates a series of tyrosine kinases. Directly associated with the TCR, the SRC family kinase LCK and the SYK family kinase ZAP-70 are essential for all downstream responses to TCR stimulation. In contrast, the TEC family kinase ITK is not an obligate component of the TCR cascade. Instead, ITK functions as a tuning dial, to translate variations in TCR signal strength into differential programs of gene expression. Recent insights into TEC kinase structure have provided a view into the molecular mechanisms that generate different states of kinase activation. In resting lymphocytes, TEC kinases are autoinhibited, and multiple interactions between the regulatory and kinase domains maintain low activity. Following TCR stimulation, newly generated signaling modules compete with the autoinhibited core and shift the conformational ensemble to the fully active kinase. This multidomain control over kinase activation state provides a structural mechanism to account for ITK's ability to tune the TCR signal.
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Affiliation(s)
- Amy H Andreotti
- Roy J. Carver Department of Biochemistry, Biophysics and Molecular Biology, Iowa State University, Ames, Iowa 50011, USA; ,
| | - Raji E Joseph
- Roy J. Carver Department of Biochemistry, Biophysics and Molecular Biology, Iowa State University, Ames, Iowa 50011, USA; ,
| | - James M Conley
- Department of Pathology, University of Massachusetts Medical School, Worcester, Massachusetts 01655, USA; ,
| | - Janet Iwasa
- Department of Biochemistry, University of Utah, Salt Lake City, Utah 84112, USA;
| | - Leslie J Berg
- Department of Pathology, University of Massachusetts Medical School, Worcester, Massachusetts 01655, USA; ,
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14
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A Combined Approach Reveals a Regulatory Mechanism Coupling Src's Kinase Activity, Localization, and Phosphotransferase-Independent Functions. Mol Cell 2019; 74:393-408.e20. [PMID: 30956043 DOI: 10.1016/j.molcel.2019.02.003] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2018] [Revised: 11/20/2018] [Accepted: 01/31/2019] [Indexed: 02/06/2023]
Abstract
Multiple layers of regulation modulate the activity and localization of protein kinases. However, many details of kinase regulation remain incompletely understood. Here, we apply saturation mutagenesis and a chemical genetic method for allosterically modulating kinase global conformation to Src kinase, providing insight into known regulatory mechanisms and revealing a previously undiscovered interaction between Src's SH4 and catalytic domains. Abrogation of this interaction increased phosphotransferase activity, promoted membrane association, and provoked phosphotransferase-independent alterations in cell morphology. Thus, Src's SH4 domain serves as an intramolecular regulator coupling catalytic activity, global conformation, and localization, as well as mediating a phosphotransferase-independent function. Sequence conservation suggests that the SH4 domain regulatory interaction exists in other Src-family kinases. Our combined approach's ability to reveal a regulatory mechanism in one of the best-studied kinases suggests that it could be applied broadly to provide insight into kinase structure, regulation, and function.
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15
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Shah NH, Amacher JF, Nocka LM, Kuriyan J. The Src module: an ancient scaffold in the evolution of cytoplasmic tyrosine kinases. Crit Rev Biochem Mol Biol 2018; 53:535-563. [PMID: 30183386 PMCID: PMC6328253 DOI: 10.1080/10409238.2018.1495173] [Citation(s) in RCA: 49] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Tyrosine kinases were first discovered as the protein products of viral oncogenes. We now know that this large family of metazoan enzymes includes nearly one hundred structurally diverse members. Tyrosine kinases are broadly classified into two groups: the transmembrane receptor tyrosine kinases, which sense extracellular stimuli, and the cytoplasmic tyrosine kinases, which contain modular ligand-binding domains and propagate intracellular signals. Several families of cytoplasmic tyrosine kinases have in common a core architecture, the "Src module," composed of a Src-homology 3 (SH3) domain, a Src-homology 2 (SH2) domain, and a kinase domain. Each of these families is defined by additional elaborations on this core architecture. Structural, functional, and evolutionary studies have revealed a unifying set of principles underlying the activity and regulation of tyrosine kinases built on the Src module. The discovery of these conserved properties has shaped our knowledge of the workings of protein kinases in general, and it has had important implications for our understanding of kinase dysregulation in disease and the development of effective kinase-targeted therapies.
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Affiliation(s)
- Neel H. Shah
- Department of Molecular and Cell Biology, University of California, Berkeley, CA, USA
- Department of Chemistry, University of California, Berkeley, CA, USA
- California Institute for Quantitative Biosciences, University of California, Berkeley, CA, USA
- Howard Hughes Medical Institute, University of California, Berkeley, CA, USA
| | - Jeanine F. Amacher
- Department of Molecular and Cell Biology, University of California, Berkeley, CA, USA
- Department of Chemistry, University of California, Berkeley, CA, USA
- California Institute for Quantitative Biosciences, University of California, Berkeley, CA, USA
- Howard Hughes Medical Institute, University of California, Berkeley, CA, USA
| | - Laura M. Nocka
- Department of Molecular and Cell Biology, University of California, Berkeley, CA, USA
- Department of Chemistry, University of California, Berkeley, CA, USA
- California Institute for Quantitative Biosciences, University of California, Berkeley, CA, USA
- Howard Hughes Medical Institute, University of California, Berkeley, CA, USA
| | - John Kuriyan
- Department of Molecular and Cell Biology, University of California, Berkeley, CA, USA
- Department of Chemistry, University of California, Berkeley, CA, USA
- California Institute for Quantitative Biosciences, University of California, Berkeley, CA, USA
- Howard Hughes Medical Institute, University of California, Berkeley, CA, USA
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
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