1
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Nocka LM, Eisen TJ, Iavarone AT, Groves JT, Kuriyan J. Stimulation of the catalytic activity of the tyrosine kinase Btk by the adaptor protein Grb2. eLife 2023; 12:e82676. [PMID: 37159508 PMCID: PMC10132808 DOI: 10.7554/elife.82676] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2022] [Accepted: 04/03/2023] [Indexed: 05/11/2023] Open
Abstract
The Tec-family kinase Btk contains a lipid-binding Pleckstrin homology and Tec homology (PH-TH) module connected by a proline-rich linker to a 'Src module', an SH3-SH2-kinase unit also found in Src-family kinases and Abl. We showed previously that Btk is activated by PH-TH dimerization, which is triggered on membranes by the phosphatidyl inositol phosphate PIP3, or in solution by inositol hexakisphosphate (IP6) (Wang et al., 2015, https://doi.org/10.7554/eLife.06074). We now report that the ubiquitous adaptor protein growth-factor-receptor-bound protein 2 (Grb2) binds to and substantially increases the activity of PIP3-bound Btk on membranes. Using reconstitution on supported-lipid bilayers, we find that Grb2 can be recruited to membrane-bound Btk through interaction with the proline-rich linker in Btk. This interaction requires intact Grb2, containing both SH3 domains and the SH2 domain, but does not require that the SH2 domain be able to bind phosphorylated tyrosine residues - thus Grb2 bound to Btk is free to interact with scaffold proteins via the SH2 domain. We show that the Grb2-Btk interaction recruits Btk to scaffold-mediated signaling clusters in reconstituted membranes. Our findings indicate that PIP3-mediated dimerization of Btk does not fully activate Btk, and that Btk adopts an autoinhibited state at the membrane that is released by Grb2.
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Affiliation(s)
- Laura M Nocka
- Department of Chemistry, University of California, BerkeleyBerkeleyUnited States
- California Institute for Quantitative Biosciences, University of California, BerkeleyBerkeleyUnited States
- Howard Hughes Medical Institute, University of California, BerkeleyBerkeleyUnited States
| | - Timothy J Eisen
- Department of Chemistry, University of California, BerkeleyBerkeleyUnited States
- California Institute for Quantitative Biosciences, University of California, BerkeleyBerkeleyUnited States
- Department of Molecular and Cell Biology, University of California, BerkeleyBerkeleyUnited States
| | - Anthony T Iavarone
- California Institute for Quantitative Biosciences, University of California, BerkeleyBerkeleyUnited States
- College of Chemistry Mass Spectrometry Facility, University of California, BerkeleyBerkeleyUnited States
| | - Jay T Groves
- Department of Chemistry, University of California, BerkeleyBerkeleyUnited States
- California Institute for Quantitative Biosciences, University of California, BerkeleyBerkeleyUnited States
- Institute for Digital Molecular Analytics and Science, Nanyang Technological UniversitySingaporeSingapore
| | - John Kuriyan
- Department of Chemistry, University of California, BerkeleyBerkeleyUnited States
- California Institute for Quantitative Biosciences, University of California, BerkeleyBerkeleyUnited States
- Howard Hughes Medical Institute, University of California, BerkeleyBerkeleyUnited States
- Department of Molecular and Cell Biology, University of California, BerkeleyBerkeleyUnited States
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2
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Pathmanathan S, Yao Z, Coelho P, Valla R, Drecun L, Benz C, Snider J, Saraon P, Grozavu I, Kotlyar M, Jurisica I, Park M, Stagljar I. B cell linker protein (BLNK) is a regulator of Met receptor signaling and trafficking in non-small cell lung cancer. iScience 2022; 25:105419. [DOI: 10.1016/j.isci.2022.105419] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2022] [Revised: 08/16/2022] [Accepted: 10/18/2022] [Indexed: 11/06/2022] Open
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3
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Soini L, Leysen S, Davis J, Ottmann C. A biophysical and structural analysis of the interaction of BLNK with 14-3-3 proteins. J Struct Biol 2020; 212:107662. [PMID: 33176192 DOI: 10.1016/j.jsb.2020.107662] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2020] [Revised: 11/02/2020] [Accepted: 11/03/2020] [Indexed: 01/14/2023]
Abstract
B-cell linker protein (BLNK) is an adaptor protein that orchestrates signalling downstream of B-cell receptors. It has been reported to undergo proteasomal degradation upon binding to 14-3-3 proteins. Here, we report the first biophysical and structural study of this protein-protein interaction (PPI). Specifically, we investigated the binding of mono- and di- phosphorylated BLNK peptides to 14-3-3 using fluorescent polarization (FP) and isothermal titration calorimetry assays (ITC). Our results suggest that BLNK interacts with 14-3-3 according to the gatekeeper model, where HPK1 mediated phosphorylation of Thr152 (pT152) allows BLNK anchoring to 14-3-3, and an additional phosphorylation of Ser285 (pS285) by AKT, then further improves the affinity. Finally, we have also solved a crystal structure of the BLNKpT152 peptide bound to 14-3-3σ. These findings could serve as important tool for compound discovery programs aiming to modulate this interaction with 14-3-3.
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Affiliation(s)
- Lorenzo Soini
- Laboratory of Chemical Biology, Department of Biomedical Engineering and Institute for Complex Molecular Systems, Eindhoven University of Technology, Eindhoven, the Netherlands; Department of Chemistry, UCB Celltech, Slough, UK
| | - Seppe Leysen
- Department of Structural Biology and Biophysics, UCB Celltech, Slough, UK
| | - Jeremy Davis
- Department of Chemistry, UCB Celltech, Slough, UK
| | - Christian Ottmann
- Laboratory of Chemical Biology, Department of Biomedical Engineering and Institute for Complex Molecular Systems, Eindhoven University of Technology, Eindhoven, the Netherlands.
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4
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Wist M, Meier L, Gutman O, Haas J, Endres S, Zhou Y, Rösler R, Wiese S, Stilgenbauer S, Hobeika E, Henis YI, Gierschik P, Walliser C. Noncatalytic Bruton's tyrosine kinase activates PLCγ 2 variants mediating ibrutinib resistance in human chronic lymphocytic leukemia cells. J Biol Chem 2020; 295:5717-5736. [PMID: 32184360 DOI: 10.1074/jbc.ra119.011946] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2019] [Revised: 02/26/2020] [Indexed: 12/25/2022] Open
Abstract
Treatment of patients with chronic lymphocytic leukemia (CLL) with inhibitors of Bruton's tyrosine kinase (BTK), such as ibrutinib, is limited by primary or secondary resistance to this drug. Examinations of CLL patients with late relapses while on ibrutinib, which inhibits BTK's catalytic activity, revealed several mutations in BTK, most frequently resulting in the C481S substitution, and disclosed many mutations in PLCG2, encoding phospholipase C-γ2 (PLCγ2). The PLCγ2 variants typically do not exhibit constitutive activity in cell-free systems, leading to the suggestion that in intact cells they are hypersensitive to Rac family small GTPases or to the upstream kinases spleen-associated tyrosine kinase (SYK) and Lck/Yes-related novel tyrosine kinase (LYN). The sensitivity of the PLCγ2 variants to BTK itself has remained unknown. Here, using genetically-modified DT40 B lymphocytes, along with various biochemical assays, including analysis of PLCγ2-mediated inositol phosphate formation, inositol phospholipid assessments, fluorescence recovery after photobleaching (FRAP) static laser microscopy, and determination of intracellular calcium ([Ca2+] i ), we show that various CLL-specific PLCγ2 variants such as PLCγ2S707Y are hyper-responsive to activated BTK, even in the absence of BTK's catalytic activity and independently of enhanced PLCγ2 phospholipid substrate supply. At high levels of B-cell receptor (BCR) activation, which may occur in individual CLL patients, catalytically-inactive BTK restored the ability of the BCR to mediate increases in [Ca2+] i Because catalytically-inactive BTK is insensitive to active-site BTK inhibitors, the mechanism involving the noncatalytic BTK uncovered here may contribute to preexisting reduced sensitivity or even primary resistance of CLL to these drugs.
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Affiliation(s)
- Martin Wist
- Institute of Pharmacology and Toxicology, Ulm University Medical Center, 89081 Ulm, Germany
| | - Laura Meier
- Institute of Pharmacology and Toxicology, Ulm University Medical Center, 89081 Ulm, Germany
| | - Orit Gutman
- Department of Neurobiology, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv 69978, Israel
| | - Jennifer Haas
- Institute of Pharmacology and Toxicology, Ulm University Medical Center, 89081 Ulm, Germany
| | - Sascha Endres
- Institute of Pharmacology and Toxicology, Ulm University Medical Center, 89081 Ulm, Germany
| | - Yuan Zhou
- Institute of Pharmacology and Toxicology, Ulm University Medical Center, 89081 Ulm, Germany
| | - Reinhild Rösler
- Core Unit Mass Spectrometry and Proteomics, Medical Faculty, Ulm University Medical Center, 89081 Ulm, Germany
| | - Sebastian Wiese
- Core Unit Mass Spectrometry and Proteomics, Medical Faculty, Ulm University Medical Center, 89081 Ulm, Germany
| | - Stephan Stilgenbauer
- Department of Internal Medicine III, Ulm University Medical Center, 89081 Ulm, Germany
| | - Elias Hobeika
- Institute of Immunology, Ulm University Medical Center, 89081 Ulm, Germany
| | - Yoav I Henis
- Department of Neurobiology, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv 69978, Israel
| | - Peter Gierschik
- Institute of Pharmacology and Toxicology, Ulm University Medical Center, 89081 Ulm, Germany.
| | - Claudia Walliser
- Institute of Pharmacology and Toxicology, Ulm University Medical Center, 89081 Ulm, Germany.
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5
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Chakraborty S, Karasu E, Huber-Lang M. Complement After Trauma: Suturing Innate and Adaptive Immunity. Front Immunol 2018; 9:2050. [PMID: 30319602 PMCID: PMC6165897 DOI: 10.3389/fimmu.2018.02050] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2018] [Accepted: 08/20/2018] [Indexed: 12/21/2022] Open
Abstract
The overpowering effect of trauma on the immune system is undisputed. Severe trauma is characterized by systemic cytokine generation, activation and dysregulation of systemic inflammatory response complementopathy and coagulopathy, has been immensely instrumental in understanding the underlying mechanisms of the innate immune system during systemic inflammation. The compartmentalized functions of the innate and adaptive immune systems are being gradually recognized as an overlapping, interactive and dynamic system of responsive elements. Nonetheless the current knowledge of the complement cascade and its interaction with adaptive immune response mediators and cells, including T- and B-cells, is limited. In this review, we discuss what is known about the bridging effects of the complement system on the adaptive immune system and which unexplored areas could be crucial in understanding how the complement and adaptive immune systems interact following trauma.
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Affiliation(s)
- Shinjini Chakraborty
- Institute of Clinical and Experimental Trauma-Immunology, University Hospital of Ulm, Ulm, Germany
| | - Ebru Karasu
- Institute of Clinical and Experimental Trauma-Immunology, University Hospital of Ulm, Ulm, Germany
| | - Markus Huber-Lang
- Institute of Clinical and Experimental Trauma-Immunology, University Hospital of Ulm, Ulm, Germany
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6
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Keller B, Shoukier M, Schulz K, Bhatt A, Heine I, Strohmeier V, Speckmann C, Engels N, Warnatz K, Wienands J. Germline deletion of CIN85 in humans with X chromosome-linked antibody deficiency. J Exp Med 2018; 215:1327-1336. [PMID: 29636373 PMCID: PMC5940257 DOI: 10.1084/jem.20170534] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2017] [Revised: 07/20/2017] [Accepted: 03/15/2018] [Indexed: 12/13/2022] Open
Abstract
Despite the numerous cellular functions attributed to the scaffolding protein CIN85, Keller et al. show that an inactivating germline deletion within the human CIN85 gene causes a remarkably specific defect in the activation of B lymphocytes, preventing proper immune responses. Ubiquitously expressed Cbl-interacting protein of 85 kD (CIN85) is a multifunctional adapter molecule supposed to regulate numerous cellular processes that are critical for housekeeping as well as cell type–specific functions. However, limited information exists about the in vivo roles of CIN85, because only conditional mouse mutants with cell type–specific ablation of distinct CIN85 isoforms in brain and B lymphocytes have been generated so far. No information is available about the roles of CIN85 in humans. Here, we report on primary antibody deficiency in patients harboring a germline deletion within the CIN85 gene on the X chromosome. In the absence of CIN85, all immune cell compartments developed normally, but B lymphocytes showed intrinsic defects in distinct effector pathways of the B cell antigen receptor, most notably NF-κB activation and up-regulation of CD86 expression on the cell surface. These results reveal nonredundant functions of CIN85 for humoral immune responses.
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Affiliation(s)
- Baerbel Keller
- Center for Chronic Immunodeficiency, Medical Center-University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Moneef Shoukier
- Institute of Human Genetics, University Medical Center Göttingen, Göttingen, Germany
| | - Kathrin Schulz
- Institute of Cellular & Molecular Immunology, University Medical Center Göttingen, Göttingen, Germany
| | - Arshiya Bhatt
- Institute of Cellular & Molecular Immunology, University Medical Center Göttingen, Göttingen, Germany
| | - Ines Heine
- Institute of Cellular & Molecular Immunology, University Medical Center Göttingen, Göttingen, Germany
| | - Valentina Strohmeier
- Center for Chronic Immunodeficiency, Medical Center-University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Carsten Speckmann
- Institute of Human Genetics, University Medical Center Göttingen, Göttingen, Germany
| | - Niklas Engels
- Institute of Cellular & Molecular Immunology, University Medical Center Göttingen, Göttingen, Germany
| | - Klaus Warnatz
- Center for Chronic Immunodeficiency, Medical Center-University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Jürgen Wienands
- Institute of Cellular & Molecular Immunology, University Medical Center Göttingen, Göttingen, Germany
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7
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Sharma S, Galanina N, Guo A, Lee J, Kadri S, Van Slambrouck C, Long B, Wang W, Ming M, Furtado LV, Segal JP, Stock W, Venkataraman G, Tang WJ, Lu P, Wang YL. Identification of a structurally novel BTK mutation that drives ibrutinib resistance in CLL. Oncotarget 2018; 7:68833-68841. [PMID: 27626698 PMCID: PMC5356593 DOI: 10.18632/oncotarget.11932] [Citation(s) in RCA: 57] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2016] [Accepted: 08/15/2016] [Indexed: 12/01/2022] Open
Abstract
Ibrutinib (ibr), a first-in-class Bruton tyrosine kinase (BTK) inhibitor, has demonstrated high response rates in both relapsed/refractory and treatment naïve chronic lymphocytic leukemia (CLL). However, about 25% of patients discontinue ibrutinib therapy at a median follow-up of 20 months and many patients discontinue the treatment due to leukemia progression or Richter transformation. Mutations affecting the C481 residue of BTK disrupt ibrutinib binding and have been characterized by us and others as the most common mechanism of ibrutinib resistance. Thus far, all described BTK mutations are located in its kinase domain and mutations outside this domain have never been described. Herein, we report a patient whose CLL progressed, was salvaged with ibrutinib and then relapsed. Serial analysis of samples throughout patient's clinical course identified a structurally novel mutation (BTKT316A) in the SH2 domain, but not kinase domain, of Bruton tyrosine kinase which was associated with disease relapse. Functionally, cells carrying BTKT316A show resistance to ibrutinib at both cellular and molecular levels to a similar extent as BTKC481S. Our study lends further insight into the diverse mechanisms of ibrutinib resistance that has important implications for the development of next-generation BTK inhibitors as well as mutation detection in relapsed patients.
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Affiliation(s)
- Shruti Sharma
- Department of Pathology, University of Chicago, Chicago, IL 60637, USA
| | - Natalie Galanina
- Department of Medicine, University of Chicago, Chicago, IL 60637, USA
| | - Ailin Guo
- Department of Pathology, University of Chicago, Chicago, IL 60637, USA
| | - Jimmy Lee
- Department of Pathology, University of Chicago, Chicago, IL 60637, USA
| | - Sabah Kadri
- Department of Pathology, University of Chicago, Chicago, IL 60637, USA.,Center for Research Informatics, University of Chicago, Chicago, IL 60637, USA
| | | | - Bradley Long
- Department of Pathology, University of Chicago, Chicago, IL 60637, USA
| | - Weige Wang
- Department of Pathology, University of Chicago, Chicago, IL 60637, USA
| | - Mei Ming
- Department of Pathology, University of Chicago, Chicago, IL 60637, USA
| | - Larissa V Furtado
- Department of Pathology, University of Chicago, Chicago, IL 60637, USA
| | - Jeremy P Segal
- Department of Pathology, University of Chicago, Chicago, IL 60637, USA
| | - Wendy Stock
- Department of Medicine, University of Chicago, Chicago, IL 60637, USA
| | | | - Wei-Jen Tang
- Ben-May Department for Cancer Research, University of Chicago, Chicago, IL 60637, USA
| | - Pin Lu
- Department of Pathology, University of Chicago, Chicago, IL 60637, USA
| | - Yue Lynn Wang
- Department of Pathology, University of Chicago, Chicago, IL 60637, USA
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8
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Chen H, Song P, Diao Y, Hao Y, Dou D, Wang W, Fang X, Wang Y, Zhao Z, Ding J, Li H, Xie H, Xu Y. Discovery and biological evaluation of N5-substituted 6,7-dioxo-6,7-dihydropteridine derivatives as potent Bruton's tyrosine kinase inhibitors. MEDCHEMCOMM 2018; 9:697-704. [PMID: 30108960 DOI: 10.1039/c8md00019k] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/12/2018] [Accepted: 03/06/2018] [Indexed: 11/21/2022]
Abstract
Bruton's tyrosine kinase (BTK) plays a critical role in B cell receptor (BCR)-mediated signaling pathways responsible for the development and function of B cells, which makes it an attractive target for the treatment of many types of B-cell malignancies. Herein, a series of N5-substituted 6,7-dioxo-6,7-dihydropteridine-based, irreversible BTK inhibitors were reported with IC50 values ranging from 1.9 to 236.6 nM in the enzymatic inhibition assay. Compounds 6 and 7 significantly inhibited the proliferation of Ramos cells which overexpress the BTK enzyme, as well as the autophosphorylation of BTK at Tyr223 and the activation of its downstream signaling molecule PLCγ2. Overall, this series of compounds could provide a promising starting point for further development of potent BTK inhibitors for B-cell malignancy treatment.
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Affiliation(s)
- Haiyang Chen
- Shanghai Key Laboratory of New Drug Design , State Key Laboratory of Bioreactor Engineering , School of Pharmacy , East China University of Science & Technology , Shanghai 200237 , China . ; ; ; Tel: +86 21 64250213
| | - Peiran Song
- Division of Anti-tumor Pharmacology , State Key Laboratory of Drug Research , Shanghai Institute of Materia Medica , Chinese Academy of Sciences , Shanghai 201203 , China . .,University of Chinese Academy of Sciences , Beijing 100049 , China.,School of Life Science and Technology , ShanghaiTech University , Shanghai 201210 , China
| | - Yanyan Diao
- Shanghai Key Laboratory of New Drug Design , State Key Laboratory of Bioreactor Engineering , School of Pharmacy , East China University of Science & Technology , Shanghai 200237 , China . ; ; ; Tel: +86 21 64250213
| | - Yongjia Hao
- Shanghai Key Laboratory of New Drug Design , State Key Laboratory of Bioreactor Engineering , School of Pharmacy , East China University of Science & Technology , Shanghai 200237 , China . ; ; ; Tel: +86 21 64250213
| | - Dou Dou
- Shanghai Key Laboratory of New Drug Design , State Key Laboratory of Bioreactor Engineering , School of Pharmacy , East China University of Science & Technology , Shanghai 200237 , China . ; ; ; Tel: +86 21 64250213
| | - Wanqi Wang
- Shanghai Key Laboratory of New Drug Design , State Key Laboratory of Bioreactor Engineering , School of Pharmacy , East China University of Science & Technology , Shanghai 200237 , China . ; ; ; Tel: +86 21 64250213
| | - Xiaoyu Fang
- Shanghai Key Laboratory of New Drug Design , State Key Laboratory of Bioreactor Engineering , School of Pharmacy , East China University of Science & Technology , Shanghai 200237 , China . ; ; ; Tel: +86 21 64250213
| | - Yanling Wang
- Shanghai Key Laboratory of New Drug Design , State Key Laboratory of Bioreactor Engineering , School of Pharmacy , East China University of Science & Technology , Shanghai 200237 , China . ; ; ; Tel: +86 21 64250213
| | - Zhenjiang Zhao
- Shanghai Key Laboratory of New Drug Design , State Key Laboratory of Bioreactor Engineering , School of Pharmacy , East China University of Science & Technology , Shanghai 200237 , China . ; ; ; Tel: +86 21 64250213
| | - Jian Ding
- Division of Anti-tumor Pharmacology , State Key Laboratory of Drug Research , Shanghai Institute of Materia Medica , Chinese Academy of Sciences , Shanghai 201203 , China .
| | - Honglin Li
- Shanghai Key Laboratory of New Drug Design , State Key Laboratory of Bioreactor Engineering , School of Pharmacy , East China University of Science & Technology , Shanghai 200237 , China . ; ; ; Tel: +86 21 64250213
| | - Hua Xie
- Division of Anti-tumor Pharmacology , State Key Laboratory of Drug Research , Shanghai Institute of Materia Medica , Chinese Academy of Sciences , Shanghai 201203 , China .
| | - Yufang Xu
- Shanghai Key Laboratory of New Drug Design , State Key Laboratory of Bioreactor Engineering , School of Pharmacy , East China University of Science & Technology , Shanghai 200237 , China . ; ; ; Tel: +86 21 64250213
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9
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Unperturbed Immune Function despite Mutation of C-Terminal Tyrosines in Syk Previously Implicated in Signaling and Activity Regulation. Mol Cell Biol 2017; 37:MCB.00216-17. [PMID: 28760774 DOI: 10.1128/mcb.00216-17] [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: 04/28/2017] [Accepted: 07/26/2017] [Indexed: 11/20/2022] Open
Abstract
The nonreceptor tyrosine kinase Syk, a central regulator of immune cell differentiation and activation, is a promising drug target for treatment of leukemia and allergic and inflammatory diseases. The clinical failure of Syk inhibitors underscores the importance of understanding the regulation of Syk function and activity. A series of previous studies emphasized the importance of three C-terminal tyrosines in Syk for kinase activity regulation, as docking sites for downstream effector molecules, and for Ca2+ mobilization. Here, we investigated the roles of these C-terminal tyrosines in the mouse. Surprisingly, expression of a triple tyrosine-to-phenylalanine human Syk mutant, SYK(Y3F), was not associated with discernible signaling defects either in reconstituted DT40 cells or in B or mast cells from mice expressing SYK(Y3F) instead of wild-type Syk. Remarkably, lymphocyte differentiation, calcium mobilization, and 2,4,6-trinitrophenyl (TNP)-specific immune responses were unperturbed in SYK(Y3F) mice. These results emphasize the capacity of immune cells to compensate for specific molecular defects, likely using redundant intermolecular interactions, and highlight the importance of in vivo analyses for understanding cellular signaling mechanisms.
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10
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Shaheen S, Wan Z, Li Z, Chau A, Li X, Zhang S, Liu Y, Yi J, Zeng Y, Wang J, Chen X, Xu L, Chen W, Wang F, Lu Y, Zheng W, Shi Y, Sun X, Li Z, Xiong C, Liu W. Substrate stiffness governs the initiation of B cell activation by the concerted signaling of PKCβ and focal adhesion kinase. eLife 2017; 6. [PMID: 28755662 PMCID: PMC5536945 DOI: 10.7554/elife.23060] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2016] [Accepted: 07/03/2017] [Indexed: 12/17/2022] Open
Abstract
The mechanosensing ability of lymphocytes regulates their activation in response to antigen stimulation, but the underlying mechanism remains unexplored. Here, we report that B cell mechanosensing-governed activation requires BCR signaling molecules. PMA-induced activation of PKCβ can bypass the Btk and PLC-γ2 signaling molecules that are usually required for B cells to discriminate substrate stiffness. Instead, PKCβ-dependent activation of FAK is required, leading to FAK-mediated potentiation of B cell spreading and adhesion responses. FAK inactivation or deficiency impaired B cell discrimination of substrate stiffness. Conversely, adhesion molecules greatly enhanced this capability of B cells. Lastly, B cells derived from rheumatoid arthritis (RA) patients exhibited an altered BCR response to substrate stiffness in comparison with healthy controls. These results provide a molecular explanation of how initiation of B cell activation discriminates substrate stiffness through a PKCβ-mediated FAK activation dependent manner.
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Affiliation(s)
- Samina Shaheen
- MOE Key Laboratory of Protein Sciences, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, School of Life Sciences, Institute for Immunology, Tsinghua University, Beijing, China
| | - Zhengpeng Wan
- MOE Key Laboratory of Protein Sciences, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, School of Life Sciences, Institute for Immunology, Tsinghua University, Beijing, China
| | - Zongyu Li
- MOE Key Laboratory of Protein Sciences, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, School of Life Sciences, Institute for Immunology, Tsinghua University, Beijing, China
| | - Alicia Chau
- Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, China
| | - Xinxin Li
- MOE Key Laboratory of Protein Sciences, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, School of Life Sciences, Institute for Immunology, Tsinghua University, Beijing, China
| | - Shaosen Zhang
- MOE Key Laboratory of Protein Sciences, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, School of Life Sciences, Institute for Immunology, Tsinghua University, Beijing, China
| | - Yang Liu
- MOE Key Laboratory of Protein Sciences, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, School of Life Sciences, Institute for Immunology, Tsinghua University, Beijing, China
| | - Junyang Yi
- MOE Key Laboratory of Protein Sciences, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, School of Life Sciences, Institute for Immunology, Tsinghua University, Beijing, China
| | - Yingyue Zeng
- MOE Key Laboratory of Protein Sciences, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, School of Life Sciences, Institute for Immunology, Tsinghua University, Beijing, China
| | - Jing Wang
- MOE Key Laboratory of Protein Sciences, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, School of Life Sciences, Institute for Immunology, Tsinghua University, Beijing, China
| | - Xiangjun Chen
- MOE Key Laboratory of Protein Sciences, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, School of Life Sciences, Institute for Immunology, Tsinghua University, Beijing, China
| | - Liling Xu
- MOE Key Laboratory of Protein Sciences, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, School of Life Sciences, Institute for Immunology, Tsinghua University, Beijing, China
| | - Wei Chen
- School of Medicine, Zhejiang University, Hangzhou, China
| | - Fei Wang
- Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu, China
| | - Yun Lu
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing, China
| | - Wenjie Zheng
- Department of Rheumatology and Clinical Immunology, Peking Union Medical College Hospital, Peking Union Medical College and Chinese Academy of Medical Sciences, Beijing, China
| | - Yan Shi
- Center for Life Sciences, Department of Basic Medical Sciences, Institute of Immunology, Tsinghua University, Beijing, China
| | - Xiaolin Sun
- Department of Rheumatology and Immunology, Clinical Immunology Center, Peking University People's Hospital, Beijing, China
| | - Zhanguo Li
- Department of Rheumatology and Immunology, Clinical Immunology Center, Peking University People's Hospital, Beijing, China
| | - Chunyang Xiong
- Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, China.,College of Engineering, Peking University, Beijing, China
| | - Wanli Liu
- MOE Key Laboratory of Protein Sciences, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, School of Life Sciences, Institute for Immunology, Tsinghua University, Beijing, China
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11
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Musumeci F, Sanna M, Greco C, Giacchello I, Fallacara AL, Amato R, Schenone S. Pyrrolo[2,3-d]pyrimidines active as Btk inhibitors. Expert Opin Ther Pat 2017; 27:1305-1318. [DOI: 10.1080/13543776.2017.1355908] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Affiliation(s)
- Francesca Musumeci
- Dipartimento di Farmacia, Università degli Studi di Genova, Genova, Italy
| | - Monica Sanna
- Dipartimento di Farmacia, Università degli Studi di Genova, Genova, Italy
| | - Chiara Greco
- Dipartimento di Farmacia, Università degli Studi di Genova, Genova, Italy
| | - Ilaria Giacchello
- Dipartimento di Farmacia, Università degli Studi di Genova, Genova, Italy
| | - Anna Lucia Fallacara
- Dipartimento di Biotecnologie, Chimica e Farmacia, Università degli Studi di Siena, Siena, Italy
| | - Rosario Amato
- Dipartimento di “Scienze della Salute”, Università “Magna Graecia” di Catanzaro, Catanzaro, Italy
| | - Silvia Schenone
- Dipartimento di Farmacia, Università degli Studi di Genova, Genova, Italy
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12
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Mohammad DK, Nore BF, Gustafsson MO, Mohamed AJ, Smith CIE. Protein kinase B (AKT) regulates SYK activity and shuttling through 14-3-3 and importin 7. Int J Biochem Cell Biol 2016; 78:63-74. [PMID: 27381982 DOI: 10.1016/j.biocel.2016.06.024] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2016] [Revised: 05/24/2016] [Accepted: 06/30/2016] [Indexed: 01/10/2023]
Abstract
The Protein kinase B (AKT) regulates a plethora of intracellular signaling proteins to fine-tune signaling of multiple pathways. Here, we found that following B-cell receptor (BCR)-induced tyrosine phosphorylation of the cytoplasmic tyrosine kinase SYK and the adaptor BLNK, the AKT/PKB enzyme strongly induced BLNK (>100-fold) and SYK (>100-fold) serine/threonine phosphorylation (pS/pT). Increased phosphorylation promoted 14-3-3 binding to BLNK (37-fold) and SYK (2.5-fold) in a pS/pT-concentration dependent manner. We also demonstrated that the AKT inhibitor MK2206 reduced pS/pT of both BLNK (3-fold) and SYK (2.5-fold). Notably, the AKT phosphatase, PHLPP2 maintained the activating phosphorylation of BLNK at Y84 and increased protein stability (8.5-fold). In addition, 14-3-3 was required for the regulation SYK's interaction with BLNK and attenuated SYK binding to Importin 7 (5-fold), thereby perturbing shuttling to the nucleus. Moreover, 14-3-3 proteins also sustained tyrosine phosphorylation of SYK and BLNK. Furthermore, substitution of S295 or S297 for alanine abrogated SYK's binding to Importin 7. SYK with S295A or S297A replacements showed intense pY525/526 phosphorylation, and BLNK pY84 phosphorylation correlated with the SYK pY525/526 phosphorylation level. Conversely, the corresponding mutations to aspartic acid in SYK reduced pY525/526 phosphorylation. Collectively, these and previous results suggest that AKT and 14-3-3 proteins down-regulate the activity of several BCR-associated components, including BTK, BLNK and SYK and also inhibit SYK's interaction with Importin 7.
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Affiliation(s)
- Dara K Mohammad
- Department of Laboratory Medicine, Clinical Research Center, Karolinska Institutet, Karolinska Hospital Huddinge, SE-141 86 Huddinge, Stockholm, Sweden; Department of Biology, College of Science, University of Salahaddin, Erbil, Kurdistan Region, Iraq.
| | - Beston F Nore
- Department of Laboratory Medicine, Clinical Research Center, Karolinska Institutet, Karolinska Hospital Huddinge, SE-141 86 Huddinge, Stockholm, Sweden; Department of Biochemistry, School of Medicine, University of Sulaimani, Sulaimaniyah, Kurdistan Region, Iraq
| | - Manuela O Gustafsson
- Department of Laboratory Medicine, Clinical Research Center, Karolinska Institutet, Karolinska Hospital Huddinge, SE-141 86 Huddinge, Stockholm, Sweden
| | - Abdalla J Mohamed
- Universiti Brunei Darussalam, Environmental and Life Sciences, Faculty of Science, Jalan Tungku Link, Gadong BE1410 Negara Brunei Darussalam, Brunei
| | - C I Edvard Smith
- Department of Laboratory Medicine, Clinical Research Center, Karolinska Institutet, Karolinska Hospital Huddinge, SE-141 86 Huddinge, Stockholm, Sweden.
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13
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Levit-Zerdoun E, Becker M, Pohlmeyer R, Wilhelm I, Maity PC, Rajewsky K, Reth M, Hobeika E. Survival of Igα-Deficient Mature B Cells Requires BAFF-R Function. THE JOURNAL OF IMMUNOLOGY 2016; 196:2348-60. [PMID: 26843325 DOI: 10.4049/jimmunol.1501707] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/29/2015] [Accepted: 12/29/2015] [Indexed: 12/18/2022]
Abstract
Expression of a functional BCR is essential for the development of mature B cells and has been invoked in the control of their maintenance. To test this maintenance function in a new experimental setting, we used the tamoxifen-inducible mb1-CreER(T2) mouse strain to delete or truncate either the mb-1 gene encoding the BCR signaling subunit Igα or the VDJ segment of the IgH (H chain [HC]). In this system, Cre-mediated deletion of the mb-1 gene is accompanied by expression of a GFP reporter. We found that, although the Igα-deficient mature B cells survive for >20 d in vivo, the HC-deficient or Igα tail-truncated B cell population is short-lived, with the HC-deficient cells displaying signs of an unfolded protein response. We also show that Igα-deficient B cells still respond to the prosurvival factor BAFF in culture and require BAFF-R signaling for their in vivo maintenance. These results suggest that, under certain conditions, the loss of the BCR can be tolerated by mature B cells for some time, whereas HC-deficient B cells, potentially generated by aberrant somatic mutations in the germinal center, are rapidly eliminated.
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Affiliation(s)
- Ella Levit-Zerdoun
- Max Planck Institute of Immunobiology and Epigenetics, 79108 Freiburg, Germany; Department of Molecular Immunology, Biology III, Faculty of Biology, Albert-Ludwigs-University Freiburg, 79104 Freiburg, Germany; International Max Planck Research School for Molecular and Cellular Biology, 79108 Freiburg, Germany
| | - Martin Becker
- Max Planck Institute of Immunobiology and Epigenetics, 79108 Freiburg, Germany; Department of Molecular Immunology, Biology III, Faculty of Biology, Albert-Ludwigs-University Freiburg, 79104 Freiburg, Germany; International Max Planck Research School for Molecular and Cellular Biology, 79108 Freiburg, Germany
| | - Roland Pohlmeyer
- Max Planck Institute of Immunobiology and Epigenetics, 79108 Freiburg, Germany; Department of Molecular Immunology, Biology III, Faculty of Biology, Albert-Ludwigs-University Freiburg, 79104 Freiburg, Germany; Centre for Biological Signaling Studies, University of Freiburg, 79104 Freiburg, Germany
| | - Isabel Wilhelm
- Department of Molecular Immunology, Biology III, Faculty of Biology, Albert-Ludwigs-University Freiburg, 79104 Freiburg, Germany; Centre for Biological Signaling Studies, University of Freiburg, 79104 Freiburg, Germany; Spemann Graduate School of Biology and Medicine, Albert-Ludwigs-University Freiburg, 79104 Freiburg, Germany
| | - Palash Chandra Maity
- Max Planck Institute of Immunobiology and Epigenetics, 79108 Freiburg, Germany; Department of Molecular Immunology, Biology III, Faculty of Biology, Albert-Ludwigs-University Freiburg, 79104 Freiburg, Germany; Centre for Biological Signaling Studies, University of Freiburg, 79104 Freiburg, Germany
| | - Klaus Rajewsky
- Max Delbrück Center for Molecular Medicine, 13125 Berlin, Germany; and
| | - Michael Reth
- Max Planck Institute of Immunobiology and Epigenetics, 79108 Freiburg, Germany; Department of Molecular Immunology, Biology III, Faculty of Biology, Albert-Ludwigs-University Freiburg, 79104 Freiburg, Germany; Centre for Biological Signaling Studies, University of Freiburg, 79104 Freiburg, Germany;
| | - Elias Hobeika
- Max Planck Institute of Immunobiology and Epigenetics, 79108 Freiburg, Germany; Centre for Biological Signaling Studies, University of Freiburg, 79104 Freiburg, Germany; Institute of Immunology, University Hospital Ulm, 89081 Ulm, Germany
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14
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Kang MM, Shan SL, Wen XY, Shan HS, Wang ZJ. Tumor-Suppression Mechanisms of Protein Tyrosine Phosphatase O and Clinical Applications. Asian Pac J Cancer Prev 2015; 16:6215-23. [PMID: 26434819 DOI: 10.7314/apjcp.2015.16.15.6215] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
Tyrosine phosphorylation plays an important role in regulating human physiological and pathological processes. Functional stabilization of tyrosine phosphorylation largely contributes to the balanced, coordinated regulation of protein tyrosine kinases (PTKs) and protein tyrosine phosphatases (PTPs). Research has revealed PTPs play an important suppressive role in carcinogenesis and progression by reversing oncoprotein functions. Receptor-type protein tyrosine phosphatase O (PTPRO) as one member of the PTPs family has also been identified to have some roles in tumor development. Some reports have shown PTPRO over-expression in tumors can not only inhibit the frequency of tumor cell division and induce tumor cell death, but also suppress migration. However, the tumor-suppression mechanisms are very complex and understanding is incomplete, which in some degree blocks the further development of PTPRO. Hence, in order to resolve this problem, we here have summarized research findings to draw meaningful conclusions. We found tumor-suppression mechanisms of PTPRO to be diverse, such as controlling G0/G1 of the tumor cell proliferation cycle, inhibiting substrate phosphorylation, down-regulating transcription activators and other activities. In clinical anticancer efforts, expression level of PTPRO in tumors can not only serve as a biomarker to monitor the prognosis of patients, but act as an epigenetic biomarker for noninvasive diagnosis. In addition, the re-activation of PTPRO in tumor tissues, not only can induce tumor volume reduction, but also enhance the susceptibility to chemotherapy drugs. So, we can propose that these research findings of PTPRO will not only support new study ideas and directions for other tumor- suppressors, importantly, but also supply a theoretical basis for researching new molecular targeting agents in the future.
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Affiliation(s)
- Man-Man Kang
- The Center of Radiation Oncology, the 82th Hospital of People's Liberation Army of China, Huaian, Jiangsu, China E-mail : ,
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15
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Mato A, Jauhari S, Schuster SJ. Management of chronic lymphocytic leukemia (CLL) in the era of B-cell receptor signal transduction inhibitors. Am J Hematol 2015; 90:657-64. [PMID: 25808792 DOI: 10.1002/ajh.24021] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2015] [Revised: 03/16/2015] [Accepted: 03/17/2015] [Indexed: 02/01/2023]
Abstract
The treatment of patients with chronic lymphocytic leukemia (CLL), an indolent B-cell lymphoma is in the midst of a transformation. There are a large number of promising new therapeutic agents and cellular therapies being studied which exhibit remarkable activity, favorable toxicity profiles, convenient administration schedules, and treatment options are rapidly expanding. The recent advances in the management of CLL exemplify the value of translational medicine. This review highlights key aspects of B-cell receptor (BCR) signaling in relation to novel inhibitors of the BCR signaling pathway, currently at various stages of preclinical and clinical development.
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Affiliation(s)
- Anthony Mato
- Center for Chronic Lymphocytic Leukemia and Lymphoma Program; Abramson Cancer Center of the University of Pennsylvania; Philadelphia PA
| | - Shekeab Jauhari
- Center for Chronic Lymphocytic Leukemia and Lymphoma Program; Abramson Cancer Center of the University of Pennsylvania; Philadelphia PA
| | - Stephen J. Schuster
- Center for Chronic Lymphocytic Leukemia and Lymphoma Program; Abramson Cancer Center of the University of Pennsylvania; Philadelphia PA
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16
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Oksvold MP, Duyvestyn JM, Dagger SA, Taylor SJ, Forfang L, Myklebust JH, Smeland EB, Langdon WY. The targeting of human and mouse B lymphocytes by dasatinib. Exp Hematol 2015; 43:352-363.e4. [DOI: 10.1016/j.exphem.2015.01.008] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2014] [Revised: 01/19/2015] [Accepted: 01/21/2015] [Indexed: 10/24/2022]
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17
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Ortiz-Maldonado V, García-Morillo M, Delgado J. The biology behind PI3K inhibition in chronic lymphocytic leukaemia. Ther Adv Hematol 2015; 6:25-36. [PMID: 25642313 DOI: 10.1177/2040620714561581] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Phosphoinositide 3'-kinase (PI3K) is a key component of both chronic active and tonic B-cell receptor-signalling pathways. As such, PI3K inhibitors have emerged as promising therapeutic agents for diverse lymphoid malignancies, particularly chronic lymphocytic leukaemia. Multiple in vitro experiments and clinical trials have shown efficacy of these agents across all prognostic subgroups with a favourable toxicity profile. Moreover, in vitro studies suggest that combinations with monoclonal antibodies and/or other immune strategies could enhance the effect of PI3K inhibition.
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Affiliation(s)
| | - Marcial García-Morillo
- Hospital Clínic, Department of Medical Oncology Calle Villarroel, 170 08036 Barcelona, Spain
| | - Julio Delgado
- Hospital Clínic, Department of Haematology Calle Villarroel, 170 08036 Barcelona, Spain
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18
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Baba Y, Kurosaki T. Role of Calcium Signaling in B Cell Activation and Biology. Curr Top Microbiol Immunol 2015; 393:143-174. [PMID: 26369772 DOI: 10.1007/82_2015_477] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Increase in intracellular levels of calcium ions (Ca2+) is one of the key triggering signals for the development of B cell response to the antigen. The diverse Ca2+ signals finely controlled by multiple factors participate in the regulation of gene expression, B cell development, and effector functions. B cell receptor (BCR)-initiated Ca2+ mobilization is sourced from two pathways: one is the release of Ca2+ from the intracellular stores, endoplasmic reticulum (ER), and other is the prolonged influx of extracellular Ca2+ induced by depleting the stores via store-operated calcium entry (SOCE) and calcium release-activated calcium (CRAC) channels. The identification of stromal interaction molecule 1(STIM1), the ER Ca2+ sensor, and Orai1, a key subunit of the CRAC channel pore, has now provided the tools to understand the mode of Ca2+ influx regulation and physiological relevance. Herein, we discuss our current understanding of the molecular mechanisms underlying BCR-triggered Ca2+ signaling as well as its contribution to the B cell biological processes and diseases.
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Affiliation(s)
- Yoshihiro Baba
- Laboratory for Lymphocyte Differentiation, WPI Immunology Frontier Research Center (IFReC), Osaka University, Suita, Osaka, 565-0871, Japan. .,Laboratory for Lymphocyte Differentiation, RIKEN Center for Integrative Medical Sciences (IMS), Kanagawa, Yokohama, 230-0045, Japan.
| | - Tomohiro Kurosaki
- Laboratory for Lymphocyte Differentiation, WPI Immunology Frontier Research Center (IFReC), Osaka University, Suita, Osaka, 565-0871, Japan.,Laboratory for Lymphocyte Differentiation, RIKEN Center for Integrative Medical Sciences (IMS), Kanagawa, Yokohama, 230-0045, Japan
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19
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Han Y, Liu X, Yu T, Shi B, Xiao R, Pang Y, Li Q. A novel member of B-cell linker protein identified in lamprey, Lampetra japonica. Acta Biochim Biophys Sin (Shanghai) 2014; 46:526-30. [PMID: 24785332 DOI: 10.1093/abbs/gmu027] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Affiliation(s)
- Yinglun Han
- College of Life Science, Liaoning Normal University, Dalian 116029, China Lamprey Research Center, Liaoning Normal University, Dalian 116029, China
| | - Xin Liu
- College of Life Science, Liaoning Normal University, Dalian 116029, China Lamprey Research Center, Liaoning Normal University, Dalian 116029, China
| | - Tao Yu
- College of Life Science, Liaoning Normal University, Dalian 116029, China Lamprey Research Center, Liaoning Normal University, Dalian 116029, China
| | - Biyue Shi
- College of Life Science, Liaoning Normal University, Dalian 116029, China Lamprey Research Center, Liaoning Normal University, Dalian 116029, China
| | - Rong Xiao
- College of Life Science, Liaoning Normal University, Dalian 116029, China Lamprey Research Center, Liaoning Normal University, Dalian 116029, China
| | - Yue Pang
- College of Life Science, Liaoning Normal University, Dalian 116029, China Lamprey Research Center, Liaoning Normal University, Dalian 116029, China
| | - Qingwei Li
- College of Life Science, Liaoning Normal University, Dalian 116029, China Lamprey Research Center, Liaoning Normal University, Dalian 116029, China
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20
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Wu H, Wang W, Liu F, Weisberg EL, Tian B, Chen Y, Li B, Wang A, Wang B, Zhao Z, McMillin DW, Hu C, Li H, Wang J, Liang Y, Buhrlage SJ, Liang J, Liu J, Yang G, Brown JR, Treon SP, Mitsiades CS, Griffin JD, Liu Q, Gray NS. Discovery of a potent, covalent BTK inhibitor for B-cell lymphoma. ACS Chem Biol 2014; 9:1086-91. [PMID: 24556163 PMCID: PMC4027949 DOI: 10.1021/cb4008524] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
BTK is a member of the TEC family of non-receptor tyrosine kinases whose deregulation has been implicated in a variety of B-cell-related diseases. We have used structure-based drug design in conjunction with kinome profiling and cellular assays to develop a potent, selective, and irreversible BTK kinase inhibitor, QL47, which covalently modifies Cys481. QL47 inhibits BTK kinase activity with an IC50 of 7 nM, inhibits autophosphorylation of BTK on Tyr223 in cells with an EC50 of 475 nM, and inhibits phosphorylation of a downstream effector PLCγ2 (Tyr759) with an EC50 of 318 nM. In Ramos cells QL47 induces a G1 cell cycle arrest that is associated with pronounced degradation of BTK protein. QL47 inhibits the proliferation of B-cell lymphoma cancer cell lines at submicromolar concentrations.
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Affiliation(s)
- Hong Wu
- High
Magnetic Field laboratory, Chinese Academy of Sciences, Mailbox
1110, 350 Shushanhu Road, Hefei 230031, Anhui, P. R. China
- University of Science and Technology of China, Hefei 230036, Anhui, P. R. China
| | - Wenchao Wang
- High
Magnetic Field laboratory, Chinese Academy of Sciences, Mailbox
1110, 350 Shushanhu Road, Hefei 230031, Anhui, P. R. China
| | - Feiyang Liu
- High
Magnetic Field laboratory, Chinese Academy of Sciences, Mailbox
1110, 350 Shushanhu Road, Hefei 230031, Anhui, P. R. China
- University of Science and Technology of China, Hefei 230036, Anhui, P. R. China
| | - Ellen L. Weisberg
- Department
of Medical Oncology, Dana−Farber Cancer Institute, Harvard Medical School, 450 Brookline Avenue, Boston, Massachusetts 02115, United States
| | - Bei Tian
- Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University; Beijing Ophthalmology & Visual Science Key Laboratory, Beijing 100730, P. R. China
| | - Yongfei Chen
- High
Magnetic Field laboratory, Chinese Academy of Sciences, Mailbox
1110, 350 Shushanhu Road, Hefei 230031, Anhui, P. R. China
| | - Binhua Li
- High
Magnetic Field laboratory, Chinese Academy of Sciences, Mailbox
1110, 350 Shushanhu Road, Hefei 230031, Anhui, P. R. China
| | - Aoli Wang
- High
Magnetic Field laboratory, Chinese Academy of Sciences, Mailbox
1110, 350 Shushanhu Road, Hefei 230031, Anhui, P. R. China
| | - Beilei Wang
- High
Magnetic Field laboratory, Chinese Academy of Sciences, Mailbox
1110, 350 Shushanhu Road, Hefei 230031, Anhui, P. R. China
| | - Zheng Zhao
- High
Magnetic Field laboratory, Chinese Academy of Sciences, Mailbox
1110, 350 Shushanhu Road, Hefei 230031, Anhui, P. R. China
| | - Douglas W. McMillin
- Department
of Medical Oncology, Dana−Farber Cancer Institute, Harvard Medical School, 450 Brookline Avenue, Boston, Massachusetts 02115, United States
| | - Chen Hu
- High
Magnetic Field laboratory, Chinese Academy of Sciences, Mailbox
1110, 350 Shushanhu Road, Hefei 230031, Anhui, P. R. China
| | - Hong Li
- High
Magnetic Field laboratory, Chinese Academy of Sciences, Mailbox
1110, 350 Shushanhu Road, Hefei 230031, Anhui, P. R. China
| | - Jinhua Wang
- Department of Biological Chemistry & Molecular Pharmacology, Harvard Medical School, 250 Longwood Avenue, SGM 628, Boston, Massachusetts 02115, United States
| | - Yanke Liang
- Department of Biological Chemistry & Molecular Pharmacology, Harvard Medical School, 250 Longwood Avenue, SGM 628, Boston, Massachusetts 02115, United States
| | - Sara J. Buhrlage
- Department of Biological Chemistry & Molecular Pharmacology, Harvard Medical School, 250 Longwood Avenue, SGM 628, Boston, Massachusetts 02115, United States
| | - Junting Liang
- Key
Laboratory of Ion Beam Bioengineering, Hefei Institutes of Physical
Science, Chinese Academy of Sciences, 350 Shushanhu Road, Hefei 230031, Anhui, P. R. China
| | - Jing Liu
- High
Magnetic Field laboratory, Chinese Academy of Sciences, Mailbox
1110, 350 Shushanhu Road, Hefei 230031, Anhui, P. R. China
| | - Guang Yang
- Department
of Medical Oncology, Dana−Farber Cancer Institute, Harvard Medical School, 450 Brookline Avenue, Boston, Massachusetts 02115, United States
- Bing Center
for Waldenström’s Macroglobulinemia, Dana−Farber Cancer Institute, M547, 450 Brookline Avenue, Boston, Massachusetts 02115, United States
| | - Jennifer R. Brown
- Department
of Medical Oncology, Dana−Farber Cancer Institute, Harvard Medical School, 450 Brookline Avenue, Boston, Massachusetts 02115, United States
| | - Steven P. Treon
- Department
of Medical Oncology, Dana−Farber Cancer Institute, Harvard Medical School, 450 Brookline Avenue, Boston, Massachusetts 02115, United States
- Bing Center
for Waldenström’s Macroglobulinemia, Dana−Farber Cancer Institute, M547, 450 Brookline Avenue, Boston, Massachusetts 02115, United States
| | - Constantine S. Mitsiades
- Department
of Medical Oncology, Dana−Farber Cancer Institute, Harvard Medical School, 450 Brookline Avenue, Boston, Massachusetts 02115, United States
| | - James D. Griffin
- Department
of Medical Oncology, Dana−Farber Cancer Institute, Harvard Medical School, 450 Brookline Avenue, Boston, Massachusetts 02115, United States
| | - Qingsong Liu
- High
Magnetic Field laboratory, Chinese Academy of Sciences, Mailbox
1110, 350 Shushanhu Road, Hefei 230031, Anhui, P. R. China
- University of Science and Technology of China, Hefei 230036, Anhui, P. R. China
| | - Nathanael S. Gray
- Department of Biological Chemistry & Molecular Pharmacology, Harvard Medical School, 250 Longwood Avenue, SGM 628, Boston, Massachusetts 02115, United States
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21
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Engelke M, Oellerich T, Dittmann K, Hsiao HH, Urlaub H, Serve H, Griesinger C, Wienands J. Cutting Edge: Feed-Forward Activation of Phospholipase Cγ2 via C2 Domain–Mediated Binding to SLP65. THE JOURNAL OF IMMUNOLOGY 2013; 191:5354-8. [DOI: 10.4049/jimmunol.1301326] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
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22
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Arita A, McFarland DC, Myklebust JH, Parekh S, Petersen B, Gabrilove J, Brody JD. Signaling pathways in lymphoma: pathogenesis and therapeutic targets. Future Oncol 2013; 9:1549-71. [DOI: 10.2217/fon.13.113] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Lymphoma is the fifth most common cancer in the USA. Most lymphomas are classified as non-Hodgkin’s lymphoma, and nearly 95% of these cancers are of B-cell origin. B-cell receptor (BCR) surface expression and BCR functional signaling are critical for survival and proliferation of both healthy B cells, as well as most B-lymphoma cells. Agents that inhibit various components of the BCR signaling pathway, as well as parallel signaling pathways, are currently in clinical trials for the treatment of various lymphoma subtypes, including those targeting isoforms of PI3K, mTOR and BTK. In this review, we describe the signaling pathways in healthy mature B cells, the aberrant signaling in lymphomatous B cells and the rationale for clinical trials of agents targeting these pathways as well as the results of clinical trials to date. We propose that the entry into a kinase inhibitor era of lymphoma therapy will be as transformative for our patients as the advent of the antibody or chemotherapy era before it.
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Affiliation(s)
- Adriana Arita
- Division of Hematology/Oncology, Tisch Cancer Institute & Department of Medicine, Mount Sinai School of Medicine, New York, NY 10029, USA
| | - Daniel C McFarland
- Division of Hematology/Oncology, Tisch Cancer Institute & Department of Medicine, Mount Sinai School of Medicine, New York, NY 10029, USA
| | - June H Myklebust
- Department of Immunology, Institute for Cancer Research, Oslo University Hospital/Centre for Cancer Biomedicine, University of Oslo, Oslo, Norway
| | - Samir Parekh
- Division of Hematology/Oncology, Tisch Cancer Institute & Department of Medicine, Mount Sinai School of Medicine, New York, NY 10029, USA
| | - Bruce Petersen
- Department of Pathology, Mount Sinai School of Medicine, New York, NY 10029, USA
| | - Janice Gabrilove
- Division of Hematology/Oncology, Tisch Cancer Institute & Department of Medicine, Mount Sinai School of Medicine, New York, NY 10029, USA
| | - Joshua D Brody
- Division of Hematology/Oncology, Tisch Cancer Institute & Department of Medicine, Mount Sinai School of Medicine, New York, NY 10029, USA
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23
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Brewer JW. Phospholipids: "greasing the wheels" of humoral immunity. BIOCHIMICA ET BIOPHYSICA ACTA 2013; 1831:642-51. [PMID: 23051607 PMCID: PMC3562403 DOI: 10.1016/j.bbalip.2012.09.018] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/01/2012] [Revised: 09/27/2012] [Accepted: 09/28/2012] [Indexed: 12/14/2022]
Abstract
Phospholipids are major structural components of all cellular membranes. In addition, certain phospholipids execute regulatory activities that affect cell behavior, function and fate in critically important physiological settings. The influence of phospholipids is especially obvious in the adaptive immune system, where these macromolecules mediate both intrinsic and extrinsic effects on B and T lymphocytes. This review article highlights the action of lysophospholipid sphingosine-1-phosphate as a lymphocyte chemoattractant, the function of phosphatidylinositol phosphates as signaling conduits in lymphocytes and the role of phospholipids as raw materials for membrane assembly and organelle biogenesis in activated B lymphocytes. Special emphasis is placed on the means by which these three processes push humoral immune responses forward. This article is part of a Special Issue entitled Phospholipids and Phospholipid Metabolism.
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Affiliation(s)
- Joseph W Brewer
- Department of Microbiology and Immunology, College of Medicine, University of South Alabama, 5851 USA Drive North Mobile, AL 36688, USA.
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24
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Maus M, Medgyesi D, Kiss E, Schneider AE, Enyedi A, Szilágyi N, Matkó J, Sármay G. B cell receptor-induced Ca2+ mobilization mediates F-actin rearrangements and is indispensable for adhesion and spreading of B lymphocytes. J Leukoc Biol 2013; 93:537-47. [PMID: 23362305 DOI: 10.1189/jlb.0312169] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
B cells acquire membrane-bound cognate antigens from the surface of the APCs by forming an IS, similar to that seen in T cells. Recognition of membrane-bound antigens on the APCs initiates adhesion of B lymphocytes to the antigen-tethered surface, which is followed by the formation of radial lamellipodia-like structures, a process known as B cell spreading. The spreading response requires the rearrangement of the submembrane actin cytoskeleton and is regulated mainly via signals transmitted by the BCR. Here, we show that cytoplasmic calcium is a regulator of actin cytoskeleton dynamics in B lymphocytes. We find that BCR-induced calcium mobilization is indispensible for adhesion and spreading of B cells and that PLCγ and CRAC-mediated calcium mobilization are critical regulators of these processes. Measuring calcium and actin dynamics in live cells, we found that a generation of actin-based membrane protrusion is strongly linked to the dynamics of a cytoplasmic-free calcium level. Finally, we demonstrate that PLCγ and CRAC channels regulate the activity of actin-severing protein cofilin, linking BCR-induced calcium signaling to the actin dynamics.
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Affiliation(s)
- Máté Maus
- Eötvös Lóránd University, Pázmány Péter sétány 1/c, Budapest, Hungary
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Lösing M, Goldbeck I, Manno B, Oellerich T, Schnyder T, Bohnenberger H, Stork B, Urlaub H, Batista FD, Wienands J, Engelke M. The Dok-3/Grb2 protein signal module attenuates Lyn kinase-dependent activation of Syk kinase in B cell antigen receptor microclusters. J Biol Chem 2013; 288:2303-13. [PMID: 23223229 PMCID: PMC3554902 DOI: 10.1074/jbc.m112.406546] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2012] [Revised: 11/20/2012] [Indexed: 02/02/2023] Open
Abstract
Recruitment of the growth factor receptor-bound protein 2 (Grb2) by the plasma membrane-associated adapter protein downstream of kinase 3 (Dok-3) attenuates signals transduced by the B cell antigen receptor (BCR). Here we describe molecular details of Dok-3/Grb2 signal integration and function, showing that the Lyn-dependent activation of the BCR transducer kinase Syk is attenuated by Dok-3/Grb2 in a site-specific manner. This process is associated with the SH3 domain-dependent translocation of Dok-3/Grb2 complexes into BCR microsignalosomes and augmented phosphorylation of the inhibitory Lyn target SH2 domain-containing inositol 5' phosphatase. Hence, our findings imply that Dok-3/Grb2 modulates the balance between activatory and inhibitory Lyn functions with the aim to adjust BCR signaling efficiency.
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Affiliation(s)
- Marion Lösing
- Georg August University of Göttingen, Institute of Cellular and Molecular Immunology, Humboldtallee 34, 37073 Göttingen, Germany
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Bicocca VT, Chang BH, Masouleh BK, Muschen M, Loriaux MM, Druker BJ, Tyner JW. Crosstalk between ROR1 and the Pre-B cell receptor promotes survival of t(1;19) acute lymphoblastic leukemia. Cancer Cell 2012; 22:656-67. [PMID: 23153538 PMCID: PMC3500515 DOI: 10.1016/j.ccr.2012.08.027] [Citation(s) in RCA: 129] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/06/2011] [Revised: 03/22/2012] [Accepted: 08/28/2012] [Indexed: 12/21/2022]
Abstract
We report that t(1;19) ALL cells universally exhibit expression of and dependence on the cell surface receptor ROR1. We further identify t(1;19) ALL cell sensitivity to the kinase inhibitor dasatinib due to its inhibition of the pre-B cell receptor (pre-BCR) signaling complex. These phenotypes are a consequence of developmental arrest at an intermediate/late stage of B-lineage maturation. Additionally, inhibition of pre-BCR signaling induces further ROR1 upregulation, and we identify distinct ROR1 and pre-BCR downstream signaling pathways that are modulated in a counterbalancing manner-both leading to AKT phosphorylation. Consistent with this, AKT phosphorylation is transiently eliminated after dasatinib treatment, but is partially restored following dasatinib potentiation of ROR1 expression. Consequently, ROR1 silencing accentuates dasatinib killing of t(1;19) ALL cells.
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Affiliation(s)
- Vincent T Bicocca
- Division of Hematology and Medical Oncology, Oregon Health & Science University, Portland, OR 97239, USA.
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27
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Block H, Zarbock A. The role of the tec kinase Bruton's tyrosine kinase (Btk) in leukocyte recruitment. Int Rev Immunol 2012; 31:104-18. [PMID: 22449072 DOI: 10.3109/08830185.2012.668982] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Recruitment of leukocytes into inflamed tissue is a key component of the immune system. The activation of integrins on leukocytes is required for their recruitment into the inflamed tissue. Btk is a cytoplasmic nonreceptor tyrosine kinase belonging to the Tec-kinase family. It plays a key role in B-cell development and function, and recently published studies revealed important roles of Btk in myeloid cells. Btk might be activated through a variety of receptors leading to activation of integrins as the pivotal element in leukocyte recruitment. This review focuses on the role of Btk in B-lymphocyte homing and in neutrophil recruitment.
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Affiliation(s)
- Helena Block
- Department of Anesthesiology and Critical Care Medicine, University of Muenster, Muenster, Germany
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28
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Abstract
Targeted therapy with imatinib and other selective tyrosine kinase inhibitors has transformed the treatment of chronic myeloid leukemia. Unlike chronic myeloid leukemia, chronic lymphocytic leukemia (CLL) lacks a common genetic aberration amenable to therapeutic targeting. However, our understanding of normal B-cell versus CLL biology points to differences in properties of B-cell receptor (BCR) signaling that may be amenable to selective therapeutic targeting. The application of mouse models has further expanded this understanding and provides information about targets in the BCR signaling pathway that may have other important functions in cell development or long-term health. In addition, overexpression or knockout of selected targets offers the potential to validate targets genetically using new mouse models of CLL. The initial success of BCR-targeted therapies has promoted much excitement in the field of CLL. At the present time, GS-1101, which reversibly inhibits PI3Kδ, and ibrutinib (PCI-32765), an irreversible inhibitor of Bruton tyrosine kinase, have generated the most promising early results in clinical trials including predominately refractory CLL where durable disease control has been observed. This review provides a summary of BCR signaling, tools for studying this pathway relevant to drug development in CLL, and early progress made with therapeutics targeting BCR-related kinases.
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Junek S, Engelke M, Schild D, Wienands J. Spatiotemporal resolution of Ca2+signaling events by real time imaging of single B cells. FEBS Lett 2012; 586:1452-8. [DOI: 10.1016/j.febslet.2012.03.057] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2011] [Revised: 03/13/2012] [Accepted: 03/27/2012] [Indexed: 10/28/2022]
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Balakrishnan K, Gandhi V. Protein kinases: emerging therapeutic targets in chronic lymphocytic leukemia. Expert Opin Investig Drugs 2012; 21:409-23. [PMID: 22409342 DOI: 10.1517/13543784.2012.668526] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
INTRODUCTION Although protein kinases are primary targets for inhibition in hematological malignancies, until recently their contribution to chronic lymphocytic leukemia (CLL) was poorly understood. Insights into B-cell receptor signaling and its role in regulating key cellular functions have shed light on candidate protein kinases that are aberrantly activated in CLL. In this regard, protein kinases are now considered as potential drug targets in CLL. AREA COVERED This review has covered signaling pathways and associated protein kinases in CLL and the kinase inhibitors currently available in preclinical and clinical investigations. Individual protein kinases that are abnormally active in CLL and the functional consequences of their inhibition are discussed. EXPERT OPINION A growing body of evidence suggests that protein kinases are druggable targets for patients with CLL. The emergence of novel and bio-available kinase inhibitors and their promising clinical activity in CLL underscore the oncogenic role of kinases in leukemogenesis. Further investigations directed towards their role as single agents or in combinations may provide insight into understanding the substantial role of kinase-mediated signal transduction pathways and their inhibition in B- CLL.
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Affiliation(s)
- Kumudha Balakrishnan
- The University of Texas MD Anderson Cancer Center, Department of Experimental Therapeutics, Houston, TX 77030, USA.
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The B-cell antigen receptor signals through a preformed transducer module of SLP65 and CIN85. EMBO J 2011; 30:3620-34. [PMID: 21822214 PMCID: PMC3181483 DOI: 10.1038/emboj.2011.251] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2011] [Accepted: 07/05/2011] [Indexed: 12/27/2022] Open
Abstract
Spleen tyrosine kinase Syk and its substrate SLP65 (also called BLNK) are proximal signal transducer elements of the B-cell antigen receptor (BCR). Yet, our understanding of signal initiation and processing is limited owing to the incomplete list of SLP65 interaction partners and our ignorance of their association kinetics. We have now determined and quantified the in vivo interactomes of SLP65 in resting and stimulated B cells by mass spectrometry. SLP65 orchestrated a complex signal network of about 30 proteins that was predominantly based on dynamic interactions. However, a stimulation-independent and constant association of SLP65 with the Cbl-interacting protein of 85 kDa (CIN85) was requisite for SLP65 phosphorylation and its inducible plasma membrane translocation. In the absence of a steady SLP65/CIN85 complex, BCR-induced Ca(2+) and NF-κB responses were abrogated. Finally, live cell imaging and co-immunoprecipitation experiments further confirmed that both SLP65 and CIN85 are key components of the BCR-associated primary transducer module required for the onset and progression phases of BCR signal transduction.
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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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Abstract
The inhibitor of Bruton tyrosine kinase γ (IBtkγ) is a negative regulator of the Bruton tyrosine kinase (Btk), which plays a major role in B-cell differentiation; however, the mechanisms of IBtkγ-mediated regulation of Btk are unknown. Here we report that B-cell receptor (BCR) triggering caused serine-phosphorylation of IBtkγ at protein kinase C consensus sites and dissociation from Btk. By liquid chromatography and mass-mass spectrometry and functional analysis, we identified IBtkγ-S87 and -S90 as the critical amino acid residues that regulate the IBtkγ binding affinity to Btk. Consistently, the mutants IBtkγ carrying S87A and S90A mutations bound constitutively to Btk and down-regulated Ca(2+) fluxes and NF-κB activation on BCR triggering. Accordingly, spleen B cells from Ibtkγ(-/-) mice showed an increased activation of Btk, as evaluated by Y551-phosphorylation and sustained Ca(2+) mobilization on BCR engagement. These findings identify a novel pathway of Btk regulation via protein kinase C phosphorylation of IBtkγ.
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Pechloff K, Holch J, Ferch U, Schweneker M, Brunner K, Kremer M, Sparwasser T, Quintanilla-Martinez L, Zimber-Strobl U, Streubel B, Gewies A, Peschel C, Ruland J. The fusion kinase ITK-SYK mimics a T cell receptor signal and drives oncogenesis in conditional mouse models of peripheral T cell lymphoma. ACTA ACUST UNITED AC 2010; 207:1031-44. [PMID: 20439541 PMCID: PMC2867290 DOI: 10.1084/jem.20092042] [Citation(s) in RCA: 114] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Peripheral T cell lymphomas (PTCLs) are highly aggressive malignancies with poor prognosis. Their molecular pathogenesis is not well understood and small animal models for the disease are lacking. Recently, the chromosomal translocation t(5;9)(q33;q22) generating the interleukin-2 (IL-2)–inducible T cell kinase (ITK)–spleen tyrosine kinase (SYK) fusion tyrosine kinase was identified as a recurrent event in PTCL. We show that ITK-SYK associates constitutively with lipid rafts in T cells and triggers antigen-independent phosphorylation of T cell receptor (TCR)–proximal proteins. These events lead to activation of downstream pathways and acute cellular outcomes that correspond to regular TCR ligation, including up-regulation of CD69 or production of IL-2 in vitro or deletion of thymocytes and activation of peripheral T cells in vivo. Ultimately, conditional expression of patient-derived ITK-SYK in mice induces highly malignant PTCLs with 100% penetrance that resemble the human disease. Our work demonstrates that constitutively enforced antigen receptor signaling can, in principle, act as a powerful oncogenic driver. Moreover, we establish a robust clinically relevant and genetically tractable model of human PTCL.
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Affiliation(s)
- Konstanze Pechloff
- Third Medical Department, Technical University of Munich, Klinikum rechts der Isar, 81675 Munich, Germany
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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: 178] [Impact Index Per Article: 12.7] [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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36
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Lin L, Czerwinski R, Kelleher K, Siegel MM, Wu P, Kriz R, Aulabaugh A, Stahl M. Activation loop phosphorylation modulates Bruton's tyrosine kinase (Btk) kinase domain activity. Biochemistry 2009; 48:2021-32. [PMID: 19206206 DOI: 10.1021/bi8019756] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Bruton's tyrosine kinase (Btk) plays a central role in signal transduction pathways regulating survival, activation, proliferation, and differentiation of B-lineage lymphoid cells. A number of cell signaling studies clearly show that Btk is activated by Lyn, a Src family kinase, through phosphorylation on activation loop tyrosine 551 (Y(551)). However, the detailed molecular mechanism regulating Btk activation remains unclear. In particular, we do not fully understand the correlation of kinase activity with Y(551) phosphorylation, and the role of the noncatalytic domains of Btk in the activation process. Insect cell expressed full-length Btk is enzymatically active, but a truncated version of Btk, composed of only the kinase catalytic domain, is largely inactive. Further characterization of both forms of Btk by mass spectrometry showed partial phosphorylation of Y(551) of the full-length enzyme and none of the truncated kinase domain. To determine whether the lack of activity of the kinase domain was due to the absence of Y(551) phosphorylation, we developed an in vitro method to generate Y(551) monophosphorylated Btk kinase domain fragment using the Src family kinase Lyn. Detailed kinetic analyses demonstrated that the in vitro phosphorylated Btk kinase domain has a similar activity as the full-length enzyme while the unphosphorylated kinase domain has a very low k(cat) and is largely inactive. A divalent magnesium metal dependence study established that Btk requires a second magnesium ion for activity. Furthermore, our analysis revealed significant differences in the second metal-binding site among the kinase domain and the full-length enzyme that likely account for the difference in their catalytic profile. Taken together, our study provides important mechanistic insights into Btk kinase activity and phosphorylation-mediated regulation.
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Affiliation(s)
- Laura Lin
- Structural Biology and Computational Chemistry, Wyeth Research, 200 Cambridge Park Drive, Cambridge, Massachusetts 02140, USA.
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37
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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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38
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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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Mohamed AJ, Yu L, Bäckesjö CM, Vargas L, Faryal R, Aints A, Christensson B, Berglöf A, Vihinen M, Nore BF, Smith CIE. Bruton's tyrosine kinase (Btk): function, regulation, and transformation with special emphasis on the PH domain. Immunol Rev 2009; 228:58-73. [PMID: 19290921 DOI: 10.1111/j.1600-065x.2008.00741.x] [Citation(s) in RCA: 358] [Impact Index Per Article: 23.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Bruton's agammaglobulinemia tyrosine kinase (Btk) is a cytoplasmic tyrosine kinase important in B-lymphocyte development, differentiation, and signaling. Btk is a member of the Tec family of kinases. Mutations in the Btk gene lead to X-linked agammaglobulinemia (XLA) in humans and X-linked immunodeficiency (Xid) in mice. Activation of Btk triggers a cascade of signaling events that culminates in the generation of calcium mobilization and fluxes, cytoskeletal rearrangements, and transcriptional regulation involving nuclear factor-kappaB (NF-kappaB) and nuclear factor of activated T cells (NFAT). In B cells, NF-kappaB was shown to bind to the Btk promoter and induce transcription, whereas the B-cell receptor-dependent NF-kappaB signaling pathway requires functional Btk. Moreover, Btk activation is tightly regulated by a plethora of other signaling proteins including protein kinase C (PKC), Sab/SH3BP5, and caveolin-1. For example, the prolyl isomerase Pin1 negatively regulates Btk by decreasing tyrosine phosphorylation and steady state levels of Btk. It is intriguing that PKC and Pin1, both of which are negative regulators, bind to the pleckstrin homology domain of Btk. To this end, we describe here novel mutations in the pleckstrin homology domain investigated for their transforming capacity. In particular, we show that the mutant D43R behaves similar to E41K, already known to possess such activity.
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Affiliation(s)
- Abdalla J Mohamed
- Clinical Research Center, Department of Laboratory Medicine, Karolinska Institutet, Huddinge University Hospital, Huddinge, Sweden
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Vendel AC, Calemine-Fenaux J, Izrael-Tomasevic A, Chauhan V, Arnott D, Eaton DL. B and T lymphocyte attenuator regulates B cell receptor signaling by targeting Syk and BLNK. THE JOURNAL OF IMMUNOLOGY 2009; 182:1509-17. [PMID: 19155498 DOI: 10.4049/jimmunol.182.3.1509] [Citation(s) in RCA: 83] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
B and T lymphocyte attenuator (BTLA) functions as a negative regulator of T cell activation and proliferation. Although the role of BTLA in regulating T cell responses has been characterized, a thorough investigation into the precise molecular mechanisms involved in BTLA-mediated lymphocyte attenuation and, more specifically, its role in regulating B cell activation has not been presented. In this study, we have begun to elucidate the biochemical mechanisms by which BTLA functions to inhibit B cell activation. We describe the cell surface expression of BTLA on various human B cell subsets and confirm its ability to attenuate B cell proliferation upon associating with its known ligand, herpesvirus entry mediator (HVEM). BTLA associates with the BCR and, upon binding to HVEM, recruits the tyrosine phosphatase Src homology 2 domain-containing phosphatase 1 and reduces activation of signaling molecules downstream of the BCR. This is exemplified by a quantifiable decrease in tyrosine phosphorylation of the protein tyrosine kinase Syk, as measured by absolute quantification mass spectrometry. Furthermore, effector molecules downstream of BCR signaling, including the B cell linker protein, phospholipase Cgamma2, and NF-kappaB, display decreased activation and nuclear translocation, respectively, after BTLA activation by HVEM. These results begin to provide insight into the mechanism by which BTLA negatively regulates B cell activation and indicates that BTLA is an inhibitory coreceptor of the BCR signaling pathway and attenuates B cell activation by targeting the downstream signaling molecules Syk and B cell linker protein.
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Affiliation(s)
- Andrew C Vendel
- Department of Protein Chemistry, Genentech, Inc., South San Francisco, CA 94080, USA
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41
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Geahlen RL. Syk and pTyr'd: Signaling through the B cell antigen receptor. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2009; 1793:1115-27. [PMID: 19306898 DOI: 10.1016/j.bbamcr.2009.03.004] [Citation(s) in RCA: 120] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/17/2009] [Accepted: 03/06/2009] [Indexed: 11/18/2022]
Abstract
The B cell receptor (BCR) transduces antigen binding into alterations in the activity of intracellular signaling pathways through its ability to recruit and activate the cytoplasmic protein-tyrosine kinase Syk. The recruitment of Syk to the receptor, its activation and its subsequent interactions with downstream effectors are all regulated by its phosphorylation on tyrosine. This review discusses our current understanding of how this phosphorylation regulates the activity of Syk and its participation in signaling through the BCR.
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Affiliation(s)
- Robert L Geahlen
- Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, West Lafayette, IN 47907, USA.
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Antigen-specific B-1a antibodies induced by Francisella tularensis LPS provide long-term protection against F. tularensis LVS challenge. Proc Natl Acad Sci U S A 2009; 106:4343-8. [PMID: 19251656 DOI: 10.1073/pnas.0813411106] [Citation(s) in RCA: 93] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Francisella tularensis (Ft), a gram-negative intracellular bacterium, is the etiologic agent of tularemia. Infection of mice with <10 Ft Live Vaccine Strain (Ft LVS) organisms i.p. causes a lethal infection that resembles human tularemia. Here, we show that immunization with as little as 0.1 ng Ft LVS lipopolysaccharide (Ft-LPS), but not Ft lipid A, generates a rapid antibody response that protects wild-type (WT) mice against lethal Ft LVS challenge. Protection is not induced in Ft-LPS-immunized B cell-deficient mice (muMT or JhD), male xid mice, or Ig transgenic mice that produce a single IgH (not reactive with Ft-LPS). Focusing on the cellular mechanisms that underlie this protective response, we show that Ft-LPS specifically stimulates proliferation of B-1a lymphocytes that bind fluorochrome-labeled Ft-LPS and the differentiation of these cells to plasma cells that secrete antibodies specific for Ft-LPS. This exclusively B-1a antibody response is equivalent in WT, T-deficient (TCRalphabeta(-/-), TCRgammadelta(-/-)), and Toll-like receptor 4 (TLR4)-deficient (TLR4(-/-)) mice and thus is not dependent on T cells or typical inflammatory processes. Serum antibody levels peak approximately 5 days after Ft-LPS immunization and persist at low levels for months. Thus, immunization with Ft-LPS activates a rare population of antigen-specific B-1a cells to produce a persistent T-independent antibody response that provides long-term protection against lethal Ft LVS infection. These data support the possibility of creating effective, minimally invasive vaccines that can provide effective protection against pathogen invasion.
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Arana E, Harwood NE, Batista FD. Regulation of integrin activation through the B-cell receptor. J Cell Sci 2008; 121:2279-86. [PMID: 18596256 DOI: 10.1242/jcs.017905] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Effective immune surveillance is absolutely dependent on the migration of lymphocytes throughout the body and on their successful recognition of specific antigens. Both of these functions rely on the capacity of integrins that are expressed on the surface of lymphocytes to respond in a highly regulated manner to a variety of chemokines and antigens. This Commentary is primarily concerned with the role of the B-cell integrins LFA-1 and VLA-4 in the antigen-recognition process, and summarises what is currently known about the molecular mechanisms of ;inside-out' integrin activation in response to B-cell-receptor stimulation. Recent investigations have identified Vav, PI3K and small GTPases as crucial regulators of the inside-out activation of B-cell integrins. These observations are of particular interest as they allude to an underlying mechanism by which B-cell-receptor-mediated signalling is linked to cytoskeleton reorganisation and subsequent integrin activation.
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Affiliation(s)
- Eloisa Arana
- Lymphocyte Interaction Laboratory, Cancer Research UK London Research Institute, Lincoln's Inn Fields Laboratories, London WC2A 3PX, UK
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Identification of FcgammaRIIa as the ITAM-bearing receptor mediating alphaIIbbeta3 outside-in integrin signaling in human platelets. Blood 2008; 112:2780-6. [PMID: 18641368 DOI: 10.1182/blood-2008-02-142125] [Citation(s) in RCA: 141] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Immunoreceptor tyrosine-based activation motif (ITAM)-containing proteins have recently been demonstrated in macrophages and neutrophils to be required for cell surface integrins to transmit activation signals into the cell. To identify ITAM-bearing proteins that mediate signaling via the platelet-specific integrin alphaIIbbeta3, fibrinogen binding was induced by (1) allowing platelets to spread directly on immobilized fibrinogen, or (2) activating the PAR1 thrombin receptor on platelets in suspension. Both initiated strong, ligand binding-dependent tyrosine phosphorylation of the ITAM-bearing platelet Fc receptor, FcgammaRIIa, as well as downstream phosphorylation of the protein tyrosine kinase Syk and activation of phospholipase Cgamma2 (PLCgamma2). Addition of Fab fragments of an FcgammaRIIa-specific monoclonal antibody strongly inhibited platelet spreading on immobilized fibrinogen, as well as downstream tyrosine phosphorylation of FcgammaRIIa, Syk, and PLCgamma2, and platelets from a patient whose platelets express reduced levels of FcgammaRIIa exhibited markedly reduced spreading on immobilized fibrinogen. Finally, fibrinogen binding-induced FcgammaRIIa phosphorylation did not occur in human platelets expressing a truncated beta3 cytoplasmic domain. Taken together, these data suggest that ligand binding to platelet alphaIIbbeta3 induces integrin cytoplasmic domain-dependent phosphorylation of FcgammaRIIa, which then enlists selected components of the immunoreceptor signaling cascade to transmit amplification signals into the cell.
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Shinohara M, Koga T, Okamoto K, Sakaguchi S, Arai K, Yasuda H, Takai T, Kodama T, Morio T, Geha RS, Kitamura D, Kurosaki T, Ellmeier W, Takayanagi H. Tyrosine kinases Btk and Tec regulate osteoclast differentiation by linking RANK and ITAM signals. Cell 2008; 132:794-806. [PMID: 18329366 DOI: 10.1016/j.cell.2007.12.037] [Citation(s) in RCA: 238] [Impact Index Per Article: 14.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2007] [Revised: 11/08/2007] [Accepted: 12/27/2007] [Indexed: 12/24/2022]
Abstract
Certain autoimmune diseases result in abnormal bone homeostasis, but association of immunodeficiency with bone is poorly understood. Osteoclasts, which derive from bone marrow cells, are under the control of the immune system. Differentiation of osteoclasts is mainly regulated by signaling pathways activated by RANK and immune receptors linked to ITAM-harboring adaptors. However, it is unclear how the two signals merge to cooperate in osteoclast differentiation. Here we report that mice lacking the tyrosine kinases Btk and Tec show severe osteopetrosis caused by a defect in bone resorption. RANK and ITAM signaling results in formation of a Btk(Tec)/BLNK(SLP-76)-containing complex and PLCgamma-mediated activation of an essential calcium signal. Furthermore, Tec kinase inhibition reduces osteoclastic bone resorption in models of osteoporosis and inflammation-induced bone destruction. Thus, this study reveals the importance of the osteoclastogenic signaling complex composed of tyrosine kinases, which may provide the molecular basis for a new therapeutic strategy.
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Affiliation(s)
- Masahiro Shinohara
- Department of Cell Signaling, Graduate School, Tohoku University, Seiryo-machi 4-1, Aoba-ku, Sendai, Miyagi 980-8575, Japan
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47
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Weber M, Treanor B, Depoil D, Shinohara H, Harwood NE, Hikida M, Kurosaki T, Batista FD. Phospholipase C-gamma2 and Vav cooperate within signaling microclusters to propagate B cell spreading in response to membrane-bound antigen. ACTA ACUST UNITED AC 2008; 205:853-68. [PMID: 18362175 PMCID: PMC2292224 DOI: 10.1084/jem.20072619] [Citation(s) in RCA: 143] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
B cell receptor (BCR) recognition of membrane-bound antigen initiates a spreading and contraction response, the extent of which is controlled through the formation of signaling-active BCR-antigen microclusters and ultimately affects the outcome of B cell activation. We followed a genetic approach to define the molecular requirements of BCR-induced spreading and microcluster formation. We identify a key role for phospholipase C-γ2 (PLCγ2), Vav, B cell linker, and Bruton's tyrosine kinase in the formation of highly coordinated “microsignalosomes,” the efficient assembly of which is absolutely dependent on Lyn and Syk. Using total internal reflection fluorescence microscopy, we examine at high resolution the recruitment of PLCγ2 and Vav to microsignalosomes, establishing a novel synergistic relationship between the two. Thus, we demonstrate the importance of cooperation between components of the microsignalosome in the amplification of signaling and propagation of B cell spreading, which is critical for appropriate B cell activation.
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Affiliation(s)
- Michele Weber
- Lymphocyte Interaction Laboratory, London Research Institute, Cancer Research UK, London WC2A 3PX, England, UK
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48
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Conformational plasticity and navigation of signaling proteins in antigen-activated B lymphocytes. Adv Immunol 2008; 97:251-81. [PMID: 18501772 DOI: 10.1016/s0065-2776(08)00005-9] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Over the past two decades our view of the B cell antigen receptor (BCR) has fundamentally changed. Being initially regarded as a mute antibody orphan of the B cell surface, the BCR turned out to be a complex multimolecular machine monitoring almost all stages of B cell development, selection, and activation through a plethora of ubiquitously and cell-type-specific effector proteins. A comprehensive understanding of the many BCR signaling facets is still out but a few common biochemical principles outlined in this review operate at the level of receptor activation and orchestrate specific wiring of intracellular transducer cascades. First, initiation and processing of antigen-induced signal transduction relies on transient conformational changes in the signaling proteins to trigger their physical interaction with downstream elements. Second, this dynamic assembly of signalosomes occurs at distinct subcellular locations, most prominently the plasma membrane, which requires dynamic relocalization of one or more of the engaged molecules. For both, precise complex formation and efficient subcellular targeting, B cell signaling components are equipped with a variety of protein interaction domains. Here we provide an overview on how these simple rules are applied by a limited number of transmembrane and cytosolic proteins to convert BCR ligation into Ca(2+) mobilization and Ras activation in an adjustable manner.
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49
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Martin DA, Lu L, Cascalho M, Wu GE. Maintenance of Surrogate Light Chain Expression Induces Developmental Delay in Early B Cell Compartment. THE JOURNAL OF IMMUNOLOGY 2007; 179:4996-5005. [PMID: 17911584 DOI: 10.4049/jimmunol.179.8.4996] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
The production of a mature B cell requires passage through a number of developmental checkpoints. The pre-BCR plays a critical role in passage through the pro-B cell/pre-B cell checkpoint, and thus plays a central role in regulating the differentiation of a B cell. Due to the significance of this receptor, it is imperative that pre-BCR expression and function are precisely regulated. In this study, we have investigated a system in which the regulation of the pre-BCR is altered. We have found that continued expression of components of the pre-BCR (lambda5) resulted in a delay in the kinetics of B cell maturation. Pro-B cells from normal mouse bone marrow retrovirally infected with lambda5 exhibited a delay in differentiation. As compared with wild-type cells at the same time point, there is a reduction in the presence of cell surface markers that indicate developmental progression, and there is a 6- to 16-fold decrease in the production of Ig-positive cells in B cell maturation assays. The capacity to alter B cell progression by modifying and extending pre-BCR expression argues that the receptor and its associated signals play a unique role in directing developmental outcomes.
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Affiliation(s)
- Denise A Martin
- Department of Kinesiology and Health Science, York University, Toronto, Ontario, Canada
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50
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Scharenberg AM, Humphries LA, Rawlings DJ. Calcium signalling and cell-fate choice in B cells. Nat Rev Immunol 2007; 7:778-89. [PMID: 17853903 PMCID: PMC2743935 DOI: 10.1038/nri2172] [Citation(s) in RCA: 159] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Alterations in the cytosolic concentration of calcium ions (Ca2+) transmit information that is crucial for the development and function of B cells. Cytosolic Ca2+ concentration is determined by a balance of active transport and gradient-driven Ca2+ fluxes, both of which are subject to the influence of multiple receptors and environmental sensing pathways. Recent advances in genomics have allowed for the compilation of an increasingly comprehensive list of Ca2+ transporters and channels expressed by B cells. The increasing understanding of the function and regulation of these proteins has begun to shift the frontier of Ca2+ physiology in B cells from molecular analysis to determining how diverse inputs to cytosolic Ca2+ concentration are integrated in specific immunological contexts.
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Affiliation(s)
- Andrew M. Scharenberg
- Departments of Pediatrics and Immunology, University of Washington School of Medicine and, Children's Hospital and Regional Medical Center, Suite 300, 307 Westlake Ave, Seattle, WA 98109, USA
| | - Lisa A. Humphries
- Departments of Pediatrics and Immunology, University of Washington School of Medicine and, Children's Hospital and Regional Medical Center, Suite 300, 307 Westlake Ave, Seattle, WA 98109, USA
| | - David J. Rawlings
- Departments of Pediatrics and Immunology, University of Washington School of Medicine and, Children's Hospital and Regional Medical Center, Suite 300, 307 Westlake Ave, Seattle, WA 98109, USA
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