1
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Lin DYW, Kueffer LE, Juneja P, Wales TE, Engen JR, Andreotti AH. Conformational heterogeneity of the BTK PHTH domain drives multiple regulatory states. eLife 2024; 12:RP89489. [PMID: 38189455 PMCID: PMC10945472 DOI: 10.7554/elife.89489] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2024] Open
Abstract
Full-length Bruton's tyrosine kinase (BTK) has been refractory to structural analysis. The nearest full-length structure of BTK to date consists of the autoinhibited SH3-SH2-kinase core. Precisely how the BTK N-terminal domains (the Pleckstrin homology/Tec homology [PHTH] domain and proline-rich regions [PRR] contain linker) contribute to BTK regulation remains unclear. We have produced crystals of full-length BTK for the first time but despite efforts to stabilize the autoinhibited state, the diffraction data still reveal only the SH3-SH2-kinase core with no electron density visible for the PHTH-PRR segment. Cryo-electron microscopy (cryoEM) data of full-length BTK, on the other hand, provide the first view of the PHTH domain within full-length BTK. CryoEM reconstructions support conformational heterogeneity in the PHTH-PRR region wherein the globular PHTH domain adopts a range of states arrayed around the autoinhibited SH3-SH2-kinase core. On the way to activation, disassembly of the SH3-SH2-kinase core opens a new autoinhibitory site on the kinase domain for PHTH domain binding that is ultimately released upon interaction of PHTH with phosphatidylinositol (3,4,5)-trisphosphate. Membrane-induced dimerization activates BTK and we present here a crystal structure of an activation loop swapped BTK kinase domain dimer that likely represents the conformational state leading to trans-autophosphorylation. Together, these data provide the first structural elucidation of full-length BTK and allow a deeper understanding of allosteric control over the BTK kinase domain during distinct stages of activation.
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Affiliation(s)
- David Yin-wei Lin
- Roy J. Carver Department of Biochemistry, Biophysics and Molecular Biology, Iowa State UniversityAmesUnited States
| | - Lauren E Kueffer
- Roy J. Carver Department of Biochemistry, Biophysics and Molecular Biology, Iowa State UniversityAmesUnited States
| | - Puneet Juneja
- Cryo-EM Facility, Office of Biotechnology, Iowa State UniversityAmesUnited States
| | - Thomas E Wales
- Department of Chemistry and Chemical Biology, Northeastern UniversityBostonUnited States
| | - John R Engen
- Department of Chemistry and Chemical Biology, Northeastern UniversityBostonUnited States
| | - Amy H Andreotti
- Roy J. Carver Department of Biochemistry, Biophysics and Molecular Biology, Iowa State UniversityAmesUnited States
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2
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Li W, Sano R, Apatira M, DeAnda F, Gururaja T, Yang M, Lundgaard G, Pan C, Liu J, Zhai Y, Yoon WH, Wang L, Tse C, Souers AJ, Lee CH. Bruton's Tyrosine Kinase Inhibitors with Distinct Binding Modes Reveal Differential Functional Impact on B-Cell Receptor Signaling. Mol Cancer Ther 2024; 23:35-46. [PMID: 37735104 PMCID: PMC10762339 DOI: 10.1158/1535-7163.mct-22-0642] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2022] [Revised: 04/17/2023] [Accepted: 09/14/2023] [Indexed: 09/23/2023]
Abstract
Small molecule inhibitors of Bruton's tyrosine kinase (BTK) have been approved for the treatment of multiple B-cell malignancies and are being evaluated for autoimmune and inflammatory diseases. Various BTK inhibitors (BTKi) have distinct potencies, selectivity profiles, and binding modes within the ATP-binding site. On the basis of the latter feature, BTKis can be classified into those that occupy the back-pocket, H3 pocket, and the hinge region only. Hypothesizing that differing binding modes may have differential impact on the B-cell receptor (BCR) signaling pathway, we evaluated the activities of multiple BTKis in B-cell lymphoma models in vitro and in vivo. We demonstrated that, although all three types of BTKis potently inhibited BTK-Y223 autophosphorylation and phospholipase C gamma 2 (PLCγ2)-Y1217 transphosphorylation, hinge-only binders were defective in inhibiting BTK-mediated calcium mobilization upon BCR activation. In addition, PLCγ2 activation was effectively blocked by back-pocket and H3 pocket binders but not by hinge-only binders. Further investigation using TMD8 cells deficient in Rac family small GTPase 2 (RAC2) revealed that RAC2 functioned as a bypass mechanism, allowing for residual BCR signaling and PLCγ2 activation when BTK kinase activity was fully inhibited by the hinge-only binders. These data reveal a kinase activity-independent function of BTK, involving RAC2 in transducing BCR signaling events, and provide mechanistic rationale for the selection of clinical candidates for B-cell lymphoma indications.
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Affiliation(s)
- Wei Li
- Oncology Discovery, AbbVie Inc., South San Francisco, California
| | - Renata Sano
- Oncology Discovery, AbbVie Inc., South San Francisco, California
| | - Mutiah Apatira
- Oncology Discovery, AbbVie Inc., South San Francisco, California
| | - Felix DeAnda
- Oncology Discovery, AbbVie Inc., South San Francisco, California
| | | | - Muhua Yang
- Oncology Discovery, AbbVie Inc., South San Francisco, California
| | - Greta Lundgaard
- Drug Discovery Science and Technology, AbbVie Inc., Lake County, Illinois
| | - Chin Pan
- Oncology Discovery, AbbVie Inc., South San Francisco, California
| | - Jing Liu
- Oncology Discovery, AbbVie Inc., South San Francisco, California
| | - Yongjiao Zhai
- Oncology Discovery, AbbVie Inc., South San Francisco, California
| | - Woo Hyun Yoon
- Oncology Discovery, AbbVie Inc., South San Francisco, California
| | - Longcheng Wang
- Oncology Discovery, AbbVie Inc., South San Francisco, California
| | - Chris Tse
- Oncology Discovery, AbbVie Inc., Lake County, Illinois
| | | | - Chih-Hung Lee
- Oncology Discovery, AbbVie Inc., South San Francisco, California
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3
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Kueffer LE, Lin DYW, Amatya N, Serrenho J, Joseph RE, Courtney AH, Andreotti AH. Screening and Characterization of Allosteric Small Molecules Targeting Bruton's Tyrosine Kinase. Biochemistry 2024; 63:94-106. [PMID: 38091504 DOI: 10.1021/acs.biochem.3c00362] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2024]
Abstract
Bruton's Tyrosine Kinase (BTK) is a nonreceptor tyrosine kinase that belongs to the TEC family. Mutations in the BTK gene cause X-linked agammaglobulinemia (XLA) leading to an arrest in B-cell development. BTK is also a drug target for B-cell lymphomas that rely on an intact B-cell receptor signaling cascade for survival. All FDA approved drugs for BTK target the ATP binding site of the catalytic kinase domain, leading to potential adverse events due to off-target inhibition. In addition, acquired resistance mutations occur in a subset of patients, rendering available BTK inhibitors ineffective. Therefore, allosteric sites on BTK should be explored for drug development to target BTK more specifically and in combination with active site inhibitors. Virtual screening against nonactive site pockets and in vitro experiments resulted in a series of small molecules that bind to BTK outside of the active site. We characterized these compounds using biochemical and biophysical techniques and narrowed our focus to compound "C2". C2 activates full-length BTK and smaller multidomain BTK fragments but not the isolated kinase domain, consistent with an allosteric mode of action. Kinetic experiments reveal a C2-mediated decrease in Km and an increase in kcat leading to an overall increase in the catalytic efficiency of BTK. C2 is also capable of activating the BTK XLA mutants. These proof-of-principle data reveal that BTK can be targeted allosterically with small molecules, providing an alternative to active site BTK inhibitors.
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Affiliation(s)
- Lauren E Kueffer
- Roy J. Carver Department of Biochemistry, Biophysics, and Molecular Biology, Iowa State University, Ames, Iowa 50011, United States
| | - David Yin-Wei Lin
- Roy J. Carver Department of Biochemistry, Biophysics, and Molecular Biology, Iowa State University, Ames, Iowa 50011, United States
| | - Neha Amatya
- Roy J. Carver Department of Biochemistry, Biophysics, and Molecular Biology, Iowa State University, Ames, Iowa 50011, United States
| | - Joseph Serrenho
- Department of Pharmacology, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Raji E Joseph
- Roy J. Carver Department of Biochemistry, Biophysics, and Molecular Biology, Iowa State University, Ames, Iowa 50011, United States
| | - Adam H Courtney
- Department of Pharmacology, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Amy H Andreotti
- Roy J. Carver Department of Biochemistry, Biophysics, and Molecular Biology, Iowa State University, Ames, Iowa 50011, United States
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4
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Joseph RE, Wales TE, Jayne S, Britton RG, Fulton DB, Engen JR, Dyer MJS, Andreotti AH. Impact of the clinically approved BTK inhibitors on the conformation of full-length BTK and analysis of the development of BTK resistance mutations in chronic lymphocytic leukemia. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.12.18.572223. [PMID: 38187560 PMCID: PMC10769265 DOI: 10.1101/2023.12.18.572223] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2024]
Abstract
Inhibition of Bruton's tyrosine kinase (BTK) has proven to be highly effective in the treatment of B-cell malignancies such as chronic lymphocytic leukemia (CLL), autoimmune disorders and multiple sclerosis. Since the approval of the first BTK inhibitor (BTKi), Ibrutinib, several other inhibitors including Acalabrutinib, Zanubrutinib, Tirabrutinib and Pirtobrutinib have been clinically approved. All are covalent active site inhibitors, with the exception of the reversible active site inhibitor Pirtobrutinib. The large number of available inhibitors for the BTK target creates challenges in choosing the most appropriate BTKi for treatment. Side-by-side comparisons in CLL have shown that different inhibitors may differ in their treatment efficacy. Moreover, the nature of the resistance mutations that arise in patients appears to depend on the specific BTKi administered. We have previously shown that Ibrutinib binding to the kinase active site causes unanticipated long-range effects on the global conformation of BTK (Joseph, R.E., et al., 2020, https://doi.org/10.7554/eLife.60470 ). Here we show that binding of each of the five approved BTKi to the kinase active site brings about distinct allosteric changes that alter the conformational equilibrium of full-length BTK. Additionally, we provide an explanation for the resistance mutation bias observed in CLL patients treated with different BTKi and characterize the mechanism of action of two common resistance mutations: BTK T474I and L528W.
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5
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Lin DYW, Kueffer LE, Juneja P, Wales TE, Engen JR, Andreotti AH. Conformational heterogeneity of the BTK PHTH domain drives multiple regulatory states. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.06.02.543453. [PMID: 37786675 PMCID: PMC10541622 DOI: 10.1101/2023.06.02.543453] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/04/2023]
Abstract
Full-length BTK has been refractory to structural analysis. The nearest full-length structure of BTK to date consists of the autoinhibited SH3-SH2-kinase core. Precisely how the BTK N-terminal domains (the Pleckstrin homology/Tec homology (PHTH) domain and proline-rich regions (PRR) contain linker) contribute to BTK regulation remains unclear. We have produced crystals of full-length BTK for the first time but despite efforts to stabilize the autoinhibited state, the diffraction data still reveals only the SH3-SH2-kinase core with no electron density visible for the PHTH-PRR segment. CryoEM data of full-length BTK, on the other hand, provide the first view of the PHTH domain within full-length BTK. CryoEM reconstructions support conformational heterogeneity in the PHTH-PRR region wherein the globular PHTH domain adopts a range of states arrayed around the autoinhibited SH3-SH2-kinase core. On the way to activation, disassembly of the SH3-SH2-kinase core opens a new autoinhibitory site on the kinase domain for PHTH domain binding that is ultimately released upon interaction of PHTH with PIP3. Membrane-induced dimerizationactivates BTK and we present here a crystal structure of an activation loop swapped BTK kinase domain dimer that likely represents the conformational state leading to transautophosphorylation. Together, these data provide the first structural elucidation of full-length BTK and allow a deeper understanding of allosteric control over the BTK kinase domain during distinct stages of activation.
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6
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Yu J, Boehr DD. Regulatory mechanisms triggered by enzyme interactions with lipid membrane surfaces. Front Mol Biosci 2023; 10:1306483. [PMID: 38099197 PMCID: PMC10720463 DOI: 10.3389/fmolb.2023.1306483] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2023] [Accepted: 11/17/2023] [Indexed: 12/17/2023] Open
Abstract
Recruitment of enzymes to intracellular membranes often modulates their catalytic activity, which can be important in cell signaling and membrane trafficking. Thus, re-localization is not only important for these enzymes to gain access to their substrates, but membrane interactions often allosterically regulate enzyme function by inducing conformational changes across different time and amplitude scales. Recent structural, biophysical and computational studies have revealed how key enzymes interact with lipid membrane surfaces, and how this membrane binding regulates protein structure and function. This review summarizes the recent progress in understanding regulatory mechanisms involved in enzyme-membrane interactions.
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Affiliation(s)
| | - David D. Boehr
- Department of Chemistry, The Pennsylvania State University, University Park, PA, United States
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7
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Yang Y, Chong Z, Vihinen M. PON-Fold: Prediction of Substitutions Affecting Protein Folding Rate. Int J Mol Sci 2023; 24:13023. [PMID: 37629203 PMCID: PMC10455311 DOI: 10.3390/ijms241613023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2023] [Revised: 08/08/2023] [Accepted: 08/09/2023] [Indexed: 08/27/2023] Open
Abstract
Most proteins fold into characteristic three-dimensional structures. The rate of folding and unfolding varies widely and can be affected by variations in proteins. We developed a novel machine-learning-based method for the prediction of the folding rate effects of amino acid substitutions in two-state folding proteins. We collected a data set of experimentally defined folding rates for variants and used them to train a gradient boosting algorithm starting with 1161 features. Two predictors were designed. The three-class classifier had, in blind tests, specificity and sensitivity ranging from 0.324 to 0.419 and from 0.256 to 0.451, respectively. The other tool was a regression predictor that showed a Pearson correlation coefficient of 0.525. The error measures, mean absolute error and mean squared error, were 0.581 and 0.603, respectively. One of the previously presented tools could be used for comparison with the blind test data set, our method called PON-Fold showed superior performance on all used measures. The applicability of the tool was tested by predicting all possible substitutions in a protein domain. Predictions for different conformations of proteins, open and closed forms of a protein kinase, and apo and holo forms of an enzyme indicated that the choice of the structure had a large impact on the outcome. PON-Fold is freely available.
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Affiliation(s)
- Yang Yang
- School of Computer Science and Technology, Soochow University, Suzhou 215006, China; (Y.Y.); (Z.C.)
- Collaborative Innovation Center of Novel Software Technology and Industrialization, Nanjing 210000, China
| | - Zhang Chong
- School of Computer Science and Technology, Soochow University, Suzhou 215006, China; (Y.Y.); (Z.C.)
| | - Mauno Vihinen
- Department of Experimental Medical Science, Lund University, BMC B13, SE-221 84 Lund, Sweden
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8
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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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9
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Betzler AC, Strobel H, Abou Kors T, Ezić J, Lesakova K, Pscheid R, Azoitei N, Sporleder J, Staufenberg AR, Drees R, Weissinger SE, Greve J, Doescher J, Theodoraki MN, Schuler PJ, Laban S, Kibe T, Kishida M, Kishida S, Idel C, Hoffmann TK, Lavitrano M, Grassilli E, Brunner C. BTK Isoforms p80 and p65 Are Expressed in Head and Neck Squamous Cell Carcinoma (HNSCC) and Involved in Tumor Progression. Cancers (Basel) 2023; 15:cancers15010310. [PMID: 36612306 PMCID: PMC9818583 DOI: 10.3390/cancers15010310] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2022] [Revised: 12/14/2022] [Accepted: 12/27/2022] [Indexed: 01/04/2023] Open
Abstract
Here, we describe the expression of Bruton's Tyrosine Kinase (BTK) in head and neck squamous cell carcinoma (HNSCC) cell lines as well as in primary HNSCC samples. BTK is a kinase initially thought to be expressed exclusively in cells of hematopoietic origin. Apart from the 77 kDa BTK isoform expressed in immune cells, particularly in B cells, we identified the 80 kDa and 65 kDa BTK isoforms in HNSCC, recently described as oncogenic. Importantly, we revealed that both isoforms are products of the same mRNA. By investigating the mechanism regulating oncogenic BTK-p80/p65 expression in HNSSC versus healthy or benign tissues, our data suggests that the epigenetic process of methylation might be responsible for the initiation of BTK-p80/p65 expression in HNSCC. Our findings demonstrate that chemical or genetic abrogation of BTK activity leads to inhibition of tumor progression in terms of proliferation and vascularization in vitro and in vivo. These observations were associated with cell cycle arrest and increased apoptosis and autophagy. Together, these data indicate BTK-p80 and BTK-p65 as novel HNSCC-associated oncogenes. Owing to the fact that abundant BTK expression is a characteristic feature of primary and metastatic HNSCC, targeting BTK activity appears as a promising therapeutic option for HNSCC patients.
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Affiliation(s)
- Annika C. Betzler
- Department of Oto-Rhino-Laryngology, Ulm University Medical Center, 89075 Ulm, Germany
| | - Hannah Strobel
- Department of Oto-Rhino-Laryngology, Ulm University Medical Center, 89075 Ulm, Germany
| | - Tsima Abou Kors
- Department of Oto-Rhino-Laryngology, Ulm University Medical Center, 89075 Ulm, Germany
| | - Jasmin Ezić
- Department of Oto-Rhino-Laryngology, Ulm University Medical Center, 89075 Ulm, Germany
| | - Kristina Lesakova
- Department of Oto-Rhino-Laryngology, Ulm University Medical Center, 89075 Ulm, Germany
| | - Ronja Pscheid
- Department of Oto-Rhino-Laryngology, Ulm University Medical Center, 89075 Ulm, Germany
| | - Ninel Azoitei
- Department of Internal Medicine I, Ulm University Medical Center, 89081 Ulm, Germany
| | - Johanna Sporleder
- Department of Oto-Rhino-Laryngology, Ulm University Medical Center, 89075 Ulm, Germany
| | | | - Robert Drees
- Department of Oto-Rhino-Laryngology, Ulm University Medical Center, 89075 Ulm, Germany
| | | | - Jens Greve
- Department of Oto-Rhino-Laryngology, Ulm University Medical Center, 89075 Ulm, Germany
| | - Johannes Doescher
- Department of Oto-Rhino-Laryngology, Ulm University Medical Center, 89075 Ulm, Germany
| | | | - Patrick J. Schuler
- Department of Oto-Rhino-Laryngology, Ulm University Medical Center, 89075 Ulm, Germany
| | - Simon Laban
- Department of Oto-Rhino-Laryngology, Ulm University Medical Center, 89075 Ulm, Germany
| | - Toshiro Kibe
- Department of Biochemistry and Genetics, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima 890-8580, Japan
| | - Michiko Kishida
- Department of Biochemistry and Genetics, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima 890-8580, Japan
| | - Shosei Kishida
- Department of Biochemistry and Genetics, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima 890-8580, Japan
| | - Christian Idel
- Department of Otorhinolaryngology, University Hospital Schleswig-Holstein, University of Luebeck, Campus Luebeck, 23538 Luebeck, Germany
| | - Thomas K. Hoffmann
- Department of Oto-Rhino-Laryngology, Ulm University Medical Center, 89075 Ulm, Germany
| | - Marialuisa Lavitrano
- School of Medicine and Surgery, University of Milano-Bicocca, 20900 Monza, Italy
| | - Emanuela Grassilli
- School of Medicine and Surgery, University of Milano-Bicocca, 20900 Monza, Italy
| | - Cornelia Brunner
- Department of Oto-Rhino-Laryngology, Ulm University Medical Center, 89075 Ulm, Germany
- Correspondence: ; Tel.: +49-731-500-59714; Fax: +49-731-500-59565
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10
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Du S, Alvarado JJ, Wales TE, Moroco JA, Engen JR, Smithgall TE. ATP-site inhibitors induce unique conformations of the acute myeloid leukemia-associated Src-family kinase, Fgr. Structure 2022; 30:1508-1517.e3. [PMID: 36115344 PMCID: PMC9637690 DOI: 10.1016/j.str.2022.08.008] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2022] [Revised: 07/28/2022] [Accepted: 08/23/2022] [Indexed: 11/26/2022]
Abstract
The Src-family kinase Fgr is expressed primarily in myeloid hematopoietic cells and contributes to myeloid leukemia. Here, we present X-ray crystal structures of Fgr bound to the ATP-site inhibitors A-419259 and TL02-59, which show promise as anti-leukemic agents. A-419259 induces a closed Fgr conformation, with the SH3 and SH2 domains engaging the SH2-kinase linker and C-terminal tail, respectively. In the Fgr:A-419259 complex, the activation loop of one monomer inserts into the active site of the other, providing a snapshot of trans-autophosphorylation. By contrast, TL02-59 binding induced SH2 domain displacement from the C-terminal tail and SH3 domain release from the linker. Solution studies using HDX MS were consistent with the crystal structures, with A-419259 reducing and TL02-59 enhancing solvent exposure of the SH3 domain. These structures demonstrate that allosteric connections between the kinase and regulatory domains of Src-family kinases are regulated by the ligand bound to the active site.
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Affiliation(s)
- Shoucheng Du
- Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Bridgeside Point II, Suite 523, 450 Technology Drive, Pittsburgh, PA 15219, USA
| | - John J Alvarado
- Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Bridgeside Point II, Suite 523, 450 Technology Drive, Pittsburgh, PA 15219, USA
| | - Thomas E Wales
- Department of Chemistry and Chemical Biology, Northeastern University, Boston, MA 02115, USA
| | - Jamie A Moroco
- Department of Chemistry and Chemical Biology, Northeastern University, Boston, MA 02115, USA
| | - John R Engen
- Department of Chemistry and Chemical Biology, Northeastern University, Boston, MA 02115, USA
| | - Thomas E Smithgall
- Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Bridgeside Point II, Suite 523, 450 Technology Drive, Pittsburgh, PA 15219, USA.
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11
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Comparison of Intermolecular Interactions of Irreversible and Reversible Inhibitors with Bruton’s Tyrosine Kinase via Molecular Dynamics Simulations. Molecules 2022; 27:molecules27217451. [DOI: 10.3390/molecules27217451] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2022] [Revised: 10/26/2022] [Accepted: 10/28/2022] [Indexed: 11/06/2022] Open
Abstract
Bruton’s tyrosine kinase (BTK) is a key protein from the TEC family and is involved in B-cell lymphoma occurrence and development. Targeting BTK is therefore an effective strategy for B-cell lymphoma treatment. Since previous studies on BTK have been limited to structure-function analyses of static protein structures, the dynamics of conformational change of BTK upon inhibitor binding remain unclear. Here, molecular dynamics simulations were conducted to investigate the molecular mechanisms of association and dissociation of a reversible (ARQ531) and irreversible (ibrutinib) small-molecule inhibitor to/from BTK. The results indicated that the BTK kinase domain was found to be locked in an inactive state through local conformational changes in the DFG motif, and P-, A-, and gatekeeper loops. The binding of the inhibitors drove the outward rotation of the C-helix, resulting in the upfolded state of Trp395 and the formation of the salt bridge of Glu445-Arg544, which maintained the inactive conformation state. Met477 and Glu475 in the hinge region were found to be the key residues for inhibitor binding. These findings can be used to evaluate the inhibitory activity of the pharmacophore and applied to the design of effective BTK inhibitors. In addition, the drug resistance to the irreversible inhibitor Ibrutinib was mainly from the strong interaction of Cys481, which was evidenced by the mutational experiment, and further confirmed by the measurement of rupture force and rupture times from steered molecular dynamics simulation. Our results provide mechanistic insights into resistance against BTK-targeting drugs and the key interaction sites for the development of high-quality BTK inhibitors. The steered dynamics simulation also offers a means to rapidly assess the binding capacity of newly designed inhibitors.
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12
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Aryal M, Lin D, Regan K, Du S, Shi H, Alvarado JJ, Ilina TV, Andreotti AH, Smithgall TE. The HIV-1 protein Nef activates the Tec family kinase Btk by stabilizing an intermolecular SH3-SH2 domain interaction. Sci Signal 2022; 15:eabn8359. [PMID: 36126115 PMCID: PMC9830684 DOI: 10.1126/scisignal.abn8359] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
The Nef protein produced by the viruses HIV-1 and SIV drives efficient viral replication partially by inducing constitutive activation of host cell tyrosine kinases, including members of the Src and Tec families. Here, we uncovered the mechanism by which both HIV-1 and SIV Nef enhanced the activity of the Tec family kinase Btk in vitro and in cells. A Nef mutant that could not bind to the SH3 domain of Src family kinases activated Btk to the same extent as did wild-type Nef, demonstrating that Nef activated Src and Tec family kinases by distinct mechanisms. The Btk SH3-SH2 region formed a homodimer requiring the CD loop in the SH2 domain, which was stabilized by the binding of Nef homodimers. Alanine substitution of Pro327 in the CD loop of the Btk SH2 domain destabilized SH3-SH2 dimers, abolished the interaction with Nef, and prevented activation by Nef in vitro. In cells, Nef stabilized and activated wild-type but not P327A Btk homodimers at the plasma membrane. These data reveal that the interaction with Nef stabilizes Btk dimers through the SH3-SH2 interface to promote kinase activity and show that the HIV-1 Nef protein evolved distinct mechanisms to activate Src and Tec family tyrosine kinases to enhance viral replication.
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Affiliation(s)
- Manish Aryal
- Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh PA, 15219 USA
| | - David Lin
- Roy J. Carver Department of Biochemistry, Biophysics and Molecular Biology, Iowa State University, Ames, IA, 50011 USA
| | - Kiera Regan
- Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh PA, 15219 USA
| | - Shoucheng Du
- Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh PA, 15219 USA
| | - Haibin Shi
- Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh PA, 15219 USA
| | - John J. Alvarado
- Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh PA, 15219 USA
| | - Tatiana V. Ilina
- Department of Structural Biology, University of Pittsburgh School of Medicine, Pittsburgh PA, 15260 USA
| | - Amy H. Andreotti
- Roy J. Carver Department of Biochemistry, Biophysics and Molecular Biology, Iowa State University, Ames, IA, 50011 USA
| | - Thomas E. Smithgall
- Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh PA, 15219 USA,To whom correspondence should be addressed: Thomas E. Smithgall, Ph.D., Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Bridgeside Point II, Suite 523, 450 Technology Drive, Pittsburgh, PA 15219, Tel. 412-648-8106, Fax 412-624-8997,
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13
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Grassilli E, Cerrito MG, Lavitrano M. BTK, the new kid on the (oncology) block? Front Oncol 2022; 12:944538. [PMID: 35992808 PMCID: PMC9386470 DOI: 10.3389/fonc.2022.944538] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2022] [Accepted: 07/14/2022] [Indexed: 01/17/2023] Open
Abstract
In the last decade data piled up indicating that BTK – for twenty years considered as a “private matter” of bone marrow-derived cells – it is expressed and plays important and different roles also outside of the hematopoietic compartment and, most notably, in tumor cells. Initial evidence that BTK plays a critical role in B cell-derived malignancies prompted the chase for specific inhibitors, the forefather of which entered the clinic in a record time and paved the way for an ever increasing number of new molecules to be trialed. The growing interests in BTK also led to the discovery that, in solid tumors, two novel isoforms are mainly expressed and actionable liabilities for target therapy. Remarkably, the different isoforms appear to be involved in different signaling pathways which will have to be attentively specified in order to define the area of therapeutic intervention. In this perspective we briefly summarize the progress made in the last decade in studying BTK and its isoforms in cancer cells and define the open questions to be addressed in order to get the most benefits from its targeting for therapeutic purposes.
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14
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Joseph RE, Lowe J, Fulton DB, Engen JR, Wales TE, Andreotti AH. The Conformational State of the BTK Substrate PLCγ Contributes to Ibrutinib Resistance. J Mol Biol 2022; 434:167422. [PMID: 34954235 PMCID: PMC8924901 DOI: 10.1016/j.jmb.2021.167422] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2021] [Revised: 12/06/2021] [Accepted: 12/16/2021] [Indexed: 12/17/2022]
Abstract
Mutations in PLCγ, a substrate of the tyrosine kinase BTK, are often found in patients who develop resistance to the BTK inhibitor Ibrutinib. However, the mechanisms by which these PLCγ mutations cause Ibrutinib resistance are unclear. Under normal signaling conditions, BTK mediated phosphorylation of Y783 within the PLCγ cSH2-linker promotes the intramolecular association of this site with the adjacent cSH2 domain resulting in active PLCγ. Thus, the cSH2-linker region in the center of the regulatory gamma specific array (γSA) of PLCγ is a key feature controlling PLCγ activity. Even in the unphosphorylated state this linker exists in a conformational equilibrium between free and bound to the cSH2 domain. The position of this equilibrium is optimized within the properly regulated PLCγ enzyme but may be altered in the context of mutations. We therefore assessed the conformational status of four resistance associated mutations within the PLCγ γSA and find that they each alter the conformational equilibrium of the γSA leading to a shift toward active PLCγ. Interestingly, two distinct modes of mutation induced activation are revealed by this panel of Ibrutinib resistance mutations. These findings, along with the recently determined structure of fully autoinhibited PLCγ, provide new insight into the nature of the conformational change that occurs within the γSA regulatory region to affect PLCγ activation. Improving our mechanistic understanding of how B cell signaling escapes Ibrutinib treatment via mutations in PLCγ will aid in the development of strategies to counter drug resistance.
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Affiliation(s)
- Raji E Joseph
- Roy J. Carver Department of Biochemistry, Biophysics and Molecular Biology, Iowa State University, Ames, IA 50011, USA
| | - Jacques Lowe
- Roy J. Carver Department of Biochemistry, Biophysics and Molecular Biology, Iowa State University, Ames, IA 50011, USA
| | - D Bruce Fulton
- Roy J. Carver Department of Biochemistry, Biophysics and Molecular Biology, Iowa State University, Ames, IA 50011, USA. https://twitter.com/dbfulton
| | - John R Engen
- Department of Chemistry and Chemical Biology, Northeastern University, Boston, MA 02115, USA. https://twitter.com/jrengen
| | - Thomas E Wales
- Department of Chemistry and Chemical Biology, Northeastern University, Boston, MA 02115, USA.
| | - Amy H Andreotti
- Roy J. Carver Department of Biochemistry, Biophysics and Molecular Biology, Iowa State University, Ames, IA 50011, USA.
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15
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Lowe J, Joseph RE, Andreotti AH. Conformational switches that control the TEC kinase – PLCγ signaling axis. J Struct Biol X 2022; 6:100061. [PMID: 35128378 PMCID: PMC8803661 DOI: 10.1016/j.yjsbx.2022.100061] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2021] [Revised: 01/15/2022] [Accepted: 01/18/2022] [Indexed: 11/27/2022] Open
Abstract
TEC kinases and PLCγ transition between autoinhibited state and active conformation. PLCγ structures reveal both autoinhibited form and active form of gamma specific array (γSA); the four regulatory domains unique to the PLCγ isozymes. Domain dynamics likely control activation mechanism. PLCγ phosphorylation triggers conformational switch.
Cell surface receptors such as the T-cell receptor (TCR) and B-cell receptor (BCR) engage with external stimuli to transmit information into the cell and initiate a cascade of signaling events that lead to gene expression that drives the immune response. At the heart of controlling T- and B-cell cell signaling, phospholipase Cγ hydrolyzes membrane associated PIP2, leading to generation of the second messengers IP3 and DAG. These small molecules trigger mobilization of intracellular Ca2+ and promote transcription factor transport into the nucleus launching the adaptive immune response. The TEC family kinases are responsible for phosphorylating and activating PLCγ, and our group aims to understand mechanisms that regulate immune cell signal transduction by focusing on this kinase/phospholipase axis in T-cells and B-cells. Here, we review the current molecular level understanding of how the TEC kinases (ITK and BTK) and PLCγ1/2 are autoinhibited prior to activation of cell surface receptors, how TEC kinases are activated to specifically recognize the PLCγ substrate, and how conformational changes induced by phosphorylation trigger PLCγ activation.
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16
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Linley AJ, Karydis LI, Mondru AK, D'Avola A, Al Shmrany H, Cicconi S, Griffin R, Forconi F, Pettitt AR, Kalakonda N, Rawstron AC, Hillmen P, Steele AJ, MacEwan DJ, Packham G, Prior IA, Slupsky JR. Kinobead Profiling Reveals Reprogramming of BCR Signaling in Response to Therapy within Primary CLL Cells. Clin Cancer Res 2021; 27:5647-5659. [PMID: 34380642 PMCID: PMC9662893 DOI: 10.1158/1078-0432.ccr-21-0161] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2021] [Revised: 04/15/2021] [Accepted: 07/30/2021] [Indexed: 01/07/2023]
Abstract
PURPOSE B-cell receptor (BCR) signaling is critical for the pathogenesis of chronic lymphocytic leukemia (CLL), promoting both malignant cell survival and disease progression. Although vital, understanding of the wider signaling network associated with malignant BCR stimulation is poor. This is relevant with respect to potential changes in response to therapy, particularly involving kinase inhibitors. In the current study, we describe a novel high-resolution approach to investigate BCR signaling in primary CLL cells and track the influence of therapy on signaling response. EXPERIMENTAL DESIGN A kinobead/mass spectrometry-based protocol was used to study BCR signaling in primary CLL cells. Longitudinal analysis of samples donated by clinical trial patients was used to investigate the impact of chemoimmunotherapy and ibrutinib on signaling following surface IgM engagement. Complementary Nanostring and immunoblotting analysis was used to verify our findings. RESULTS Our protocol isolated a unique, patient-specific signature of over 30 kinases from BCR-stimulated CLL cells. This signature was associated with 13 distinct Kyoto Encyclopedia of Genes and Genomes pathways and showed significant change in cells from treatment-naïve patients compared with those from patients who had previously undergone therapy. This change was validated by longitudinal analysis of clinical trials samples where BCR-induced kinome responses in CLL cells altered between baseline and disease progression in patients failing chemoimmunotherapy and between baseline and treatment in patients taking ibrutinib. CONCLUSIONS These data comprise the first comprehensive proteomic investigation of the BCR signaling response within CLL cells and reveal unique evidence that these cells undergo adaptive reprogramming of this signaling in response to therapy.
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Affiliation(s)
- Adam J Linley
- Department of Molecular Physiology and Cell Signaling, Institute of Systems, Molecular and Integrative Biology, University of Liverpool, Liverpool, United Kingdom.
| | - Laura I Karydis
- School of Cancer Sciences, Cancer Research UK Centre, University of Southampton, Southampton, United Kingdom
| | - Anil K Mondru
- Department of Molecular and Clinical Cancer Medicine, Institute of Systems, Molecular and Integrative Biology, University of Liverpool, Liverpool, United Kingdom
| | - Annalisa D'Avola
- School of Cancer Sciences, Cancer Research UK Centre, University of Southampton, Southampton, United Kingdom
| | - Humood Al Shmrany
- Department of Molecular and Clinical Cancer Medicine, Institute of Systems, Molecular and Integrative Biology, University of Liverpool, Liverpool, United Kingdom
- Department of Medical Laboratory Sciences, College of Applied Medical Sciences, Prince Sattam Bin Abdulaziz University, Al-Kharj, Saudi Arabia
| | - Silvia Cicconi
- Cancer Research Clinical Trials Unit, University of Liverpool, Liverpool, United Kingdom
| | - Rebecca Griffin
- Cancer Research Clinical Trials Unit, University of Liverpool, Liverpool, United Kingdom
| | - Francesco Forconi
- School of Cancer Sciences, Cancer Research UK Centre, University of Southampton, Southampton, United Kingdom
| | - Andrew R Pettitt
- Department of Molecular and Clinical Cancer Medicine, Institute of Systems, Molecular and Integrative Biology, University of Liverpool, Liverpool, United Kingdom
| | - Nagesh Kalakonda
- Department of Molecular and Clinical Cancer Medicine, Institute of Systems, Molecular and Integrative Biology, University of Liverpool, Liverpool, United Kingdom
| | - Andrew C Rawstron
- Department of Haematology, Leeds Teaching Hospitals NHS Trust, Leeds, United Kingdom
| | - Peter Hillmen
- Faculty of Medicine and Health, School of Medicine, University of Leeds, Wellcome Trust Brenner Building, Leeds, United Kingdom
| | - Andrew J Steele
- School of Cancer Sciences, Cancer Research UK Centre, University of Southampton, Southampton, United Kingdom
| | - David J MacEwan
- Department of Pharmacology and Therapeutics, Institute of Systems, Molecular and Integrative Biology, University of Liverpool, Liverpool, United Kingdom
| | - Graham Packham
- School of Cancer Sciences, Cancer Research UK Centre, University of Southampton, Southampton, United Kingdom
| | - Ian A Prior
- Department of Molecular Physiology and Cell Signaling, Institute of Systems, Molecular and Integrative Biology, University of Liverpool, Liverpool, United Kingdom
| | - Joseph R Slupsky
- Department of Molecular and Clinical Cancer Medicine, Institute of Systems, Molecular and Integrative Biology, University of Liverpool, Liverpool, United Kingdom
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17
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Qiu S, Liu Y, Li Q. A mechanism for localized dynamics-driven activation in Bruton's tyrosine kinase. ROYAL SOCIETY OPEN SCIENCE 2021; 8:210066. [PMID: 34457331 PMCID: PMC8371364 DOI: 10.1098/rsos.210066] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/24/2021] [Accepted: 07/19/2021] [Indexed: 05/28/2023]
Abstract
Bruton's tyrosine kinase (BTK) plays a vital role in mature B-cell proliferation, development and function. Its inhibitors have gradually been applied for the treatment of many B-cell malignancies. However, because of treatment-associated drug resistance or low efficacy, it is urgent to develop new inhibitors and/or improve the efficacy of current inhibitors, where finding the intrinsic activation mechanism becomes the key to solve this problem. Here, we used BTK T474M mutation as a resistance model for inhibitors to study the mechanism of BTK activation and drug resistance by free molecular dynamics simulations. The results showed that the increase of kinase activity of T474M mutation is coming from the conformation change of the activation ring and ATP binding sites located in BTK N-terminus region. Specifically, the Thr474 mutation changed the structure of A-loop and stabilized the binding site of ATP, thus promoting the catalytic ability in the kinase domain. This localized dynamics-driven activation mechanism and resistance mechanism of BTK may provide new ideas for drug development in B-cell malignancies.
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Affiliation(s)
- Simei Qiu
- Institute of Biomechanics/School of Bioscience and Bioengineering, South China University of Technology, Guangzhou People's Republic of China
- Guangdong Provincial Engineering and Technology Research Center of Biopharmaceuticals, South China University of Technology, Guangzhou People's Republic of China
| | - Yunfeng Liu
- Institute of Biomechanics/School of Bioscience and Bioengineering, South China University of Technology, Guangzhou People's Republic of China
| | - Quhuan Li
- Institute of Biomechanics/School of Bioscience and Bioengineering, South China University of Technology, Guangzhou People's Republic of China
- Guangdong Provincial Engineering and Technology Research Center of Biopharmaceuticals, South China University of Technology, Guangzhou People's Republic of China
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18
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Kueffer LE, Joseph RE, Andreotti AH. Reining in BTK: Interdomain Interactions and Their Importance in the Regulatory Control of BTK. Front Cell Dev Biol 2021; 9:655489. [PMID: 34249912 PMCID: PMC8260988 DOI: 10.3389/fcell.2021.655489] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2021] [Accepted: 06/02/2021] [Indexed: 12/22/2022] Open
Abstract
Since Dr. Ogden Bruton's 1952 paper describing the first human primary immunodeficiency disease, the peripheral membrane binding signaling protein, aptly named Bruton's tyrosine kinase (BTK), has been the target of intense study. Dr. Bruton's description of agammaglobulinemia set the stage for ultimately understanding key signaling steps emanating from the B cell receptor. BTK is a multidomain tyrosine kinase and in the decades since Dr. Bruton's discovery it has become clear that genetic defects in the regulatory domains or the catalytic domain can lead to immunodeficiency. This finding underscores the intricate regulatory mechanisms within the BTK protein that maintain appropriate levels of signaling both in the resting B cell and during an immune challenge. In recent decades, BTK has become a target for clinical intervention in treating B cell malignancies. The survival reliance of B cell malignancies on B cell receptor signaling has allowed small molecules that target BTK to become essential tools in treating patients with hematological malignancies. The first-in-class Ibrutinib and more selective second-generation inhibitors all target the active site of the multidomain BTK protein. Therapeutic interventions targeting BTK have been successful but are plagued by resistance mutations that render drug treatment ineffective for some patients. This review will examine the molecular mechanisms that drive drug resistance, the long-range conformational effects of active site inhibitors on the BTK regulatory apparatus, and emerging opportunities to allosterically target the BTK kinase to improve therapeutic interventions using combination therapies.
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Affiliation(s)
| | | | - Amy H. Andreotti
- Roy J. Carver Department of Biochemistry, Biophysics and Molecular Biology, Iowa State University, Ames, IA, United States
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19
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Grassilli E, Cerrito MG, Bonomo S, Giovannoni R, Conconi D, Lavitrano M. p65BTK Is a Novel Biomarker and Therapeutic Target in Solid Tumors. Front Cell Dev Biol 2021; 9:690365. [PMID: 34164404 PMCID: PMC8215537 DOI: 10.3389/fcell.2021.690365] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2021] [Accepted: 05/07/2021] [Indexed: 12/30/2022] Open
Abstract
Bruton’s tyrosine kinase (BTK) is a non-receptor intracellular kinase playing a key role in the proliferation and survival of normal and malignant B-lymphocytes. Its targeting by Ibrutinib, the first specific inhibitor, represented a turning point for the therapy of certain types of B-cell leukemias/lymphomas and several more BTK inhibitors are today in the clinic or advanced clinical trials. BTK expression was successively found to occur also outside of the hematopoietic compartment. In fact, we identified p65BTK, a novel 65 kDa isoform lacking an N-term stretch of 86 amino acids (compared to the 77 kDa protein expressed in B cells) as highly expressed in colon cancer patients. We demonstrated that p65BTK is a powerful oncogene acting downstream of the RAS/MAPK pathway and necessary for RAS-mediated transformation. Notably, the kinase domain is conserved and therefore inhibited by the available BTK-targeting drugs (Ibrutinib, Spebrutinib, etc.) which we used to demonstrate that p65BTK is an actionable target in drug-resistant colorectal carcinomas. We found p65BTK expressed also in >50% non-small cell lung cancers (NSCLC) and demonstrated that it is an actionable target in KRAS-mutated/EGFR-wild type drug-resistant NSCLC models (for which no targeted therapy is available). We also reported a significant correlation between p65BTK expression and low-grade tumors and overall survival of patients with grade III gliomas and showed that its targeting induced a significant decrease in the viability of in glioma stem cells. Finally, in ovarian cancer patients, p65BTK expression levels correlate with early relapse and shorter progression-free survival, both indicators of resistance to therapy. Remarkably, Ibrutinib is more effective than standard of care (SOC) therapeutics in in vitro and ex vivo settings. On the whole, our preclinical data indicate that, depending on the tumor type, BTK inhibitors used alone can induce cytotoxicity (gliomas), be more effective than SOC chemotherapy (ovarian cancer) or can kill drug-resistant tumor cells when used in combination with SOC chemotherapy (colon cancer and NSCLC) or targeted therapy (NSCLC and ovarian cancer), thus suggesting that p65BTK may be an actionable target in different solid tumors. In addition, our data also give the proof-of-concept for starting clinical trials using BTK inhibitors, alone or in combination, to improve the therapeutic options for solid tumors treatment.
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Affiliation(s)
- Emanuela Grassilli
- Laboratory of Molecular Medicine, Department of Medicine and Surgery, University of Milano-Bicocca, Monza, Italy
| | - Maria Grazia Cerrito
- Laboratory of Molecular Medicine, Department of Medicine and Surgery, University of Milano-Bicocca, Monza, Italy
| | - Sara Bonomo
- Laboratory of Molecular Medicine, Department of Medicine and Surgery, University of Milano-Bicocca, Monza, Italy
| | - Roberto Giovannoni
- Laboratory of Molecular Medicine, Department of Medicine and Surgery, University of Milano-Bicocca, Monza, Italy
| | - Donatella Conconi
- Laboratory of Molecular Medicine, Department of Medicine and Surgery, University of Milano-Bicocca, Monza, Italy
| | - Marialuisa Lavitrano
- Laboratory of Molecular Medicine, Department of Medicine and Surgery, University of Milano-Bicocca, Monza, Italy
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20
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Cerrito MG, Grassilli E. Identifying Novel Actionable Targets in Colon Cancer. Biomedicines 2021; 9:biomedicines9050579. [PMID: 34065438 PMCID: PMC8160963 DOI: 10.3390/biomedicines9050579] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2021] [Revised: 05/10/2021] [Accepted: 05/14/2021] [Indexed: 02/07/2023] Open
Abstract
Colorectal cancer is the fourth cause of death from cancer worldwide, mainly due to the high incidence of drug-resistance toward classic chemotherapeutic and newly targeted drugs. In the last decade or so, the development of novel high-throughput approaches, both genome-wide and chemical, allowed the identification of novel actionable targets and the development of the relative specific inhibitors to be used either to re-sensitize drug-resistant tumors (in combination with chemotherapy) or to be synthetic lethal for tumors with specific oncogenic mutations. Finally, high-throughput screening using FDA-approved libraries of “known” drugs uncovered new therapeutic applications of drugs (used alone or in combination) that have been in the clinic for decades for treating non-cancerous diseases (re-positioning or re-purposing approach). Thus, several novel actionable targets have been identified and some of them are already being tested in clinical trials, indicating that high-throughput approaches, especially those involving drug re-positioning, may lead in a near future to significant improvement of the therapy for colon cancer patients, especially in the context of a personalized approach, i.e., in defined subgroups of patients whose tumors carry certain mutations.
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21
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Jepson TA, Chung JK. Diffusion-based determination of protein homodimerization on reconstituted membrane surfaces. BMB Rep 2021. [PMID: 33408000 PMCID: PMC8016661 DOI: 10.5483/bmbrep.2021.54.3.228] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022] Open
Abstract
The transient interactions between cellular components, particularly on membrane surfaces, are critical in the proper function of many biochemical reactions. For example, many signaling pathways involve dimerization, oligomerization, or other types of clustering of signaling proteins as a key step in the signaling cascade. However, it is often experimentally challenging to directly observe and characterize the molecular mechanisms such interactions—the greatest difficulty lies in the fact that living cells have an unknown number of background processes that may or may not participate in the molecular process of interest, and as a consequence, it is usually impossible to definitively correlate an observation to a well-defined cellular mechanism. One of the experimental methods that can quantitatively capture these interactions is through membrane reconstitution, whereby a lipid bilayer is fabricated to mimic the membrane environment, and the biological components of interest are systematically introduced, without unknown background processes. This configuration allows the extensive use of fluorescence techniques, particularly fluorescence fluctuation spectroscopy and single-molecule fluorescence microscopy. In this review, we describe how the equilibrium diffusion of two proteins, K-Ras4B and the PH domain of Bruton’s tyrosine kinase (Btk), on fluid lipid membranes can be used to determine the kinetics of homodimerization reactions.
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Affiliation(s)
- Tyler A. Jepson
- Department of Chemistry, Colorado State University, Fort Collins, CO 80523, USA
| | - Jean K. Chung
- Department of Chemistry, Colorado State University, Fort Collins, CO 80523, USA
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22
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Joseph RE, Amatya N, Fulton DB, Engen JR, Wales TE, Andreotti A. Differential impact of BTK active site inhibitors on the conformational state of full-length BTK. eLife 2020; 9:60470. [PMID: 33226337 PMCID: PMC7834017 DOI: 10.7554/elife.60470] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2020] [Accepted: 11/20/2020] [Indexed: 12/30/2022] Open
Abstract
Bruton’s tyrosine kinase (BTK) is targeted in the treatment of B-cell disorders including leukemias and lymphomas. Currently approved BTK inhibitors, including Ibrutinib, a first-in-class covalent inhibitor of BTK, bind directly to the kinase active site. While effective at blocking the catalytic activity of BTK, consequences of drug binding on the global conformation of full-length BTK are unknown. Here, we uncover a range of conformational effects in full-length BTK induced by a panel of active site inhibitors, including large-scale shifts in the conformational equilibria of the regulatory domains. Additionally, we find that a remote Ibrutinib resistance mutation, T316A in the BTK SH2 domain, drives spurious BTK activity by destabilizing the compact autoinhibitory conformation of full-length BTK, shifting the conformational ensemble away from the autoinhibited form. Future development of BTK inhibitors will need to consider long-range allosteric consequences of inhibitor binding, including the emerging application of these BTK inhibitors in treating COVID-19. Treatments for blood cancers, such as leukemia and lymphoma, rely heavily on chemotherapy, using drugs that target a vulnerable aspect of the cancer cells. B-cells, a type of white blood cell that produces antibodies, require a protein called Bruton’s tyrosine kinase, or BTK for short, to survive. The drug ibrutinib (Imbruvica) is used to treat B-cell cancers by blocking BTK. The BTK protein consists of several regions. One of them, known as the kinase domain, is responsible for its activity as an enzyme (which allows it to modify other proteins by adding a ‘tag’ known as a phosphate group). The other regions of BTK, known as regulatory modules, control this activity. In BTK’s inactive form, the regulatory modules attach to the kinase domain, blocking the regulatory modules from interacting with other proteins. When BTK is activated, it changes its conformation so the regulatory regions detach and become available for interactions with other proteins, at the same time exposing the active kinase domain. Ibrutinib and other BTK drugs in development bind to the kinase domain to block its activity. However, it is not known how this binding affects the regulatory modules. Previous efforts to study how drugs bind to BTK have used a version of the protein that only had the kinase domain, instead of the full-length protein. Now, Joseph et al. have studied full-length BTK and how it binds to five different drugs. The results reveal that ibrutinib and another drug called dasatinib both indirectly disrupt the normal position of the regulatory domains pushing BTK toward a conformation that resembles the activated state. By contrast, the three other compounds studied do not affect the inactive structure. Joseph et al. also examined a mutation in BTK that confers resistance against ibrutinib. This mutation increases the activity of BTK by disrupting the inactive structure, leading to B cells surviving better. Understanding how drug resistance mechanisms can work will lead to better drug treatment strategies for cancer. BTK is also a target in other diseases such as allergies or asthma and even COVID-19. If interactions between partner proteins and the regulatory domain are important in these diseases, then they may be better treated with drugs that maintain the regulatory modules in their inactive state. This research will help to design drugs that are better able to control BTK activity.
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Affiliation(s)
- Raji E Joseph
- Roy J. Carver Department of Biochemistry, Biophysics and Molecular Biology, Iowa State University, Ames, United States
| | - Neha Amatya
- Roy J. Carver Department of Biochemistry, Biophysics and Molecular Biology, Iowa State University, Ames, United States
| | - D Bruce Fulton
- Roy J. Carver Department of Biochemistry, Biophysics and Molecular Biology, Iowa State University, Ames, United States
| | - John R Engen
- Department of Chemistry and Chemical Biology, Northeastern University, Boston, United States
| | - Thomas E Wales
- Department of Chemistry and Chemical Biology, Northeastern University, Boston, United States
| | - Amy Andreotti
- Roy J. Carver Department of Biochemistry, Biophysics and Molecular Biology, Iowa State University, Ames, United States
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23
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Btk SH2-kinase interface is critical for allosteric kinase activation and its targeting inhibits B-cell neoplasms. Nat Commun 2020; 11:2319. [PMID: 32385234 PMCID: PMC7210950 DOI: 10.1038/s41467-020-16128-5] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2020] [Accepted: 04/15/2020] [Indexed: 02/07/2023] Open
Abstract
Bruton’s tyrosine kinase (Btk) is critical for B-cell maturation and activation. Btk loss-of-function mutations cause human X-linked agammaglobulinemia (XLA). In contrast, Btk signaling sustains growth of several B-cell neoplasms which may be treated with tyrosine kinase inhibitors (TKIs). Here, we uncovered the structural mechanism by which certain XLA mutations in the SH2 domain strongly perturb Btk activation. Using a combination of molecular dynamics (MD) simulations and small-angle X-ray scattering (SAXS), we discovered an allosteric interface between the SH2 and kinase domain required for Btk activation and to which multiple XLA mutations map. As allosteric interactions provide unique targeting opportunities, we developed an engineered repebody protein binding to the SH2 domain and able to disrupt the SH2-kinase interaction. The repebody prevents activation of wild-type and TKI-resistant Btk, inhibiting Btk-dependent signaling and proliferation of malignant B-cells. Therefore, the SH2-kinase interface is critical for Btk activation and a targetable site for allosteric inhibition. Constitutive Btk signaling drives several B-cell cancers. Here the authors demonstrate key allosteric intramolecular interactions between the SH2 domain and the kinase domain of Btk, and propose an alternative approach for inhibition of both wild-type and tyrosine kinase inhibitor-resistant Btk.
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Jeong S, Sohn YK, Choi Y, Park J, Kim HS. A regulatory SH2 domain-targeting protein binder effectively inhibits the activity of Bruton's tyrosine kinase and its drug-resistant variants. Biochem Biophys Res Commun 2020; 526:8-13. [PMID: 32192770 DOI: 10.1016/j.bbrc.2020.03.006] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2020] [Accepted: 03/03/2020] [Indexed: 01/06/2023]
Abstract
Human Bruton's tyrosine kinase (hBtk) plays a key role in growth and metabolism of B cells, but its dysfunctions cause various B-cell malignancies. Inhibitors targeting the ATP-binding pocket of hBtk have been developed, but they have several drawbacks such as adverse side effects and occurrence of drug-resistant mutations. Here, we present a protein binder which specifically binds to an allosteric regulatory SH2 domain of hBtk. The protein binder effectively inhibited the hBtk activity, indicating a critical role of the SH2 domain in allosteric regulation of the hBtk activity. Cytosolic delivery of the protein binder led to a significant inhibition on the BCR-mediated signaling and viability of B lymphoma cells. The utility of our approach was demonstrated by effective inhibition of drug-resistant hBtk variants by the protein binder. Based on the computationally predicted binding mode, the protein binder is likely to inhibit the hBtk activity by disrupting the interaction between the SH2 domain and kinase domain. The present approach can be used for developing therapeutic agents with improved efficacy for B-cell lymphoma.
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Affiliation(s)
- Sukyo Jeong
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 34141, South Korea
| | - Yoo-Kyoung Sohn
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 34141, South Korea
| | - Yoonjoo Choi
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 34141, South Korea
| | - Jinho Park
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 34141, South Korea
| | - Hak-Sung Kim
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 34141, South Korea.
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25
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Hammond GRV, Burke JE. Novel roles of phosphoinositides in signaling, lipid transport, and disease. Curr Opin Cell Biol 2020; 63:57-67. [PMID: 31972475 DOI: 10.1016/j.ceb.2019.12.007] [Citation(s) in RCA: 97] [Impact Index Per Article: 24.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2019] [Revised: 12/12/2019] [Accepted: 12/14/2019] [Indexed: 12/22/2022]
Abstract
Phosphoinositides (PPIns) are lipid signaling molecules that act as master regulators of cellular signaling. Recent studies have revealed novel roles of PPIns in myriad cellular processes and multiple human diseases mediated by misregulation of PPIn signaling. This review will present a timely summary of recent discoveries in PPIn biology, specifically their role in regulating unexpected signaling pathways, modification of signaling outcomes downstream of integral membrane proteins, and novel roles in lipid transport. This has revealed new roles of PPIns in regulating membrane trafficking, immunity, cell polarity, and response to extracellular signals. A specific focus will be on novel opportunities to target PPIn metabolism for treatment of human diseases, including cancer, pathogen infection, developmental disorders, and immune disorders.
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Affiliation(s)
- Gerald R V Hammond
- Department of Cell Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA, 15261, USA.
| | - John E Burke
- Department of Biochemistry and Microbiology, University of Victoria, Victoria, British Columbia, V8W 2Y2, Canada.
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26
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Lavitrano M, Ianzano L, Bonomo S, Cialdella A, Cerrito MG, Pisano F, Missaglia C, Giovannoni R, Romano G, McLean CM, Voest EE, D'Amato F, Noli B, Ferri GL, Agostini M, Pucciarelli S, Helin K, Leone BE, Canzonieri V, Grassilli E. BTK inhibitors synergise with 5-FU to treat drug-resistant TP53-null colon cancers. J Pathol 2019; 250:134-147. [PMID: 31518438 DOI: 10.1002/path.5347] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2019] [Revised: 08/05/2019] [Accepted: 09/10/2019] [Indexed: 12/12/2022]
Abstract
Colorectal cancer (CRC) is the fourth cause of death from cancer worldwide mainly due to the high incidence of drug-resistance. During a screen for new actionable targets in drug-resistant tumours we recently identified p65BTK - a novel oncogenic isoform of Bruton's tyrosine kinase. Studying three different cohorts of patients here we show that p65BTK expression correlates with histotype and cancer progression. Using drug-resistant TP53-null colon cancer cells as a model we demonstrated that p65BTK silencing or chemical inhibition overcame the 5-fluorouracil resistance of CRC cell lines and patient-derived organoids and significantly reduced the growth of xenografted tumours. Mechanistically, we show that blocking p65BTK in drug-resistant cells abolished a 5-FU-elicited TGFB1 protective response and triggered E2F-dependent apoptosis. Taken together, our data demonstrated that targeting p65BTK restores the apoptotic response to chemotherapy of drug-resistant CRCs and gives a proof-of-concept for suggesting the use of BTK inhibitors in combination with 5-FU as a novel therapeutic approach in CRC patients. © 2019 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
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Affiliation(s)
| | - Leonarda Ianzano
- School of Medicine and Surgery, University of Milano-Bicocca, Monza, Italy
| | - Sara Bonomo
- School of Medicine and Surgery, University of Milano-Bicocca, Monza, Italy
| | | | | | - Fabio Pisano
- School of Medicine and Surgery, University of Milano-Bicocca, Monza, Italy
| | - Carola Missaglia
- School of Medicine and Surgery, University of Milano-Bicocca, Monza, Italy
| | - Roberto Giovannoni
- School of Medicine and Surgery, University of Milano-Bicocca, Monza, Italy
| | - Gabriele Romano
- School of Medicine and Surgery, University of Milano-Bicocca, Monza, Italy
| | - Chelsea M McLean
- Department of Molecular Oncology and Immunology, The Netherlands Cancer Institute, Amsterdam, The Netherlands
| | - Emile E Voest
- Department of Molecular Oncology and Immunology, The Netherlands Cancer Institute, Amsterdam, The Netherlands
| | - Filomena D'Amato
- NEF-Laboratory, Department of Biomedical Science, University of Cagliari, Cagliari, Italy
| | - Barbara Noli
- NEF-Laboratory, Department of Biomedical Science, University of Cagliari, Cagliari, Italy
| | - Gian Luca Ferri
- NEF-Laboratory, Department of Biomedical Science, University of Cagliari, Cagliari, Italy
| | - Marco Agostini
- First Surgical Clinic Section, Department of Surgery, Oncology and Gastroenterology, University of Padova, Padova, Italy.,Department of Nanomedicine, The Methodist Hospital Research Institute, Houston, TX, USA
| | - Salvatore Pucciarelli
- First Surgical Clinic Section, Department of Surgery, Oncology and Gastroenterology, University of Padova, Padova, Italy
| | - Kristian Helin
- Center for Epigenetics, Sloan Kettering Institute, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Biagio E Leone
- School of Medicine and Surgery, University of Milano-Bicocca, Monza, Italy
| | - Vincenzo Canzonieri
- Pathology Unit and CRO Biobank, CRO Aviano National Cancer Institute, Aviano, Italy
| | - Emanuela Grassilli
- School of Medicine and Surgery, University of Milano-Bicocca, Monza, Italy
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Lipid-targeting pleckstrin homology domain turns its autoinhibitory face toward the TEC kinases. Proc Natl Acad Sci U S A 2019; 116:21539-21544. [PMID: 31591208 PMCID: PMC6815127 DOI: 10.1073/pnas.1907566116] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Bruton’s tyrosine kinase (BTK) is targeted in treatment of immune cancers. As patients experience drug resistance, there is a need for alternative approaches to inhibit BTK. Other recently published findings clarify the role of the BTK pleckstrin homology (PH) domain in mediating activation via dimerization and sensing of ligand concentration at the membrane. Work presented here provides insight into the autoinhibitory BTK structure that has so far been elusive via crystallographic methods. In the resting state, the BTK PH domain binds to the activation loop face of the kinase domain and allosterically alters key sites within the kinase domain. The findings define a new regulatory site, the PH/kinase interface, that can be exploited in drug discovery efforts. The pleckstrin homology (PH) domain is well known for its phospholipid targeting function. The PH-TEC homology (PHTH) domain within the TEC family of tyrosine kinases is also a crucial component of the autoinhibitory apparatus. The autoinhibitory surface on the PHTH domain has been previously defined, and biochemical investigations have shown that PHTH-mediated inhibition is mutually exclusive with phosphatidylinositol binding. Here we use hydrogen/deuterium exchange mass spectrometry, nuclear magnetic resonance (NMR), and evolutionary sequence comparisons to map where and how the PHTH domain affects the Bruton’s tyrosine kinase (BTK) domain. The data map a PHTH-binding site on the activation loop face of the kinase C lobe, suggesting that the PHTH domain masks the activation loop and the substrate-docking site. Moreover, localized NMR spectral changes are observed for non–surface-exposed residues in the active site and on the distal side of the kinase domain. These data suggest that the association of PHTH induces allosteric conformational shifts in regions of the kinase domain that are critical for catalysis. Through statistical comparisons of diverse tyrosine kinase sequences, we identify residues unique to BTK that coincide with the experimentally determined PHTH-binding surface on the kinase domain. Our data provide a more complete picture of the autoinhibitory conformation adopted by full-length TEC kinases, creating opportunities to target the regulatory domains to control the function of these kinases in a biological setting.
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Dynamic regulatory features of the protein tyrosine kinases. Biochem Soc Trans 2019; 47:1101-1116. [PMID: 31395755 DOI: 10.1042/bst20180590] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2019] [Revised: 07/15/2019] [Accepted: 07/17/2019] [Indexed: 12/20/2022]
Abstract
The SRC, Abelson murine leukemia viral oncogene homolog 1, TEC and C-terminal SRC Kinase families of non-receptor tyrosine kinases (collectively the Src module kinases) mediate an array of cellular signaling processes and are therapeutic targets in many disease states. Crystal structures of Src modules kinases provide valuable insights into the regulatory mechanisms that control activation and generate a framework from which drug discovery can advance. The conformational ensembles visited by these multidomain kinases in solution are also key features of the regulatory machinery controlling catalytic activity. Measurement of dynamic motions within kinases substantially augments information derived from crystal structures. In this review, we focus on a body of work that has transformed our understanding of non-receptor tyrosine kinase regulation from a static view to one that incorporates how fluctuations in conformational ensembles and dynamic motions influence activation status. Regulatory dynamic networks are often shared across and between kinase families while specific dynamic behavior distinguishes unique regulatory mechanisms for select kinases. Moreover, intrinsically dynamic regions of kinases likely play important regulatory roles that have only been partially explored. Since there is clear precedence that kinase inhibitors can exploit specific dynamic features, continued efforts to define conformational ensembles and dynamic allostery will be key to combating drug resistance and devising alternate treatments for kinase-associated diseases.
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Andreotti AH, Joseph RE, Conley JM, Iwasa J, Berg LJ. Multidomain Control Over TEC Kinase Activation State Tunes the T Cell Response. Annu Rev Immunol 2019; 36:549-578. [PMID: 29677469 DOI: 10.1146/annurev-immunol-042617-053344] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Signaling through the T cell antigen receptor (TCR) activates a series of tyrosine kinases. Directly associated with the TCR, the SRC family kinase LCK and the SYK family kinase ZAP-70 are essential for all downstream responses to TCR stimulation. In contrast, the TEC family kinase ITK is not an obligate component of the TCR cascade. Instead, ITK functions as a tuning dial, to translate variations in TCR signal strength into differential programs of gene expression. Recent insights into TEC kinase structure have provided a view into the molecular mechanisms that generate different states of kinase activation. In resting lymphocytes, TEC kinases are autoinhibited, and multiple interactions between the regulatory and kinase domains maintain low activity. Following TCR stimulation, newly generated signaling modules compete with the autoinhibited core and shift the conformational ensemble to the fully active kinase. This multidomain control over kinase activation state provides a structural mechanism to account for ITK's ability to tune the TCR signal.
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Affiliation(s)
- Amy H Andreotti
- Roy J. Carver Department of Biochemistry, Biophysics and Molecular Biology, Iowa State University, Ames, Iowa 50011, USA; ,
| | - Raji E Joseph
- Roy J. Carver Department of Biochemistry, Biophysics and Molecular Biology, Iowa State University, Ames, Iowa 50011, USA; ,
| | - James M Conley
- Department of Pathology, University of Massachusetts Medical School, Worcester, Massachusetts 01655, USA; ,
| | - Janet Iwasa
- Department of Biochemistry, University of Utah, Salt Lake City, Utah 84112, USA;
| | - Leslie J Berg
- Department of Pathology, University of Massachusetts Medical School, Worcester, Massachusetts 01655, USA; ,
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30
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Abstract
Bruton’s tyrosine kinase (Btk) activation on the cell membrane is critical for B cell proliferation and development, and Btk inhibition is a promising treatment for several hematologic cancers and autoimmune diseases. Here, we examine Btk activation using the results of long-timescale molecular dynamics simulations. In our simulations, Btk lipid-binding modules dimerized on the membrane in a single predominant conformation. We observed that the phospholipid PIP3—in addition to its expected role of recruiting Btk to the membrane—allosterically mediated dimer formation and stability by binding at two novel sites. Our results provide strong evidence that PIP3-mediated dimerization of Btk at the cell membrane is a critical step in Btk activation and suggest a potential approach to allosteric Btk inhibitor development. Bruton’s tyrosine kinase (Btk) is critical for B cell proliferation and activation, and the development of Btk inhibitors is a vigorously pursued strategy for the treatment of various B cell malignancies. A detailed mechanistic understanding of Btk activation has, however, been lacking. Here, inspired by a previous suggestion that Btk activation might depend on dimerization of its lipid-binding PH–TH module on the cell membrane, we performed long-timescale molecular dynamics simulations of membrane-bound PH–TH modules and observed that they dimerized into a single predominant conformation. We found that the phospholipid PIP3 stabilized the dimer allosterically by binding at multiple sites, and that the effects of PH–TH mutations on dimer stability were consistent with their known effects on Btk activity. Taken together, our simulation results strongly suggest that PIP3-mediated dimerization of Btk at the cell membrane is a critical step in Btk activation.
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A Combined Approach Reveals a Regulatory Mechanism Coupling Src's Kinase Activity, Localization, and Phosphotransferase-Independent Functions. Mol Cell 2019; 74:393-408.e20. [PMID: 30956043 DOI: 10.1016/j.molcel.2019.02.003] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2018] [Revised: 11/20/2018] [Accepted: 01/31/2019] [Indexed: 02/06/2023]
Abstract
Multiple layers of regulation modulate the activity and localization of protein kinases. However, many details of kinase regulation remain incompletely understood. Here, we apply saturation mutagenesis and a chemical genetic method for allosterically modulating kinase global conformation to Src kinase, providing insight into known regulatory mechanisms and revealing a previously undiscovered interaction between Src's SH4 and catalytic domains. Abrogation of this interaction increased phosphotransferase activity, promoted membrane association, and provoked phosphotransferase-independent alterations in cell morphology. Thus, Src's SH4 domain serves as an intramolecular regulator coupling catalytic activity, global conformation, and localization, as well as mediating a phosphotransferase-independent function. Sequence conservation suggests that the SH4 domain regulatory interaction exists in other Src-family kinases. Our combined approach's ability to reveal a regulatory mechanism in one of the best-studied kinases suggests that it could be applied broadly to provide insight into kinase structure, regulation, and function.
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Pemberton JG, Balla T. Polyphosphoinositide-Binding Domains: Insights from Peripheral Membrane and Lipid-Transfer Proteins. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2019; 1111:77-137. [PMID: 30483964 DOI: 10.1007/5584_2018_288] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Within eukaryotic cells, biochemical reactions need to be organized on the surface of membrane compartments that use distinct lipid constituents to dynamically modulate the functions of integral proteins or influence the selective recruitment of peripheral membrane effectors. As a result of these complex interactions, a variety of human pathologies can be traced back to improper communication between proteins and membrane surfaces; either due to mutations that directly alter protein structure or as a result of changes in membrane lipid composition. Among the known structural lipids found in cellular membranes, phosphatidylinositol (PtdIns) is unique in that it also serves as the membrane-anchored precursor of low-abundance regulatory lipids, the polyphosphoinositides (PPIn), which have restricted distributions within specific subcellular compartments. The ability of PPIn lipids to function as signaling platforms relies on both non-specific electrostatic interactions and the selective stereospecific recognition of PPIn headgroups by specialized protein folds. In this chapter, we will attempt to summarize the structural diversity of modular PPIn-interacting domains that facilitate the reversible recruitment and conformational regulation of peripheral membrane proteins. Outside of protein folds capable of capturing PPIn headgroups at the membrane interface, recent studies detailing the selective binding and bilayer extraction of PPIn species by unique functional domains within specific families of lipid-transfer proteins will also be highlighted. Overall, this overview will help to outline the fundamental physiochemical mechanisms that facilitate localized interactions between PPIn lipids and the wide-variety of PPIn-binding proteins that are essential for the coordinate regulation of cellular metabolism and membrane dynamics.
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Affiliation(s)
- Joshua G Pemberton
- Section on Molecular Signal Transduction, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA
| | - Tamas Balla
- Section on Molecular Signal Transduction, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA.
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Shah NH, Amacher JF, Nocka LM, Kuriyan J. The Src module: an ancient scaffold in the evolution of cytoplasmic tyrosine kinases. Crit Rev Biochem Mol Biol 2018; 53:535-563. [PMID: 30183386 PMCID: PMC6328253 DOI: 10.1080/10409238.2018.1495173] [Citation(s) in RCA: 49] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Tyrosine kinases were first discovered as the protein products of viral oncogenes. We now know that this large family of metazoan enzymes includes nearly one hundred structurally diverse members. Tyrosine kinases are broadly classified into two groups: the transmembrane receptor tyrosine kinases, which sense extracellular stimuli, and the cytoplasmic tyrosine kinases, which contain modular ligand-binding domains and propagate intracellular signals. Several families of cytoplasmic tyrosine kinases have in common a core architecture, the "Src module," composed of a Src-homology 3 (SH3) domain, a Src-homology 2 (SH2) domain, and a kinase domain. Each of these families is defined by additional elaborations on this core architecture. Structural, functional, and evolutionary studies have revealed a unifying set of principles underlying the activity and regulation of tyrosine kinases built on the Src module. The discovery of these conserved properties has shaped our knowledge of the workings of protein kinases in general, and it has had important implications for our understanding of kinase dysregulation in disease and the development of effective kinase-targeted therapies.
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Affiliation(s)
- Neel H. Shah
- Department of Molecular and Cell Biology, University of California, Berkeley, CA, USA
- Department of Chemistry, University of California, Berkeley, CA, USA
- California Institute for Quantitative Biosciences, University of California, Berkeley, CA, USA
- Howard Hughes Medical Institute, University of California, Berkeley, CA, USA
| | - Jeanine F. Amacher
- Department of Molecular and Cell Biology, University of California, Berkeley, CA, USA
- Department of Chemistry, University of California, Berkeley, CA, USA
- California Institute for Quantitative Biosciences, University of California, Berkeley, CA, USA
- Howard Hughes Medical Institute, University of California, Berkeley, CA, USA
| | - Laura M. Nocka
- Department of Molecular and Cell Biology, University of California, Berkeley, CA, USA
- Department of Chemistry, University of California, Berkeley, CA, USA
- California Institute for Quantitative Biosciences, University of California, Berkeley, CA, USA
- Howard Hughes Medical Institute, University of California, Berkeley, CA, USA
| | - John Kuriyan
- Department of Molecular and Cell Biology, University of California, Berkeley, CA, USA
- Department of Chemistry, University of California, Berkeley, CA, USA
- California Institute for Quantitative Biosciences, University of California, Berkeley, CA, USA
- Howard Hughes Medical Institute, University of California, Berkeley, CA, USA
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
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Hanson QM, Carley JR, Gilbreath TJ, Smith BC, Underbakke ES. Calmodulin-induced Conformational Control and Allostery Underlying Neuronal Nitric Oxide Synthase Activation. J Mol Biol 2018; 430:935-947. [PMID: 29458127 DOI: 10.1016/j.jmb.2018.02.003] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2017] [Revised: 02/07/2018] [Accepted: 02/07/2018] [Indexed: 10/18/2022]
Abstract
Nitric oxide synthase (NOS) is the primary generator of nitric oxide signals controlling diverse physiological processes such as neurotransmission and vasodilation. NOS activation is contingent on Ca2+/calmodulin binding at a linker between its oxygenase and reductase domains to induce large conformational changes that orchestrate inter-domain electron transfer. However, the structural dynamics underlying activation of full-length NOS remain ambiguous. Employing hydrogen-deuterium exchange mass spectrometry, we reveal mechanisms underlying neuronal NOS activation by calmodulin and regulation by phosphorylation. We demonstrate that calmodulin binding orders the junction between reductase and oxygenase domains, exposes the FMN subdomain, and elicits a more dynamic oxygenase active site. Furthermore, we demonstrate that phosphorylation partially mimics calmodulin activation to modulate neuronal NOS activity via long-range allostery. Calmodulin binding and phosphorylation ultimately promote a more dynamic holoenzyme while coordinating inter-domain communication and electron transfer.
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Affiliation(s)
- Quinlin M Hanson
- Roy J. Carver Department of Biochemistry, Biophysics, and Molecular Biology, Iowa State University, Ames, IA 50011, USA
| | - Jeffrey R Carley
- Roy J. Carver Department of Biochemistry, Biophysics, and Molecular Biology, Iowa State University, Ames, IA 50011, USA
| | - Tyler J Gilbreath
- Roy J. Carver Department of Biochemistry, Biophysics, and Molecular Biology, Iowa State University, Ames, IA 50011, USA
| | - Brian C Smith
- Department of Biochemistry, Medical College of Wisconsin, Milwaukee, WI 53226, USA
| | - Eric S Underbakke
- Roy J. Carver Department of Biochemistry, Biophysics, and Molecular Biology, Iowa State University, Ames, IA 50011, USA.
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35
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Satterthwaite AB. Bruton's Tyrosine Kinase, a Component of B Cell Signaling Pathways, Has Multiple Roles in the Pathogenesis of Lupus. Front Immunol 2018; 8:1986. [PMID: 29403475 PMCID: PMC5786522 DOI: 10.3389/fimmu.2017.01986] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2017] [Accepted: 12/21/2017] [Indexed: 01/08/2023] Open
Abstract
Systemic lupus erythematosus (SLE) is an autoimmune disease characterized by the loss of adaptive immune tolerance to nucleic acid-containing antigens. The resulting autoantibodies form immune complexes that promote inflammation and tissue damage. Defining the signals that drive pathogenic autoantibody production is an important step in the development of more targeted therapeutic approaches for lupus, which is currently treated primarily with non-specific immunosuppression. Here, we review the contribution of Bruton’s tyrosine kinase (Btk), a component of B and myeloid cell signaling pathways, to disease in murine lupus models. Both gain- and loss-of-function genetic studies have revealed that Btk plays multiple roles in the production of autoantibodies. These include promoting the activation, plasma cell differentiation, and class switching of autoreactive B cells. Small molecule inhibitors of Btk are effective at reducing autoantibody levels, B cell activation, and kidney damage in several lupus models. These studies suggest that Btk may promote end-organ damage both by facilitating the production of autoantibodies and by mediating the inflammatory response of myeloid cells to these immune complexes. While Btk has not been associated with SLE in GWAS studies, SLE B cells display signaling defects in components both upstream and downstream of Btk consistent with enhanced activation of Btk signaling pathways. Taken together, these observations indicate that limiting Btk activity is critical for maintaining B cell tolerance and preventing the development of autoimmune disease. Btk inhibitors, generally well-tolerated and approved to treat B cell malignancy, may thus be a useful therapeutic approach for SLE.
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Affiliation(s)
- Anne B Satterthwaite
- Department of Internal Medicine, The University of Texas Southwestern Medical Center, Dallas, TX, United States.,Department of Immunology, The University of Texas Southwestern Medical Center, Dallas, TX, United States
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36
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Agnew C, Jura N. Switching on BTK-One Domain at a Time. Structure 2017; 25:1469-1470. [PMID: 28978404 DOI: 10.1016/j.str.2017.09.012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
BTK kinase activity is controlled by multiple inhibitory domains, whose coordinated mechanism of action is poorly understood. In this issue of Structure,Joseph et al. (2017) use solution-based approaches to characterize conformational changes associated with the binding of each inhibitory tether, revealing a multi-step activation process and a previously unknown C-terminal autoinhibitory latch.
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Affiliation(s)
- Christopher Agnew
- Cardiovascular Research Institute, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Natalia Jura
- Cardiovascular Research Institute, University of California, San Francisco, San Francisco, CA 94158, USA; Department of Cellular and Molecular Pharmacology, University of California, San Francisco, San Francisco, CA 94158, USA.
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