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Abraham BG, Haikarainen T, Vuorio J, Girych M, Virtanen AT, Kurttila A, Karathanasis C, Heilemann M, Sharma V, Vattulainen I, Silvennoinen O. Molecular basis of JAK2 activation in erythropoietin receptor and pathogenic JAK2 signaling. SCIENCE ADVANCES 2024; 10:eadl2097. [PMID: 38457493 PMCID: PMC10923518 DOI: 10.1126/sciadv.adl2097] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/09/2023] [Accepted: 02/06/2024] [Indexed: 03/10/2024]
Abstract
Janus kinase 2 (JAK2) mediates type I/II cytokine receptor signaling, but JAK2 is also activated by somatic mutations that cause hematological malignancies by mechanisms that are still incompletely understood. Quantitative superresolution microscopy (qSMLM) showed that erythropoietin receptor (EpoR) exists as monomers and dimerizes upon Epo stimulation or through the predominant JAK2 pseudokinase domain mutations (V617F, K539L, and R683S). Crystallographic analysis complemented by kinase activity analysis and atomic-level simulations revealed distinct pseudokinase dimer interfaces and activation mechanisms for the mutants: JAK V617F activity is driven by dimerization, K539L involves both increased receptor dimerization and kinase activity, and R683S prevents autoinhibition and increases catalytic activity and drives JAK2 equilibrium toward activation state through a wild-type dimer interface. Artificial intelligence-guided modeling and simulations revealed that the pseudokinase mutations cause differences in the pathogenic full-length JAK2 dimers, particularly in the FERM-SH2 domains. A detailed molecular understanding of mutation-driven JAK2 hyperactivation may enable novel therapeutic approaches to selectively target pathogenic JAK2 signaling.
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Affiliation(s)
| | - Teemu Haikarainen
- Faculty of Medicine and Health Technology, Tampere University, Tampere, Finland
- Fimlab Laboratories, Tampere, Finland
| | - Joni Vuorio
- Department of Physics, University of Helsinki, Helsinki, Finland
| | - Mykhailo Girych
- Department of Physics, University of Helsinki, Helsinki, Finland
| | - Anniina T. Virtanen
- Faculty of Medicine and Health Technology, Tampere University, Tampere, Finland
- Institute of Biotechnology, HiLIFE, University of Helsinki, Helsinki, Finland
| | - Antti Kurttila
- Faculty of Medicine and Health Technology, Tampere University, Tampere, Finland
| | - Christos Karathanasis
- Institute of Physical and Theoretical Chemistry, Goethe-University Frankfurt, Frankfurt, Germany
| | - Mike Heilemann
- Institute of Physical and Theoretical Chemistry, Goethe-University Frankfurt, Frankfurt, Germany
| | - Vivek Sharma
- Department of Physics, University of Helsinki, Helsinki, Finland
- Institute of Biotechnology, HiLIFE, University of Helsinki, Helsinki, Finland
| | - Ilpo Vattulainen
- Department of Physics, University of Helsinki, Helsinki, Finland
| | - Olli Silvennoinen
- Faculty of Medicine and Health Technology, Tampere University, Tampere, Finland
- Fimlab Laboratories, Tampere, Finland
- Institute of Biotechnology, HiLIFE, University of Helsinki, Helsinki, Finland
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Glassman CR, Tsutsumi N, Saxton RA, Lupardus PJ, Jude KM, Garcia KC. Structure of a Janus kinase cytokine receptor complex reveals the basis for dimeric activation. Science 2022; 376:163-169. [PMID: 35271300 PMCID: PMC9306331 DOI: 10.1126/science.abn8933] [Citation(s) in RCA: 72] [Impact Index Per Article: 36.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Cytokines signal through cell surface receptor dimers to initiate activation of intracellular Janus Kinases (JAKs). We report the 3.6-Å resolution cryo-EM structure of full-length JAK1 complexed with a cytokine receptor intracellular Box1/Box2 domain, captured as an activated homodimer bearing the Val→Phe (VF) mutation prevalent in myeloproliferative neoplasms. The seven domains of JAK1 form an extended structural unit whose dimerization is mediated by close-packed pseudokinase (PK) domains. The oncogenic VF mutation lies within the core of the JAK1 PK dimer interface, enhancing packing complementarity to facilitate ligand-independent activation. The C-terminal tyrosine kinase domains are poised to phosphorylate the receptor STAT-recruiting motifs projecting from the overhanging FERM-SH2 domains. Mapping of constitutively active JAK mutants supports a two-step allosteric activation mechanism and reveals new opportunities for selective therapeutic targeting of oncogenic JAK signaling.
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Affiliation(s)
- Caleb R Glassman
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Naotaka Tsutsumi
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, CA 94305, USA.,Howard Hughes Medical Institute, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Robert A Saxton
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, CA 94305, USA.,Howard Hughes Medical Institute, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Patrick J Lupardus
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Kevin M Jude
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, CA 94305, USA.,Howard Hughes Medical Institute, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - K Christopher Garcia
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, CA 94305, USA.,Howard Hughes Medical Institute, Stanford University School of Medicine, Stanford, CA 94305, USA.,Department of Structural Biology, Stanford University School of Medicine, Stanford, CA 94305, USA
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