Uncoupling JAK2 V617F activation from cytokine-induced signalling by modulation of JH2 αC helix
نویسندگان
چکیده
The mechanisms by which JAK2 is activated by the prevalent pseudokinase (JH2) V617F mutation in blood cancers remain elusive. Via structure-guided mutagenesis and transcriptional and functional assays, we identify a community of residues from the JH2 helix αC, SH2-JH2 linker and JH1 kinase domain that mediate V617F-induced activation. This circuit is broken by altering the charge of residues along the solvent-exposed face of the JH2 αC, which is predicted to interact with the SH2-JH2 linker and JH1. Mutations that remove negative charges or add positive charges, such as E596A/R, do not alter the JH2 V617F fold, as shown by the crystal structure of JH2 V617F E596A. Instead, they prevent kinase domain activation via modulation of the C-terminal residues of the SH2-JH2 linker. These results suggest strategies for selective V617F JAK2 inhibition, with preservation of wild-type function.
منابع مشابه
Ab Initio Modeling and Experimental Assessment of Janus Kinase 2 (JAK2) Kinase-Pseudokinase Complex Structure
The Janus Kinase 2 (JAK2) plays essential roles in transmitting signals from multiple cytokine receptors, and constitutive activation of JAK2 results in hematopoietic disorders and oncogenesis. JAK2 kinase activity is negatively regulated by its pseudokinase domain (JH2), where the gain-of-function mutation V617F that causes myeloproliferative neoplasms resides. In the absence of a crystal stru...
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JAK (Janus kinase) 2 plays a critical role in signal transduction through several cytokine receptors. JAKs contain a typical tyrosine kinase domain preceded by a pseudokinase [JH2 (JAK homology 2)] domain which has been considered to be catalytically inactive. Identification of activating mutations in the JH2 domain of JAK2 as the major cause for polycythaemia vera and other MPNs (myeloprolifer...
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The discovery of the highly prevalent activating JAK (Janus kinase) 2 V617F mutation in myeloproliferative neoplasms, and of other pseudokinase domain-activating mutations in JAK2, JAK1 and JAK3 in blood cancers, prompted great interest in understanding how pseudokinase domains regulate kinase domains in JAKs. Recent functional and mutagenesis studies identified residues required for the V617F ...
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