Modulation of activation-loop phosphorylation by JAK inhibitors is binding mode dependent Journal Article


Authors: Andraos, R.; Qian, Z.; Bonenfant, D.; Rubert, J.; Vangrevelinghe, E.; Scheufler, C.; Marque, F.; Régnier, C. H.; De Pover, A.; Ryckelynck, H.; Bhagwat, N.; Koppikar, P.; Goel, A.; Wyder, L.; Tavares, G.; Baffert, F.; Pissot-Soldermann, C.; Manley, P. W.; Gaul, C.; Voshol, H.; Levine, R. L.; Sellers, W. R.; Hofmann, F.; Radimerski, T.
Article Title: Modulation of activation-loop phosphorylation by JAK inhibitors is binding mode dependent
Abstract: Janus kinase (JAK) inhibitors are being developed for the treatment of rheumatoid arthritis, psoriasis, myeloproliferative neoplasms, and leukemias. Most of these drugs target the ATP-binding pocket and stabilize the active conformation of the JAK kinases. This type I binding mode can lead to an increase in JAK activation loop phosphorylation, despite blockade of kinase function. Here we report that stabilizing the inactive state via type II inhibition acts in the opposite manner, leading to a loss of activation loop phosphorylation. We used X-ray crystallography to corroborate the binding mode and report for the first time the crystal structure of the JAK2 kinase domain in an inactive conformation. Importantly, JAK inhibitor-induced activation loop phosphorylation requires receptor interaction, as well as intact kinase and pseudokinase domains. Hence, depending on the respective conformation stabilized by a JAK inhibitor, hyperphosphorylation of the activation loop may or may not be elicited. SIGNIFICANCE: This study shows that JAK inhibitors can lead to an increase of activation loop phosphorylation in a manner that is binding mode dependent. Our results highlight the need for detailed understanding of inhibitor mechanism of action, and that it may be possible to devise strategies that avoid target priming using alternative modes of inhibiting JAK kinase activity for the treatment of JAKdependent diseases. © 2012 American Association for Cancer Research.
Journal Title: Cancer Discovery
Volume: 2
Issue: 6
ISSN: 2159-8274
Publisher: American Association for Cancer Research  
Date Published: 2012-06-01
Start Page: 512
End Page: 523
Language: English
DOI: 10.1158/2159-8290.cd-11-0324
PROVIDER: scopus
PMCID: PMC5022112
PUBMED: 22684457
DOI/URL:
Notes: --- - "Cited By (since 1996): 1" - "Export Date: 1 October 2012" - "Source: Scopus"
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  1. Ross Levine
    775 Levine
  2. Neha Bhagwat
    22 Bhagwat
  3. Aviva J Goel
    7 Goel