Tyrosine Kinase 2-mediated Signal Transduction in T Lymphocytes Is Blocked by Pharmacological Stabilization of Its Pseudokinase Domain.Tokarski, J.S., Zupa-Fernandez, A., Tredup, J.A., Pike, K., Chang, C., Xie, D., Cheng, L., Pedicord, D., Muckelbauer, J., Johnson, S.R., Wu, S., Edavettal, S.C., Hong, Y., Witmer, M.R., Elkin, L.L., Blat, Y., Pitts, W.J., Weinstein, D.S., Burke, J.R.
(2015) J Biol Chem 290: 11061-11074
- PubMed: 25762719
- DOI: https://doi.org/10.1074/jbc.M114.619502
- Primary Citation of Related Structures:
- PubMed Abstract:
Inhibition of signal transduction downstream of the IL-23 receptor represents an intriguing approach to the treatment of autoimmunity. Using a chemogenomics approach marrying kinome-wide inhibitory profiles of a compound library with the cellular activity against an IL-23-stimulated transcriptional response in T lymphocytes, a class of inhibitors was identified that bind to and stabilize the pseudokinase domain of the Janus kinase tyrosine kinase 2 (Tyk2), resulting in blockade of receptor-mediated activation of the adjacent catalytic domain. These Tyk2 pseudokinase domain stabilizers were also shown to inhibit Tyk2-dependent signaling through the Type I interferon receptor but not Tyk2-independent signaling and transcriptional cellular assays, including stimulation through the receptors for IL-2 (JAK1- and JAK3-dependent) and thrombopoietin (JAK2-dependent), demonstrating the high functional selectivity of this approach. A crystal structure of the pseudokinase domain liganded with a representative example showed the compound bound to a site analogous to the ATP-binding site in catalytic kinases with features consistent with high ligand selectivity. The results support a model where the pseudokinase domain regulates activation of the catalytic domain by forming receptor-regulated inhibitory interactions. Tyk2 pseudokinase stabilizers, therefore, represent a novel approach to the design of potent and selective agents for the treatment of autoimmunity.
Leads Discovery and Optimization, and.