A Novel Mode of Protein Kinase Inhibition Exploiting Hydrophobic Motifs of Autoinhibited Kinases
Protein kinase inhibitors with enhanced selectivity can be designed by optimizing binding interactions with less conserved inactive conformations because such inhibitors will be less likely to compete with ATP for binding and therefore may be less impacted by high intracellular concentrations of ATP. Analysis of the ATP-binding cleft in a number of inactive protein kinases, particularly in the autoinhibited conformation, led to the identification of a previously undisclosed non-polar region in this cleft. This ATP-incompatible hydrophobic region is distinct from the previously characterized hydrophobic allosteric back pocket, as well as the main pocket. Generalized hypothetical models of inactive kinases were constructed and, for the work described here, we selected the fibroblast growth factor receptor (FGFR) tyrosine kinase family as a case study. Initial optimization of a FGFR2 inhibitor identified from a library of commercial compounds was guided using structural information from the model. We describe the inhibitory characteristics of this compound in biophysical, biochemical, and cell-based assays, and have characterized the binding mode using x-ray crystallographic studies. The results demonstrate, as expected, that these inhibitors prevent activation of the autoinhibited conformation, retain full inhibitory potency in the presence of physiological concentrations of ATP, and have favorable inhibitory activity in cancer cells. Given the widespread regulation of kinases by autoinhibitory mechanisms, the approach described herein provides a new paradigm for the discovery of inhibitors by targeting inactive conformations of protein kinases.
- Research Organization:
- Brookhaven National Lab. (BNL), Upton, NY (United States)
- Sponsoring Organization:
- USDOE SC OFFICE OF SCIENCE (SC)
- DOE Contract Number:
- DE-AC02-98CH10886
- OSTI ID:
- 1041731
- Report Number(s):
- BNL-97409-2012-JA; JBCHA3; TRN: US201212%%143
- Journal Information:
- Journal of Biological Chemistry, Vol. 286, Issue 23; ISSN 0021-9258
- Country of Publication:
- United States
- Language:
- English
Similar Records
Structural Basis for Reduced FGFR2 Activity in LADD Syndrome: Implications for FGFR Autoinhibition and Activation
Structure of the Dictyostelium Myosin-II Heavy Chain Kinase A (MHCK-A) α-kinase domain apoenzyme reveals a novel autoinhibited conformation