Crystal Structure of a Conformation-Selective Casein Kinase-1 InhibitorMashhoon, N., Demaggio, A.J., Tereshko, V., Bergmeier, S.C., Egli, M., Hoekstra, M.F., Kuret, J.
(2000) J Biol Chem 275: 20052-20060
- PubMed: 10749871
- DOI: https://doi.org/10.1074/jbc.M001713200
- Primary Citation of Related Structures:
- PubMed Abstract:
Members of the casein kinase-1 family of protein kinases play an essential role in cell regulation and disease pathogenesis. Unlike most protein kinases, they appear to function as constitutively active enzymes. As a result, selective pharmacological inhibitors can play an important role in dissection of casein kinase-1-dependent processes. To address this need, new small molecule inhibitors of casein kinase-1 acting through ATP-competitive and ATP-noncompetitive mechanisms were isolated on the basis of in vitro screening. Here we report the crystal structure of 3-[(2,4,6-trimethoxyphenyl) methylidenyl]-indolin-2-one (IC261), an ATP-competitive inhibitor with differential activity among casein kinase-1 isoforms, in complex with the catalytic domain of fission yeast casein kinase-1 refined to a crystallographic R-factor of 22.4% at 2.8 A resolution. The structure reveals that IC261 stabilizes casein kinase-1 in a conformation midway between nucleotide substrate liganded and nonliganded conformations. We propose that adoption of this conformation by casein kinase-1 family members stabilizes a delocalized network of side chain interactions and results in a decreased dissociation rate of inhibitor.
Center for Biotechnology, Ohio State University College of Medicine, Columbus, Ohio 43210, ICOS Corporation, Bothell, Washington 98021, USA.