PMID: 25195011

Authors:

Chaikuad A, M C Tacconi E, Zimmer J, Liang Y, Gray NS, Tarsounas M, Knapp S

Title:

A unique inhibitor binding site in ERK1/2 is associated with slow binding kinetics.

Journal:

Nat Chem Biol. 2014 Oct;10(10):853-60. doi: 10.1038/nchembio.1629. Epub 2014 Sep , 7.

Abstract:

Activation of the ERK pathway is a hallmark of cancer, and targeting of upstream signaling partners led to the development of approved drugs. Recently, SCH772984 has been shown to be a selective and potent ERK1/2 inhibitor. Here we report the structural mechanism for its remarkable selectivity. In ERK1/2, SCH772984 induces a so-far-unknown binding pocket that accommodates the piperazine-phenyl-pyrimidine decoration. This new binding pocket was created by an inactive conformation of the phosphate-binding loop and an outward tilt of helix alphaC. In contrast, structure determination of SCH772984 with the off-target haspin and JNK1 revealed two canonical but distinct type I binding modes. Notably, the new binding mode with ERK1/2 was associated with slow binding kinetics in vitro as well as in cell-based assay systems. The described binding mode of SCH772984 with ERK1/2 enables the design of a new type of specific kinase inhibitors with prolonged on-target activity.