An engineered protein antagonist of K-Ras/B-Raf interaction.Kauke, M.J., Traxlmayr, M.W., Parker, J.A., Kiefer, J.D., Knihtila, R., McGee, J., Verdine, G., Mattos, C., Wittrup, K.D.
(2017) Sci Rep 7: 5831-5831
- PubMed: 28724936
- DOI: 10.1038/s41598-017-05889-7
- Primary Citation of Related Structures:
- PubMed Abstract:
Ras is at the hub of signal transduction pathways controlling cell proliferation and survival. Its mutants, present in about 30% of human cancers, are major drivers of oncogenesis and render tumors unresponsive to standard therapies. Here we report t ...
Ras is at the hub of signal transduction pathways controlling cell proliferation and survival. Its mutants, present in about 30% of human cancers, are major drivers of oncogenesis and render tumors unresponsive to standard therapies. Here we report the engineering of a protein scaffold for preferential binding to K-Ras G12D. This is the first reported inhibitor to achieve nanomolar affinity while exhibiting specificity for mutant over wild type (WT) K-Ras. Crystal structures of the protein R11.1.6 in complex with K-Ras WT and K-Ras G12D offer insight into the structural basis for specificity, highlighting differences in the switch I conformation as the major defining element in the higher affinity interaction. R11.1.6 directly blocks interaction with Raf and reduces signaling through the Raf/MEK/ERK pathway. Our results support greater consideration of the state of switch I and provide a novel tool to study Ras biology. Most importantly, this work makes an unprecedented contribution to Ras research in inhibitor development strategy by revealing details of a targetable binding surface. Unlike the polar interfaces found for Ras/effector interactions, the K-Ras/R11.1.6 complex reveals an extensive hydrophobic interface that can serve as a template to advance the development of high affinity, non-covalent inhibitors of K-Ras oncogenic mutants.
Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA.