Download MendeleyInhibition of K-RAS4B by a Unique Mechanism of Action: Stabilizing Membrane-Dependent Occlusion of the Effector-Binding Site.
Fang, Z., Marshall, C.B., Nishikawa, T., Gossert, A.D., Jansen, J.M., Jahnke, W., Ikura, M.(2018) Cell Chem Biol 25: 1327-1336.e4
- PubMed: 30122370
- DOI: https://doi.org/10.1016/j.chembiol.2018.07.009
- Primary Citation of Related Structures:
6CC9, 6CCH, 6CCX - PubMed Abstract:
KRAS is frequently mutated in several of the most lethal types of cancer; however, the KRAS protein has proven a challenging drug target. K-RAS4B must be localized to the plasma membrane by prenylation to activate oncogenic signaling, thus we endeavored to target the protein-membrane interface with small-molecule compounds. While all reported lead compounds have low affinity for KRAS in solution, the potency of Cmpd2 was strongly enhanced when prenylated K-RAS4B is associated with a lipid bilayer. We have elucidated a unique mechanism of action of Cmpd2, which simultaneously engages a shallow pocket on KRAS and associates with the lipid bilayer, thereby stabilizing KRAS in an orientation in which the membrane occludes its effector-binding site, reducing RAF binding and impairing activation of RAF. Furthermore, enrichment of Cmpd2 on the bilayer enhances potency by promoting interaction with KRAS. This insight reveals a novel approach to developing inhibitors of membrane-associated proteins.
Organizational Affiliation:
Department of Medical Biophysics, University of Toronto, Princess Margaret Cancer Centre, University Health Network, Toronto, ON M5G 2M9, Canada.
