PMID: 25684575

Authors:

Fetics SK, Guterres H, Kearney BM, Buhrman G, Ma B, Nussinov R, Mattos C

Title:

Allosteric Effects of the Oncogenic RasQ61L Mutant on Raf-RBD.

Journal:

Structure. 2015 Mar 3;23(3):505-16. doi: 10.1016/j.str.2014.12.017. Epub 2015 Feb, 12.

Abstract:

The Ras/Raf/MEK/ERK signal transduction pathway is a major regulator of cell proliferation activated by Ras-guanosine triphosphate (GTP). The oncogenic mutant RasQ61L is not able to hydrolyze GTP in the presence of Raf and thus is a constitutive activator of this mitogenic pathway. The Ras/Raf interaction is essential for the activation of the Raf kinase domain through a currently unknown mechanism. We present the crystal structures of the Ras-GppNHp/Raf-RBD and RasQ61L-GppNHp/Raf-RBD complexes, which, in combination with MD simulations, reveal differences in allosteric interactions leading from the Ras/Raf interface to the Ras calcium-binding site and to the remote Raf-RBD loop L4. In the presence of Raf, the RasQ61L mutant has a rigid switch II relative to the wild-type and increased flexibility at the interface with switch I, which propagates across Raf-RBD. We show that in addition to local perturbations on Ras, RasQ61L has substantial long-range effects on the Ras allosteric lobe and on Raf-RBD.