Grant: Project Grant

Our lab has a long-standing interest in the RAS-ERK pathway, a critical signaling cascade involving four key proteins: RAS, RAF, MEK, and ERK, which are essential for cell proliferation. Notably, dysregulation of this pathway is implicated in up to 50% of human cancers. Over the past two decades, enormous efforts have been dedicated to developing selective inhibitors to block its activity in tumor cells. This work has yielded several new targeted drugs, but their therapeutic index is often limited, and numerous bypass mechanisms can lead to resistance. A major focus of our lab is on the regulation of RAF. In normal cells, RAF relays signals between RAS and MEK in a coordinated manner. The mechanism underlying this process is yet not fully understood. RAF is also a major oncogene that is frequently mutated in human cancer cells, resulting in the production of a permanently active protein that drives unrestrained cell proliferation. Using molecular, biochemical, structural, and biophysical approaches, our recent work has shed light on the impact of oncogenic mutations on the conformation of RAF, leading to its constitutive activation. Our findings provide a solid framework for elucidating the sequence of events that governs RAF's conformational transition from an inactive to an active protein. In this application, we aim to build on these findings by characterizing new structural aspects of both wild-type and oncogenic RAF to gain a comprehensive understanding of the activation process. In addition, given the conservation of the RAS-ERK pathway through evolution, we will investigate how a novel multi-protein complex assembled by scaffold proteins regulates RAF activity in the fruit fly Drosophila. We envision that a detailed understanding of RAF regulation at both the functional and structural levels will pave the way for the development of radically novel and effective inhibitors targeting RAS-ERK dependent malignancies, with reduced resistance and toxicity.