RAF kinases, central to the MAPK pathway, are highly implicated in metastatic melanomas and represent an established drug target. However, the current pharmacological intervention with RAF inhibitors exhibits adverse effects including intrinsic drug resistance and the development of secondary malignancies. RAF kinases have kinase domain and regulatory domains that are jointly involved in regulation, substrate recognition and catalysis. We will apply biochemistry, structural biology, and biophysics to delineate the regulatory mechanisms of the full-length RAF kinases in different genetic backgrounds.
The Specific Aims of the proposal are to (1) Discover how regulatory domains coordinate to activate wild type BRAF. (2) Elucidate how the ?loss- of-function? BRAF mutants (impaired or ?kinase-dead?) gain enhanced ability to drive tumors in concert with CRAF. We will characterize the full-length BRAFkinase-dead/CRAF to understand how ?kinase-dead? mutations affect kinase function. (3) Illuminate how ?gain-of-function? P-loop mutation aberrantly activates BRAF. Our goal is to understand the regulation mechanisms of RAF enzymes to facilitate discovery of effective and specific inhibitors to block the disease-associated RAF kinases.
The discovery of BRAF as a major driver of melanoma led to a substantial clinical success of current BRAF therapies, however, drug resistance and side effects have limited their application. Our studies will address the molecular mechanisms of these adverse effects and identify novel drug targets to provide a rationale for the next generation of anti-BRAF therapies with improved efficacy and potency. Our findings would have an impact on the treatment of BRAF-driven melanoma.
