Neuroblastoma RAS viral oncogene homolog-mutant, RAS-driven Rapidly Accelerated Fibrosarcoma signaling complexes (NRAS-mutant RAF complexes)

NRAS-mutant, RAS-driven RAF signaling complexes are multi-protein assemblies that play a pivotal role in the oncogenic signaling of various malignancies, most notably NRAS-mutant melanoma (Heidorn et al., 2010, Cell). In these cancers, mutations in the NRAS gene (commonly at codons 61, 12, or 13) result in a protein that is constitutively locked in an active, GTP-bound state (Dumaz et al., 2006, Cancer Res). This active NRAS recruits RAF kinases—specifically CRAF and BRAF—to the cell membrane, where they form homo- and heterodimers that are essential for activating the downstream MEK/ERK signaling cascade (Lavoie & Therrien, 2015, Nat Rev Mol Cell Biol). Unlike BRAF V600E mutations which signal as monomers, NRAS-driven signaling is strictly dependent on these dimeric RAF complexes, which renders them insensitive to first-generation RAF inhibitors like vemurafenib (Poulikakos et al., 2010, Nature). Consequently, drug development has shifted toward next-generation pan-RAF or Type II RAF inhibitors, such as belvarafenib and naporafenib, designed to block the kinase activity of these dimers without inducing paradoxical pathway activation (Yen et al., 2021, Nature). Targeting these complexes is a primary strategy for treating patients with NRAS-mutant tumors who currently have limited targeted therapy options (Jakob et al., 2012, Cancer).

Other names

NRAS-mutant RAF dimersNRAS-driven MAPK signaling complexNRAS-mutant CRAF-BRAF complexesRAS-RAF signaling complex

Inhibition of RAF kinase activity within the RAS-GTP driven dimer complex (CRAF-CRAF or BRAF-CRAF), preventing the phosphorylation of downstream MEK and ERK proteins.