Rapidly accelerated fibrosarcoma kinase (RAF kinase) (RAF)

RAF kinases (ARAF, BRAF, and CRAF) are serine/threonine-specific protein kinases that function as key mediators in the mitogen-activated protein kinase (MAPK) signaling cascade (Source: UniProt). They are typically activated by RAS GTPases at the plasma membrane, leading to a phosphorylation relay that ultimately regulates gene expression involved in cell proliferation, survival, and differentiation (Source: PubMed). Mutations in these kinases, particularly the BRAF V600E variant, lead to constitutive pathway activation and are major drivers in cancers such as melanoma, colorectal, and non-small cell lung cancer (Source: NIH). XP-102 is a clinical-stage, potent pan-RAF inhibitor that targets both the monomeric and dimeric forms of RAF kinases (Source: Xcovery). Unlike first-generation Type I inhibitors, XP-102 is a Type II inhibitor designed to avoid paradoxical activation of the MAPK pathway in cells with wild-type BRAF and upstream RAS mutations, potentially offering a wider therapeutic window and overcoming common resistance mechanisms (Source: ClinicalTrials.gov).

Other names

ARAFBRAFCRAFRaf-1v-Raf murine sarcoma viral oncogene homologSerine/threonine-protein kinase Raf

XP-102 is a Type II pan-RAF inhibitor that binds to the inactive (DFG-out) conformation of ARAF, BRAF, and CRAF kinases. This binding prevents both the catalytic activity of the kinases and the formation of active RAF dimers, thereby inhibiting the downstream phosphorylation of MEK and ERK in the MAPK signaling pathway (Source: PubMed, Xcovery).