Rapidly Accelerated Fibrosarcoma kinases (RAF)

The Rapidly Accelerated Fibrosarcoma (RAF) kinase family consists of three highly conserved serine/threonine kinases: A-RAF, B-RAF, and C-RAF (Raf-1). These enzymes function as essential components of the mitogen-activated protein kinase (MAPK) signaling cascade, specifically acting as MAP kinase kinase kinases (MAP3Ks) that activate MEK1/2 (Source: UniProt P15056, P04041). Under physiological conditions, RAF kinases are recruited and activated by RAS-GTP at the plasma membrane, facilitating signals that govern cell growth, differentiation, and survival. Dysregulation of this pathway, most commonly through gain-of-function mutations in BRAF (such as the V600E substitution), is a primary driver in numerous malignancies, including cutaneous melanoma, colorectal cancer, and papillary thyroid carcinoma (Source: NIH National Cancer Institute). Therapeutic strategies targeting RAF kinases involve small-molecule inhibitors designed to shut down hyperactive signaling. While effective, these treatments often face challenges such as the development of secondary malignancies due to paradoxical pathway activation in BRAF wild-type cells and the emergence of complex resistance mechanisms involving upstream or downstream pathway alterations (Source: StatPearls NBK499845).

Other names

RAF familyMAP kinase kinase kinaseA-RAFB-RAFC-RAFRaf-1Serine/threonine-protein kinase Raf

RAF inhibitors primarily function as ATP-competitive inhibitors that bind to the kinase domain of RAF proteins, preventing the phosphorylation and activation of downstream MEK1 and MEK2, thereby halting the MAPK/ERK signaling cascade (Source: PubMed PMC4109288).