Rapidly accelerated fibrosarcoma (Raf) kinase is a serine/ threonine kinase and component of the MAPK/ERK signaling pathway. Upon activation by upstream RAS signaling, Raf dimerizes and phosphorylates MEK1 leading to activation of transcription factors forcell growth, proliferation and survival. Raf exists as three isoforms, A-RAF, B-RAF and C-RAF, that all consist of three conserved regions with domain specific functions. CR1 contains a cysteine-rich domain and a RASbinding domain, CR2 is essential for negative regulation through inhibition of phosphorylation sites, and CR3 is the kinase domain. B-RAF is the most prominent isoform, expressed in most tissues, and localized to the cytosol. Activating mutations in B-RAF have been found in various cancers, including melanoma and non-small cell lung cancer as well as in patients with Langerhans cell histiocytosis. Note: Erythrocytes staining may be observed in some tissues.
Rapidly accelerated fibrosarcoma (Raf) kinase is a serine/ threonine kinase and component of the MAPK/ERK signaling pathway. Upon activation by upstream RAS signaling, Raf dimerizes and phosphorylates MEK1 leading to activation of transcription factors forcell growth, proliferation and survival. Raf exists as three isoforms, A-RAF, B-RAF and C-RAF, that all consist of three conserved regions with domain specific functions. CR1 contains a cysteine-rich domain and a RASbinding domain, CR2 is essential for negative regulation through inhibition of phosphorylation sites, and CR3 is the kinase domain. B-RAF is the most prominent isoform, expressed in most tissues, and localized to the cytosol. Activating mutations in B-RAF have been found in various cancers, including melanoma and non-small cell lung cancer as well as in patients with Langerhans cell histiocytosis. Note: Erythrocytes staining may be observed in some tissues.