RAF kinase

MAPKpathway

RAF Kinase

RAF kinase is a family of serine/threonine-specific protein kinases that play a crucial role in the mitogen-activated protein kinase (MAPK) signaling pathway. This pathway is involved in regulating cell proliferation, differentiation, and survival. The RAF kinase family consists of three members: A-Raf, B-Raf, and C-Raf (also known as Raf-1).

Structure

RAF kinases share a similar domain structure, including an N-terminal regulatory domain and a C-terminal kinase domain. The regulatory domain contains a Ras-binding domain (RBD) that interacts with activated Ras proteins, leading to the activation of RAF kinases. The kinase domain is responsible for phosphorylating downstream targets in the MAPK pathway.

Function

Upon activation by Ras, RAF kinases phosphorylate and activate MEK (MAPK/ERK kinase), which in turn phosphorylates and activates ERK (extracellular signal-regulated kinase). Activated ERK translocates to the nucleus and phosphorylates various transcription factors, leading to the expression of genes involved in cell proliferation and survival.

Clinical Significance

Mutations in RAF kinases have been implicated in various cancers, including melanoma and colorectal cancer. B-Raf mutations, in particular, are common in melanoma and have led to the development of targeted therapies such as vemurafenib and dabrafenib.

See also

• Mitogen-activated protein kinase
• MAPK/ERK pathway