Mitogen-activated protein kinases (MAPKs) are a large family of proteins that regulate diverse cellular functions in eukaryotes, including gene expression, proliferation, differentiation and apoptosis (1). MAPK signaling pathways typically include three sequentially activated kinases, and these pathways are triggered in response to extracellular stimuli, such as cytokines, mitogens, growth factors and oxidative stress (1). Ultimately, the signal is transmitted to the nucleus, with the activation of a specific transcription factor that modulates the expression of one or more genes.
Among MAPK pathways, the RAS-RAF-MEK-ERK signaling pathway has been studied extensively. Mutations in RAS family proteins and resultant dysregulation of the signaling pathway are implicated in a variety of cancers. Therefore, this pathway is a popular target for anticancer drug development.
