Figure 2.

The circRNA/MAPK signaling axis in CRC. This signaling pathway is initiated by the binding of activated growth factors, such as epidermal growth factor (EGF), to tyrosine kinase receptors on the cell surface. This causes the downstream RAS to increase the GTP binding state. RAS-GTP dimers recruit RAF or RAF/MEK dimers to the plasma membrane and promote the activation of RAF and the formation of MEK homologous dimers. This is followed by activation and phosphorylation of downstream ERKs. Finally, ERKs induce phosphorylation of transcription factors and other substrates to participate in cell proliferation, differentiation, migration, and apoptosis in the nucleus.