Mitogen-activated protein kinase kinase 1 – Extracellular signal-regulated kinase pathway (MEK1-ERK pathway)

The MEK1-ERK pathway is a central component of the Mitogen-Activated Protein Kinase (MAPK) signaling cascade, which translates extracellular stimuli into cellular responses such as proliferation, differentiation, and survival (NIH, 2023). The cascade is typically initiated by the activation of small GTPases like Ras, which activates Raf kinases, leading to the sequential phosphorylation of MEK1/2 and subsequently ERK1/2 (UniProt, 2024). Once activated, ERK1/2 translocates to the nucleus to modulate the activity of various transcription factors that drive the cell cycle (PubMed, 2022). Aberrant activation of this pathway is a frequent driver in human cancers, often resulting from mutations in upstream regulators like BRAF or KRAS (StatPearls, 2023). Therapeutic intervention primarily focuses on MEK1/2 inhibitors, such as trametinib and cobimetinib, which are used to treat BRAF-mutant melanoma and other malignancies (PubChem, 2024). These drugs work by binding to the MEK protein, often in an allosteric pocket, to prevent the activation of ERK (NIH, 2023). While effective, targeting this pathway is often limited by the emergence of resistance mechanisms and significant toxicities, including skin rashes and ocular issues (StatPearls, 2023). Newer strategies include the development of ERK inhibitors to overcome resistance to upstream inhibition (PubMed, 2022). Overall, the MEK1-ERK axis remains one of the most validated and clinically significant targets in precision oncology (NIH, 2023).

Other names

MAPK/ERK pathwayRas-Raf-MEK-ERK pathwayMEK-ERK signaling cascadeERK signaling pathwayp42/44 MAPK pathway

Inhibition of the kinase activity of MEK1/2 or ERK1/2, which prevents the phosphorylation of downstream substrates in the MAPK cascade, leading to the suppression of pro-proliferative gene expression and induction of cell cycle arrest.