MAPK3

Mitogen-Activated Protein Kinase 3 (MAPK3), commonly known as ERK1, is a serine/threonine kinase core to the MAPK/ERK signaling pathway. Activated via sequential phosphorylation by MEK1/2 (downstream of RAF kinases), it translocates to the nucleus to phosphorylate transcription factors like ELK1 and c-Fos, regulating cell proliferation, differentiation, and survival.
Dysregulated MAPK3 activity contributes to oncogenesis in melanoma, colorectal, and non-small cell lung cancer, driving uncontrolled growth. Clinically approved MEK inhibitors (e.g., trametinib) target its upstream regulators, though resistance (e.g., BRAF mutations) limits efficacy. Ongoing research explores combination therapies to enhance response and overcome resistance.