This ERK pathway is implicated in Huntington's disease. The ligands BDNF, EGF, and Glu bind to their respective receptors (TrkB, EGFR, mGluR) and start a signal transduction pathway starting with RAS and RAF1, which leads to the stimulation of MEK then ERK. ERK promotes function of MSK1 (a downstream kinase), ElK1 and CREB (transcription factors), and caspases 3/7 (apoptotic molecules). These downstream targets are implicated in producing the effects of Huntington's disease at the cellular level. This pathway is based on Figure 1 from Bodai et al.
Proteins on this pathway have targeted assays available via the [CPTAC Assay Portal](https://assays.cancer.gov/available_assays?wp_id=WP3853)