Question

The Ras-Raf-MAPK pathway directly controls the activity of ——-??

TCF.

Myc.

Akt.

Fos.

Answer 1

Option 4 is the correct answer.

The Ras-Raf-MAPK pathway directly controls the activity of Fos. MAPK regulates the activities of several transcription factors. MAPK can phosphorylate C-myc. MAPK phosphorylates and activates MNK, which, in turn, phosphorylates CREB. MAPK also regulates the transcription of the C-Fos gene. Three distinct MAPKs contribute to induction of AP-1 activity. It is a sequence-specific transcriptional activator composed of members of the Jun and Fos families. Phosphorylation of TCF/Elk-1 bound to the c-fos promoter by the ERKs stimulates its transcriptional activity, thus leading to c-fos induction. This is how, the Ras-Raf-MAPK pathway directly controls the activity of Fos. By altering the levels and activities of transcription factors, MAPK leads to altered transcription of genes that are important for the cell cycle.