From our position in the cell's cytoplasm, we can see the ends of the receptor (in gray) being drawn together as the growth factor outside the cell binds. The receptor ends activate each other before binding an adaptor molecule (shown in pink) and an exchange factor (shown in light purple). An important protein in this pathway, known as Ras (shown in red) then swings around to be activated. Ras, in turn, activates three white "Raf" proteins, before another protein (shown in blue) moves in to deactivate it. Ras is a key "switch" in this pathway – mutations in the ras gene and protein are common in cancer cells.