The mammalian mevalonate pathway. The scheme shows the key signaling molecules and enzymes of the mevalonate pathway. Statins inhibit HMG-CoA reductase, FTI-277 inhibits farnesyl transferase (FTase), GGTI-298 inhibits geranylgeranyl transferase (GGTase). Farnesol (F-OH) is the cell-permeable prodrug of farnesyl pyrophosphate (F-PP) and geranylgeranol (GG-OH) is the cell permeable prodrug of geranylgeranyl pyrophosphate (GG-PP).