Biological actions of isoprenoids and cholesterol. This diagram of the cholesterol biosynthesis pathway shows the effects of inhibition of HMG-CoA reductase by statins. Decrease in isoprenylation of signaling molecules such as Ras, Rho, and Rac leads to modulation of various signaling pathways. BMP-2, bone morphogenetic protein-2; eNOS, endothelial nitric oxide synthase; t-PA, tissue-type plasminogen activator; ET-1, endothelin-1; PAI-1, plasminogen activator inhibitor-1.