Only after it has been modified by a special enzyme with the jaw-breaking name farnesyl transferase does Ras protein become able to function as a relay switch. Drugs that inhibit farnesyl transferase offer great promise as anticancer therapies. In tests on animals, farnesyl transferase inhibitors induce the regression of tumors and prevent the formation of new ones. Amplifying the signal. The third step in the decision process is the amplification of the signal within the cytoplasm.
Cells use an ingenious trick to amplify the signal.
It activates other protein kinases that in their turn activate still others. And each and every one it activates behaves the same way too, activating still more, in a cascade of ever-widening effect. At each stage of the relay, the signal is amplified thousands-fold. Mutations in any of the protein kinases can dangerously increase the already amplified signal and lead to cancer. Therapies directed at this stage of the decision process initially employed protein kinase inhibitors.