A macrocyclic triene antibiotic that binds to and inhibits the molecular target of rapamycin (mTOR) in complex with FKBP12. mTor acts as a negative regulator of autophagy hence inhibiton with rapamycin leads to activation of autophagy. Rapamycin is a potent immunosuppressant and has anticancer and antifungal activity. In addition it inhibits interleukin-2-induced phosphorylation and activation of p70 S6 kinase.