All of the following statements about immunosuppressants are true EXCEPT :

Mycophenolate mofetil acts by blocking IMP dehydrogenase. Cyclosporine and tacrolimus are calcineurin inhibitors that act by decreasing the transcription of IL-2 gene. Cyclo­sporine is commonly used to prevent rejection in transplant recipients. Sirolimus acts by inhibiting mTOR (a tyrosine kinase) that is the target of IL-2.