FKBP12- tacrolimus komplekset bindes specifikt, kompetitivt hæmmende til calcineurin, hvilket medfører en calciumafhængig hæmning af T- cellernes signaltransduktion, således at transkriptionen af visse lymfokingener forhindres.
The FKBP12-tacrolimus complex specifically and competitively binds to and inhibits calcineurin, leading to a calcium-dependent inhibition of T-cell signal transduction pathways, thereby preventing transcription of a discrete set of lymphokine genes.