FK506 Binding Protein 12 (FKBP12) is a small, ubiquitous protein that belongs to the immunophilin family. This family is known for its role in immunosuppression and protein folding. The protein is about 12 kDa in size, hence the "12" in its name. It is primarily known for its ability to bind to the immunosuppressive drugs FK506 (tacrolimus) and rapamycin, which are used in organ transplantation to prevent rejection.
