FK506 Binding Protein 3 (FKBP3)

FK506-binding protein 3 is a member of the immunophilin protein family, which play a role in immunoregulation and basic cellular processes involving protein folding and trafficking. This encoded protein is a cis-trans prolyl isomerase that binds the immunosuppressants FK506 and rapamycin. It has a higher affinity for rapamycin than for FK506 and thus may be an important target molecule for immunosuppression by rapamycin.

Hung and Schreiber (1992) isolated a cDNA for FKBP25 from a human hippocampal cDNA library by oligonucleotide screening. The nucleotide sequence revealed an open reading frame that encodes a 224-amino acid polypeptide. Human FKBP25 shows 97% amino acid identity with bovine protein and 62% homology with human FKBP12.