FKBP1B and Infertility: Our data demonstrated that FKBP12.6 deficiency significantly inhibited infertility induced by 14 days FK506 treatment, and remarkably reversed FK506-induced the increased expressions of DSCR1.1 and the declined expression of PPP3CC and PPP3R2 in immature sperm even for a very short time of FK506 administration, indicating that FKBP12.6 mediated the FK506-induced damage to the entire sperm maturation process in mice.