FKBP52: Lysates

FK506 binding protein, also called FKBP52 and FKBP4, is a peptidyl-prolyl isomerase that catalyzes the transition between cis- and trans- proline residues critical for proper folding of proteins. It associates with HSP90 complexes that are critical for the proper folding of steroid receptors. FKBP52 knockout mice have abnormal reproductive organ development due to disruption of androgen receptor folding. Phosphorylation of FKBP52 at Thr143 is believed to be important for steroid receptor activity.