The protein encoded by this gene 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 is thought to function as an ER chaperone and may also act as a component of membrane cytoskeletal scaffolds. Multiple alternatively spliced variants, encoding the same protein, have been identified. [provided by RefSeq, Sep 2008].