Involved in protein export. Acts as a chaperone by maintaining the newly synthesized protein in an open conformation. Functions as a peptidyl-prolyl cis-trans isomerase (By similarity). [protein]-peptidylproline (omega=180) = [protein]-peptidylproline (omega=0) About half TF is bound to the ribosome near the polypeptide exit tunnel while the other half is free in the cytoplasm. Consists of 3 domains; the N-terminus binds the ribosome, the middle domain has PPIase activity, while the C-terminus has intrinsic chaperone activity on its own. Belongs to the FKBP-type PPIase family. Tig subfamily.