The function of FKBP3 (FKBP prolyl isomerase 3, Ensembl gene identifier ENSG00000100442) is as follows. FK506- and rapamycin-binding proteins (FKBPs) constitute a family of receptors for the two immunosuppressants which inhibit T-cell proliferation by arresting two distinct cytoplasmic signal transmission pathways. PPIases accelerate the folding of proteins.