Acts as an intracellular estrogen-binding protein. May be involved in modulating cellular levels and biological functions of estrogens in the pancreas. May act as a chaperone that inhibits aggregation of misfolded proteins. {ECO:0000269|PubMed:19150607, ECO:0000269|PubMed:19429457}. This is the function of ENSG00000185615 (PDIA2, protein disulfide isomerase family A member 2).