Enables protein folding chaperone. Involved in protein maturation by protein folding. Located in rough endoplasmic reticulum. Expressed in neurons. Used to study neurodegenerative disease. Human ortholog(s) of this gene implicated in several diseases, including Alzheimer's disease; artery disease (multiple); autoimmune disease (multiple); and eye disease (multiple). Is an ortholog of human PON1 (paraoxonase 1); PON2 (paraoxonase 2); and PON3 (paraoxonase 3).