Synonyms:GRIM 12, GRIM12, KDRF, thioredoxin reductase 1, Thioredoxin reductase TR1, TR, TR1, TRXR1, TXNR, TXNRD1 Background:Isoform 1 may possess glutaredoxin activity as well as thioredoxin reductase activity and induces actin and tubulin polymerization, leading to formation of cell membrane protrusions. Isoform 4 enhances the transcriptional activity of estrogen receptors alpha and beta while isoform 5 enhances the transcriptional activity of the beta receptor only. Isoform 5 also mediates cell death induced by a combination of interferon-beta and retinoic acid.