Plays an important role in nitrogen catabolite repression. Down-regulates the expression of many genes involved in nitrogen utilization by inhibiting the GATA transcriptional activators GLN3 and GAT1. Under good nitrogen conditions, binds to the phosphorylated forms of GLN3 and GAT1 and sequesters them in the cytoplasm, preventing transcription of genes expressed upon nitrogen limitation. Is also an atypical glutaredoxin without a catalytical cysteine residue. Has glutathione peroxidase and thiol:disulfide oxidoreductase activities in both native and fibrillar form. Also shows insulin disulfide reductase and dehydroascorbic acid reductase (DHAR) activities. 2 glutathione + H2O2 = glutathione disulfide + 2 H2O kcat is 1.2 sec(-1) with bis-(2-hydroxyethyl) disulfide (HEDS) as substrate. Homodimer. Interacts with NNK1. The prion domain (PrD) is a Gln/Asn (Q/N)-rich domain, which is unstructured in its native, soluble form, and which forms a parallel in-register beta-sheet in its amyloid form. [URE3] is the prion form of URE2. [URE3] is the result of a conformational change of the cellular URE2 protein that becomes self-propagating and infectious. This conformational change generates a form of URE2 that assembles into amyloid fibrils. [URE3]-aggregates sequester soluble URE2, which then fails to retain GLN3 in the cytoplasm, resulting in GLN3 activation and consequently derepression of genes that are required for utilization of poor nirogen sources (PubMed:7909170). [URE3] can be cured by GdnHCl and by deletion of the molecular chaperone HSP104, which is required for [URE3] propagation (PubMed:11073991). Present with 7060 molecules/cell in log phase SD medium. Belongs to the GST superfamily. Mad yeast disease - Issue 47 of June 2004