Transcriptional activator activated by proteolytic cleavage through regulated intramembrane proteolysis (RIP). Involved in oxidative stress tolerance by mediating regulation of mitochondrial retrograde signaling during mitochondrial dysfunction. Interacts directly with the mitochondrial dysfunction DNA consensus motif 5'-CTTGNNNNNCA[AC]G-3', a cis-regulatory elements of several mitochondrial retrograde regulation-induced genes, and triggers increased oxidative stress tolerance. Interacts with RCD1. Localized primarily in endoplasmic reticulum membrane as dormant form and, upon oxidative stress, is processed into a transcriptionally active and nuclear form after a proteolytic cleavage through regulated intramembrane proteolysis (RIP). A number of isoforms are produced. According to EST sequences. Expressed in roots, rosette leaves, shoot apex, stems and flowers. By heat, salt stress, abscisic acid (ABA) and methyl methanesulfonate (MMS) treatment. The NAC domain includes a DNA binding domain and a dimerization domain.