Transcriptional activator that recognizes and binds to the DNA sequence 5'-[AG]TAAA[TC]A-3' and regulates different processes, such as apoptosis and autophagy. Acts as a positive regulator of autophagy in skeletal muscle: in starved cells, enters the nucleus following dephosphorylation and binds the promoters of autophagy genes, thereby activating their expression, resulting in proteolysis of skeletal muscle proteins (By similarity). Triggers apoptosis in the absence of survival factors, including neuronal cell death upon oxidative stress (By similarity). In response to metabolic stress, translocates into the mitochondria where it promotes mtDNA transcription. Also acts as a key regulator of chondrogenic commitment of skeletal progenitor cells in response to lipid availability: when lipids levels are low, translocates to the nucleus and promotes expression of sox9, which induces chondrogenic commitment and suppresses fatty acid oxidation (By similarity). Also acts as a key regulator of regulatory T-cells (Treg) differentiation (By similarity). Retention in the cytoplasm contributes to its inactivation (By similarity). Translocates to the nucleus upon oxidative stress and in the absence of survival factors (By similarity). Localized to the animal hemisphere during early cleavage stages. At the late neurula, localized in the anterior neural plate, neural crest cells and in the hatching gland (PubMed:15567714). As development progresses, expression becomes less localized, being observed in a variety of organs and tissues including the head, branchial arches and somites by stage 32 (PubMed:15567714). Expressed both maternally and zygotically. Maternal expression decreases during early cleavage stages becoming absent during gastrulation (PubMed:15567714). Zygotic expression begins during neurulation and expression levels decrease rapidly through the early tadpole stages before becoming enhanced again up till stage 39 (PubMed:15567714). Dephosphorylation may promote translocation to the nucleus where the protein induces transcription of target genes and triggers apoptosis.