Transcriptional activator that binds to regulatory elements in promoter regions in a cell- and response element (target)-specific manner (PubMed:7811288). Induces gene expression by binding as monomers to the NR4A1 response element (NBRE) 5'-AAAAGGTCA-3' site and as homodimers to the Nur response element (NurRE) site in the promoter of their regulated target genes (PubMed:10523643). Plays a role in the regulation of proliferation, survival and differentiation of many different cell types and also in metabolism and inflammation. Mediates proliferation of vascular smooth muscle, myeloid progenitor cell and type B pancreatic cells; promotes mitogen-induced vascular smooth muscle cell proliferation through transactivation of SKP2 promoter by binding a NBRE site (By similarity). Upon PDGF stimulation, stimulates vascular smooth muscle cell proliferation by regulating CCND1 and CCND2 expression (PubMed:16945922). In islets, induces type B pancreatic cell proliferation through up-regulation of genes that activate cell cycle, as well as genes that cause degradation of the CDKN1A (PubMed:24706823). Negatively regulates myeloid progenitor cell proliferation by repressing RUNX1 in a NBRE site-independent manner. During inner ear, plays a role as a key mediator of the proliferative growth phase of semicircular canal development (By similarity). Mediates also survival of neuron and smooth muscle cells; mediates CREB-induced neuronal survival, and during hippocampus development, plays a critical role in pyramidal cell survival and axonal guidance. Is required for S phase entry of the cell cycle and survival of smooth muscle cells by inducing CCND1, resulting in RB1 phosphorylation. Binds to NBRE motif in CCND1 promoter, resulting in the activation of the promoter and CCND1 transcription (By similarity). Also plays a role in inflammation; Upon TNF stimulation, mediates monocyte adhesion by inducing the expression of VCAM1 and ICAM1 by binding to the NBRE consensus site (By similarity). In mast cells activated by Fc-epsilon receptor cross-linking, promotes the synthesis and release of cytokines but impairs events leading to degranulation. Also plays a role in metabolism; by modulating feeding behavior; and by playing a role in energy balance by inhibiting the glucocorticoid-induced orexigenic neuropeptides AGRP expression, at least in part by forming a complex with activated NR3C1 on the AGRP-glucocorticoid response element (GRE), and thus weakening the DNA binding activity of NR3C1. Upon catecholamines stimulation, regulates gene expression that controls oxidative metabolism in skeletal muscle (By similarity). Plays a role in glucose transport by regulating translocation of the SLC2A4 glucose transporter to the cell surface (By similarity). Finally, during gastrulation plays a crucial role in the formation of anterior mesoderm by controlling cell migration (By similarity). Also participates in cardiac hypertrophy by activating PARP1 (PubMed:25625556). Interacts with SIX3 (via homeobox); differentially regulates the transcriptional activities of NR4A3. Interacts with NR3C1 (via nuclear receptor DNA-binding domain); the interactions represses transcription activity of NR4A3 on the POMC promoter Nur response element (NurRE) (PubMed:15591535). Interacts with TRIM28; the interactions potentiates NR4A3 activity on NurRE promoter (PubMed:19321449). Binds DNA as a monomer and homodimer (PubMed:10523643). Interacts with PARP1; activates PARP1 by improving acetylation of PARP1 and suppressing the interaction between PARP1 and SIRT1 (PubMed:25625556). Interacts with the constituents of DNA-PK heterotrimer PRKDC, XRCC6 and XRCC5; phosphorylates and prevents NR4A3 ubiquitinylation and degradation (By similarity). Interacts with NCOA2; potentiates the activity of the NR4A3. Interacts with NCOA1, NCOA3, MED1 and KAT2B. Interacts with EP300 and NCOA2; mediates the recruitment of MED1 in the coactivator complex (By similarity). Expressed at high levels in cultured apoptotic neuronal cells and fetal brain, and at low level in adult brain. By PDGF through a CREB-dependent transactivation of the NOR1 promoter. The AF-1 domain mediates transcription activation. The N-terminal region (1-292) directly interacts with the C-terminal LBD (380-627): the interaction is potentiated by AF-1-mediated recruitment of NCOA2. Phosphorylated by PRKDC. Belongs to the nuclear hormone receptor family. NR4 subfamily.