Binds to an ERR-alpha response element (ERRE) containing a single consensus half-site, 5'-TNAAGGTCA-3'. Can bind to the medium-chain acyl coenzyme A dehydrogenase (MCAD) response element NRRE-1 and may act as an important regulator of MCAD promoter. May function as a modulator of the estrogen signaling pathway in the uterus. Induces the expression of PERM1 in the skeletal muscle (By similarity). Binds DNA as a monomer or a homodimer. Interacts (via the AF2 domain) with coactivator PPARGC1A (via the L3 motif); the interaction greatly enhances transcriptional activity of genes involved in energy metabolism. Interacts with PIAS4; the interaction enhances sumoylation. Interacts with MAPK15; promotes re-localization of ESRRA to the cytoplasm through a XPO1-dependent mechanism then inhibits ESRRA transcriptional activity. Co-localizes to the cytoplasm only in presence of MAPK15. Phosphorylation on Ser-19 enhances sumoylation on Lys-14 increasing repression of transcriptional activity. Sumoylated with SUMO2. Main site is Lys-14 which is enhanced by phosphorylation on Ser-19, cofactor activation, and by interaction with PIAS4. Sumoylation enhances repression of transcriptional activity, but has no effect on subcellular location nor on DNA binding (By similarity). Reversibly acetylated. Acetylation by PCAF/KAT2 at Lys-129, Lys-138, Lys-160 and Lys-162 and PCAF/KAT2 decreases transcriptional activity probably by inhibiting DNA-binding activity; deacetylation involves SIRT1 and HDAC8 and increases DNA-binding (By similarity). Belongs to the nuclear hormone receptor family. NR3 subfamily.