Ncoa5 encodes a coregulator for the alpha and beta estrogen receptors and the orphan nuclear receptor NR1D2. The nuclear receptor coactivator 5 localizes to the nucleus, and is thought to have both coactivator and corepressor functions. Its interaction with nuclear receptors is independent of the AF2 domain on the receptors, which is known to regulate interaction with other coreceptors. Two alternatively spliced transcript variants for this gene have been described. However, the full length nature of one of the variants has not been determined.