RARalpha (retinoic acid receptor alpha) is a 51 kD member of the nuclear hormone receptor family, NR1 subfamily. This nuclear protein contains modulating, DNA-binding, and steroid binding domains, and has been reported to have multiple isoforms. RARalpha is a nuclear receptor for retinoic acid that controls cell function by regulating gene expression and inducing profound effects on vertebrate development, acting as a morphogen and powerful teratogen. RARalpha is increased by protein kinase C stimulation, and estrogen; decreased at G0/G1 to S phase of cell cycle and in lymphocytes by cellular activation. RARalpha can be modified by phosphorylation and has been shown to interact with NCOA3 and NCOA6 co-activators leading to strong increases in the transcription of target genes. The Poly6168 antibody recognizes the N-terminal region of human RARalpha and has been shown to be useful for Western blotting.