The protein encoded by this gene is a member of the Par bZIP transcription factor family and binds to specific sequences in the promoters of several genes, such as albumin, Cyp2a4, and Cyp2a5. The encoded protein can bind DNA as a homo- or heterodimer and is involved in the regulation of some circadian rhythym genes. Three transcript variants encoding different isoforms have been found for this gene. [provided by RefSeq, Feb 2014]