Transcriptional regulator of the circadian clock components: CLOCK, ARNTL/BMAL1, ARNTL2/BMAL2, PER1/3, CRY1/2, NR1D1/2 and RORA/C. Positively regulates the transcriptional activity of CLOCK a core component of the circadian clock. Regulates transcription through chromatin remodeling by interacting with other proteins in chromatin as well as proteins in the basic transcriptional machinery. May be important for embryonic and postnatal development. May be involved in neuronal differentiation. In neurons, localized to neurites. Expressed in all tissues examined with higher expression in the heart and brain. No expression was seen in the corpus callosum of the brain. The poly-Gln tract is polymorphic and the number of Gln varies from 12 to 14 (PubMed:11404004). The size of the poly-Gln region may influence the age at onset of spinocerebellar ataxia type 2 (SCA2) (PubMed:10915763). The disease is caused by variants affecting the gene represented in this entry. Extended N-terminus.