ATF4 and CEBPB or CEBPG bind a CEBP-ATF regulatory element (CARE) in the promoter of the ASNS gene (Siu et al 2001, Chen et al. 2004, inferred from mouse homologs). ATF4 binds rapidly during the first 2 hours after amino acid deprivation (Chen et al. 2004). ATF3 and CEBPB accumulate on the ASNS promoter more slowly and appear to correlate with decreasing transcription of ASNS (Chen et al. 2004). EIF2AK1 acts via ATF4 to activate transcription of ASNS in response to heme deficiency (inferred from mouse homologs).