ATF4 binds composite CEBP-ATF elements located in three 33-bp tandem repeats in the promoter of the TRIB3 (TRB3, NIPK) gene (Ohoka et al. 2005, Ord and Ord 2005). ATF4 cooperates with DDIT3 to activate TRIB3 promoter activity (Ohoka et al. 2005). ATF4 also appears to bind as a heterodimer with CEBPB or CEBPG, which is required for full response to amino acid deficiency (inferred from mouse homologs).