Recognizes the core sequence 5'-TAAACA-3'. Binds to NFAT-like motifs (purine-rich) in the IL2 promoter. Also binds to HIV-1 long terminal repeat. May be involved in both positive and negative regulation of important viral and cellular promoter elements. 3 isoforms of the human protein are produced by alternative splicing. Note: This description may include information from UniProtKB.