Binds a variety of cellular and viral promoters including fibrinogen, alpha-globin, SV40 and HIV-1 promoters. Activation of the alpha-globin promoter in erythroid cells is via synergistic interaction with UBP1 (By similarity). Functions as part of the SSP (stage selector protein) complex. Facilitates the interaction of the gamma-globin genes with enhancer elements contained in the locus control region in fetal erythroid cells. Interacts by binding to the stage selector element (SSE) in the proximal gamma-globin promoter. Binds to DNA as a dimer, isoform 3 does not bind to DNA or affect the binding of isoform 1 to DNA. Interacts with UBP1 and PIAS1, and is probably part of a complex containing TFCP2, UBP1 and PIAS1 (By similarity). Component of the SSP (stage selector protein) complex, which appears to be a heteromer of TFCP2 and 2 copies of NFE4. Ubiquitous. Expressed in brain, ovary, kidney, thymus, spleen, liver, adrenal, heart and lung (at protein level). Expressed in fetal erythroid tissue. In PubMed:8114710 authors noted that a 10-fold molar excess of isoform 3 over isoform 1 inhibited DNA-binding. Belongs to the grh/CP2 family. CP2 subfamily.