DNA-binding protein that binds to the 5'GGGAATRCC-3' Ikaros- binding sequence. Transcriptional repressor. Interacts with SPI1 and MITF to repress transcription of the CTSK and ACP5 promoters via recruitment of corepressors SIN3A and CTBP2. May be involved in the development of central and peripheral nervous systems. Essential for the inhibitory function of regulatory T-cells (Treg). Mediates FOXP3- mediated gene silencing in regulatory T-cells (Treg) via recruitment of corepressor CTBP1 (By similarity). {ECO:0000250|UniProtKB:Q8C208, ECO:0000269|PubMed:10978333, ECO:0000269|PubMed:12015313, ECO:0000269|PubMed:12444977}. This is the function of ENSG00000123411 (IKZF4, IKAROS family zinc finger 4).