Transcriptional repressor. Binds with MAX to form a sequence- specific DNA-binding protein complex which recognizes the core sequence 5'-CAC[GA]TG-3'. Antagonizes MYC transcriptional activity by competing for MAX and suppresses MYC dependent cell transformation (By similarity). . This is the function of Ensembl gene identifier ENSG00000123933 (MXD4, MAX dimerization protein 4).