Multiple domains contribute to the subcellular localization of MondoA-Mlx heterodimers. See text for details. NE, nuclear export receptor; CR, cytoplasmic retention factor; TAD, transcription activation domain; NLS, nuclear localization signal; MCR, Mondo conserved region; DCD, dimerization and cytoplasmic localization domain; bHLHZip, basic region helix-loop-helix leucine zipper domain.