This region is found to the N-terminus of the pfam00170 transcription factor domain. It is between 150 and 200 amino acids in length. The N-terminal half is rather rich in proline residues and has been termed the PRD (proline rich domain), whereas the C-terminal half is more polar and has been called the MFMR (multifunctional mosaic region). It has been suggested that this family is composed of three sub-families called A, B and C, classified according to motif composition. It has been suggested that some of these motifs may be involved in mediating protein-protein interactions. The MFMR region contains a nuclear localization signal in bZIP opaque and GBF-2. The MFMR also contains a transregulatory activity in TAF-1. The MFMR in CPRF-2 contains cytoplasmic retention signals.