Transcription factor MafG （MAFG） is a member of the Maf family. Given that they lack a putative transactivation domain， the small Mafs act as transcriptional repressors when they dimerize amongst themselves. Nevertheless， they seem to function as transcriptional activators by dimerizing with other （generally larger） basic-zipper proteins and engaging them to specific DNA-binding sites. Small Maf proteins heterodimerize with Fos and may function as competitive repressors of the NF-E2 transcription factor.
