Small Maf proteins (MafF, MafG, MafK): History, structure and function

Gene. 2016 Jul 25;586(2):197-205. doi: 10.1016/j.gene.2016.03.058. Epub 2016 Apr 5.


The small Maf proteins (sMafs) are basic region leucine zipper (bZIP)-type transcription factors. The basic region of the Maf family is unique among the bZIP factors, and it contributes to the distinct DNA-binding mode of this class of proteins. MafF, MafG and MafK are the three vertebrate sMafs, and no functional differences have been observed among them in terms of their bZIP structures. sMafs form homodimers by themselves, and they form heterodimers with cap 'n' collar (CNC) proteins (p45 NF-E2, Nrf1, Nrf2, and Nrf3) and also with Bach proteins (Bach1 and Bach2). Because CNC and Bach proteins cannot bind to DNA as monomers, sMafs are indispensable partners that are required by CNC and Bach proteins to exert their functions. sMafs lack the transcriptional activation domain; hence, their homodimers act as transcriptional repressors. In contrast, sMafs participate in transcriptional activation or repression depending on their heterodimeric partner molecules and context. Mouse genetic analyses have revealed that various biological pathways are under the regulation of CNC-sMaf heterodimers. In this review, we summarize the history and current progress of sMaf studies in relation to their partners.

Keywords: MafF; MafG; MafK; Small Maf; bZIP transcription factor.

Publication types

  • Historical Article
  • Review

MeSH terms

  • Animals
  • DNA / metabolism
  • DNA-Binding Proteins
  • Disease
  • History, 20th Century
  • History, 21st Century
  • Humans
  • MafF Transcription Factor / chemistry
  • MafF Transcription Factor / genetics
  • MafF Transcription Factor / history
  • MafF Transcription Factor / physiology*
  • MafG Transcription Factor / chemistry
  • MafG Transcription Factor / genetics
  • MafG Transcription Factor / history
  • MafG Transcription Factor / physiology*
  • MafK Transcription Factor / chemistry
  • MafK Transcription Factor / genetics
  • MafK Transcription Factor / history
  • MafK Transcription Factor / physiology*
  • Mice
  • Nuclear Proteins / genetics
  • Repressor Proteins / genetics


  • DNA-Binding Proteins
  • MafF Transcription Factor
  • MafG Transcription Factor
  • MafK Transcription Factor
  • Maff protein, mouse
  • Mafg protein, mouse
  • Mafk protein, mouse
  • Nuclear Proteins
  • Repressor Proteins
  • DNA