MAFK

The developmentally regulated expression of the globin genes depends on upstream regulatory elements termed locus control regions (LCRs). LCRs are associated with powerful enhancer activity that is mediated by the transcription factor NFE2 (nuclear factor erythroid-2). NFE2 recognition sites are also present in the gene promoters of 2 heme biosynthetic enzymes, porphobilinogen deaminase (PBGD; MIM 609806) and ferrochelatase (FECH; MIM 612386). NFE2 DNA-binding activity consists of a heterodimer containing an 18-kD Maf protein (MafF, MafG (MIM 602020), or MafK) and p45 (MIM 601490). Both subunits are members of the activator protein-1 superfamily of basic leucine zipper (bZIP) proteins (see MIM 165160). Maf homodimers suppress transcription at NFE2 sites.

Full Name

MAF BZIP TRANSCRIPTION FACTOR K

Function

Since they lack a putative transactivation domain, the small Mafs behave as transcriptional repressors when they dimerize among themselves (PubMed:9150357).
However, they act as transcriptional activators by dimerizing with other (usually larger) basic-zipper proteins, such as NFE2, NFE2L1/NRF1, NFE2L2/NRF2 and NFE2L3/NRF3, and recruiting them to specific DNA-binding sites (PubMed:9150357, PubMed:8932385).
Small Maf proteins heterodimerize with Fos and may act as competitive repressors of the NF-E2 transcription factor (PubMed:9150357).

Biological Process

Negative regulation of transcription by RNA polymerase IIManual Assertion Based On ExperimentIDA:NTNU_SB
Regulation of transcription by RNA polymerase IIManual Assertion Based On ExperimentIBA:GO_Central

Cellular Location

Nucleus