Maf transcription factors form a distinct family of the basic leucine zipper (bZip) transcription factors. The Maf family is divided into two subclasses, large Mafs and small Mafs (MafF, MafK []and MafG []). Both subclasses contain leucine-zipper motifs, which allow homodimerisation as well as heterodimerisation with a variety of other bZip proteins. Small Mafs can act as negative regulators of transcription by recruiting transcriptional repressors or by forming homodimers that can then displace active dimers. Small Mafs lack a transactivator domain, but they can also serve as transcriptional activators by dimerising with other (usually larger) basic-zipper proteins and recruiting them to specific DNA-binding sites.The small Mafs (MafF, MafG and MafK) appear to be crucial regulators of mammalian gene expression. Small Mafs are also involved in regulating stress response and detoxification pathways [].
Maf transcription factors form a distinct family of the basic leucine zipper (bZip) transcription factors. The Maf family is divided into two subclasses, large Mafs (c-maf, mafB, and mafA/L-maf, nrl) and small Mafs (MafF, MafK and MafG). Both subclasses contain leucine-zipper motifs, which allow homodimerisation as well as heterodimerisation with a variety of other bZip proteins. In contrast to the small Mafs, the large Maf proteins contain a transactivator domain in their amino terminus.MafB plays critical roles in a variety of cellular differentiation processes, including in kidney podocytes [], macrophages [, ], and pancreatic islet alpha and beta-cells, which are responsible for the production of the hormones glucagon and insulin respectively. MafB is also expressed in alpha-cells in adult pancreas and is important for their function [, , , ].Mutations in Maf gene cause multicentric carpotarsal osteolysis syndrome (MCTO), which is a rare skeletal disorder, usually presenting in early childhood with a clinical picture mimicking juvenile rheumatoid arthritis [].
Maf transcription factors form a distinct family of the basic leucine zipper (bZip) transcription factors. The Maf family is divided into two subclasses, large Mafs (c-maf, mafB, and mafA/L-maf, Nrl) and small Mafs (MafF, MafK and MafG). Both subclasses contain leucine-zipper motifs, which allow homodimerisation as well as heterodimerisation with a variety of other bZip proteins. In contrast to the small Mafs, the large Maf proteins contain a transactivator domain in their amino terminus.Neural retina-specific leucine zipper protein (Nrl) is a member of the Maf family of transcription factors that regulates the expression of rod-specific genes, including rhodopsin [, , ]. Mutations in Nrl cause retinitis pigmentosa 27 (RP27), which is a retinal dystrophy belonging to the group of pigmentary retinopathies [, ], and retinal degeneration autosomal recessive clumped pigment type (RDCP), which is a retinopathy characterised by night blindness since early childhood, consistent with a severe reduction in rod function [].
Maf transcription factors form a distinct family of the basic leucine zipper (bZip) transcription factors. The Maf family is divided into two subclasses, large Mafs (c-maf, mafB, and mafA/L-maf, nrl) and small Mafs (MafF, MafK and MafG). Both subclasses contain leucine-zipper motifs, which allow homodimerisation as well as heterodimerisation with a variety of other bZip proteins. In contrast to the small Mafs, the large Maf proteins contain a transactivator domain in their amino terminus []. The small Maf proteins might contribute to oncogenic processes by participating in antioxidant responses, while large Maf proteins have been directly implicated in carcinogenesis []. This entry represents MafA. MafA plays a critical role in the regulation of crystalline genes and lens development [, ]. It also binds the insulin enhancer element RIPE3b and regulates the insulin gene transcription [, , ].
Maf transcription factors form a distinct family of the basic leucine zipper (bZip) transcription factors []. The Maf family is divided into two subclasses, large Mafs and small Mafs (MafF, MafK []and MafG []). Both subclasses contain leucine-zipper motifs, which allow homodimerisation as well as heterodimerisation with a variety of other bZip proteins. Small Mafs can act as negative regulators of transcription by recruiting transcriptional repressors or by forming homodimers that can then displace active dimers. Small Mafs lack a transactivator domain, but they can also serve as transcriptional activators by dimerising with other (usually larger) basic-zipper proteins and recruiting them to specific DNA-binding sites. This entry represents MafG. The p45/MafG heterodimer plays a role in the regulation of erythropoiesis []and may be involved in signal transduction of extracellular H+ []. MAFG is up-regulated in smokers [].
BACH proteins are Cap'n'Collar (CNC) Basic leucine zipper (bZIP) transcription factors that are defined by a conserved 43-amino acid region (called the CNC domain) located N-terminal to the bZIP DNA-binding domain. In addition, they contain a BTB domain (Broad complex-Tramtrack-Bric-a-brac domain, also known as the POZ [poxvirus and zinc finger]domain) that is absent in other CNC proteins. Veterbrates contain two members, BACH1 and BACH2. BACH1 forms heterodimers with small Mafs such as MafK to function as a repressor of heme oxygenase-1 (HO-1) gene (Hmox-1) enhancers []. It has also been implicated as the master regulator of breast cancer bone metastasis []. The BACH1 bZIP transcription factor should not be confused with the protein originally named as BRCA1-Associated C-terminal Helicase1 (BACH1), which has been renamed BRIP1 (BRCA1 Interacting Protein C-terminal Helicase1) and also called FANCJ. BACH2 is a B-cell specific transcription factor that plays a critical role in oxidative stress-mediated apoptosis []. It plays an important role in class switching and somatic hypermutation of immunoglobulin genes [].
