Acts as a transcriptional activator or repressor. When overexpressed, represses anti-oxidant response element (ARE)-mediated transcription. Involved either as an oncogene or as a tumor suppressor, depending on the cell context. Binds to the ARE sites of detoxifying enzyme gene promoters. Involved in embryonic lens fiber cell development. Recruits the transcriptional coactivators CREBBP and/or EP300 to crystallin promoters leading to up-regulation of crystallin gene during lens fiber cell differentiation. Activates the expression of IL4 in T-helper 2 (Th2) cells. Increases T-cell susceptibility to apoptosis by interacting with MYB and decreasing BCL2 expression. Together with PAX6, transactivates strongly the glucagon gene promoter through the G1 element. Activates transcription of the CD13 proximal promoter in endothelial cells. Represses transcription of the CD13 promoter in early stages of myelopoiesis by affecting the ETS1 and MYB cooperative interaction. Involved in the initial chondrocyte terminal differentiation and the disappearance of hypertrophic chondrocytes during endochondral bone development. Binds to the sequence 5'-[GT]G[GC]N[GT]NCTCAGNN-3' in the L7 promoter. Binds to the T-MARE (Maf response element) sites of lens-specific alpha- and beta-crystallin gene promoters. Binds element G1 on the glucagon promoter. Binds an AT-rich region adjacent to the TGC motif (atypical Maf response element) in the CD13 proximal promoter in endothelial cells. It may interact with additional basic-zipper proteins that determine a subtype of Maf-responsive element binding (By similarity). Homodimer or heterodimer with other bHLH-Zip transcription factors. Binds DNA as a homodimer or as a heterodimer. Heterotetramer of two MAF and two USF2. Interacts with PAX6; the interaction is direct. Interacts with MYB; interaction takes place weakly in normal T-cells and increases in T-cells following stimulation through the TCR engagement. Interacts with MYB; the ternary complex formed with MYB and the CD13 promoter is regulated in response to differentiating signals. Interacts with USF2; the interaction inhibits its DNA-binding activity on the L7 promoter. Interacts with CREBBP, EP300 and ETS1 (By similarity). Ubiquitinated, leading to its degradation by the proteasome. Ubiquitination is triggered by glucocorticoids (By similarity). Phosphorylated by GSK3 and MAPK13 on serine and threonine residues (Probable). The phosphorylation status can serve to either stimulate or inhibit transcription (By similarity). Belongs to the bZIP family. Maf subfamily.