MAF is a bZIP transcription factor that functions as a context-dependent regulator of gene expression across diverse biological processes. In lens development, MAF recruits coactivators CREBBP and EP300 to crystallin promoters, driving crystallin expression during fiber cell differentiation 1. MAF also regulates immune responses by co-dominantly controlling IL-10 expression in effector T cells while repressing proinflammatory cytokines; MAF-deficient mice show increased type 17 responses and susceptibility to colitis 2. In skeletal muscle, MAF maintains fast-twitch fiber identity and muscle mass by repressing atrophic genes; MAF repression during denervation or amyotrophic lateral sclerosis drives muscle atrophy, while MAF overexpression prevents this loss 3. MAF regulates epidermal differentiation as part of a dynamic gene regulatory network, acting downstream of lncRNAs and upstream of differentiation genes 4. Clinically, MAF mutations cause Aymé-Gripp syndrome, characterized by congenital cataracts, hearing loss, intellectual disability, and facial abnormalities 5. In cancer, MAF amplification promotes breast cancer metastasis through interactions with estrogen receptor alpha and epigenetic remodeling 6, while in multiple myeloma, the SAGA complex maintains MAF-driven oncogenic gene expression programs 78. Thus MAF functions as both a developmental regulator and context-dependent oncogene.