Since it lacks a putative transactivation domain, it may behave as a transcriptional repressor when it dimerize among himself. May also serve as a transcriptional activator by dimerizing with other (usually larger) basic-zipper proteins and recruiting them to specific DNA-binding sites. May be involved in the cellular stress response. Monomer and homo- or heterodimer. Highly expressed in the ovary, lower expression in the brain, heart and mesenterium. Belongs to the bZIP family. Maf subfamily.