Enables protein heterodimerization activity. Contributes to sequence-specific DNA binding activity. Involved in determination of adult lifespan and regulation of cell differentiation. Located in nucleus. Part of transcription regulator complex. Expressed in body wall musculature; neurons; pharynx; and somatic nervous system. Used to study Parkinson's disease. Human ortholog(s) of this gene implicated in neurofibrosarcoma and prostate cancer. Is an ortholog of human MXI1 (MAX interactor 1, dimerization protein).