Anti-TEF antibodies are used in the immunodetection of the protein TEF transcription factor, PAR bZIP family member. In humans, the canonical protein has a reported length of 303 amino acid residues and a mass of 33.2 kDa. Its subcellular localization is in the nucleus. Alternative splicing is reported to yield 2 different isoforms for this protein. A member of a the BZIP protein family, TEF is reported to be a transcription factor that binds to and transactivates the TSHB promoter. Synonyms for this target antigen include TEF, PAR bZIP transcription factor, thyrotrophic embryonic factor, and thyrotroph embryonic factor.