Thyroid transcription factor 2 (TITF2; Forkhead; TH; also known as a "winged helix") . FH is named for the Drosophila fork head protein, a transcription factor which promotes terminal rather than segmental development. This family of transcription factor domains, which bind to B-DNA as monomers, are also found in the Hepatocyte nuclear factor (HNF) proteins, which provide tissue-specific gene regulation. The structure contains 2 flexible loops or "wings" in the C-terminal region, hence the term winged helix. Transcription factor that binds and activates the promoter of thyroid specific genes such as thyroglobulin, thyroperoxidase, and thyrotropin receptor. Crucial in the maintenance of the thyroid differentiation phenotype. May play a role in lung development and surfactant homeostasis. TISSUE SPECIFICITY: Thyroid and lung. subcellular location: Nucleus Belongs to the NK-2 homeobox family.