Forkhead (FH) domain found in the Forkhead box protein A (FOXA) subfamily
The FOXA subfamily includes three winged helix transcription factors, FOXA1 (also called hepatocyte nuclear factor 3-alpha or transcription factor 3A), FOXA2 (also called hepatocyte nuclear factor 3-beta or transcription factor 3B), and FOXA3 (also called hepatocyte nuclear factor 3-gamma or transcription factor 3G). FOXA1 is essential for epithelial lineage differentiation and has been found to be upregulated in numerous cancers. FOXA2 controls cell differentiation. It is a key transcriptional regulator that maintains airway mucus homeostasis and may also have an important role in bone metabolism. FOXA3 acts as an essential transcriptional regulator engaged in adipogenesis and energy metabolism. This subfamily also includes Xenopus tropicalis FOXA4, Drosophila melanogaster protein fork head (dFKH), and similar proteins. FOXA4 is only present in amphibians, where it is required for the correct regionalization and maintenance of the central nervous system. dFKH promotes terminal as opposed to segmental development. In the absence of dFKH, this developmental switch does not occur. The FH domain is a winged helix DNA-binding domain. FOX transcription factors recognize the core sequence 5'-(A/C)AA(C/T)A-3'.