basic helix-loop-helix (bHLH) domain found in E proteins family
The E proteins family corresponds to class I bHLH proteins, which are widely expressed within the immune system and on which the majority of this chapter will be focused. Members in this family include E2A (also referred to as TCF-3), E47, TCF-12 (also referred to as HEB), and TCF-4 (also referred to as E2-2) in vertebrates, as well as the E protein ortholog, Daughterless (Da), from Drosophila melanogaster. E-proteins are expressed broadly and in certain complexes they are restricted to specific cell types. E-proteins homodimerize and heterodimerize with the tissue specific bHLH factors to bind DNA and regulate transcription and differentiation of cells during development. The activity of the E-proteins is regulated by two main mechanisms: first, the relative concentrations of E-proteins, tissue specific bHLH factors, and the Id proteins, and second, covalent modification.
Jiyao W et al.(2023). "The conserved domain database in 2023.",