Figure 1. . Classical and nonclassical and legend-independent mode of nuclear-initiated steroid signaling.
ER, in its classical mode action (A), directly binds to specific DNA response elements called EREs. Estrogen(E2)-bound ER generally recruits CoA complexes to induce gene transcription. In ERs nonclassical mode action (B), ER regulates gene transcription through protein–protein interactions (e.g., with Fos/Jun family members) with other transcription factors, particularly members of the Ap-1 families. In contrast to estrogen-dependent manner of ER action, ER signaling can be activated by phosphorylation at specific ER sites (C). Together, all of these nuclear ER genomic activities are called nuclear-initiated steroid signaling.
CoA: Coactivator; ER: Estrogen receptor; ERE: Estrogen response element.