Steroid receptors belong to the type I receptors of the nuclear receptor family. Main ligands for steroid receptors are steroids such as corticosteroids, estrogens, androgens, and progestagens. Steroid receptors are localized in the cytoplasm mostly in complexes with heat shock proteins (HSP). Steroid-like compounds can easily pass the cell membrane due to their lipophilic properties and thus reach the receptors.
When the ligand binds to the receptor, the receptor undergoes a conformational change and the heat shock proteins come off. Upon binding the receptors translocate to the nucleus, and bind as homodimers to a specific response element (RE). This leads to activation or repression of gene transcription. Steroid receptors thus act as transcription factors.