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.