Oestrogen receptor

Oestrogen receptor (ER) is a group of proteins found inside cells. They are receptors that are activated by the hormone oestrogen (estradiol). Two classes of oestrogen receptor exist: ER alpha and ER beta. Both are products of different genes and have different functions based on the context.

Structure

The oestrogen receptor, like other members of the nuclear receptor family, has modular structure and contains the following domains:

• A/B domain: This is the N-terminal regulatory domain.
• C domain: This is the DNA-binding domain (DBD).
• D domain: This is the hinge region.
• E/F domain: This is the ligand binding domain (LBD).

Function

Oestrogen receptors act as ligand-activated transcription factors and regulate gene expression. When oestrogen binds to the receptor, it results in a conformational change in the receptor. This change allows dimerization and binding of the receptor to specific sequences of DNA known as hormone response elements (HREs). The DNA/receptor complex then recruits other proteins that are responsible for the transcription of downstream DNA into mRNA and eventually protein synthesis.

Clinical significance

Oestrogen receptors have a significant role in the regulation of the menstrual cycle and they have implications in breast cancer, endometrial cancer, and osteoporosis. They are an important receptor in the body's response to oestrogen and are a target for many drugs, such as tamoxifen and raloxifene.

See also

• Oestrogen
• Hormone response element
• Tamoxifen
• Raloxifene