The receptor also interacts with activator protein 1 and Sp-1 to promote transcription, via several coactivators such as PELP-1

Genomic

Since estrogen is a steroidal hormone, it can pass through the phospholipid membranes of the cell, and receptors therefore do not need to be membrane-bound in order to bind with estrogen.

Signal transduction

The ERs are regarded to be cytoplasmic receptors in their unliganded state, but visualization research has shown that a fraction of the ERs resides in the nucleus.

Distribution

Both ERs are widely expressed in different tissue types, however there are some notable differences in their expression patterns:

• The ERα is found in endometrium, breast cancer cells, ovarian stroma cells, and the hypothalamus. In males, ERα protein is found in the epithelium of the efferent ducts.
• The expression of the ERβ protein has been documented in kidney, brain, bone, heart, lungs, intestinal mucosa, prostate, and endothelial cells.

In the absence of hormone, estrogen receptors are largely located in the cytosol. Hormone binding to the receptor triggers a number of events starting with migration of the receptor from the cytosol into the nucleus, dimerization of the receptor, and subsequent binding of the receptor dimer to specific sequences of DNA known as hormone response elements. The DNA/receptor complex then recruits other proteins that are responsible for the transcription of downstream DNA into mRNA and finally protein that results in a change in cell function. Estrogen receptors also occur within the cell nucleus, and both estrogen receptor subtypes have a DNA-binding domain and can function as transcription factors to regulate the production of proteins.

Дата добавления: 2014-01-14