The estrogen receptor is a nuclear receptor that is activated upon ligand binding and subsequently translocates to the nuclear. There, it activates transcription of target genes involved in essential cellular processes. The ER receptor has been implicated in a multitude of diseases, most notably cancer (breast/ovarian).
Proteins on this pathway have targeted assays available via the [CPTAC Assay Portal](https://assays.cancer.gov/available_assays?wp_id=WP2881).