Estrogen receptor alpha–glucocorticoid receptor interface (ERα–GR interface)

The Estrogen receptor alpha–glucocorticoid receptor (ERα–GR) interface is a protein-protein interaction site that facilitates molecular crosstalk between the estrogen receptor alpha (ESR1) and the glucocorticoid receptor (NR3C1). In ER-positive breast cancer, this interface is primarily formed when ligand-activated GR binds directly to ERα, often mediated by the GR DNA-binding domain and the ERα transcriptional complex. Specifically, residue Arginine 488 in the GR DNA-binding domain has been identified as a critical stabilizer of this interaction (Karmakar et al., 2013). This interaction allows GR to tether to ERα-binding regions on the genome, where it displaces ERα and its associated coactivators like SRC-3. This displacement leads to the transcriptional repression of pro-proliferative estrogen-target genes, such as Cyclin D1 (CCND1), thereby inhibiting tumor cell growth (Tonsing-Carter et al., 2019). Consequently, the ERα–GR interface serves as a therapeutic node where glucocorticoids can antagonize estrogen-driven proliferation, offering a strategy to enhance endocrine therapy or combat resistance. However, the role of this interface is highly context-dependent, as GR signaling can have opposing effects in different breast cancer subtypes or tissues like the endometrium (Vander Ark et al., 2018). Understanding and targeting this specific interface provides a pathway for developing allosteric modulators or peptidomimetics that could mimic the anti-proliferative effects of glucocorticoids while minimizing systemic side effects.

Other names

ER-GR interfaceESR1-NR3C1 interfaceEstrogen receptor 1–Glucocorticoid receptor interfaceERα-GR crosstalk interface

Glucocorticoid receptor agonists promote the physical association of GR with ERα, leading to the displacement of ERα from its genomic binding sites and the subsequent repression of estrogen-responsive genes.