Exploring the Spatial Landscape of the Estrogen Receptor Proximal Proteome With Antibody-Based Proximity Labeling

Estrogen Receptor-α (ERα) plays a crucial role in breast cancer, driving the transcription of genes involved in tumor progression. The ERα function is dependent on multiple protein-protein interactions (PPIs). As a result of rapid tumor adaptation, these are often altered by drug treatments and acquired mutations. Although elucidating how ERα PPIs evolve in response to therapies is critical to fully uncover drug resistance, capturing transient interactions in their subcellular context remains a major challenge. In this study, we used Biotinylation by Antibody Recognition (BAR) coupled with mass spectrometry to investigate the ERα proximal proteome and its perturbations associated with endocrine resistance.