Efficient Labeling of Estrogen Receptor α Inside Cells using Affimer, an Antibody Mimetic

Estrogen receptor α (ERα) is expressed in around 80% of breast cancers and is associated with proliferation and tumor growth. Mutations in ERα, like Y537S, are associated with driving metastasis and poor disease-free survival. However, the interaction of ERα with different ligands remain to be fully understood. Here we use a small antibody mimetic, a 13 kDa anti-ERα affimer conjugated to an organic fluorophore (Alexa647), to label a cell...