Subtype-specific modulation of estrogen receptor-coactivator interaction by phosphorylation.
The estrogen receptor (ER) is the number one target for the treatment of endocrine responsive breast cancer and remains a highly attractive target for new drug development. Despite considerable efforts to understand the role of ER post-translational modifications (PTMs), the complexity of these modifications and their impact, at the molecular level, are poorly understood. Using a chemical biology approach, fundamentally rooted in an efficient protein semisynthesis of tyrosine phosphorylated ER constructs, the complex role of the ER tyrosine phosphorylation is addressed here for the first time on a molecular level. The semisynthetic approach allows for the site-specific introduction of PTMs as well as biophysical probes. A combination of biophysical techniques, including NMR, with molecular dynamics studies reveals the role of the phosphorylation of the clinically relevant tyrosine 537 (Y537) in ERα and the analogous tyrosine (Y488) in ERβ. Phosphorylation has important effects on the dynamics of the ER Helix 12, which is centrally involved in receptor activity regulation, and on its interplay with ligand and cofactor binding, but with differential regulatory effects of the analogous PTMs on the two ER subtypes. Combined, the results bring forward a novel molecular model of a phosphorylation-induced subtype specific ER modulatory mechanism, alternative to the widely accepted ligand-induced activation mechanism.
Laboratory of Chemical Biology and Institute of Complex Molecular Systems, Department of Biomedical Engineering, Eindhoven University of Technology , Den Dolech 2, 5612AZ Eindhoven, The Netherlands.
Inga M
IM
Tharun
Lidia
L
Nieto
Christian
C
Haase
Marcel
M
Scheepstra
Mark
M
Balk
Sabine
S
Möcklinghoff
Wencke
W
Adriaens
Sonja A
SA
Dames
Luc
L
Brunsveld
D001665:Binding Sites; D008958:Models, Molecular; D056918:Nuclear Receptor Coactivators / Q000737:chemistry / Q000378:metabolism*; D010766:Phosphorylation; D011485:Protein Binding; D011487:Protein Conformation; D017434:Protein Structure, Tertiary; D011960:Receptors, Estrogen / Q000737:chemistry / Q000378:metabolism*
D056918:Nuclear Receptor Coactivators; D011960:Receptors, Estrogen