scholarly journals Disruption of estrogen receptor DNA-binding domain and related intramolecular communication restores tamoxifen sensitivity in resistant breast cancer

Cancer Cell ◽  
2006 ◽  
Vol 10 (6) ◽  
pp. 487-499 ◽  
Author(s):  
Li Hua Wang ◽  
Xiao Yi Yang ◽  
Xiaohu Zhang ◽  
Ping An ◽  
Han-Jong Kim ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Estrogen Receptor ◽  
Dna Binding ◽  
Binding Domain ◽  
Dna Binding Domain ◽  
Intramolecular Communication ◽  
Tamoxifen Sensitivity

scholarly journals Modulation of Runx2 Activity by Estrogen Receptor-α: Implications for Osteoporosis and Breast Cancer

Endocrinology ◽  
2008 ◽  
Vol 149 (12) ◽  
pp. 5984-5995 ◽  
Author(s):  
Omar Khalid ◽  
Sanjeev K. Baniwal ◽  
Daniel J. Purcell ◽  
Nathalie Leclerc ◽  
Yankel Gabet ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Estrogen Receptor ◽  
Dna Binding ◽  
Transcriptional Activation ◽  
Target Genes ◽  
Estrogen Receptor Α ◽  
Binding Domain ◽  
Breast Epithelial Cell ◽  
Dependent Manner ◽  
Dna Binding Domain

The transcription factors Runx2 and estrogen receptor-α (ERα) are involved in numerous normal and disease processes, including postmenopausal osteoporosis and breast cancer. Using indirect immunofluorescence microscopy and pull-down techniques, we found them to colocalize and form complexes in a ligand-dependent manner. Estradiol-bound ERα strongly interacted with Runx2 directly through its DNA-binding domain and only indirectly through its N-terminal and ligand-binding domains. Runx2’s amino acids 417–514, encompassing activation domain 3 and the nuclear matrix targeting sequence, were sufficient for interaction with ERα’s DNA-binding domain. As a consequence of the interaction, Runx2’s transcriptional activation activity was strongly repressed, as shown by reporter assays in COS7 cells, breast cancer cells, and late-stage MC3T3-E1 osteoblast cultures. Metaanalysis of gene expression in 779 breast cancer biopsies indicated negative correlation between the expression of ERα and Runx2 target genes. Selective ER modulators (SERM) induced ERα-Runx2 interactions but led to various functional outcomes. The regulation of Runx2 by ERα may play key roles in osteoblast and breast epithelial cell growth and differentiation; hence, modulation of Runx2 by native and synthetic ERα ligands offers new avenues in selective ER modulator evaluation and development.

Binding of the estrogen receptor DNA-binding domain to the estrogen response element induces DNA bending

1992 ◽  
Vol 12 (5) ◽  
pp. 2037-2042
Author(s):  
A M Nardulli ◽  
D J Shapiro
Keyword(s):  
Estrogen Receptor ◽  
Dna Binding ◽  
Dna Bending ◽  
Binding Domain ◽  
Estrogen Response Element ◽  
Dna Binding Domain ◽  
Mobility Shift ◽  
Response Element ◽  
Estrogen Response ◽  
Dna Fragment

We have used circular permutation analysis to determine whether binding of purified Xenopus laevis estrogen receptor DNA-binding domain (DBD) to a DNA fragment containing an estrogen response element (ERE) causes the DNA to bend. Gel mobility shift assays showed that DBD-DNA complexes formed with fragments containing more centrally located EREs migrated more slowly than complexes formed with fragments containing EREs near the ends of the DNA. DNA bending standards were used to determine that the degree of bending induced by binding of the DBD to an ERE was approximately 34 degrees. A 1.55-fold increase in the degree of bending was observed when two EREs were present in the DNA fragment. These in vitro studies suggest that interaction of nuclear receptors with their hormone response elements in vivo may result in an altered DNA conformation.

scholarly journals Prebending the estrogen response element destabilizes binding of the estrogen receptor DNA binding domain.

1997 ◽  
Vol 17 (6) ◽  
pp. 3173-3180 ◽  
Author(s):  
J Kim ◽  
G de Haan ◽  
A M Nardulli ◽  
D J Shapiro
Keyword(s):  
Estrogen Receptor ◽  
Transcription Factor ◽  
Dna Binding ◽  
Minor Groove ◽  
Dna Topology ◽  
Binding Domain ◽  
Dna Binding Domain ◽  
Eukaryotic Transcription ◽  
Estrogen Response ◽  
Direct Demonstration

Binding of many eukaryotic transcription regulatory proteins to their DNA recognition sequences results in conformational changes in DNA. To test the effect of altering DNA topology by prebending a transcription factor binding site, we examined the interaction of the estrogen receptor (ER) DNA binding domain (DBD) with prebent estrogen response elements (EREs). When the ERE in minicircle DNA was prebent toward the major groove, which is in the same direction as the ER-induced DNA bend, there was no significant effect on ER DBD binding relative to the linear counterparts. However, when the ERE was bent toward the minor groove, in a direction that opposes the ER-induced DNA bend, there was a four- to eightfold reduction in ER DBD binding. Since reduced binding was also observed with the ERE in nicked circles, the reduction in binding was not due to torsional force induced by binding of ER DBD to the prebent ERE in covalently closed minicircles. To determine the mechanism responsible for reduced binding to the prebent ERE, we examined the effect of prebending the ERE on the association and dissociation of the ER DBD. Binding of the ER DBD to ERE-containing minicircles was rapid when the EREs were prebent toward either the major or minor groove of the DNA (k(on) of 9.9 x 10(6) to 1.7 x 10(7) M(-1) s(-1)). Prebending the ERE toward the minor groove resulted in an increase in k(off) of four- to fivefold. Increased dissociation of the ER DBD from the ERE is, therefore, the major factor responsible for reduced binding of the ER DBD to an ERE prebent toward the minor groove. These data provide the first direct demonstration that the interaction of a eukaryotic transcription factor with its recognition sequence can be strongly influenced by altering DNA topology through prebending the DNA.

scholarly journals Phosphorylation of Human Estrogen Receptor α by Protein Kinase A Regulates Dimerization

1999 ◽  
Vol 19 (2) ◽  
pp. 1002-1015 ◽  
Author(s):  
Dongsheng Chen ◽  
Paul E. Pace ◽  
R. Charles Coombes ◽  
Simak Ali
Keyword(s):  
Estrogen Receptor ◽  
Protein Kinase ◽  
Dna Binding ◽  
Ligand Binding ◽  
Protein Kinase A ◽  
Estrogen Receptor Α ◽  
Binding Domain ◽  
Dna Binding Domain ◽  
Ici 182,780 ◽  
Kinase A

ABSTRACT Phosphorylation provides an important mechanism by which transcription factor activity is regulated. Estrogen receptor α (ERα) is phosphorylated on multiple sites, and stimulation of a number of growth factor receptors and/or protein kinases leads to ligand-independent and/or synergistic increase in transcriptional activation by ERα in the presence of estrogen. Here we show that ERα is phosphorylated by protein kinase A (PKA) on serine-236 within the DNA binding domain. Mutation of serine-236 to glutamic acid prevents DNA binding by inhibiting dimerization by ERα, whereas mutation to alanine has little effect on DNA binding or dimerization. Furthermore, PKA overexpression or activation of endogenous PKA inhibits dimerization in the absence of ligand. This inhibition is overcome by the addition of 17β-estradiol or the partial agonist 4-hydroxy tamoxifen. Interestingly, treatment with the complete antagonist ICI 182,780 does not overcome the inhibitory effect of PKA activation. Our results indicate that in the absence of ligand ERα forms dimers through interaction between DNA binding domains and that dimerization mediated by the ligand binding domain only occurs upon ligand binding but that the complete antagonist ICI 182,780 prevents dimerization through the ligand-binding domain. Heterodimer formation between ERα and ERβ is similarly affected by PKA phosphorylation of serine 236 of ERα. However, 4-hydroxytamoxifen is unable to overcome inhibition of dimerization by PKA. Thus, phosphorylation of ERα in the DNA binding domain provides a mechanism by which dimerization and thereby DNA binding by the estrogen receptor is regulated.

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