The N-terminal regions of estrogen receptor alpha and beta are unstructured in vitro and show different TBP binding properties

Citation
A. Warnmark et al., The N-terminal regions of estrogen receptor alpha and beta are unstructured in vitro and show different TBP binding properties, J BIOL CHEM, 276(49), 2001, pp. 45939-45944
Citations number
50
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Biochemistry & Biophysics
Journal title
JOURNAL OF BIOLOGICAL CHEMISTRY
ISSN journal
0021-9258 → ACNP
Volume
276
Issue
49
Year of publication
2001
Pages
45939 - 45944
Database
ISI
SICI code
0021-9258(200112)276:49<45939:TNROER>2.0.ZU;2-B
Abstract
The N-terminal regions of the estrogen receptor ve (ER alpha -N) and beta ( ER beta -N) were expressed and purified to homogeneity. Using NAM and circu lar dichroism spectroscopy, we conclude that both ER alpha -N and ER beta - N are unstructured in solution. The TATA box-binding protein (TBP) has been shown previously to interact with ERa-N in vitro and to potentiate ER-acti vated transcription. We used surface plasmon resonance and circular dichroi sm spectroscopy to confirm and further characterize the ER-N-TBP interactio n. Our results show that the intrinsically unstructured ERa-N interacts wit h TBP, and suggest that structural changes are induced in ERa-N upon TBP in teraction. Conformational changes upon target factor interaction have not p reviously been demonstrated for any N-terminal region of nuclear receptors. In addition, no binding of ER beta -N to TBP was detected. This difference in TBP binding could imply differential recruitment of target proteins by ERa-N and ER beta -N. The affinity of the ER alpha -N-TBP interaction was d etermined to be in the micromolar range (K-D = 10(-6) to 10(-5) m). Our res ults support models of TBP as a target protein for the N-terminal activatio n domain of ER alpha. Further, our results suggest that target proteins can induce and/or stabilize ordered structure in N-terminal regions of nuclear receptors upon interaction.