Estrogen receptor alpha interaction with estrogen response element half-sites from the rat prolactin gene

Estrogen regulation of the rat prolactin gene requires sequences within the DNase I hypersensitive site II (HSII). We have used overexpressed mouse estrogen receptor alpha (ERalpha) protein to study interactions of ERalpha with an imperfect estrogen response element (ERE) and four ERE half-site sequences from HSII. We confirmed that ERalpha has higher affinity for ERE half-sites than for the imperfect ERE. As expected, the imperfect ERE formed a complex with ERalpha similar to that between mERalpha and a consensus ERE in gel shift assays. The ERalpha complex with half-sites, however, had faster mobility on a 4% polyacrylamide gel than the ERalpha complex with a consensus ERE, indicating that the complexes had different compositions. Ferguson analysis revealed that the ERalpha/half-site complex had a larger molecular weight and higher negative charge than the ERalpha/consensus ERE complex. Similar results were observed with purified human ERalpha, showing that the ERalpha/half-site complex contained only ERalpha and oligonucleotides. These results are best explained by a model in which a dimer of ERalpha is bound to two half-site oligonucleotides. We propose that two ERalpha dimers may interact with the four ERE half-sites in HSII to influence estrogen regulation of this gene.     

Estrogen receptor phosphorylation

Estrogen receptor alpha (ERalpha) is phosphorylated on multiple amino acid residues. For example, in response to estradiol binding, human ERalpha is predominately phosphorylated on Ser-118 and to a lesser extent on Ser-104 and Ser-106. In response to activation of the mitogen-activated protein kinase pathway, phosphorylation occurs on Ser-118 and Ser-167. These serine residues are all located within the activation function 1 region of the N-terminal domain of ERalpha. In contrast, activation of protein kinase A increases the phosphorylation of Ser-236, which is located in the DNA-binding domain. The in vivo phosphorylation status of Tyr-537, located in the ligand-binding domain, remains controversial. In this review, I present evidence that these phosphorylations occur, and identify the kinases thought to be responsible. Additionally, the functional importance of ERalpha phosphorylation is discussed.     

雌激素β受体和疼痛

雌激素因具有广泛的生物学效应,而日益成为研究的热点。目前已经清楚雌激素通过雌激素α受体所发挥经典作用,但雌激素β受体的具体作用及机制尚不明晰。通过对雌激素β受体的研究发现,其在性别分化、学习和记忆、情绪调控、内分泌,以及生殖行为中均具有重要作用。本文就雌激素β受体与疼痛相关的研究进展作一综述。     

Estrogen receptor variants and mutations

There is a large and increasing body of experimental and clinical data supporting the existence of variant estrogen receptor (ER) proteins in both normal and neoplastic estrogen target tissues, including human breast. Therefore, future examination of ER signal transduction and/or measurement of ER protein must take into account variant ER expression. The functions of variant ER proteins, either physiological or pathological, remain unclear, although a role(s) for some ER variants in breast tumorigenesis and breast cancer progression would be consistent with the accumulated data. Possible tissue specific expression leads to the speculation that ER variants may have a role in tissue specific estrogen action. The following review focuses on the current knowledge available in the scientific literature with respect to the type and characteristics of estrogen receptor variants and mutations that have been identified to occur naturally in tissues and cell lines.