芳香化酶是体内催化雌激素合成的关键酶，调控其活性是治疗乳腺癌等雌激素相关疾病的重要手段。目前对芳香化酶的降解途径缺乏了解，限制了对其组织选择性表达调控机制的认识。我们前期发现天然产物木犀草素可能通过蛋白激酶A（PKA）促进了芳香化酶蛋白质降解。因此，为了研究PKA介导的磷酸化在调控芳香化酶降解中的作用机制，本课题拟以木犀草素为探针，通过构效关系研究，分离和鉴定其作用靶标；明确26S蛋白酶体在芳香化酶降解中的作用，发现泛素化在介导芳香化酶降解中的功能，确定其泛素化位点；研究PKA介导的磷酸化在调控芳香化酶泛素化降解中的作用机制，鉴定其磷酸化位点；研究木犀草素靶蛋白对PKA介导的芳香化酶磷酸化和泛素化的影响和作用机制，评价木犀草素及其靶蛋白对乳腺癌细胞增殖迁移以及体内肿瘤形成的影响。旨在明确泛素/26S蛋白酶体途径在调控芳香化酶降解中的作用，发现PKA介导的磷酸化在调控芳香化酶降解中的新机制。

Regulation of aromatase, the key enzyme in estrogen biosynthesis, is an important strategy in the treatment of estrogen-related diseases such as breast cancer. However, aromatase protein degradation pathway and its mechanism still remain unknown, which limites our understanding of tissue specificity of aroamtase expression. Previously we found that luteolin, a natural product, can promote aromatase protein degradation possibly through cAMP-PKA（protein kinase A） signaling pathway. In order to study the molecular mechanism of PKA-mediated phosphorylation on aromatase protein degradation, we will use luteolin as a probe to study its structure-activity relationship to increase its activity and specificity in promoting aromatase protein degradation, and synthesize the luteolin with affinity tag to isolate its target; clarify the role of 26S proteasome in aromatase degradation, find the function of ubiquitinaiton in the regulaiton of aromatase degradation and identify its ubiquitination sites; study the mechanism of PKA-mediated phosphorylaiton on aromatase ubiquitination and degradation, and identify its phosphorylaiton sites; study the effect and mechanism of luteolin targeted protein on PKA-mediated aromatase phosphorylation and ubiquitination, and evaluate the effects of luteolin and its target protein on the proliferation, metastasis and tumorigenesis of breast cancer cells in vitro and in vivo. The purpose of this study is to elucidate the role of ubiquitin/26S proteasome pathway in the regulation of aromatase degradation and find the new mechanism of PKA-mediated phosphorylation in the regulation of aromatase degradation.