Roles of Novel Protein Complexes in Estrogen and Progesterone Receptor Signaling

项目总结/摘要 雌激素受体（ER）和孕激素受体（PR）是配体诱导的转录因子。附件 称为辅激活因子的蛋白质调节这些因子的转录激活。已经显示 辅激活因子可增强靶基因的转录，在多种病理过程中发挥重要作用。 过程，如癌症，遗传性遗传疾病，代谢紊乱和炎症。的早期工作 我们的实验室鉴定了E6相关蛋白（E6-AP）作为类固醇激素受体的共激活剂。中 为了鉴定E6-AP相互作用蛋白，我们克隆了WW结构域结合蛋白-2（WBP-2）， 已经表明WBP-2选择性地共激活ER和PR的反式激活功能。 富含聚脯氨酸（PPXY）基序的蛋白质。WBP-2的PPXY基序已被证明参与了 转录激活途径。PPXY基序与含有WW-domain的蛋白质相互作用， PPXY基序和WW结构域（PPXY-WW）复合物，并介导转录刺激。PPXY-WW 在过去的十年里，PPXY-WW复合体在这一过程中扮演了许多新的角色。 细胞核、细胞通路、生理和病理过程才刚刚出现。WWW域名有 在几个关键的调节蛋白上观察到，如yes相关蛋白（YAP 1）和WW-domain- 含有氧化还原酶（WWOX 1）。YAP 1已被证明是几种转录共激活因子， 转录因子，也被归类为癌蛋白，而WWOX 1已被鉴定为 肿瘤抑制因子我们的初步数据表明，致癌YAP 1与WBP-2结合， ER和PR信号。ER和PR信号的增加被肿瘤抑制因子WWOX 1减弱 但是这些蛋白质调节转录、细胞功能、生长和 肿瘤发生在很大程度上是未知的。为了了解这些蛋白质的作用机制及其 生理和病理相关性，我们假设癌蛋白YAP 1的共激活功能， 依赖于WBP-2，其中WBP-2：YAP 1复合物增强ER和PR反式激活功能 导致乳腺肿瘤发生。我们进一步假设WWOX 1作为肿瘤抑制因子， 物理上阻断这种复合物（WBP-2：YAP 1）的形成，导致其 共激活和致癌功能。这一假设将通过以下具体目标进行检验： 确定含WW-domain蛋白YAP 1和WWOX 1在ER和PR介导的基因中的作用 B）阐明WBP-2、YAP 1和WWOX 1调控ER和PR的机制 C）确定WBP-2、YAP 1和WWOX 1在乳腺肿瘤发生中的作用。

Project Summary/Abstract Estrogen receptor-¿ (ER) and progesterone receptor (PR) are ligand-induced transcription factors. Accessory proteins, termed coactivators modulate the transcriptional activation of these factors. It has been shown that coactivators enhance transcription of the target genes and play important roles in diverse pathological processes, such as cancers, inherited genetic diseases, metabolic disorders, and inflammation. Earlier work by our laboratory identified E6-associated protein (E6-AP) as a coactivator of steroid hormone receptors. In an attempt to identify E6-AP-interacting protein(s), we have cloned WW-domain binding protein-2 (WBP-2) and have shown that WBP-2 selectively coactivates the transactivation functions of ER and PR. WBP-2 is a novel polyproline rich (PPXY) motif containing protein. The PPXY motif of WBP-2 has been shown to be involved in transcriptional activation pathways. The PPXY motif interacts with WW-domain containing proteins and form PPXY motif and WW-domain (PPXY-WW) complex and mediates transcription stimulation. The PPXY-WW module has gained prominence in the last decade and many new roles of the PPXY-WW complex in the nucleus, cellular pathways, physiological and pathological processes are just emerging. WW-domains have been observed on several key regulatory proteins like yes associated protein (YAP1) and WW-domain- containing oxidoreductase (WWOX1). YAP1 has been shown to act as transcriptional coactivator for several transcription factors and has also been classified as an oncoprotein, whereas, WWOX1 has been identified as a tumor suppressor. Our preliminary data suggest that oncogenic YAP1 in conjunction with WBP-2 enhances ER and PR signaling. This increased in ER and PR signaling is attenuated by the tumor suppressor WWOX1 but the exact mechanism by which these proteins regulate transcription, cell function, growth and tumorigenesis is largely unknown. In order to understand the mechanism of action of these proteins and their physiological and pathological relevance, we hypothesize that the coactivation functions of oncoprotein YAP1 is dependent on WBP-2 where the WBP-2:YAP1 complex enhances ER and PR transactivation functions resulting in breast tumorigenesis. We further hypothesize that WWOX1 acts as a tumor suppressor by physically blocking the formation of this complex (WBP-2:YAP1) resulting in the attenuation of their coactivation and oncogenic functions. This hypothesis will be test by the following specific aims: A) To determine the role of WW-domain containing proteins, YAP1 and WWOX1 in ER and PR-mediated gene transcription; B) To decipher the mechanism by which WBP-2, YAP1 and WWOX1 regulate ER and PR transactivation functions; and C) To determine the role of WBP-2, YAP1 and WWOX1 in breast tumorigenesis.