P13K/AKT crosstalk with ER-signaling and cell survival

I这项研究的主要长期目标是了解AKT信号与 雌激素受体(ER)在控制细胞存活和抗雌激素抵抗的发展中发挥重要作用。我们 假设AKT通路作用于靶向并磷酸化p160辅活化子GRIP和ER 调节辅酶A募集、受体激活和基因表达的蛋白质。我们进一步 假设AKT和雌激素信号在ER-CoA转录水平的融合在 细胞存活的调节及对激素选择性雌激素受体调节剂(SERM)活性的影响 依赖细胞系统，如乳腺癌。提出具体目标是：1)确定 通过检测ER-AF2的特异性靶向、磷酸化和激活来研究AKT-ER串扰的机制 和/或AKT的P160 CoA握力，以及2)通过检查 AKT-ER-CoA对内源性雌激素反应基因调控及SERM活性改变的影响 和基因表达，以及长期细胞存活。具体目标#1，确定AKT靶向和 ER-AF2的磷酸化是串扰的一种机制。我们建议确定ER-AF2靶向 通过AKT的直接磷酸化和特定的磷酸化位点在AKT-ER串扰中的作用发生。 特定目的#2，暗示AKT调节p160辅活化子(GRIP)磷酸化是一种 雌激素受体的激活和募集。研究将确定AKT是否磷酸化并激活 通过特异性靶向GRIP-NRID(核受体相互作用域)或GRIP-AD2(激活 结构域-2)作为AKT调节GRIP调控ER转录的机制。具体目标#3，以 确定AKT介导的内质网依赖细胞调节中GRIP磷酸化/功能的需求 存活率、基因表达和SERM活性。在这个目标中，我们将确定特定的AKT诱导的作用 ER-CoA募集/激活在细胞生存基因表达调控中的作用及丹参酮的影响 AKT-ER-CoA关于SERM活动的相声。这些研究还将确定是否存在 AKT-ER或GRIP自上而下的磷酸化在AKT-ER介导的细胞存活调节中起关键作用。它是 预计作为一个整体，这项提案将建立PI3K-AKT级联所使用的机制，以 ER和增强活性所需的ER转录复合体的后续成分 路径。这种串扰和所确定的机制将被用来建立 Dathway在细胞存活和改变SERM活性方面，

I The primary long-term objective of this research is to understand the role of AKT-signaling cross-talk with the estrogen receptor (ER) in the control of cell survival and in the development of anti-estrogen resistance. We hypothesize that the AKT pathway functions to target and phosphorylate the p160 coactivator GRIP and ER proteins leading to regulation of CoA-recruitment, receptor-activation and gene expression. We further hypothesize that convergence of the AKT and estrogen signaling at the ER-CoA-transcriptional level is critical in the regulation of cell survival and influences selective estrogen receptor modulator (SERM) activity in hormone dependent cell systems such as breast carcinoma. The Specific Aims are proposed to 1) Determine the mechanisms of AKT-ER cross-talk by examining specific targeting, phosphorylation and activation of ER-AF2 and/or the p160 CoA GRIP by AKT and 2) Determine the physiological relevance of this cross-talk by examining effects of AKT-ER-CoA on the regulation of endogenous estrogen-responsive genes, alteration of SERM-activity and gene expression, and long-term cell survival. Specific Aim #1, To determine the role of AKT targeting and phosphorylation of ER-AF2 as a mechanism for cross-talk. We propose to determine if the ER-AF2 targeting occurs through direct phosphorylation by AKT and the role of specific phosphorylation sites in AKT-ER cross-talk. Specific Aim #2, To implicate AKT regulation of p160 coactivator-(GRIP) phosphorylation as a mechanism for activation of and recruitment to estrogen receptors. Studies will determine if AKT phosphorylates and activates GRIP though specific targeting of the GRIP-NRID (nuclear receptor interaction domain) or GRIP-AD2 (activation domain-2) as mechanisms for AKT regulation of GRIP in control of ER transcription. Specific Aim #3, To determine the requirement for GRIP phosphorylation/function in AKT-mediated regulation of ER-dependent cell survival, gene expression and SERM activity. In this aim we will determine the role for specific AKT induced ER-CoA recruitment/activation in the regulation of cell survival gene expression (Bcl-2) and the influence of AKT-ER-CoA cross-talk on SERM activity. These studies will also determine if the mechanisms for AKT-phosphorylation of ER or GRIP from above are critical in the AKT-ER mediated regulation of cell survival. It is expected as a whole that this proposal will establish the mechanisms used by the PI3K-AKT cascade to target the ER and the subsequent components of the ER transcription complex required for potentiation of activity by this pathway. This cross-talk and the mechanisms identified will be used to establish the biological relevancy of the Dathway in terms of cell survival and altered SERM activity,