Adaptor protein function in breast cancer

项目摘要 本提案的总体目标是确定胰岛素受体底物2（IRS 2） 促进侵袭和在乳腺癌中的作用。IRS 2是一种细胞质衔接蛋白，是一种关键的信号转导蛋白。 胰岛素（IR）和胰岛素样生长因子-1（IGF 1 R）受体的效应子，两者均涉及 在乳腺癌中。缺乏Irs 2的小鼠乳腺肿瘤的转移能力显著降低 Irs 2表达升高的肿瘤具有增强的肿瘤生长和转移潜力。工作从 申请人的实验室已经确定IRS 2促进侵袭，这是转移性肿瘤扩散的早期步骤。 细胞到次级器官。IRS 2促进侵袭的重要性通过申请人最近的研究而得到加强。 发现IRS 2在多形性浸润性小叶癌（PILC）中反复突变， 转移性乳腺癌亚型重要的是，IRS 2整合上游信号以 介导其功能结果仍然未知。确定IRS 2如何调节入侵需要一个 了解它的结构，以及这种结构如何决定功能。申请人的初步资料 确定IRS 2促进侵袭的能力依赖于上游IGF 1 R/IR活化， 募集和激活PI 3 K。此外，他们在IRS 2 C-末端鉴定了一个174个氨基酸的区域， 这是入侵所必需的。重要的是，该区域不是IRS 2依赖性调节 葡萄糖摄取，揭示了IRS 2的这两种功能是独立调节的。基本互动 可能发生在这个区域内，因为它以显性负方式抑制入侵。探讨 IRS 2的结构被上游刺激物动态改变的假说， 促进必需的下游信号传导效应物的结合，申请人将：1）定义以下的结构基础： IRS 2介导的侵袭和信号传导。IRS 2中的特定序列参与 改变蛋白质构象和信号以促进入侵的动态分子内相互作用将是 2）研究IRS 2相互作用伙伴及其在促进入侵中的作用。的假设 IRS 2内的分子内相互作用导致“无序结构域”环的形成， 信号转导子复合物介导的功能结果，这些结合蛋白之一是丝氨酸 苏氨酸激酶BMP 2K将被检测; 3）确定IRS 2依赖性侵袭在乳腺癌中的作用 体内进展。选择性靶向IRS 2依赖性侵袭的假设将揭示一个重要的 将检查这种特定功能在乳腺癌进展中的作用。IRS 2突变的贡献 PILC的进展也将被检查。

Project Summary The overall goal of this proposal is to determine the mechanism by which Insulin Receptor Substrate 2 (IRS2) promotes invasion and its role in breast cancer. IRS2 is a cytoplasmic adaptor protein that is a key signaling effector of the insulin (IR) and insulin-like growth factor-1 (IGF1R) receptors, both of which have been implicated in breast cancer. Mouse mammary tumors that lack Irs2 are significantly diminished in their ability to metastasize and tumors with elevated Irs2 expression have enhanced tumor growth and metastatic potential. Work from the applicant’s lab has established that IRS2 promotes invasion, an early step in the dissemination of metastatic cells to secondary organs. The significance of IRS2 promoting invasion is heightened by the applicant’s recent discovery that IRS2 is recurrently mutated in pleomorphic invasive lobular carcinoma (PILC), an aggressive, metastatic breast cancer subtype. Importantly, the mechanism by which IRS2 integrates upstream signals to mediate its functional outcomes remains unknown. Determining how IRS2 regulates invasion requires an understanding of its structure, and how this structure determines function. The applicant’s preliminary data establish that the ability of IRS2 to promote invasion is dependent upon upstream IGF1R/IR activation and the recruitment and activation of PI3K. In addition, they identified a 174-amino acid region within the IRS2 C-terminal tail that is required for invasion. Importantly, this region is not required for the IRS2-dependent regulation of glucose uptake, revealing that these two functions of IRS2 are independently regulated. Essential interactions likely occur within this region given that it acts in a dominant negative manner to inhibit invasion. To investigate the hypothesis that the structure of IRS2 is dynamically altered by upstream stimuli that promote invasion to facilitate binding of essential downstream signaling effectors the applicant will: 1) Define the structural basis for IRS2-mediated invasion and signaling. The hypothesis that specific sequences within IRS2 participate in dynamic intramolecular interactions that alter protein conformation and signaling to promote invasion will be examined; 2) Investigate IRS2 interacting partners and their role in promoting invasion. The hypothesis that intramolecular interactions within IRS2 lead to the formation of “disordered domain” loops that assemble distinct signaling sub-complexes to mediate functional outcomes, and that one of these binding proteins is the serine threonine kinase BMP2K, will be examined; 3) Establish the role of IRS2-dependent invasion in breast cancer progression in vivo. The hypothesis that selective targeting of IRS2-dependent invasion will reveal an essential role for this specific function in breast cancer progression will be examined. The contribution of IRS2 mutations to PILC progression will also be examined.