Regulation of pten tumor suppressive functions by C-tail phosphorylation.

项目总结/摘要 Pten是一种重要的肿瘤抑制因子，其肿瘤保护能力对pten水平的改变非常敏感。 表达或活动。这一性质导致了推测，控制Pten表达的机制， 能力、构象、同型和异型蛋白质相互作用、定位或催化活性，包括后 翻译修饰是人类癌症中失调的突出靶标。然而，这一概念 没有在生物体水平上进行严格的测试，主要是因为在小鼠中操作Pten的困难， 它在胚胎发生中的重要作用。我们的长期目标是通过使用鼠标来缩小这一知识差距 特定Pten结构域或调控机制失活的模型，并将信息应用于 获得了开发创新策略，用于治疗Pten改变的人类癌症。作为下一个 在追求这一目标的过程中，我们的目标是在生理水平上了解磷光体- C-尾区的化状态调节Pten。基于广泛的初步研究，我们假设， 单个C-尾丝氨酸/苏氨酸残基差异性地调节稳定性、定位、相互作用组和/或 体内Pten的磷酸酶活性，从而影响其在Akt依赖性肿瘤细胞中的肿瘤抑制功能。 独立的时尚。我们建议通过追求两个具体目标来检验这一假设。第一个目标，我们 将全面检查组织和培养的细胞，从一组核心的八个nonphosphorylatable和磷酸化， 拟肽C-尾突变小鼠中Pten生物学特性和功能的变化。第二个目标，我们 将监测这些相同的小鼠品系以及野生型、Pten亚纯型和Pten+/-小鼠的队列， 自发性肿瘤的发展，重点是前列腺和乳腺病变。另外我们 将对这些菌株的肿瘤前和肿瘤组织进行Pten改变的比较分析 性能和功能。通过完成这些目标，我们期望深入了解这些C尾的性质 突变体在生理学相关环境中关于蛋白质稳定性、定位、催化活性和 结合伙伴，并将这些发现与有关生物和肿瘤抑制的信息结合起来， 这些突变体失去、保留或获得的功能。这一创新举措的预期总体影响 建议是，它将从根本上推进我们对正常和肿瘤功能的机械理解- 在人类癌症中第二个最常突变的肿瘤抑制基因。这些知识将被... 在癌症生物学领域的发展，提高我们对正常人Akt信号通路的理解， 生理学和癌症，并为开发新的治疗策略奠定基础， Pten改变的癌症患者的临床结果。

PROJECT SUMMARY/ABSTRACT Pten is a prominent tumor suppressor whose tumor protective ability is exquisitely sensitive to alterations in level of expression or activity. This property has led to speculation that mechanisms controlling Pten expression, sta- bility, conformation, homo- and heterotypic protein interactions, localization, or catalytic activity, including post- translational modifications, are prominent targets for deregulation in human cancer. However, this concept has not been critically tested at the organismal level, mainly because of difficulty in manipulating Pten in mice due to its essential role in embryogenesis. Our long-term objective is to close this knowledge gap by the use of mouse models in which specific Pten domains or regulatory mechanisms are inactivated and to apply the information gained to develop innovative strategies for the treatment of human cancers with Pten alterations. As the next step in the pursuit of this goal, our objective here is to understand, at the physiological level, how the phosphor- ylation status of the C-tail region regulates Pten. Based on extensive preliminary studies, we hypothesize that individual C-tail serine/threonine residues differentially regulate the stability, localization, interactome and/or phosphatase activity of Pten in vivo, thereby impacting its tumor suppressive functions in both Akt-dependent and -independent fashions. We propose to test this hypothesis by pursuing two specific aims. In the first aim, we will comprehensively examine tissues and cultured cells from a core set of eight nonphosphorylatable and phos- phomimetic C-tail mutant mice for changes in Pten biological properties and functions. In the second aim, we will monitor these same mouse strains alongside cohorts of wildtype, Pten hypomorphic and Pten+/– mice for the development of spontaneous tumors, with emphasis on prostate and mammary gland lesions. Additionally, we will conduct a comparative analysis of pre-tumorous and tumorous tissues of these strains for alterations in Pten properties and functions. By completing these aims, we expect to gain insight into the properties of these C-tail mutants in physiologically relevant settings with regards to protein stability, localization, catalytic activity and binding partners, and to integrate these findings with information about the biological and tumor suppressive functions that these mutants have lost, preserved, or gained. The expected overall impact of this innovative proposal is that it will fundamentally advance our mechanistic understanding of the normal and neoplastic func- tions of the second most frequently mutated tumor suppressor gene in human cancer. This knowledge will con- ceptually advance the cancer biology field, improve our understanding of the Akt signaling pathway in normal physiology and cancer, and lay the foundation for the development of new therapeutic strategies that will improve the clinical outcome of cancer patients with alterations in Pten.