Characterization of the Sch9 -Longevity Pathway in Yeast

描述(申请人提供)：模式生物，如酿酒酵母，已被证明在阐明调节寿命的基因和代谢物方面是有效的，这一知识构成了理解人类衰老和长寿的基础。这些研究已经确定Akt/PKB蛋白激酶是衰老的保守调节因子。然而，目前还不完全清楚它们是如何工作的。我们研究的一个重点是酿酒酵母Sch9蛋白激酶，它是一种AKT同源物，调节着时序寿命(CLS)。从体外研究中，我们确定鞘磷脂长链碱基(LCBs)和Pkh1是Sch9的第一个上游调节因子。此外，我们还鉴定了第一批参与翻译启动和核糖体生物发生的Sch9底物Rli1，以及防止氧化应激的烷基氢过氧化氢还原酶Ahp1。我们将在这些新结果的基础上，确定Sch9对Rli1和Ahp1的磷酸化是否在CLS中发挥作用。我们还将在体内确定LCB和Pkh1是否在时间老化过程中上游调节Sch9。虽然我们已经成功地鉴定了Sch9底物，但很可能还有其他底物，我们建议通过经典的生化策略、较新的自动化但互补的策略和遗传筛选策略来寻找新的底物。总之，这些研究的结果将提供对Akt(Sch9)活性如何在酵母中调节以及它如何通过下游底物调节CLS的迫切需要的机械理解。这些知识将有助于为理解人类衰老和长寿提供分子基础。与公共健康相关：拟议的研究将确定Sch9蛋白激酶，一种哺乳动物Akts/PKB的功能同源物，如何调节酿酒酵母中面包酵母的时间跨度。含有Akt/PKB类蛋白激酶的信号转导通路在调节衰老和寿命方面起着重要作用，这些通路从酵母到哺乳动物都是保守的。因此，从这些研究中获得的信息应该为理解人类的衰老和寿命是如何调节的提供了一个更机械的基础。

DESCRIPTION (provided by applicant): Model organisms, such as Saccharomyces cerevisiae, have proven effective in elucidating genes and metabolites that modulate life span and this knowledge forms a basis for understanding human aging and longevity. These studies have identified the Akt/PKB protein kinases as conserved regulators of aging. However, it is not entirely clear how they work. One focus of our research is the S. cerevisiae Sch9 protein kinase, an AKT homolog that regulates chronological life span (CLS). From in vitro studies we identified sphingolipid long chain bases (LCBs) and Pkh1, a homolog of human phosphoinositide-dependent protein kinase 1 (PDK1), as the first upstream regulator of Sch9. In addition, we identified the first Sch9 substrates, Rli1, involved in translation initiation and ribosome biogenesis, and Ahp1, an alkyl hydroperoxide reductase that protects against oxidative stress. We will build upon these novel results and determine if phosphorylation of Rli1 and Ahp1 by Sch9 plays a role in CLS. We will also determine in vivo if LCBs and Pkh1 act upstream to regulate Sch9 during chronological aging. Although we have successfully identified Sch9 substrates, there are likely to be others and we propose to search for new substrates by classical biochemical strategies, newer automated but complementary strategies, and a genetic screening strategy. In summary, the results of these studies will provide the much needed mechanistic understanding of how Akt (Sch9) activity is regulated in yeast and how it regulates CLS through downstream substrates. This knowledge will help to provide a molecular basis for understanding human aging and longevity. PUBLIC HEALTH RELEVANCE: The proposed research will determine how the Sch9 protein kinase, a functional homolog of mammalian Akts/PKBs, regulates chronological life span in the Baker's yeast Saccharomyces cerevisiae. Signal transduction pathways that contain Akt/PKB type protein kinases play important roles in regulating aging and life span, and these pathways have been conserved from yeast to mammals. Thus, information gained from these studies should provide a more mechanistic basis for understanding how aging and life span are regulated in humans.