Regulation of Ceramide Synthase by Protein-Protein Interaction

标题：通过蛋白质-蛋白质相互作用调节神经酰胺合酶 摘要： 神经酰胺是所有鞘脂的骨架，神经酰胺脱氢酶（CerS）是关键酶 用于神经酰胺的从头生产。尽管CerS在神经酰胺生成中起着关键作用，但存在严重的 缺乏对这些酶如何调节的理解。这个项目的长期目标是揭示 并了解CerS酶如何调节的基本分子机制。使用 通过蛋白质组学方法，我们发现小的热休克蛋白Hsp 27与CerS 1特异性相互作用。 基于我们的初步数据，我们产生了新的假设，即Hsp 27是CerS 1的负调节因子 通过p38-MK2 MAPK介导的Hsp 27磷酸化可调节的直接相互作用的活性，和 Hsp 27的下调诱导CerS 1/C18：0-神经酰胺介导的细胞应答。为了验证这一 目的1：明确Hsp 27的生物化学意义 在鞘脂代谢和信号转导方面介导CerS 1在细胞中的调节。目标2：定义 Hsp 27介导CerS 1调节的生物学意义。目的3：确定热休克蛋白27- CerS 1蛋白-蛋白相互作用。总的来说，这些研究将确立Hsp 27作为一种内源性调节剂， 揭示了Hsp 27调控CerS 1和CerS 1/C18：0-神经酰胺调控CerS 1的新机制 线粒体自噬和癌细胞死亡。从这项研究中产生的知识将有助于设计机制为基础的 通过鉴定C18：0-神经酰胺作为关键介质的抗癌症和其它病理学的新疗法， 调节CerS 1活性的新方法。

Title: REGULATION OF CERAMIDE SYNTHASE BY PROTEIN-PROTEIN INTERACTION Abstract: Ceramides form the backbone of all sphingolipids, and ceramide synthases (CerS) are critical enzymes for de novo production of ceramides. In spite of the key role of CerS in ceramide generation, there is a serious deficiency in understanding how these enzymes are regulated. The long-term goal of this project is to uncover and understand the fundamental molecular mechanisms of how CerS enzymes are regulated. Using a proteomics approach, we discovered that the small heat shock protein Hsp27 interacts specifically with CerS1. Based on our preliminary data we generated the novel hypothesis that Hsp27 is a negative regulator of CerS1 activity via direct interaction that can be modulated by p38-MK2 MAPK mediated phosphorylation of Hsp27, and that down-regulation of Hsp27 induces CerS1/C18:0-ceramide mediated cellular responses. To test this hypothesis, we propose the following Specific Aims: Aim 1: Define the biochemical significance of Hsp27 mediated CerS1 regulation in cells with respect to sphingolipid metabolism and signal transduction. Aim 2: Define the biological significance of Hsp27 mediated CerS1 regulation. Aim 3: Determine the mechanism of Hsp27- CerS1 protein-protein interaction. Overall, these studies will establish Hsp27 as an endogenous modulator of CerS1 and uncover a novel mechanism of how Hsp27 regulates CerS1 and CerS1/C18:0-ceramide governed mitophagy and cancer cell death. The knowledge generated from this study will help design mechanism-based novel therapies against cancer and other pathologies in which C18:0-ceramide is the key mediator by identifying new methods to modulate CerS1 activity.