ORM Protein Regulation of Sphingolipid Biosynthesis in Yeast and Mammals

ORM 蛋白对酵母和哺乳动物鞘脂生物合成的调节

• 批准号: 8684517
• 负责人: TERESA M DUNN
• 金额: $ 23.34万
• 依托单位: HENRY M. JACKSON FDN FOR THE ADV MIL/MED
• 依托单位国家: 美国
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-04-10 至 2016-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8684517
• 关键词: Address; Affect; American; Anabolism; Animals; Asthma; Binding; Biochemical; Biological Assay; Cell physiology; Cells; Centers for Disease Control and Prevention (U.S.); Child; Childhood Asthma; Chronic Disease; Commit; Complex; Confocal Microscopy; Data; Disease; Dissociation; Endoplasmic Reticulum; Enzymes; Family; Fluorescence Resonance Energy Transfer; Functional disorder; Genes; Genetic Polymorphism; Goals; Homeostasis; Human; Hybrids; In Vitro; Incidence; Laboratories; Lead; Left; Link; Lipids; Lung diseases; Mammalian Cell; Mammals; Mass Spectrum Analysis; Measures; Mediating; Messenger RNA; Methods; N-terminal; National Health Interview Survey; Normal Cell; Pathogenesis; Phosphorylation; Physiological; Post-Translational Protein Processing; Proteins; RNA Interference; Reagent; Regulation; Repression; Role; Sphingolipids; Ubiquitin; Yeasts; base; in vivo; innovation; insight; member; overexpression; public health relevance; research study; response; serine palmitoyltransferase; tool

DESCRIPTION (provided by applicant): Asthma is one of the most common chronic diseases afflicting American children and the rate of incidence, currently 10%, has nearly doubled since 1980. Although the reason for this increase has not been determined, several genes have been implicated in the pathogenesis of this disorder. Among these is ORMDL3, a member of the ORM family of endoplasmic reticulum (ER) proteins that have recently emerged as key regulators of sphingolipid biosynthesis. The sphingolipids are a diverse family of lipids with crucialcellular functions and it is therefore not surprising that aberrant regulation of their synthesis and degradation has been associated with numerous disorders. Despite their importance, the mechanisms responsible for sphingolipid homeostasis are poorly understood. Therefore, the recent discovery that the ORM proteins exist in a complex ("SPOTS") with serine palmitoyltransferase (SPT), the committed enzyme of sphingolipid biosynthesis, is very significant. Studies in yeast suggest that regulation of SPT by the ORMs is controlled by phosphorylation of their N-terminal domains and redistribution of the SPOTS complex within the ER. The redistribution is consistent with the observation that while ORM regulation of in vivo SPT activity can be easily measured, in vitro SPT activity is unaffected by the ORMs. Mammalian ORMDLs also regulate in vivo SPT activity. However, they lack the N-terminal extensions found in their yeast counterparts, suggesting a different mechanism of regulation. Using a set of highly innovative reagents and methods developed in our laboratory to study the structural organization of both yeast and human SPT, we will resolve key outstanding questions regarding the mechanism of regulation of SPT by the ORMs. First, we will determine whether SPT activity is regulated by the oligomeric state and/or redistribution of the SPOTS complex within the ER in yeast and mammalian cells. Second, we will investigate the mechanism responsible for regulation of mammalian SPT by the ORMDLs, which lack the N-terminal regulatory domain found in their yeast counterparts. The data obtained from these exploratory studies will provide important new information about the regulation of sphingolipid biosynthesis in general, and lay the groundwork for studies in animals and humans that will elucidate the role of ORMDL3 in the pathophysiology of asthma.

描述（由申请人提供）：哮喘是困扰美国儿童的最常见慢性疾病之一，其发病率目前为 10%，自 1980 年以来几乎翻了一番。虽然这种增加的原因尚未确定，但有几个基因与这种疾病的发病机制有关。其中包括 ORMDL3，它是内质网 (ER) 蛋白 ORM 家族的成员，最近已成为鞘脂生物合成的关键调节因子。鞘脂是具有重要细胞功能的多样化脂质家族，因此其合成和降解的异常调节与许多疾病相关也就不足为奇了。尽管鞘脂稳态很重要，但人们对鞘脂稳态机制知之甚少。因此，最近发现ORM蛋白与鞘脂生物合成的关键酶丝氨酸棕榈酰转移酶(SPT)存在于复合物(“SPOTS”)中是非常重要的。酵母研究表明，ORM 对 SPT 的调节是通过其 N 末端结构域的磷酸化和 ER 内 SPOTS 复合物的重新分布来控制的。这种重新分布与观察结果一致，即虽然可以容易地测量ORM对体内SPT活性的调节，但体外SPT活性不受ORM的影响。哺乳动物 ORMDL 还调节体内 SPT 活性。然而，它们缺乏酵母对应物中发现的 N 末端延伸，这表明它们存在不同的调节机制。使用我们实验室开发的一套高度创新的试剂和方法来研究酵母和人类SPT的结构组织，我们将解决有关ORM调节SPT机制的关键悬而未决的问题。首先，我们将确定酵母和哺乳动物细胞中 SPT 活性是否受到 ER 内 SPOTS 复合物的寡聚状态和/或重新分布的调节。其次，我们将研究 ORMDL 调节哺乳动物 SPT 的机制，ORMDL 缺乏酵母对应物中的 N 端调节结构域。从这些探索性研究中获得的数据将提供有关鞘脂生物合成一般调节的重要新信息，并为动物和人类研究奠定基础，阐明 ORMDL3 在哮喘病理生理学中的作用。