Molecular Properties of Diacylglycerol Kinase Epsilon

二酰甘油激酶 Epsilon 的分子特性

基本信息

批准号：
RGPIN-2018-05585
负责人：
Epand, Richard
金额：
$ 3.06万
依托单位：
McMaster University
依托单位国家：
加拿大
项目类别：
Discovery Grants Program - Individual
财政年份：
2018
资助国家：
加拿大
起止时间：
2018-01-01 至 2019-12-31
项目状态：
已结题

来源：
https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=650245
关键词：
Molecular Properties Diacylglycerol Kinase Epsilon

项目摘要

The proposal is focused on a unique member of the family of mammalian diacylglycerol kinases, i.e. DGKε. DGKε plays a key role in signal transduction and lipid synthesis. It is the only known member of this group that appears to have specificity for one particular species of substrate, i.e. 1-stearoyl-2-arachidonoyl glycerol. This is the same acyl chain composition as is found in lipid intermediates of the phosphatidylinositol (PI) cycle, the sole pathway for the synthesis of PI and its phosporylated products that play a major role in metabolic regulation and cancer. Interconversion of these phosphorylated forms of PI is highly dependent on the nature of the acyl chains. DGKε contributes to the specific acyl chain composition of several lipids involved in cell signaling. The product of the reaction catalyzed by DGKε, phosphatidic acid, is also an important signaling agent as well as being a precursor for several other lipids. We have successfully purified catalytically active DGKε. This provides an opportunity to understand the molecular structure of this protein. It would be the first mammalian DGK isoform to have its structure determined and would provide a model for the analysis of other isoforms that have some homologous segments and for understanding the functioning of this important family of signaling proteins. We will also study how this protein interacts with membranes and with its substrate. It will be an important example of a peripheral membrane protein that interacts with lipid segments buried in the membrane. In cells DGKε functions when bound to a bilayer membrane. Before our success in purifying this enzyme, all activity studies were done in assays using detergent micelles. However, we are now able to use the purified enzyme to assay the activity in liposomes made of bilayer membranes. We found a marked difference between the micellar-based and the liposome-based assays and a dependence of both the activity and specificity on the chemical and physical properties of the lipids used to make the liposomes. This will enable us to gain an understanding of how the functioning of DGKε is dependent on the nature of the membrane to which it is bound. This research program will determine how peripheral membrane proteins can bind to membranes and recognize lipid substrates. The example of DGKε is of particular importance because of its involvement in determining the acyl chain composition of PI. There is currently no structural information on this protein and no reported studies of its activity on liposomes. Our work will provide important novel structural and functional information. It will contribute to our general understanding of the mechanism of acyl chain recognition by interfacial enzymes and in particular as applied to DGKε. This information will provide a more accurate description of an aspect of the regulation of biological systems that eventually will be used for their control.

该提议集中在符号d脂质合成中的关键作用。 PI是在代谢调节中起主要作用的PI和Phospory的产品。 DGKKKε为该蛋白质的分子结构提供了一个机会，它将为分析同源段的其他同工型分析和理解。这将是埋在膜上的脂质段的重要例子。在基于双层膜的脂质体中与该研究的膜结合的膜目前，蛋白质的结构信息和脂质体的活性的研究是重要的。用于控制。