Cellular and molecular mechanisms involved in the regulation of group IVA phospolipase A2

参与 IVA 族磷脂酶 A2 调节的细胞和分子机制

• 批准号: RGPIN-2015-04728
• 负责人: Flamand, Nicolas
• 金额: $ 2.19万
• 依托单位: Université Laval
• 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=650821
• 关键词: Cellular; molecular; mechanisms; involved; regulation

Arachidonic acid is fatty acid mainly found in animals. It plays critical roles in many processes, from fever to reproduction. It is so important that animals that can't make it, such as the cat, are obligatory carnivorous and then get the arachidonic acid from the meat they eat. Humans can however make it from vegetable oil containing linoleic acid. In our body, arachidonic acid is hidden within our cell walls. Special proteins named phospholipases A2 are responsible for providing arachidonic acid to our cells. Among the phospholipases A2 family, the cytosolic phospholipase A2 is very important, probably because it is found everywhere in our body. Thus, understanding how the cytosolic phospholipase A2 works is very helpful in order to understand the physiological mechanisms by which life itself is sustained. ***We reasonably understand how the cytosolic phospholipase A2 releases arachidonic acid. However, we do not really know how the cytosolic phospholipase A2 stops releasing arachidonic acid. This is very important because not enough or too much arachidonic acid can be lethal. Our research program aims at understanding how the cytosolic phospholipase A2 stops releasing to arachidonic acid. In this regard, we are proposing to define 2 ways by which the activity of cytosolic phospholipase A2 is turned down.***The first way implies a direct modification of the cytosolic phospholipase A2 by adding a phosphate group. This likely leads to a significant decrease in arachidonic acid release. The second way involves arachidonic acid itself, which might induce the cytosolic phospholipase A2 to stop releasing it. Such a retroactive inhibition has never been documented. We were able to engineer the cytosolic phospholipase A2 in a pure form and can therefore perform many tests on the latter. We thus anticipate to define, using biochemistry molecular biology techniques, two important stop signals by which the activity of the cytosolic phospholipase A2 is turned off.***The benefits are immense as 1) it will provide key aspects on how arachidonic acid is released and 2) it will train highly qualified personnel in the field of biochemistry and mass spectrometry of lipids, a research area that is poorly represented among the Canadian scientific community.***In conclusion, this project will provide important insights on the regulation of the cytosolic phospholipase A2, notably about its interaction with the membranes. It will also provide useful data for the understanding of lipid mediator biosynthesis and their role in physiology and might define arachidonic acid as a central regulator of cytosolic phospholipase A2 release.**

花生四烯酸是一种主要存在于动物体内的脂肪酸。它在许多过程中起着关键作用，从发烧到繁殖。这是如此重要，动物不能使它，如猫，是强制性的食肉，然后从他们吃的肉获得花生四烯酸。然而，人类可以从含有亚油酸的植物油中制造它。在我们的身体中，花生四烯酸隐藏在我们的细胞壁中。被称为磷脂酶A2的特殊蛋白质负责为我们的细胞提供花生四烯酸。在磷脂酶A2家族中，胞质磷脂酶A2非常重要，可能是因为它在我们体内无处不在。因此，了解胞质磷脂酶A2的工作原理对于理解维持生命的生理机制非常有帮助。* 我们合理地理解胞质磷脂酶A2如何释放花生四烯酸。然而，我们并不真正知道胞浆磷脂酶A2如何停止释放花生四烯酸。这是非常重要的，因为没有足够或太多的花生四烯酸可能是致命的。我们的研究计划旨在了解胞浆磷脂酶A2如何停止释放花生四烯酸。在这方面，我们建议定义两种降低胞浆磷脂酶A2活性的方式。*第一种方式意味着通过添加磷酸基团直接修饰胞质磷脂酶A2。这可能导致花生四烯酸释放的显著减少。第二种方式涉及花生四烯酸本身，花生四烯酸可能诱导胞浆磷脂酶A2停止释放磷脂酶A2。我们能够以纯的形式设计胞质磷脂酶A2，因此可以对后者进行许多测试。因此，我们期望使用生物化学分子生物学技术来定义两个重要的停止信号，通过这两个信号，胞质磷脂酶A2的活性被关闭。好处是巨大的，因为1）它将提供有关花生四烯酸如何释放的关键方面，2）它将培养脂质生物化学和质谱领域的高素质人员，这是一个在加拿大科学界代表性不强的研究领域。总之，该项目将提供重要的见解调节胞浆磷脂酶A2，特别是关于其与膜的相互作用。这也将为了解脂质介质的生物合成及其在生理学中的作用提供有用的数据，并可能将花生四烯酸定义为胞质磷脂酶A2释放的中心调节剂。