Mobilization of Triacylglycerol Stores in Insects

昆虫体内三酰甘油储存的动员

• 批准号: 6849339
• 负责人: Estela L. Arrese
• 金额: $ 18.61万
• 依托单位: OKLAHOMA STATE UNIVERSITY STILLWATER
• 依托单位国家: 美国
• 财政年份: 2002
• 资助国家: 美国
• 起止时间: 2002-02-01 至 2007-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6849339
• 关键词: Manduca; age difference; arthropod genetics; chemical kinetics; chemical structure function; diacylglycerols; enzyme model; enzyme substrate complex; hormone regulation /control mechanism; intermolecular interaction; intracellular transport; invertebrate hormone; larva; lipid metabolism; lipid transport; macromolecule; mature animal; model design /development; molecular cloning; protein kinase A; protein purification; radiotracer; stereochemistry; transport proteins; triacylglycerol lipase; triglycerides

DESCRIPTION: (provided by the applicant): Unlike vertebrates, where the stored fatty acids are mobilized as free fatty acids, a great number of insects, mobilizes fatty acids as an-1, 2-diacylglycerol (DG). The mobilization of TG stores requires the action of a TG-lipase, whose activity is hormonally regulated. The substrate of the lipase (TG) is found in large intracellular lipid droplets, which are constituted by a core of TG surrounded by a complex surface layer of phospholipids and proteins. On the other hand, the TG-lipase localizes in the cytosol of lipolytically unstimulated fat body cells. Lipolysis involves the interaction of the lipase with the surface of the lipid droplet. It is known that activation of lipolysis promotes both an increase of intracellular calcium concentration and activation of amp-dependent protein kinase (A-kinase) but the basic mechanisms involved in how phosphorylation-dephosphorylation reactions modulate the rate of lipolysis is unknown. Moreover, little is known about the relevance and nature of the structural and compositional changes that affect the lipid droplet when lipolysis is hormonally activated. These changes must ultimately affect the interaction of the lipase with the lipid substrate and the concomitant activation of lipolysis. DG moves from the lipid droplet to the plasma membrane by an uncharacterized mechanism. It appears that after the conversion of TG into DG on the surface of the lipid droplets, DG would be transferred to a cytosolic carrier, which in turn would target the delivery of DG across the plasma membrane. The overall goals of this project are to establish the mechanisms regulating lipolysis by determining the factors that promotes the interaction between TG-lipase and its substrate, the lipid droplet and to define the mechanism of intracellular transport of DG. Clearly the elucidation of these mechanisms is of fundamental importance in insect biochemistry and physiology. These studies will provide comprehensive information on the lipolytic process in insects and this knowledge could also contribute to the broad field of lipid metabolism and transport in vertebrates.

描述：（由申请人提供）：与存储的脊椎动物不同 脂肪酸被动员为游离脂肪酸，大量昆虫， 动员脂肪酸为AN-1、2-二酰基甘油（DG）。 TG的动员 商店需要TG-脂肪酶的作用，其活性在荷尔蒙上 受监管。脂肪酶（TG）的底物在大细胞内发现 脂质液滴，由TG的核心构成，被复合物包围 磷脂和蛋白质的表面层。另一方面，TG脂肪酶 定位在脂肪解析未刺激的脂肪体细胞的胞质中。 脂解涉及脂肪酶与脂质表面的相互作用 液滴。众所周知，脂解的激活促进了 细胞内钙浓度和AMP依赖性蛋白的激活 激酶（A-激酶），但是如何 磷酸化 - 脱磷酸反应调节脂解的速率为 未知。而且，对有关的相关性和性质知之甚少 结构和成分变化，影响脂质液滴时 脂解会激活脂肪。这些变化必须最终影响 脂肪酶与脂质底物的相互作用和伴随的 脂解的激活。 DG从脂质液滴移到质膜 通过未表征的机制。看来TG转换后 进入脂质液滴表面的DG，将DG转移到A 胞质载体，这反过来将针对DG的递送 质膜。该项目的总体目标是建立 通过确定促进的因素来调节脂解的机制 TG-脂肪酶及其底物，脂质液滴和到TO之间的相互作用 定义DG细胞内转运的机制。显然阐明 这些机制在昆虫生物化学和 生理。这些研究将提供有关 昆虫中的脂解过程，这种知识也可能有助于 脂质代谢和脊椎动物的运输的广泛领域。