Mobilization of Triacylglycerol Stores in Insects

描述：（申请人提供）：与脊椎动物不同， 脂肪酸以游离脂肪酸的形式被动员，大量的昆虫， 将脂肪酸作为α-1，2-二酰基甘油（DG）进行活化。TG的动员 储存需要TG-脂肪酶的作用，其活性与蛋白质的性质有关。 监管.脂肪酶（TG）的底物存在于大的细胞内， 脂滴，其由复合物包围的TG核心构成 磷脂和蛋白质的表面层。另一方面，TG-脂肪酶 定位于未受脂解刺激的脂肪体细胞的胞质溶胶中。 脂解涉及脂肪酶与脂质表面的相互作用 液滴。已知脂解的激活促进了脂肪酸的增加， 细胞内钙离子浓度与AMP依赖蛋白激活 激酶（A-激酶），但如何参与的基本机制 磷酸化-去磷酸化反应调节脂解的速率， 未知此外，人们对《公约》的相关性和性质知之甚少， 结构和组成的变化，影响脂滴时， 脂肪分解被尿道激活。这些变化最终将影响 脂肪酶与脂质底物的相互作用以及伴随的 脂解的激活。DG从脂滴向质膜移动 被一种未知的机制所控制看来，在转换TG之后， 当脂质滴表面的DG转化为DG时，DG将被转移到 细胞溶质载体，这反过来又将靶向DG的递送， 质膜该项目的总体目标是建立 通过确定促进脂肪分解的因子来调节脂肪分解的机制 TG-脂肪酶与其底物，脂滴和 阐明DG的胞内转运机制。很明显， 这些机制在昆虫生物化学中具有根本的重要性， physiology.这些研究将提供全面的信息， 昆虫的脂肪分解过程，这一知识也有助于 脊椎动物脂质代谢和转运的广阔领域。

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.