REGULATION OF METABOLISM IN INSECT FAT BODY

在昆虫中，脂肪体在能量代谢中起着重要作用。 它 是储存糖原和三酰甘油的主要场所 （TG）。 生理机制必须运作以积累能量储存， 无论是糖原或TG，在过量能量摄入期间，例如， 在幼虫发育期间，或在 需要，例如，逃跑或饿死。 显然，对这些问题的理解 机制在昆虫生物化学/生理学中具有根本重要性， 并可能提供有用的信息，为发展昆虫特异性 控制策略。 该项目的长期目标是表征信号 昆虫糖原和TG动员的转导系统 肥胖的身体。 在项目的初期阶段， 将是M.主要表现为 AKH在幼虫期的糖原分解作用， AKH在成人中的脂解作用。 这意味着我们可以学习 糖原分解或脂解取决于昆虫的生命阶段 直接取上游 从长远来看，我们计划使用的试剂和见解 从M. Sexta研究能量调节 在蚊子--埃及伊蚊的脂肪体中进行新陈代谢。 该提案的具体目标是： 激素敏感的脂肪酶，特别是，以确定机制 为了验证这一假设， 该酶激活脂解，因为该酶的磷酸化导致 从细胞质转移到脂肪滴;确定 脂肪体中甘油二酯合成途径， 脂肪分解的三酰甘油商店，并表征调节 为了确定海藻糖的合成是否受到调节， 糖原分解，特别是，为了检验果糖- 2，6-双磷酸盐通过抑制 糖酵解，从而将葡萄糖-1-磷酸分流成海藻糖 确定cAMP依赖性蛋白激酶在 调节糖原分解和脂肪分解;确定相对 钙离子和蛋白质磷酸化在活化中重要性 磷酸化酶激酶是激活糖原的关键酶 磷酸化酶和糖原分解。

In insects the fat body plays a fundamental role in energy metabolism. It is the principal site for storage of both glycogen and triacylglycerol (TG). Physiological mechanisms must operate to accumulate energy stores, either as glycogen or TG, during times of excess energy intake, e.g., during larval development, or to mobilize energy stores during times of need, e.g., flight or starvation. Clearly an understanding of these mechanisms is of fundamental importance in insect biochemistry/physiology, and may provide information useful for the development of insect-specific control strategies. The long-range goal of this project is to characterize the signal transduction systems involved in glycogen and TG mobilization in insect fat body. In the initial stages of the project the experimental insect will be larvae and adults of M. sexta which exhibit predominately a glycogenolytic effect of AKH in the larval stage and a predominately lipolytic effect of AKH in adults. This means we can study either glycogenolysis or lipolysis depending on which life stage of the insecxt is selected. In the long-range we plan to use the reagents and insights developed from studies on M. sexta to investigate regulation of energy metabolism in the fat body of the mosquito, Aedes aegypti. The specific aims of this proposal re: To characterize the fat body hormone sensitive lipase, and, in particular, to determine the mechanism of it phosphorylation and to test the hypothesis that phosphorylation of the enzyme activates lipolysis because phosphorylation of the enzyme leads to translocation from the cytoplasm to the fat droplet; To determine the pathway for diacylglycerol synthesis in fat body which is activated by lipolysis of the triacylglycerol stores, and to characterize regulation of the pathway; To determine if trehalose synthesis is regulated during glycogenolysis, and, in particular, to test the hypothesis that fructose- 2,6-bisphophate plays an important regulatory role by inhibiting glycolysis and thereby shunting glucose-1-phosphate into trehalose synthesis; To determine the role of the cAMP-dependent protein kinase in regulating glycogenolysis and lipolysis; To determine the relative importance of calcium ion and protein phosphorylation in activating phosphorylase kinase, which is the key enzyme in activating glycogen phosphorylase and, hence, glycogenolysis.