Molecular Developmental Physiology and Signal Transduction, KU Leuven, Naamsestraat 59, P.O. Box 02465, B-3000 Leuven, Belgium.
Department of Biological Sciences, University of Cape Town, Private Bag, Rondebosch ZA-7700, South Africa.
Int J Mol Sci. 2018 Feb 11;19(2):542. doi: 10.3390/ijms19020542.
Adipokinetic hormone (AKH) is a highly researched insect neuropeptide that induces the mobilization of carbohydrates and lipids from the fat body at times of high physical activity, such as flight and locomotion. As a naturally occurring ligand, AKH has undergone quite a number of amino acid changes throughout evolution, and in some insect species multiple AKHs are present. AKH acts by binding to a rhodopsin-like G protein-coupled receptor, which is related to the vertebrate gonadotropin-releasing hormone receptors. In the current study, we have cloned AKH receptors (AKHRs) from seven different species, covering a wide phylogenetic range of insect orders: the fruit fly, , and the yellow fever mosquito, (Diptera) the red flour beetle, , and the large pine weevil, (Coleoptera); the honeybee, (Hymenoptera); the pea aphid, (Hemiptera); and the desert locust, (Orthoptera). The agonistic activity of different insect AKHs, including the respective endogenous AKHs, at these receptors was tested with a bioluminescence-based assay in Chinese hamster ovary cells. All receptors were activated by their endogenous ligand in the nanomolar range. Based on our data, we can refute the previously formulated hypothesis that a functional AKH signaling system is absent in the beneficial species, . Furthermore, our data also suggest that some of the investigated AKH receptors, such as the mosquito AKHR, are more selective for the endogenous (conspecific) ligand, while others, such as the locust AKHR, are more promiscuous and can be activated by AKHs from many other insects. This information will be of high importance when further analyzing the potential use of AKHRs as targets for developing novel pest control agents.
脂肪动激素 (AKH) 是一种经过深入研究的昆虫神经肽，可在高体力活动（如飞行和运动）时从脂肪体中动员碳水化合物和脂肪。作为一种天然存在的配体，AKH 在进化过程中经历了相当多的氨基酸变化，并且在一些昆虫物种中存在多种 AKH。AKH 通过与一种类似视紫红质的 G 蛋白偶联受体结合而起作用，该受体与脊椎动物促性腺激素释放激素受体相关。在当前的研究中，我们从七个不同的物种中克隆了 AKH 受体 (AKHR)，涵盖了昆虫目广泛的系统发育范围：果蝇、蜜蜂、黄热病蚊子、红面粉甲虫、大松树象鼻虫、豌豆蚜虫和沙漠蝗虫。用基于生物发光的测定法在中国仓鼠卵巢细胞中测试了不同昆虫 AKH（包括各自的内源性 AKH）在这些受体上的激动活性。所有受体都以内源性配体在纳摩尔范围内被激活。根据我们的数据，我们可以反驳先前提出的假说，即功能性 AKH 信号系统在有益物种中不存在。此外，我们的数据还表明，一些研究中的 AKH 受体，如蚊子 AKHR，对内源性（同种）配体更具选择性，而其他受体，如蝗虫 AKHR，则更具混杂性，可以被来自许多其他昆虫的 AKH 激活。当进一步分析 AKHR 作为开发新型害虫控制剂的靶标时，这些信息将非常重要。
