State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, 100193, China.
Department of Biology, University of Firenze, 50019, Firenze, Italy.
Biol Rev Camb Philos Soc. 2018 Feb;93(1):184-200. doi: 10.1111/brv.12339. Epub 2017 May 7.
Odorant-binding proteins (OBPs) and chemosensory proteins (CSPs) are regarded as carriers of pheromones and odorants in insect chemoreception. These proteins are typically located in antennae, mouth organs and other chemosensory structures; however, members of both classes of proteins have been detected recently in other parts of the body and various functions have been proposed. The best studied of these non-sensory tasks is performed in pheromone glands, where OBPs and CSPs solubilise hydrophobic semiochemicals and assist their controlled release into the environment. In some cases the same proteins are expressed in antennae and pheromone glands, thus performing a dual role in receiving and broadcasting the same chemical message. Several reports have described OBPs and CSPs in reproductive organs. Some of these proteins are male specific and are transferred to females during mating. They likely carry semiochemicals with different proposed roles, from inhibiting other males from approaching mated females, to marking fertilized eggs, but further experimental evidence is still needed. Before being discovered in insects, the presence of binding proteins in pheromone glands and reproductive organs was widely reported in mammals, where vertebrate OBPs, structurally different from OBPs of insects and belonging to the lipocalin superfamily, are abundant in rodent urine, pig saliva and vaginal discharge of the hamster, as well as in the seminal fluid of rabbits. In at least four cases CSPs have been reported to promote development and regeneration: in embryo maturation in the honeybee, limb regeneration in the cockroach, ecdysis in larvae of fire ants and in promoting phase shift in locusts. Both OBPs and CSPs are also important in nutrition as solubilisers of lipids and other essential components of the diet. Particularly interesting is the affinity for carotenoids of CSPs abundantly secreted in the proboscis of moths and butterflies and the occurrence of the same (or very similar CSPs) in the eyes of the same insects. A role as a carrier of visual pigments for these proteins in insects parallels that of retinol-binding protein in vertebrates, a lipocalin structurally related to OBPs of vertebrates. Other functions of OBPs and CSPs include anti-inflammatory action in haematophagous insects, resistance to insecticides and eggshell formation. Such multiplicity of roles and the high success of both classes of proteins in being adapted to different situations is likely related to their stable scaffolding determining excellent stability to temperature, proteolysis and denaturing agents. The wide versatility of both OBPs and CSPs in nature has suggested several different uses for these proteins in biotechnological applications, from biosensors for odours to scavengers for pollutants and controlled releasers of chemicals in the environment.
气味结合蛋白（OBPs）和化学感受蛋白（CSPs）被认为是昆虫化学感受中信息素和气味的载体。这些蛋白通常位于触角、口器和其他化学感受结构中；然而，最近在身体的其他部位也检测到了这两类蛋白，并且提出了各种功能。其中研究最多的非感觉任务是在信息素腺中完成的，OBPs 和 CSPs 可溶解疏水性半化学物质，并协助它们受控释放到环境中。在某些情况下，相同的蛋白在触角和信息素腺中表达，从而在接收和广播相同的化学信息方面发挥双重作用。有几项报道描述了生殖器官中的 OBPs 和 CSPs。其中一些蛋白是雄性特异性的，在交配过程中传递给雌性。它们可能携带具有不同提议作用的半化学物质，从阻止其他雄性接近交配后的雌性，到标记受精卵，但仍需要进一步的实验证据。在昆虫中发现结合蛋白之前，在哺乳动物的信息素腺和生殖器官中广泛报道了结合蛋白的存在，在哺乳动物中，结构上不同于昆虫的脊椎动物 OBPs 属于亲脂素超家族，在啮齿动物尿液、猪唾液和仓鼠阴道分泌物以及兔子精液中大量存在。至少有四种情况报道 CSPs 促进了发育和再生：在蜜蜂的胚胎成熟、蟑螂的肢体再生、火蚁的蜕皮以及蝗虫的相位转变中。OBPs 和 CSPs 在营养方面也很重要，可作为脂质和饮食中其他必需成分的溶解剂。特别有趣的是，CSPs 对大量分泌在蛾和蝴蝶喙中的类胡萝卜素的亲和力，以及在同一昆虫的眼睛中出现相同（或非常相似的 CSPs）。这些蛋白在昆虫中作为视觉色素载体的作用类似于脊椎动物中的视黄醇结合蛋白，视黄醇结合蛋白在结构上与脊椎动物的 OBPs 有关。OBPs 和 CSPs 的其他功能包括在吸血昆虫中具有抗炎作用、对杀虫剂的抗性和蛋壳形成。这两类蛋白在不同情况下的高度适应性和多种功能可能与其稳定的支架结构有关，该支架结构确保了对温度、蛋白水解和变性剂的极好稳定性。OBPs 和 CSPs 在自然界中的广泛多功能性表明，这些蛋白在生物技术应用中有几种不同的用途，从气味生物传感器到污染物清除剂和环境中化学物质的受控释放剂。
