Hariton-Shalev Aliza, Shalev Moran, Adir Noam, Belausov Edurad, Altstein Miriam
Department of Entomology, The Volcani Center, Bet Dagan 50250, Israel.
Biochim Biophys Acta. 2013 Nov;1830(11):5036-48. doi: 10.1016/j.bbagen.2013.06.041. Epub 2013 Jul 10.
The pyrokinin/pheromone biosynthesis-activating neuropeptide (PK/PBAN) plays a major role in regulating a wide range of physiological processes in insects. The ubiquitous and multifunctional nature of the PK/PBAN peptide family raises many questions regarding the mechanisms by which these neuropeptides elicit their effects and the nature of the receptors that mediate their functions.
A sex pheromone gland receptor of the PK/PBAN family from Heliothis peltigera female moth and a Spodoptera littoralis larval receptor were cloned and stably expressed, and their structural models, electrostatic potentials and cellular functional properties were evaluated.
Homology modeling indicated highly conserved amino-acid residues in appropriate structural positions as experimentally shown for class A G-protein coupled receptors. Structural differences could be proposed and electrostatic potentials of the two receptor models revealed net charge differences. Calcium mobilization assays demonstrated that both receptors were fully functional and could initiate extracellular calcium influx to start PK/PBAN signal transduction. Evaluation of the signaling response of both receptors to PBAN and diapause hormone (DH) revealed a highly sensitive, though differential response. Both receptors responded to PBAN whereas only Spl-PK/PBAN-R exhibited a high response toward DH.
The structural, electrostatic and cellular functional differences indicate that different PK/PBAN in vivo functions may be mediated by different PK/PBAN receptors and elicited by different peptide(s).
The results advance our understanding of the mode of action of the PK/PBAN family, and might help in exploring novel high-affinity receptor-specific antagonists that can serve as a basis for the development of new families of insect-control agents.
焦激肽/信息素生物合成激活神经肽（PK/PBAN）在调节昆虫广泛的生理过程中起主要作用。PK/PBAN肽家族的普遍存在和多功能性质引发了许多关于这些神经肽发挥作用的机制以及介导其功能的受体性质的问题。
克隆并稳定表达了棉铃虫雌蛾PK/PBAN家族的一种性信息素腺受体和一种斜纹夜蛾幼虫受体，并评估了它们的结构模型、静电势和细胞功能特性。
同源建模表明，在适当的结构位置存在高度保守的氨基酸残基，正如A类G蛋白偶联受体的实验所示。可以提出结构差异，并且两种受体模型的静电势显示出净电荷差异。钙动员试验表明，两种受体均功能完全，可以启动细胞外钙内流以开始PK/PBAN信号转导。对两种受体对PBAN和滞育激素（DH）的信号反应评估显示出高度敏感但不同的反应。两种受体均对PBAN有反应，而只有Spl-PK/PBAN-R对DH表现出高反应。
结构、静电和细胞功能差异表明，不同的PK/PBAN体内功能可能由不同的PK/PBAN受体介导，并由不同的肽引发。
这些结果推进了我们对PK/PBAN家族作用模式的理解，并可能有助于探索新型高亲和力受体特异性拮抗剂，这些拮抗剂可作为开发新型昆虫控制剂家族的基础。
