Eat-2-ing away: acetylcholine receptor binding subunits lacking vicinal cysteines, a new pharmacophore for mitigation of plant parasitic infection.

控制昆虫和线虫移动的作用于神经肌肉传输的化学物质提供了成功的害虫管理。这种方法正在开发中的一个重要标准是选择性毒性，这使得治疗可以作为有效的虫害控制，而对无害生物的有害影响有限。传统上，这是通过定义在门和种之间选择性地发现的受体类别来解决的。我们最近在胆碱能传递中建立了一种组织选择性敏感性，这种敏感性在药理学上区分线虫的运动和取食(Gonzalez，J Biol Chem提交)。这种差异是由于在这些神经肌肉连接处支持胆碱能传递的主要乙酰胆碱受体的不同性质。咽部的传输依赖于一种未被研究的兴奋性烟碱型乙酰胆碱受体，称为EAT-2。这种受体是由内源性激动剂乙酰胆碱激活的一类新兴的同源寡聚受体。然而，EAT-2在烟碱受体中是独一无二的，因为在激动剂结合位点的高度进化保守的环C中缺乏标志性的邻近半胱氨酸。以前人们认为，这种邻近的半胱氨酸对同种和异种寡聚受体上的乙酰胆碱受体的激活是必不可少的。激动剂结合位点的这一特征存在于研究更少的乙酰胆碱门控氯离子通道中(PLoS pathog 2020 16(4)：e1008396)。这突出表明，尼古丁受体可以呈现一个独特的药效团，为选择性驱虫化学物质提供一条途径。重要的是，原型Eat-2控制着模式生物线虫的摄食，并在包括植物寄生线虫在内的其他线虫中发现。该提案将寻求确定EAT-2和其他非邻近乙酰胆碱受体的选择性药理作用。学生将探索它们在关键植物寄生线虫中的功能作用，并解决如果这一未被调查的神经肌肉功能决定因素可以作为化学缓解线虫害虫的可靠目标。

Chemicals acting on neuromuscular transmission that control insects and nematode movement have provided successful pest management. An important criterion in ongoing development of this approach is selective toxicityThis allows treatments to act as potent pest control while having limited deleterious effect on non-harmful organisms. Conventionally, this is addressed by defining receptor classes selectively found between phyla and species. We have recently established a tissue selective sensitivity in the cholinergic transmission that pharmacologically discriminates between locomotion and feeding in nematodes (Gonzalez, J Biol Chem in submission). This difference is due to the distinct nature of the major acetylcholine receptors underpinning cholinergic transmission at these neuromuscular junctions. Pharyngeal transmission is dependent on an under investigated excitatory nicotinic acetylcholine receptor called EAT-2. This receptor is among an emerging class of homo-oligomeric receptors activated by the endogenous agonist acetylcholine. However, EAT-2 is unique amongst nicotinic receptors in lacking the signature vicinal cysteine in the highly evolutionary conserved loop C of the agonist binding site. It was previously assumed that this vicinal cysteine was essential for acetylcholine receptor activation in both homo and hetero-oligomeric receptors. This feature of the agonist binding site exists in the even more poorly investigated acetylcholine gated chloride channels (PLoS Pathog 2020 16(4):e1008396). This highlights that nicotinic receptors can present a distinct pharmacophore to provide a route to selective anthelmintic chemicals. Importantly, the prototype EAT-2 controls feeding in the model organism C. elegans and is found in other nematodes including the plant parasitic nematodes. The proposal will seek to identify selective pharmacology of EAT-2 and other non-vicinal acetylcholine receptors. The student will probe their functional role in key plant parasitic nematodes and address if this under investigated determinant of the neuromuscular function can act as credible target for the chemical mitigation of nematode pests.