Huang Qiu Tang, Sheng Cheng Wang, Jones Andrew K, Jiang Jie, Tang Tao, Han Zhao Jun, Zhao Chun Qing
College of Plant Protection, Nanjing Agricultural University, Nanjing 210095, P. R. China.
Department of Biological and Medical Sciences, Oxford Brookes University, Oxford OX3 0BP, U.K.
J Agric Food Chem. 2021 Oct 6;69(39):11582-11591. doi: 10.1021/acs.jafc.1c00385. Epub 2021 Sep 23.
The ionotropic γ-aminobutyric acid (iGABA) receptor is commonly considered as a fast inhibitory channel and is an important insecticide target. Since 1990, RDL, LCCH3, and GRD have been successively isolated and found to be potential subunits of the insect iGABA receptor. More recently, one orphan gene named 8916 was found and considered to be another potential iGABA receptor subunit according to its amino acid sequence. However, little information about 8916 has been reported. Here, the 8916 subunit from was studied to determine whether it can form part of a functional iGABA receptor by co-expressing this subunit with CsRDL1 or CsLCCH3 in the system. Cs8916 or CsLCCH3 did not form functional ion channels when expressed alone. However, Cs8916 was able to form heteromeric ion channels when expressed with either CsLCCH3 or CsRDL1. The recombinant heteromeric Cs8916/LCCH3 channel was a cation-selective channel, which was sensitive to GABA or β-alanine. The current of the Cs8916/LCCH3 channel was inhibited by dieldrin, endosulfan, fipronil, or ethiprole. In contrast, fluralaner, broflanilide, and avermectin showed little effect on the Cs8916/LCCH3 channel (ICs > 10 000 nM). The Cs8916/RDL1 channel was sensitive to GABA, but was significantly different in EC and for GABA to those of homomeric CsRDL1. Fluralaner, fipronil, or dieldrin showed antagonistic actions on Cs8916/RDL1. In conclusion, Cs8916 is a potential iGABA receptor subunit, which can interact with CsLCCH3 to generate a cation-selective channel that is sensitive to several insecticides. Also, as Cs8916/RDL1 has a higher EC than homomeric CsRDL1, Cs8916 may affect the physiological functions of CsRDL1 and therefore play a role in fine-tuning GABAergic signaling.
离子型γ-氨基丁酸（iGABA）受体通常被认为是一种快速抑制性通道，并且是重要的杀虫剂作用靶标。自1990年以来，RDL、LCCH3和GRD已相继被分离出来，并被发现是昆虫iGABA受体的潜在亚基。最近，一个名为8916的孤儿基因被发现，根据其氨基酸序列，它被认为是另一个潜在的iGABA受体亚基。然而，关于8916的信息报道很少。在此，对来自[具体来源未提及]的8916亚基进行了研究，通过在[具体系统未提及]系统中将该亚基与CsRDL1或CsLCCH3共表达，以确定它是否能成为功能性iGABA受体的一部分。单独表达时，Cs8916或CsLCCH3不能形成功能性离子通道。然而，当与CsLCCH3或CsRDL1一起表达时，Cs8916能够形成异源离子通道。重组的异源Cs8916/LCCH3通道是一种阳离子选择性通道，对GABA或β-丙氨酸敏感。Cs8916/LCCH3通道的电流受到狄氏剂﹑硫丹﹑氟虫腈或乙虫腈的抑制。相比之下，氟虫兰﹑溴虫氟苯双酰胺和阿维菌素对Cs8916/LCCH3通道几乎没有影响（IC50＞10000 nM）。Cs8916/RDL1通道对GABA敏感，但在GABA的EC50和[其他相关参数未提及]方面与同源性CsRDL1通道有显著差异。氟虫兰﹑氟虫腈或狄氏剂对Cs8916/RDL1有拮抗作用。总之，Cs8916是一个潜在的iGABA受体亚基，它可以与CsLCCH3相互作用产生一个对几种杀虫剂敏感的阳离子选择性通道。此外，由于Cs8916/RDL1的EC50高于同源性CsRDL1，Cs8916可能会影响CsRDL1的生理功能，因此在微调GABA能信号传导中发挥作用。
