Which acetylcholinesterase functions as the main catalytic enzyme in the Class Insecta?
Which acetylcholinesterase functions as the main catalytic enzyme in the Class Insecta?
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DOI：
10.1016/j.ibmb.2012.11.004
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发表时间：
2013-01-01
影响因子：
3.8
通讯作者：
Lee, Si Hyeock
中科院分区：
文献类型：
--
作者：
Kim, Young Ho;Lee, Si Hyeock
大多数昆虫具有两种不同的乙酰胆碱酯酶（ache）（即AChEl和AChE2，分别由ace I和ace2基因编码）。在这两种ache中，AChEl被认为是一种主要的催化酶，基于其较高的表达水平和频繁观察到的与杀虫剂抗性相关的点突变。为了研究AChEl和AChE2的进化分布，我们确定了AChE在18个目的几种昆虫中具有中心催化功能。头部的主要催化活性由天然聚丙烯酰胺凝胶电泳和Western blotting测定，使用AChEl-和ache2特异性抗体。100种昆虫中，有67种AChEl活性较高；因此，AChEl被认为是主要的催化酶。从古翅目到膜翅目，其余33种中，AChE2作为主要的催化酶主要表达。这些发现挑战了AChE1是昆虫中除环裂外唯一的主要催化酶的普遍观点，并进一步证明了AChE2作为主要酶的特化或AChE2取代AChEl功能是相当普遍的事件，在昆虫进化过程中有多个独立的起源。据推测，通过选择性剪接产生多个AChE2异构体，在环切中AChE2功能替代AChEl的过程中，导致了ace1的丢失。然而，在高等社会膜翅目昆虫中，AChE2作为主要的催化酶的存在，为AChE2在功能上替代AChEl而不损失ace1提供了一个案例。目前的研究将为AChE的进化提供有价值的见解：AChE已被专门用作主要的催化酶，并成为不同昆虫物种杀虫剂的主要靶点。(C) 2012 Elsevier Ltd.版权所有。
Most insects possess two different acetylcholinesterases (AChEs) (i.e., AChEl and AChE2; encoded by ace I and ace2 genes, respectively). Between the two AChEs, AChEl has been proposed as a major catalytic enzyme based on its higher expression level and frequently observed point mutations associated with insecticide resistance. To investigate the evolutionary distribution of AChEl and AChE2, we determined which AChE had a central catalytic function in several insect species across 18 orders. The main catalytic activity in heads was determined by native polyacrylamide gel electrophoresis in conjunction with Western blotting using AChEl- and AChE2-specific antibodies. Of the 100 insect species examined, 67 species showed higher AChEl activity; thus, AChEl was considered as the main catalytic enzyme. In the remaining 33 species, ranging from Palaeoptera to Hymenoptera, however, AChE2 was predominantly expressed as the main catalytic enzyme. These findings challenge the common notion that AChE1 is the only main catalytic enzyme in insects with the exception of Cyclorrhapha, and further demonstrate that the specialization of AChE2 as the main enzyme or the replacement of AChEl function with AChE2 were rather common events, having multiple independent origins during insect evolution. It was hypothesized that the generation of multiple AChE2 isoforms by alternative splicing allowed the loss of ace1 during the process of functional replacement of AChEl with AChE2 in Cyclorrhapha. However, the presence of AChE2 as the main catalytic enzyme in higher social Hymenoptera provides a case for the functional replacement of AChEl with AChE2 without the loss of ace1. The current study will provide valuable insights into the evolution of AChE: which AChE has been specialized as the main catalytic enzyme and to become the main target for insecticides in different insect species. (C) 2012 Elsevier Ltd. All rights reserved.