Peptidoglycan activation of the proPO-system without a peptidoglycan receptor protein (PGRP)?
Peptidoglycan activation of the proPO-system without a peptidoglycan receptor protein (PGRP)?
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DOI：
10.1016/j.dci.2010.08.005
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发表时间：
2011-01-01
影响因子：
2.9
通讯作者：
Soderhall, Irene
中科院分区：
文献类型：
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作者：
Liu, Haipeng;Wu, Chenglin;Soderhall, Irene
模式识别受体对微生物多糖的识别触发酚氧化酶原（proPO）级联反应，导致黑色素合成及其在入侵病原体表面的沉积。几种伪装样蛋白和丝氨酸蛋白酶同源物已被证明参与昆虫中的proPO激活。在这项研究中，一个新的丝氨酸蛋白酶同源物，P1-SPH 2，被发现和分离作为一个30 kDa的蛋白质从淡水小龙虾，细鳞螯虾的血细胞，通过其结合特性的部分溶菌酶消化或TCA处理的不溶性赖氨酸（Lys）型肽聚糖（PGN）和可溶性多聚赖氨酸型PGN。在几种不同的PGN结合试验中还发现了另外两种蛋白质，P1-SPH 1和脂多糖-和β-1，3-葡聚糖-结合蛋白（LGBP）。然而，没有检测到PGRP同源物。也没有任何推定的PGRP后，发现搜索可用的甲壳类动物序列数据库。如果在螯虾造血组织细胞培养物中进行Pl-SPH 2、Pl-SPH 1或LGBP的RNA干扰，则在可溶性Lys型PGN激活proPO系统后，导致PO活性降低。两者合计，我们报告的第一次，赖氨酸型PGN是一个触发器的proPO系统激活的甲壳类动物和两个PI-SPlis参与这种激活可能通过形成一个复杂的LGBP和没有PGRP。(C)2010爱思唯尔有限公司版权所有。
Recognition of microbial polysaccharide by pattern recognition receptors triggers the prophenoloxidase (proPO) cascade, resulting in melanin synthesis and its deposition on the surface of invading pathogens. Several masquerade-like proteins and serine proteinase homologues have been shown to be involved in the proPO activation in insects. In this study, a novel serine proteinase homologue, Pl-SPH2, was found and isolated as a 30 kDa protein from hemocytes of the freshwater crayfish, Pacifastocus leniusculus, by its binding property to a partially lysozyme digested or TCA-treated insoluble Lysine (Lys)-type pepticloglycan (PGN) and soluble polymeric Lys-type PGN. Two other proteins, the Pl-SPH1 and lipopolysaccharide- and beta-1,3-glucan-bincling protein (LGBP) were also found in the several different PGN-binding assays. However no PGRP homologue was detected. Neither was any putative PGRP found after searching available crustacean sequence databases. If RNA interference of Pl-SPH2, Pl-SPH1 or LGBP in the crayfish hematopoietic tissue cell culture was performed, it resulted in lower PO activity following activation of the proPO-system by soluble Lys-type PGN. Taken together, we report for the first time that Lys-type PGN is a trigger of proPO-system activation in a crustacean and that two Pl-SPlis are involved in this activation possibly by forming a complex with LGBP and without a PGRP. (C) 2010 Elsevier Ltd. All rights reserved.