Involvement of Manduca sexta peptidoglycan recognition protein-1 in the recognition of bacteria and activation of prophenoloxidase system.
Involvement of Manduca sexta peptidoglycan recognition protein-1 in the recognition of bacteria and activation of prophenoloxidase system.
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DOI：
10.1016/j.ibmb.2010.04.008
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发表时间：
2010-06
影响因子：
3.8
通讯作者：
Jiang, Haobo
中科院分区：
文献类型：
--
作者：
Sumathipala, Niranji;Jiang, Haobo
尽管肽聚糖识别蛋白 (PGRP) 在检测细菌和促进免疫方面的重要性在果蝇和其他昆虫物种中已得到充分认识，但 PGRP 在烟草天蛾 (Manduca sexta) 中的这种作用尚未通过实验确定。在本研究中，我们从杆状病毒昆虫细胞表达系统中纯化了M. sexta PGRP1，测试了其与肽聚糖和完整细菌的关联，并探讨了其与幼虫血淋巴中酚氧化酶原激活系统的可能联系。序列比较表明PGRP1不是酰胺酶并且缺乏与内消旋二氨基庚二酸肽聚糖(DAP-PG)的羧基相互作用的残基。 M. sexta PGRP1基因在脂肪体中低水平表达，注射大肠杆菌后mRNA浓度显着升高。一致地，幼虫血浆中的蛋白质浓度在免疫攻击后以时间依赖性方式增加。纯化的重组 PGRP1 特异性结合大肠杆菌的可溶性 DAP-PG，但不结合金黄色葡萄球菌的可溶性 Lys 型 PG。此外，该识别蛋白与来自藤黄微球菌、巨大芽孢杆菌和枯草芽孢杆菌的不溶性PG完全结合，而尽管细菌细胞的肽聚糖暴露在细胞表面，但其与细菌细胞的结合较低。在没有微生物激发子的情况下，将 PGRP1 添加到幼虫的血浆中后，酚氧化酶原激活呈浓度依赖性增加。与往常一样，血浆与肽聚糖或细菌细胞一起孵育后，酚氧化酶活性增加。当不溶性藤黄杆菌或巨大芽孢杆菌 PG 或可溶性大肠杆菌 PG 和 PGRP1 同时存在时，这些增加变得更加明显。统计分析表明PGRP1和这些PG之间的相互作用引起了协同效应。总而言之，这些结果表明 PGRP1 是 M. sexta 酚氧化酶激活系统的成员，该系统识别某些细菌的肽聚糖并启动宿主防御反应。纯化的 PG 和完整细菌之间无法解释的差异清楚地反映了我们对 PGRP1 介导的识别及其如何导致 proPO 激活普遍缺乏了解。
Although the importance of peptidoglycan recognition proteins (PGRPs) in detecting bacteria and promoting immunity is well recognized in Drosophila melanogaster and other insect species, such a role has not yet been experimentally established for PGRPs in the tobacco hornworm, Manduca sexta. In this study, we purified M. sexta PGRP1 from the baculovirus-insect cell expression system, tested its association with peptidoglycans and intact bacteria, and explored its possible link with the prophenoloxidase activation system in larval hemolymph. Sequence comparison suggested that PGRP1 is not an amidase and lacks residues for interacting with the carboxyl group of meso-diaminopimelic acid-peptidoglycans (DAP-PGs). M. sexta PGRP1 gene was constitutively expressed at a low level in fat body, and the mRNA concentration became much higher after an injection of Escherichia coli. Consistently, the protein concentration in larval plasma increased in a time-dependent manner after the immune challenge. Purified recombinant PGRP1 specifically bound to soluble DAP-PG of E. coli but not to soluble Lys-type PG of Staphylococcus aureus. In addition, this recognition protein completely bound to insoluble PGs from Micrococcus luteus, Bacillus megaterium and Bacillus subtilis, whereas its association with the bacterial cells was low even though their peptidoglycans are exposed on the cell surface. After PGRP1 had been added to plasma of naïve larvae in the absence of microbial elicitor, there was a concentration-dependent increase in prophenoloxidase activation. Phenoloxidase activity, as usual, increased after the plasma was incubated with peptidoglyans or bacterial cells. These increases became more prominent when insoluble M. luteus or B. megaterium PG or soluble E. coli PG and PGRP1 were both present. Statistic analysis suggested a synergistic effect caused by interaction between PGRP1 and these PGs. Taken together, these results indicated that PGRP1 is a member of the M. sexta prophenoloxidase activation system, which recognizes peptidoglycans from certain bacteria and initiates the host defense response. The unexplained difference between the purified PGs and intact bacteria clearly reflects our general lack of understanding of PGRP1-mediated recognition and how it leads to proPO activation.
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DOI：
10.1073/pnas.0610924104
发表时间：
2007-04-17
影响因子：
11.1
作者：
Park, Ji-Won;Kim, Chan-Hee;Lee, Bok-Luel
通讯作者：
Lee, Bok-Luel
DOI：
10.1016/j.cbpb.2007.03.005
发表时间：
2007-07-01
影响因子：
2.2
作者：
Onoe, Hiroko;Matsumoto, Akiyoshi;Morishima, Isao
通讯作者：
Morishima, Isao
DOI：
10.1073/pnas.0407856101
发表时间：
2004-12-07
影响因子：
11.1
作者：
Guan, RJ;Roychowdhury, A;Mariuzza, RA
通讯作者：
Mariuzza, RA
影响因子：
4.8
作者：
Ochiai, M;Ashida, M
通讯作者：
Ashida, M
影响因子：
3.4
作者：
DUNN, PE;DRAKE, DR
通讯作者：
DRAKE, DR