Recognition of microbial molecular patterns and stimulation of prophenoloxidase activation by a β-1,3-glucanase-related protein in Manduca sexta larval plasma.
Recognition of microbial molecular patterns and stimulation of prophenoloxidase activation by a β-1,3-glucanase-related protein in Manduca sexta larval plasma.
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DOI：
10.1016/j.ibmb.2011.01.010
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发表时间：
2011-05
影响因子：
3.8
通讯作者：
Jiang H
中科院分区：
文献类型：
--
作者：
Wang Y;Sumathipala N;Rayaprolu S;Jiang H
检测病原入侵者是多细胞生物成功防御反应的重要第一步。在本研究中，我们从烟草天蛾Manduca sexta中鉴定了一个β-1，3-葡聚糖酶相关蛋白超家族的新成员。这种蛋白质，命名为微生物结合蛋白（MBP），在序列上与家蚕革兰氏阴性菌结合蛋白有61%的相同性，但与M. sexta β-1，3-葡聚糖识别蛋白-1和2。其mRNA水平在免疫攻击的幼虫的血细胞和脂肪体中强烈上调，沿着血浆蛋白浓度的增加。我们表达了M。sexta MBP在杆状病毒-昆虫细胞系统中的表达。与完整的细菌和真菌有关的纯化蛋白质。它特异性结合脂磷壁酸，脂多糖，二氨基庚二酸型肽聚糖（DAP-PG）从大肠杆菌和枯草芽孢杆菌，但较少，海带多糖或赖氨酸型PG从金黄色葡萄球菌。复杂的结合模式受到其他血浆因子和其他微生物表面分子的影响。在不存在任何微生物激发子的情况下，将不同量的MBP与幼虫血浆在冰上孵育后，酚氧化酶（PO）活性发生浓度依赖性增加。在血浆和细菌或真菌细胞壁组分的混合物中也观察到活性增加。当MBP和血浆的混合物中含有DAP-PG、藤黄微球菌Lys-PG或脂磷壁酸时，酚氧化酶原（proPO）活化变得更加突出。统计分析表明，MBP与这些激发子之间的相互作用可协同增强proPO的激活，而S. aureus Lys-PG、脂多糖、凝胶多糖或海带多糖。这些数据表明M. sexta MBP是监视机制的一个组成部分，通过与其他模式识别分子和丝氨酸蛋白酶一起工作，触发proPO激活系统。
Detection of pathogenic invaders is the essential first step of a successful defense response in multicellular organisms. In this study, we have identified a new member of the β-1,3-glucanase-related protein superfamily from the tobacco hornworm Manduca sexta. This protein, designated microbe binding protein (MBP), is 61% identical in sequence to Bombyx mori Gram-negative bacteria binding protein, but only 34-36% identical to M. sexta β-1,3-glucan recognition protein-1 and 2. Its mRNA levels were strongly up-regulated in hemocytes and fat body of immune challenged larvae, along with an increase in concentration of the plasma protein. We expressed M. sexta MBP in a baculovirus-insect cell system. The purified protein associated with intact bacteria and fungi. It specifically bound to lipoteichoic acid, lipopolysaccharide, diaminopimelic acid-type peptidoglycans (DAP-PGs) from Escherichia coli and Bacillus subtilis, but less so to laminarin or Lys-type PG from Staphylococcus aureus. The complex binding pattern was influenced by other plasma factors and additional microbial surface molecules. After different amounts of MBP had been incubated with larval plasma on ice, a concentration-dependent increase in phenoloxidase (PO) activity occurred in the absence of any microbial elicitor. The activity increase was also observed in the mixture of plasma and a bacterial or fungal cell wall component. The prophenoloxidase (proPO) activation became more prominent when DAP-PGs, Micrococcus luteus Lys-PG, or lipoteichoic acid was included in the mixture of MBP and plasma. Statistic analysis suggested that a synergistic enhancement of proPO activation was caused by an interaction between MBP and these elicitors, but not S. aureus Lys-PG, lipopolysaccharide, curdlan, or laminarin. These data indicate that M. sexta MBP is a component of the surveillance mechanism and, by working together with other pattern recognition molecules and serine proteinases, triggers the proPO activation system.