A novel ML protein from Manduca sexta may function as a key accessory protein for lipopolysaccharide signaling
A novel ML protein from Manduca sexta may function as a key accessory protein for lipopolysaccharide signaling
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DOI：
10.1016/j.molimm.2008.02.006
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发表时间：
2008-05-01
影响因子：
3.6
通讯作者：
Yu, Xiao-Qiang
中科院分区：
文献类型：
--
作者：
Ao, Jing-qun;Ling, Erjun;Yu, Xiao-Qiang
革兰氏阴性菌外膜脂多糖（LPS）是最重要的病原体相关分子模式之一，也是天然免疫的一种强有力的激发子。在人类中，TLR 4（Toll样受体4）和MD-2（髓样分化-2）形成受体复合物以将LPS信号传递到细胞中。然而，在无脊椎动物中，识别LPS的受体尚未确定。本文报道了烟草天蛾ML（MD-2-related lipid-recognition）蛋白的纯化、鉴定和cDNA克隆。克隆了该菌株的全长cDNA。Sexta NIL蛋白命名为MsML-1，全长532 bp，开放阅读框为456 bp，编码151个氨基酸，含有NIL结构域。MsML-1是一种分泌型糖蛋白，其mRNA在脂肪体和血细胞中表达。免疫攻击不诱导脂肪体和血细胞中MsML-1 mRNA的表达水平以及血淋巴中MsML-1蛋白的表达水平。重组MsML-1蛋白特异性结合来自几种革兰氏阴性细菌和LPS Re突变体的LPS，以及脂质A，但不结合KDO（2-酮基-3-脱氧辛酸酯）。我们的研究结果表明，MsML-1可能作为一个关键的辅助蛋白LPS信号在M。sexta抗革兰氏阴性菌感染。(c)2008年爱思唯尔有限公司保留所有战斗。
Lipopolysaccharide (LPS) present on the outer membrane of Gram-negative bacteria is one of the most important pathogen-associated molecular patterns and a potent elicitor in innate immunity. In human, TLR4 (Toll-like receptor 4) and MD-2 (myeloid differiation-2) form a receptor complex to transduce the LPS signal into cells. However, in invertebrates, receptors that recognize LPS have not been determined. Here we report the purification, characterization and cDNA cloning of an ML (MD-2-related lipid-recognition) protein from the tobacco hornworm Manduca sexta. The full-length cDNA of this M. sexta NIL protein, named MsML-1, is 532 bp with an open reading frame of 456 bp that encodes a polypeptide of 151 amino acids containing an NIL domain. MsML-1 is a secreted glycoprotein and its mRNA is expressed in fat body and hemocytes. The expression level of MsML-1 mRNA in fat body and hemocytes as well as MsML-1 protein in hemolymph are not induced by immune challenge. Recombinant MsML-1 protein specifically binds to LPS from several Gram-negative bacteria and LPS Re mutant, as well as to lipid A, but not to KDO (2-keto-3-deoxyoctonate). Our results suggest that MsML-1 may function as a key accessory protein for LPS signaling in M. sexta against Gram-negative bacterial infection. (c) 2008 Elsevier Ltd. All fights reserved.