Structural Analysis of Lipopolysaccharide-receptor on hemocytes of horseshoe crab

鲎血细胞脂多糖受体的结构分析

• 批准号: 13680693
• 负责人: KAWABATA Shun-ichiro
• 金额: $ 2.69万
• 依托单位: Kyushu University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 2001
• 资助国家: 日本
• 起止时间: 2001 至 2002
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-13680693/
• 关键词: Gram-negative bacteria; Exocytosis; Lipopolysaccharide; LPS receptor; G protein; カブトガニ; LPS; リピドA

The innate immune system is a sensitive non-self-recognizing cascade triggered by microbial cell wall constituents called pathogen-associated molecular patterns (PAMPs), such as lipopolysaccharides (LPS) of Gram-negative bacteria, β-1,3-glucans of fungi, and peptidoglycans of Gram-positive bacteria. These PAMPs are recognized via a set of germ line-encoded receptros of innate immune system called pattern recognition receptors. Recent studies have revealed that insects and mannals conserve a signaling pathway of the innate immune system through cell-surface receptors, Toll and Toll-like receptors (TLRs). In mammals, TLRs on specialized antigen-presenting cells function as signal transducers by way of NF-kB, leading to the production of pro-inflammatory cytokines and the expression of constimulatory molecules on the cell surface, which are necessary to activate naive T cells; TLRs are possibly assembled at the cell membrane as signaling receptor complexes. In the horseshoe crab innate immunity, LPS-induced exocytosis of granular hemocytes is a key phenomenon to fight infectious microorganisms: the stimulation by LPS induces the secretion of various defense molecules stored in granules of hemocytes. Here we show that a granular component factor C, an LPS-recognizing serine protease zymogen initiating the hemolymph coagulation cascade, also exists on the surface of hemocytes. Our data demonstrate that the complex of the activated factor C with LPS is not required but the proteolytic activity is required and sufficient to trigger the exocytosis through a heterotrimeric GTP-binding protein-mediating signaling pathway. We conclude that the serine protease zymogen on hemocytes functions as a pattern recognition receptor for LPS.

先天免疫系统是一个敏感的非自我识别级联反应，由称为病原体相关分子模式（PAMPs）的微生物细胞壁成分触发，如革兰氏阴性菌的脂多糖（LPS）、真菌的β-1,3-葡聚糖和革兰氏阳性菌的肽聚糖。这些PAMPs是通过先天免疫系统中一组被称为模式识别受体的种系编码受体识别的。最近的研究表明，昆虫和人类通过细胞表面受体Toll和Toll样受体（TLRs）保存先天免疫系统的信号通路。在哺乳动物中，特异性抗原呈递细胞上的tlr通过NF-kB作为信号转导器，导致促炎细胞因子的产生和细胞表面刺激分子的表达，这是激活初始T细胞所必需的；tlr可能作为信号受体复合物在细胞膜上组装。在马蹄蟹先天免疫中，LPS诱导的颗粒血细胞胞吐是马蹄蟹对抗感染性微生物的关键现象：LPS的刺激诱导储存在颗粒血细胞中的各种防御分子的分泌。在这里，我们发现颗粒成分因子C，一种启动血淋巴凝血级联的识别lps的丝氨酸蛋白酶酶原，也存在于血细胞表面。我们的数据表明，活化因子C与LPS的复合物不是必需的，但蛋白质水解活性是必需的，并且足以通过异源三聚体gtp结合蛋白介导的信号通路触发胞外分泌。我们得出结论，血细胞上的丝氨酸蛋白酶酶原作为LPS的模式识别受体发挥作用。

项目成果

Kawabata S.et al.: "Innate Immunity"Humana Press Inc.. 432 (2002)

Kawabata S.et al.：“先天免疫”Humana Press Inc.. 432 (2002)

Osaki, T.et al.: "Proline-rich cell surface antigens of horseshoe crab hemocytes are substrates for protein cross-linking with a clotting protein coagulin"J.Biol.Chem.. 277・42. 40084-40090 (2002)

Osaki, T. 等：“鲎血细胞富含脯氨酸的细胞表面抗原是与凝血蛋白凝固蛋白交联的底物”J.Biol.Chem.. 277・42 (2002)。

Takaki, Y. et al.: "Duplicated binding site for 1,3 β-D-glucan in the horseshoe crab coagulation factor G: Implications for a molecular basis of the pattern recognition in innate immunity.."J. Biol. Chem.. 277. 1428-14287 (2002)

Takaki, Y. 等人：“鲎凝固因子 G 中 1,3 β-D-葡聚糖的重复结合位点：对先天免疫模式识别的分子基础的影响”。 277. 1428-14287 (2002)

Suetake, T., et al.: "Production and characterization of recombinant Tachycitin, the chitin-binding protein."Protein Engineering. 15. 736-769 (2002)

Suetake, T. 等人：“重组 Tachycitin（几丁质结合蛋白）的生产和表征。”蛋白质工程。

Kawabata et al.: "Innate Immunity"Humana Press Inc.. 432 (2002)

Kawabata 等人：“先天免疫”Humana Press Inc.. 432 (2002)