Oxidation regulates the inflammatory properties of the murine S100 protein S100A8
Oxidation regulates the inflammatory properties of the murine S100 protein S100A8
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DOI：
10.1074/jbc.274.13.8561
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发表时间：
1999-03-26
影响因子：
4.8
通讯作者：
Geczy, CL
中科院分区：
文献类型：
--
作者：
Harrison, CA;Raftery, MJ;Geczy, CL
骨髓细胞衍生的钙结合鼠蛋白S100 A8分泌为皮摩尔浓度的趋化因子，刺激骨髓细胞向炎症部位的募集。S100 A8可能暴露于氧代谢物，特别是次氯酸盐，这是炎症部位活化的中性粒细胞产生的主要氧化剂。在这里，我们表明，次氯酸盐氧化S100 A8的单个Cys残留物（Cys（41））。电喷雾质谱和SDS-聚丙烯酰胺凝胶电泳分析表明，低浓度的次氯酸盐（40 μ M）将70-80%的S100 A8转化为二硫键连接的同源二聚体，质量为20，707 Da，比预期高92 Da，表明敏感氨基酸（可能是蛋氨酸）的额外氧化。佛波醇12-肉豆蔻酸酯13-乙酸酯激活分化的HL-60粒细胞产生的氧化爆发，足以有效地氧化外源性S100 A8在10分钟内，结果牵连髓过氧化物酶系统的参与。此外，二硫键连接的二聚体在内毒素诱导的肺损伤小鼠的肺灌洗液中被鉴定。S100 A8二聚体在体内没有趋化活性，不能募集白细胞。重组Ala（41）S100 A8的阳性趋化活性表明Cys 41不是功能所必需的，并表明共价二聚化可能在结构上改变趋化铰链结构域的可及性。二硫键依赖性二聚化可能是控制S100 A8引起的白细胞募集的生理学上重要的调节机制。
The myeloid cell-derived calcium-binding murine protein, S100A8, is secreted to act as a chemotactic factor at picomolar concentrations, stimulating recruitment of myeloid cells to inflammatory sites, S100A8 may be exposed to oxygen metabolites, particularly hypochlorite, the major oxidant generated by activated neutrophils at inflammatory sites. Here we show that hypochlorite oxidizes the single Cys residue (Cys(41)) of S100A8. Electrospray mass spectrometry and SDS-polyacrylamide gel electrophoresis analysis indicated that low concentrations of hypochlorite (40 mu M) converted 70-80% of S100A8 to the disulfide-linked homodimer, The mass was 20,707 Da, 92 Da more than expected, indicating additional oxidation of susceptible amino acids (possibly methionine). Phorbol 12-myristate 13-acetate activation of differentiated HL-60 granulocytic cells generated an oxidative burst that was sufficient to efficiently oxidize exogenous S100A8 within 10 min, and results implicate involvement of the myeloperoxidase system. Moreover, disulfide-linked dimer was identified in lung lavage fluid of mice with endotoxin-induced pulmonary injury. S100A8 dimer was inactive in chemotaxis and failed to recruit leukocytes in vivo. Positive chemotactic activity of recombinant Ala(41)S100A8 indicated that Cys41 was not essential for function and suggested that covalent dimerization may structurally modify accessibility of the chemotactic hinge domain. Disulfide-dependent dimerization may be a physiologically significant regulatory mechanism controlling S100A8-provoked leukocyte recruitment.