LPS影响p38蛋白在单核细胞内定位

目的： 探讨 LPS作用下p38蛋白激酶激活的动力学特点及其在细胞内超微结构中的定位。方法： 应用激酶活性测定、胶体金标记的免疫电镜技术观察LPS刺激前后p38蛋白激酶的动力学特点及在单核细胞株Raw264.7中的分布特征。结果： 动力学检测结果显示，LPS作用后15 min，p38磷酸化活性明显升高，30 min达到高峰，2 h达基线水平；p38在LPS浓度为100 μg/L时达最大激活效应。超微定位结果显示，未受刺激的及EGF刺激的细胞，p38在胞浆和胞核中金颗粒呈弥散性分布，金颗粒弥散在细胞的各个部分，如细胞质中线粒体、内质网、溶酶体；单核细胞株受到LPS刺激后，细胞核区的金颗粒明显增多，而胞浆区域的金颗粒显著减少。结论： 单核细胞株Raw264.7受LPS刺激后，其p38蛋白激酶由胞浆移位到胞核。

Effect of LPS on intracellular localization of p38 protein kinase in Raw264.7 cells

AIM: To investigate the activation dynamics and the intracellular localization of p38 protein kinase in Raw264.7 cells after lipopolysaccharide (LPS) stimulation.METHODS: Protein kinase assay and immunogold electron microscope technique were used to check the activation dynamics and distribution of p38 MAPK in Raw264.7 cells before and after LPS stimulation. RESULTS: The kinase assay results showed that a marked increase in p38 activity was detected 15 min after LPS treatment, and reached maximal activity 30 min post stimulation, then dropped down and got closed to the pre-stimulated level 2 h later. The optimal LPS concentration for treatment was 100 μg/L. The immunogold electron microscope data showed that p38 spread evenly in every part of the cytosol of the non-stimulated and EGF stimulated Raw264.7 cells, such as endoplasmic reticulum, mitochondria, lysosome, while the golden granules intensity in the cytosol area decreased and in the nuclear area increased significantly after LPS stimulation.CONCLUSION: p38 MAPK moves to the nuclei of Raw264.7 cells on account of stimulation by LPS.