沙门氏菌效应蛋白SopB288～309肽段介导SopB依赖的HeLa细胞AKT的磷酸化研究

The 288- 309 Peptide of SopB Mediates the SopB-dependent AKT Phosphorylation in HeLa Cells

[目的]研究沙门氏菌效应蛋白SopB中跨膜疏水结构域288-309肽段对受SopB诱导的HeLa细胞Akt磷酸化激活中的功能。[方法]通过重叠延伸PCR的方法构建SopB第288~309位肽段缺失突变基因,并将该基因在HeLa细胞中进行异位表达,与野生型SopB基因进行比较,确定缺失的第288~309位间肽段在受SopB诱导的Akt磷酸化激活中的作用。[结果]与空载体对照相比较,在HeLa细胞中表达野生型SopB重组质粒明显激活了pAkt473的磷酸化,而在HeLa细胞中表达SopB缺失突变体SopBΔ288-309时,则检测不到pAkt473的磷酸化激活。[结论]SopB表达激活HeLa细胞pAkt473的磷酸化与其第288~309位肽段的功能直接相关,该跨膜疏水结构域的缺失导致SopB蛋白不能亚细胞定位至细胞膜,从而导致SopBΔ288-309对pAkt473磷酸化激活功能的丧失。

[ Objective ] To investigate the hydrophobic membrane spanning domain 288 - 309 peptide in the sequence of SopB that related to the SopB-dependent activation and pbosphorylation of Akt in HeLa cells. [ Method] The SopB^△288-309 mutant was amplified with gene splicing by over- lap extension PCR （SOE PCR） and constructed into pCDNA4.0 vector. Subsequently, the capability of the SopB^△288-309 mutant to the activation and phosphorylation of Akt in HeLa cells was measured in comparison with the wide type SopB in order to assure the role of peptide spanning 288 -309 peptide. [ Result ] In contrast with the null activation of empty vector, the overexpression of wide type SopB in HeLa cells obviously in- duces the activation and phosphorylation of pAkt473. Absolutely different with wide type SopB, the overexpression of SopB^△288-309 mutant abrogates the activation and phosphorylation of pAkt^73 in HeLa cells. [ Conclusion] The peptide spamling 288-309 peptide is vital to the SopB-dependent pAkh7~ activation in HeLa cells. The deletion of the hydrophobic membrane spanning domain of SopB lead to that SopB could not subcellularly lo- calize to cell membrane, which might be the reason to the loss of the SopB^△288-309 mutant to the phosphorylation and activation of pAkt473.