Sphingomyelin is important for the cellular entry and intracellular localization of Helicobacter pylori VacA
Sphingomyelin is important for the cellular entry and intracellular localization of Helicobacter pylori VacA
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DOI：
10.1111/j.1462-5822.2010.01487.x
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发表时间：
2010-10-01
影响因子：
3.4
通讯作者：
Blanke, Steven R.
中科院分区：
文献类型：
--
作者：
Gupta, Vijay R.;Wilson, Brenda A.;Blanke, Steven R.
质膜鞘磷脂（SM）与幽门螺杆菌空泡毒素（VacA）结合在上皮细胞表面.要评估的重要性SM的VacA细胞进入，我们的特点是毒素的摄取和贩运细胞内富含合成的SM变体，其细胞内的贩运特性是严格依赖于其鞘脂骨架的酰基链长度。虽然毒素与细胞表面的结合与酰基链长度无关，但富含SM的12-或18-碳酰基链变体（例如C12-SM或C18-SM）的细胞比富含较短的2-或6-碳变体（例如C2-SM或C6-SM）的细胞对VacA更敏感，如毒素诱导的细胞空泡化所示。在C18-SM富集的细胞中，VacA通过先前描述的Cdc 42依赖性胞饮机制进入细胞，最初定位于GPI富集的囊泡，并最终被运输到Rab 7/Lamp 1隔室。相反，在C2-SM富集细胞内，VacA通过Cdc 42独立机制以较慢的速率被吸收，并被运输到Rab 11隔室。在富含C18-SM的细胞中，VacA主要与耐洗涤剂膜（DRM）相关，但在富含C2-SM的细胞中主要与非DRM相关。这些结果表明，SM是必需的靶向VacA膜筏重要的后续Cdc 42依赖的胞饮细胞进入。
P>Plasma membrane sphingomyelin (SM) binds the Helicobacter pylori vacuolating toxin (VacA) to the surface of epithelial cells. To evaluate the importance of SM for VacA cellular entry, we characterized toxin uptake and trafficking within cells enriched with synthetic variants of SM, whose intracellular trafficking properties are strictly dependent on the acyl chain lengths of their sphingolipid backbones. While toxin binding to the surface of cells was independent of acyl chain length, cells enriched with 12- or 18-carbon acyl chain variants of SM (e.g. C12-SM or C18-SM) were more sensitive to VacA, as indicated by toxin-induced cellular vacuolation, than those enriched with shorter 2- or 6-carbon variants (e.g. C2-SM or C6-SM). In C18-SM-enriched cells, VacA was taken into cells by a previously described Cdc42-dependent pinocytic mechanism, localized initially to GPI-enriched vesicles, and ultimately trafficked to Rab7/Lamp1 compartments. In contrast, within C2-SM-enriched cells, VacA was taken up at a slower rate by a Cdc42-independent mechanism and trafficked to Rab11 compartments. VacA-associated predominantly with detergent-resistant membranes (DRMs) in cells enriched with C18-SM, but predominantly with non-DRMs in C2-SM-enriched cells. These results suggest that SM is required for targeting VacA to membrane rafts important for subsequent Cdc42-dependent pinocytic cellular entry.