Identification and characterization of VopT, a novel ADP-ribosyltransferase effector protein secreted via the Vibrio parahaemolyticus type III secretion system 2
Identification and characterization of VopT, a novel ADP-ribosyltransferase effector protein secreted via the Vibrio parahaemolyticus type III secretion system 2
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DOI：
10.1111/j.1462-5822.2007.00980.x
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发表时间：
2007-11-01
影响因子：
3.4
通讯作者：
Honda, Takeshi
中科院分区：
文献类型：
--
作者：
Kodama, Toshio;Rokuda, Mitsuhiro;Honda, Takeshi
副溶血性弧菌菌株RIMD 2210633具有两组编码两个独立的III型分泌系统（T3 SS）的基因，称为T3 SS 1和T3 SS 2。T3 SS 2在肠毒性中起作用，仅存在于对人类致病的神奈川现象阳性菌株中。因此，T3 SS 2被认为与副溶血性弧菌人类致病性密切相关。尽管如此，T3 SS 2的生物学作用和由该系统分泌的效应蛋白的身份尚未得到很好的理解。在这里，我们报告T3 SS 2诱导Caco-2和HCT-8细胞的细胞毒性作用。此外，据透露，VPA 1327（vopT），T3 SS 2附近编码的基因，是这种细胞毒性作用的部分原因。VopT分别与ExoT和ExoS的ADP-核糖基转移酶（ADPRT）结构域显示出约45%和44%的同一性，ExoT和ExoS是铜绿假单胞菌分泌的两种T3 SS效应子。发现T3 SS 2不仅是分泌所必需的，而且是VopT易位到宿主细胞中所必需的。我们还表明，VopT ADP-核糖基化Ras，低分子量G（LMWG）蛋白的成员在体内和体外。这些结果表明VopT是通过副溶血性弧菌T3 SS分泌的新型ADPRT效应子。
Vibrio parahaemolyticus strain RIMD2210633 has two sets of genes encoding two separate type III secretion systems (T3SSs), called T3SS1 and T3SS2. T3SS2 has a role in enterotoxicity and is present only in Kanagawa phenomenon-positive strains, which are pathogenic to humans. Accordingly, T3SS2 is considered to be closely related to V. parahaemolyticus human pathogenicity. Despite this, the biological actions of T3SS2 and the identity of the effector protein(s) secreted by this system have not been well understood. Here we report that T3SS2 induces a cytotoxic effect in Caco-2 and HCT-8 cells. Moreover, it was revealed that VPA1327 (vopT), a gene encoded within the proximity of T3SS2, is partly responsible for this cytotoxic effect. The VopT shows approximately 45% and 44% identity with the ADP-ribosyltransferase (ADPRT) domain of ExoT and ExoS, respectively, which are two T3SS-secreted effectors of Pseudomonas aeruginosa. T3SS2 was found to be necessary not only for the secretion, but also for the translocation of the VopT into host cells. We also demonstrate that VopT ADP-ribosylates Ras, a member of the low-molecular-weight G (LMWG) proteins both in vivo and in vitro. These results indicate that VopT is a novel ADPRT effector secreted via V. parahaemolyticus T3SS.