The Active Subunit of the Cytolethal Distending Toxin, CdtB, Derived From Both Haemophilus ducreyi and Campylobacter jejuni Exhibits Potent Phosphatidylinositol-3,4,5-Triphosphate Phosphatase Activity.
The Active Subunit of the Cytolethal Distending Toxin, CdtB, Derived From Both Haemophilus ducreyi and Campylobacter jejuni Exhibits Potent Phosphatidylinositol-3,4,5-Triphosphate Phosphatase Activity.
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DOI：
10.3389/fcimb.2021.664221
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发表时间：
2021
影响因子：
5.7
通讯作者：
Shenker BJ
中科院分区：
文献类型：
--
作者：
Huang G;Boesze-Battaglia K;Walker LP;Zekavat A;Schaefer ZP;Blanke SR;Shenker BJ
暴露于伴放线聚集杆菌 (Aa) 细胞致死膨胀毒素 (Cdt) 的人淋巴细胞会经历细胞周期停滞和凋亡。在之前的研究中，我们证明活性 Cdt 亚基 CdtB 是一种有效的磷脂酰肌醇 (PI) 3,4,5-三磷酸磷酸酶。此外，AaCdt 处理的细胞表现出 PI-3 激酶 (PI-3K) 信号传导阻断的证据，其特征是 PIP3、pAkt 和 pGSK3β 水平降低。我们还证明，PI-3K 阻断是 AaCdt 诱导淋巴细胞毒性的必要条件。在这项研究中，我们扩展了我们的观察范围，包括对杜克雷嗜血杆菌 (HdCdt) 和空肠弯曲杆菌 (CjCdt) 的 Cdts 进行评估。我们现在报道，HdCdt 和 CjCdt 的 CdtB 亚基与 AaCdt 类似，表现出有效的 PIP3 磷酸酶活性，并且用这些 Cdt 处理的 Jurkat 细胞表现出 PI-3K 信号传导阻断：pAkt 和 pGSK3β 水平降低。由于非磷酸化 GSK3β 是该激酶的活性形式，因此我们比较了 Cdts 对 GSK3β 活性的依赖性。采用两种GSK3β抑制剂：LY2090314和CHIR99021；两种抑制剂均可阻断 Cdts 诱导细胞周期停滞的能力。我们之前已经证明，AaCdt 会诱导 CDK 抑制剂 p21CIP1/WAF1 的增加，而且，这是毒素通过细胞凋亡诱导细胞死亡的必要条件。我们现在证明 HdCdt 和 CjCdt 也共享此要求。还值得注意的是，p21CIP1/WAF1 并不参与这三种 Cdt 诱导细胞周期停滞的能力。最后，我们证明，与 AaCdt 一样，HdCdt 的毒性依赖于宿主细胞蛋白 cellugyrin（并且可能是 CdtB 的内化）； CjCdt 不依赖于该蛋白质。讨论了这些发现与 Cdt 分子作用模式相关的含义。
Human lymphocytes exposed to Aggregatibacter actinomycetemcomitans (Aa) cytolethal distending toxin (Cdt) undergo cell cycle arrest and apoptosis. In previous studies, we demonstrated that the active Cdt subunit, CdtB, is a potent phosphatidylinositol (PI) 3,4,5-triphosphate phosphatase. Moreover, AaCdt-treated cells exhibit evidence of PI-3-kinase (PI-3K) signaling blockade characterized by reduced levels of PIP3, pAkt, and pGSK3β. We have also demonstrated that PI-3K blockade is a requisite of AaCdt-induced toxicity in lymphocytes. In this study, we extended our observations to include assessment of Cdts from Haemophilus ducreyi (HdCdt) and Campylobacter jejuni (CjCdt). We now report that the CdtB subunit from HdCdt and CjCdt, similar to that of AaCdt, exhibit potent PIP3 phosphatase activity and that Jurkat cells treated with these Cdts exhibit PI-3K signaling blockade: reduced levels of pAkt and pGSK3β. Since non-phosphorylated GSK3β is the active form of this kinase, we compared Cdts for dependence on GSK3β activity. Two GSK3β inhibitors were employed, LY2090314 and CHIR99021; both inhibitors blocked the ability of Cdts to induce cell cycle arrest. We have previously demonstrated that AaCdt induces increases in the CDK inhibitor, p21CIP1/WAF1, and, further, that this was a requisite for toxin-induced cell death via apoptosis. We now demonstrate that HdCdt and CjCdt also share this requirement. It is also noteworthy that p21CIP1/WAF1 was not involved in the ability of the three Cdts to induce cell cycle arrest. Finally, we demonstrate that, like AaCdt, HdCdt is dependent upon the host cell protein, cellugyrin, for its toxicity (and presumably internalization of CdtB); CjCdt was not dependent upon this protein. The implications of these findings as they relate to Cdt’s molecular mode of action are discussed.
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影响因子：
4.8
作者：
Cortes-Bratti, X;Karlsson, C;Frisan, T
通讯作者：
Frisan, T
影响因子：
5.7
作者：
Graillot, Vanessa;Dormoy, Inge;Vignard, Julien
通讯作者：
Vignard, Julien
影响因子：
3.7
作者：
Kang, KH;Kim, WH;Choi, KH
通讯作者：
Choi, KH
影响因子：
5.7
作者：
Boesze-Battaglia K;Alexander D;Dlakić M;Shenker BJ
通讯作者：
Shenker BJ
影响因子：
5.7
作者：
Boesze-Battaglia K;Walker LP;Dhingra A;Kandror K;Tang HY;Shenker BJ
通讯作者：
Shenker BJ