Bacterial effector binding to ribosomal protein s3 subverts NF-kappaB function.
Bacterial effector binding to ribosomal protein s3 subverts NF-kappaB function.
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DOI：
10.1371/journal.ppat.1000708
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发表时间：
2009-12
期刊：
影响因子：
6.7
通讯作者：
Hardwidge PR
中科院分区：
文献类型：
--
作者：
Gao X;Wan F;Mateo K;Callegari E;Wang D;Deng W;Puente J;Li F;Chaussee MS;Finlay BB;Lenardo MJ;Hardwidge PR
肠道细菌病原体引发食源性疾病，这造成了巨大的经济和健康负担。肠出血性大肠杆菌（EHEC）通过多种途径传播给人类后会导致严重的血性腹泻，包括受污染的牛肉和蔬菜产品、水，或通过与动物接触。EHEC还会引发一种可能致命的肾脏疾病（溶血性尿毒综合征），目前对此没有有效的治疗或预防方法。EHEC和其他肠道病原体（例如，肠致病性大肠杆菌（EPEC）、沙门氏菌、志贺氏菌、耶尔森氏菌）利用III型分泌系统（T3SS）将毒力蛋白（效应子）注入宿主细胞。虽然已知T3SS效应子会破坏宿主细胞功能以促进腹泻疾病和细菌传播，但在许多情况下，这些效应子与宿主蛋白结合并破坏肠上皮细胞正常功能的机制尚未完全明确。在这项研究中，我们提供的证据表明，大肠杆菌O157:H7的nleH1和nleH2基因编码的T3SS效应子与人核糖体蛋白S3（RPS3）结合，RPS3是活化B细胞的核因子κ -轻链增强子（NF - κB）转录复合物的一个亚基。NleH1和NleH2在细胞质中与RPS3共定位，但不在细胞核中。NleH1和NleH2的N末端区域是与RPS3的N末端结合所必需的。NleH1和NleH2是自磷酸化的丝氨酸/苏氨酸蛋白激酶，但它们与RPS3的结合不依赖于激酶活性。NleH1（而非NleH2）会降低RPS3在细胞核中的含量，而不改变p50或p65 NF - κB亚基，也不影响抑制性NF - κB伴侣蛋白IκBα的磷酸化状态或含量。NleH1抑制了一个依赖RPS3/NF - κB的报告质粒的转录，但不抑制不依赖RPS3的报告基因的转录。相反，NleH2刺激了依赖RPS3的转录以及一个依赖AP - 1的报告基因。我们确定了NleH1的一个区域（N40 - K45），它至少部分负责NleH1对RPS3的抑制活性。从大肠杆菌O157:H7中删除nleH1在一个产志贺毒素大肠杆菌感染的无菌仔猪模型中产生了一种高毒力表型。我们认为NleH可能通过与宿主转录复合物的一个辅因子结合来破坏宿主的先天免疫反应。
活化B细胞的核因子κ -轻链增强子（NF - κB）转录因子复合物在调节对感染的免疫反应中起着至关重要的作用。细菌病原体将效应蛋白注入宿主细胞，通过干扰NF - κB的激活来调节宿主的先天免疫反应。我们发现，大肠杆菌O157:H7，出血性结肠炎的一个重要病因，将一种称为NleH1的效应蛋白注入哺乳动物细胞，它通过一种新的机制抑制NF - κB依赖的转录。NleH1直接与NF - κB的一个亚基，核糖体蛋白S3（RPS3）结合。RPS3的功能之一是在不同刺激下引导p65 NF - κB亚基募集到特定的启动子。NleH1（而非一个密切相关的效应子NleH2）通过降低RPS3在细胞核中的含量来减弱宿主的转录输出。我们的研究结果强调了一种以前未被重视的细菌效应蛋白能够改变宿主细胞功能的机制。
Enteric bacterial pathogens cause food borne disease, which constitutes an enormous economic and health burden. Enterohemorrhagic Escherichia coli (EHEC) causes a severe bloody diarrhea following transmission to humans through various means, including contaminated beef and vegetable products, water, or through contact with animals. EHEC also causes a potentially fatal kidney disease (hemolytic uremic syndrome) for which there is no effective treatment or prophylaxis. EHEC and other enteric pathogens (e.g., enteropathogenic E. coli (EPEC), Salmonella, Shigella, Yersinia) utilize a type III secretion system (T3SS) to inject virulence proteins (effectors) into host cells. While it is known that T3SS effectors subvert host cell function to promote diarrheal disease and bacterial transmission, in many cases, the mechanisms by which these effectors bind to host proteins and disrupt the normal function of intestinal epithelial cells have not been completely characterized. In this study, we present evidence that the E. coli O157:H7 nleH1 and nleH2 genes encode T3SS effectors that bind to the human ribosomal protein S3 (RPS3), a subunit of nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) transcriptional complexes. NleH1 and NleH2 co-localized with RPS3 in the cytoplasm, but not in cell nuclei. The N-terminal region of both NleH1 and NleH2 was required for binding to the N-terminus of RPS3. NleH1 and NleH2 are autophosphorylated Ser/Thr protein kinases, but their binding to RPS3 is independent of kinase activity. NleH1, but not NleH2, reduced the nuclear abundance of RPS3 without altering the p50 or p65 NF-κB subunits or affecting the phosphorylation state or abundance of the inhibitory NF-κB chaperone IκBα NleH1 repressed the transcription of a RPS3/NF-κB-dependent reporter plasmid, but did not inhibit the transcription of RPS3-independent reporters. In contrast, NleH2 stimulated RPS3-dependent transcription, as well as an AP-1-dependent reporter. We identified a region of NleH1 (N40-K45) that is at least partially responsible for the inhibitory activity of NleH1 toward RPS3. Deleting nleH1 from E. coli O157:H7 produced a hypervirulent phenotype in a gnotobiotic piglet model of Shiga toxin-producing E. coli infection. We suggest that NleH may disrupt host innate immune responses by binding to a cofactor of host transcriptional complexes. The nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) transcription factor complex plays an essential role in regulating the immune response to infection. Bacterial pathogens inject effector proteins into host cells to modulate the host innate immune response by interfering with NF-κB activation. We have discovered that Escherichia coli O157:H7, an important cause of hemorrhagic colitis, injects into mammalian cells an effector protein termed NleH1, which inhibits NF-κB-dependent transcription through a novel mechanism. NleH1 binds directly to a subunit of NF-κB, the ribosomal protein S3 (RPS3). One of the functions of RPS3 is to guide the recruitment of the p65 NF-κB subunit to specific promoters in response to different stimuli. NleH1, but not a closely related effector, NleH2, functions by reducing the nuclear abundance of RPS3 to dampen host transcriptional outputs. Our findings highlight a previously unappreciated mechanism by which bacterial effector proteins are able to alter host cell functions.
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影响因子：
30.5
作者：
Arbibe, Laurence;Kim, Dong Wook;Sansonetti, Philippe J.
通讯作者：
Sansonetti, Philippe J.
影响因子：
3.2
作者：
Charpentier, X;Oswald, E
通讯作者：
Oswald, E
影响因子：
4.4
作者：
Baker, Diane R.;Moxley, Rodney A.;Francis, David H.
通讯作者：
Francis, David H.
影响因子：
3.1
作者：
DONNENBERG, MS;KAPER, JB
通讯作者：
KAPER, JB
DOI：
10.1073/pnas.120163297
发表时间：
2000-06-06
影响因子：
11.1
作者：
Datsenko, KA;Wanner, BL
通讯作者：
Wanner, BL