Department of Cell and Molecular Biology, Karolinska Institutet, Box 285, S-171 77 Stockholm, Sweden.
J Cell Sci. 2011 Aug 15;124(Pt 16):2735-42. doi: 10.1242/jcs.085845.
The DNA damage response triggered by bacterial cytolethal distending toxins (CDTs) is associated with activation of the actin-regulating protein RhoA and phosphorylation of the downstream-regulated mitogen-activated protein kinase (MAPK) p38, which promotes the survival of intoxicated (i.e. cells exposed to a bacterial toxin) cells. To identify the effectors of this CDT-induced survival response, we screened a library of 4492 Saccharomyces cerevisiae mutants that carry deletions in nonessential genes for reduced growth following inducible expression of CdtB. We identified 78 genes whose deletion confers hypersensitivity to toxin. Bioinformatics analysis revealed that DNA repair and endocytosis were the two most overrepresented signaling pathways. Among the human orthologs present in our data set, FEN1 and TSG101 regulate DNA repair and endocytosis, respectively, and also share common interacting partners with RhoA. We further demonstrate that FEN1, but not TSG101, regulates cell survival, MAPK p38 phosphorylation, RhoA activation and actin cytoskeleton reorganization in response to DNA damage. Our data reveal a previously unrecognized crosstalk between DNA damage and cytoskeleton dynamics in the regulation of cell survival, and might provide new insights on the role of chronic bacteria infection in carcinogenesis.
细菌细胞致死扩张毒素（CDT）引发的 DNA 损伤反应与肌动蛋白调节蛋白 RhoA 的激活和下游调节丝裂原激活蛋白激酶（MAPK）p38 的磷酸化有关，这促进了中毒细胞（即暴露于细菌毒素的细胞）的存活。为了确定这种 CDT 诱导的存活反应的效应物，我们筛选了一个包含 4492 个酿酒酵母突变体的文库，这些突变体在 CdtB 诱导表达后，由于非必需基因的缺失而导致生长减少。我们鉴定出 78 个基因的缺失赋予了对毒素的敏感性。生物信息学分析表明，DNA 修复和内吞作用是两个最具代表性的信号通路。在我们的数据集中存在的人类直系同源物中，FEN1 和 TSG101 分别调节 DNA 修复和内吞作用，并且还与 RhoA 具有共同的相互作用伙伴。我们进一步证明，FEN1 而非 TSG101 调节细胞存活、MAPK p38 磷酸化、RhoA 激活和肌动蛋白细胞骨架重排以响应 DNA 损伤。我们的数据揭示了 DNA 损伤和细胞骨架动力学之间在调节细胞存活中的以前未被认识的串扰，并且可能为慢性细菌感染在致癌作用中的作用提供新的见解。
