Prehna Gerd, Ivanov Maya I, Bliska James B, Stebbins C Erec
Laboratory of Structural Microbiology, Rockefeller University, New York, NY 10021, USA.
Cell. 2006 Sep 8;126(5):869-80. doi: 10.1016/j.cell.2006.06.056.
Yersinia spp. cause gastroenteritis and the plague, representing historically devastating pathogens that are currently an important biodefense and antibiotic resistance concern. A critical virulence determinant is the Yersinia protein kinase A, or YpkA, a multidomain protein that disrupts the eukaryotic actin cytoskeleton. Here we solve the crystal structure of a YpkA-Rac1 complex and find that YpkA possesses a Rac1 binding domain that mimics host guanidine nucleotide dissociation inhibitors (GDIs) of the Rho GTPases. YpkA inhibits nucleotide exchange in Rac1 and RhoA, and mutations that disrupt the YpkA-GTPase interface abolish this activity in vitro and impair in vivo YpkA-induced cytoskeletal disruption. In cell culture experiments, the kinase and the GDI domains of YpkA act synergistically to promote cytoskeletal disruption, and a Y. pseudotuberculosis mutant lacking YpkA GDI activity shows attenuated virulence in a mouse infection assay. We conclude that virulence in Yersinia depends strongly upon mimicry of host GDI proteins by YpkA.
耶尔森氏菌属会引发肠胃炎和鼠疫，它们是历史上极具破坏性的病原体，目前也是生物防御和抗生素耐药性方面的重要关注点。一个关键的毒力决定因素是耶尔森氏菌蛋白激酶A（YpkA），它是一种多结构域蛋白，可破坏真核肌动蛋白细胞骨架。在此，我们解析了YpkA-Rac1复合物的晶体结构，发现YpkA拥有一个Rac1结合结构域，该结构域模拟了Rho GTP酶的宿主鸟苷核苷酸解离抑制剂（GDI）。YpkA抑制Rac1和RhoA中的核苷酸交换，破坏YpkA-GTP酶界面的突变在体外消除了这种活性，并损害了体内YpkA诱导的细胞骨架破坏。在细胞培养实验中，YpkA的激酶结构域和GDI结构域协同作用以促进细胞骨架破坏，并且缺乏YpkA GDI活性的假结核耶尔森氏菌突变体在小鼠感染试验中显示出毒力减弱。我们得出结论，耶尔森氏菌的毒力在很大程度上取决于YpkA对宿主GDI蛋白的模拟。
