Schwan Carsten, Stecher Bärbel, Tzivelekidis Tina, van Ham Marco, Rohde Manfred, Hardt Wolf-Dietrich, Wehland Jürgen, Aktories Klaus
Institut für Experimentelle und Klinische Pharmakologie und Toxikologie, Albert-Ludwigs-Universität Freiburg, Freiburg, Germany.
PLoS Pathog. 2009 Oct;5(10):e1000626. doi: 10.1371/journal.ppat.1000626. Epub 2009 Oct 16.
Clostridium difficile causes antibiotic-associated diarrhea and pseudomembranous colitis by production of the Rho GTPase-glucosylating toxins A and B. Recently emerging hypervirulent Clostridium difficile strains additionally produce the binary ADP-ribosyltransferase toxin CDT (Clostridium difficile transferase), which ADP-ribosylates actin and inhibits actin polymerization. Thus far, the role of CDT as a virulence factor is not understood. Here we report by using time-lapse- and immunofluorescence microscopy that CDT and other binary actin-ADP-ribosylating toxins, including Clostridium botulinum C2 toxin and Clostridium perfringens iota toxin, induce redistribution of microtubules and formation of long (up to >150 microm) microtubule-based protrusions at the surface of intestinal epithelial cells. The toxins increase the length of decoration of microtubule plus-ends by EB1/3, CLIP-170 and CLIP-115 proteins and cause redistribution of the capture proteins CLASP2 and ACF7 from microtubules at the cell cortex into the cell interior. The CDT-induced microtubule protrusions form a dense meshwork at the cell surface, which wrap and embed bacterial cells, thereby largely increasing the adherence of Clostridia. The study describes a novel type of microtubule structure caused by less efficient microtubule capture and offers a new perspective for the pathogenetic role of CDT and other binary actin-ADP-ribosylating toxins in host-pathogen interactions.
艰难梭菌通过产生Rho GTP酶糖基化毒素A和B引起抗生素相关性腹泻和假膜性结肠炎。最近出现的高毒力艰难梭菌菌株还产生二元ADP核糖基转移酶毒素CDT（艰难梭菌转移酶），该毒素使肌动蛋白ADP核糖基化并抑制肌动蛋白聚合。到目前为止，CDT作为毒力因子的作用尚不清楚。在此我们通过延时和免疫荧光显微镜报告，CDT和其他二元肌动蛋白ADP核糖基化毒素，包括肉毒梭菌C2毒素和产气荚膜梭菌iota毒素，诱导微管重新分布并在肠上皮细胞表面形成长（长达>150微米）的基于微管的突起。这些毒素增加了EB1/3、CLIP-170和CLIP-115蛋白对微管正端的修饰长度，并导致捕获蛋白CLASP2和ACF7从细胞皮层的微管重新分布到细胞内部。CDT诱导的微管突起在细胞表面形成密集网络，包裹并嵌入细菌细胞，从而大大增加梭菌的黏附。该研究描述了一种由效率较低的微管捕获引起的新型微管结构，并为CDT和其他二元肌动蛋白ADP核糖基化毒素在宿主-病原体相互作用中的致病作用提供了新视角。
