Figure 8.
Premature autoproteolysis affects cytotoxicity. (A) Representative phase contrast microscopy of 3T3 fibroblasts treated with TcdA or TcdB at pH 7 or pH 5 in the absence or presence of IP6/DTT. Cell rounding confirms the successful internalization of the glucosyltransferase domain, which is prohibited by extracellular IP6/DTT-induced cleavage. Scale bars represent 50 μm; (B) Quantification of relative non-glucosylated Rac1 (in relation to GAPDH) by specific antibody (mean ± SD, n = 3). Immunoblots were performed from the samples shown under (A); Representative immunoblots are shown in the inserts above the bars.