FIG. 4.

Decreased coprecipitation of ZO-1 and actin following C. difficile toxin exposure. Actin (A) and ZO-1 (B) were immunoprecipitated (Ip) from control (lanes C) and TcdB (80 ng/ml for 2 h)-exposed (lanes TcdB) monolayers as detailed in Materials and Methods. Immunoprecipitated proteins were Western blotted with antibodies to ZO-1 or actin. Note the diminished ZO-1 level in actin immunoprecipitates following inactivation of Rho proteins with TcdB (arrow). Conversely, ZO-1 immunoprecipitates were probed with antibodies to ZO-1 and actin. Note the decreased intensity actin band in panel B (arrow). The band representing immunoglobulin G is marked as such (IgG). Representative data from three individual experiments are shown.