Figure 8.

Occludin is hyperphosphorylated on threonine and translocates into the cytoplasm. We analyzed the solubility of occludin as an indication of its association with tight junctions. Protein lysates in the form of X-100 Triton soluble (S) and insoluble (I) fractions were obtained from Caco2 cell monolayers after infection with wild-type S. Typhi, CVD 908-htrA, and CVD 909 for 4 and 22 h. Equal amounts were loaded on the gel, electrophoresed, transferred onto a membrane and blotted with antibodies. (A) Western blot of protein samples blotted with anti-occludin (upper panel), anti-phosphothreonine (middle panel), and anti-actin (lower panel) as loading control, 4 h following exposure to bacteria. (B,C) Quantification of the data shown in (A). (D) Western blot of protein samples blotted with anti-occludin (upper panel), anti-phosphothreonine (middle panel) and anti-actin (lower panel) 22 h post-infection with S. Typhi strains. (E,F). Quantification of the data shown in (D). Data have been normalized to the actin loading control. These results represent the average of two individual experiments.