Cyclic AMP-regulated exocytosis of Escherichia coli from infected bladder epithelial cells.

The superficial bladder epithelium is a powerful barrier to urine and also serves as a regulator of bladder volume, which is achieved by apical exocytosis of specialized fusiform vesicles during distension of the bladder. We report that type 1 fimbriated uropathogenic Escherichia coli (UPEC) circumvents the bladder barrier by harboring in these Rab27b/CD63-positive and cAMP-regulatable fusiform vesicles within bladder epithelial cells (BECs). Incorporation of UPEC into BEC fusiform compartments enabled bacteria to escape elimination during voiding and to re-emerge in the urine as the bladder distended.

Pseudomonas invasion of type I pneumocytes is dependent on the expression and phosphorylation of caveolin-2.

Pseudomonas aeruginosa is a major cause of pneumonia in patients with cystic fibrosis and other immuncompromising conditions. Here we showed that P. aeruginosa invades type I pneumocytes via a lipid raft-mediated mechanism.