Promotion of Salmonella typhimurium adherence and membrane ruffling in MDCK epithelia by staurosporine.

Infection of Madin-Darby canine kidney epithelial cell monolayers with Salmonella typhimurium SL1344 for 60 min results in widespread bacterial invasion which is associated with remodelling of the apical cell membrane to form "membrane ruffles'. Treatment of Madin-Darby canine kidney cell monolayers with the protein kinase inhibitor staurosporine resulted in a 12-fold increase in the number of adhered bacteria without significantly affecting bacterial invasion. Staurosporine treatment also significantly increased both the number and size of membrane ruffles. As S. typhimurium adhere preferentially to these areas of membrane lacking microvilli, the increased extent of membrane ruffling may explain the increased bacterial adherence. These data provide evidence that the propagation of membrane ruffles during S. typhimurium infection is modulated by changes in the phosphorylation state of host proteins.