- Paper Report
- Open Access
Tyrosine kinases required for Pseudomonas aeruginosainvasion
- Lori L Burrows1
© Biomed Central Ltd 2001
- Received: 21 February 2001
- Published: 18 September 2001
- CFTR, epithelial cells, invasion, P. aeruginosa, Src-like tyrosine kinases
The mechanism by which Pseudomonas aeruginosa invades host epithelial cells is not known. Other bacterial pathogens have been shown to co-opt the host cells' tyrosine kinase signalling, particularly Src-like tyrosine kinase pathways, probably to induce cytoskeletal remodelling. A previous study by Evans et al (see Additional information) implicated Src tyrosine kinases in P. aeruginosa invasion of corneal epithelium. The specific aim of this study was to demonstrate the role of Src-like tyrosine kinases in P. aeruginosa invasion of human epithelial cells.
Invasion of conjuctival or pulmonary epithelial cells by P. aeruginosa induced rapid, marked tyrosine phosphorylation of several proteins. Phosphorylation of p59Fyn and p60Src was demonstrated to increase fourfold to fivefold within 10 min of infection and to peak within 15-45 min. Tyrosine phosphorylation was specific to invasion of the host cells, and not simply a consequence of generalized bacterial adherence. Preincubation of bacteria with an invasion-specific receptor (cystic fibrosis transmembrane regulator [CFTR]) peptide blocked both invasion and phosphorylation without preventing attachment of bacteria to epithelial cells. The Src-like tyrosine kinase inhibitor compounds herbimycin A and PP1 significantly reduced bacterial entry for all tested bacterial strain/cell type/drug combinations. The authors concluded the following: firstly, both p60Src and p59Fyn are involved in invasion of human epithelial cell lines by P. aeruginosa; secondly, the specific binding of bacteria to CFTR is a prerequisite for invasion; and, thirdly, that tyrosine kinase activation is required for (but not a result of) entry since blocking phosphorylation abrogates internalization of the bacteria.
Cell culture, polymyxin protection assays, phosphotyrosine western blot and immunoprecipitation
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