Microbiology 2002, 148:113–122.PubMed Authors’ contributions LNC carried out the molecular and genetic studies, conducted the 2 D gel electrophoresis studies and drafted the manuscript. RL performed all mass spec studies and protein identifications and reviewed the manuscript. JOL contributed financially to the research and also participated in the manuscript review. YMK conceived the study, participated in its design and coordination and selleck compound helped to draft the manuscript. All authors read and approved the final draft for submission.”
“Background

Pathogenic bacteria of the genus Bordetella produce dermonecrotic toxin (DNT), which activates Rho GTPases through its transglutaminase activity resulting RO4929097 nmr in deamidation or polyamination [1–3]. DNT is a single chain polypeptide of 1,464 amino acids, with an N-terminal region of at least 54 amino acids responsible for binding to a receptor on target cells [4] and a C-terminal region of about 300 amino acids conferring the transglutaminase activity [5]. The receptor for DNT is still unknown. The activated Rho GTPases cause aberrant Rho-dependent phenotypes [6, 7], which likely lead to some of the pathological changes observed during Bordetella infections. For example, the turbinate atrophy in atrophic rhinitis, a Bordetella

infection of pigs, is caused by DNT acting on osteoblastic cells [8–13]. However, there has been no evidence that DNT is actively secreted from the bacteria, and less than 0.75% (0.60 ng/109 CFU) of produced

DNT was detected in culture supernatant of B. bronchiseptica and B. pertussis (unpublished data). It is unknown how this small amount of DNT exerts toxicity against target cells Niclosamide such as osteoblasts covered by epithelial cells and connective tissue. While attempting to identify the receptor for DNT, we found that DNT associated temporarily with fibronectin (FN)-based extracellular matrix (ECM), on both DNT-sensitive and insensitive cells, indicating that the FN network does not serve as a functional receptor for DNT. We hypothesized that the FN network functions as a temporary storage system for DNT, enabling the small amount of the toxin to effectively reach target cells across the epithelia and connective tissue. Results DNT binds to the FN-based ECM network While attempting to identify a receptor for DNT, we found that DNT was distributed along with a fibrillar structure on the surface of MC3T3-E1 cells (Fig. 1A), suggesting an affinity for some selleckchem component of the ECM. This affinity appeared to be dependent on pH: most of the bound toxin was easily washed away from the cell surface at pH 7 or 9, whereas a detectable amount of DNT remained bound after washing at pH 5 (Fig. 1B).