title: Characterization of BCAM0224, a multifunctional trimeric autotransporter from the human pathogen Burkholderia cenocepacia.
abstract: Members of the trimeric autotransporter adhesin (TAA) family play a crucial role in adhesion of Gram-negative pathogens to host cells. Moreover, these proteins are multifunctional virulence factors involved in several other biological traits, including invasion into host cells and evasion of the host immune system. In cystic fibrosis epidemic Burkholderia cenocepacia strain J2315, we identified a unique TAA (BCAM0224)-encoding gene, previously described as being implicated in virulence. Here, we characterized this multifunctional protein, trying to establish its role in B. cenocepacia pathogenicity. We show that BCAM0224 occurs on the bacterial surface and adopts a trimeric conformation. Furthermore, we demonstrated that BCAM0224 is needed for earlier stages of biofilm formation and is required for swarming motility. In addition, BCAM0224 plays an important role in evasion of the human innate immune system, providing resistance against the bactericidal activity of serum via the complement classical pathway. Finally, BCAM0224 mediates bacterial adhesion to and invasion of cultured human bronchial epithelial cells. Together, these data reveal the high versatility of the BCAM0224 protein as a virulence factor in the pathogenic bacterium B. cenocepacia.
authors.affiliation: IBB-Institute for Biotechnology and Bioengineering, Instituto Superior Técnico, Lisbon, Portugal.
authors.forename: Dalila
authors.initials: D
authors.lastname: Mil-Homens
authors.forename: Maria Inês
authors.initials: MI
authors.lastname: Leça
authors.forename: Fábio
authors.initials: F
authors.lastname: Fernandes
authors.forename: Sandra N
authors.initials: SN
authors.lastname: Pinto
authors.forename: Arsenio M
authors.initials: AM
authors.lastname: Fialho
mesh_terms: D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D057508:Burkholderia cenocepacia / Q000235:genetics / Q000378:metabolism*; D002460:Cell Line; D015964:Gene Expression Regulation, Bacterial / Q000502:physiology; D006801:Humans; D008958:Models, Molecular; D008969:Molecular Sequence Data; D011487:Protein Conformation; D017434:Protein Structure, Tertiary; D037521:Virulence Factors
chemical_list: D001426:Bacterial Proteins; D037521:Virulence Factors