Lap proteins are a c-di-GMP effector system that controls biofilm in Bordetella bronchiseptica.

AMBROSIS, NICOLÁS; SISTI, FEDERICO; FERNANDEZ, JULIETA

Congreso; L Reunión Anual de la Sociedad Argentina de Investigación en Bioquímica y Biología Molecular; 2014

Bordetella bronchiseptica isa respiratory pathogenic bacterium that forms biofilm-like structures. Previously, we determined that c-di-GMP levels modified ability to form biofilm. However, the bacterial factors involved in biofilm formation has not been yet determined. In Pseudomonas fluorescens a c-di-GMP effectors system controls biofilm formation. LapA is a surface adhesin and its binding to the cell surface is controlled by LapD, in response to c-di-GMP. LapD promotes biofilm formation through LapA accumulation. LapG cleaves LapA, freeing the adhesin and preventing biofilm. Accordingly, when LapG is overexpressed or LapD is absent biofilm is prevented. Homologous to Lap proteins were identified in B. bronchiseptica. When LapGBbwas overexpressed less biofilm was formed on abiotic surfaces. More over, biofilm structures observed by fluorescent microscopy over glass surface and epithelial cells were significantly different. Protruding structures typically observed in wild type biofilms were rarely observed in Bb-LapGBb . To evaluate if LapDBb is involved in biofilm formation, LapDBb gene was deleted. Surprisingly, LapDBb deletion enhanced biofilm formation in B. bronchiseptica. This results showed that although Lap proteins are widespread among gram negative bacteria, their mechanisms may be diverse as LapDBb deletion showed an opposite phenotype than the observed in P. fluorescens.