title: Calcium causes multimerization of the large adhesin LapF and modulates biofilm formation by Pseudomonas putida.
abstract: LapF is a large secreted protein involved in microcolony formation and biofilm maturation in Pseudomonas putida. Its C-terminal domain shows the characteristics of proteins secreted through a type I secretion system and includes a predicted calcium binding motif. We provide experimental evidence of specific binding of Ca(2+) to the purified C-terminal domain of LapF (CLapF). Calcium promotes the formation of large aggregates, which disappear in the presence of the calcium chelator EGTA. Immunolocalization of LapF also shows the tendency of this protein to accumulate in vivo in certain extracellular regions. These findings, along with results showing that calcium influences biofilm formation, lead us to propose a model in which P. putida cells interact with each other via LapF in a calcium-dependent manner during the development of biofilms.
authors.affiliation: Department of Environmental Protection, Estación Experimental del Zaidín, CSIC, Granada, Spain.
authors.forename: Marta
authors.initials: M
authors.lastname: Martínez-Gil
authors.forename: Diego
authors.initials: D
authors.lastname: Romero
authors.forename: Roberto
authors.initials: R
authors.lastname: Kolter
authors.forename: Manuel
authors.initials: M
authors.lastname: Espinosa-Urgel
mesh_terms: D018829:Adhesins, Bacterial / Q000737:chemistry / Q000378:metabolism*; D001422:Bacterial Adhesion / Q000235:genetics; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D018441:Biofilms / Q000254:growth & development*; D002118:Calcium / Q000378:metabolism*; D004533:Egtazic Acid / Q000737:chemistry; D015964:Gene Expression Regulation, Bacterial; D055503:Protein Multimerization; D016958:Pseudomonas putida / Q000737:chemistry / Q000235:genetics / Q000502:physiology*
chemical_list: D018829:Adhesins, Bacterial; D001426:Bacterial Proteins; D004533:Egtazic Acid; D002118:Calcium