LapD is a bis-(3',5')-cyclic dimeric GMP-binding protein that regulates surface attachment by Pseudomonas fluorescens Pf0-1

• Published in: Proceedings of the National Academy of Sciences - PNAS Vol. 106; no. 9; pp. 3461 - 3466
• Main Authors: Newell, Peter D, Monds, Russell D, O'Toole, George A
• Format: Journal Article
• Language: English
• Published: United States National Academy of Sciences 03-03-2009; National Acad Sciences
• Subjects: 3',5'-Cyclic-GMP Phosphodiesterases - metabolism; Adhesins, Bacterial - metabolism; Allosteric regulation; Bacteria; Bacterial Adhesion; Bacterial proteins; Binding sites; Biofilms; Biological Sciences; Carrier Proteins - genetics; Carrier Proteins - metabolism; Cyclic GMP - analogs & derivatives; Cyclic GMP - metabolism; Enzyme Activation; Gene expression regulation; Intracellular Signaling Peptides and Proteins - genetics; Intracellular Signaling Peptides and Proteins - metabolism; Mathematical functions; Mutation - genetics; Phenotypes; Physiological regulation; Protein Binding; Protein Multimerization; Pseudomonas fluorescens; Pseudomonas fluorescens - genetics; Pseudomonas fluorescens - metabolism; Receptors; Regulon; Resins; Signal Transduction; Studies
• ISSN: 0027-8424; 1091-6490
• DOI: 10.1073/pnas.0808933106

The second messenger cyclic dimeric GMP (c-di-GMP) regulates surface attachment and biofilm formation by many bacteria. For Pseudomonas fluorescens Pf0-1, c-di-GMP impacts the secretion and localization of the adhesin LapA, which is absolutely required for stable surface attachment and biofilm formation by this bacterium. In this study we characterize LapD, a unique c-di-GMP effector protein that controls biofilm formation by communicating intracellular c-di-GMP levels to the membrane-localized attachment machinery via its periplasmic domain. LapD contains degenerate and enzymatically inactive diguanylate cyclase and c-di-GMP phosphodiesterase (EAL) domains and binds to c-di-GMP through a degenerate EAL domain. We present evidence that LapD utilizes an inside-out signaling mechanism: binding c-di-GMP in the cytoplasm and communicating this signal to the periplasm via its periplasmic domain. Furthermore, we show that LapD serves as the c-di-GMP receptor connecting environmental modulation of intracellular c-di-GMP levels by inorganic phosphate to regulation of LapA localization and thus surface commitment by P. fluorescens.