Interaction between the type 4 pili machinery and a diguanylate cyclase fine-tune c-di-GMP levels during early biofilm formation
Autor: | Shanice S. Webster, George A. O'Toole, Calvin K. Lee, Gerard C. L. Wong, William C. Schmidt |
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Rok vydání: | 2021 |
Předmět: |
Mutant
Amino Acid Motifs Motility medicine.disease_cause Models Biological Pilus Type IV Secretion Systems 03 medical and health sciences Bimolecular fluorescence complementation Protein Domains medicine Cyclic GMP Conserved Sequence 030304 developmental biology 0303 health sciences Multidisciplinary biology 030306 microbiology Chemistry Pseudomonas aeruginosa Escherichia coli Proteins Biofilm Biological Sciences biology.organism_classification Cell biology Biofilms Fimbriae Bacterial Mutation biology.protein Diguanylate cyclase Phosphorus-Oxygen Lyases Single-Cell Analysis Bacteria Protein Binding Signal Transduction |
Zdroj: | Proc Natl Acad Sci U S A |
ISSN: | 1091-6490 |
Popis: | To initiate biofilm formation, it is critical for bacteria to sense a surface and respond precisely to activate downstream components of the biofilm program. Type 4 pili (T4P) and increasing levels of c-di-GMP have been shown to be important for surface sensing and biofilm formation, respectively; however, mechanisms important in modulating the levels of this dinucleotide molecule to define a precise output response are unknown. Here, using macroscopic bulk assays and single-cell tracking analyses of Pseudomonas aeruginosa, we uncover a role of the T4P alignment complex protein, PilO, in modulating the activity of the diguanylate cyclase (DGC) SadC. Two-hybrid and bimolecular fluorescence complementation assays, combined with genetic studies, are consistent with a model whereby PilO interacts with SadC and that the PilO-SadC interaction inhibits SadC's activity, resulting in decreased biofilm formation and increased motility. Using single-cell tracking, we monitor both the mean c-di-GMP and the variance of this dinucleotide in individual cells. Mutations that increase PilO-SadC interaction modestly, but significantly, decrease both the average and variance in c-di-GMP levels on a cell-by-cell basis, while mutants that disrupt PilO-SadC interaction increase the mean and variance of c-di-GMP levels. This work is consistent with a model wherein P. aeruginosa uses a component of the T4P scaffold to fine-tune the levels of this dinucleotide signal during surface commitment. Finally, given our previous findings linking SadC to the flagellar machinery, we propose that this DGC acts as a bridge to integrate T4P and flagellar-derived input signals during initial surface engagement. |
Databáze: | OpenAIRE |
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