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Contact- and Protein Transfer-Dependent Stimulation of Assembly of the Gliding Motility Machinery in Myxococcus xanthus.

Jakobczak B, Keilberg D, Wuichet K, Søgaard-Andersen L - PLoS Genet. (2015)

Bottom Line: Conversely, incorporation of AglZ and AglQ into the gliding motility complex depends on CglC, GltB, GltA and GltC.Remarkably, physical transfer of the OM lipoprotein CglC to a ΔcglC recipient stimulates assembly of the gliding motility complex in the recipient likely by facilitating the OM integration of GltB and GltA.These data provide evidence that the gliding motility complex in M. xanthus includes OM proteins and suggest that this complex extends from the cytoplasm across the cell envelope to the OM.

View Article: PubMed Central - PubMed

Affiliation: Department of Ecophysiology, Max Planck Institute for Terrestrial Microbiology, Marburg, Germany.

ABSTRACT
Bacteria engage in contact-dependent activities to coordinate cellular activities that aid their survival. Cells of Myxococcus xanthus move over surfaces by means of type IV pili and gliding motility. Upon direct contact, cells physically exchange outer membrane (OM) lipoproteins, and this transfer can rescue motility in mutants lacking lipoproteins required for motility. The mechanism of gliding motility and its stimulation by transferred OM lipoproteins remain poorly characterized. We investigated the function of CglC, GltB, GltA and GltC, all of which are required for gliding. We demonstrate that CglC is an OM lipoprotein, GltB and GltA are integral OM β-barrel proteins, and GltC is a soluble periplasmic protein. GltB and GltA are mutually stabilizing, and both are required to stabilize GltC, whereas CglC accumulate independently of GltB, GltA and GltC. Consistently, purified GltB, GltA and GltC proteins interact in all pair-wise combinations. Using active fluorescently-tagged fusion proteins, we demonstrate that GltB, GltA and GltC are integral components of the gliding motility complex. Incorporation of GltB and GltA into this complex depends on CglC and GltC as well as on the cytoplasmic AglZ protein and the inner membrane protein AglQ, both of which are components of the gliding motility complex. Conversely, incorporation of AglZ and AglQ into the gliding motility complex depends on CglC, GltB, GltA and GltC. Remarkably, physical transfer of the OM lipoprotein CglC to a ΔcglC recipient stimulates assembly of the gliding motility complex in the recipient likely by facilitating the OM integration of GltB and GltA. These data provide evidence that the gliding motility complex in M. xanthus includes OM proteins and suggest that this complex extends from the cytoplasm across the cell envelope to the OM. These data add assembly of gliding motility complexes in M. xanthus to the growing list of contact-dependent activities in bacteria.

No MeSH data available.


AglZ-YFP and AglQ-mCherry incorporation into motility complexes depends on CglC, GltB, GltA and GltC.Cells were treated and analyzed as in Fig 6A. Scale bar, 2μm.
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pgen.1005341.g008: AglZ-YFP and AglQ-mCherry incorporation into motility complexes depends on CglC, GltB, GltA and GltC.Cells were treated and analyzed as in Fig 6A. Scale bar, 2μm.

Mentions: To determine whether the incorporation of AglZ and AglQ into the gliding motility complex also depends on CglC, GltB, GltA and GltC, active AglZ-YFP and AglQ-mCherry fusions were expressed from their native sites in the four individual mutant backgrounds. As reported previously [16], AglZ-YFP localized to multiple clusters along the cell length in the majority of the cells as well as to a cell pole in the WT background (Fig 8). In contrast, in the four mutant backgrounds, AglZ-YFP predominantly formed a single large cluster that localized to a cell pole or somewhere along the cell length. These results were similar to those obtained with AglQ-mCherry, which also localize to multiple clusters along the cell length and a cell pole in the WT background [13] (Fig 8). In the absence of CglC, GltB, GltA or GltC, AglQ-mCherry mostly localized diffusely to the cell periphery as well as in a single cluster at a cell pole in the case of the ΔgltB, ΔgltA and ΔgltC mutants. In all four mutant backgrounds, the two fusion proteins accumulated as in WT (S6 Fig). We conclude that proteins that localize to the periplasm and OM are important for incorporation of AglZ as well as AglQ into the gliding motility complex.


Contact- and Protein Transfer-Dependent Stimulation of Assembly of the Gliding Motility Machinery in Myxococcus xanthus.

Jakobczak B, Keilberg D, Wuichet K, Søgaard-Andersen L - PLoS Genet. (2015)

AglZ-YFP and AglQ-mCherry incorporation into motility complexes depends on CglC, GltB, GltA and GltC.Cells were treated and analyzed as in Fig 6A. Scale bar, 2μm.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4488436&req=5

pgen.1005341.g008: AglZ-YFP and AglQ-mCherry incorporation into motility complexes depends on CglC, GltB, GltA and GltC.Cells were treated and analyzed as in Fig 6A. Scale bar, 2μm.
Mentions: To determine whether the incorporation of AglZ and AglQ into the gliding motility complex also depends on CglC, GltB, GltA and GltC, active AglZ-YFP and AglQ-mCherry fusions were expressed from their native sites in the four individual mutant backgrounds. As reported previously [16], AglZ-YFP localized to multiple clusters along the cell length in the majority of the cells as well as to a cell pole in the WT background (Fig 8). In contrast, in the four mutant backgrounds, AglZ-YFP predominantly formed a single large cluster that localized to a cell pole or somewhere along the cell length. These results were similar to those obtained with AglQ-mCherry, which also localize to multiple clusters along the cell length and a cell pole in the WT background [13] (Fig 8). In the absence of CglC, GltB, GltA or GltC, AglQ-mCherry mostly localized diffusely to the cell periphery as well as in a single cluster at a cell pole in the case of the ΔgltB, ΔgltA and ΔgltC mutants. In all four mutant backgrounds, the two fusion proteins accumulated as in WT (S6 Fig). We conclude that proteins that localize to the periplasm and OM are important for incorporation of AglZ as well as AglQ into the gliding motility complex.

Bottom Line: Conversely, incorporation of AglZ and AglQ into the gliding motility complex depends on CglC, GltB, GltA and GltC.Remarkably, physical transfer of the OM lipoprotein CglC to a ΔcglC recipient stimulates assembly of the gliding motility complex in the recipient likely by facilitating the OM integration of GltB and GltA.These data provide evidence that the gliding motility complex in M. xanthus includes OM proteins and suggest that this complex extends from the cytoplasm across the cell envelope to the OM.

View Article: PubMed Central - PubMed

Affiliation: Department of Ecophysiology, Max Planck Institute for Terrestrial Microbiology, Marburg, Germany.

ABSTRACT
Bacteria engage in contact-dependent activities to coordinate cellular activities that aid their survival. Cells of Myxococcus xanthus move over surfaces by means of type IV pili and gliding motility. Upon direct contact, cells physically exchange outer membrane (OM) lipoproteins, and this transfer can rescue motility in mutants lacking lipoproteins required for motility. The mechanism of gliding motility and its stimulation by transferred OM lipoproteins remain poorly characterized. We investigated the function of CglC, GltB, GltA and GltC, all of which are required for gliding. We demonstrate that CglC is an OM lipoprotein, GltB and GltA are integral OM β-barrel proteins, and GltC is a soluble periplasmic protein. GltB and GltA are mutually stabilizing, and both are required to stabilize GltC, whereas CglC accumulate independently of GltB, GltA and GltC. Consistently, purified GltB, GltA and GltC proteins interact in all pair-wise combinations. Using active fluorescently-tagged fusion proteins, we demonstrate that GltB, GltA and GltC are integral components of the gliding motility complex. Incorporation of GltB and GltA into this complex depends on CglC and GltC as well as on the cytoplasmic AglZ protein and the inner membrane protein AglQ, both of which are components of the gliding motility complex. Conversely, incorporation of AglZ and AglQ into the gliding motility complex depends on CglC, GltB, GltA and GltC. Remarkably, physical transfer of the OM lipoprotein CglC to a ΔcglC recipient stimulates assembly of the gliding motility complex in the recipient likely by facilitating the OM integration of GltB and GltA. These data provide evidence that the gliding motility complex in M. xanthus includes OM proteins and suggest that this complex extends from the cytoplasm across the cell envelope to the OM. These data add assembly of gliding motility complexes in M. xanthus to the growing list of contact-dependent activities in bacteria.

No MeSH data available.