In vivo characterization of the scaffold activity of flotillin on the membrane kinase KinC of Bacillus subtilis

Schneider, Johannes; Mielich-Süss, Benjamin; Böhme, Richard; López, Daniel

doi:10.1099/mic.0.000137

Cited by 30 publications

(29 citation statements)

References 85 publications

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“…The FMMs of B. subtilis contain two different flotillin-like scaffold proteins, FloA and FloT, that homo- and hetero-oligomerize. FloT is the larger protein (509 aa compared to 331 aa) and has an extended C-terminal region 31,32,61 (Fig. 1a and Supp.…”

Section: Resultsmentioning

confidence: 99%

The Bacterial Cytoskeleton Spatially Confines Functional Membrane Microdomains

Machta

et al. 2020

Preprint

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22Cell membranes laterally segregate into microdomains enriched in certain lipids and scaffold 23 proteins. Membrane microdomains modulate protein-protein interactions and are essential for cell 24 polarity, signaling and membrane trafficking. How cells organize their membrane microdomains, and 25 the physiological importance of these microdomains, is unknown. In eukaryotes, the cortical actin 26 cytoskeleton is proposed to act like a fence, constraining the dynamics of membrane microdomains. 27Like their eukaryotic counterparts, bacterial cells have functional membrane microdomains (FMMs) 28 that act as platforms for the efficient oligomerization of protein complexes. In this work, we used the 29 model organism Bacillus subtilis to demonstrate that FMM organization and movement depend 30 primarily on the interaction of FMM scaffold proteins with the domains' protein cargo, rather than with 31 domain lipids. Additionally, the MreB actin-like cytoskeletal network that underlies the bacterial 32 membrane was found to frame areas of the membrane in which FMM mobility is concentrated. 33Variations in membrane fluidity did not affect FMM mobility whereas alterations in cell wall organization 34 affected FMM mobility substantially. Interference with MreB organization alleviates FMM spatial 35 confinement whereas, by contrast, inhibition of cell wall synthesis strengthens FMM confinement. The 36 restriction of FMM lateral mobility by the submembranous actin-like cytoskeleton or the extracellular 37 wall cytoskeleton appears to be a conserved mechanism in prokaryotic and eukaryotic cells for 38 localizing functional protein complexes in specific membrane regions, thus contributing to the 39 organization of cellular processes. 40 41 42 43 48 actually heterogeneous fluids, with different membrane lipid species laterally segregating into sub-49 micrometer domains, driven by their physico-chemical properties 2-4 . This heterogeneous organization 50 of membrane lipids leads to a heterogeneous distribution of the embedded membrane proteins, which 51 appears essential for their functionality 5 . Membrane microdomains are widely present, mobile 52 structures that vary in size from transient protein clusters measured in nm 6 to large micron-sized stable 53 domains such as desmosomes 7 . These domains harbor proteins specialized in membrane trafficking, 54 cell-cell adhesion, and signal transduction, and they provide targets for viral entry 8 . 56It is now appreciated that membrane proteins can significantly impact membrane organization, in 57 particular stabilizing membrane domains. For instance, the scaffold activity of the flotillin proteins FLO1 58 and FLO2 plays an important role in stabilizing some eukaryotic membrane rafts ("lipid rafts") 9-11 ; it 59 would seem that this raft organization occurs in part through the capture and stabilization of specific 60 lipids by flotillins 12,13 . In addition, the activity of the flotillin scaffold contributes to the recruitment of 61 other raft-associated proteins, thus facilitatin...

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Section: Resultsmentioning

confidence: 99%

The Bacterial Cytoskeleton Spatially Confines Functional Membrane Microdomains

Machta

et al. 2020

Preprint

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“…Surfactins act as a signaling molecule selectively induce potassium leakage and known to stimulate biofilm formation upon membrane disturbance and KinC perception (López et al ., ). Recently, it has also been described that the membrane‐associated chaperone protein, flotillin (FloT) embedded in the membrane micro‐domains of Bacillus , interact with KinC to promote effective binding of specific‐signaling proteins (Schneider et al ., ). Also host related factors might modulate biofilm formation (Beauregard et al ., ) and related histidine kinases, particularly KinD, seem to be involved in sensing products released by plant roots (Chen et al ., ).…”

Section: Discussionmentioning

confidence: 99%

Surfactin variants mediate species‐specific biofilm formation and root colonization in Bacillus

Aleti

Lehner

Bacher

et al. 2016

Environmental Microbiology

106

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Cyclic lipopeptides (cLP) and especially surfactins produced by Bacillus spp. trigger biofilm formation and root colonization and are crucial for biocontrol activity and systemic resistance in plants. Bacillus atrophaeus 176s isolated from the moss Tortella tortuosa produces the cLP fengycins, iturins and surfactins, possesses antifungal activities and can protect tomato, lettuce and sugar beet against Rhizoctonia solani infection. In B. atrophaeus we identified for the first time the variant surfactin C, which differs from surfactin A produced by B. subtilis and B. amyloliquefaciens by an isoleucine instead of a leucine at position 7 of the lipopeptide backbone. The analysis of the complete surfactin gene clusters revealed that the dissimilarity is encoded in the adenylation domain of srfC and show that surfactin variations are distributed in a species-specific manner in bacilli. We demonstrate that the surfactin A and C with subtle structural differences have varying signal strengths on biofilm formation and root colonization and act specifically on the respective producing strain. This became evident as biofilm formation and root colonization but not swarming motility in surfactin biosynthesis mutants was restored differentially in the presence of exogenously supplemented cognate and non-cognate surfactin variants.

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“…Membrane isolation was adapted from 54 . Briefly, cells were grown until an OD600 of 0.4 - 0.5, cell fractions were collected and resuspended in PBS with Lysozyme (1 µg.ml −1 ), EDTA (5 mM), 1/10 tablet cOmplete protease inhibitor (Roche), and DNAse (5 µg.ml −1 ) and incubated for 30 min on ice.…”

Section: Methodsmentioning

confidence: 99%

Flotillin mediated membrane fluidity controls peptidoglycan synthesis and MreB movement

Zielińska

Savietto

Borges

et al. 2019

Preprint

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20The bacterial plasma membrane is an important cellular compartment. In recent years 21 it has become obvious that protein complexes and lipids are not uniformly distributed 22 within membranes. Current hypotheses suggest that flotillin proteins are required for the 23 formation of complexes of membrane proteins including cell-wall synthetic proteins. We 24show here that bacterial flotillins are important factors for membrane fluidity 25 homeostasis. Loss of flotillins leads to a decrease in membrane fluidity that in turn leads 26to alterations in MreB dynamics and, as a consequence, in peptidoglycan synthesis. These 27 alterations are reverted when membrane fluidity is restored by a chemical fluidizer. In 28 sufficient to convert spherical cells to a rod shape 8,9 . In Bacillus subtilis, the motion of MreB 54 along the membrane is associated with elongasome activity 10,11 and the velocity of MreB 55 patches is related to growth rate 12 , indicating that MreB motion can be used as a marker for 56 elongasome activity. Interestingly, MreB localizes to and organizes regions of increased 57 membrane fluidity (RIF) 13 , which in turn is linked to the presence of LipidII, which favours a 58 more fluid membrane and promotes local membrane disorder 14,15 . Inhibition of LipidII 59 synthesis by genetic or chemical means results in a dissolution of membrane structures 60 observed with the dye FM 4-64 and release of MreB from the membrane 10,11,16,17 . 61Next to RIFs, membrane regions of decreased fluidity have been identified in bacteria 7,18,19 . 62

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In vivo characterization of the scaffold activity of flotillin on the membrane kinase KinC of Bacillus subtilis

Cited by 30 publications

References 85 publications

The Bacterial Cytoskeleton Spatially Confines Functional Membrane Microdomains

The Bacterial Cytoskeleton Spatially Confines Functional Membrane Microdomains

Surfactin variants mediate species‐specific biofilm formation and root colonization in Bacillus

Flotillin mediated membrane fluidity controls peptidoglycan synthesis and MreB movement

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