Molecular Dynamics Study of Lipid and Cholesterol Reorganization Due to Membrane Binding and Pore Formation by Listeriolysin O

Cheerla, Ramesh; Ayappa, K. G.

doi:10.1007/s00232-020-00148-9

Cited by 20 publications

(29 citation statements)

References 81 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…As well as the OlyA6/PlyB pores in the LUVs, free OlyA6/PlyB oligomers could be seen in the solution. While oligomerisation and pore formation at the concentrations used for these experiments required the presence of membranes to concentrate the proteins, it is not unusual for the oligomers to be in solution after oligomerisation, which appears to occur after oligomer formation and shedding from the membranes [35,36]. The efficient binding to these CPE-containing artificial membranes prompted us to investigate the formation of OlyA6/PlyB hetero-oligomers on LUVs reconstituted from the non-polar lipids extracted from the WCR larvae.…”

Section: Cryo-electron Microscopy Of the Olya6/plyb Assembly On Large Unilamellar Vesicles And Brush Border Membrane Vesiclesmentioning

confidence: 99%

Dissecting Out the Molecular Mechanism of Insecticidal Activity of Ostreolysin A6/Pleurotolysin B Complexes on Western Corn Rootworm

Jotić

Panevska

Iacovache

et al. 2021

Toxins

View full text Add to dashboard Cite

Ostreolysin A6 (OlyA6) is a protein produced by the oyster mushroom (Pleurotus ostreatus). It binds to membrane sphingomyelin/cholesterol domains, and together with its protein partner, pleurotolysin B (PlyB), it forms 13-meric transmembrane pore complexes. Further, OlyA6 binds 1000 times more strongly to the insect-specific membrane sphingolipid, ceramide phosphoethanolamine (CPE). In concert with PlyB, OlyA6 has potent and selective insecticidal activity against the western corn rootworm. We analysed the histological alterations of the midgut wall columnar epithelium of western corn rootworm larvae fed with OlyA6/PlyB, which showed vacuolisation of the cell cytoplasm, swelling of the apical cell surface into the gut lumen, and delamination of the basal lamina underlying the epithelium. Additionally, cryo-electron microscopy was used to explore the membrane interactions of the OlyA6/PlyB complex using lipid vesicles composed of artificial lipids containing CPE, and western corn rootworm brush border membrane vesicles. Multimeric transmembrane pores were formed in both vesicle preparations, similar to those described for sphingomyelin/cholesterol membranes. These results strongly suggest that the molecular mechanism of insecticidal action of OlyA6/PlyB arises from specific interactions of OlyA6 with CPE, and the consequent formation of transmembrane pores in the insect midgut.

show abstract

Section: Cryo-electron Microscopy Of the Olya6/plyb Assembly On Large Unilamellar Vesicles And Brush Border Membrane Vesiclesmentioning

confidence: 99%

Dissecting Out the Molecular Mechanism of Insecticidal Activity of Ostreolysin A6/Pleurotolysin B Complexes on Western Corn Rootworm

Jotić

Panevska

Iacovache

et al. 2021

Toxins

View full text Add to dashboard Cite

show abstract

“…In this regime, the 2-state model predicts a preponderance of arcs (Fig. 3) and recent molecular dynamics simulations reveal that arc-like states have a tendency to protrude outward from the membrane plane when compared with the fully formed ring-like pore states (21, 47) We note that the regime of low values of C p ( < 1 nM) lies outside the purview of the two-state model, where LLO is more likely to sample membrane bound non-inserted states.…”

Section: Resultsmentioning

confidence: 83%

Bacterial pore-forming proteins induce non-monotonic dynamics due to lipid ejection and crowding

Ponmalar

Ayappa

Basu

2020

Preprint

View full text Add to dashboard Cite

Developing alternate strategies against pore forming toxin (PFT) mediated bacterial virulence factors require an understanding of the target cellular response to combat rising antimicrobial resistance. Membrane-bound protein complexes involving PFTs, released by virulent bacteria are known to form pores leading to host cell lysis. However, membrane disruption and related lipid mediated active repair processes during attack by PFTs remain largely unexplored. We report counter intuitive and non-monotonic variations in lipid diffusion, measured using confocal fluorescence correlation spectroscopy, due to interplay of lipid ejection and crowding by membrane bound oligomers of a prototypical cholesterol dependent cytolysin, Listeriolysin O (LLO). The observed protein concentration dependent dynamical cross-over is correlated with transitions of LLO oligomeric state populations from rings to arc-like pore complexes, predicted using a proposed two-state free area based diffusion model. At low PFT concentrations, a hitherto unexplored regime of increased lipid diffusivity is attributed to lipid ejection events due to a preponderance of ring-like pore states. At higher protein concentrations where membrane inserted arc-like pores dominate, lipid ejection is less efficient and the ensuing crowding results in a lowering of lipid diffusion. These variations in lipid dynamics are corroborated by macroscopic rheological response measurements of PFT bound vesicles. Our study correlates PFT oligomeric state transitions, membrane remodelling and mechanical property variations, providing unique insights into developing strategies to combat virulent bacterial pathogens responsible for several infectious diseases.SIGNIFICANCEDeveloping alternate strategies against pore forming toxin (PFT) mediated bacterial virulence factors requires understanding target cellular responses and cellular defence strategies to combat rising antimicrobial resistant strains. While it is well understood that PFTs exist in a wide variety of oligomeric states, the underlying membrane response to these states is unexplored. Using confocal fluorescence correlation spectroscopy and a membrane free area based model we relate non-monotonic variations in the lipid diffusivity arising from an interplay of lipid ejection events and membrane crowding due to variations in concentration of membrane bound listeriolysin O. Our observations have a direct bearing on understanding cellular defense and repair mechanisms effective during initial stages of bacterial infection and intrinsically connected to the underlying membrane fluidity.

show abstract

“…Crystal structure of SLO ( 42 ), PLY ( 49 ), and listeriolysin (LLO) ( 50 ). Indicated are N-terminus, C-terminus, and four domains rich in β-sheets: Domain 1 (D1), Domain 2 (D2), Domain 3 (D3) with the transmembrane spanning region, and Domain 4 (D4) involved in the initial direct interaction with cholesterol and glycans ( 51 – 53 ). The molecular weights and protein data bank (PDB) codes are also indicated.…”

Section: Cdcsmentioning

confidence: 99%

“…A recent study ( 51 ) showed that four D4 subunits of LLO in the membrane-bound state are placed in the bilayer interface in a pre-pore configuration. In contrast, the membrane-inserted state consists of a tetrameric arc-like pore configuration.…”

Section: Cdc Interactions With Mast Cellsmentioning

confidence: 99%

Molecular Mechanisms of Mast Cell Activation by Cholesterol-Dependent Cytolysins

2021

View full text Add to dashboard Cite

Mast cells are potent immune sensors of the tissue microenvironment. Within seconds of activation, they release various preformed biologically active products and initiate the process of de novo synthesis of cytokines, chemokines, and other inflammatory mediators. This process is regulated at multiple levels. Besides the extensively studied IgE and IgG receptors, toll-like receptors, MRGPR, and other protein receptor signaling pathways, there is a critical activation pathway based on cholesterol-dependent, pore-forming cytolytic exotoxins produced by Gram-positive bacterial pathogens. This pathway is initiated by binding the exotoxins to the cholesterol-rich membrane, followed by their dimerization, multimerization, pre-pore formation, and pore formation. At low sublytic concentrations, the exotoxins induce mast cell activation, including degranulation, intracellular calcium concentration changes, and transcriptional activation, resulting in production of cytokines and other inflammatory mediators. Higher toxin concentrations lead to cell death. Similar activation events are observed when mast cells are exposed to sublytic concentrations of saponins or some other compounds interfering with the membrane integrity. We review the molecular mechanisms of mast cell activation by pore-forming bacterial exotoxins, and other compounds inducing cholesterol-dependent plasma membrane perturbations. We discuss the importance of these signaling pathways in innate and acquired immunity.

show abstract

Molecular Dynamics Study of Lipid and Cholesterol Reorganization Due to Membrane Binding and Pore Formation by Listeriolysin O

Cited by 20 publications

References 81 publications

Dissecting Out the Molecular Mechanism of Insecticidal Activity of Ostreolysin A6/Pleurotolysin B Complexes on Western Corn Rootworm

Dissecting Out the Molecular Mechanism of Insecticidal Activity of Ostreolysin A6/Pleurotolysin B Complexes on Western Corn Rootworm

Bacterial pore-forming proteins induce non-monotonic dynamics due to lipid ejection and crowding

Molecular Mechanisms of Mast Cell Activation by Cholesterol-Dependent Cytolysins

Contact Info

Product

Resources

About