Dataset Information

Bilayer-mediated clustering and functional interaction of MscL channels.

ABSTRACT: Mechanosensitive channels allow bacteria to respond to osmotic stress by opening a nanometer-sized pore in the cellular membrane. Although the underlying mechanism has been thoroughly studied on the basis of individual channels, the behavior of channel ensembles has yet to be elucidated. This work reveals that mechanosensitive channels of large conductance (MscL) exhibit a tendency to spatially cluster, and demonstrates the functional relevance of clustering. We evaluated the spatial distribution of channels in a lipid bilayer using patch-clamp electrophysiology, fluorescence and atomic force microscopy, and neutron scattering and reflection techniques, coupled with mathematical modeling of the mechanics of a membrane crowded with proteins. The results indicate that MscL forms clusters under a wide range of conditions. MscL is closely packed within each cluster but is still active and mechanosensitive. However, the channel activity is modulated by the presence of neighboring proteins, indicating membrane-mediated protein-protein interactions. Collectively, these results suggest that MscL self-assembly into channel clusters plays an osmoregulatory functional role in the membrane.

SUBMITTER: Grage SL

PROVIDER: S-EPMC3043215 | biostudies-literature | 2011 Mar

REPOSITORIES: biostudies-literature

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Bilayer-mediated clustering and functional interaction of MscL channels.

Grage Stephan L SL Keleshian Asbed M AM Turdzeladze Tamta T Battle Andrew R AR Tay Wee C WC May Roland P RP Holt Stephen A SA Contera Sonia Antoranz SA Haertlein Michael M Moulin Martine M Pal Prithwish P Rohde Paul R PR Forsyth V Trevor VT Watts Anthony A Huang Kerwyn Casey KC Ulrich Anne S AS Martinac Boris B

Biophysical journal 20110301 5

Mechanosensitive channels allow bacteria to respond to osmotic stress by opening a nanometer-sized pore in the cellular membrane. Although the underlying mechanism has been thoroughly studied on the basis of individual channels, the behavior of channel ensembles has yet to be elucidated. This work reveals that mechanosensitive channels of large conductance (MscL) exhibit a tendency to spatially cluster, and demonstrates the functional relevance of clustering. We evaluated the spatial distributio ...[more]

PMID: 21354398

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Project description:Actinobacillus pleuropneumoniae is an important respiratory pathogen that can cause porcine contagious pleuropneumonia (PCP), resulting in significant economic losses in swine industry. Microorganisms are subjected to drastic changes in environmental osmolarity. In order to alleviate the drastic rise or fall of osmolarity, cells activate mechanosensitive channels MscL and MscS through tension changes. MscL not only regulates osmotic pressure but also has been reported to secrete protein and uptake aminoglycoside antibiotic. However, MscL and MscS, as the most common mechanosensitive channels, have not been characterized in A. pleuropneumoniae. In this study, the osmotic shock assay showed that MscL increased sodium adaptation by regulating cell length. The results of MIC showed that deletion of mscL decreased the sensitivity of A. pleuropneumoniae to multiple antibiotics, while deletion of mscS rendered A. pleuropneumoniae hypersensitive to penicillin. Biofilm assay demonstrated that MscL contributed the biofilm formation but MscS did not. The results of animal assay showed that MscL and MscS did not affect virulence in vivo. In conclusion, MscL is essential for sodium hyperosmotic tolerance, biofilm formation, and resistance to chloramphenicol, erythromycin, penicillin, and oxacillin. On the other hand, MscS is only involved in oxacillin resistance.IMPORTANCEBacterial resistance to the external environment is a critical function that ensures the normal growth of bacteria. MscL and MscS play crucial roles in responding to changes in both external and internal environments. However, the function of MscL and MscS in Actinobacillus pleuropneumoniae has not yet been reported. Our study shows that MscL plays a significant role in osmotic adaptation, antibiotic resistance, and biofilm formation of A. pleuropneumoniae, while MscS only plays a role in antibiotic resistance. Our findings provide new insights into the functional characteristics of MscL and MscS in A. pleuropneumoniae. MscL and MscS play a role in antibiotic resistance and contribute to the development of antibiotics for A. pleuropneumoniae.

Dataset Information

Bilayer-mediated clustering and functional interaction of MscL channels.

Publications

Bilayer-mediated clustering and functional interaction of MscL channels.

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