Browse
Submit Data
Databases
API
Help

Dataset Information

6 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

Membrane bound monomer of Staphylococcal alpha-hemolysin induces caspase activation and apoptotic cell death despite initiation of membrane repair pathway.

ABSTRACT:

Background

Wild type Staphylococcal alpha-hemolysin (alpha-HL) assembly on target mammalian cells usually results in necrotic form of cell death; however, caspase activation also occurs. The pathways of caspase activation due to binding/partial assembly by alpha-HL are unknown till date.

Results

Cells treated with H35N (a mutant of alpha-HL that remains as membrane bound monomer), have been shown to accumulate hypodiploid nuclei, activate caspases and induce intrinsic mitochondrial apoptotic pathway. We have earlier shown that the binding and assembly of alpha-HL requires functional form of Caveolin-1 which is an integral part of caveolae. In this report, we show that the caveolae of mammalian cells, which undergo a continuous cycle of 'kiss and run' dynamics with the plasma membrane, have become immobile upon the binding of the monomer. The cells treated with H35N were unable to recover despite activation of membrane repair mechanism involving caspase-1 dependent activation of sterol regulatory element binding protein-1.

Conclusions

This is for the first time we show the range of cellular changes and responses that take place immediately after the binding of the monomeric form of staphylococcal alpha-hemolysin.

SUBMITTER: Srivastava SS

PROVIDER: S-EPMC2708924 | biostudies-literature |

REPOSITORIES: biostudies-literature

ACCESS DATA

Json Xml

Similar Datasets

Translocating kilobase RNA through the Staphylococcal α-hemolysin nanopore.

Project description:The electrophoretic translocation of polynucleotides through nanopores may permit direct single-molecule nucleic acid sequencing. Here we describe the translocation of ssRNA heteropolymers (91-6083 bases) through the α-hemolysin nanopore. Translocation of these long ssRNAs is characterized by surprisingly long, almost complete ionic current blockades with durations averaging milliseconds per base (at +180 mV). The event durations decrease exponentially with increased transmembrane potential but are largely unaffected by the presence of urea. When the ssRNA is coupled at the 3' end to streptavidin, which cannot translocate through the pore, permanent blockades are observed, supporting our conclusion that the transient blockades arise from ssRNA translocation.

| S-EPMC3712197 | biostudies-literature

Plant plasma membrane-bound staphylococcal-like DNases as a novel class of eukaryotic nucleases.

Project description:BackgroundThe activity of degradative nucleases responsible for genomic DNA digestion has been observed in all kingdoms of life. It is believed that the main function of DNA degradation occurring during plant programmed cell death is redistribution of nucleic acid derived products such as nitrogen, phosphorus and nucleotide bases. Plant degradative nucleases that have been studied so far belong mainly to the S1-type family and were identified in cellular compartments containing nucleic acids or in the organelles where they are stored before final application. However, the explanation of how degraded DNA components are exported from the dying cells for further reutilization remains open.ResultsBioinformatic and experimental data presented in this paper indicate that two Arabidopsis staphylococcal-like nucleases, named CAN1 and CAN2, are anchored to the cell membrane via N-terminal myristoylation and palmitoylation modifications. Both proteins possess a unique hybrid structure in their catalytic domain consisting of staphylococcal nuclease-like and tRNA synthetase anticodon binding-like motifs. They are neutral, Ca2+-dependent nucleaces showing a different specificity toward the ssDNA, dsDNA and RNA substrates. A study of microarray experiments and endogenous nuclease activity revealed that expression of CAN1 gene correlates with different forms of programmed cell death, while the CAN2 gene is constitutively expressed.ConclusionsIn this paper we present evidence showing that two plant staphylococcal-like nucleases belong to a new, as yet unidentified class of eukaryotic nucleases, characterized by unique plasma membrane localization. The identification of this class of nucleases indicates that plant cells possess additional, so far uncharacterized, mechanisms responsible for DNA and RNA degradation. The potential functions of these nucleases in relation to their unique intracellular location are discussed.

| S-EPMC3505149 | biostudies-literature

Redirecting Pore Assembly of Staphylococcal α-Hemolysin by Protein Engineering.

Project description:α-Hemolysin (αHL), a β-barrel pore-forming toxin (βPFT), is secreted as a water-soluble monomer by Staphylococcus aureus. Upon binding to receptors on target cell membranes, αHL assembles to form heptameric membrane-spanning pores. We have previously engineered αHL to create a protease-activatable toxin that is activated by site-specific proteolysis including by tumor proteases. In this study, we redesigned αHL so that it requires 2-fold activation on target cells through (i) binding to specific receptors, and (ii) extracellular proteolytic cleavage. To assess our strategy, we constructed a fusion protein of αHL with galectin-1 (αHLG1, αHL-Galectin-1 chimera). αHLG1 was cytolytic toward cells that lack a receptor for wild-type αHL. We then constructed protease-activatable mutants of αHLG1 (PAMαHLG1s). PAMαHLG1s were activated by matrix metalloproteinase 2 (MMP-2) and had approximately 50-fold higher cytolytic activity toward MMP-2 overexpressing cells (HT-1080 cells) than toward non-overexpressing cells (HL-60 cells). Our approach provides a novel strategy for tailoring pore-forming toxins for therapeutic applications.

| S-EPMC6487460 | biostudies-literature

Preliminary X-ray crystallographic study of staphylococcal ?-haemolysin monomer.

Project description:Staphylococcal ?-haemolysin is a ?-barrel pore-forming toxin expressed by Staphylococcus aureus. ?-Haemolysin is secreted as a water-soluble monomeric protein which binds to target membranes and forms membrane-inserted heptameric pores. Although the crystal structures of the heptameric pore and monomer bound to an antibody have been determined, that of monomeric ?-haemolysin without binder has yet to be elucidated. Previous mutation studies showed that mutants of His35 retain the monomeric structure but are unable to assemble into heptamers. Here, ?-haemolysin H35A mutants were expressed, purified and crystallized. Diffraction data were collected to 2.90 Å resolution. The crystals belonged to space group P6?, with unit-cell parameters a = b = 151.3, c = 145.0 Å. Molecular replacement found four molecules in an asymmetric unit. The relative orientation among molecules was distinct from that of the pore, indicating that the crystal contained monomeric ?-haemolysin.

| S-EPMC3729161 | biostudies-literature

Translatome and transcriptome profiling of SH-SY5Y cells treated with staphylococcal alpha-hemolysin oligomers

2015-04-01 | GSE60543 | GEO

Yeast Membrane Bound Polysome

Project description:Set of arrays organized by shared biological context, such as organism, tumors types, processes, etc. mRNA species bound to membrane-associated polysomes were separated from other mRNAs by sedimentation equilibrium or sedimentation velocity. The distribution of individual transcripts in the 'membrane-bound' and 'cytosolic' fractions was quantitated for thousands of genes by hybridization to DNA microarrays. Transcripts known to encode secreted or membrane proteins were enriched in the membrane-bound fractions, whereas those known to encode cytoplasmic proteins were enriched in the fractions containing mRNAs associated with free and cytoplasmic ribosomes. On this basis, we identified over 275 human genes and 285 yeast genes that are likely to encode previously unrecognized secreted or membrane proteins. Computed

2005-08-24 | E-GEOD-3180 | biostudies-arrayexpress

Translatome and transcriptome profiling of SH-SY5Y cells treated with staphylococcal alpha-hemolysin oligomers

Project description:Genome-wide analysis of translation has the potential to provide major contributions in understanding the pathophysiology of infection processes, given the complex interplay between pathogens and host cells. This study uncovers the reshaping undergoing in the translational control system of the host in response to staphylococcal α-hemolysin oligomers (rAHL). Keywords: translatome profiling, polysomal profiling, polysomal RNA, translational control, translational profiling, polysome profiling, post-transcriptional regulation, staphylococcal α-hemolysin, pore forming toxins, PTF. The comparison between translatome and transcriptome profiling was used to discover mRNA-specific changes of the SH-SY5Y cells transcriptome and translatome in response to staphylococcal α-hemolysin oligomers (rAHL). To identify translationally regulated mRNAs, gene expression signals derived from the polysomal mRNA populations were compared by microarrays analysis to those obtained from total RNAs. Polysomal mRNA and total mRNA were isolated from SH-SY5Y cells treated with 3nM of extracted oligomers (rAHL) for 2 hours. Cells lysates were collected from untreated cells (control) and from treated cells. All experiments were run in biological triplicates.

2015-04-01 | E-GEOD-60543 | biostudies-arrayexpress

Yeast Membrane Bound Polysome

2005-08-24 | GSE3180 | GEO

2-Methyl-2,4-pentanediol induces spontaneous assembly of staphylococcal ?-hemolysin into heptameric pore structure.

Project description:Staphylococcal ?-hemolysin is expressed as a water-soluble monomeric protein and assembles on membranes to form a heptameric pore structure. The heptameric pore structure of ?-hemolysin can be prepared from monomer in vitro only in the presence of deoxycholate detergent micelles, artificially constructed phospholipid bilayers, or erythrocytes. Here, we succeeded in preparing crystals of the heptameric form of ?-hemolysin without any detergent but with 2-methyl-2,4-pentanediol (MPD), and determined its structure. The structure of the heptameric pore was similar to that reported previously. In the structure, two molecules of MPD were bound around Trp179, around which phospholipid head groups were bound in the heptameric pore structure reported previously. Size exclusion chromatography showed that ?-hemolysin did not assemble spontaneously even when stored for 1 year. SDS-PAGE analysis revealed that, among the compounds in the crystallizing buffer, MPD could induce heptamer formation. The concentration of MPD that most efficiently induced oligomerization was between 10 and 30%. Based on these observations, we propose MPD as a reagent that can facilitate heptameric pore formation of ?-hemolysin without membrane binding.

| S-EPMC3048429 | biostudies-literature

Translatome and transcriptome profiling of SH-SY5Y cells treated with sublytic doses of staphylococcal alpha-hemolysin

Project description:Genome-wide analysis of translation has the potential to provide major contributions in understanding the pathophysiology of infection processes, given the complex interplay between pathogens and host cells. Informations about the translational state of mRNAs or the activity of RNA binding proteins and ncRNAs after treatment with sublytic doses of pore forming toxins are completely missing. This study uncovers the reshaping undergoing in the translational control system of the host in response to sublytic doses of staphylococcal α-hemolysin (AHL). Keywords: translatome profiling, polysomal profiling, polysomal RNA, translational control, translational profiling, polysome profiling, post-transcriptional regulation, staphylococcal α-hemolysin, pore forming toxins, PTF.

2015-04-01 | GSE50652 | GEO

OmicsDI is part of the ELIXIR infrastructure

OmicsDI is an Elixir interoperability service. Learn more ›

Tweets

OmicsDI Databases

PRIDE
PeptideAtlas
MassIVE
JPOST Repository
Physiome Model Repository

EGA
EVA
ENA
LINCS
PAXDB
Cell Collective

MetaboLights
Metabolomics Workbench
MetabolomeExpress
GNPS
BioModels
FAIRDOMHub

ArrayExpress
dbGaP
ExpressionAtlas
GEO
NODE

Information

Databases
Help
API
Contact us
Code on GitHub
Terms of use
Submit Data