Evidence for filaggrin as a component of the cell envelope of the newborn rat.
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ABSTRACT:
SUBMITTER: Richards S
PROVIDER: S-EPMC1149269 | biostudies-other | 1988 Jul
REPOSITORIES: biostudies-other
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Project description:Cornified cell envelope (CE) is generated during the late stages of epidermal differentiation and is made up of proteins covalently linked together by transglutaminases. To determine whether filaggrin is a component of this structure in humans, we analysed highly purified CE from plantar stratum corneum. An immunoelectron microscopy analysis showed specific binding of four different anti-(pro)filaggrin monoclonal antibodies to the surface of the CE, proved previously to be free of non-covalently linked proteins. Moreover, the anti-filaggrin activity of one of the antibodies was absorbed by preincubation with the plantar CE, as determined by ELISA. Convincingly, fragments of CE produced by proteolytic digestion of the structures were stained by this antibody on immunoblots. These data provide direct evidence that filaggrin is a component of CE purified from human plantar stratum corneum. Cross-linking between CE and the filaggrin-containing fibrous matrix may enhance the structural cohesion of the corneocytes and thus the resistance of the stratum corneum.
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Project description:To investigate the R. sphaeroides NtrYX two component system on RNA transcript levels, we used global RNA sequencing (RNA-seq) to compare transcript abundance in parent and DntrYX strains grown under aerobic conditions. Our previous studies were performed in strains deficient at synthesizing the polyhydroxybutyrate, so we used strains D0382 and DNtrYXD0382, herein referred to as parent and DntrYX, respectively. We also used ChIP-seq to identify NtrX binding sites throughout the genome.
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Project description:Activity of the NtrYX two-component system has been associated with important processes in diverse bacteria, ranging from symbiosis to nitrogen and energy metabolism. In the facultative alphaproteobacterium Rhodobacter sphaeroides, loss of the two-component system NtrYX results in increased lipid production and sensitivity to some known cell envelope-active compounds. In this study, we show that NtrYX directly controls multiple properties of the cell envelope. We find that the response regulator NtrX binds upstream of cell envelope genes, including those involved in peptidoglycan biosynthesis and modification and in cell division. We show that loss of NtrYX impacts the cellular levels of peptidoglycan precursors and lipopolysaccharide and alters cell envelope structure, increasing cell length and the thickness of the periplasm. Cell envelope function is also disrupted in the absence of NtrYX, resulting in increased outer membrane permeability. Based on the properties of R. sphaeroides cells lacking NtrYX and the target genes under direct control of this two-component system, we propose that NtrYX plays a previously undescribed, and potentially conserved, role in the assembly, structure, and function of the cell envelope in a variety of bacteria.IMPORTANCE The bacterial cell envelope provides many important functions. It protects cells from harsh environments, serves as a selective permeability barrier, houses bioenergetic functions, defines sensitivity to antibacterial agents, and plays a crucial role in biofilm formation, symbiosis, and virulence. Despite the important roles of this cellular compartment, we lack a detailed understanding of the biosynthesis and remodeling of the cell envelope. Here, we report that the R. sphaeroides two-component signaling system NtrYX is a previously undescribed regulator of cell envelope processes, providing evidence that it is directly involved in controlling transcription of genes involved in cell envelope assembly, structure, and function in this and possibly other bacteria. Thus, our data report on a newly discovered process used by bacteria to assemble and remodel the cell envelope.
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2011-05-16 | E-GEOD-27061 | biostudies-arrayexpress
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Project description:Staphylococcus aureus possesses 16 two-component systems (TCSs), two of which (GraRS and NsaRS) belong to the intramembrane-sensing histidine kinase (IM-HK) family, which is conserved within the firmicutes. NsaRS has recently been documented as being important for nisin resistance in S. aureus. In this study, we present a characterization of NsaRS and reveal that, as with other IM-HK TCSs, it responds to disruptions in the cell envelope. Analysis using a lacZ reporter-gene fusion demonstrated that nsaRS expression is upregulated by a variety of cell-envelope-damaging antibiotics, including phosphomycin, ampicillin, nisin, gramicidin, carbonyl cyanide m-chlorophenylhydrazone and penicillin G. Additionally, we reveal that NsaRS regulates a downstream transporter NsaAB during nisin-induced stress. NsaS mutants also display a 200-fold decreased ability to develop resistance to the cell-wall-targeting antibiotic bacitracin. Microarray analysis reveals that the transcription of 245 genes is altered in an nsaS mutant, with the vast majority being downregulated. Included within this list are genes involved in transport, drug resistance, cell envelope synthesis, transcriptional regulation, amino acid metabolism and virulence. Using inductively coupled plasma-MS we observed a decrease in intracellular divalent metal ions in an nsaS mutant when grown under low abundance conditions. Characterization of cells using electron microscopy reveals that nsaS mutants have alterations in cell envelope structure. Finally, a variety of virulence-related phenotypes are impaired in nsaS mutants, including biofilm formation, resistance to killing by human macrophages and survival in whole human blood. Thus, NsaRS is important in sensing cell damage in S. aureus and functions to reprogram gene expression to modify cell envelope architecture, facilitating adaptation and survival.
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Project description:S. aureus possesses 16 two-component systems (TCS), two of which (GraRS & NsaRS) belong to the intramembrane-sensing histidine kinase (IM-HK) family, conserved within the firmicutes. NsaRS has recently been documented as being important for nisin-resistance in S. aureus. In this study we present a detailed characterization of NsaRS and reveal that, as with other IM-HK TCS, it responds to disruptions in cell-wall stability. Analysis using a lacZ reporter-gene fusion demonstrated that nsaRS expression is upregulated by a variety of cell-wall damaging antibiotics, including Phosphomycin, Ampicillin, Nisin and Penicillin G. Additionally; we reveal that NsaRS regulates a downstream transporter, NsaAB, during nisin-induced stress. NsaS mutants also display a 200-fold decreased ability to develop resistance to the cell-wall targetting antibiotic bacitracin. Microarray analysis reveals the transcription of 245 genes is altered in a nsaS mutant, with the vast majority down-regulated. Included within this list are genes involved in transport, drug-resistance, cell-envelope synthesis, transcriptional regulation, amino acid metabolism and virulence. Using ICP-MS we observed a decrease in intracellular divalent metal ions in an nsaS mutant when grown under low affinity conditions. Characterization of cells using electron microscopy reveals that nsaS mutants have alterations in both cell-wall and cell-envelope structure. Finally, a variety of virulence related phenotypes are impaired in nsaS mutants, including biofilm formation, resistance to killing by human macrophages and survival in whole human blood. Thus NsaRS is important in sensing cell-wall instability in S. aureus, and functions to reprogram gene expression to modify cell-envelope architecture, facilitating adaptation and survival.
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