scholarly journals N-Acetylglucosamine Functions in Cell Signaling

Scientifica ◽  
2012 ◽  
Vol 2012 ◽  
pp. 1-15 ◽  
Author(s):  
James B. Konopka
Keyword(s):  
Cell Wall ◽  
Cell Surface ◽  
Cell Signaling ◽  
Amino Sugar ◽  
Animal Cells ◽  
Fungal Cell ◽  
E Coli ◽  
Human Fungal Pathogen ◽  
Surface Signaling ◽  
Cell Surface Signaling

The amino sugar N-acetylglucosamine (GlcNAc) is well known for the important structural roles that it plays at the cell surface. It is a key component of bacterial cell wall peptidoglycan, fungal cell wall chitin, and the extracellular matrix of animal cells. Interestingly, recent studies have also identified new roles for GlcNAc in cell signaling. For example, GlcNAc stimulates the human fungal pathogenCandida albicansto undergo changes in morphogenesis and expression of virulence genes. PathogenicE. coliresponds to GlcNAc by altering the expression of fimbriae and CURLI fibers that promote biofilm formation and GlcNAc stimulates soil bacteria to undergo changes in morphogenesis and production of antibiotics. Studies with animal cells have revealed that GlcNAc influences cell signaling through the posttranslational modification of proteins by glycosylation. O-linked attachment of GlcNAc to Ser and Thr residues regulates a variety of intracellular proteins, including transcription factors such as NFκB, c-myc, and p53. In addition, the specificity of Notch family receptors for different ligands is altered by GlcNAc attachment to fucose residues in the extracellular domain. GlcNAc also impacts signal transduction by altering the degree of branching of N-linked glycans, which influences cell surface signaling proteins. These emerging roles of GlcNAc as an activator and mediator of cellular signaling in fungi, animals, and bacteria will be the focus of this paper.

scholarly journals Arabinogalactan Proteins in Plant Roots – An Update on Possible Functions

2021 ◽  
Vol 12 ◽  
Author(s):  
Dagmar Hromadová ◽  
Aleš Soukup ◽  
Edita Tylová
Keyword(s):  
Cell Wall ◽  
Regulatory Networks ◽  
Developmental Plasticity ◽  
Molecular Mechanisms ◽  
Arabinogalactan Proteins ◽  
Cellular Level ◽  
Environmental Response ◽  
Essential Components ◽  
Surface Signaling ◽  
Cell Surface Signaling

Responsiveness to environmental conditions and developmental plasticity of root systems are crucial determinants of plant fitness. These processes are interconnected at a cellular level with cell wall properties and cell surface signaling, which involve arabinogalactan proteins (AGPs) as essential components. AGPs are cell-wall localized glycoproteins, often GPI-anchored, which participate in root functions at many levels. They are involved in cell expansion and differentiation, regulation of root growth, interactions with other organisms, and environmental response. Due to the complexity of cell wall functional and regulatory networks, and despite the large amount of experimental data, the exact molecular mechanisms of AGP-action are still largely unknown. This dynamically evolving field of root biology is summarized in the present review.

scholarly journals N-Acetylglucosamine Regulates Morphogenesis and Virulence Pathways in Fungi

2019 ◽  
Vol 6 (1) ◽  
pp. 8 ◽  
Author(s):  
Kyunghun Min ◽  
Shamoon Naseem ◽  
James B. Konopka
Keyword(s):  
Cell Wall ◽  
Stress Responses ◽  
Hyphal Growth ◽  
Amino Sugar ◽  
Model Organisms ◽  
Animal Cells ◽  
Epigenetic Switch ◽  
Wide Range ◽  
Extracellular Environment

N-acetylglucosamine (GlcNAc) is being increasingly recognized for its ability to stimulate cell signaling. This amino sugar is best known as a component of cell wall peptidoglycan in bacteria, cell wall chitin in fungi and parasites, exoskeletons of arthropods, and the extracellular matrix of animal cells. In addition to these structural roles, GlcNAc is now known to stimulate morphological and stress responses in a wide range of organisms. In fungi, the model organisms Saccharomyces cerevisiae and Schizosaccharomyces pombe lack the ability to respond to GlcNAc or catabolize it, so studies with the human pathogen Candida albicans have been providing new insights into the ability of GlcNAc to stimulate cellular responses. GlcNAc potently induces C. albicans to transition from budding to filamentous hyphal growth. It also promotes an epigenetic switch from White to Opaque cells, which differ in morphology, metabolism, and virulence properties. These studies have led to new discoveries, such as the identification of the first eukaryotic GlcNAc transporter. Other results have shown that GlcNAc can induce signaling in C. albicans in two ways. One is to act as a signaling molecule independent of its catabolism, and the other is that its catabolism can cause the alkalinization of the extracellular environment, which provides an additional stimulus to form hyphae. GlcNAc also induces the expression of virulence genes in the C. albicans, indicating it can influence pathogenesis. Therefore, this review will describe the recent advances in understanding the role of GlcNAc signaling pathways in regulating C. albicans morphogenesis and virulence.

scholarly journals Human tumor-derived exosomes (TEX) regulate Treg functions via cell surface signaling rather than uptake mechanisms

2017 ◽  
Vol 6 (8) ◽  
pp. e1261243 ◽  
Author(s):  
Laurent Muller ◽  
Patricia Simms ◽  
Chang-Sook Hong ◽  
Michael I. Nishimura ◽  
Edwin K. Jackson ◽  
...  
Keyword(s):  
Cell Surface ◽  
Human Tumor ◽  
Surface Signaling ◽  
Cell Surface Signaling ◽  
Uptake Mechanisms

Observing Cell Surface Signaling Domains Using Electron Microscopy

2003 ◽  
Vol 2003 (177) ◽  
pp. pl9-pl9 ◽  
Author(s):  
I. A. Prior ◽  
R. G. Parton ◽  
J. F. Hancock
Keyword(s):  
Electron Microscopy ◽  
Cell Surface ◽  
Surface Signaling ◽  
Cell Surface Signaling ◽  
Signaling Domains

scholarly journals Role of Cell Surface Signaling in Proteolysis of an Alternative Sigma Factor in Pseudomonas aeruginosa

2008 ◽  
Vol 190 (14) ◽  
pp. 4865-4869 ◽  
Author(s):  
Matthew R. Spencer ◽  
Paul A. Beare ◽  
Iain L. Lamont
Keyword(s):  
Cell Surface ◽  
Signaling Pathway ◽  
Sigma Factor ◽  
Receptor Protein ◽  
Proteolytic Degradation ◽  
Alternative Sigma Factor ◽  
A Cell ◽  
Surface Signaling ◽  
Cell Surface Signaling ◽  
Antisigma Factor

ABSTRACT Alternative sigma factor proteins enable transcription of specific sets of genes in bacterial cells. Their activities can be controlled by posttranslational mechanisms including inhibition by antisigma proteins and proteolytic degradation. PvdS is an alternative sigma factor that is required for expression of genes involved in synthesis of a siderophore, pyoverdine, by Pseudomonas aeruginosa. In the absence of pyoverdine, the activity of PvdS is inhibited by a membrane-spanning antisigma factor, FpvR. Inhibition is relieved by a cell surface signaling pathway. In this pathway, a combination of pyoverdine and a cell surface receptor protein, FpvA, suppresses the antisigma activity of FpvR, enabling transcription of PvdS-dependent genes. In this research, we investigated proteolytic degradation of PvdS in response to the signaling pathway. Proteolysis of PvdS was observed in strains of P. aeruginosa in which FpvR had anti-sigma factor activity due to the absence of pyoverdine or the FpvA receptor protein or overproduction of FpvR. Suppression of antisigma activity by addition of pyoverdine or through the absence of FpvR prevented detectable proteolysis of PvdS. The amounts of PvdS were less in bacteria in which proteolysis was observed, and reporter gene assays showed that this reduction was not due to decreased expression of PvdS. In wild-type bacteria, there was an average of 730 molecules of PvdS per cell in late exponential growth phase. Our results show that proteolysis and amounts of PvdS are affected by the antisigma factor FpvR and that this activity of FpvR is controlled by the cell surface signaling pathway.

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