Host cell-surface proteins as substrates of gingipains, the main proteases of Porphyromonas gingivalis

2018 ◽  
Vol 399 (12) ◽  
pp. 1353-1361 ◽  
Author(s):  
Katarina Hočevar ◽  
Jan Potempa ◽  
Boris Turk
Keyword(s):  
Cell Surface ◽  
Host Cell ◽  
Signaling Pathways ◽  
Porphyromonas Gingivalis ◽  
Cysteine Proteases ◽  
Surface Proteins ◽  
Published Data ◽  
Tissue Destruction ◽  
Cell Surface Proteins ◽  
Host Cell Surface

Abstract Gingipains are extracellular cysteine proteases of the oral pathogen Porphyromonas gingivalis and are its most potent virulence factors. They can degrade a great variety of host proteins, thereby helping the bacterium to evade the host immune response, deregulate signaling pathways, trigger anoikis and, finally, cause tissue destruction. Host cell-surface proteins targeted by gingipains are the main focus of this review and span three groups of substrates: immune-regulatory proteins, signaling pathways regulators and adhesion molecules. The analysis of published data revealed that gingipains predominantly inactivate their substrates by cleaving them at one or more sites, or through complete degradation. Sometimes, gingipains were even found to initially shed their membrane substrates, but this was mostly just the first step in the degradation of cell-surface proteins.

scholarly journals Differential potential for envelope glycoprotein-mediated steric shielding of host cell surface proteins among filoviruses

Virology ◽  
2013 ◽  
Vol 446 (1-2) ◽  
pp. 152-161 ◽  
Author(s):  
Osamu Noyori ◽  
Keita Matsuno ◽  
Masahiro Kajihara ◽  
Eri Nakayama ◽  
Manabu Igarashi ◽  
...  
Keyword(s):  
Cell Surface ◽  
Host Cell ◽  
Envelope Glycoprotein ◽  
Surface Proteins ◽  
Cell Surface Proteins ◽  
Host Cell Surface

scholarly journals Cholesterol and host cell surface proteins contribute to cell-cell fusion induced by the Burkholderia type VI secretion system 5

PLoS ONE ◽  
2017 ◽  
Vol 12 (10) ◽  
pp. e0185715 ◽  
Author(s):  
Liam Whiteley ◽  
Maria Haug ◽  
Kristina Klein ◽  
Matthias Willmann ◽  
Erwin Bohn ◽  
...  
Keyword(s):  
Cell Surface ◽  
Host Cell ◽  
Cell Fusion ◽  
Secretion System ◽  
Surface Proteins ◽  
Type Vi Secretion System ◽  
Cell Surface Proteins ◽  
Type Vi Secretion ◽  
Host Cell Surface ◽  
Cell Cell

scholarly journals The Diverse Contributions of Fucose Linkages in Cancer

Cancers ◽  
2019 ◽  
Vol 11 (9) ◽  
pp. 1241 ◽  
Author(s):  
Tyler S. Keeley ◽  
Shengyu Yang ◽  
Eric Lau
Keyword(s):  
Cell Surface ◽  
Signaling Pathways ◽  
Cancer Biology ◽  
Surface Proteins ◽  
Biological Processes ◽  
Post Translational Modification ◽  
Therapeutic Approaches ◽  
Cell Surface Proteins ◽  
Clinical Diagnostic

Fucosylation is a post-translational modification of glycans, proteins, and lipids that is responsible for many biological processes. Fucose conjugation via α(1,2), α(1,3), α(1,4), α(1,6), and O’- linkages to glycans, and variations in fucosylation linkages, has important implications for cancer biology. This review focuses on the roles that fucosylation plays in cancer, specifically through modulation of cell surface proteins and signaling pathways. How L-fucose and serum fucosylation patterns might be used for future clinical diagnostic, prognostic, and therapeutic approaches will be discussed.

scholarly journals The Distinct Immune-Stimulatory Capacities of Porphyromonas gingivalis Strains 381 and ATCC 33277 Are Determined by the fimB Allele and Gingipain Activity

2019 ◽  
Vol 87 (12) ◽  
Author(s):  
Stephen R. Coats ◽  
Nutthapong Kantrong ◽  
Thao T. To ◽  
Sumita Jain ◽  
Caroline A. Genco ◽  
...  
Keyword(s):  
Cell Surface ◽  
Immune Responses ◽  
Host Cell ◽  
Porphyromonas Gingivalis ◽  
Stop Codon ◽  
Premature Stop Codon ◽  
Innate Immune ◽  
Surface Proteins ◽  
Innate Immune Responses ◽  
Content Type

ABSTRACT The Porphyromonas gingivalis strain ATCC 33277 (33277) and 381 genomes are nearly identical. However, strain 33277 displays a significantly diminished capacity to stimulate host cell Toll-like receptor 2 (TLR2)-dependent signaling and interleukin-1β (IL-1β) production relative to 381, suggesting that there are strain-specific differences in one or more bacterial immune-modulatory factors. Genomic sequencing identified a single nucleotide polymorphism in the 33277 fimB allele (A→T), creating a premature stop codon in the 33277 fimB open reading frame relative to the 381 fimB allele. Gene exchange experiments established that the 33277 fimB allele reduces the immune-stimulatory capacity of this strain. Transcriptome comparisons revealed that multiple genes related to carboxy-terminal domain (CTD) family proteins, including the gingipains, were upregulated in 33277 relative to 381. A gingipain substrate degradation assay demonstrated that cell surface gingipain activity is higher in 33277, and an isogenic mutant strain deficient for the gingipains exhibited an increased ability to induce TLR2 signaling and IL-1β production. Furthermore, 33277 and 381 mutant strains lacking CTD cell surface proteins were more immune-stimulatory than the parental wild-type strains, consistent with an immune-suppressive role for the gingipains. Our data show that the combination of an intact fimB allele and limited cell surface gingipain activity in P. gingivalis 381 renders this strain more immune-stimulatory. Conversely, a defective fimB allele and high-level cell surface gingipain activity reduce the capacity of P. gingivalis 33277 to stimulate host cell innate immune responses. In summary, genomic and transcriptomic comparisons identified key virulence characteristics that confer divergent host cell innate immune responses to these highly related P. gingivalis strains.

Isolation and partial characterization of host cell surface agglutinin and its role in attachment of a biotrophic mycoparasite

1991 ◽  
Vol 37 (5) ◽  
pp. 377-383 ◽  
Author(s):  
M. S. Manocha ◽  
Y. Chen
Keyword(s):  
Cell Surface ◽  
Host Cell ◽  
Polyacrylamide Gel Electrophoresis ◽  
Sodium Dodecyl ◽  
Surface Proteins ◽  
Carbohydrate Binding ◽  
Protein Extract ◽  
Host Cell Wall ◽  
Host Cell Surface ◽  
Faint Band

Cell surface proteins obtained by alkaline extraction from isolated cell walls of Mortierella pusilla and M. candelabrum, host and nonhost, respectively, of the mycoparasite Piptocephalis virginiana, were tested for their ability to agglutinate mycoparasite spores. The host cell wall protein extract had a high agglutinating activity (788 agglutination units/mg) compared with that of the nonhost extract (21 agglutination units/mg). Sodium dodecyl sulfate – polyacrylamide gel electrophoresis of the crude extract of the host revealed four bands, a, b, c, and d, with respective Mr of 117 000, 100 000, 85 000 and 64 000; these bands except for a faint band c, were absent from the nonhost surface. Deletion of proteins b or c from the crude protein extract of the host significantly reduced its agglutinating activity. Proteins b and c, purified by a series of procedures, were shown to be glycoproteins with glucose and N-acetylglucosamine as major saccharides. The agglutinating activity of a mixture of pure proteins b and c was over 500 times that of either glycoprotein alone, suggesting an involvement of both glycoproteins in the agglutination process. Further characterization showed that the two glycoproteins were heat-resistant with respect to their agglutinin function, which could be totally inhibited by three sugars: arabinose, glucose and N-acetyglucosamine. It is suggested that glycoproteins b and c are the two subunits of a carbohydrate-binding agglutinin present at the host cell surface and involved in agglutination and attachment of the mycoparasite germ tubes. Key words: agglutinin, attachment, cell surface, sugars, glycoproteins, mycoparasitism.

scholarly journals Tetraspanins Associated With oxLDL and IgG Mediated Phagocytosis In Human U937 Macrophages

2021 ◽  
Author(s):  
Pardis Pakshir
Keyword(s):  
Cell Surface ◽  
Signaling Pathways ◽  
Laser Scanning ◽  
Laser Scanning Confocal Microscopy ◽  
Fc Receptor ◽  
Surface Proteins ◽  
Specific Cell ◽  
Cell Surface Proteins ◽  
Scanning Confocal Microscopy ◽  
Receptor Complexes

One of the crucial key targets in treatment of diseases are cell surface proteins, such as receptor complexes, and their associated signaling pathways. The Fc receptor is one of the most important phagocytic receptors of the cells of immune system. The ligand of the Fc gamma receptor is immunoglobulin G (IgG), which triggers the engulfment of foreign molecules coated by antibodies by a process called phagocytosis. A Specialized subset of cells including macrophages engulfs foreign particles by the Fc receptor. Another phagocytic receptor of macrophages is the CD36 receptor, which binds the ligand oxLDL and is known to be involved in the development of atherosclerotic lesions in the arteries. A few members of the Tetraspanin proteins have been found to be associated with theses receptors in macrophages. Tetraspanins may act as “molecular facilitators” grouping specific cell-surface proteins and thus increasing the formation and stability of functional signaling complexes. There is a significant amount of research done on the receptors of the surface of macrophages, however, the proteins associated with these receptors, their potential signaling pathways and the mechanisms involved are not yet fully understood. This thesis aims to investigate the presence and potential functional role of the specific Tetraspanin isoforms in Fc and CD36 mediated phagocytosis. Silencing RNA, quantitative assays of phagocytosis, and laser scanning confocal microscopy were used to test the phagocytic efficiency of macrophages in IgG and oxLDL mediated phagocytosis. Understanding the regulatory roles of Tetraspanins can provide insight into various immune diseases.

scholarly journals Tetraspanins Associated With oxLDL and IgG Mediated Phagocytosis In Human U937 Macrophages

2021 ◽  
Author(s):  
Pardis Pakshir
Keyword(s):  
Cell Surface ◽  
Signaling Pathways ◽  
Laser Scanning ◽  
Laser Scanning Confocal Microscopy ◽  
Fc Receptor ◽  
Surface Proteins ◽  
Specific Cell ◽  
Cell Surface Proteins ◽  
Scanning Confocal Microscopy ◽  
Receptor Complexes

One of the crucial key targets in treatment of diseases are cell surface proteins, such as receptor complexes, and their associated signaling pathways. The Fc receptor is one of the most important phagocytic receptors of the cells of immune system. The ligand of the Fc gamma receptor is immunoglobulin G (IgG), which triggers the engulfment of foreign molecules coated by antibodies by a process called phagocytosis. A Specialized subset of cells including macrophages engulfs foreign particles by the Fc receptor. Another phagocytic receptor of macrophages is the CD36 receptor, which binds the ligand oxLDL and is known to be involved in the development of atherosclerotic lesions in the arteries. A few members of the Tetraspanin proteins have been found to be associated with theses receptors in macrophages. Tetraspanins may act as “molecular facilitators” grouping specific cell-surface proteins and thus increasing the formation and stability of functional signaling complexes. There is a significant amount of research done on the receptors of the surface of macrophages, however, the proteins associated with these receptors, their potential signaling pathways and the mechanisms involved are not yet fully understood. This thesis aims to investigate the presence and potential functional role of the specific Tetraspanin isoforms in Fc and CD36 mediated phagocytosis. Silencing RNA, quantitative assays of phagocytosis, and laser scanning confocal microscopy were used to test the phagocytic efficiency of macrophages in IgG and oxLDL mediated phagocytosis. Understanding the regulatory roles of Tetraspanins can provide insight into various immune diseases.

What do nanometer molecular trajectories tell us about heterogeneous cell surface domaines?

1995 ◽  
Vol 53 ◽  
pp. 786-787
Author(s):  
Watt W. Webb
Keyword(s):  
Cell Surface ◽  
Lipid Membranes ◽  
Surface Proteins ◽  
Protein Diffusion ◽  
Coated Pits ◽  
Cell Surface Proteins ◽  
Membrane Heterogeneity ◽  
Fluorescence Photobleaching Recovery ◽  
Photobleaching Recovery ◽  
Plasma Membrane Heterogeneity

Plasma membrane heterogeneity is implicit in the existence of specialized cell surface organelles which are necessary for cellular function; coated pits, post and pre-synaptic terminals, microvillae, caveolae, tight junctions, focal contacts and endothelial polarization are examples. The persistence of these discrete molecular aggregates depends on localized restraint of the constituent molecules within specific domaines in the cell surface by strong intermolecular bonds and/or anchorage to extended cytoskeleton. The observed plasticity of many of organelles and the dynamical modulation of domaines induced by cellular signaling evidence evanescent intermolecular interactions even in conspicuous aggregates. There is also strong evidence that universal restraints on the mobility of cell surface proteins persist virtually everywhere in cell surfaces, not only in the discrete organelles. Diffusion of cell surface proteins is slowed by several orders of magnitude relative to corresponding protein diffusion coefficients in isolated lipid membranes as has been determined by various ensemble average methods of measurement such as fluorescence photobleaching recovery(FPR).

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