scholarly journals Binding of Kingella kingae RtxA Toxin Depends on Cell Surface Oligosaccharides, but Not on β2 Integrins

2020 ◽  
Vol 21 (23) ◽  
pp. 9092
Author(s):  
Waheed Ur Rahman ◽  
Adriana Osickova ◽  
Nela Klimova ◽  
Jinery Lora ◽  
Nataliya Balashova ◽  
...  
Keyword(s):  
Cell Surface ◽  
Mammalian Cells ◽  
Mammalian Species ◽  
Cell Types ◽  
Surface Structures ◽  
Target Cells ◽  
Kingella Kingae ◽  
Toxin Binding ◽  
Cell Surface Structures ◽  
Β2 Integrins

The Gram-negative coccobacillus Kingella kingae is increasingly recognized as an important invasive pediatric pathogen that causes mostly bacteremia and skeletal system infections. K. kingae secretes an RtxA toxin that belongs to a broad family of the RTX (Repeats in ToXin) cytotoxins produced by bacterial pathogens. Recently, we demonstrated that membrane cholesterol facilitates interaction of RtxA with target cells, but other cell surface structures potentially involved in toxin binding to cells remain unknown. We show that deglycosylation of cell surface structures by glycosidase treatment, or inhibition of protein N- and O-glycosylation by chemical inhibitors substantially reduces RtxA binding to target cells. Consequently, the deglycosylated cells were more resistant to cytotoxic activity of RtxA. Moreover, experiments on cells expressing or lacking cell surface integrins of the β2 family revealed that, unlike some other cytotoxins of the RTX family, K. kingae RtxA does not bind target cells via the β2 integrins. Our results, hence, show that RtxA binds cell surface oligosaccharides present on all mammalian cells but not the leukocyte-restricted β2 integrins. This explains the previously observed interaction of the toxin with a broad range of cell types of various mammalian species and reveals that RtxA belongs to the group of broadly cytolytic RTX hemolysins.

scholarly journals Cellular Receptors Involved in KSHV Infection

Viruses ◽  
2021 ◽  
Vol 13 (1) ◽  
pp. 118
Author(s):  
Emma van der Meulen ◽  
Meg Anderton ◽  
Melissa J. Blumenthal ◽  
Georgia Schäfer
Keyword(s):  
Virus Infection ◽  
Cell Surface ◽  
Kaposi's Sarcoma ◽  
Kaposi’S Sarcoma ◽  
Cell Types ◽  
Target Cells ◽  
Specific Cell ◽  
Cellular Receptors ◽  
Diverse Range ◽  
Kshv Infection

The process of Kaposi’s Sarcoma Herpes Virus’ (KSHV) entry into target cells is complex and engages several viral glycoproteins which bind to a large range of host cell surface molecules. Receptors for KSHV include heparan sulphate proteoglycans (HSPGs), several integrins and Eph receptors, cystine/glutamate antiporter (xCT) and Dendritic Cell-Specific Intercellular adhesion molecule-3-grabbing non-integrin (DC-SIGN). This diverse range of potential binding and entry sites allows KSHV to have a broad cell tropism, and entry into specific cells is dependent on the available receptor repertoire. Several molecules involved in KSHV entry have been well characterized, particularly those postulated to be associated with KSHV-associated pathologies such as Kaposi’s Sarcoma (KS). In this review, KSHV infection of specific cell types pertinent to its pathogenesis will be comprehensively summarized with a focus on the specific cell surface binding and entry receptors KSHV exploits to gain access to a variety of cell types. Gaps in the current literature regarding understanding interactions between KSHV glycoproteins and cellular receptors in virus infection are identified which will lead to the development of virus infection intervention strategies.

The Role of Cytokines in the Modulation of Cell Surface Antigens of Human Melanoma

1993 ◽  
Vol 8 (3) ◽  
pp. 151-154 ◽  
Author(s):  
A. Anichini ◽  
R. Mortarini ◽  
G. Parmiani
Keyword(s):  
Cell Surface ◽  
Surface Antigens ◽  
Surface Structures ◽  
Biological Behavior ◽  
Cell Surface Antigens ◽  
Membrane Expression ◽  
Neoplastic Cells ◽  
Antigenic Modulation ◽  
Human Malignant Melanoma ◽  
Cell Surface Structures

A number of different cytokines, including IL-1α. and ß, IL-2, IL-3, IL-4, IL-6, IL-7, IL-8, IFN-α, -ß and γ, TNF-α -ß, and TGF-ß1, can modulate the expression of distinct cell surface antigens of normal and neoplastic cells. Both induction/increase of expression and reduction of expression can be achieved depending on the antigen and on the cytokine. Antigens subjected to the modulating activity of cytokines include distinct families of cell surface structures such as the molecules coded by the major histocompatibility complex (MHC), the superfamily of adhesion receptors that regulate cell-cell and cell-matrix interaction, receptors for cytokines and growth factors and tumor-associated antigens. The modulating activity of cytokines is a consequence of their influence on gene expression, protein synthesis, membrane expression and shedding of antigens from the cell surface. The changes of phenotype due to the action of cytokines can influence the signalling pathways dependent on the expression and function of cell surf ace structures. Therefore, the antigen modulating activity of cytokines can thoroughly affect the biological behavior of normal and neoplastic cells. As described here, most of the modulating effects of cytokines on different cell surface structures and the functional consequences of antigenic modulation can be verified in human malignant melanoma cells.

Interleukin 4 (BSF-1) induces growth in resting murine CD8 T cells triggered via cross-linking of T3 cell surface structures

1988 ◽  
Vol 18 (5) ◽  
pp. 767-772 ◽  
Author(s):  
Thomas Miethke ◽  
Ruth Schmidberger ◽  
Klaus Heeg ◽  
Steven Gillis ◽  
Hermann Wagner
Keyword(s):  
T Cells ◽  
Cell Surface ◽  
Cd8 T Cells ◽  
Surface Structures ◽  
Interleukin 4 ◽  
Cross Linking ◽  
Cell Surface Structures

scholarly journals Phosphoethanolamine cellulose enhances curli-mediated adhesion of uropathogenicEscherichia colito bladder epithelial cells

2018 ◽  
Vol 115 (40) ◽  
pp. 10106-10111 ◽  
Author(s):  
Emily C. Hollenbeck ◽  
Alexandra Antonoplis ◽  
Chew Chai ◽  
Wiriya Thongsomboon ◽  
Gerald G. Fuller ◽  
...  
Keyword(s):  
Cell Surface ◽  
Bacterial Cell ◽  
Cell Monolayer ◽  
Surface Structures ◽  
Bacterial Cell Surface ◽  
Cell Surface Structures ◽  
Bladder Cell ◽  
Type 1 Pili ◽  
Tract Infections

UropathogenicEscherichia coli(UPEC) are the major causative agents of urinary tract infections, employing numerous molecular strategies to contribute to adhesion, colonization, and persistence in the bladder niche. Identifying strategies to prevent adhesion and colonization is a promising approach to inhibit bacterial pathogenesis and to help preserve the efficacy of available antibiotics. This approach requires an improved understanding of the molecular determinants of adhesion to the bladder urothelium. We designed experiments using a custom-built live cell monolayer rheometer (LCMR) to quantitatively measure individual and combined contributions of bacterial cell surface structures [type 1 pili, curli, and phosphoethanolamine (pEtN) cellulose] to bladder cell adhesion. Using the UPEC strain UTI89, isogenic mutants, and controlled conditions for the differential production of cell surface structures, we discovered that curli can promote stronger adhesive interactions with bladder cells than type 1 pili. Moreover, the coproduction of curli and pEtN cellulose enhanced adhesion. The LCMR enables the evaluation of adhesion under high-shear conditions to reveal this role for pEtN cellulose which escaped detection using conventional tissue culture adhesion assays. Together with complementary biochemical experiments, the results support a model wherein cellulose serves a mortar-like function to promote curli association with and around the bacterial cell surface, resulting in increased bacterial adhesion strength at the bladder cell surface.

scholarly journals Reticulon 4a promotes exocytosis in mammalian cells

2019 ◽  
Vol 30 (18) ◽  
pp. 2349-2357 ◽  
Author(s):  
Richik Nilay Mukherjee ◽  
Daniel L. Levy
Keyword(s):  
Cell Surface ◽  
Protein Trafficking ◽  
Mammalian Cells ◽  
Cell Types ◽  
Vesicular Trafficking ◽  
Secreted Proteins ◽  
Mammalian Cell Lines ◽  
Rough Er ◽  
Different Cell Types ◽  
Functional Output

Endoplasmic reticulum (ER) tubules and sheets conventionally correspond to smooth and rough ER, respectively. The ratio of ER tubules-to-sheets varies in different cell types and changes in response to cellular conditions, potentially impacting the functional output of the ER. To directly test whether ER morphology impacts vesicular trafficking, we increased the tubule-to-sheet ratio in three different ways, by overexpressing Rtn4a, Rtn4b, or REEP5. Only Rtn4a overexpression increased exocytosis, but not overall levels, of several cell surface and secreted proteins. Furthermore, Rtn4a depletion reduced cell surface trafficking without affecting ER morphology. Similar results were observed in three different mammalian cell lines, suggesting that Rtn4a generally enhances exocytosis independently of changes in ER morphology. Finally, we show that Rtn4a levels modulate cell adhesion, possibly by regulating trafficking of integrins to the cell surface. Taking the results together, we find that altering ER morphology does not necessarily affect protein trafficking, but that Rtn4a specifically enhances exocytosis.

scholarly journals Specialized cell surface structures in cellulolytic bacteria.

1987 ◽  
Vol 169 (8) ◽  
pp. 3792-3800 ◽  
Author(s):  
R Lamed ◽  
J Naimark ◽  
E Morgenstern ◽  
E A Bayer
Keyword(s):  
Cell Surface ◽  
Surface Structures ◽  
Cellulolytic Bacteria ◽  
Specialized Cell ◽  
Cell Surface Structures
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