scholarly journals TETRALEC, Artificial Tetrameric Lectins: A Tool to Screen Ligand and Pathogen Interactions

2020 ◽  
Vol 21 (15) ◽  
pp. 5290 ◽  
Author(s):  
Silvia Achilli ◽  
João T. Monteiro ◽  
Sonia Serna ◽  
Sabine Mayer-Lambertz ◽  
Michel Thépaut ◽  
...  
Keyword(s):  
Binding Capacity ◽  
Spatial Arrangement ◽  
Carbohydrate Recognition Domain ◽  
Carbohydrate Recognition ◽  
Binding Profile ◽  
Affinity Ligands ◽  
Lectin Receptor ◽  
Naturally Occurring ◽  
Multivalent Display

C-type lectin receptor (CLR)/carbohydrate recognition occurs through low affinity interactions. Nature compensates that weakness by multivalent display of the lectin carbohydrate recognition domain (CRD) at the cell surface. Mimicking these low affinity interactions in vitro is essential to better understand CLR/glycan interactions. Here, we present a strategy to create a generic construct with a tetrameric presentation of the CRD for any CLR, termed TETRALEC. We applied our strategy to a naturally occurring tetrameric CRD, DC-SIGNR, and compared the TETRALEC ligand binding capacity by synthetic N- and O-glycans microarray using three different DC-SIGNR constructs i) its natural tetrameric counterpart, ii) the monomeric CRD and iii) a dimeric Fc-CRD fusion. DC-SIGNR TETRALEC construct showed a similar binding profile to that of its natural tetrameric counterpart. However, differences observed in recognition of low affinity ligands underlined the importance of the CRD spatial arrangement. Moreover, we further extended the applications of DC-SIGNR TETRALEC to evaluate CLR/pathogens interactions. This construct was able to recognize heat-killed Candida albicans by flow cytometry and confocal microscopy, a so far unreported specificity of DC-SIGNR. In summary, the newly developed DC-SIGNR TETRALEC tool proved to be useful to unravel novel CLR/glycan interactions, an approach which could be applied to other CLRs.

scholarly journals Toxicity and Binding Profile of Lectins from the GenusCanavaliaon Brine Shrimp

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Francisco Vassiliepe Sousa Arruda ◽  
Arthur Alves Melo ◽  
Mayron Alves Vasconcelos ◽  
Romulo Farias Carneiro ◽  
Ito Liberato Barroso-Neto ◽  
...  
Keyword(s):  
Structural Analysis ◽  
Brine Shrimp ◽  
Cytotoxic Effect ◽  
Spatial Arrangement ◽  
Carbohydrate Recognition Domain ◽  
Biological Functions ◽  
Biotechnological Potential ◽  
Binding Profile ◽  
Similar Area ◽  
The Relationship

Lectins are sugar-binding proteins widely distributed in nature with many biological functions. Although many lectins have a remarkable biotechnological potential, some of them can be cytotoxic. Thus, the aim of this study was to assess the toxicity of five lectins, purified from seeds of different species ofCanavaliagenus. In order to determine the toxicity, assays withArtemianauplii were performed. In addition, a fluorescence assay was carried out to evaluate the binding of lectins toArtemianauplii. In order to verify the relationship between the structure of lectins and their cytotoxic effect, structural analysis was carried out to evaluate the volume of the carbohydrate recognition domain (CRD) of each lectin. The results showed that all lectins exhibited different toxicities and bound to a similar area in the digestive tract ofArtemianauplii. Concerning the structural analysis, differences in spatial arrangement and volume of CRD may explain the variation of the toxicity exhibited by each lectin. To this date, this is the first study that establishes a link between toxicity and structure of CRD from Diocleinae lectins.

scholarly journals Interaction of egg-white glycoproteins and their oligosaccharides with the monomer and the hexamer of chicken liver lectin. A multivalent oligosaccharide-combining site exists within the carbohydrate-recognition domain

1990 ◽  
Vol 270 (3) ◽  
pp. 755-760 ◽  
Author(s):  
V E Piskarev ◽  
J Navrátil ◽  
H Karásková ◽  
K Bezouska ◽  
J Kocourek
Keyword(s):  
Equilibrium Dialysis ◽  
Spatial Arrangement ◽  
Egg White ◽  
Carbohydrate Recognition Domain ◽  
Carbohydrate Recognition ◽  
Direct Binding ◽  
Solubilized Form ◽  
Inhibition Studies ◽  
Hexameric Form ◽  
Binding Glycoprotein

Binding of egg-white glycoproteins and their oligosaccharides to hexameric solubilized form of the chicken hepatic lectin and the monomeric soluble fragment containing the carbohydrate-recognition domain has been investigated by several techniques. Ligand blotting revealed significant differences in binding to two forms of the lectin only for glycoproteins bearing multiple N-linked oligosaccharide moieties in their molecule (riboflavin-binding glycoprotein, avidin or ovomucoid). Inhibition studies indicated that inhibitory potency in a series of linear and branched N-acetyl-D-glucosamine-terminated oligosaccharides is critically dependent on the number and spatial arrangement of the terminal monosaccharide residues for both forms of the lectin. Direct binding of 4-hydroxyphenyl-derivatized radioiodinated oligosaccharides measured by equilibrium dialysis and frontal affinity chromatography points to the existence of two N-acetyl-D-glucosamine-combining sites per one subunit of the lectin, as has been recently reported for the rabbit and rat liver lectin [Lee & Lee (1988) Biochem. Biophys. Res. Commun. 155, 1444-1452]. Highly branch (penta-antennary) oligosaccharides interact with more than one subunit of the hexameric form of the lectin and thus resemble the more complex interaction of the whole glycoprotein.

Endo180, an endocytic recycling glycoprotein related to the macrophage mannose receptor is expressed on fibroblasts, endothelial cells and macrophages and functions as a lectin receptor

2000 ◽  
Vol 113 (6) ◽  
pp. 1021-1032 ◽  
Author(s):  
H. Sheikh ◽  
H. Yarwood ◽  
A. Ashworth ◽  
C.M. Isacke
Keyword(s):  
Endothelial Cells ◽  
Mannose Receptor ◽  
Carbohydrate Recognition ◽  
Lectin Receptor ◽  
Extracellular Milieu ◽  
Morphological Studies ◽  
Macrophage Mannose Receptor ◽  
Polypeptide Backbone

Endo180 was previously characterized as a novel, cell type specific, recycling transmembrane glycoprotein. This manuscript describes the isolation of a full length human Endo180 cDNA clone which was shown to encode a fourth member of a family of proteins comprising the macrophage mannose receptor, the phospholipase A(2) receptor and the DEC-205/MR6 receptor. This receptor family is unusual in that they contain 8–10 C-type lectin carbohydrate recognition domains in a single polypeptide backbone, however, only the macrophage mannose receptor had been shown to function as a lectin. Sequence analysis of Endo180 reveals that the second carbohydrate recognition domain has retained key conserved amino acids found in other functional C-type lectins. Furthermore, it is demonstrated that this protein displays Ca(2+)-dependent binding to N-acetylglucosamine but not mannose affinity columns. In order to characterize the physiological function of Endo180, a series of biochemical and morphological studies were undertaken. Endo180 is found to be predominantly expressed in vivo and in vitro on fibroblasts, endothelial cells and macrophages, and the distribution and post-translational processing in these cells is consistent with Endo180 functioning to internalize glycosylated ligands from the extracellular milieu for release in an endosomal compartment.

scholarly journals Pivotal role of the carbohydrate recognition domain in self-interaction of CLEC4A to elicit the ITIM-mediated inhibitory function in murine conventional dendritic cells in vitro

2020 ◽  
Vol 32 (10) ◽  
pp. 673-682 ◽  
Author(s):  
Junta Nasu ◽  
Tomofumi Uto ◽  
Tomohiro Fukaya ◽  
Hideaki Takagi ◽  
Takehito Fukui ◽  
...  
Keyword(s):  
Dendritic Cells ◽  
Cell Line ◽  
Glycosylation Site ◽  
The Self ◽  
Pivotal Role ◽  
Carbohydrate Recognition Domain ◽  
Carbohydrate Recognition ◽  
Lectin Receptors

Abstract C-type lectin receptors (CLRs), pattern recognition receptors (PRRs) with a characteristic carbohydrate recognition domain (CRD) in the extracellular portion, mediate crucial cellular functions upon recognition of glycosylated pathogens and self-glycoproteins. CLEC4A is the only classical CLR that possesses an intracellular immunoreceptor tyrosine-based inhibitory motif (ITIM), which possibly transduces negative signals. However, how CLEC4A exerts cellular inhibition remains unclear. Here, we report that the self-interaction of CLEC4A through the CRD is required for the ITIM-mediated suppressive function in conventional dendritic cells (cDCs). Human type 2 cDCs (cDC2) and monocytes display a higher expression of CLEC4A than cDC1 and plasmacytoid DCs (pDCs) as well as B cells. The extracellular portion of CLEC4A specifically binds to a murine cDC cell line expressing CLEC4A, while its extracellular portion lacking the N-glycosylation site or the EPS motif within the CRD reduces their association. Furthermore, the deletion of the EPS motif within the CRD or ITIM in CLEC4A almost completely impairs its suppressive effect on the activation of the murine cDC cell line, whereas the absence of the N-glycosylation site within the CRD exhibits partial inhibition on their activation. On the other hand, antagonistic monoclonal antibody (mAb) to CLEC4A, which inhibits the self-interaction of CLEC4A and its downstream signaling in murine transfectants, enhances the activation of monocytes and monocyte-derived immature DCs upon stimulation with a Toll-like receptor (TLR) ligand. Thus, our findings suggest a pivotal role of the CRD in self-interaction of CLEC4A to elicit the ITIM-mediated inhibitory signal for the control of the function of cDCs.

scholarly journals IMMUNOLOGICAL REACTIONS WITH A VIRUS CAUSING PAPILLOMAS IN RABBITS

1938 ◽  
Vol 68 (5) ◽  
pp. 737-759 ◽  
Author(s):  
John G. Kidd
Keyword(s):  
Binding Capacity ◽  
High Titer ◽  
Immune Serum ◽  
Naturally Occurring ◽  
Antibody Titers ◽  
Immunological Reactions ◽  
Domestic Rabbits ◽  
Do So

A study has been made of the yield of virus and of the complement-binding antigen from the virus-induced papillomas of cottontail and domestic rabbits. Extracts of the discrete, naturally occurring papillomas of cottontail rabbits usually contain virus in large amount; and, as a rule, they also contain the complement-binding antigen in high titer. The confluent growths produced experimentally with the virus in some cottontails, on the other hand, often fail to yield the virus, or furnish it in small amount; and extracts of them have little if any complement-binding capacity. The sera of cottontails with massive papillomas from which the virus cannot be recovered often have high antibody titers. Many extracts were tested of the virus-induced papillomas of domestic rabbits. None contained the virus in large amount, and the majority of them failed to manifest it on sensitive test. A few fixed complement in low titer when mixed with immune sera, but most failed to do so. Crude extracts of the "non-infectious," virus-induced papillomas of domestic rabbits stimulated the formation of virus-neutralizing and complement-binding antibodies in low titer when injected intraperitoneally into normal rabbits of the same breed, but Berkefeld filtrates of the same materials proved devoid of this immunizing effect. The significance of the findings described in the three papers is discussed. The evidence as a whole favors the view that the virus stimulates the formation of the virus-neutralizing and complement-binding antibodies in vivo, and many facts indicate that it is closely associated, and in all probability identical, with the antigen that reacts with immune serum to fix complement in vitro.

scholarly journals Insoluble glycogen, a metabolizable internal adsorbent, decreases the lethality of endotoxin shock in rats

1997 ◽  
Vol 6 (5-6) ◽  
pp. 319-322
Author(s):  
S. Sipka ◽  
G. Bot ◽  
P. Gergely ◽  
L. Bertók ◽  
J. Csongor ◽  
...  
Keyword(s):  
Binding Capacity ◽  
Interleukin 1 ◽  
Endotoxin Shock ◽  
Tumour Necrosis Factor Alpha ◽  
Male Rats ◽  
Necrosis Factor Alpha ◽  
Naturally Occurring ◽  
Factor Alpha ◽  
Necrosis Factor

Insoluble glycogen is an enzymatically modified form of naturally occurring soluble glycogen with a great adsorbing capacity. It can be metabolized by phagocytes to glucose. In this study we used insoluble glycogen intravenously in the experimental endotoxin shock of rats. Wistar male rats were sensitized to endotoxin by Pb acetate. The survival of rats were compared in groups of animals endotoxin shock treated and non-treated with insoluble glycogen. Furthermore, we have determinedin vitrothe binding capacity of insoluble glycogen for endotoxin, tumour necrosis factor alpha, interleukin-1 and secretable phospholipase A2. Use of 10 mg/kg dose of insoluble glycogen could completely prevent the lethality of shock induced by LD50quantity of endotoxin in rats. All animals treated survived. Insoluble glycogen is a form of ‘metabolizable internal adsorbents’. It can potentially be used for treatment of septic shock.

scholarly journals Impairment of the Hypothalamus–Pituitary–Thyroid Axis Caused by Naturally Occurring GATA2 Mutations In Vitro

2021 ◽  
Vol 22 (18) ◽  
pp. 10015
Author(s):  
Yuki Sakai ◽  
Kenji Ohba ◽  
Shigekazu Sasaki ◽  
Akio Matsushita ◽  
Hiroko Misawa Nakamura ◽  
...  
Keyword(s):  
Dna Binding ◽  
Transcriptional Activity ◽  
Binding Capacity ◽  
Loss Of Function ◽  
Hematological Disorders ◽  
Naturally Occurring ◽  
Pituitary Thyroid Axis ◽  
Thyroid Axis ◽  
Hpt Axis

The transcription factor GATA2 regulates gene expression in several cells and tissues, including hematopoietic tissues and the central nervous system. Recent studies revealed that loss-of-function mutations in GATA2 are associated with hematological disorders. Our earlier in vitro studies showed that GATA2 plays an essential role in the hypothalamus–pituitary–thyroid axis (HPT axis) by regulating the genes encoding prepro-thyrotropin-releasing hormone (preproTRH) and thyroid-stimulating hormone β (TSHβ). However, the effect of GATA2 mutants on the transcriptional activity of their promoters remains unelucidated. In this study, we created five human GATA2 mutations (R308P, T354M, R396Q, R398W, and S447R) that were reported to be associated with hematological disorders and analyzed their functional properties, including transactivation potential and DNA-binding capacity toward the preproTRH and the TSHβ promoters. Three mutations (T354M, R396Q, and R398W) within the C-terminal zinc-finger domain reduced the basal GATA2 transcriptional activity on both the preproTRH and the TSHβ promoters with a significant loss of DNA binding affinity. Interestingly, only the R398W mutation reduced the GATA2 protein expression. Subsequent analysis demonstrated that the R398W mutation possibly facilitated the GATA2 degradation process. R308P and S447R mutants exhibited decreased transcriptional activity under protein kinase C compared to the wild-type protein. In conclusion, we demonstrated that naturally occurring GATA2 mutations impair the HPT axis through differential functional mechanisms in vitro.

Placental protein 13: Characterization of a naturally occurring variant lacking the carbohydrate recognition domain

Placenta ◽  
2014 ◽  
Vol 35 (9) ◽  
pp. A84
Author(s):  
Marei Sammar ◽  
Berthold Huppertz ◽  
Sveinbjorn Gizurarson ◽  
Hamutal Meiri ◽  
George Osol
Keyword(s):  
Carbohydrate Recognition Domain ◽  
Carbohydrate Recognition ◽  
Naturally Occurring ◽  
Placental Protein

Investigation of the Free and Total Thyroxine-binding Capacity of Plasma Proteins in Thyroid Disorders

1971 ◽  
Vol 10 (04) ◽  
pp. 299-304
Author(s):  
József Takó ◽  
János Fischer ◽  
Jusztina Juhász ◽  
Ilona Sztraka ◽  
István Kapus ◽  
...  
Keyword(s):  
Blood Cell ◽  
Thyroid Function ◽  
Oral Contraceptives ◽  
Red Blood Cell ◽  
Plasma Proteins ◽  
Binding Capacity ◽  
Thyroid Disorders ◽  
Thyroid Function Tests ◽  
Total Thyroxine

SummaryThe results of thyroid function tests have been compared with data on the thyroxine-binding capacity of plasma proteins in hyper-, hypo- and euthyroid cases, the latter including women taking oral contraceptives (Infecundin). It was found that there exists a significant correlation of exponential nature between the in vitro red blood cell 125I-triiodothyronine uptake (RCU) and the free thyroxine-binding capacity of the thyroxine-inding globulin (TBG).

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