scholarly journals Mechanism of human lymphocyte stimulation by concanavalin A: role of valence and surface binding sites.

1976 ◽  
Vol 73 (6) ◽  
pp. 2118-2122 ◽  
Author(s):  
J. R. Wands ◽  
D. K. Podolsky ◽  
K. J. Isselbacher
Keyword(s):  
Concanavalin A ◽  
Human Lymphocyte ◽  
Binding Sites ◽  
Lymphocyte Stimulation ◽  
Surface Binding

scholarly journals Glycophorin A interferes in the agglutination of human erythrocytes by concanavalin A Explanation of the requirement for enzymic predigestion

1987 ◽  
Vol 241 (2) ◽  
pp. 505-511 ◽  
Author(s):  
S M Gokhale ◽  
N G Mehta
Keyword(s):  
Sialic Acid ◽  
Correlation Coefficient ◽  
Concanavalin A ◽  
Binding Sites ◽  
Band 3 ◽  
Human Erythrocytes ◽  
The Other ◽  
Glycophorin A ◽  
Con A

Human erythrocytes become agglutinable with concanavalin A (Con A) after treatment with various proteinases or neuraminidase. The extent of agglutinability achieved with different enzymes is, however, different: Pronase, papain, trypsin, neuraminidase and chymotrypsin enhance the agglutinability in decreasing order, the last being barely effective. The actions of the enzymes on band 3, the Con A receptor, do not correlate with their abilities to increase the agglutinability: Pronase, papain and chymotrypsin cleave the protein, but not trypsin or neuraminidase. No significant differences are found in the number of Con A-binding sites or the affinities for the lectin between the normal and trypsin- or Pronase-treated cells. Thus the receptor does not seem to play a role in determining the Con A-agglutinability of erythrocytes. On the other hand, the cleavage of glycophorins, especially glycophorin A, and the release of sialic acid (in the peptide-bound form) are well-correlated with the enhancement in agglutination after the action of proteinases. The release of sialic acid by graded neuraminidase digestion and the increase in Con A-agglutinability show a correlation coefficient of 0.88. The major inhibitory role of glycophorin A in the process is indicated by the agglutination of En(a) heterozygous erythrocytes; the cells, known to bear about 50% glycophorin A molecules in their membrane, are agglutinated approximately half as well without proteolysis as are the trypsin-treated cells. Possible mechanisms by which glycophorin A could affect Con A-mediated agglutination are discussed.

scholarly journals Peroxidase and gold complexes of lectins for double labeling of surface-binding sites by electron microscopy.

1977 ◽  
Vol 25 (10) ◽  
pp. 1181-1184 ◽  
Author(s):  
J Roth ◽  
M Wagner
Keyword(s):  
Electron Microscopy ◽  
Horseradish Peroxidase ◽  
Concanavalin A ◽  
Binding Sites ◽  
Lectin Binding ◽  
Helix Pomatia ◽  
Surface Binding ◽  
Double Labeling ◽  
Membrane Bound ◽  
Lectin Binding Sites

Double labeling experiments were performed for visualization of the binding sites of Concanavalin A and anti-AHel (the lectin from Helix pomatia). The anti-AHel was labeled with the colloidal gold whereas the membrane bound Concanavalin A was demonstrated by an affinity technique using horseradish peroxidase. The two markers used could be clearly distinguished electron microscopically. The specificity of the cell surface double labeling was demonstrated in the control experiments. A topological distinct localization of the both lectin-binding sites is evident.

The role of microbiota in concanavalin A-mediated liver injury

2018 ◽  
Vol 56 (01) ◽  
pp. E2-E89
Author(s):  
B Schiller ◽  
C Wegscheid ◽  
L Berkhout ◽  
A Zarzycka ◽  
U Steinhoff ◽  
...  
Keyword(s):  
Liver Injury ◽  
Concanavalin A

scholarly journals The MarR-Type Regulator PA3458 Is Involved in Osmoadaptation Control in Pseudomonas aeruginosa

2021 ◽  
Vol 22 (8) ◽  
pp. 3982
Author(s):  
Karolina Kotecka ◽  
Adam Kawalek ◽  
Kamil Kobylecki ◽  
Aneta Agnieszka Bartosik
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Binding Sites ◽  
Transcriptional Profiling ◽  
Mrna Level ◽  
Transcriptional Regulators ◽  
Resistance Mechanisms ◽  
Chronic Infections ◽  
Environmental Signals ◽  
Regulatory Systems

Pseudomonas aeruginosa is a facultative human pathogen, causing acute and chronic infections that are especially dangerous for immunocompromised patients. The eradication of P. aeruginosa is difficult due to its intrinsic antibiotic resistance mechanisms, high adaptability, and genetic plasticity. The bacterium possesses multilevel regulatory systems engaging a huge repertoire of transcriptional regulators (TRs). Among these, the MarR family encompasses a number of proteins, mainly acting as repressors, which are involved in response to various environmental signals. In this work, we aimed to decipher the role of PA3458, a putative MarR-type TR from P. aeruginosa. Transcriptional profiling of P. aeruginosa PAO1161 overexpressing PA3458 showed changes in the mRNA level of 133 genes; among them, 100 were down-regulated, suggesting the repressor function of PA3458. Concomitantly, ChIP-seq analysis identified more than 300 PA3458 binding sites in P. aeruginosa. The PA3458 regulon encompasses genes involved in stress response, including the PA3459–PA3461 operon, which is divergent to PA3458. This operon encodes an asparagine synthase, a GNAT-family acetyltransferase, and a glutamyl aminopeptidase engaged in the production of N-acetylglutaminylglutamine amide (NAGGN), which is a potent bacterial osmoprotectant. We showed that PA3458-mediated control of PA3459–PA3461 expression is required for the adaptation of P. aeruginosa growth in high osmolarity. Overall, our data indicate that PA3458 plays a role in osmoadaptation control in P. aeruginosa.

scholarly journals The Role of Putative Fibrinogen Aα-, Bβ-, and γA-chain Integrin Binding Sites in Endothelial Cell-mediated Clot Retraction

1997 ◽  
Vol 272 (35) ◽  
pp. 22080-22085 ◽  
Author(s):  
Richard A. Smith ◽  
M. W. Mosesson ◽  
Michael M. Rooney ◽  
Susan T. Lord ◽  
A.U. Daniels ◽  
...  
Keyword(s):  
Endothelial Cell ◽  
Binding Sites ◽  
Clot Retraction

scholarly journals TP53-Induced Glycolysis and Apoptosis Regulator (TIGAR) Is Upregulated in Lymphocytes Stimulated with Concanavalin A

2021 ◽  
Vol 22 (14) ◽  
pp. 7436
Author(s):  
Helga Simon-Molas ◽  
Xavier Vallvé-Martínez ◽  
Irene Caldera-Quevedo ◽  
Pere Fontova ◽  
Claudia Arnedo-Pac ◽  
...  
Keyword(s):  
Concanavalin A ◽  
Carbon Flux ◽  
Human Lymphocytes ◽  
Tumor Development ◽  
Pentose Phosphate ◽  
Akt Signaling Pathway ◽  
G6pdh Activity ◽  
Physiological Conditions ◽  
Glucose 6 Phosphate Dehydrogenase

The glycolytic modulator TP53-Inducible Glycolysis and Apoptosis Regulator (TIGAR) is overexpressed in several types of cancer and has a role in metabolic rewiring during tumor development. However, little is known about the role of this enzyme in proliferative tissues under physiological conditions. In the current work, we analysed the role of TIGAR in primary human lymphocytes stimulated with the mitotic agent Concanavalin A (ConA). We found that TIGAR expression was induced in stimulated lymphocytes through the PI3K/AKT pathway, since Akti-1/2 and LY294002 inhibitors prevented the upregulation of TIGAR in response to ConA. In addition, suppression of TIGAR expression by siRNA decreased the levels of the proliferative marker PCNA and increased cellular ROS levels. In this model, TIGAR was found to support the activity of glucose 6-phosphate dehydrogenase (G6PDH), the first enzyme of the pentose phosphate pathway (PPP), since the inhibition of TIGAR reduced G6PDH activity and increased autophagy. In conclusion, we demonstrate here that TIGAR is upregulated in stimulated human lymphocytes through the PI3K/AKT signaling pathway, which contributes to the redirection of the carbon flux to the PPP.

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