Search results for "protein binding"
showing 10 items of 870 documents
Enhanced Gene Delivery by Avidin-Displaying Baculovirus
2004
Flexible alteration of virus surface properties would be beneficial for enhanced and targeted gene delivery. A useful approach could be based on a high-affinity receptor–ligand pair, such as avidin and biotin. In this study, we have constructed an avidin-displaying baculovirus, Baavi. Avidin display was expected to enhance cell transduction due to the high positive charge of avidin in physiological pH and to provide a binding site for covering the virus with desired biotinylated ligands. Successful incorporation of avidin on the virus envelope was detected by immunoblotting and electron microscopy. Multiple biotin-binding sites per virus were detected with fluorescence-correlation spectrosc…
Cloning and characterization of Scavidin, a fusion protein for the targeted delivery of biotinylated molecules.
2001
We have constructed a novel fusion protein "Scavidin" consisting of the macrophage scavenger receptor class A and avidin. The Scavidin fusion protein is transported to plasma membranes where the avidin portion of the fusion protein binds biotin with high affinity and forms the basis for the targeted delivery of biotinylated molecules. Subcellular fractionation analysis, immunostaining, and electron microscopy demonstrated endosomal localization of the fusion protein. According to pulse-labeling and cross-linking studies Scavidin is found as monomers (55 kDa), dimers, and multimers, of which the 220-kDa form was the most abundant. The biotin binding capacity and active endocytosis of the bio…
Novel α2β1 integrin inhibitors reveal that integrin binding to collagen under shear stress conditions does not require receptor preactivation.
2012
The interaction between α2β1 integrin (GPIa/IIa, VLA-2) and vascular collagen is one of the initiating events in thrombus formation. Here, we describe two structurally similar sulfonamide derivatives, BTT-3033 and BTT-3034, and show that, under static conditions, they have an almost identical effect on α2-expressing CHO cell adhesion to collagen I, but only BTT-3033 blocks platelet attachment under flow (90 dynes/cm(2)). Differential scanning fluorimetry showed that both molecules bind to the α2I domain of the recombinant α2 subunit. To further study integrin binding mechanism(s) of the two sulfonamides, we created an α2 Y285F mutant containing a substitution near the metal ion-dependent ad…
TREM-1 ligand expression on platelets enhances neutrophil activation
2007
Abstract The triggering receptor expressed on myeloid cells 1 (TREM-1) plays an important role in the innate immune response related to severe infections and sepsis. Modulation of TREM-1–associated activation improves the outcome in rodent models for pneumonia and sepsis. However, the identity and occurrence of the natural TREM-1 ligands are so far unknown, impairing the further understanding of the biology of this receptor. Here, we report the presence of a ligand for TREM-1 on human platelets. Using a recombinant TREM-1 fusion protein, we demonstrate specific binding of TREM-1 to platelets. TREM-1–specific signals are required for the platelet-induced augmentation of polymorphonuclear leu…
Reaggregation and binding of cell wall proteins from Candida albicans to structural polysaccharides
1998
Urea or hot sodium dodecyl sulphate extracted a significant amount of the same proteins from the matrix of the cell wall of the yeast form and mycelial cells of Candida albicans. Gel filtration analysis of the urea-extracted proteins revealed that they occurred in the form of large complexes which were unaffected by up to 8 M urea. Among them, proteins en route to becoming covalently associated within the wall scaffold were identified by their reaction with specific antibodies. When urea was removed by dialysis, some of these proteins specifically reassociated into large aggregates which bound strongly with ConA, whereas others remained soluble in smaller associated products. The ability of…
Selective inhibition of binding of Bacillus thuringiensis Cry1Ab toxin to cadherin-like and aminopeptidase proteins in brush-border membranes and dis…
2007
Binding analyses with denatured epithelial membrane proteins from Bt (Bacillus thuringiensis) demonstrated at least two kinds of proteins, APNs (aminopeptidases N) and cadherin-like proteins, as possible receptors for the Cry1A class of Bt toxins. Two alternative models have been proposed, both based on initial toxin binding to a cadherin-like protein, but one involving APN and the other not. We have used two Bombyx mori strains (J65 and Kin), which are highly susceptible to Cry1Ab, to study the role of these two types of receptors on Cry1Ab toxin binding and cytotoxicity by means of the inhibitory effect of antibodies. BBMVs (brush-border membrane vesicles) of strain J65 incubated with lab…
Binding of Bacillus thuringiensis toxins in resistant and susceptible strains of pink bollworm (Pectinophora gossypiella)
2003
Abstract Evolution of resistance by pests could cut short the success of transgenic plants producing toxins from Bacillus thuringiensis, such as Bt cotton. The most common mechanism of insect resistance to B. thuringiensis is reduced binding of toxins to target sites in the brush border membrane of the larval midgut. We compared toxin binding in resistant and susceptible strains of Pectinophora gossypiella, a major pest of cotton worldwide. Using Cry1Ab and Cry1Ac labeled with 125I and brush border membrane vesicles (BBMV), competition experiments were performed with unlabeled Cry1Aa, Cry1Ab, Cry1Ac, Cry1Ba, Cry1Ca, Cry1Ja, Cry2Aa, and Cry9Ca. In the susceptible strain, Cry1Aa, Cry1Ab, Cry1…
Association of Cry1Ac toxin resistance in Helicoverpa zea (Boddie) with increased alkaline phosphatase levels in the midgut lumen.
2012
ABSTRACT Resistance to Bacillus thuringiensis Cry1Ac toxin was characterized in a population of Helicoverpa zea larvae previously shown not to have an alteration in toxin binding as the primary resistance mechanism to this toxin. Cry1Ac-selected larvae (AR1) were resistant to protoxins and toxins of Cry1Ab, Cry1Ac, and the corresponding modified proteins lacking helix α-1 (Cry1AbMod and Cry1AcMod). When comparing brush border membrane vesicles (BBMVs) prepared from susceptible (LC) and AR1 larval midguts, there were only negligible differences in overall Cry1Ac toxin binding, though AR1 had 18% reversible binding, in contrast to LC, in which all binding was irreversible. However, no differe…
CTCF and BORIS Regulate Rb2/p130 Gene Transcription: A Novel Mechanism and a New Paradigm for Understanding the Biology of Lung Cancer
2011
Abstract Although innumerable investigations regarding the biology of lung cancer have been carried out, many aspects thereof remain to be addressed, including the role played by the retinoblastoma-related protein Rb2/p130 during the evolution of this disease. Here we report novel findings on the mechanisms that control Rb2/p130 gene expression in lung fibroblasts and characterize the effects of Rb2/p130 deregulation on the proliferative features of lung cancer cells. We revealed for the first time that in lung fibroblasts the expression of Rb2/p130 gene is directly controlled by the chromatin insulator CCCTC-binding factor, CTCF, which by binding to the Rb2/p130 gene promoter induces, and/…
Induction of CD36 and thrombospondin-1 in macrophages by hypoxia-inducible factor 1 and its relevance in the inflammatory process.
2012
Inflammation is part of a complex biological response of vascular tissue to pathogens or damaged cells. First inflammatory cells attempt to remove the injurious stimuli and this is followed by a healing process mediated principally by phagocytosis of senescent cells. Hypoxia and p38-MAPK are associated with inflammation, and hypoxia inducible factor 1 (HIF-1) has been detected in inflamed tissues. We aimed to analyse the role of p38-MAPK and HIF-1 in the transcriptional regulation of CD36, a class B scavenger receptor, and its ligand thrombospondin (TSP-1) in macrophages and to evaluate the involvement of this pathway in phagocytosis of apoptotic neutrophils. We have also assessed HIF-1α, p…