Search results for "PEPTIDE"
showing 10 items of 4589 documents
Viral Bcl2s' transmembrane domain interact with host Bcl2 proteins to control cellular apoptosis
2020
© The Author(s) 2020.
Elastin-derived peptide VGVAPG affects the proliferation of mouse cortical astrocytes with the involvement of aryl hydrocarbon receptor (Ahr), peroxi…
2019
Abstract During aging and ischemic and hemorrhagic stroke, elastin molecules are degraded and elastin-derived peptides are released into the brain microenvironment. Val-Gly-Val-Ala-Pro-Gly (VGVAPG) is a repeating hexapeptide in the elastin molecule. It is well documented that the peptide sequence binds with high affinity to elastin-binding protein (EBP) located on the cell surface, thereby transducing a molecular signal into the cell. The aim of our study was to investigate whether EBP, aryl hydrocarbon receptor (Ahr), and peroxisome proliferator-activated receptor gamma (Pparγ) are involved in VGVAPG-stimulated proliferation. Primary astrocytes were maintained in DMEM/F12 medium without ph…
Artefactual band patterns by SDS-PAGE of the Vip3Af protein in the presence of proteases mask the extremely high stability of this protein.
2018
Abstract Vip3 proteins are secretable proteins from Bacillus thuringiensis with important characteristics for the microbiological control of agricultural pests. The exact details of their mode of action are yet to be disclosed and the crystallographic structure is still unknown. Vip3 proteins are expressed as protoxins that have to be activated by the insect gut proteases. A previous study on the peptidase processing of Vip3Aa revealed that the protoxin produced artefactual band patterns by SDS-PAGE due to the differential stability of this protein and the peptidases to SDS and heating (Bel et al., 2017 Toxins 9:131). To determine whether this phenomenon also applies to other Vip3A proteins…
Protease‐activated receptor signaling in intestinal permeability regulation
2019
Protease-activated receptors (PARs) are a unique class of G-protein-coupled transmembrane receptors, which revolutionized the perception of proteases from degradative enzymes to context-specific signaling factors. Although PARs are traditionally known to affect several vascular responses, recent investigations have started to pinpoint the functional role of PAR signaling in the gastrointestinal (GI) tract. This organ is exposed to the highest number of proteases, either from the gut lumen or from the mucosa. Luminal proteases include the host's digestive enzymes and the proteases released by the commensal microbiota, while mucosal proteases entail extravascular clotting factors and the enzy…
Insights into the Structure of the Vip3Aa Insecticidal Protein by Protease Digestion Analysis
2017
Vip3 proteins are secretable proteins from Bacillus thuringiensis whose mode of action is still poorly understood. In this study, the activation process for Vip3 proteins was closely examined in order to better understand the Vip3Aa protein stability and to shed light on its structure. The Vip3Aa protoxin (of 89 kDa) was treated with trypsin at concentrations from 1:100 to 120:100 (trypsin:Vip3A, w:w). If the action of trypsin was not properly neutralized, the results of SDS-PAGE analysis (as well as those with Agrotis ipsilon midgut juice) equivocally indicated that the protoxin could be completely processed. However, when the proteolytic reaction was efficiently stopped, it was revealed t…
Host Cell Calpains Can Cleave Structural Proteins from the Enterovirus Polyprotein
2019
Enteroviruses are small RNA viruses that cause diseases with various symptoms ranging from mild to severe. Enterovirus proteins are translated as a single polyprotein, which is cleaved by viral proteases to release capsid and nonstructural proteins. Here, we show that also cellular calpains have a potential role in the processing of the enteroviral polyprotein. Using purified calpains 1 and 2 in an in vitro assay, we show that addition of calpains leads to an increase in the release of VP1 and VP3 capsid proteins from P1 of enterovirus B species, detected by western blotting. This was prevented with a calpain inhibitor and was dependent on optimal calcium concentration, especially for calpa…
Aβ Induces Excitotoxicity Mediated by APC/C-Cdh1 Depletion That Can Be Prevented by Glutaminase Inhibition Promoting Neuronal Survival
2016
AbstractThe E3 ubiquitin ligase anaphase-promoting complex/cyclosome (APC/C) is activated by the fizzy-related protein homolog/CDC20-like protein 1 (cdh1) in post-mitotic neurons. Growing evidence suggests that dysregulation of APC/C-Cdh1 is involved in neurodegenerative diseases. Here we show in neurons that oligomers of amyloid beta (Aβ), a peptide related to Alzheimer’s disease, cause proteasome-dependent degradation of cdh1. This leads to a subsequent increase in glutaminase (a degradation target of APC/C-Cdh1), which causes an elevation of glutamate levels and further intraneuronal Ca2+ dysregulation, resulting in neuronal apoptosis. Glutaminase inhibition prevents glutamate excitotoxi…
Lunasin is a redox sensitive intrinsically disordered peptide with two transiently populated α-helical regions.
2016
Lunasin is a 43 amino acid peptide with anti-cancer, antioxidant, anti-inflammatory and cholesterol-lowering properties. Although the mechanism of action of lunasin has been characterized to some extent, its exact three-dimensional structure as well as the function of the N-terminal sequence remains unknown. We established a novel method for the production of recombinant lunasin that allows efficient isotope labeling for NMR studies. Initial studies showed that lunasin can exist in a reduced or oxidized state with an intramolecular disulfide bond depending on solution conditions. The structure of both forms of the peptide at pH 3.5 and 6.5 was characterized by CD spectroscopy and multidimen…
Ephestia kuehniella tolerance to Bacillus thuringiensis Cry1Aa is associated with reduced oligomer formation
2016
The basis of the different susceptibility of Ephestia kuehniella to the Cry1Aa and Cry1Ac δ-endotoxins from Bacillus thuringiensis kurstaki BNS3 was studied. Both toxins bound specifically to the BBMV of E. kuehniella. The result of the ligand blot showed that Cry1Ac bound to three putative receptors of about 100, 65 and 80 kDa and Cry1Aa interacted only with a 100 kDa protein. Pronase digestion of the BBMV-bound toxins was used to analyze the toxin insertion. Both toxins inserted into the BBMV as monomers however, a 14 kDa peptide of α4-α5 which correspond to the oligomeric form of this peptide was detected in case of Cry1Ac only. Analysis of the in vitro oligomerisation of these toxins in…
Plasmin-Induced Activation of Human Platelets Is Modulated by Thrombospondin-1, Bona Fide Misfolded Proteins and Thiol Isomerases
2020
Inflammatory processes are triggered by the fibrinolytic enzyme plasmin. Tissue-type plasminogen activator, which cleaves plasminogen to plasmin, can be activated by the cross-&beta