Search results for "Internalization"
showing 10 items of 159 documents
Trafficking of the human transferrin receptor in plant cells: effects of tyrphostin A23 and brefeldin A.
2006
Plant cells possess much of the molecular machinery necessary for receptor-mediated endocytosis (RME), but this process still awaits detailed characterization. In order to identify a reliable and well-characterized marker to investigate RME in plant cells, we have expressed the human transferrin receptor (hTfR) in Arabidopsis protoplasts. We have found that hTfR is mainly found in endosomal (Ara7- and FM4-64-positive) compartments, but also at the plasma membrane, where it mediates binding and internalization of its natural ligand transferrin (Tfn). Cell surface expression of hTfR increases upon treatment with tyrphostin A23, which inhibits the interaction between the YTRF endocytosis signa…
Characterization of the cleavage site and function of resulting cleavage fragments after limited proteolysis of Clostridium difficile toxin B (TcdB) …
2005
Clostridium difficiletoxin B (TcdB) is a single-stranded protein consisting of a C-terminal domain responsible for binding to the host cell membrane, a middle part involved in internalization, and the N-terminal catalytic (toxic) part. This study shows that TcdB is processed by a single proteolytic step which cleaves TcdB10463between Leu543and Gly544and the naturally occurring variant TcdB8864between Leu544and Gly545. The cleavage occurs at neutral pH and is catalysed by a pepstatin-sensitive protease localized in the cytoplasm and on the cytoplasmic face of intracellular membranes. The smaller N-terminal cleavage products [63 121 Da (TcdB10463) and 62 761 Da (TcdB8864)] harbour the cytotox…
The endocytic trafficking pathway of oncogenic papillomaviruses
2019
Over the last two decades many host cell proteins have been described to be involved in the process of infectious entry of oncogenic human papillomaviruses (HPV). After initial binding and priming of the capsid, a sequence of events on the cell surface precedes the formation of the HPV entry platform. It has been shown that the virus-associated entry complex consists of membrane organizers, tetraspanins CD151 and CD63, and their associated partner proteins such as integrins, growth factor receptors, and the annexin A2 heterotetramer. Further recruitment of cytoplasmic factors such as the obscurin-like protein 1 and actin results in a non-canonical clathrin-independent endocytosis of the vir…
Impact of Ceramic and Metallic Nano-scaled Particles on Endothelial Cell Functionsin vitro
2007
The sections in this article are Introduction Origin of Particles in the Human Environment Evidence for Size-dependent Toxicity of Particles Dissemination and Interferences of Nanoparticles within the Body Endothelial Cells and Nanoparticle Exposure Testing of Nanoparticle-induced Effects on Human Endothelial Cells In Vitro Materials and Methods Cell Culture Particles Transmission Electron Microscopy (TEM) Cytotoxicity Assay Detection of Ki67 Expression Quantification of IL-8 Release in Cell Culture Supernatant Quantification of E-selectin Cell Surface Protein Expression Fluorescence Staining Statistical Analysis Results Discussion Particle Internalization Particle Cytotoxicity Pro-inflamma…
Selective loss of pertussis toxin-sensitive G-proteins from the plasma membrane after antibody-induced internalization of T-cell surface molecules.
1991
Antibody-induced antigenic modulation occurs after binding of antibodies to a variety of cell surface proteins. It is characterized by aggregation and subsequent loss of the molecules from the cell surface, usually by internalization. In this study we have investigated the effect of modulation of the T-cell antigen receptor complex (TCR) and the transferrin receptor (TFR) on the distribution of cholera toxin (CTx)- and pertussis toxin (PTx)-sensitive GTP binding proteins in human T-lymphocytes. Modulation of both the TCR and the TFR induced a selective shift of PTx-sensitive G-proteins from the plasma membrane to a high density membrane fraction enriched for lysosomal membranes. The distrib…
Single-cell RNA sequencing of SARS-CoV-2 cell entry factors in the preconceptional human endometrium.
2021
Abstract STUDY QUESTION Are SARS-CoV-2 canonical cell entry machinery, consisting of ACE2, TMPRSS2, NRP1 and LY6E, or alternative potential cell entry machinery, consisting of BSG, ANPEP, CD209, CLEC4G, TMPRSS4, TMPRSS11A, FURIN, CTSB, CTSL and IFITM1, expressed in the human endometrium across the menstrual cycle? SUMMARY ANSWER Analysis of cell entry factors for SARS-CoV-2 by single-cell RNA-sequencing (scRNAseq) in the preconceptional human endometrium reveals low risk of infection. WHAT IS KNOWN ALREADY Gene expression datasets from bulk endometrial tissue show no significant expression of the SARS-CoV-2 receptor ACE2 and TMPRSS2. This is in contrast to reported expression of ACE2 at the…
The viral chemokine MCK-2 of murine cytomegalovirus promotes infection as part of a gH/gL/MCK-2 complex.
2013
Human cytomegalovirus (HCMV) forms two gH/gL glycoprotein complexes, gH/gL/gO and gH/gL/pUL(128,130,131A), which determine the tropism, the entry pathways and the mode of spread of the virus. For murine cytomegalovirus (MCMV), which serves as a model for HCMV, a gH/gL/gO complex functionally homologous to the HCMV gH/gL/gO complex has been described. Knock-out of MCMV gO does impair, but not abolish, virus spread indicating that also MCMV might form an alternative gH/gL complex. Here, we show that the MCMV CC chemokine MCK-2 forms a complex with the glycoprotein gH, a complex which is incorporated into the virion. We could additionally show that mutants lacking both, gO and MCK-2 are not ab…
Enzyme-responsive silica mesoporous supports capped with azopyridinium salts for controlled delivery applications
2012
11 páginas, 7 figuras, 3 tablas y 2 esquemas
Enhanced antifungal efficacy of tebuconazole using gated pH-driven mesoporous nanoparticles
2014
Núria Mas,1–3 Irene Galiana,3 Silvia Hurtado,† Laura Mondragón,1–3 Andrea Bernardos,1–3 Félix Sancenón,1–3 María D Marcos,1–3 Pedro Amorós,4 Nuria Abril-Utrillas,5 Ramón Martínez-Máñez,1–3 José Ramón Murguía1,3 1Centro de Reconocimiento Molecular y Desarrollo Tecnológico (IDM), Centro Mixto Universidad Politécnica de Valencia, Universidad de Valencia, Valencia, Spain; 2Departamento de Química, Universidad Politécnica de Valencia, Valenci…
Cell uptake enhancement of folate targeted polymer coated magnetic nanoparticles.
2013
Dual targeted drug delivery systems represent a potential platform for developing efficient vector to tumor sites. In this study we evaluated a folate- and magnetic-targeted nanocarriers based on 10 nm iron oxide nanodomais coated with the properly synthesized and characterized folic acid (FA)-functionalized amphiphilic copolymer PHEA-PLA-PEG-FA. FA was chemically conjugated to one end of diamino-polyethylene glycol of 2000 Da, in order to ensure its exposition on the polymer coated magnetic nanoparticles (MNPs-FA). The prepared nanoparticles have been exhaustively characterized by different methods, including DLS, SEM, FT-IR and magnetic measurements. Magnetic nanoparticles showed dimensio…