Találati lista | Tudóstér

001-es BibID:	BIBFORM004713
035-os BibID:	(scopus)0037112996 (wos)000179662300005
Első szerző:	Nagy Péter (biofizikus)
Cím:	Lipid rafts and the local density of ErbB proteins influence the biological role of homo- and heteroassociations of ErbB2 / Nagy, P., Vereb, G., Sebestyen, Z., Horvath, G., Lockett, S. J., Damjanovich, S., Park, J. W., Jovin, T. M., Szollosi, J.
Dátum:	2002
Megjegyzések:	The ErbB family of transmembrane receptor tyrosine kinases plays an important role in the pathogenesis of many cancers. The four members of the family, ErbB1-4, form various homo- and heterodimers during the course of signal transduction. A second hierarchical level of molecular associations involving 10(2)-10(3) molecules, termed large-scale clustering, has also been identified, but the regulatory factors and biological consequences of such structures have not been systematically evaluated. In this report, we describe the states of association of ErbB2 and their relationship to local ErbB3 density and lipid rafts based on quantitative fluorescence microscopy of SKBR-3 breast cancer cells. Clusters of ErbB2 colocalized with lipid rafts identified by the GM1-binding B subunit of cholera toxin. Pixel-by-pixel analysis of fluorescence resonance energy transfer between labeled antibodies indicated that the homoassociation (homodimerization) of ErbB2 was proportional to the local density of ErbB2 and inversely proportional to that of ErbB3 and of the raft-specific lipid GM1. Crosslinking lipid rafts with the B subunit of cholera toxin caused dissociation of the rafts and ErbB2 clusters, an effect that was independent of the cytoskeletal anchoring of ErbB2. Crosslinking also decreased ErbB2-ErbB3 heteroassociation and the EGF- and heregulin-induced tyrosine phosphorylation of Shc. When cells were treated with the anti-ErbB2 monoclonal antibody 4D5 (parent murine version of Trastuzumab used in the immunotherapy of breast cancer), internalization of the antibody was inhibited by crosslinking of lipid rafts, but the antiproliferative activity of 4D5 was retained and even enhanced. We conclude that local densities of ErbB2 and ErbB3, as well as the lipid environment profoundly influence the association properties and biological function of ErbB2.
Tárgyszavak:	Orvostudományok Elméleti orvostudományok idegen nyelvű folyóiratközlemény külföldi lapban folyóiratcikk Adaptor Proteins,Signal Transducing Adaptor Proteins,Vesicular Transport analysis Antibodies Antibodies,Monoclonal Antineoplastic Agents Biophysics Breast Neoplasms Carcinoma Cell Division Cell Membrane Cell Transformation,Neoplastic Cells Cholera Toxin Cytoskeletal Proteins Dimerization drug effects Energy Transfer Eukaryotic Cells Female Fluorescence Fluorescence Resonance Energy Transfer genetics Humans Hungary Macromolecular Substances Membrane Microdomains metabolism Microscopy Oncogene Proteins v-erbB pharmacology Phosphorylation physiology Protein Binding Protein-Tyrosine Kinases Proteins Receptor Protein-Tyrosine Kinases Receptor,erbB-2 Receptor,erbB-3 Receptors,Cell Surface Research Signal Transduction Support Tumor Cells,Cultured ultrastructure
Megjelenés:	Journal of Cell Science. - 115 : Pt 22 (2002), p. 4251-4262. -
További szerzők:	Vereb György (1965-) (biofizikus, orvos) Sebestyén Zsolt Horváth Gábor (1974-) (biofizikus) Lockett, Steven J. Damjanovich Sándor (1936-2017) (biofizikus) Park, John W. Jovin, Thomas M. Szöllősi János (1953-) (biofizikus)
Internet cím:	elektronikus változat elektronikus változat
Borító:
Saját polcon:

001-es BibID:	BIBFORM012845
Első szerző:	Nagyné Szabó Ágnes Timea (vegyész)
Cím:	Quantitative Characterization of the Large-Scale Association of ErbB1 and ErbB2 by Flow Cytometric Homo-FRET Measurements? / Szabó A., Horváth G., Szöllősi J., Nagy P.
Dátum:	2008
ISSN:	0006-3495
Megjegyzések:	The association of receptor tyrosine kinases is a key step in the initiation of growth factor-mediated signaling. Although the ligand-induced dimerization of inactive, monomeric receptors was the central dogma of receptor tyrosine kinase activation for decades, the existence of larger oligomers is now accepted. Both homoassociations and heteroassociations are of extreme importance in the epidermal growth factor (EGF) receptor family, leading to diverse and robust signaling. We present a statistically reliable, flow-cytometric homo-fluorescence resonance energy transfer method for the quantitative characterization of large-scale receptor clusters. We assumed that a fraction of a certain protein species is monomeric, whereas the rest are present in homoclusters of N-mers. We measured fluorescence anisotropy as a function of the saturation of fluorescent antibody binding, and fitted the model to the anisotropy data yielding the fraction of monomers and the cluster size. We found that ErbB2 formed larger homoclusters than ErbB1. Stimulation with EGF and heregulin led to a decrease in ErbB2 homocluster size, whereas ErbB1 homoclusters became larger after EGF stimulation. The activation level of ErbB2 was inversely proportional to its homocluster size. We conclude that homoclusters of ErbB1 and ErbB2 behave in a fundamentally different way. Whereas huge ErbB2 clusters serve as a reservoir of inactive coreceptors and dissociate upon stimulation, small ErbB1 homoclusters form higher-order oligomers after ligand binding.
Tárgyszavak:	Orvostudományok Elméleti orvostudományok idegen nyelvű folyóiratközlemény külföldi lapban folyóiratcikk
Megjelenés:	Biophysical Journal. - 95 : 4 (2008), p. 2086-2096. -
További szerzők:	Horváth Gábor (1974-) (biofizikus) Szöllősi János (1953-) (biofizikus) Nagy Péter (1971-) (biofizikus)
Internet cím:	Szerző által megadott URL DOI Intézményi repozitóriumban (DEA) tárolt változat
Borító:
Saját polcon:

001-es BibID:	BIBFORM039658
035-os BibID:	(scopus)0036628631 (wos)000176656500002
Első szerző:	Sebestyén Zsolt
Cím:	Long wavelength fluorophores and cell-by-cell correction for autofluorescence significantly improves the accuracy of flow cytometric energy transfer measurements on a dual-laser benchtop flow cytometer / Zsolt Sebestyén, Péter Nagy, Gábor Horváth, György Vámosi, Reno Debets, Jan W. Gratama, Denis R. Alexander, János Szöllősi
Dátum:	2002
ISSN:	0196-4763
Megjegyzések:	Flow cytometric fluorescence resonance energy transfer (FCET) is an efficient method to map associations between biomolecules because of its high sensitivity to changes in molecular distances in the range of 1-10 nm. However, the requirement for a dual-laser instrument and the need for a relatively high signal-to-noise system (i.e., high expression level of the molecules) pose limitations to a wide application of the method.METHODS:Antibodies conjugated to cyanines 3 and 5 (Cy3 and Cy5) were used to label membrane proteins on the cell surface. FCET measurements were made on a widely used benchtop dual-laser flow cytometer, the FACSCalibur, by using cell-by-cell analysis of energy transfer efficiency.ResultsTo increase the accuracy of FCET measurements, we applied a long wavelength donor-acceptor pair, Cy3 and Cy5, which beneficially affected the signal-to-noise ratio in comparison with the classic pair of fluorescein and rhodamine. A new algorithm for cell-by-cell correction of autofluorescence further improved the sensitivity of the technique; cell subpopulations with only slightly different FCET efficiencies could be identified. The new FCET technique was tested on various direct and indirect immunofluorescent labeling strategies. The highest FCET values could be measured when applying direct labeling on both (donor and acceptor) sides. Upon increasing the complexity of the labeling scheme by introducing secondary antibodies, we detected a decrease in the energy transfer efficiency.CONCLUSIONS:We developed a new FCET protocol by applying long wavelength excitation and detection of fluorescence and by refining autofluorescence correction. The increased accuracy of the new method makes cells with low receptor expression amenable to FCET investigation, and the new approach can be implemented easily on a commercially available dual-laser flow cytometer, such as a FACSCalibur.
Tárgyszavak:	Orvostudományok Elméleti orvostudományok idegen nyelvű folyóiratközlemény külföldi lapban folyóiratcikk Algorithms analysis Antibodies Biophysics Calibration Cell Line, Transformed Cells Comparative Study Dyes Energy Transfer Flow Cytometry Fluorescein Fluorescence Fluorescence Resonance Energy Transfer Fluorescent Dyes Humans Hungary instrumentation Lasers Membrane Proteins methods Proteins Reproducibility of Results Research Spectrometry, Fluorescence Subtraction Technique Support Tumor Cells, Cultured egyetemen (Magyarországon) készült közlemény
Megjelenés:	Cytometry. - 48 : 3 (2002), p. 124-135. -
További szerzők:	Nagy Péter (1971-) (biofizikus) Horváth Gábor (1974-) (biofizikus) Vámosi György (1967-) (biofizikus) Debets, Reno Gratama, Jan Willem Alexander, Denis R. Szöllősi János (1953-) (biofizikus)
Internet cím:	Szerző által megadott URL DOI Intézményi repozitóriumban (DEA) tárolt változat
Borító:
Saját polcon:

001-es BibID:	BIBFORM073588
Első szerző:	Szöllősi János (biofizikus)
Cím:	Új fluoreszcens jelzők a citometriában = Novel fluorescent markers in cytometry / Szöllősi János, Horváth Gábor, Nagy Péter, Vereb György
Dátum:	2004
Tárgyszavak:	Orvostudományok Elméleti orvostudományok könyvfejezet citometria
Megjelenés:	Modern sejtanalitikai módszerek : a IV. Magyar Sejtanalitikai Konferencia kiadványa / Szerk. Vereb György Jr., Szöllősi János, Molnár B. - p. 57-60. -
További szerzők:	Horváth Gábor (1974-) (biofizikus) Nagy Péter (1971-) (biofizikus) Vereb György (1965-) (biofizikus, orvos)
Borító:
Saját polcon: