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1.

001-es BibID:BIBFORM004856
Első szerző:Bagossi Péter (biokémikus, vegyész)
Cím:Molecular modeling of nearly full-length ErbB2 receptor / Bagossi, P., Horvath, G., Vereb, G., Szollosi, J., Tozser, J.
Dátum:2005
ISSN:0006-3495
Megjegyzések:Members of the epidermal growth factor receptor family play important roles in various cellular processes, both in physiological and in pathological conditions. Dimerization and autophosphorylation of these receptor tyrosine kinases are key events of signal transduction. Details of the molecular events of the signaling are not entirely known. To facilitate the understanding of receptor structure and function at the molecular level, a molecular model was built for the nearly full-length ErbB2 dimer. Modeling was based on the x-ray or nuclear-magnetic resonance structures of extracellular, transmembrane, and intracellular domains. The extracellular domain was positioned above the cell membrane based on the distance determined from experimentally measured fluorescence resonance energy transfer. Favorable dimerization interactions are predicted for the extracellular, transmembrane, and protein kinase domains in the model of a nearly full-length dimer of ErbB2, which may act in a coordinated fashion in ErbB2 homodimerization, and also in heterodimers of ErbB2 with other members of the ErbB family
Tárgyszavak:Orvostudományok Elméleti orvostudományok idegen nyelvű folyóiratközlemény külföldi lapban
analysis
Cell Line, Tumor
Cell Membrane
chemistry
Comparative Study
Computer Simulation
Dimerization
Energy Transfer
Epidermal Growth Factor
Fluorescence
Fluorescence Resonance Energy Transfer
Humans
Hungary
Lipid Bilayers
methods
Models, Chemical
Models, Molecular
Neoplasms
Protein Conformation
Protein Structure, Tertiary
Receptor, erbB-2
Research
Signal Transduction
Structure-Activity Relationship
Support
ultrastructure
Megjelenés:Biophysical Journal. - 88 : 2 (2005), p. 1354-1363. -
További szerzők:Horváth Gábor (1974-) (biofizikus) Vereb György (1965-) (biofizikus, orvos) Szöllősi János (1953-) (biofizikus) Tőzsér József (1959-) (molekuláris biológus, biokémikus, vegyész)
Internet cím:elektronikus változat
Borító:

2.

001-es BibID:BIBFORM004861
035-os BibID:(scopus)14644392200 (wos)000227768400023
Első szerző:Diermeier, Simone
Cím:Epidermal growth factor receptor coexpression modulates susceptibility to Herceptin in HER2/neu overexpressing breast cancer cells via specific erbB-receptor interaction and activation / Diermeier, S., Horvath, G., Knuechel-Clarke, R., Hofstaedter, F., Szollosi, J., Brockhoff, G.
Dátum:2005
ISSN:0014-4827
Megjegyzések:Growth factors and Herceptin specifically and differentially modulate cell proliferation of tumor cells. However, the mechanism of action on erbB-receptor level is incompletely understood. We evaluated Herceptin's capacity to modulate erbB-receptor activation and interaction on the cell surface level and thereby potentially impair cell proliferation of HER2/neu (c-erbB2) overexpressing breast cancer cells, both in the presence and absence of relevant growth factors. METHODS: BT474 and SK-BR-3 breast cancer cell lines were treated with Epidermal Growth Factor (EGF), Heregulin, and with Herceptin in different combinations. Kinetics of cell proliferation were evaluated flow cytometrically based on BrdU-labeling. Fluorescence Resonance Energy Transfer, ELISAs and phosphorylation site specific Western Blotting was performed to investigate erbB-receptor interaction and activation. RESULTS: EGF induced EGFR/EGFR and EGFR/c-erbB2 interactions correlate with stimulation of cell proliferation in BT474 cells. Both homo- and heterodimerization are considerably less pronounced in SK-BR-3 cells and heterointeraction is additionally reduced by EGF treatment, causing inhibition of cell proliferation. Heregulin stimulates cell proliferation extensively in both cell lines. Herceptin drives BT474 cells more efficiently into quiescence than it does with SK-BR-3 cells and thereby blocks cell cycle progress. In SK-BR-3 Herceptin treatment causes c-erbB2 phosphorylation of Y877 and Y1248, EGF induces Y877 and Y1112 phosphorylation. The Y1112 phosphorylation site, activated by EGF in SK-BR-3 cell, is bypassed in BT474. In addition the inhibitory capacity of Herceptin on BT474 and SK-BR-3 cell proliferation depends on the presence and absence of growth factors to a various extent. CONCLUSION: The growth inhibitory effect of Herceptin on c-erbB2 overexpressing breast cancer cells is considerably modulated by EGFR coexpression and consequently EGFR/c-erbB2 homo- and heterointeractions, as well as the presence or absence of growth factors. C-erbB2 overexpression alone is insufficient to predict the impact of growth factors and antibodies on cell proliferation. The optimization and specification of therapeutic approaches based on erbB-receptor targeting requires to account for EGFR coexpression as well as the potential presence of erbB-receptor relevant growth factors.
Tárgyszavak:Orvostudományok Elméleti orvostudományok idegen nyelvű folyóiratközlemény külföldi lapban
folyóiratcikk
Antibodies
Antibodies,Monoclonal
Antineoplastic Agents
Breast Neoplasms
Carcinoma
Cell Cycle
Cell Cycle Proteins
Cell Line
Cell Line, Tumor
Cell Proliferation
Cells
drug effects
Drug Resistance,Neoplasm
Drug Synergism
drug therapy
Energy Transfer
Epidermal Growth Factor
Female
Fluorescence
Fluorescence Resonance Energy Transfer
genetics
Growth Inhibitors
Humans
Kinetics
metabolism
methods
Neuregulin-1
pathology
pharmacology
Phosphorylation
physiology
Proteins
Receptor, Epidermal Growth Factor
Receptor, erbB-2
Receptors, Cell Surface
Research
Support
therapeutic use
Megjelenés:Experimental Cell Research. - 304 : 2 (2005), p. 604-619. -
További szerzők:Horváth Gábor (1974-) (biofizikus) Knuechel-Clarke, Ruth Hofstaedter, Ferdinand Szöllősi János (1953-) (biofizikus) Brockhoff, Gero
Internet cím:elektronikus változat
DOI
Borító:

3.

001-es BibID:BIBFORM050042
035-os BibID:PMID:23504771
Első szerző:Fábián Ákos István (aneszteziológus)
Cím:TripleFRET measurements in flow cytometry / Ákos Fábián, Gábor Horváth, György Vámosi, György Vereb, János Szöllősi
Dátum:2013
Megjegyzések:A frequently used method for viewing protein interactions and conformation, Forster (fluorescence) resonance energy transfer (FRET), has traditionally been restricted to two fluorophores. Lately, several methods have been introduced to expand FRET methods to three species. We present a method that allows the determination of FRET efficiency in three-dye systems on a flow cytometer. TripleFRET accurately reproduces energy transfer efficiency values measured in two-dye systems, and it can indicate the presence of trimeric complexes, which is not possible with conventional FRET methods. We also discuss the interpretation of energy transfer values obtained with tripleFRET in relation to spatial distribution of labeled molecules, specifically addressing the limitations of using total energy transfer to determine molecular distance
Tárgyszavak:Orvostudományok Elméleti orvostudományok idegen nyelvű folyóiratközlemény külföldi lapban
analysis
Antibodies
Antibodies,Monoclonal,Humanized
article
Biophysics
cell biology
Cell Line
chemistry
cytometry
Dyes
Energy Transfer
ENERGY-TRANSFER
FLOW
Flow Cytometry
Fluorescence
Fluorescence Resonance Energy Transfer
fluorescent dye
Fluorescent Dyes
FRET
Humans
Hungary
Immunoconjugates
immunology
methods
Protein Binding
PROTEIN INTERACTIONS
Research
Research Support
resonance energy transfer
Staining and Labeling
statistics & numerical data
Support
Megjelenés:Cytometry Part A. - 83 : 4 (2013), p. 375-385. -
További szerzők:Horváth Gábor (1974-) (biofizikus) Vámosi György (1967-) (biofizikus) Vereb György (1965-) (biofizikus, orvos) Szöllősi János (1953-) (biofizikus)
Pályázati támogatás:NK 101337
OTKA
K75752
OTKA
TÁMOP-4.2.2-08/1-2008-0019
TÁMOP
TÁMOP-4.2.1/B-09/1/KONV-2010-0007
TÁMOP
Receptor tirozin kinázok mint terápiás célpontok : működésük szabályozásának, és a közöttük fellépő molekuláris kölcsönhatások vizsgálata
TÁMOP-4.2.2.A-11/1/KONV-2012-0025
TÁMOP
Baross Gábor Program REG_EA_09-1-2009-0010
Egyéb
K77600
OTKA
K103965
OTKA
Internet cím:DOI
Intézményi repozitóriumban (DEA) tárolt változat
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4.

001-es BibID:BIBFORM042654
035-os BibID:(scopus)19444380683 (wos)000229353200007
Első szerző:Horváth Gábor (biofizikus)
Cím:Selecting the right fluorophores and flow cytometer for fluorescence resonance energy transfer measurements / Gábor Horváth, Miklós Petrás, Gergely Szentesi, Ákos Fábián, John W. Park, György Vereb, János Szöllősi
Dátum:2005
ISSN:1552-4922 1552-4930
Megjegyzések:BACKGROUND:Fluorescence resonance energy transfer applied in flow cytometry (FCET) is an excellent tool for determining supramolecular organization of biomolecules at the cell surface or inside the cell. Availability of new fluorophores and cytometers requires the establishment of fluorophore dye pairs most suitable for FCET measurements.METHODS:A gastric tumor cell line (N87) was labeled for major histocompatibility complex class I heavy chain and beta2-microglobulin with antibodies conjugated with fluorescein- and indocarbocyanine-like fluorophores and analyzed in FCET measurements on a cell-by-cell basis using three flow cytometers: FACSCalibur, FACSDiVa, and FACSArray.RESULTS:Normalized fluorescence intensity values were measured and normalized energy transfer efficiencies, spectral overlap integrals, and crucial dye- and instrument-dependent parameters were calculated for all matching pairs of seven fluorophores on the three commercial cytometers. The most crucial parameter in determining the applicability of the donor-acceptor pairs was the normalized fluorescence intensity and the least important one was the spectral overlap.CONCLUSIONS:On the basis of available laser lines, the optimal dye pair for all three cytometers is the Alexa546-Alexa647 pair, which produces high energy transfer efficiency values and has the best spectral characteristics with regard to laser excitation, detection of emission, and spectral overlap.
Tárgyszavak:Orvostudományok Elméleti orvostudományok idegen nyelvű folyóiratközlemény külföldi lapban
folyóiratcikk
fluorescence resonance energy transfer
flow cytometry
donor-acceptor pair
egyetemen (magyarországon) készült közlemény
Megjelenés:Cytometry. Part A. - 65A : 2 (2005), p. 148-157. -
További szerzők:Petrás Miklós (1977-) (orvos) Szentesi Gergely (1976-) (kémia-fizika tanár) Fábián Ákos István (1982-) (aneszteziológus) Park, John W. Vereb György (1965-) (biofizikus, orvos) Szöllősi János (1953-) (biofizikus)
Internet cím:Szerző által megadott URL
DOI
Intézményi repozitóriumban (DEA) tárolt változat
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5.

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:

6.

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:

7.

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:

8.

001-es BibID:BIBFORM004846
035-os BibID:(scopus)3242784810 (wos)000223353700003
Első szerző:Szentesi Gergely (kémia-fizika tanár)
Cím:Computer program for determining fluorescence resonance energy transfer efficiency from flow cytometric data on a cell-by-cell basis / Szentesi, G., Horvath, G., Bori, I., Vamosi, G., Szollosi, J., Gaspar, R., Damjanovich, S., Jenei, A., Matyus, L.
Dátum:2004
Megjegyzések:The determination of fluorescence resonance energy transfer (FRET) with flow cytometry (FCET) is one of the most efficient tools to study the proximity relationships of cell membrane components in cell populations on a cell-by-cell basis. Because of the high amount of data and the relatively tedious calculations, this procedure should be assisted by powerful data processing software. The currently available programs are not able to fulfill this requirement. We developed a Windows-based program to calculate fluorescence resonance energy transfer efficiency values from list mode flow cytometry standard (FCS) files. This program displays the measured data in standard plots by generating one- and two-parameter histograms on linear or logarithmic scales. A graphical gating tool allows the user to select the desired cell population according to any combination of the parameter values. The program performs several statistical calculations, including mean, S.D., percent of the gated data. We have implemented two types of data sheet for FRET calculations to aid and guide the user during the analysis: one with population-mean-based autofluorescence correction and the other with spectrum-based cell-by-cell autofluorescence correction. In this paper, we describe the gating algorithms, the file opening procedure and the rules of gating. The structure of the program and a short description of the graphical user-interface (GUI) are also presented in this article.
Tárgyszavak:Orvostudományok Elméleti orvostudományok idegen nyelvű folyóiratközlemény külföldi lapban
folyóiratcikk
Algorithms
analysis
Biophysics
Cell Membrane
Computer Simulation
Energy Transfer
Flow Cytometry
Fluorescence
Fluorescence Resonance Energy Transfer
Humans
Hungary
methods
Research
Software
Support
egyetemen (Magyarországon) készült közlemény
Megjelenés:Computer Methods and Programs in Biomedicine. - 75 : 3 (2004), p. 201-211. -
További szerzők:Horváth Gábor (1974-) (biofizikus) Bori Imre (1929-2004) Vámosi György (1967-) (biofizikus) Szöllősi János (1953-) (biofizikus) Gáspár Rezső (1944-) (biofizikus) Damjanovich Sándor (1936-2017) (biofizikus) Jenei Attila (1966-) (biofizikus) Mátyus László (1956-) (biofizikus)
Internet cím:elektronikus változat
DOI
Borító:

9.

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:
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