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1.

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:

2.

001-es BibID:BIBFORM004633
035-os BibID:(scopus)0344447088 (wos)000074651400008
Első szerző:Nagy Péter (biofizikus)
Cím:Intensity-based energy transfer measurements in digital imaging microscopy / Nagy P., Vamosi G., Bodnar A., Lockett S. J., Szollosi J.
Dátum:1998
ISSN:175-7571
Megjegyzések:Investigation of protein-protein associations is important in understanding structure and function relationships in living cells. Using Forster-type resonance energy transfer between donor and acceptor labeled monoclonal antibodies we can assess the cell surface topology of membrane proteins against which the antibodies were raised. In our current work we elaborated a quantitative image microscopic technique based on the measurement of fluorescence intensities to calculate the energy transfer efficiency on a pixel-by-pixel basis. We made use of the broad excitation and emission spectrum of cellular autofluorescence for background correction of images. In addition to the reference autofluorescence images (UV background) we recorded three fluorescent images (donor, acceptor and energy transfer signal) of donor-acceptor double labeled samples, and corrected for spectral spillage of the directly excited donor and acceptor fluorescence into the energy transfer image. After careful image registration we were able to calculate the energy transfer efficiency on a pixel-by -pixel basis. In this paper, we also present a critical comparison between results obtained with this method and other approaches (photobleaching and flow cytometric energy transfer measurements)
Tárgyszavak:Orvostudományok Elméleti orvostudományok idegen nyelvű folyóiratközlemény külföldi lapban
folyóiratcikk
Antibodies
Antibodies, Monoclonal
Biophysics
Cell Line
chemistry
Comparative Study
Energy Transfer
Fluorescence
Human
Hungary
Image Processing, Computer-Assisted
immunology
Membrane Proteins
methods
Microscopy
Microscopy, Fluorescence
Models, Theoretical
Proteins
Signal Processing,Computer-Assisted
Spectrometry, Fluorescence
statistics and numerical data
Support, Non-U.S.Gov't
Megjelenés:European Biophysics Journal. - 27 : 4 (1998), p. 377-389. -
További szerzők:Vámosi György (1967-) (biofizikus) Dóczy-Bodnár Andrea (1970-) (biofizikus) Lockett, Steven J. Szöllősi János (1953-) (biofizikus)
Internet cím:elektronikus változat
Borító:

3.

001-es BibID:BIBFORM004634
035-os BibID:(scopus)0032101894 (wos)000073937700007
Első szerző:Nagy Péter (biofizikus)
Cím:EGF-induced redistribution of erbB2 on breast tumor cells : flow and image cytometric energy transfer measurements / Nagy, P., Bene, L., Balazs, M., Hyun, W. C., Lockett, S. J., Chiang, N. Y., Waldman, F., Feuerstein, B. G., Damjanovich, S., Szollosi, J.
Dátum:1998
Megjegyzések:erbB2, a member of the epidermal growth factor (EGF) receptor-type tyrosine kinase receptor family, is overexpressed in breast carcinomas with poor prognosis. We examined the cell surface association of this receptor with itself and with other cell surface proteins by the Forster-type fluorescence resonance energy transfer using whole antibodies and Fab fragments. We found that erbB2 molecules homoassociate in unstimulated SK-BR-3, BT474 and BT474-M (a metastatic version of the parent BT474 line) breast tumor cells, and that the interaction was enhanced by EGF treatment in suspensions of SK-BR-3 and BT474-M cells. BT474 cells (with low EGF receptor expression) and attached SK-BR-3 cells do not respond to EGF. Image microscopic energy transfer measurements found considerable pixel-by-pixel heterogeneity in the homoassociation state of erbB2. In accordance with the EGF-induced redistribution of erbB2, EGF receptor was found to be in close proximity to erbB2 in FRET measurements. By labeling different epitopes on erbB2 and the lipid bilayer, we were able to prepare an epitope map of erbB2 molecule. Our data suggest the existence of dynamic cell surface patterns of erbB2 and point to functions fulfilled by these molecular complexes.
Tárgyszavak:Orvostudományok Elméleti orvostudományok idegen nyelvű folyóiratközlemény külföldi lapban
folyóiratcikk
analysis
biosynthesis
Breast Neoplasms
Carcinoma
Cell Membrane
chemistry
drug effects
Energy Transfer
Epidermal Growth Factor
Female
Flow Cytometry
Fluorescence
Human
Hungary
metabolism
methods
Models
Molecular
pharmacology
Receptor
erbB-2
Receptors
Transferrin
Support
Non-U.S.Gov't
Tumor Cells,Cultured
Squamous Cell
ultrastructure
Megjelenés:Cytometry. - 32 : 2 (1998), p. 120-131. -
További szerzők:Bene László (1963-) (biofizikus) Balázs Margit (1952-) (sejtbiológus, molekuláris genetikus) Hyun, William C. Lockett, Steven J. Chiang, Nancy Y. Waldman, Frederick Feuerstein, Burt G. Damjanovich Sándor (1936-2017) (biofizikus) Szöllősi János (1953-) (biofizikus)
Internet cím:elektronikus változat
DOI
Borító:

4.

001-es BibID:BIBFORM046284
Első szerző:Szöllősi János (biofizikus)
Cím:Autofluorescence correction for fluorescence in situ hybridization / Szollosi J., Lockett S. J., Balazs M., Waldman F. M.
Dátum:1995
ISSN:0196-4763
Megjegyzések:Optimal sensitivity of fluorescence in situ hybridization (FISH) requires bright signals and low background fluorescence. Use of locus-specific probes is especially dependent on high sensitivity. Some tissue preparations show high autofluorescence, masking small or dim signals. We have developed a new method for subtracting autofluorescence from digital images on a pixel-by-pixel basis. It is based on the observation that fluorescent labels for FISH have narrower excitation and emission spectra than the chemical components responsible for autofluorescence. Our new approach uses calculation of the ratio of autofluorescence between multiple color images for correction of autofluorescence in each individual image. By subtracting autofluorescence components, we were able to enhance centromeric signals and make previously indistinguishable cosmid signals clearly visible. This image-processing approach to autofluorescence correction may widen the applicability of gene-specific probes in FISH analysis of tumor material.
Tárgyszavak:Orvostudományok Elméleti orvostudományok idegen nyelvű folyóiratközlemény külföldi lapban
Megjelenés:Cytometry. - 20 : 4 (1995), p. 356-361. -
További szerzők:Lockett, Steven J. Balázs Margit (1952-) (sejtbiológus, molekuláris genetikus) Waldman, Frederick
Internet cím:Intézményi repozitóriumban (DEA) tárolt változat
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