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1.

001-es BibID:BIBFORM023492
Első szerző:Matkó János (biológus)
Cím:Analysis of cell surface molecular distributions and cellular signaling by flow cytometry / J. Matkó, L. Mátyus, J. Szöllősi, L. Bene, A. Jenei, P. Nagy, A. Bodnár, S. Damjanovich
Dátum:1994
ISSN:1053-0509
Megjegyzések:Flow cytometry is a fast analysis and separation method for large cell populations, based on collection and processing of optical signals gained on a cell-by-cell basis. These optical signals are scattered light and fluorescence. Owing to its unique potential ofStatistical data analysis and sensitive monitoring of (micro)heterogeneities in large cell populations, flow cytometry?in combination with microscopic imaging techniques?is a powerful tool to study molecular details of cellular signal transduction processes as well. The method also has a widespread clinical application, mostly in analysis of lymphocyte subpopulations for diagnostic (or research) purposes in diseases related to the immune system. A special application of flow cytometry is the mapping of molecular interactions (proximity relationships between membrane proteins) at the cell surface, on a cell-by-cell basis. We developed two approaches to study such questions; both are based ondistance-dependent quenching of excited state fluorophores (donors) by fluorescent or dark (nitroxide radical) acceptors via Förstertype dipole-dipole resonance energy transfer (FRET) and long-range electron transfer (LRET) mechanisms, respectively. A critical evaluation of these methods using donor- or acceptor-conjugated monoclonal antibodies (or their Fab fragments) to select the appropriate cell surface receptor or antigen will be presented in comparison with other approaches for similar purposes. The applicability of FRET and LRET for two-dimensional antigen mapping as well as for detection of conformational changes in extracellular domains of membrane-bound proteins is discussed and illustrated by examples of several lymphoma cell lines. Another special application area of flow cytometry is the analysis of different aspects of cellular signal transduction, e.g., changes of intracellular ion (Ca2+, H+, Na+) concentrations, regulation of ion channel activities, or more complex physiological responses of cell to external stimuli via correlated fluorescence and scatter signal analysis, on a cell-by-cell basis. This way different signaling events such as changes in membrane permeability, membrane potential, cell size and shape, ion distribution, cell density, chromatin structure, etc., can be easily and quickly monitored over large cell populations with the advantage of revealing microheterogeneities in the cellular responses. Flow cytometry also offers the possibility to follow the kinetics of slow (minute- and hour-scale) biological processes in cell populations. These applications are illustrated by the example of complex flow cytometric analysis of signaling in extracellular ATP-triggered apoptosis (programmed cell death) of murine thymic lymphocytes.
Tárgyszavak:Orvostudományok Elméleti orvostudományok idegen nyelvű folyóiratközlemény külföldi lapban
fluorescence
flow cytometry
energy transfer
electron transfer
protein-protein interaction
signal transduction
egyetemen (Magyarországon) készült közlemény
Megjelenés:Journal Of Fluorescence 4 : 4 (1994), p. 303-314. -
További szerzők:Mátyus László (1956-) (biofizikus) Szöllősi János (1953-) (biofizikus) Bene László (1963-) (biofizikus) Jenei Attila (1966-) (biofizikus) Nagy Péter (1971-) (biofizikus) Dóczy-Bodnár Andrea (1970-) (biofizikus) Damjanovich Sándor (1936-2017) (biofizikus)
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DOI
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2.

001-es BibID:BIBFORM038405
Első szerző:Módis László (szemész szakorvos, kontaktológus)
Cím:Új vizsgálómódszer a szemészeti alapkutatásban: az atomerő-mikroszkópia / Módis L., Nagy P., Bistey T., Jenei A.
Dátum:2000
ISSN:0039-8101
Tárgyszavak:Orvostudományok Klinikai orvostudományok magyar nyelvű folyóiratközlemény hazai lapban
Megjelenés:Szemészet. - 137 : 4 (2000), p. 197-200. -
További szerzők:Nagy Péter (1971-) (biofizikus) Bistey Tamás (1973-) (egyetemi tanársegéd, fogszakorvos) Jenei Attila (1966-) (biofizikus)
Internet cím:Intézményi repozitóriumban (DEA) tárolt változat
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3.

001-es BibID:BIBFORM046282
Első szerző:Nagy Péter (biofizikus)
Cím:Ion-channel activities regulate transmembrane signaling in thymocyte apoptosis and T-cell activation / Nagy Péter, Panyi György, Jenei Attila, Bene László, Gáspár Rezső, Matkó János, Damjanovich Sándor
Dátum:1995
ISSN:0165-2478
Megjegyzések:Several examples have shown that plasma membrane ion channels (e.g., Ca2+ and K+ channels) make an important contribution to lymphocyte activation or thymocyte apoptosis. Here we report on the importance of these ion channels in the sensitivity or resistance of lymphoid cells to extracellular ATP-induced apoptosis. Thymocytes of Balb/c mice responded to extracellular ATP (ATPex) sensitively, with an immediate increase in the intracellular calcium level and later with an increased membrane permeability to low MW markers. Mature (medullary) thymocytes showed a higher sensitivity than did cortical thymocytes. Three human lymphoma cell lines, including SUPT13, a cell line reported to be sensitive to TcR/CD3 activation-induced apoptosis, showed a high resistance to ATPex action. These observations suggest that maturation/differentiation state-dependent activity or disappearance of early ATP-receptor operated signaling systems (including ion channels) are critical for the cells in developing towards apoptosis. Using the patch-clamp technique we demonstrated that bretylium tosylate (a particular K(+)-channel blocker) known as inhibitor of T-lymphocyte proliferation also influences the single-channel properties of voltage-gated K+ channels through depressing whole-cell K+ currents. This finding is yet another example underlying the importance of K+ channel activity in T-lymphocyte proliferation.
Tárgyszavak:Orvostudományok Elméleti orvostudományok idegen nyelvű folyóiratközlemény külföldi lapban
Megjelenés:Immunology Letters. - 44 : 2-3 (1995), p. 91-95. -
További szerzők:Panyi György (1966-) (biofizikus) Jenei Attila (1966-) (biofizikus) Bene László (1963-) (biofizikus) Gáspár Rezső (1921-2001) (fizikus) Matkó János (1952-) (biológus) Damjanovich Sándor (1936-2017) (biofizikus)
Pályázati támogatás:T14655
OTKA
F13335
OTKA
T6163
OTKA
T6221
OTKA
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DOI
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4.

001-es BibID:BIBFORM044572
Első szerző:Nagy Péter (biofizikus)
Cím:Activation-dependent clustering of the erbB2 receptor tyrosine kinase detected by scanning near-field optical microscopy / Péter Nagy, Attila Jenei, Achim K. Kirsch, János Szöllősi, Sándor Damjanovich, Thomas M. Jovin
Dátum:1999
Megjegyzések:ErbB2 (HER2, Neu), a member of the epidermal growth factor (EGF) receptor tyrosine kinase family, is often overexpressed in breast cancer and other malignancies. ErbB2 homodimerizes but also presents as a common auxiliary subunit of the EGF and heregulin receptors (erbB1 or EGFR; and erbB3-4, respectively), with which it heteroassociates. ErbB2 is generally regarded as an orphan (ligand-less) receptor with a very potent kinase domain activated either via its associated partners or constitutively as a consequence of discrete mutations. It follows that the extent and regulation of its cell surface interactions are of central importance. We have studied the large-scale association pattern of erbB2 in quiescent and activated cells labeled with fluorescent anti-erbB2 monoclonal antibodies using scanning near-field optical microscopy (SNOM). ErbB2 was found to be concentrated in irregular membrane patches with a mean diameter of approx. 0.5 microm in nonactivated SKBR3 and MDA453 human breast tumor cells. The average number of erbB2 proteins in a single cluster on nonactivated SKBR3 cells was about 10(3). Activation of SKBR3 cells with EGF, heregulin as well as a partially agonistic anti-erbB2 monoclonal antibody led to an increase in the mean cluster diameter to 0.6-0.9 microm, irrespective of the ligand. The EGF-induced increase in the erbB2 cluster size was inhibited by the EGFR-specific tyrosine kinase inhibitor PD153035. The average size of erbB2 clusters on the erbB2-transfected line of CHO cells (CB2) was similar to that of activated SKBR3 cells, a finding correlated with the increased base-line tyrosine phosphorylation of erbB2 in cells expressing only erbB2. We conclude that an increase in cluster size may constitute a general phenomenon in the activation of erbB2.
Tárgyszavak:Orvostudományok Elméleti orvostudományok idegen nyelvű folyóiratközlemény külföldi lapban
Animal
antagonists and inhibitors
chemistry
Cho Cells
Enzyme Activation
Enzyme Inhibitors
Hamsters
Human
metabolism
methods
Microscopy
Microscopy, Atomic Force
Microscopy, Confocal
pharmacology
Quinazolines
Receptor Protein-Tyrosine Kinases
Receptor, Epidermal Growth Factor
Receptor, erbB-2
Support, Non-U.S.Gov't
Tumor Cells, Cultured
egyetemen (Magyarországon) készült közlemény
Megjelenés:Journal of Cell Science 112 : Pt 11 (1999), p. 1733-1741. -
További szerzők:Jenei Attila (1966-) (biofizikus) Kirsch, Achim K. Szöllősi János (1953-) (biofizikus) Damjanovich Sándor (1936-2017) (biofizikus) Jovin, Thomas M.
Internet cím:Intézményi repozitóriumban (DEA) tárolt változat
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5.

001-es BibID:BIBFORM004687
Első szerző:Nagy Péter (biofizikus)
Cím:Cell fusion experiments reveal distinctly different association characteristics of cell-surface receptors / Péter Nagy, László Mátyus, Attila Jenei, György Panyi, Sándor Varga, János Matkó, János Szöllősi, Rezső Gáspár, Thomas M. Jovin, Sándor Damjanovich
Dátum:2001
Megjegyzések:The existence of small- and large-scale membrane protein clusters, containing dimers, oligomers and hundreds of proteins, respectively, has become widely accepted. However, it is largely unknown whether the internal structure of these formations is dynamic or static. Cell fusion was used to perturb the distribution of existing membrane protein clusters, and to investigate their mobility and associations. Scanning near-field optical microscopy, confocal and electron microscopy were applied to detect the exchange of proteins between large-scale protein clusters, whereas photobleaching fluorescence energy transfer was used to image the redistribution of existing small-scale membrane protein clusters. Large-scale clusters of major histocompatibility complex (MHC)-I exchanged proteins with each other and with MHC-II clusters. Similarly to MHC-I, large-scale MHC-II clusters were also dynamic. Exchange of components between small-scale protein clusters was not universal: intermixing did not take place in the case of MHC-II homoclusters; however, it was observed for homoclusters of MHC-I and for heteroclusters of MHC-I and MHC-II. These processes required a fluid state of the plasma membrane, and did not depend on endocytosis-mediated recycling of proteins. The redistribution of large-scale MHC-I clusters precedes the intermixing of small-scale clusters of MHC-I indicating a hierarchy in protein association. Investigation of a set of other proteins (alpha subunit of the interleukin 2 receptor, CD48 and transferrin receptor) suggested that a large-scale protein cluster usually exchanges components with the same type of clusters. These results offer new insight into processes requiring time-dependent changes in membrane protein interactions.
Tárgyszavak:Orvostudományok Elméleti orvostudományok idegen nyelvű folyóiratközlemény külföldi lapban
Biophysics
Cell Fusion
Cell Line
Cell Membrane
chemistry
Dyes
Energy Transfer
Fluorescence
Fluorescent Dyes
Gold Colloid
Histocompatibility Antigens
Histocompatibility Antigens Class I
Histocompatibility Antigens Class II
Human
Hungary
Interleukin-2
Major Histocompatibility Complex
Membrane Microdomains
metabolism
methods
Microscopy
Microscopy,Fluorescence
physiology
Proteins
Receptor Aggregation
Receptors,Cell Surface
Receptors,Interleukin-2
Support,Non-U.S.Gov't
Megjelenés:Journal of Cell Science 114 : Pt 22 (2001), p. 4063-4071. -
További szerzők:Mátyus László (1956-) (biofizikus) Jenei Attila (1966-) (biofizikus) Panyi György (1966-) (biofizikus) Varga Sándor (1943-) (biofizikus) Matkó János (1952-) (biológus) Szöllősi János (1953-) (biofizikus) Gáspár Rezső (1944-) (biofizikus) Jovin, Thomas M. Damjanovich Sándor (1936-2017) (biofizikus)
Internet cím:elektronikus változat
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6.

001-es BibID:BIBFORM004650
035-os BibID:(scopus)0033367737
Első szerző:Nagy Péter (biofizikus)
Cím:Complexity of signal transduction mediated by ErbB2 : clues to the potential of receptor-targeted cancer therapy / Nagy, P., Jenei, A., Damjanovich, S., Jovin, T. M., Szollosi, J.
Dátum:1999
Megjegyzések:The erbB2 oncogene belongs to the type I trans-membrane tyrosine kinase family of receptors. Its medical importance stems from its widespread over-expression in breast cancer. This review will focus on the signal transduction through this protein, and explains how the overexpression of erbB2 may result in poor prognosis of breast cancer, and finally it will summerize our current understanding about the therapeutic potential of receptor-targeted therapy in breast cancer. ErbB2 does not have any known ligand which is able to bind to it with high affinity. However the kinase activity of erbB2 can be activated without any ligand, if it is overexpressed, and by heteroassociation with other members of the erbB family (erbB1 or epidermal growth factor receptor, erbB3 and erbB4). This interaction substantially increases the efficiency and diversity of signal transduction through these receptor complexes. In addition, erbB2 forms large scale receptor clusters containing hundreds of proteins. These receptor islands may take part in recruiting cytosolic factors which relay the signal towards the nucleus or the cytoplasm. Overexpression of erbB2 was linked to higher transforming activity, increased metastatic potential, angiogenesis and drug resistence of breast tumor in laboratory experiments. As a corollary of these properties, erbB2 amplification is generally thought to be associated with a poor prognosis in breast cancer patients. These early findings lead to the development of antibodies that down-regulate erbB2. Such a therapeutic approach has already been found effective in experimental tumor models and in clinical trials as well. Further understanding of the importance of erbB2 and growth factor receptors in the transformation of normal cells to malignant ones may once give us a chance to cure erbB2 over-expressing breast cancer
Tárgyszavak:Orvostudományok Elméleti orvostudományok idegen nyelvű folyóiratközlemény külföldi lapban
folyóiratcikk
Animal
Antibodies, Monoclonal
Antineoplastic Agents
Breast Neoplasms
Cytoplasm
drug therapy
Female
Gene Therapy
Genes, erbB-2
genetics
Human
Hungary
Neoplasms
physiology
Receptor, erbB-2
Signal Transduction
Support, Non-U.S.Gov't
therapeutic use
therapy
egyetemen (Magyarországon) készült közlemény
Megjelenés:Pathology and Oncology Research. - 5 : 4 (1999), p. 255-271. -
További szerzők:Jenei Attila (1966-) (biofizikus) Damjanovich Sándor (1936-2017) (biofizikus) Jovin, Thomas M. Szöllősi János (1953-) (biofizikus)
Internet cím:DOI
elektronikus változat
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7.

001-es BibID:BIBFORM062699
035-os BibID:(scopus)84925853989 (wos)000354040400007
Első szerző:Shrestha, Dilip (biológus)
Cím:Understanding FRET as a Research Tool for Cellular Studies / Dilip Shrestha, Attila Jenei, Péter Nagy, György Vereb, János Szöllősi
Dátum:2015
ISSN:1661-6596 1422-0067
Megjegyzések:Communication of molecular species through dynamic association and/or dissociation at various cellular sites governs biological functions. Understanding these physiological processes require delineation of molecular events occurring at the level of individual complexes in a living cell. Among the few non-invasive approaches with nanometer resolution are methods based on Förster Resonance Energy Transfer (FRET). FRET is effective at a distance of 1?10 nm which is equivalent to the size of macromolecules, thus providing an unprecedented level of detail on molecular interactions. The emergence of fluorescent proteins and SNAP- and CLIP- tag proteins provided FRET with the capability to monitor changes in a molecular complex in real-time making it possible to establish the functional significance of the studied molecules in a native environment. Now, FRET is widely used in biological sciences, including the field of proteomics, signal transduction, diagnostics and drug development to address questions almost unimaginable with biochemical methods and conventional microscopies. However, the underlying physics of FRET often scares biologists. Therefore, in this review, our goal is to introduce FRET to non-physicists in a lucid manner. We will also discuss our contributions to various FRET methodologies based on microscopy and flow cytometry, while describing its application for determining the molecular heterogeneity of the plasma membrane in various cell types.
Tárgyszavak:Orvostudományok Elméleti orvostudományok idegen nyelvű folyóiratközlemény külföldi lapban
folyóiratcikk
FRET
Megjelenés:International Journal Of Molecular Sciences. - 16 : 4 (2015), p. 6718-6756. -
További szerzők:Jenei Attila (1966-) (biofizikus) Nagy Péter (1971-) (biofizikus) Vereb György (1965-) (biofizikus, orvos) Szöllősi János (1953-) (biofizikus)
Pályázati támogatás:MTA-DE
MTA
Sejtbiológiai és Jelátvitel Kutatócsoport
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