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001-es BibID:BIBFORM065104
035-os BibID:(WoS)000380371400013 (Scopus)84993661764
Első szerző:Mocsár Gábor (biofizikus)
Cím:MHC I expression regulates co-clustering and mobility of interleukin-2 and -15 receptors in T cells / G. Mocsár, J. Volkó, D. Rönnlund, J. Widengren, P. Nagy, J. Szöllősi, K. Tóth, C. K. Goldman, S. Damjanovich, T. A. Waldmann, A. Bodnár, G. Vámosi
Dátum:2016
ISSN:0006-3495
Megjegyzések:MHC glycoproteins form supramolecular clusters with interleukin-2 and -15 receptors in lipid rafts of T cells.The role of highly expressed MHC I in maintaining these clusters is unknown. We knocked down MHC I inFT7.10 human T cells, and studied protein clustering at two hierarchic levels: molecular aggregations andmobility by FRET and fluorescence correlation spectroscopy, and segregation into larger domains orsuperclusters by superresolution STED microscopy. FCS based molecular brightness analysis revealed thatthe studied molecules diffused as tight aggregates of several proteins of a kind. Knockdown reduced thenumber of MHC I containing molecular aggregates and their average MHC I content, and decreased theheteroassociation of MHC I with IL-2R?/IL-15R?. The mobility of not only MHC I but also that of IL-2R?/IL-15R? increased, corroborating the general size decrease of tight aggregates. A multifaceted analysis of STEDimages revealed that the diameter of MHC I superclusters diminished from 400-600 to 200-300 nm, whereasthose of IL-2R?/IL-15R? hardly changed. MHC I and IL-2R?/IL-15R? colocalized with GM1 gangliosiderichlipid rafts, but MHC I clusters retracted to smaller subsets of GM1- and IL-2R?/IL-15R?-rich areas uponknockdown. Our results prove that changes in expression level may significantly alter the organization andmobility of interacting membrane proteins.
Tárgyszavak:Orvostudományok Elméleti orvostudományok idegen nyelvű folyóiratközlemény külföldi lapban
folyóiratcikk
Megjelenés:Biophysical Journal. - 111 : 1 (2016), p. 100-112. -
További szerzők:Volkó Julianna (1983-) (biotechnológus) Rönnlund, Daniel Widengren, Jerker Nagy Péter (1971-) (biofizikus) Szöllősi János (1953-) (biofizikus) Tóth Katalin (Heidelberg) Goldman, Caroline K. Damjanovich Sándor (1936-2017) (biofizikus) Waldmann, Thomas A. Dóczy-Bodnár Andrea (1970-) (biofizikus) Vámosi György (1967-) (biofizikus)
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2.

001-es BibID:BIBFORM072316
035-os BibID:(WoS)000425895600022 (Scopus)85041571964
Első szerző:Nagyné Szabó Ágnes Timea (vegyész)
Cím:The Effect of Fluorophore Conjugation on Antibody Affinity and the Photophysical Properties of Dyes / Szabó Ágnes, Szendi-Szatmári Tímea, Ujlaky-Nagy László, Rádi Ildikó, Vereb György, Szöllősi János, Nagy Peter
Dátum:2018
ISSN:0006-3495
Megjegyzések:Because the degree of labeling (DOL) of cell-bound antibodies, often required in quantitative fluorescence measurements, is largely unknown, we investigated the effect of labeling with two different fluorophores (AlexaFluor546, AlexaFluor647) in a systematic way using antibody stock solutions with different DOLs. Here, we show that the mean DOL of the cell-bound antibody fraction is lower than that of the stock using single molecule fluorescence measurements. The effect is so pronounced that the mean DOL levels off at approximately two fluorophores/IgG for some antibodies. We developed a method for comparing the average DOL of antibody stocks to that of the isolated, cell-bound fraction based on fluorescence anisotropy measurements confirming the aforementioned conclusions. We created a model in which individual antibody species with different DOLs, present in an antibody stock solution, were assumed to have distinct affinities and quantum yields. The model calculations confirmed that a calibration curve constructed from the anisotropy of antibody stocks can be used for determining the DOL of the bound fraction. The fluorescence intensity of the cell-bound antibody fractions and of the antibody stocks exhibited distinctly different dependence on the DOL. The behavior of the two dyes was systematically different in this respect. Fitting of the model to these data revealed that labeling with each dye affects quantum yield and antibody affinity differentially. These measurements also implied that fluorophores in multiply labeled antibodies exhibit self-quenching and lead to decreased antibody affinity, conclusions directly confirmed by steady-state intensity measurements and competitive binding assays. Although the fluorescence lifetime of antibodies labeled with multiple fluorophores decreased, the magnitude of this change was not sufficient to account for self-quenching indicating that both dynamic and static quenching processes occur involving H-aggregate formation. Our results reveal multiple effects of fluorophore conjugation, which must not be overlooked in quantitative cell biological measurements.
Tárgyszavak:Természettudományok Biológiai tudományok idegen nyelvű folyóiratközlemény külföldi lapban
folyóiratcikk
Megjelenés:Biophysical Journal. - 114 : 3 (2018), p. 688-700. -
További szerzők:Szendi-Szatmári Tímea (1989-) (molekuláris biológus) Ujlaky-Nagy László (1977-) (biofizikus) Rádi Ildikó Vereb György (1965-) (biofizikus, orvos) Szöllősi János (1953-) (biofizikus) Nagy Péter (1971-) (biofizikus)
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3.

001-es BibID:BIBFORM012846
Első szerző:Nagyné Szabó Ágnes Timea (vegyész)
Cím:Coclustering of ErbB1 and ErbB2 Revealed by FRET-Sensitized Acceptor Bleaching / Szabó Ágnes, Szöllősi János, Nagy Péter
Dátum:2010
ISSN:0006-3495
Tárgyszavak:Orvostudományok Elméleti orvostudományok idegen nyelvű folyóiratközlemény külföldi lapban
Megjelenés:Biophysical Journal. - 99 : 1 (2010), p. 105-114. -
További szerzők:Szöllősi János (1953-) (biofizikus) Nagy Péter (1971-) (biofizikus)
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Intézményi repozitóriumban (DEA) tárolt változat
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4.

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)
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Intézményi repozitóriumban (DEA) tárolt változat
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5.

001-es BibID:BIBFORM082149
035-os BibID:(WoS)000497815800015 (Scopus)85073927406
Első szerző:Váradi Tímea (okleveles vegyész)
Cím:Homo- and Heteroassociations Drive Activation of ErbB3 / Váradi Tímea, Schneider Magdalena, Sevcsik Eva, Kiesenhofer Dominik, Baumgart Florian, Batta Gyula, Kovács Tamás, Platzer René, Huppa Johannes B., Szöllősi János, Schütz Gerhard J., Brameshuber Mario, Nagy Peter
Dátum:2019
ISSN:0006-3495
Megjegyzések:Dimerization or the formation of higher-order oligomers is required for the activation of ErbB receptor tyrosine kinases. The heregulin receptor, ErbB3, must heterodimerize with other members of the family, preferentially ErbB2, to form a functional signal transducing complex. Here, we applied single molecule imaging capable of detecting long-lived and mobile associations to measure their stoichiometry and mobility, and analyzed data from experiments globally taking the different lateral mobility of monomeric and dimeric molecular species into account. Although ErbB3 was largely monomeric in the absence of stimulation and ErbB2 coexpression, a small fraction was present as constitutive homodimers exhibiting a ?40% lower mobility than monomers. Heregulin-stimulation increased the homodimeric fraction of ErbB3 significantly and reduced the mobility of homodimers 4-fold compared to constitutive homodimers. Expression of ErbB2 elevated the homodimeric fraction of ErbB3 even in unstimulated cells and induced a ~2-fold reduction in the lateral mobility of ErbB3 homodimers. The mobility of ErbB2 was significantly lower than that of ErbB3, and heregulin induced a less pronounced decrease in the diffusion coefficient of all ErbB2 molecules as well as its heterodimers with ErbB3. The slower diffusion of ErbB2 compared to ErbB3 was abolished by depolymerizing actin filaments, while ErbB2-expression induced a substantial rearrangement of microfilaments implying a bidirectional interaction between ErbB2 and actin. Heregulin stimulation of cells coexpressing ErbB3 and ErbB2 led to the formation of ErbB3 homodimers and ErbB3/ErbB2 heterodimers in a competitive fashion. While pertuzumab, an antibody binding to the dimerization arm of ErbB2, completely abolished the formation of constitutive and heregulin-induced ErbB3/ErbB2 heterodimers, it only slightly blocked ErbB3 homodimerization. The results imply that a dynamic equilibrium exists between constitutive and ligand-induced homo- and heterodimers capable of shaping transmembrane signaling.
Tárgyszavak:Természettudományok Biológiai tudományok idegen nyelvű folyóiratközlemény külföldi lapban
folyóiratcikk
Megjelenés:Biophysical Journal. - 117 : 10 (2019), p. 1935-1947. -
További szerzők:Schneider, Magdalena Sevcsik Éva Kiesenhofer, Dominik Baumgart, Florian Batta Gyula (1979-) (biológus) Kovács Tamás (1985-) (általános orvos) Platzer, René Huppa, Johannes B. Szöllősi János (1953-) (biofizikus) Schütz, Gerhard Brameshuber, Mario Nagy Péter (1971-) (biofizikus)
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