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001-es BibID:	BIBFORM005182
Első szerző:	Gombos Imre
Cím:	Some new faces of membrane microdomains : a complex confocal fluorescence, differential polarization, and FCS imaging study on live immune cells / Gombos, I., Steinbach, G., Pomozi, I., Balogh, A., Vamosi, G., Gansen, A., Laszlo, G., Garab, G., Matko, J.
Dátum:	2008
ISSN:	552-4930 (Electronic)
Megjegyzések:	Lipid rafts are cholesterol- and glycosphingolipid-rich plasma membrane microdomains, which control signal transduction, cellular contacts, pathogen recognition, and internalization processes. Their stability/lifetime, heterogeneity remained still controversial, mostly due to the high diversity of raft markers and cellular models. The correspondence of the rafts of living cells to liquid ordered (Lo) domains of model membranes and the effect of modulating rafts on the structural dynamics of their bulk membrane environment are also yet unresolved questions. Spatial overlap of various lipid and protein raft markers on live cells was studied by confocal laser scanning microscopy, while fluorescence polarization of DiIC18(3) and Bodipy-phosphatidylcholine was imaged with differential polarization CLSM (DP-CLSM). Mobility of the diI probe under different conditions was assessed by fluorescence correlation spectroscopic (FCS). GM1 gangliosides highly colocalized with GPI-linked protein markers of rafts and a new anti-cholesterol antibody (AC8) in various immune cells. On the same cells, albeit not fully excluded from rafts, diI colocalized much less with raft markers of both lipid and protein nature, suggesting the Lo membrane regions are not equivalents to lipid rafts. The DP-CLSM technique was capable of imaging probe orientation and heterogeneity of polarization in the plasma membrane of live cells, reflecting differences in lipid order/packing. This property--in accordance with diI mobility assessed by FCS--was sensitive to modulation of rafts either through their lipids or proteins. Our complex imaging analysis demonstrated that two lipid probes--G(M1) and a new anti-cholesterol antibody--equivocally label the membrane rafts on a variety of cell types, while some raft-associated proteins (MHC-II, CD48, CD59, or CD90) do not colocalize with each other. This indicates the compositional heterogeneity of rafts. Usefulness of the DP-CLSM technique in imaging immune cell surface, in terms of lipid order/packing heterogeneities, was also shown together with its sensitivity to monitor biological modulation of lipid rafts.
Tárgyszavak:	Orvostudományok Elméleti orvostudományok idegen nyelvű folyóiratközlemény külföldi lapban analysis Animals Antibodies article Cell Line,Tumor Cells Cells,Cultured chemistry Cholesterol Comparative Study Confocal Fluorescence Fluorescence Polarization Humans Hungary immunology Lipids Membrane Microdomains methods Mice Mice, Inbred BALB C Mice, Inbred C3H Microscopy Microscopy, Confocal Microscopy, Fluorescence Microscopy, Polarization Proteins Rats Rats, Sprague-Dawley Research Research Support Signal Transduction Spectrometry, Fluorescence Support
Megjelenés:	Cytometry. Part A. - 73 : 3 (2008), p. 220-229. -
További szerzők:	Steinbach Gábor Pomozi István Balogh Andrea Vámosi György (1967-) (biofizikus) Gansen, Alexander László Glória Garab Győző Matkó János (1952-) (biológus)
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001-es BibID:	BIBFORM091923
Első szerző:	Kaňa, Radek
Cím:	Fast Diffusion of the Unassembled PetC1-GFP Protein in the Cyanobacterial Thylakoid Membrane / Radek Kaňa, Gábor Steinbach, Roman Sobotka, György Vámosi, Josef Komenda
Dátum:	2020
ISSN:	2075-1729
Megjegyzések:	Biological membranes were originally described as a fluid mosaic with uniform distribution of proteins and lipids. Later, heterogeneous membrane areas were found in many membrane systems including cyanobacterial thylakoids. In fact, cyanobacterial pigment?protein complexes (photosystems, phycobilisomes) form a heterogeneous mosaic of thylakoid membrane microdomains (MDs) restricting protein mobility. The trafficking of membrane proteins is one of the key factors for long-term survival under stress conditions, for instance during exposure to photoinhibitory light conditions. However, the mobility of unbound ♭free' proteins in thylakoid membrane is poorly characterized. In this work, we assessed the maximal diffusional ability of a small, unbound thylakoid membrane protein by semi-single molecule FCS (fluorescence correlation spectroscopy) method in the cyanobacterium Synechocystis sp. PCC6803. We utilized a GFP-tagged variant of the cytochrome b6f subunit PetC1 (PetC1-GFP), which was not assembled in the b6f complex due to the presence of the tag. Subsequent FCS measurements have identified a very fast diffusion of the PetC1-GFP protein in the thylakoid membrane (D = 0.14 ?? 2.95 m2s??1). This means that the mobility of PetC1-GFP was comparable with that of free lipids and was 50?500 times higher in comparison to the mobility of proteins (e.g., IsiA, LHCII?light-harvesting complexes of PSII) naturally associated with larger thylakoid membrane complexes like photosystems. Our results thus demonstrate the ability of free thylakoid-membrane proteins to move very fast, revealing the crucial role of protein?protein interactions in the mobility restrictions for large thylakoid protein complexes.
Tárgyszavak:	Természettudományok Biológiai tudományok idegen nyelvű folyóiratközlemény külföldi lapban folyóiratcikk proteins mobility photosynthesis FCS thylakoids cyanobacteria
Megjelenés:	Life. - 11 : 1 (2020), p. 1-12. -
További szerzők:	Steinbach Gábor Sobotka, Roman Vámosi György (1967-) (biofizikus) Komenda, Josef
Pályázati támogatás:	GINOP-2.3.2- 15-2016-00001 GINOP NKFIH NN 129371 Egyéb NKFIH ANN 135107 Egyéb
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