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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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001-es BibID:	BIBFORM004669
Első szerző:	Nagy Péter (biofizikus)
Cím:	Apoptosis of murine thymocytes induced by extracellular ATP is dose- and cytosolic pH-dependent / Nagy, P. V., Feher, T., Morga, S., Matko, J.
Dátum:	2000
Megjegyzések:	Thymocytes from young Balb/C mice responded to low extracellular ATP (ATPec) doses (0.3 mM) with a rapid intracellular acidification (mean pH: ca. 0.3 pH unit) that was inhibited by the Ca2+ channel blocker verapamil, or by suramin (50 gammaM) and TNP-ATP (40 gammaM), potent P2x (and P2y) purinoreceptor antagonists. ATPec also triggered a remarkable DNA fragmentation and cell shrinkage detectable only at these low doses. DNA fragmentation gradually disappears with increasing [ATPec] above 0.5 mM, with a concomitant dominance of cytosolic alkalinization of the cells. Suramin and TNP-ATP also blocked the ATPec-triggered DNA fragmentation efficiently. oATP, inhibitor of P2z nonspecific ATP-gated membrane pores, and 2 mM extracellular Mg2+ did not influence either the cytosolic acidification or the DNA fragmentation, but almost completely abolished the intracellular alkalinization characteristic of P2z receptor activation at high ATPec doses. Antagonist-sensitivity of the ATPec-induced membrane potential responses indicates that hyperpolarization is associated with intracellular acidification, while rapid depolarization is linked to alkalinization. These data together indicate that the Ca2+-dependent hyperpolarization and cytosolic acidification triggered by low ATPec doses are essential early signals in apoptosis of murine thymocytes and are likely mediated by P2x1 type ATP-gated ion channels. Subset specificity of the early purinergic signals suggests that the double positive thymocytes are most sensitive to ATPec showing both P2z and P2x receptor activation characteristics, the double negative thymocytes preferentially show P2z-type, while single positive (CD4-CD8+ or CD4+CD8-) thymocytes respond mostly by weaker P2x-type changes, indicating that ATPec, similarly to adenosine may serve as a potential regulator of cell death and differentiation in the thymus.
Tárgyszavak:	Orvostudományok Elméleti orvostudományok idegen nyelvű folyóiratközlemény külföldi lapban Apoptosis
Megjelenés:	Immunology Letters. - 72 : 1 (2000), p. 23-30. -
További szerzők:	Fehér Tamás Morga, Sabina Matkó János (1952-) (biológus)
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001-es BibID:	BIBFORM005107
Első szerző:	Vámosi György (biofizikus)
Cím:	The role of supramolecular protein complexes and membrane potential in transmembrane signaling processes of lymphocytes / Vamosi, G., Bodnar, A., Damjanovich, S., Nagy, P., Varga, Z., Damjanovich, L.
Dátum:	2006
ISSN:	165-2478 (Print)
Megjegyzések:	The formation of protein patterns in lymphocyte plasma membranes is analyzed in the light of past and, also, very recent experiments. The analysis surveys the lateral organization of major histocompatibility complex glycoproteins, intercellular adhesion molecule-1, interleukin-2 and -15 receptors, Kv1.3 K+ ion channels and the T-cell receptor as well as their behavior under different conditions. These molecules form small- and large-scale clusters in the membrane of human lymphocytes. Many of the association motifs occur in other investigated cell types. The conclusions point toward a possible role for ion channel activities, membrane potential changes and alterations of the lateral organization of proteins in transmembrane signaling and cytotoxic interactions. In our outlook new factors that potentially affect membrane protein cluster formation and interactions are discussed. A role for MHC glycoproteins in concentrating membrane proteins and organizing protein patterns is suggested, and the possibility that the membrane potential may modulate protein conformation and, thereby, affect protein-protein interactions is pointed out. A well-defined role for the presence of ion channels in the immune synapse is offered, which could explain the significance of ion channel accumulation in the immune synapse together with the T-cell receptor.
Tárgyszavak:	Orvostudományok Elméleti orvostudományok idegen nyelvű folyóiratközlemény külföldi lapban analysis Animals Biophysics Cell Membrane Glycoproteins Human Humans Hungary immunology Intercellular Adhesion Molecule-1 Interleukin-2 Ion Channels Light Lymphocytes Major Histocompatibility Complex Membrane Potentials Membrane Proteins metabolism Multiprotein Complexes physiology Protein Conformation Proteins Research Signal Transduction Support T-Lymphocytes
Megjelenés:	Immunology Letters. - 104 : 1-2 (2006), p. 53-58. -
További szerzők:	Dóczy-Bodnár Andrea (1970-) (biofizikus) Damjanovich Sándor (1936-2017) (biofizikus) Nagy Péter (1971-) (biofizikus) Varga Zoltán (1969-) (biofizikus, szakfordító) Damjanovich László (1960-) (általános sebész)
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