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1.

001-es BibID:BIBFORM069847
Első szerző:Hsu, Eric J.
Cím:Regulation of Na+ channel inactivation by the DIII and DIV voltage-sensing domains / Hsu Eric J., Zhu Wandi, Schubert Angela R., Voelker Taylor, Varga Zoltan, Silva Jonathan R.
Dátum:2017
ISSN:0022-1295
Tárgyszavak:Orvostudományok Elméleti orvostudományok idegen nyelvű folyóiratközlemény külföldi lapban
Megjelenés:Journal Of General Physiology 149 : 3 (2017), p. 389-403. -
További szerzők:Zhu, Wandi Schubert, Angela R. Voelker, Taylor Varga Zoltán (1969-) (biofizikus, szakfordító) Silva, Jonathan R.
Pályázati támogatás:KTIA_NAP_13-2-2015-0009
Egyéb
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Intézményi repozitóriumban (DEA) tárolt változat
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2.

001-es BibID:BIBFORM112395
035-os BibID:(scopus)85159838046 (cikkazonosító)e202313352
Első szerző:Szántó Gábor Tibor (vegyész)
Cím:Molecular rearrangements in S6 during slow inactivation in Shaker-IR potassium channels / Szanto Tibor G., Papp Ferenc, Zakany Florina, Varga Zoltan, Deutsch Carol, Panyi Gyorgy
Dátum:2023
ISSN:0022-1295 1540-7748
Megjegyzések:Voltage-gated K+ channels have distinct gates that regulate ion flux: the activation gate (A-gate) formed by the bundle crossing of the S6 transmembrane helices and the slow inactivation gate in the selectivity filter. These two gates are bidirectionally coupled. If coupling involves the rearrangement of the S6 transmembrane segment, then we predict state-dependent changes in the accessibility of S6 residues from the water-filled cavity of the channel with gating. To test this, we engineered cysteines, one at a time, at S6 positions A471, L472, and P473 in a T449A Shaker-IR background and determined the accessibility of these cysteines to cysteine-modifying reagents MTSET and MTSEA applied to the cytosolic surface of inside-out patches. We found that neither reagent modified either of the cysteines in the closed or the open state of the channels. On the contrary, A471C and P473C, but not L472C, were modified by MTSEA, but not by MTSET, if applied to inactivated channels with open A-gate (OI state). Our results, combined with earlier studies reporting reduced accessibility of residues I470C and V474C in the inactivated state, strongly suggest that the coupling between the A-gate and the slow inactivation gate is mediated by rearrangements in the S6 segment. The S6 rearrangements are consistent with a rigid rod-like rotation of S6 around its longitudinal axis upon inactivation. S6 rotation and changes in its environment are concomitant events in slow inactivation of Shaker KV channels.
Tárgyszavak:Orvostudományok Elméleti orvostudományok idegen nyelvű folyóiratközlemény külföldi lapban
folyóiratcikk
potassium channels
Megjelenés:Journal Of General Physiology. - 155 : 7 (2023), p. 1-14. -
További szerzők:Papp Ferenc (1979-) (biofizikus) Zákány Florina (1989-) (általános orvos) Varga Zoltán (1969-) (biofizikus, szakfordító) Deutsch, Carol Panyi György (1966-) (biofizikus)
Pályázati támogatás:KTIA_NAP_13-2-2015-0009
MTA
KTIA_ NAP_13-2-2017-0013
MTA
K132906
OTKA
K143071
OTKA
EFOP-3.6.2-16-2017-00006
EFOP
GINOP-2.3.2-15-2016-00044
GINOP
R01 GM052302
Egyéb
Internet cím:Szerző által megadott URL
DOI
Intézményi repozitóriumban (DEA) tárolt változat
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3.

001-es BibID:BIBFORM095633
035-os BibID:(cikkazonosító)e202012742
Első szerző:Szántó Gábor Tibor (vegyész)
Cím:Shaker-IR K+ channel gating in heavy water : role of structural water molecules in inactivation / Tibor G. Szanto, Szabolcs Gaal, Izhar Karbat, Zoltan Varga, Eitan Reuveny, Gyorgy Panyi
Dátum:2021
ISSN:0022-1295 1540-7748
Tárgyszavak:Orvostudományok Elméleti orvostudományok idegen nyelvű folyóiratközlemény külföldi lapban
folyóiratcikk
Megjelenés:Journal of General Physiology. - 153 : 6 (2021), p. 1-27. -
További szerzők:Gaál Szabolcs Karbat, Izhar Varga Zoltán (1969-) (biofizikus, szakfordító) Reuveny, Eitan Panyi György (1966-) (biofizikus)
Internet cím:Szerző által megadott URL
DOI
Intézményi repozitóriumban (DEA) tárolt változat
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4.

001-es BibID:BIBFORM085966
Első szerző:Szántó Gábor Tibor (vegyész)
Cím:The activation gate controls steady-state inactivation and recovery from inactivation in Shaker / Szanto Tibor G., Zakany Florina, Papp Ferenc, Varga Zoltan, Deutsch Carol J., Panyi Gyorgy
Dátum:2020
ISSN:0022-1295 1540-7748
Megjegyzések:Despite major advances in the structure determination of ion channels, the sequence of molecular rearrangements at negative membrane potentials in voltage-gated potassium channels of the Shaker family remains unknown. Four major composite gating states are documented during the gating process: closed (C), open (O), open-inactivated (OI), and closed-inactivated (CI). Although many steps in the gating cycle have been clarified experimentally, the development of steady-state inactivation at negative membrane potentials and mandatory gating transitions for recovery from inactivation have not been elucidated. In this study, we exploit the biophysical properties of Shaker-IR mutants T449A/V474C and T449A/V476C to evaluate the status of the activation and inactivation gates during steady-state inactivation and upon locking the channel open with intracellular Cd 2+ . We conclude that at negative membrane potentials, the gating scheme of Shaker channels can be refined in two aspects. First, the most likely pathway for the development of steady-state inactivation is C?O?OI#CI. Second, the OI?CI transition is a prerequisite for recovery from inactivation. These findings are in accordance with the widely accepted view that tight coupling is present between the activation and C-type inactivation gates in Shaker and underscore the role of steady-state inactivation and recovery from inactivation as determinants of excitability.
Tárgyszavak:Orvostudományok Elméleti orvostudományok idegen nyelvű folyóiratközlemény külföldi lapban
folyóiratcikk
Megjelenés:Journal Of General Physiology. - 152 : 8 (2020), p. 1-12. -
További szerzők:Zákány Florina (1989-) (általános orvos) Papp Ferenc (1979-) (biofizikus) Varga Zoltán (1969-) (biofizikus, szakfordító) Deutsch, Carol Panyi György (1966-) (biofizikus)
Pályázati támogatás:KTIA_NAP_13-2-2015-0009
MTA
KTIA_NAP_132-2017-0013
MTA
EFOP-3.6.2-16-2017-00006
EFOP
GINOP-2.3.2-15-2016-00015
GINOP
NKFIH K132906
OTKA
NKFIH K119417
OTKA
ÚNKP-19-3-III-DE-92
Egyéb
GM 52302
Egyéb
Internet cím:Szerző által megadott URL
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Intézményi repozitóriumban (DEA) tárolt változat
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5.

001-es BibID:BIBFORM004720
Első szerző:Varga Zoltán (biofizikus, szakfordító)
Cím:Cations affect the rate of gating charge recovery in wild-type and W434F Shaker channels through a variety of mechanisms / Varga, Z., Rayner, M. D., Starkus, J. G.
Dátum:2002
Megjegyzések:In this study we examine the effects of ionic conditions on the gating charge movement in the fast inactivation-removed wild-type Shaker channel and its W434F mutant. Our results show that various ionic conditions influence the rate at which gating charge returns during repolarization following a depolarizing pulse. These effects are realized through different mechanisms, which include the regulation of channel closing by occupying the cavity, the modulation of transitions into inactivated states, and effects on transitions between closed states via a direct interaction with the channel's gating charges. In generating these effects the cations act from the different binding sites within the pore. Ionic conditions, in which conducting wild-type channels close at different rates, do not significantly affect the rate of charge recovery upon repolarization. In these conditions, channel closing is fast enough not to be rate-limiting in the charge recovery process. In the permanently P-inactivated mutant channel, however, channel closing becomes the rate-limiting step, presumably due to weakened ion-ion interactions inside the pore and a slower intrinsic rate of gate closure. Thus, variations in closing rate induced by different ions are reflected as variations in the rate of charge recovery. In 115 mM internal Tris(+) and external K(+), Cs(+), or Rb(+), low inward permeation of these ions can be observed through the mutant channel. In these instances, channel closing becomes slower than in Tris(+)(O)//Tris(+)(I) solutions showing resemblance to the wild-type channel, where higher inward ionic fluxes also retard channel closing. Our data indicate that cations regulate the transition into the inactivated states from the external lock-in site and possibly the deep site. The direct action of barium on charge movement is probably exerted from the deep site, but this effect is not very significant for monovalent cations.
Tárgyszavak:Orvostudományok Elméleti orvostudományok idegen nyelvű folyóiratközlemény külföldi lapban
Binding Sites
Research
Megjelenés:The Journal of General Physiology. - 119 : 5 (2002), p. 467-485. -
További szerzők:Rayner, Martin D. Starkus, John G.
Internet cím:elektronikus változat
DOI
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6.

001-es BibID:BIBFORM073723
Első szerző:Zhu, Wandi
Cím:Mechanisms of noncovalent β subunit regulation of NaV channel gating / Wandi Zhu, Taylor L. Voelker, Zoltan Varga, Angela R. Schubert, Jeanne M. Nerbonne, Jonathan R. Silva
Dátum:2017
ISSN:0022-1295 1540-7748
Megjegyzések:Voltage-gated Na+ (Na) channels comprise a macromolecular complex whose components tailor channel function.Key components arethe non-covalently bound ?1and ?3subunits that regulatechannel gating, expression,andpharmacology.Here,we probethe molecular basis of this regulationby applying voltage clamp fluorometrytomeasurehow the ?subunits affectthe conformational dynamics of the cardiacNaVV channel (Na1.5) voltage-sensingdomains (VSDs). The pore-formingNa1.5 ? subunit contains four domains (DI?DIV), each with aVSD. Our results show that ?1 regulates NaVV1.5 by modulating the DIV-VSD, whereas ?3 alters channel kineticsmainly through DIII-VSD interaction. Introduction of a quenching tryptophan into the extracellular region of the?3 transmembrane segment inverted the DIII-VSD fluorescence. Additionally, a fluorophore tethered to ?3 at thesame position produced voltage-dependent fluorescence dynamics strongly resembling those of the DIII-VSD.Together, these results provide compelling evidence that ?3 binds proximally to the DIII-VSD. Molecular-level differences in ?1 and ?3 interaction with the ? subunit lead to distinct activation and inactivation recovery kinetics, significantly affecting Na channel regulation of cell excitability.
Tárgyszavak:Orvostudományok Elméleti orvostudományok idegen nyelvű folyóiratközlemény külföldi lapban
Voltage-gated Na
Megjelenés:Journal Of General Physiology. - 149 : 8 (2017), p. 813-831. -
További szerzők:Voelker, Taylor Varga Zoltán (1969-) (biofizikus, szakfordító) Schubert, Angela R. Nerbonne, Jeanne M. Silva, Jonathan R.
Pályázati támogatás:KTIA_ NAP_13-2-2015-0009
MTA
Bolyai fellowship
MTA
Internet cím:Szerző által megadott URL
DOI
Intézményi repozitóriumban (DEA) tárolt változat
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