CCL

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1.

001-es BibID:BIBFORM004933
Első szerző:Panyi György (biofizikus)
Cím:C-type inactivation of a voltage-gated K+ channel occurs by a cooperative mechanism / Panyi, G., Sheng, Z., Tu, L., Deutsch, C.
Dátum:1995
Megjegyzések:The lymphocyte voltage-gated K+ channel, Kv1.3, inactivates by a C-type process. We have elucidated the molecular basis for this process using a kinetic analysis of wild-type and mutant (A413V) Kv1.3 homo- and heteromultimeric currents in a mammalian lymphoid expression system. The medians of the measured inactivation time constants for wild-type and A413V homotetrameric currents are 204 and 4 ms, respectively. Co-expression of these subunits produces heteromultimeric channels manifesting inactivation kinetics intermediate between those of wild-type and A413V homomultimers. We have considered several models in which each subunit acts either independently or cooperatively to produce the observed inactivation kinetics. The cooperative model gives excellent fits to the data for any heteromultimeric composition of subunits, clearly distinguishing it from the independent models. In the cooperative model, the difference in free energy between the open and inactivated states of the channel is invariant with subunit composition and equals approximately 1.5 kcal/mol. Each subunit contributes equally to the activation free energy for transitions between open and inactivated states, with an A413V subunit decreasing the free energy barrier for inactivation (and for recovery from inactivation) by approximately 0.6 kcal/mol. Our results are consistent with a physical model in which the outer mouth of the channel constricts during C-type inactivation.
Tárgyszavak:Orvostudományok Elméleti orvostudományok idegen nyelvű folyóiratközlemény külföldi lapban
Animal
biosynthesis
Cells,Cultured
Electrophysiology
Human
Kinetics
Macromolecular Systems
Mathematics
Membrane Potentials
metabolism
methods
Mice
Models,Theoretical
Mutagenesis,Site-Directed
physiology
Plasmids
Point Mutation
Potassium
Potassium Channels
Recombinant Proteins
Transfection
Megjelenés:Biophysical Journal. - 69 : 3 (1995), p. 896-903. -
További szerzők:Sheng, Zufang Tu, LiWei Deutsch, Carol
Internet cím:elektronikus változat
elektronikus változat
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2.

001-es BibID:BIBFORM006071
Első szerző:Panyi György (biofizikus)
Cím:Assembly and suppression of endogenous Kv1.3 channels in human T cells / Panyi, G., Deutsch, C.
Dátum:1996
Megjegyzések:The predominant K+ channel in human T lymphocytes is Kv1.3, which inactivates by a C-type mechanism. To study assembly of these tetrameric channels in Jurkat, a human T-lymphocyte cell line, we have characterized the formation of heterotetrameric channels between endogenous wild-type (WT) Kv1.3 subunits and heterologously expressed mutant (A413V) Kv1.3 subunits. We use a kinetic analysis of C-type inactivation of currents produced by homotetrameric channels and heterotetrameric channels to determine the distribution of channels with different subunit stoichiometries. The distributions are well-described by either a binomial distribution or a binomial distribution plus a fraction of WT homotetramers, indicating that subunit assembly is a random process and that tetramers expressed in the plasma membrane do not dissociate and reassemble. Additionally, endogenous Kv1.3 current is suppressed by a heterologously expressed truncated Kv1.3 that contains the amino terminus and the first two transmembrane segments. The time course for suppression, which is maximal at 48 h after transfection, overlaps with the time interval for heterotetramer formation between heterologously expressed A413V and endogenous WT channels. Our findings suggest that diversity of K+ channel subtypes in a cell is regulated not by spatial segregation of monomeric pools, but rather by the degree of temporal overlap and the kinetics of subunit expression.
Tárgyszavak:Orvostudományok Elméleti orvostudományok idegen nyelvű folyóiratközlemény külföldi lapban
biosynthesis
Cell Line
drug effects
Electrophysiology
genetics
Human
Kinetics
Lymphocytes
metabolism
Patch-Clamp Techniques
physiology
Plasmids
Potassium
Potassium Channels
Recombinant Proteins
Support,U.S.Gov't,P.H.S.
T-Lymphocytes
Transfection
Megjelenés:The Journal of General Physiology. - 107 : 3 (1996), p. 409-420. -
További szerzők:Deutsch, Carol
Internet cím:elektronikus változat
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3.

001-es BibID:bibEBI00019290
Első szerző:Panyi György (biofizikus)
Cím:Cross talk between activation and slow inactivation gates of Shaker potassium channels / Panyi G., Deutsch C.
Dátum:2006
Megjegyzések:This study addresses the energetic coupling between the activation and slow inactivation gates of Shaker potassium channels. To track the status of the activation gate in inactivated channels that are nonconducting, we used two functional assays: the accessibility of a cysteine residue engineered into the protein lining the pore cavity (V474C) and the liberation by depolarization of a Cs(+) ion trapped behind the closed activation gate. We determined that the rate of activation gate movement depends on the state of the inactivation gate. A closed inactivation gate favors faster opening and slower closing of the activation gate. We also show that hyperpolarization closes the activation gate long before a channel recovers from inactivation. Because activation and slow inactivation are ubiquitous gating processes in potassium channels, the cross talk between them is likely to be a fundamental factor in controlling ion flux across membranes.
Tárgyszavak:Természettudományok Biológiai tudományok idegen nyelvű folyóiratközlemény külföldi lapban
Megjelenés:The Journal of General Physiology. - 128 : 5 (2006), p. 547-559. -
További szerzők:Deutsch, Carol
Internet cím:elektronikus változat
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4.

001-es BibID:BIBFORM002763
Első szerző:Panyi György (biofizikus)
Cím:Probing the cavity of the slow inactivated conformation of shaker potassium channels / Panyi G., Deutsch C.
Dátum:2007
Megjegyzések:Slow inactivation involves a local rearrangement of the outer mouth of voltage-gated potassium channels, but nothing is known regarding rearrangements in the cavity between the activation gate and the selectivity filter. We now report that the cavity undergoes a conformational change in the slow-inactivated state. This change is manifest as altered accessibility of residues facing the aqueous cavity and as a marked decrease in the affinity of tetraethylammonium for its internal binding site. These findings have implications for global alterations of the channel during slow inactivation and putative coupling between activation and slow-inactivation gates
Tárgyszavak:Természettudományok Biológiai tudományok idegen nyelvű folyóiratközlemény külföldi lapban
binding Sites
biophysics
cadmium
cell Line
chemistry
genetics
humans
Hungary
ion channel gating
kinetics
membrane Potentials
metabolism
Models, Biological
Models, Molecular
Mutagenesis, Site-Directed
Patch-Clamp Techniques
Potassium
Potassium Channel Blockers
Potassium Channels
Protein Conformation
Research
Shaker Superfamily of Potassium Channels
Support
Tetraethylammonium
Transfection
Megjelenés:The Journal of General Physiology. - 129 : 5 (2007), p. 403-418. -
További szerzők:Deutsch, Carol
Internet cím:DOI
elektronikus változat
Borító:

5.

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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6.

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
DOI
Intézményi repozitóriumban (DEA) tárolt változat
Borító:
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