TY - JOUR AU - Pethő, Zoltán Dénes AU - Pajtás, Dávid AU - Piga, Martina AU - Magyar, Zsuzsanna Édua AU - Zákány, Florina AU - Kovács, Tamás AU - Zidar, Nace AU - Panyi, György AU - Varga, Zoltán AU - Papp, Ferenc TI - A synthetic flavonoid derivate in the plasma membrane transforms the voltage‐clamp fluorometry signal of CiHv1 JF - FEBS JOURNAL J2 - FEBS J PY - 2024 PG - 18 SN - 1742-464X DO - 10.1111/febs.17105 UR - https://m2.mtmt.hu/api/publication/34722791 ID - 34722791 N1 - Early View AB - Voltage‐clamp fluorometry (VCF) enables the study of voltage‐sensitive proteins through fluorescent labeling accompanied by ionic current measurements for voltage‐gated ion channels. The heterogeneity of the fluorescent signal represents a significant challenge in VCF. The VCF signal depends on where the cysteine mutation is incorporated, making it difficult to compare data among different mutations and different studies and standardize their interpretation. We have recently shown that the VCF signal originates from quenching amino acids in the vicinity of the attached fluorophores, together with the effect of the lipid microenvironment. Based on these, we performed experiments to test the hypothesis that the VCF signal could be altered by amphiphilic quenching molecules in the cell membrane. Here we show that a phenylalanine‐conjugated flavonoid (4‐oxo‐2‐phenyl‐4H‐chromene‐7‐yl)‐phenylalanine, (later Oxophench) has potent effects on the VCF signals of the Ciona intestinalis H V 1 (CiHv1) proton channel. Using spectrofluorimetry, we showed that Oxophench quenches TAMRA (5(6)‐carboxytetramethylrhodamine‐(methane thiosulfonate)) fluorescence. Moreover, Oxophench reduces the baseline fluorescence in oocytes and incorporates into the cell membrane while reducing the membrane fluidity of HEK293 cells. Our model calculations confirmed that Oxophench, a potent membrane‐bound quencher, modifies the VCF signal during conformational changes. These results support our previously published model of VCF signal generation and point out that a change in the VCF signal may not necessarily indicate an altered conformational transition of the investigated protein. LA - English DB - MTMT ER - TY - JOUR AU - Szántó, Gábor Tibor AU - Papp, Ferenc AU - Zákány, Florina AU - Varga, Zoltán AU - Deutsch, Carol AU - Panyi, György TI - Molecular rearrangements in S6 during slow inactivation in Shaker -IR potassium channels JF - JOURNAL OF GENERAL PHYSIOLOGY J2 - J GEN PHYSIOL VL - 155 PY - 2023 IS - 7 PG - 14 SN - 0022-1295 DO - 10.1085/jgp.202313352 UR - https://m2.mtmt.hu/api/publication/34007263 ID - 34007263 AB - 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. LA - English DB - MTMT ER - TY - JOUR AU - Nemes, Balázs AU - László, Szabolcs AU - Zsidó, Balázs Zoltán AU - Hetényi, Csaba AU - Fehér, Ádám AU - Papp, Ferenc AU - Varga, Zoltán AU - Szőke, Éva AU - Sándor, Zoltán AU - Pintér, Erika TI - Elucidation of the binding mode of organic polysulfides on the human TRPA1 receptor JF - FRONTIERS IN PHYSIOLOGY J2 - FRONT PHYSIOL VL - 14 PY - 2023 PG - 16 SN - 1664-042X DO - 10.3389/fphys.2023.1180896 UR - https://m2.mtmt.hu/api/publication/34006433 ID - 34006433 N1 - * Megosztott szerzőség AB - Introduction: Previous studies have established that endogenous inorganic polysulfides have significant biological actions activating the Transient Receptor Potential Ankyrin 1 (TRPA1) receptor. Organic polysulfides exert similar effects, but they are much more stable molecules, therefore these compounds are more suitable as drugs. In this study, we aimed to better understand the mechanism of action of organic polysulfides by identification of their binding site on the TRPA1 receptor. LA - English DB - MTMT ER - TY - JOUR AU - Fehér, Ádám AU - Korpos, Éva AU - Piga, Martina AU - Tomasic, Tihomir AU - Zidar, Nace AU - Gyöngyösi, Adrienn AU - Kállai, Judit AU - Lányi, Árpád AU - Papp, Ferenc AU - Gyuris, Katinka AU - Varga, Zoltán TI - Identification of a new family of inhibitors of the human Hv1 proton channel JF - BIOPHYSICAL JOURNAL J2 - BIOPHYS J VL - 122 PY - 2023 IS - 3 SP - 256a EP - 257a SN - 0006-3495 DO - 10.1016/j.bpj.2022.11.1479 UR - https://m2.mtmt.hu/api/publication/33674323 ID - 33674323 LA - English DB - MTMT ER - TY - JOUR AU - Korpos, Éva AU - Papp, Ferenc TI - New ‘kids’ on the voltage‐gated proton channel block JF - FEBS JOURNAL J2 - FEBS J VL - 290 PY - 2023 IS - 4 SP - 970 EP - 973 PG - 4 SN - 1742-464X DO - 10.1111/febs.16670 UR - https://m2.mtmt.hu/api/publication/33215047 ID - 33215047 LA - English DB - MTMT ER - TY - JOUR AU - Papp, Ferenc AU - Toombes, Gilman E. S. AU - Pethő, Zoltán Dénes AU - Bagosi, Adrienn AU - Fehér, Ádám AU - Almássy, János AU - Borrego Terrazas, Jesus Angel AU - Kuki, Ákos AU - Kéki, Sándor AU - Panyi, György AU - Varga, Zoltán TI - Multiple mechanisms contribute to fluorometry signals from the voltage-gated proton channel JF - COMMUNICATIONS BIOLOGY J2 - COMMUN BIOL VL - 5 PY - 2022 IS - 1 SN - 2399-3642 DO - 10.1038/s42003-022-04065-6 UR - https://m2.mtmt.hu/api/publication/33209098 ID - 33209098 AB - Voltage-clamp fluorometry (VCF) supplies information about the conformational changes of voltage-gated proteins. Changes in the fluorescence intensity of the dye attached to a part of the protein that undergoes a conformational rearrangement upon the alteration of the membrane potential by electrodes constitute the signal. The VCF signal is generated by quenching and dequenching of the fluorescence as the dye traverses various local environments. Here we studied the VCF signal generation, using the Hv1 voltage-gated proton channel as a tool, which shares a similar voltage-sensor structure with voltage-gated ion channels but lacks an ion-conducting pore. Using mutagenesis and lipids added to the extracellular solution we found that the signal is generated by the combined effects of lipids during movement of the dye relative to the plane of the membrane and by quenching amino acids. Our 3-state model recapitulates the VCF signals of the various mutants and is compatible with the accepted model of two major voltage-sensor movements. LA - English DB - MTMT ER - TY - JOUR AU - Bátai, István Zoárd AU - Dombi, Ágnes AU - Borbély, Éva AU - Fehér, Ádám AU - Papp, Ferenc AU - Varga, Zoltán AU - Mócsai, Attila AU - Helyes, Zsuzsanna AU - Pintér, Erika AU - Pozsgai, Gábor TI - Investigation of the Role of the TRPA1 Ion Channel in Conveying the Effect of Dimethyl Trisulfide on Vascular and Histological Changes in Serum-Transfer Arthritis. JF - PHARMACEUTICALS J2 - PHARMACEUTICALS-BASE VL - 15 PY - 2022 IS - 6 PG - 15 SN - 1424-8247 DO - 10.3390/ph15060671 UR - https://m2.mtmt.hu/api/publication/32907493 ID - 32907493 N1 - Funding Agency and Grant Number: National Research, Development, and Innovation Office (NKFIH), Hungary [OTKA FK 132454, OTKA KKP 129954]; Ministry for Innovation and Technology in Hungary Funding text: This research was funded by the National Research, Development, and Innovation Office (NKFIH), Hungary, under grant numbers OTKA FK 132454 and OTKA KKP 129954. The research also was financed by the Thematic Excellence Program 2020 (Institutional Excellence Subprogram) and Thematic Excellence Program 2021 Health Subprogram of the Ministry for Innovation and Technology in Hungary, within the framework of the second thematic program of the University of Pecs, within the framework of the EGA-16 project of Pecs University. AB - Rheumatoid arthritis (RA) is one of the most prevalent autoimmune diseases. Its therapy is often challenging, even in the era of biologicals. Previously, we observed the anti-inflammatory effects of garlic-derived organic polysulfide dimethyl trisulfide (DMTS). Some of these effects were mediated by activation of the TRPA1 ion channel. TRPA1 was mostly expressed in a subset of nociceptor neurons. We decided to investigate the action of DMTS in K/BxN serum-transfer arthritis, which is a relevant model of RA. TRPA1 gene knockout (KO) and wild-type (WT) mice were used. The interaction of DMTS and TRPA1 was examined using a patch clamp in CHO cells. Arthritis was characterized by mechanical hyperalgesia, paw swelling, movement range of the ankle joint, hanging performance, plasma extravasation rate, myeloperoxidase activity, and histological changes in the tibiotarsal joint. DMTS activated TRPA1 channels dose-dependently. DMTS treatment reduced paw swelling and plasma extravasation in both TRPA1 WT and KO animals. DMTS-treated TRPA1 KO animals developed milder collagen deposition in the inflamed joints than WT ones. TRPA1 WT mice did not exhibit significant cartilage damage compared to ones administered a vehicle. We concluded that DMTS and related substances might evolve into novel complementary therapeutic aids for RA patients. LA - English DB - MTMT ER - TY - JOUR AU - Fehér, Ádám AU - Borrego Terrazas, Jesus Angel AU - Cardoso-Arenas, Samuel AU - Arenas, Iván AU - Clement, Herlinda AU - Corzo, Gerardo AU - Panyi, György AU - Varga, Zoltán AU - Papp, Ferenc TI - Discovery of human Hv1 channel peptide inhibitors JF - BIOPHYSICAL JOURNAL J2 - BIOPHYS J VL - 121 PY - 2022 IS - 3 SP - 504A EP - 504A PG - 1 SN - 0006-3495 DO - 10.1016/j.bpj.2021.11.259 UR - https://m2.mtmt.hu/api/publication/32812800 ID - 32812800 LA - English DB - MTMT ER - TY - JOUR AU - Papp, Ferenc AU - Toombes, Gilman E. AU - Pethő, Zoltán Dénes AU - Bagosi, Adrienn AU - Fehér, Ádám AU - Almássy, János AU - Kuki, Ákos AU - Kéki, Sándor AU - Panyi, György AU - Varga, Zoltán TI - Multiple mechanisms contribute to fluorometry signals from the voltage-gated proton channel JF - BIOPHYSICAL JOURNAL J2 - BIOPHYS J VL - 121 PY - 2022 IS - 3, Suppl. 1 SP - 247A EP - 247A PG - 1 SN - 0006-3495 DO - 10.1016/j.bpj.2021.11.1481 UR - https://m2.mtmt.hu/api/publication/32812792 ID - 32812792 LA - English DB - MTMT ER - TY - JOUR AU - Fehér, Ádám AU - Pócsi, Marianna AU - Papp, Ferenc AU - Szántó, Gábor Tibor AU - Csóti, Ágota AU - Fejes, Zsolt AU - Nagy, Béla AU - Nemes, Balázs AU - Varga, Zoltán TI - Functional Voltage-Gated Sodium Channels Are Present in the Human B Cell Membrane JF - CELLS J2 - CELLS-BASEL VL - 11 PY - 2022 IS - 7 PG - 15 SN - 2073-4409 DO - 10.3390/cells11071225 UR - https://m2.mtmt.hu/api/publication/32782231 ID - 32782231 N1 - Academic Editor: Rajesh Khanna AB - B cells express various ion channels, but the presence of voltage-gated sodium (NaV) channels has not been confirmed in the plasma membrane yet. In this study, we have identified several NaV channels, which are expressed in the human B cell membrane, by electrophysiological and molecular biology methods. The sensitivity of the detected sodium current to tetrodotoxin was between the values published for TTX-sensitive and TTX-insensitive channels, which suggests the co-existence of multiple NaV1 subtypes in the B cell membrane. This was confirmed by RT-qPCR results, which showed high expression of TTX-sensitive channels along with the lower expression of TTX-insensitive NaV1 channels. The biophysical characteristics of the currents also supported the expression of multiple NaV channels. In addition, we investigated the potential functional role of NaV channels by membrane potential measurements. Removal of Na+ from the extracellular solution caused a reversible hyperpolarization, supporting the role of NaV channels in shaping and maintaining the resting membrane potential. As this study was mainly limited to electrophysiological properties, we cannot exclude the possible non-canonical functions of these channels. This work concludes that the presence of voltage-gated sodium channels in the plasma membrane of human B cells should be recognized and accounted for in the future. LA - English DB - MTMT ER -