Recombinant Human Voltage Dependent Anion Selective Channel Isoform 3 (hVDAC3) Forms Pores with a Very Small Conductance
Background/Aims: Voltage-dependent anion channels (VDAC), also known as eukaryotic porins, are located in the outer mitochondrial membrane and allow the flux of ions and small metabolites. While the pore-forming ability of recombinant VDAC1 and VDAC2 has been extensively studied during the last deca...
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| Format: | Article |
| Language: | English |
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Cell Physiol Biochem Press GmbH & Co KG
2014-08-01
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| Series: | Cellular Physiology and Biochemistry |
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| Online Access: | http://www.karger.com/Article/FullText/363047 |
| _version_ | 1818362708230144000 |
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| author | Vanessa Checchetto Simona Reina Andrea Magrì Ildikò Szabo Vito De Pinto |
| author_facet | Vanessa Checchetto Simona Reina Andrea Magrì Ildikò Szabo Vito De Pinto |
| author_sort | Vanessa Checchetto |
| collection | DOAJ |
| description | Background/Aims: Voltage-dependent anion channels (VDAC), also known as eukaryotic porins, are located in the outer mitochondrial membrane and allow the flux of ions and small metabolites. While the pore-forming ability of recombinant VDAC1 and VDAC2 has been extensively studied during the last decades, a clear-cut ion conducting channel activity has not been assigned to the VDAC3 isoform. Methods: Electrophysiological characterization of the recombinant protein purified and refolded was obtained after incorporation into planar lipid bilayers. Results: Here we report for the first time that recombinant hVDAC3, upon expression in E.coli and purification-refolding, shows a channel activity with a very small conductance (90 pS in 1 M KCl) with respect to the conductance of hVDAC1 (>3500 pS in 1 M KCl). Purified hVDAC3 allowed the passage of both chloride and gluconate anions and did not distinguish between potassium, sodium and calcium used as cations. In contrast to VDAC1, the channel was active also at transmembrane voltages higher than +/-40 mV and displayed a relatively high open probability even at +/-80 mV. hVDAC3 was only slightly voltage-dependent, displaying a tendency to adopt lower-conductance states at positive voltages applied to the cis chamber. In accordance with the small conductance of the pore, expression of hVDAC3 in a porin-less yeast strain allowed only partial recovery of the growth under non-permissive conditions. Conclusion: The observed electrophysiological properties of hVDAC3 are surprisingly different from the other isoforms and are discussed in relation to the proposed physiological role of the protein in mammalian cells. |
| first_indexed | 2024-12-13T21:36:52Z |
| format | Article |
| id | doaj.art-e40d72909f1c423fbe95699b3a8dcd59 |
| institution | Directory Open Access Journal |
| issn | 1015-8987 1421-9778 |
| language | English |
| last_indexed | 2024-12-13T21:36:52Z |
| publishDate | 2014-08-01 |
| publisher | Cell Physiol Biochem Press GmbH & Co KG |
| record_format | Article |
| series | Cellular Physiology and Biochemistry |
| spelling | doaj.art-e40d72909f1c423fbe95699b3a8dcd592022-12-21T23:30:39ZengCell Physiol Biochem Press GmbH & Co KGCellular Physiology and Biochemistry1015-89871421-97782014-08-0134384285310.1159/000363047363047Recombinant Human Voltage Dependent Anion Selective Channel Isoform 3 (hVDAC3) Forms Pores with a Very Small ConductanceVanessa ChecchettoSimona ReinaAndrea MagrìIldikò SzaboVito De PintoBackground/Aims: Voltage-dependent anion channels (VDAC), also known as eukaryotic porins, are located in the outer mitochondrial membrane and allow the flux of ions and small metabolites. While the pore-forming ability of recombinant VDAC1 and VDAC2 has been extensively studied during the last decades, a clear-cut ion conducting channel activity has not been assigned to the VDAC3 isoform. Methods: Electrophysiological characterization of the recombinant protein purified and refolded was obtained after incorporation into planar lipid bilayers. Results: Here we report for the first time that recombinant hVDAC3, upon expression in E.coli and purification-refolding, shows a channel activity with a very small conductance (90 pS in 1 M KCl) with respect to the conductance of hVDAC1 (>3500 pS in 1 M KCl). Purified hVDAC3 allowed the passage of both chloride and gluconate anions and did not distinguish between potassium, sodium and calcium used as cations. In contrast to VDAC1, the channel was active also at transmembrane voltages higher than +/-40 mV and displayed a relatively high open probability even at +/-80 mV. hVDAC3 was only slightly voltage-dependent, displaying a tendency to adopt lower-conductance states at positive voltages applied to the cis chamber. In accordance with the small conductance of the pore, expression of hVDAC3 in a porin-less yeast strain allowed only partial recovery of the growth under non-permissive conditions. Conclusion: The observed electrophysiological properties of hVDAC3 are surprisingly different from the other isoforms and are discussed in relation to the proposed physiological role of the protein in mammalian cells.http://www.karger.com/Article/FullText/363047Voltage Dependent Anion selective Channel isoform 3Pore-formationMitochondrial outer membranePlanar lipid bilayer |
| spellingShingle | Vanessa Checchetto Simona Reina Andrea Magrì Ildikò Szabo Vito De Pinto Recombinant Human Voltage Dependent Anion Selective Channel Isoform 3 (hVDAC3) Forms Pores with a Very Small Conductance Cellular Physiology and Biochemistry Voltage Dependent Anion selective Channel isoform 3 Pore-formation Mitochondrial outer membrane Planar lipid bilayer |
| title | Recombinant Human Voltage Dependent Anion Selective Channel Isoform 3 (hVDAC3) Forms Pores with a Very Small Conductance |
| title_full | Recombinant Human Voltage Dependent Anion Selective Channel Isoform 3 (hVDAC3) Forms Pores with a Very Small Conductance |
| title_fullStr | Recombinant Human Voltage Dependent Anion Selective Channel Isoform 3 (hVDAC3) Forms Pores with a Very Small Conductance |
| title_full_unstemmed | Recombinant Human Voltage Dependent Anion Selective Channel Isoform 3 (hVDAC3) Forms Pores with a Very Small Conductance |
| title_short | Recombinant Human Voltage Dependent Anion Selective Channel Isoform 3 (hVDAC3) Forms Pores with a Very Small Conductance |
| title_sort | recombinant human voltage dependent anion selective channel isoform 3 hvdac3 forms pores with a very small conductance |
| topic | Voltage Dependent Anion selective Channel isoform 3 Pore-formation Mitochondrial outer membrane Planar lipid bilayer |
| url | http://www.karger.com/Article/FullText/363047 |
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