A Newly Cloned ClC-3 Isoform, ClC-3d, as well as ClC-3a Mediates Cd2+-Sensitive Outwardly Rectifying Anion Currents
Background: ClC-3, a member of the ClC family, is predicted to have six isoforms, ClC-3a to -3f, with distinct N- and C-terminal amino acid sequences. There have been conflicting reports on the properties of ClC-3a (also known as the N-terminal short form of ClC-3) and ClC-3b (the N-terminal long fo...
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| Format: | Article |
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Cell Physiol Biochem Press GmbH & Co KG
2014-02-01
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| Series: | Cellular Physiology and Biochemistry |
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| Online Access: | http://www.karger.com/Article/FullText/358633 |
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| author | Toshiaki Okada Tenpei Akita Kaori Sato-Numata Md. Rafqul Islam Yasunobu Okada |
| author_facet | Toshiaki Okada Tenpei Akita Kaori Sato-Numata Md. Rafqul Islam Yasunobu Okada |
| author_sort | Toshiaki Okada |
| collection | DOAJ |
| description | Background: ClC-3, a member of the ClC family, is predicted to have six isoforms, ClC-3a to -3f, with distinct N- and C-terminal amino acid sequences. There have been conflicting reports on the properties of ClC-3a (also known as the N-terminal short form of ClC-3) and ClC-3b (the N-terminal long form of ClC-3) as plasmalemmal Cl- channels. Meanwhile, little is known about other isoforms. The amino acid sequence of ClC-3d (a C-terminal variant of the short form) listed in the NCBI database was derived from the genomic sequence, but there has been no experimental evidence for the mRNA. Methods: PCR-cloning was made to obtain the full coding region of ClC-3d from mouse liver. Its molecular expression on the plasma membrane was microscopically examined in HEK293T cells transfected with GFP-tagged ClC-3d. Its functional plasmalemmal expression and the properties of currents were studies by whole-cell recordings in the cells transfected with ClC-3d. Results: The cloned ClC-3d was found to be the only isoform which has an N-terminal amino acid sequence identical to ClC-3a. When introduced into HEK293T cells, a minor fraction of exogenous ClC-3d proteins was detected at the plasma membrane, and activation of anion currents was observed at neutral pH under normotonic conditions. The properties of ClC-3d currents were found to be shared by ClC-3a-mediated currents. Also, both ClC-3d and -3a currents were found to be sensitive to Cd2+. ClC-3d overexpression never affected the endogenous activity of acid- or swelling-activated anion channels. Conclusion: We thus conclude that plasmalemmal ClC-3d, like ClC-3a, mediates Cd2+-sensitive outwardly rectifying anion currents and that ClC-3d is distinct from the molecular entities of acid- and volume-sensitive anion channels. |
| first_indexed | 2024-12-10T22:07:10Z |
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| id | doaj.art-d82e4b93822547df97dde0b4eddfc2f0 |
| institution | Directory Open Access Journal |
| issn | 1015-8987 1421-9778 |
| language | English |
| last_indexed | 2024-12-10T22:07:10Z |
| publishDate | 2014-02-01 |
| publisher | Cell Physiol Biochem Press GmbH & Co KG |
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| series | Cellular Physiology and Biochemistry |
| spelling | doaj.art-d82e4b93822547df97dde0b4eddfc2f02022-12-22T01:31:43ZengCell Physiol Biochem Press GmbH & Co KGCellular Physiology and Biochemistry1015-89871421-97782014-02-0133353955610.1159/000358633358633A Newly Cloned ClC-3 Isoform, ClC-3d, as well as ClC-3a Mediates Cd2+-Sensitive Outwardly Rectifying Anion CurrentsToshiaki OkadaTenpei AkitaKaori Sato-NumataMd. Rafqul IslamYasunobu OkadaBackground: ClC-3, a member of the ClC family, is predicted to have six isoforms, ClC-3a to -3f, with distinct N- and C-terminal amino acid sequences. There have been conflicting reports on the properties of ClC-3a (also known as the N-terminal short form of ClC-3) and ClC-3b (the N-terminal long form of ClC-3) as plasmalemmal Cl- channels. Meanwhile, little is known about other isoforms. The amino acid sequence of ClC-3d (a C-terminal variant of the short form) listed in the NCBI database was derived from the genomic sequence, but there has been no experimental evidence for the mRNA. Methods: PCR-cloning was made to obtain the full coding region of ClC-3d from mouse liver. Its molecular expression on the plasma membrane was microscopically examined in HEK293T cells transfected with GFP-tagged ClC-3d. Its functional plasmalemmal expression and the properties of currents were studies by whole-cell recordings in the cells transfected with ClC-3d. Results: The cloned ClC-3d was found to be the only isoform which has an N-terminal amino acid sequence identical to ClC-3a. When introduced into HEK293T cells, a minor fraction of exogenous ClC-3d proteins was detected at the plasma membrane, and activation of anion currents was observed at neutral pH under normotonic conditions. The properties of ClC-3d currents were found to be shared by ClC-3a-mediated currents. Also, both ClC-3d and -3a currents were found to be sensitive to Cd2+. ClC-3d overexpression never affected the endogenous activity of acid- or swelling-activated anion channels. Conclusion: We thus conclude that plasmalemmal ClC-3d, like ClC-3a, mediates Cd2+-sensitive outwardly rectifying anion currents and that ClC-3d is distinct from the molecular entities of acid- and volume-sensitive anion channels.http://www.karger.com/Article/FullText/358633ClC-3dClC-3aAnion currentCadmium |
| spellingShingle | Toshiaki Okada Tenpei Akita Kaori Sato-Numata Md. Rafqul Islam Yasunobu Okada A Newly Cloned ClC-3 Isoform, ClC-3d, as well as ClC-3a Mediates Cd2+-Sensitive Outwardly Rectifying Anion Currents Cellular Physiology and Biochemistry ClC-3d ClC-3a Anion current Cadmium |
| title | A Newly Cloned ClC-3 Isoform, ClC-3d, as well as ClC-3a Mediates Cd2+-Sensitive Outwardly Rectifying Anion Currents |
| title_full | A Newly Cloned ClC-3 Isoform, ClC-3d, as well as ClC-3a Mediates Cd2+-Sensitive Outwardly Rectifying Anion Currents |
| title_fullStr | A Newly Cloned ClC-3 Isoform, ClC-3d, as well as ClC-3a Mediates Cd2+-Sensitive Outwardly Rectifying Anion Currents |
| title_full_unstemmed | A Newly Cloned ClC-3 Isoform, ClC-3d, as well as ClC-3a Mediates Cd2+-Sensitive Outwardly Rectifying Anion Currents |
| title_short | A Newly Cloned ClC-3 Isoform, ClC-3d, as well as ClC-3a Mediates Cd2+-Sensitive Outwardly Rectifying Anion Currents |
| title_sort | newly cloned clc 3 isoform clc 3d as well as clc 3a mediates cd2 sensitive outwardly rectifying anion currents |
| topic | ClC-3d ClC-3a Anion current Cadmium |
| url | http://www.karger.com/Article/FullText/358633 |
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