Ca2+ permeation in cyclic nucleotide‐gated channels
Cyclic nucleotide‐gated (CNG) channels conduct Na+, K+ and Ca2+ currents under the control of cGMP and cAMP. Activation of CNG channels leads to depolarization of the membrane voltage and to a concomitant increase of the cytosolic Ca2+ concentration. Several polypeptides were identified that constit...
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| Main Authors: | , |
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| Format: | Article (Journal) |
| Language: | English |
| Published: |
4 Januar 1999
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| In: |
The EMBO journal
Year: 1999, Volume: 18, Issue: 1, Pages: 131-144 |
| ISSN: | 1460-2075 |
| DOI: | 10.1093/emboj/18.1.131 |
| Online Access: | Verlag, kostenfrei, Volltext: http://dx.doi.org/10.1093/emboj/18.1.131 Verlag, kostenfrei, Volltext: http://embojnl.embopress.org/content/18/1/131 
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| Author Notes: | Claudia Dzeja, Volker Hagen, U. Benjamin Kaupp and Stephan Frings |
| Summary: | Cyclic nucleotide‐gated (CNG) channels conduct Na+, K+ and Ca2+ currents under the control of cGMP and cAMP. Activation of CNG channels leads to depolarization of the membrane voltage and to a concomitant increase of the cytosolic Ca2+ concentration. Several polypeptides were identified that constitute principal and modulatory subunits of CNG channels in both neurons and non‐excitable cells, co‐assembling to form a variety of heteromeric proteins with distinct biophysical properties. Since the contribution of each channel type to Ca2+ signaling depends on its specific Ca2+ conductance, it is necessary to analyze Ca2+ permeation for each individual channel type. We have analyzed Ca2+ permeation in all principal subunits of vertebrates and for a principal subunit from Drosophila melanogaster . We measured the fractional Ca2+ current over the physiological range of Ca2+ concentrations and found that Ca2+ permeation is determined by subunit composition and modulated by membrane voltage and extracellular pH. Ca2+ permeation is controlled by the Ca2+‐binding affinity of the intrapore cation‐binding site, which varies profoundly between members of the CNG channel family, and gives rise to a surprising diversity in the ability to generate Ca2+ signals. |
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| Item Description: | Gesehen am 26.01.2017 Im Titel ist „2+“ hochgestellt |
| Physical Description: | Online Resource |
| ISSN: | 1460-2075 |
| DOI: | 10.1093/emboj/18.1.131 |