We found a match
Your institution may have access to this item. Find your institution then sign in to continue.
- Title
Ca<sup>2+</sup> permeation in cyclic nucleotide-gated channels.
- Authors
Dzeja, Claudia; Hagen, Volker; Kaupp, U. Benjamin; Frings, Stephan
- Abstract
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.
- Publication
EMBO Journal, 1999, Vol 18, Issue 1, p131
- ISSN
0261-4189
- Publication type
Academic Journal
- DOI
10.1093/emboj/18.1.131