Click here to close
Hello! We notice that you are using Internet Explorer, which is not supported by Xenbase and may cause the site to display incorrectly.
We suggest using a current version of Chrome,
FireFox, or Safari.
Single-channel properties of ionic channels gated by cyclic nucleotides.
Bucossi G
,
Nizzari M
,
Torre V
.
???displayArticle.abstract???
This paper presents an extensive analysis of single-channel properties of cyclic nucleotide gated (CNG) channels, obtained by injecting into Xenopus laevis oocytes the mRNA encoding for the alpha and beta subunits from bovine rods. When the alpha and beta subunits of the CNG channel are coexpressed, at least three types of channels with different properties are observed. One type of channel has well-resolved, multiple conductive levels at negative voltages, but not at positive voltages. The other two types of channel are characterized by flickering openings, but are distinguished because they have a low and a high conductance. The alpha subunit of CNG channels has a well-defined conductance of about 28 pS, but multiple conductive levels are observed in mutant channels E363D and T364M. The conductance of these open states is modulated by protons and the membrane voltage, and has an activation energy around 44 kJ/mol. The relative probability of occupying any of these open states is independent of the cGMP concentration, but depends on extracellular protons. The open probability in the presence of saturating cGMP was 0.78, 0.47, 0.5, and 0.007 in the w.t. and mutants E363D, T364M, and E363G, and its dependence on temperature indicates that the thermodynamics of the transition between the closed and open state is also affected by mutations in the pore region. These results suggest that CNG channels have different conductive levels, leading to the existence of multiple open states in homomeric channels and to the flickering behavior in heteromeric channels, and that the pore is an essential part of the gating of CNG channels.
Baumann,
Primary structure and functional expression of a Drosophila cyclic nucleotide-gated channel present in eyes and antennae.
1994, Pubmed,
Xenbase
Baumann,
Primary structure and functional expression of a Drosophila cyclic nucleotide-gated channel present in eyes and antennae.
1994,
Pubmed
,
Xenbase
Bönigk,
Rod and cone photoreceptor cells express distinct genes for cGMP-gated channels.
1993,
Pubmed
,
Xenbase
Bradley,
Heteromeric olfactory cyclic nucleotide-gated channels: a subunit that confers increased sensitivity to cAMP.
1994,
Pubmed
Bucossi,
Time-dependent current decline in cyclic GMP-gated bovine channels caused by point mutations in the pore region expressed in Xenopus oocytes.
1996,
Pubmed
,
Xenbase
Chen,
A new subunit of the cyclic nucleotide-gated cation channel in retinal rods.
1993,
Pubmed
,
Xenbase
Dhallan,
Primary structure and functional expression of a cyclic nucleotide-activated channel from olfactory neurons.
1990,
Pubmed
Dhallan,
Human rod photoreceptor cGMP-gated channel: amino acid sequence, gene structure, and functional expression.
1992,
Pubmed
Eismann,
A single negative charge within the pore region of a cGMP-gated channel controls rectification, Ca2+ blockage, and ionic selectivity.
1994,
Pubmed
,
Xenbase
Frings,
Profoundly different calcium permeation and blockage determine the specific function of distinct cyclic nucleotide-gated channels.
1995,
Pubmed
,
Xenbase
Gordon,
Localization of regions affecting an allosteric transition in cyclic nucleotide-activated channels.
1995,
Pubmed
,
Xenbase
Goulding,
Molecular mechanism of cyclic-nucleotide-gated channel activation.
1994,
Pubmed
,
Xenbase
Goulding,
Molecular cloning and single-channel properties of the cyclic nucleotide-gated channel from catfish olfactory neurons.
1992,
Pubmed
Hamill,
Improved patch-clamp techniques for high-resolution current recording from cells and cell-free membrane patches.
1981,
Pubmed
Karpen,
Why do cyclic nucleotide-gated channels have the jitters?
1997,
Pubmed
Karpen,
Covalent activation of retinal rod cGMP-gated channels reveals a functional heterogeneity in the ligand binding sites.
1996,
Pubmed
,
Xenbase
Kaupp,
Primary structure and functional expression from complementary DNA of the rod photoreceptor cyclic GMP-gated channel.
1989,
Pubmed
,
Xenbase
Kaupp,
Family of cyclic nucleotide gated ion channels.
1995,
Pubmed
Körschen,
A 240 kDa protein represents the complete beta subunit of the cyclic nucleotide-gated channel from rod photoreceptor.
1995,
Pubmed
Liu,
Subunit stoichiometry of cyclic nucleotide-gated channels and effects of subunit order on channel function.
1996,
Pubmed
Ludwig,
Primary structure of cAMP-gated channel from bovine olfactory epithelium.
1990,
Pubmed
Matthews,
Activation of single ion channels from toad retinal rod inner segments by cyclic GMP: concentration dependence.
1988,
Pubmed
Nizzari,
Single-channel properties of cloned cGMP-activated channels from retinal rods.
1993,
Pubmed
,
Xenbase
Park,
Divalent cation selectivity in a cyclic nucleotide-gated ion channel.
1995,
Pubmed
,
Xenbase
Pittler,
Primary structure and chromosomal localization of human and mouse rod photoreceptor cGMP-gated cation channel.
1992,
Pubmed
Root,
Identification of an external divalent cation-binding site in the pore of a cGMP-activated channel.
1993,
Pubmed
,
Xenbase
Root,
Two identical noninteracting sites in an ion channel revealed by proton transfer.
1994,
Pubmed
,
Xenbase
Sesti,
The multi-ion nature of the cGMP-gated channel from vertebrate rods.
1995,
Pubmed
,
Xenbase
Sesti,
Gating, selectivity and blockage of single channels activated by cyclic GMP in retinal rods of the tiger salamander.
1994,
Pubmed
Sesti,
Effect of changing temperature on the ionic permeation through the cyclic GMP-gated channel from vertebrate photoreceptors.
1996,
Pubmed
,
Xenbase
Stern,
Control of the light-regulated current in rod photoreceptors by cyclic GMP, calcium, and l-cis-diltiazem.
1986,
Pubmed
Sun,
Exposure of residues in the cyclic nucleotide-gated channel pore: P region structure and function in gating.
1996,
Pubmed
Taylor,
Conductance and kinetics of single cGMP-activated channels in salamander rod outer segments.
1995,
Pubmed
Varnum,
Subunit interactions in the activation of cyclic nucleotide-gated ion channels.
1996,
Pubmed
Varnum,
Molecular mechanism for ligand discrimination of cyclic nucleotide-gated channels.
1995,
Pubmed
Weyand,
Cloning and functional expression of a cyclic-nucleotide-gated channel from mammalian sperm.
1994,
Pubmed
,
Xenbase
Yau,
Cyclic GMP-activated conductance of retinal photoreceptor cells.
1989,
Pubmed
