ISSN:
0066-4278
Source:
Annual Reviews Electronic Back Volume Collection 1932-2001ff
Topics:
Medicine
,
Biology
Notes:
Cyclic nucleotideĐ??activated ion channels play a fundamental role in a variety of physiological processes. By opening in response to intracellular cyclic nucleotides, they translate changes in concentrations of signaling molecules to changes in membrane potential. These channels belong to two families: the cyclic nucleotideĐ??gated (CNG) channels and the hyperpolarization-activated cyclic nucleotideĐ??modulated (HCN) channels. The two families exhibit high sequence similarity and belong to the superfamily of voltage-gated potassium channels. Whereas HCN channels are activated by voltage and CNG channels are virtually voltage independent, both channels are activated by cyclic nucleotide binding. Furthermore, the channels are thought to have similar channel structures, leading to similar mechanisms of activation by cyclic nucleotides. However, although these channels are structurally and behaviorally similar, they have evolved to perform distinct physiological functions. This review describes the physiological roles and biophysical behavior of CNG and HCN channels. We focus on how similarities in structure and activation mechanisms result in common biophysical models, allowing CNG and HCN channels to be viewed as a single genre.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1146/annurev.physiol.68.040104.134728
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