Potassium/sodium hyperpolarization-activated cyclic nucleotide-gated channel 4 is a
protein
Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residues. Proteins perform a vast array of functions within organisms, including catalysing metabolic reactions, DNA replication, res ...
that in humans is encoded by the ''HCN4''
gene
In biology, the word gene (from , ; "... Wilhelm Johannsen coined the word gene to describe the Mendelian units of heredity..." meaning ''generation'' or ''birth'' or ''gender'') can have several different meanings. The Mendelian gene is a b ...
.
There are four
HCN channel
Hyperpolarization-activated cyclic nucleotide–gated (HCN) channels are integral membrane proteins that serve as nonselective voltage-gated cation channels in the plasma membranes of heart and brain cells. HCN channels are sometimes referred to ...
s. HCN4 is prominently expressed in the
pace maker region of the mammalian
heart
The heart is a muscular organ in most animals. This organ pumps blood through the blood vessels of the circulatory system. The pumped blood carries oxygen and nutrients to the body, while carrying metabolic waste such as carbon dioxide to t ...
. Some humans with
bradycardia and
Sick sinus syndrome
Sinus node dysfunction (SND), also known as sick sinus syndrome (SSS), is a group of abnormal heart rhythms ( arrhythmias) usually caused by a malfunction of the sinus node, the heart's primary pacemaker. Tachycardia-bradycardia syndrome is a varia ...
have been shown to have mutations in their HCN4 gene.
The role of HCN channels in
autonomic control of heart rate is currently a matter of ongoing investigation.
Interactions
HCN4 has been shown to
interact
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with
HCN2.
See also
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Cyclic nucleotide-gated ion channel
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Anthropology and social sciences
* Cyclic history, a theory of history
* Cyclical theory, a theory of American political history associated with Arthur Schlesinger, Sr.
* Social cycle, various cycles in so ...
*
Funny current
The pacemaker current (or I''f'', or IK''f'', also referred to as the funny current) is an electric current in the heart that flows through the HCN channel or pacemaker channel. Such channels are important parts of the electrical conduction system ...
References
Further reading
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External links
GeneReviews/NIH/NCBI/UW entry on Brugada syndrome*
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Ion channels
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