Potassium voltage-gated channel subfamily D member 3 also known as K
v4.3 is a
protein
Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residue (biochemistry), residues. Proteins perform a vast array of functions within organisms, including Enzyme catalysis, catalysing metab ...
that in humans is encoded by the ''KCND3''
gene
In biology, the word gene has two meanings. The Mendelian gene is a basic unit of heredity. The molecular gene is a sequence of nucleotides in DNA that is transcribed to produce a functional RNA. There are two types of molecular genes: protei ...
.
It contributes to the
cardiac transient outward potassium current (I
to1), the main contributing current to the
repolarizing phase 1 of the cardiac action potential.
Function
Voltage-gated potassium (
Kv) channels represent the most complex class of voltage-gated ion channels from both functional and structural standpoints. Their diverse functions include regulating neurotransmitter release, heart rate, insulin secretion, neuronal excitability, epithelial electrolyte transport, smooth muscle contraction, and cell volume. Four sequence-related potassium channel genes – shaker, shaw, shab, and shal – have been identified in Drosophila, and each has been shown to have human homolog(s).
K
v4.3 is a member of the potassium channel, voltage-gated, shal-related subfamily, members of which form voltage-activated A-type potassium ion channels and are prominent in the repolarization phase of the
action potential
An action potential (also known as a nerve impulse or "spike" when in a neuron) is a series of quick changes in voltage across a cell membrane. An action potential occurs when the membrane potential of a specific Cell (biology), cell rapidly ri ...
. This member includes two isoforms with different sizes, which are encoded by alternatively spliced transcript variants of this gene.
Clinical significance
Gain of function is believed to cause
Brugada syndrome although only indirectly shown by mutations in the beta subunit
KCNE3 which causes gain of function of K
v4.3.
See also
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Voltage-gated potassium channel
Voltage-gated potassium channels (VGKCs) are potassium channel, transmembrane channels specific for potassium and Voltage-gated ion channel, sensitive to voltage changes in the cell's membrane potential. During action potentials, they play a ...
References
Further reading
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External links
GeneReviews/NIH/NCBI/UW entry on Brugada syndrome*
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