KCND3
Encyclopedia
Potassium voltage-gated channel subfamily D member 3 also known as Kv4.3 is a protein
that in humans is encoded by the KCND3 gene
. It contributes to the cardiac transient outward potassium current
(Ito1), the main contributing current to the repolarizing
phase 1 of the cardiac action potential.
) 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).
Kv4.3 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
. This member includes two isoforms with different sizes, which are encoded by alternatively spliced transcript variants of this gene.
although only indirectly shown by mutations in the beta subunit KCNE3
which causes gain of function of Kv4.3.
Protein
Proteins are biochemical compounds consisting of one or more polypeptides typically folded into a globular or fibrous form, facilitating a biological function. A polypeptide is a single linear polymer chain of amino acids bonded together by peptide bonds between the carboxyl and amino groups of...
that in humans is encoded by the KCND3 gene
Gene
A gene is a molecular unit of heredity of a living organism. It is a name given to some stretches of DNA and RNA that code for a type of protein or for an RNA chain that has a function in the organism. Living beings depend on genes, as they specify all proteins and functional RNA chains...
. It contributes to the cardiac transient outward potassium current
Cardiac transient outward potassium current
The cardiac transient outward potassium current is the main contributing current to the repolarizing phase 1 of the cardiac action potential, and results from movement of potassium ions from the intracellular to the extracellular space...
(Ito1), the main contributing current to the repolarizing
Repolarization
In neuroscience, repolarization refers to the change in membrane potential that returns the membrane potential to a negative value after the depolarization phase of an action potential has just previously changed the membrane potential to a positive value. Repolarization results from the movement...
phase 1 of the cardiac action potential.
Function
Voltage-gated potassium (KvVoltage-gated potassium channel
Voltage-gated potassium channels are transmembrane channels specific for potassium and sensitive to voltage changes in the cell's membrane potential. During action potentials, they play a crucial role in returning the depolarized cell to a resting state....
) 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).
Kv4.3 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
Action potential
In physiology, an action potential is a short-lasting event in which the electrical membrane potential of a cell rapidly rises and falls, following a consistent trajectory. Action potentials occur in several types of animal cells, called excitable cells, which include neurons, muscle cells, and...
. 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 SyndromeBrugada syndrome
The Brugada syndrome is a genetic disease that is characterised by abnormal electrocardiogram findings and an increased risk of sudden cardiac death. It is named by the Spanish cardiologists Pedro Brugada and Josep Brugada...
although only indirectly shown by mutations in the beta subunit KCNE3
KCNE3
Potassium voltage-gated channel, Isk-related family, member 3, also known as KCNE3, is a protein that in humans is encoded by the KCNE3 gene.- Function :...
which causes gain of function of Kv4.3.