KvLQT1
Encyclopedia
Kv7.1 is a potassium
channel
protein
coded for by the gene
KCNQ1. Kv7.1 is present in the cell membrane
s of cardiac muscle tissue and in inner ear neuron
s among other tissues. In the cardiac cell
s, Kv7.1 mediates the IKs (or slow delayed rectifying K+) current that contributes to the repolarization
of the cell, terminating the cardiac action potential
and thereby the heart's contraction
.
Mutation
s in the gene can lead to a defective protein and several forms of inherited arrhythmias as Long QT syndrome
, Short QT syndrome
, and Familial Atrial Fibrillation. Currents arising from Kv7.1 in over-expression systems have never been recapitulated in native tissues - Kv7.1 is always found in native tissues with a modulatory subunit. In cardiac tissue, these subunits comprise KCNE1 and yotiao. Though physiologically
irrelevant, homotetrameric Kv7.1 channels also display a unique form of C-type inactivation that reaches equilibrium quickly, allowing KvLQT1 currents to plateau. This is different from the inactivation seen in A-type currents, which causes rapid current decay.
with PRKACA
, PPP1CA
and AKAP9
.
Potassium
Potassium is the chemical element with the symbol K and atomic number 19. Elemental potassium is a soft silvery-white alkali metal that oxidizes rapidly in air and is very reactive with water, generating sufficient heat to ignite the hydrogen emitted in the reaction.Potassium and sodium are...
channel
Ion channel
Ion channels are pore-forming proteins that help establish and control the small voltage gradient across the plasma membrane of cells by allowing the flow of ions down their electrochemical gradient. They are present in the membranes that surround all biological cells...
protein
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...
coded for by the 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...
KCNQ1. Kv7.1 is present in the cell membrane
Cell membrane
The cell membrane or plasma membrane is a biological membrane that separates the interior of all cells from the outside environment. The cell membrane is selectively permeable to ions and organic molecules and controls the movement of substances in and out of cells. It basically protects the cell...
s of cardiac muscle tissue and in inner ear neuron
Neuron
A neuron is an electrically excitable cell that processes and transmits information by electrical and chemical signaling. Chemical signaling occurs via synapses, specialized connections with other cells. Neurons connect to each other to form networks. Neurons are the core components of the nervous...
s among other tissues. In the cardiac cell
Cell (biology)
The cell is the basic structural and functional unit of all known living organisms. It is the smallest unit of life that is classified as a living thing, and is often called the building block of life. The Alberts text discusses how the "cellular building blocks" move to shape developing embryos....
s, Kv7.1 mediates the IKs (or slow delayed rectifying K+) current that contributes to the repolarization
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...
of the cell, terminating the cardiac 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...
and thereby the heart's contraction
Muscle contraction
Muscle fiber generates tension through the action of actin and myosin cross-bridge cycling. While under tension, the muscle may lengthen, shorten, or remain the same...
.
Mutation
Mutation
In molecular biology and genetics, mutations are changes in a genomic sequence: the DNA sequence of a cell's genome or the DNA or RNA sequence of a virus. They can be defined as sudden and spontaneous changes in the cell. Mutations are caused by radiation, viruses, transposons and mutagenic...
s in the gene can lead to a defective protein and several forms of inherited arrhythmias as Long QT syndrome
Long QT syndrome
The long QT syndrome is a rare inborn heart condition in which delayed repolarization of the heart following a heartbeat increases the risk of episodes of torsade de pointes . These episodes may lead to palpitations, fainting and sudden death due to ventricular fibrillation...
, Short QT syndrome
Short QT syndrome
Short QT syndrome is a genetic disease of the electrical system of the heart. It consists of a constellation of signs and symptoms, consisting of a short QT interval on an EKG that does not significantly change with heart rate, tall and peaked T waves, and a structurally normal heart...
, and Familial Atrial Fibrillation. Currents arising from Kv7.1 in over-expression systems have never been recapitulated in native tissues - Kv7.1 is always found in native tissues with a modulatory subunit. In cardiac tissue, these subunits comprise KCNE1 and yotiao. Though physiologically
Physiology
Physiology is the science of the function of living systems. This includes how organisms, organ systems, organs, cells, and bio-molecules carry out the chemical or physical functions that exist in a living system. The highest honor awarded in physiology is the Nobel Prize in Physiology or...
irrelevant, homotetrameric Kv7.1 channels also display a unique form of C-type inactivation that reaches equilibrium quickly, allowing KvLQT1 currents to plateau. This is different from the inactivation seen in A-type currents, which causes rapid current decay.
Interactions
KvLQT1 has been shown to interactProtein-protein interaction
Protein–protein interactions occur when two or more proteins bind together, often to carry out their biological function. Many of the most important molecular processes in the cell such as DNA replication are carried out by large molecular machines that are built from a large number of protein...
with PRKACA
PRKACA
cAMP-dependent protein kinase catalytic subunit alpha is an enzyme that in humans is encoded by the PRKACA gene.-Interactions:PRKACA has been shown to interact with Phosphoinositide-dependent kinase-1, IQGAP1, KvLQT1 and Ryanodine receptor 2....
, PPP1CA
PPP1CA
Serine/threonine-protein phosphatase PP1-alpha catalytic subunit is an enzyme that in humans is encoded by the PPP1CA gene.-Interactions:...
and AKAP9
AKAP9
A-kinase anchor protein 9 is an enzyme that in humans is encoded by the AKAP9 gene.-Interactions:AKAP9 has been shown to interact with Calmodulin 1, FNBP1, CALM2, Protein kinase N1, TRIP10, KvLQT1 and PRKAR2A.-Further reading:...
.