ATP-sensitive inward rectifier potassium channel 10 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 ''KCNJ10''
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 ...
.
Function
This gene encodes a member of the inward rectifier-type potassium channel family, K
ir4.1, characterized by having a greater tendency to allow potassium to flow into, rather than out of, a cell. K
ir4.1, may form a heterodimer with another potassium channel protein and may be responsible for the potassium buffering action of glial cells in the brain. Mutations in this gene have been associated with seizure susceptibility of common idiopathic generalized epilepsy syndromes.
EAST syndrome
Humans with
mutation
In biology, a mutation is an alteration in the nucleic acid sequence of the genome of an organism, virus, or extrachromosomal DNA. Viral genomes contain either DNA or RNA. Mutations result from errors during DNA or viral replication, ...
s in the KCNJ10 gene that cause
loss of function in related K
+ channels can display
Epilepsy
Epilepsy is a group of Non-communicable disease, non-communicable Neurological disorder, neurological disorders characterized by a tendency for recurrent, unprovoked Seizure, seizures. A seizure is a sudden burst of abnormal electrical activit ...
,
Ataxia
Ataxia (from Greek α- negative prefix+ -τάξις rder= "lack of order") is a neurological sign consisting of lack of voluntary coordination of muscle movements that can include gait abnormality, speech changes, and abnormalities in e ...
,
Sensorineural deafness
Sensorineural hearing loss (SNHL) is a type of hearing loss in which the root cause lies in the inner ear, sensory organ (cochlea and associated structures), or the vestibulocochlear nerve (Cranial nerves, cranial nerve VIII). SNHL accounts for a ...
and
Tubulopathy, the
EAST syndrome (
Gitelman syndrome
Gitelman syndrome (GS) is an autosomal recessive kidney tubule disorder characterized by low blood levels of potassium and magnesium, decreased excretion of calcium in the urine, and elevated blood pH. It is the most frequent hereditary salt-l ...
phenotype) reflecting roles for KCNJ10 gene products in the brain,
inner ear
The inner ear (internal ear, auris interna) is the innermost part of the vertebrate ear. In vertebrates, the inner ear is mainly responsible for sound detection and balance. In mammals, it consists of the bony labyrinth, a hollow cavity in the ...
and
kidney
In humans, the kidneys are two reddish-brown bean-shaped blood-filtering organ (anatomy), organs that are a multilobar, multipapillary form of mammalian kidneys, usually without signs of external lobulation. They are located on the left and rig ...
.
The K
ir4.1 channel is expressed in the
Stria vascularis
The stria vascularis of the cochlear duct is a capillary loop in the upper portion of the spiral ligament (the outer wall of the cochlear duct or scala media). It produces endolymph for the scala media in the cochlea.
Structure
The stria vascu ...
and is essential for formation of the
endolymph
Endolymph is the fluid contained in the membranous labyrinth of the inner ear. The major cation in endolymph is potassium, with the values of sodium and potassium concentration in the endolymph being 0.91 mM and 154 mM, respectively. ...
, the fluid that surrounds the
mechanosensitive stereocilia
Stereocilia (or stereovilli or villi) are non-motile apical cell modifications. They are distinct from cilia and microvilli, but are closely related to microvilli. They form single "finger-like" projections that may be branched, with normal cel ...
of the sensory
hair cell
Hair cells are the sensory receptors of both the auditory system and the vestibular system in the ears of all vertebrates, and in the lateral line organ of fishes. Through mechanotransduction, hair cells detect movement in their environment. ...
s that make
hearing
Hearing, or auditory perception, is the ability to perceive sounds through an organ, such as an ear, by detecting vibrations as periodic changes in the pressure of a surrounding medium. The academic field concerned with hearing is auditory sci ...
possible.
Rett Syndrome
Rett syndrome
Rett syndrome (RTT) is a genetic disorder that typically becomes apparent after 6–18 months of age and almost exclusively in girls. Symptoms include impairments in language and coordination, and repetitive movements. Those affected often h ...
is a neurological disorder characterized by a mutation in the MeCP2 gene. This mutation results in less MeCP2. KCNJ10 expression is upregulated by the transcription factor MeCP2. MeCP2 deficiency leads to less Kir4.1 channels present on astrocytes in the brain. Since there are fewer channels allowing potassium into the cells, extracellular potassium levels are higher. Higher extracellular potassium leaves neurons more easily excitable which could contribute to the epilepsy observed in many Rett Syndrome patients.
Interactions
KCNJ10 has been shown to
interact with
Interleukin 16.
See also
*
Inward-rectifier potassium ion channel
Inward-rectifier potassium channels (Kir, IRK) are a specific Lipid-gated_ion_channels, lipid-gated subset of potassium channels. To date, seven subfamilies have been identified in various mammalian cell types, plants, and bacteria. They are acti ...
References
Further reading
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External links
GeneReviews/NCBI/NIH/UW entry on Pendred Syndrome/DFNB4*
Ion channels
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