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KCa4.1

Family: Calcium-activated potassium channels

Contents:
Gene and Protein Information
Previous and Unofficial Names
Database Links
Associated Proteins
Ion Selectivity and Conductance
Voltage Dependence
Activators
Gating Inhibitors
Pore Blockers
Tissue Distribution
Physiological Functions
General Comments
References
Gene and Protein Information
Species TM P Loops AA Chromosomal Location Gene Symbol Gene Name Reference
Human 6 0 1256 9q34.3 KCNT1 potassium channel, subfamily T, member 1 18
Mouse 6 0 1238 2 A3 Kcnt1 potassium channel, subfamily T, member 1 14,18,20
Rat 6 0 1237 3p13 Kcnt1 potassium channel, subfamily T, member 1 8,10
Previous and Unofficial Names
Slack
Slo2.2
KCNT1
KCa4.1
KIAA1422
Slack
rSlo2
potassium channel subfamily T member 1
potassium channel subunit (Slack)
potassium channel, subfamily T, member 1
sequence like a calcium-activated potassium channel subunit
slo2
C030030G16Rik
Database Links
Ensembl
Entrez Gene
GeneCards
GenitoUrinary Development Molecular Anatomy Project
HomoloGene
Human Protein Reference Database
InterPro
KEGG Gene
OMIM
PharmGKB Gene
PhosphoSitePlus
Protein Ontology (PRO)
RefSeq Nucleotide
RefSeq Protein
TreeFam
UniGene Hs.
UniProt
Wikipedia
Search for 3D structures on the PDB
Search by keyword: Calcium-activated potassium channels KCa4.1
Associated Proteins
Heteromeric Pore-forming Subunits
Name References
Not determined
Auxiliary Subunits
Name References
PSD-95 19
Slo1 10
KCa1.1 10
Other Associated Proteins
Name References
Not determined
Ion Selectivity and Conductance
Species:  Mouse
Rank order:  K+ > Na+ [5.0 pS]
References:  15,23
Species:  Rat
Rank order:  K+
References:  10
Species:  Rat
Macroscopic current rectification:  Inward
References:  10
Species:  Mouse
Macroscopic current rectification:  Inward
References:  15
Species:  Mouse
Macroscopic current rectification:  Inward
References:  23
Voltage Dependence Comments
Experiment in Xenopus ooctyes showed weak voltage-sensitivity [23]
Activators
Key to terms and symbols View all chemical structures Click column headers to sort
Ligand Sp. Affinity Units Concentration range (M) Holding voltage (mV) Reference
Na+ Rn - - 1.5x10-2 - 23
Cl- Rn - - 8x10-3 - 23
phorbol 12-myristate 13-acetate Rn 7.0 – 7.3 pEC50 - - 17
bithionol Rn 5.0 – 6.0 pEC50 - - 22
Activator Comments
Cytoplasmic Na+ works synergistically with Cl- for activation
Gating inhibitors
Key to terms and symbols View all chemical structures Click column headers to sort
Ligand Sp. Affinity Units Concentration range (M) Holding voltage (mV) Reference
Ca2+ Rn - - 0x100 - 3x10-6 - 10
Ca2+ Mm 6.52 pIC50 - - 15
bepridil Rn 5.0 – 6.0 pIC50 - - 1,22
View species-specific gating inhibitor tables
Pore Blockers
Key to terms and symbols View all chemical structures Click column headers to sort
Ligand Sp. Affinity Units Concentration range (M) Holding voltage (mV) Reference
quinidine Rn 4.04 pIC50 - - 22
tetraethylammonium Rn 1.7 – 2.0 pIC50 - - 3
Tissue Distribution
Kidney (covering the medullary and cortical thick ascending limbs of Henle’s loop)
Species:  Mouse
Technique:  RT-PCR
References:  15
Brain, Testis, Kidney
Species:  Mouse
Technique:  RT-PCR
References:  23
Brain:brainstem (red nucleus,oculomotor nucleus, mesencephalic trigeminal, trapezoid nucleus, gigantocellularius, vestibular nucleus), olfactory bulb, frontal cortex, hippocampus. Neuronal immunostaining observed in cell bodies and axonal tracts
Species:  Rat
Technique:  Immunohistochemistry
References:  2
Physiological Functions
KCNT1 is proposed to assist apical absorption of Na+ and Cl- in transport epithelium, by providing a basolateral hyperpolarizing potential, linked to increases in intracellular Na+ and Cl-.
Species:  Mouse
Tissue:  Kidney (medullary and cortical thick ascending limbs of Henle’s loop)
References:  15
KCNT1 channels are proposed to mediate a fast Na+-dependent component of after-hyperpolarizations in MNTB neurons. This permits these neurons to follow high frequency auditory input by triggering action potentials with high fidelity and precision.
Species:  Mouse
Tissue:  Medial nucleus of the trapezoid body (MNTB) in the auditory brainstem
References:  23
General Comments
KCNT1 and KCNT2 likely encode native KNa channels ([1],[5],[23]). Native KNa channels were first recorded from guinea pig cardiac myocytes ([11]), then later found widely in neurons in the vertebrate central nervous system ([6],[7],[9],[12],[13],[16],[21]) and dorsal root ganglia ([4]). KNa channels have been proposed to protect against hypoxic insult ([11]), but this and other possible functions remain to be clearly established. Interestingly, C. elegans slo-2 loss-of-function mutants are hypersensitive to hypoxic death ([23]).

REFERENCES

To cite this database page, please use the following:

Richard Aldrich, K. George Chandy, Stephan Grissmer, George A. Gutman, Aguan D. Wei, Heike Wulff.
Calcium-activated potassium channels: KCa4.1. Last modified on 01/07/2010. Accessed on 20/05/2013. IUPHAR database (IUPHAR-DB), http://www.iuphar-db.org/DATABASE/ObjectDisplayForward?objectId=385.


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