Hmdb loader
Identification
HMDB Protein ID HMDBP13658
Secondary Accession Numbers None
Name Calcium-activated potassium channel subunit alpha-1
Synonyms
  1. BK channel
  2. BKCA alpha
  3. Calcium-activated potassium channel, subfamily M subunit alpha-1
  4. K(VCA)alpha
  5. KCa1.1
  6. Maxi K channel
  7. Slo-alpha
  8. Slo1
  9. Slowpoke homolog
  10. MaxiK
  11. mSlo1
  12. Slo homolog
  13. mSlo
Gene Name KCNMA1
Protein Type Unknown
Biological Properties
General Function Not Available
Specific Function Potassium channel activated by both membrane depolarization or increase in cytosolic Ca(2+) that mediates export of K(+). It is also activated by the concentration of cytosolic Mg(2+). Its activation dampens the excitatory events that elevate the cytosolic Ca(2+) concentration and/or depolarize the cell membrane. It therefore contributes to repolarization of the membrane potential. Plays a key role in controlling excitability in a number of systems, such as regulation of the contraction of smooth muscle, the tuning of hair cells in the cochlea, regulation of transmitter release, and innate immunity. In smooth muscles, its activation by high level of Ca(2+), caused by ryanodine receptors in the sarcoplasmic reticulum, regulates the membrane potential. In cochlea cells, its number and kinetic properties partly determine the characteristic frequency of each hair cell and thereby helps to establish a tonotopic map. Kinetics of KCNMA1 channels are determined by alternative splicing, phosphorylation status and its combination with modulating beta subunits. Highly sensitive to both iberiotoxin (IbTx) and charybdotoxin (CTX).
Pathways
  • cGMP-PKG signaling pathway
  • Insulin secretion
  • Pancreatic secretion
  • Renin secretion
  • Salivary secretion
  • Vascular smooth muscle contraction
Reactions Not Available
GO Classification
Biological Process
sensory perception of sound
neuromuscular process controlling balance
regulation of membrane potential
positive regulation of apoptotic process
locomotor rhythm
neuronal action potential
response to calcium ion
vasodilation
response to pH
cell maturation
adult walking behavior
relaxation of vascular smooth muscle
blood vessel diameter maintenance
cellular potassium ion homeostasis
eye blink reflex
inner ear auditory receptor cell differentiation
micturition
negative regulation of cell volume
negative regulation of small intestine smooth muscle contraction
regulation of aldosterone metabolic process
regulation of ion transmembrane transport
response to carbon monoxide
response to corticosteroid
saliva secretion
response to hypoxia
positive regulation of neuron apoptotic process
smooth muscle contraction involved in micturition
circadian rhythm
potassium ion transport
synaptic transmission
response to osmotic stress
response to estrogen stimulus
Cellular Component
protein-containing complex
cytoplasm
endoplasmic reticulum
plasma membrane
dendrite
perinuclear region of cytoplasm
postsynaptic membrane
terminal button
voltage-gated potassium channel complex
caveola
presynaptic active zone membrane
glutamatergic synapse
neuronal cell body
apical plasma membrane
external side of plasma membrane
integral component of presynaptic active zone membrane
integral to membrane
Molecular Function
actin binding
protein-containing complex binding
metal ion binding
calcium-activated potassium channel activity
voltage-gated potassium channel activity
large conductance calcium-activated potassium channel activity
ligand-gated ion channel activity involved in regulation of presynaptic membrane potential
potassium channel activity
identical protein binding
Cellular Location Not Available
Gene Properties
Chromosome Location Not Available
Locus Not Available
SNPs Not Available
Gene Sequence Not Available
Protein Properties
Number of Residues 1209
Molecular Weight 134394.8
Theoretical pI 7.151
Pfam Domain Function
Signals Not Available
Transmembrane Regions
  • 87-107;179-199;215-235;240-260;265-285;301-321;368-388;
Protein Sequence Not Available
GenBank ID Protein Not Available
UniProtKB/Swiss-Prot ID Q08460
UniProtKB/Swiss-Prot Entry Name KCMA1_MOUSE
PDB IDs Not Available
GenBank Gene ID Not Available
GeneCard ID Not Available
GenAtlas ID Not Available
HGNC ID Not Available
References
General References
  1. Pallanck L, Ganetzky B: Cloning and characterization of human and mouse homologs of the Drosophila calcium-activated potassium channel gene, slowpoke. Hum Mol Genet. 1994 Aug;3(8):1239-43. [PubMed:7987297 ]
  2. Weiger TM, Holmqvist MH, Levitan IB, Clark FT, Sprague S, Huang WJ, Ge P, Wang C, Lawson D, Jurman ME, Glucksmann MA, Silos-Santiago I, DiStefano PS, Curtis R: A novel nervous system beta subunit that downregulates human large conductance calcium-dependent potassium channels. J Neurosci. 2000 May 15;20(10):3563-70. [PubMed:10804197 ]
  3. Huttlin EL, Jedrychowski MP, Elias JE, Goswami T, Rad R, Beausoleil SA, Villen J, Haas W, Sowa ME, Gygi SP: A tissue-specific atlas of mouse protein phosphorylation and expression. Cell. 2010 Dec 23;143(7):1174-89. doi: 10.1016/j.cell.2010.12.001. [PubMed:21183079 ]
  4. Butler A, Tsunoda S, McCobb DP, Wei A, Salkoff L: mSlo, a complex mouse gene encoding "maxi" calcium-activated potassium channels. Science. 1993 Jul 9;261(5118):221-4. doi: 10.1126/science.7687074. [PubMed:7687074 ]
  5. Liu J, Asuncion-Chin M, Liu P, Dopico AM: CaM kinase II phosphorylation of slo Thr107 regulates activity and ethanol responses of BK channels. Nat Neurosci. 2006 Jan;9(1):41-9. doi: 10.1038/nn1602. Epub 2005 Dec 11. [PubMed:16341213 ]
  6. Shipston MJ, Duncan RR, Clark AG, Antoni FA, Tian L: Molecular components of large conductance calcium-activated potassium (BK) channels in mouse pituitary corticotropes. Mol Endocrinol. 1999 Oct;13(10):1728-37. doi: 10.1210/mend.13.10.0355. [PubMed:10517674 ]
  7. Cui J, Aldrich RW: Allosteric linkage between voltage and Ca(2+)-dependent activation of BK-type mslo1 K(+) channels. Biochemistry. 2000 Dec 19;39(50):15612-9. doi: 10.1021/bi001509+. [PubMed:11112549 ]
  8. Bao L, Rapin AM, Holmstrand EC, Cox DH: Elimination of the BK(Ca) channel's high-affinity Ca(2+) sensitivity. J Gen Physiol. 2002 Aug;120(2):173-89. doi: 10.1085/jgp.20028627. [PubMed:12149279 ]
  9. Shi J, Krishnamoorthy G, Yang Y, Hu L, Chaturvedi N, Harilal D, Qin J, Cui J: Mechanism of magnesium activation of calcium-activated potassium channels. Nature. 2002 Aug 22;418(6900):876-80. doi: 10.1038/nature00941. [PubMed:12192410 ]
  10. Xia XM, Zeng X, Lingle CJ: Multiple regulatory sites in large-conductance calcium-activated potassium channels. Nature. 2002 Aug 22;418(6900):880-4. doi: 10.1038/nature00956. [PubMed:12192411 ]
  11. Sokolowski S, Harvey M, Sakai Y, Jordan A, Sokolowski B: The large conductance calcium-activated K(+) channel interacts with the small GTPase Rab11b. Biochem Biophys Res Commun. 2012 Sep 21;426(2):221-5. doi: 10.1016/j.bbrc.2012.08.067. Epub 2012 Aug 21. [PubMed:22935415 ]