BK channel

General Information (Source: NCBI Gene,UniProt)

Text mining Term	BK channel
UniProt ID	KCMA1_RAT
Name	MaxiK K(VCA)alpha Slo1 BKCA alpha Slowpoke homolog Calcium-activated potassium channel, subfamily M subunit alpha-1 Slo-alpha BK channel Calcium-activated potassium channel subunit alpha-1 Maxi K channel Slo homolog KCa1.1
Gene Names	Kcnma1 Synonyms:Kcnma
Taxonomy	Rattus norvegicus

General annotation

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).
Subcellular location	Cell membrane; Multi-pass membrane protein. Isoform 7: Endoplasmic reticulum membrane; Multi-pass membrane protein. Note=Has a dominant-negative effect on other isoforms, preventing their localization to the cell membrane.

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).

Subcellular location

Cell membrane; Multi-pass membrane protein. Isoform 7: Endoplasmic reticulum membrane; Multi-pass membrane protein. Note=Has a dominant-negative effect on other isoforms, preventing their localization to the cell membrane.

Gene Ontology

GO:0005789	endoplasmic reticulum membrane	CC
GO:0005249	voltage-gated potassium channel activity	MF
GO:0005515	protein binding	MF
GO:0015269	calcium-activated potassium channel activity	MF
GO:0008076	voltage-gated potassium channel complex	CC
GO:0000166	nucleotide binding	MF
GO:0046872	metal ion binding	MF

Sequence

>gi|13929184|ref|NP_114016.1| calcium-activated potassium channel subunit alpha-1 [Rattus norvegicus]
MANGGGGGGGGSSGSSGGGGGGGGGETALRMSSNIHANHLSLDASSSSSSSSSSSSSSSSSVHEPKMDAL
IIPVTMEVPCDSRGQRMWWAFLASSMVTFFGGLFIILLWRTLKYLWTVCCHCGGKTKEAQKINNGSSQAD
GTLKPVDEKEEVVAAEVGWMTSVKDWAGVMISAQTLTGRVLVVLVFALSIGALVIYFIDSSNPIESCQNF
YKDFTLQIDMAFNVFFLLYFGLRFIAANDKLWFWLEVNSVVDFFTVPPVFVSVYLNRSWLGLRFLRALRL
IQFSEILQFLNILKTSNSIKLVNLLSIFISTWLTAAGFIHLVENSGDPWENFQNNQALTYWECVYLLMVT
MSTVGYGDVYAKTTLGRLFMVFFILGGLAMFASYVPEIIELIGNRKKYGGSYSAVSGRKHIVVCGHITLE
SVSNFLKDFLHKDRDDVNVEIVFLHNISPNLELEALFKRHFTQVEFYQGSVLNPHDLARVKIESADACLI
LANKYCADPDAEDASNIMRVISIKNYHPKIRIITQMLQYHNKAHLLNIPSWNWKEGDDAICLAELKLGFI
AQSCLAQGLSTMLANLFSMRSFIKIEEDTWQKYYLEGVSNEMYTEYLSSAFVGLSFPTVCELCFVKLKLL
MIAIEYKSANRESRSRKRILINPGNHLKTQEGTLGFFIASDAKEVKRAFFYCKACHDDVTDPKRIKKCGC
RRLIYSKMSIYKRMSRACCFDCGRSERDCSCMSGRVRGNVDTLERNFPLSSVSVNDCSTSFRAFEDEQPP
TLSPKKKQRNGGMRNSPNTSPKLMRHDPLLIPGNDQIDNMDSNVKKYDSTGMFHWCAPKEIEKVILTRSE
AAMTVLSGHVVVCIFGDVSSALIGLRNLVMPLRASNFHYHELKHIVFVGSIEYLKREWETLHNFPKVSIL
PGTPLSRADLRAVNINLCDMCVILSANQNNIDDTSLQDKECILASLNIKSMQFDDSIGVLQANSQGFTPP
GMDRSSPDNSPVHGMLRQPSITTGVNIPIITELVNDTNVQFLDQDDDDDPDTELYLTQPFACGTAFAVSV
LDSLMSATYFNDNILTLIRTLVTGGATPELEALIAEENALRGGYSTPQTLANRDRCRVAQLALLDGPFAD
LGDGGCYGDLFCKALKTYNMLCFGIYRLRDAHLSTPSQCTKRYVITNPPYEFELVPTDLIFCLMQFDHNA
GQSRASLSHSSHSSQSSSKKSSSVHSIPSTANRPNRPKSRESRDKQKKEMVYR

Database Cross Reference

Ensembl Gene
UniGene	Rn.30616
PDB
RefSeq	NP_114016.1
Pfam	PF00520 PF02254 PF03493

PTID

BK channel

General Information (Source: NCBI Gene,UniProt)

General annotation

Gene Ontology

Sequence

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Database Cross Reference