Q9Y691 (KCMB2_HUMAN) Reviewed, UniProtKB/Swiss-Prot

Names and origin

Protein names

Recommended name:
Calcium-activated potassium channel subunit beta-2

Alternative name(s):
BK channel subunit beta-2
Short name=BKbeta2
Short name=Hbeta2
Calcium-activated potassium channel, subfamily M subunit beta-2
Charybdotoxin receptor subunit beta-2
Hbeta3
K(VCA)beta-2
Maxi K channel subunit beta-2
Slo-beta-2

Gene names

Name:

KCNMB2

Organism

Homo sapiens (Human) [Reference proteome]

Taxonomic identifier

9606 [NCBI]

Taxonomic lineage

cellular organisms › Eukaryota › Opisthokonta › Metazoa › Eumetazoa › Bilateria › Deuterostomia › Chordata › Craniata › Vertebrata › Gnathostomata › Teleostomi › Euteleostomi › Sarcopterygii › Tetrapoda › Amniota › Mammalia › Theria › Eutheria › Euarchontoglires › Primates › Haplorrhini › Simiiformes › Catarrhini › Hominoidea › Hominidae › Homininae › Homo

Protein attributes

Sequence length	235 AA.
Sequence status	Complete.
Protein existence	Evidence at protein level

General annotation (Comments)

Function	Regulatory subunit of the calcium activated potassium KCNMA1 (maxiK) channel. Modulates the calcium sensitivity and gating kinetics of KCNMA1, thereby contributing to KCNMA1 channel diversity. Acts as a negative regulator that confers rapid and complete inactivation of KCNMA1 channel complex. May participate in KCNMA1 inactivation in chromaffin cells of the adrenal gland or in hippocampal CA1 neurons. Ref.1 Ref.4
Subunit structure	Interacts with KCNMA1 tetramer. There are probably 4 molecules of KCMNB2 per KCNMA1 tetramer. Ref.1
Subcellular location	Membrane; Multi-pass membrane protein.
Tissue specificity	Expressed in kidney, heart and brain. Highly expressed in ovary. Expressed at low level in other tissues. Ref.1 Ref.2 Ref.4
Domain	The ball and chain domain mediates the inactivation of KCNMA1. It occludes the conduction pathway of KCNMA1 channels, and comprises the pore-blocking ball domain (residues 1-17) and the chain domain (residues 20-45) linking it to the transmembrane segment. The ball domain is made up of a flexible N-terminus anchored at a well ordered loop-helix motif. The chain domain consists of a 4-turn helix with an unfolded linker at its C-terminus. Ref.1 Ref.4
Post-translational modification	N-glycosylated. Ref.5
Sequence similarities	Belongs to the KCNMB (TC 8.A.14.1) family. KCNMB2 subfamily. [View classification]

Ontologies

Keywords
Biological process	Ion transport Transport
Cellular component	Membrane
Domain	Transmembrane Transmembrane helix
Molecular function	Ion channel
PTM	Glycoprotein
Technical term	3D-structure Complete proteome Reference proteome
Gene Ontology (GO)
Biological_process	blood coagulation Traceable author statement. Source: Reactome detection of calcium ion Inferred from direct assay Ref.2. Source: UniProtKB regulation of action potential in neuron Inferred from direct assay Ref.2. Source: UniProtKB regulation of vasoconstriction Traceable author statement Ref.2. Source: UniProtKB synaptic transmission Traceable author statement. Source: Reactome
Cellular_component	voltage-gated potassium channel complex Inferred from direct assay Ref.2. Source: UniProtKB
Molecular_function	calcium-activated potassium channel activity Inferred from direct assay Ref.2. Source: UniProtKB ion channel inhibitor activity Traceable author statement Ref.1. Source: ProtInc potassium channel regulator activity Traceable author statement Ref.1. Source: ProtInc
Complete GO annotation...

Sequence annotation (Features)

Feature key

Position(s)

Length

Description

Graphical view

Feature identifier

Molecule processing

Chain

1 – 235

235

Calcium-activated potassium channel subunit beta-2

PRO_0000187051

Regions

Topological domain

1 – 46

46

Cytoplasmic Potential

Transmembrane

47 – 67

21

Helical; Name=1; Potential

Topological domain

68 – 194

127

Extracellular Potential

Transmembrane

195 – 215

21

Helical; Name=2; Potential

Topological domain

216 – 235

20

Cytoplasmic Potential

Region

1 – 45

45

Ball and chain

Amino acid modifications

Glycosylation

88

1

N-linked (GlcNAc...) Potential

Glycosylation

96

1

N-linked (GlcNAc...) Potential

Glycosylation

119

1

N-linked (GlcNAc...) Potential

Experimental info

Mutagenesis

2 – 4

3

FIW → GGG: Abolishes inactivation of KCNMA1 channel. Ref.6

Secondary structure

1

.

.

.

.

.

.

.

235

Helix Strand Turn

Details...

Beta strand

12 – 15

4

Helix

22 – 29

8

Turn

30 – 32

3

Beta strand

33 – 35

3

Sequences

	Sequence		Length	Mass (Da)
	Q9Y691 [UniParc]. Last modified November 1, 1999. Version 1. Checksum: 5752021DF27D8CF5	FASTA	235	27,130
	10 20 30 40 50 60 MFIWTSGRTS SSYRHDEKRN IYQKIRDHDL LDKRKTVTAL KAGEDRAILL GLAMMVCSIM 70 80 90 100 110 120 MYFLLGITLL RSYMQSVWTE ESQCTLLNAS ITETFNCSFS CGPDCWKLSQ YPCLQVYVNL 130 140 150 160 170 180 TSSGEKLLLY HTEETIKINQ KCSYIPKCGK NFEESMSLVN VVMENFRKYQ HFSCYSDPEG 190 200 210 220 230 NQKSVILTKL YSSNVLFHSL FWPTCMMAGG VAIVAMVKLT QYLSLLCERI QRINR

References

	« Hide 'large scale' referencesShow 'large scale' references »
[1]	"Molecular basis of fast inactivation in voltage and Ca2+-activated K+ channels: a transmembrane beta-subunit homolog." Wallner M., Meera P., Toro L. Proc. Natl. Acad. Sci. U.S.A. 96:4137-4142(1999) [PubMed] [Europe PMC] [Abstract] Cited for: NUCLEOTIDE SEQUENCE [MRNA], FUNCTION, DOMAIN, TISSUE SPECIFICITY, INTERACTION WITH KCNMA1. Tissue: Neuroepithelium.
[2]	"Cloning and functional characterization of novel large conductance calcium-activated potassium channel beta subunits, hKCNMB3 and hKCNMB4." Brenner R., Jegla T.J., Wickenden A., Liu Y., Aldrich R.W. J. Biol. Chem. 275:6453-6461(2000) [PubMed] [Europe PMC] [Abstract] Cited for: NUCLEOTIDE SEQUENCE [MRNA], TISSUE SPECIFICITY. Tissue: Ovary.
[3]	"The status, quality, and expansion of the NIH full-length cDNA project: the Mammalian Gene Collection (MGC)." The MGC Project Team Genome Res. 14:2121-2127(2004) [PubMed] [Europe PMC] [Abstract] Cited for: NUCLEOTIDE SEQUENCE [LARGE SCALE MRNA]. Tissue: Embryonic testis.
[4]	"Molecular basis for the inactivation of Ca2+- and voltage-dependent BK channels in adrenal chromaffin cells and rat insulinoma tumor cells." Xia X.-M., Ding J.-P., Lingle C.J. J. Neurosci. 19:5255-5264(1999) [PubMed] [Europe PMC] [Abstract] Cited for: FUNCTION, DOMAIN, TISSUE SPECIFICITY.
[5]	"A neuronal beta subunit (KCNMB4) makes the large conductance, voltage- and Ca2+-activated K+ channel resistant to charybdotoxin and iberiotoxin." Meera P., Wallner M., Toro L. Proc. Natl. Acad. Sci. U.S.A. 97:5562-5567(2000) [PubMed] [Europe PMC] [Abstract] Cited for: GLYCOSYLATION.
[6]	"Inactivation of BK channels by the NH2 terminus of the beta2 auxiliary subunit: an essential role of a terminal peptide segment of three hydrophobic residues." Xia X.-M., Ding J.-P., Lingle C.J. J. Gen. Physiol. 121:125-148(2003) [PubMed] [Europe PMC] [Abstract] Cited for: MUTAGENESIS OF 2-PHE--TRP-4.
[7]	"New disguises for an old channel: MaxiK channel beta-subunits." Orio P., Rojas P., Ferreira G., Latorre R. News Physiol. Sci. 17:156-161(2002) [PubMed] [Europe PMC] [Abstract] Cited for: REVIEW.
[8]	"NMR structure of the 'ball-and-chain' domain of KCNMB2, the beta 2-subunit of large conductance Ca2+- and voltage-activated potassium channels." Bentrop D., Beyermann M., Wissmann R., Fakler B. J. Biol. Chem. 276:42116-42121(2001) [PubMed] [Europe PMC] [Abstract] Cited for: STRUCTURE BY NMR OF 1-45.
+	Additional computationally mapped references.

Cross-references

Sequence databases

EMBL
GenBank
DDBJ

AF099137 mRNA. Translation: AAD23380.1.
AF209747 mRNA. Translation: AAF36562.1.
BC017825 mRNA. Translation: AAH17825.1.

IPI

IPI00411546.

RefSeq

NP_005823.1. NM_005832.3.
NP_852006.1. NM_181361.1.

UniGene

Hs.478368.

3D structure databases

PDBe
RCSB PDB
PDBj

Entry	Method	Resolution (Å)	Chain	Positions	PDBsum
1JO6	NMR	-	A	1-45	[»]

ProteinModelPortal

Q9Y691.

ModBase

Search...

Protein-protein interaction databases

STRING

9606.ENSP00000351068.

Protein family/group databases

TCDB

8.A.14.1.3. Ca2+-activated K+ channel auxiliary subunit slowpoke-beta (Slobeta) family.

PTM databases

PhosphoSite

Q9Y691.

Polymorphism databases

DMDM

46396054.

Proteomic databases

PaxDb

Q9Y691.

PRIDE

Q9Y691.

Protocols and materials databases

DNASU

10242.

StructuralBiologyKnowledgebase

Search...

Genome annotation databases

Ensembl

ENST00000358316; ENSP00000351068; ENSG00000197584.
ENST00000420517; ENSP00000408252; ENSG00000197584.
ENST00000432997; ENSP00000407592; ENSG00000197584.
ENST00000452583; ENSP00000397483; ENSG00000197584.

GeneID

10242.

KEGG

hsa:10242.

UCSC

uc003fjd.3. human.

Organism-specific databases

CTD

10242.

GeneCards

GC03P177990.

HGNC

HGNC:6286. KCNMB2.

HPA

CAB022649.

MIM

605214. gene.

neXtProt

NX_Q9Y691.

PharmGKB

PA30066.

GenAtlas

Search...

Phylogenomic databases

eggNOG

NOG44064.

HOVERGEN

HBG052223.

InParanoid

Q9Y691.

KO

K04938.

OMA

VWTEEAQ.

OrthoDB

EOG4V438P.

PhylomeDB

Q9Y691.

Enzyme and pathway databases

Reactome

REACT_13685. Neuronal System.
REACT_604. Hemostasis.

Gene expression databases

ArrayExpress

Q9Y691.

Bgee

Q9Y691.

CleanEx

HS_KCNMB2.

Genevestigator

Q9Y691.

GermOnline

ENSG00000197584. Homo sapiens.

Family and domain databases

Gene3D

4.10.81.20. 1 hit.

InterPro

IPR003930. K_chnl_Ca-activ_BK_bsu.
IPR015382. KCNMB2_ball_chain_dom.
[Graphical view]

PANTHER

PTHR10258. PTHR10258. 1 hit.

Pfam

PF03185. CaKB. 1 hit.
PF09303. KcnmB2_inactiv. 1 hit.
[Graphical view]

PRINTS

PR01450. BKCHANNELB.

ProtoNet

Search...

Other

EvolutionaryTrace

Q9Y691.

GenomeRNAi

10242.

NextBio

38800.

SOURCE

Search...

Entry information

Entry name

KCMB2_HUMAN

Accession

Primary (citable) accession number: Q9Y691

Entry history

Integrated into UniProtKB/Swiss-Prot:	April 13, 2004
Last sequence update:	November 1, 1999
Last modified:	May 1, 2013
This is version 99 of the entry and version 1 of the sequence. [Complete history]

Entry status

Reviewed (UniProtKB/Swiss-Prot)

Annotation program

Chordata Protein Annotation Program

Disclaimer

Any medical or genetic information present in this entry is provided for research, educational and informational purposes only. It is not in any way intended to be used as a substitute for professional medical advice, diagnosis, treatment or care.