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8.A.14.1.3
Auxillary β-subunit (β2) of voltage-dependent and Ca2+ sensitive K+ channel (MaxiK; 1.A.1.3.2) The increased current reduces excitability (Wallner et al., 1999). 44% identical to TC#8.A.14.1.4). Full=BK channel subunit beta-2; Short=BKbeta2; Short=Hbeta2; AltName: Full=Calcium-activated potassium channel, subfamily M subunit beta-2; AltName: Full=Charybdotoxin receptor subunit beta-2; AltName: Full=Hbeta3; AltName: Full=K(VCA)beta-2; AltName: Full=Maxi K channel subunit beta-2; AltName: Full=Slo-beta-2. Coexpression of KCNMB2 with the human pore-forming alpha subunit of the large conductance voltage and Ca2+-activated K+ channel (hSlo) yields inactivating currents similar to those observed in hippocampal neurons.  β2 not only influences hSlo currents but also limits hSlo surface expression levels via an endocytic mechanism (Zarei et al. 2007).

Accession Number:Q9Y691
Protein Name:Calcium-activated potassium channel subunit beta 2 aka β2
Length:235
Molecular Weight:27130.00
Species:Homo sapiens (Human) [9606]
Number of TMSs:2
Location1 / Topology2 / Orientation3: Membrane1 / Multi-pass membrane protein2
Substrate NONE

Cross database links:

Genevestigator: Q9Y691
eggNOG: prNOG05609
RefSeq: NP_005823.1    NP_852006.1   
Entrez Gene ID: 10242   
Pfam: PF03185    PF09303   
Drugbank: Drugbank Link   
OMIM: 605214  gene
KEGG: hsa:10242   

Gene Ontology

GO:0008076 C:voltage-gated potassium channel complex
GO:0015269 F:calcium-activated potassium channel activity
GO:0008200 F:ion channel inhibitor activity
GO:0015459 F:potassium channel regulator activity
GO:0005513 P:detection of calcium ion
GO:0006813 P:potassium ion transport
GO:0019228 P:regulation of action potential in neuron
GO:0019229 P:regulation of vasoconstriction

References (8)

[1] “Molecular basis of fast inactivation in voltage and Ca2+-activated K+ channels: a transmembrane beta-subunit homolog.”  Wallner M.et.al.   10097176
[2] “Cloning and functional characterization of novel large conductance calcium-activated potassium channel beta subunits, hKCNMB3 and hKCNMB4.”  Brenner R.et.al.   10692449
[3] “The status, quality, and expansion of the NIH full-length cDNA project: the Mammalian Gene Collection (MGC).”  The MGC Project Teamet.al.   15489334
[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.et.al.   10377337
[5] “A neuronal beta subunit (KCNMB4) makes the large conductance, voltage- and Ca2+-activated K+ channel resistant to charybdotoxin and iberiotoxin.”  Meera P.et.al.   10792058
[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.et.al.   12566540
[7] “New disguises for an old channel: MaxiK channel beta-subunits.”  Orio P.et.al.   12136044
[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.et.al.   11517232
Structure:
1JO6     

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Predict TMSs (Predict number of transmembrane segments)
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FASTA formatted sequence
1:	MFIWTSGRTS SSYRHDEKRN IYQKIRDHDL LDKRKTVTAL KAGEDRAILL GLAMMVCSIM 
61:	MYFLLGITLL RSYMQSVWTE ESQCTLLNAS ITETFNCSFS CGPDCWKLSQ YPCLQVYVNL 
121:	TSSGEKLLLY HTEETIKINQ KCSYIPKCGK NFEESMSLVN VVMENFRKYQ HFSCYSDPEG 
181:	NQKSVILTKL YSSNVLFHSL FWPTCMMAGG VAIVAMVKLT QYLSLLCERI QRINR