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8.A.14.1.2
Smooth muscle and brain Ca2+-activated K+ channel β-subunit, Slo-β (β1); confers increased Ca2+ and voltage sensitivity (Tseng-Crank et al., 1996). A steroid interaction site is in transmembrane domain 2 of the potassium (BK) channel accessory β-subunit (Bukiya et al., 2011). A Long-chain omega-3 polyunsaturated fatty acids such as docosahexaenoic acid (DHA), found in oily fish, lower blood pressure by activating vascular BK channels made of Slo1 β1 subunits. Neuronal Slo1 β4 channels were just as well activated by DHA as vascular Slo1 β1 channels, but the stimulatory effect of DHA was much smaller in Slo1 β2, Slo1 LRRC26 (γ1), and Slo1 channels without auxiliary subunits.  Residues responsible for this response to DHA were identified (Hoshi et al. 2013). BK beta1 TMS2 is necessary for this subunit to enable ethanol-induced inhibition of myocyte BK channels and cerebral artery constriction at physiological Ca2+ and voltages (Kuntamallappanavar and Dopico 2017). After moderate or heavy drinking, the ethanol concentration in the blood is 30 - 60 mM.

Accession Number:Q16558
Protein Name:Calcium-activated potassium channel subunit beta 1 aka Sloβ (β1)
Length:191
Molecular Weight:21797.00
Species:Homo sapiens (Human) [9606]
Number of TMSs:2
Location1 / Topology2 / Orientation3: Membrane1 / Multi-pass membrane protein2
Substrate NONE

Cross database links:

Genevestigator: Q16558
eggNOG: prNOG08300
RefSeq: NP_004128.1   
Entrez Gene ID: 3779   
Pfam: PF03185   
OMIM: 603951  gene
608622  phenotype
KEGG: hsa:3779   

Gene Ontology

GO:0015269 F:calcium-activated potassium channel activity
GO:0015459 F:potassium channel regulator activity
GO:0006813 P:potassium ion transport
GO:0007268 P:synaptic transmission

References (10)

[1] “A calcium switch for the functional coupling between alpha (hslo) and beta subunits (KV,Ca beta) of maxi K channels.”  Meera P.et.al.   8612769
[2] “Phenotypic alteration of a human BK (hSlo) channel by hSlobeta subunit coexpression: changes in blocker sensitivity, activation/relaxation and inactivation kinetics, and protein kinase A modulation.”  Dworetzky S.I.et.al.   8764643
[3] “Cloning, expression, and distribution of a Ca(2+)-activated K+ channel beta-subunit from human brain.”  Tseng-Crank J.et.al.   8799178
[4] “Calcium-activated potassium channel expression in human myometrium: effect of pregnancy.”  Mazzone J.N.et.al.   12434576
[5] “Complete sequencing and characterization of 21,243 full-length human cDNAs.”  Ota T.et.al.   14702039
[6] “The status, quality, and expansion of the NIH full-length cDNA project: the Mammalian Gene Collection (MGC).”  The MGC Project Teamet.al.   15489334
[7] “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
[8] “Acute activation of Maxi-K channels (hSlo) by estradiol binding to the beta subunit.”  Valverde M.A.et.al.   10489376
[9] “New disguises for an old channel: MaxiK channel beta-subunits.”  Orio P.et.al.   12136044
[10] “Gain-of-function mutation in the KCNMB1 potassium channel subunit is associated with low prevalence of diastolic hypertension.”  Fernandez-Fernandez J.M.et.al.   15057310

External Searches:

  • Search: DB with
  • BLAST ExPASy (Swiss Institute of Bioinformatics (SIB) BLAST)
  • CDD Search (Conserved Domain Database)
  • Search COGs (Clusters of Orthologous Groups of proteins)
  • 2° Structure (Network Protein Sequence Analysis)

Analyze:

Predict TMSs (Predict number of transmembrane segments)
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FASTA formatted sequence
1:	MVKKLVMAQK RGETRALCLG VTMVVCAVIT YYILVTTVLP LYQKSVWTQE SKCHLIETNI 
61:	RDQEELKGKK VPQYPCLWVN VSAAGRWAVL YHTEDTRDQN QQCSYIPGSV DNYQTARADV 
121:	EKVRAKFQEQ QVFYCFSAPR GNETSVLFQR LYGPQALLFS LFWPTFLLTG GLLIIAMVKS 
181:	NQYLSILAAQ K