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8.A.14.1.1
Sloβ auxiliary subunit; also called KCMNB4, of 210 aas and 2 TMSs (Behrens et al. 2000).  94% identical to the human ortholog. It is a regulatory subunit of the calcium activated potassium KCNMA1 (maxiK) channel as it modulates the calcium sensitivity and gating kinetics of KCNMA1 (Brenner et al. 2000). It decreases the gating kinetics and calcium sensitivity of the KCNMA1 channel, but with fast deactivation kinetics. It may also decrease KCNMA1 channel openings at low calcium concentrations but increases channel openings at high calcium concentrations. beta4 also makes the KCNMA1 channel resistant to 100 nM charybdotoxin (CTX) toxin concentrations (Meera et al. 2000). It's 3-d structure in complex with Slo1 shows it forms a tetramer on the periphery of Slo1 (see TC# 1.A.1.3.10; Tao and MacKinnon 2019).

Accession Number:Q9JIN6
Protein Name:Slo Beta Subunit aka KCNMB4
Length:210
Molecular Weight:23857.00
Species:Mus musculus (Mouse) [10090]
Number of TMSs:2
Location1 / Topology2 / Orientation3: Membrane1 / Multi-pass membrane protein2
Substrate NONE

Cross database links:

Genevestigator: Q9JIN6
HEGENOM: HBG716488
RefSeq: NP_067427.1   
Entrez Gene ID: 58802   
Pfam: PF03185   
KEGG: mmu:58802   

Gene Ontology

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

References (2)

[1] “A novel nervous system beta subunit that downregulates human large conductance calcium-dependent potassium channels.”  Weiger T.M.et.al.   10804197
[2] “The status, quality, and expansion of the NIH full-length cDNA project: the Mammalian Gene Collection (MGC).”  The MGC Project Teamet.al.   15489334

External Searches:

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  • 2° Structure (Network Protein Sequence Analysis)

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Predict TMSs (Predict number of transmembrane segments)
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FASTA formatted sequence
1:	MAKLRVSYEY TEAEDKSIRL GLFLIVSGIL SLFIFGFCWL SPALQDLQAT AANCTVLSVQ 
61:	QIGEVFECTF TCGTDCRGTS QYPCVQVYVN NSESNSRALL HSDQHQLLTN PKCSYIPPCK 
121:	RENQKNSESV MNWQQYWKDE IGSQPFTCYF NQHQRPEDVL LQRTHDEIAL LHCFLWPVVA 
181:	FVVGVLIVVL TICAKSLAVK AEAMKKRKFS