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KCNMB4 potassium calcium-activated channel subfamily M regulatory beta subunit 4 [ Homo sapiens (human) ]

Gene ID: 27345, updated on 17-Jun-2024


Official Symbol
KCNMB4provided by HGNC
Official Full Name
potassium calcium-activated channel subfamily M regulatory beta subunit 4provided by HGNC
Primary source
See related
Ensembl:ENSG00000135643 MIM:605223; AllianceGenome:HGNC:6289
Gene type
protein coding
RefSeq status
Homo sapiens
Eukaryota; Metazoa; Chordata; Craniata; Vertebrata; Euteleostomi; Mammalia; Eutheria; Euarchontoglires; Primates; Haplorrhini; Catarrhini; Hominidae; Homo
MaxiK channels are large conductance, voltage and calcium-sensitive potassium channels which are fundamental to the control of smooth muscle tone and neuronal excitability. MaxiK channels can be formed by 2 subunits: the pore-forming alpha subunit and the modulatory beta subunit. The protein encoded by this gene is an auxiliary beta subunit which slows activation kinetics, leads to steeper calcium sensitivity, and shifts the voltage range of current activation to more negative potentials than does the beta 1 subunit. [provided by RefSeq, Jul 2008]
Broad expression in brain (RPKM 7.6), adrenal (RPKM 4.7) and 15 other tissues See more
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Genomic context

See KCNMB4 in Genome Data Viewer
Exon count:
Annotation release Status Assembly Chr Location
RS_2023_10 current GRCh38.p14 (GCF_000001405.40) 12 NC_000012.12 (70366290..70434292)
RS_2023_10 current T2T-CHM13v2.0 (GCF_009914755.1) 12 NC_060936.1 (70345760..70413761)
105.20220307 previous assembly GRCh37.p13 (GCF_000001405.25) 12 NC_000012.11 (70760070..70828072)

Chromosome 12 - NC_000012.12Genomic Context describing neighboring genes Neighboring gene long intergenic non-protein coding RNA 2821 Neighboring gene CDK7 strongly-dependent group 2 enhancer GRCh37_chr12:70636499-70637698 Neighboring gene ATAC-STARR-seq lymphoblastoid active region 6658 Neighboring gene MPRA-validated peak1799 silencer Neighboring gene H3K4me1 hESC enhancer GRCh37_chr12:70650862-70651362 Neighboring gene NANOG hESC enhancer GRCh37_chr12:70652346-70652879 Neighboring gene progenitor renewal associated non-coding RNA Neighboring gene CCR4-NOT transcription complex subunit 2 Neighboring gene MPRA-validated peak1802 silencer Neighboring gene ATAC-STARR-seq lymphoblastoid silent region 4656 Neighboring gene MPRA-validated peak1805 silencer Neighboring gene MPRA-validated peak1806 silencer Neighboring gene H3K27ac-H3K4me1 hESC enhancer GRCh37_chr12:70861588-70862560 Neighboring gene uncharacterized LOC105369828 Neighboring gene RNA, U4 small nuclear 65, pseudogene Neighboring gene protein tyrosine phosphatase receptor type B

Genomic regions, transcripts, and products


  • Project title: HPA RNA-seq normal tissues
  • Description: RNA-seq was performed of tissue samples from 95 human individuals representing 27 different tissues in order to determine tissue-specificity of all protein-coding genes
  • BioProject: PRJEB4337
  • Publication: PMID 24309898
  • Analysis date: Wed Apr 4 07:08:55 2018


GeneRIFs: Gene References Into Functions

What's a GeneRIF?

HIV-1 interactions

Protein interactions

Protein Gene Interaction Pubs
Envelope surface glycoprotein gp120 env HIV-1 gp120 from both CCR5- and CXCR4-tropic HIV-1 strains opens calcium-activated potassium (K(Ca)), chloride, and calcium-permeant nonselective cation channels in macrophages; these signals are mediated by CCR5 and CXCR4 PubMed

Go to the HIV-1, Human Interaction Database


Products Interactant Other Gene Complex Source Pubs Description

General gene information


Gene Ontology Provided by GOA

Component Evidence Code Pubs
located_in plasma membrane IDA
Inferred from Direct Assay
more info
located_in plasma membrane TAS
Traceable Author Statement
more info
located_in synapse IEA
Inferred from Electronic Annotation
more info
part_of voltage-gated potassium channel complex IBA
Inferred from Biological aspect of Ancestor
more info
part_of voltage-gated potassium channel complex IDA
Inferred from Direct Assay
more info

General protein information

Preferred Names
calcium-activated potassium channel subunit beta-4
BK channel beta subunit 4
BK channel subunit beta-4
MaxiK channel beta-subunit 4
big potassium channel beta subunit 4
calcium-activated potassium channel, subfamily M subunit beta-4
charybdotoxin receptor subunit beta-4
large conductance calcium-dependent potassium ion channel beta 4 subunit
maxi K channel subunit beta-4
potassium channel subfamily M regulatory beta subunit 4
potassium large conductance calcium-activated channel, subfamily M, beta member 4

NCBI Reference Sequences (RefSeq)

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RefSeqs maintained independently of Annotated Genomes

These reference sequences exist independently of genome builds. Explain

These reference sequences are curated independently of the genome annotation cycle, so their versions may not match the RefSeq versions in the current genome build. Identify version mismatches by comparing the version of the RefSeq in this section to the one reported in Genomic regions, transcripts, and products above.

mRNA and Protein(s)

  1. NM_014505.6NP_055320.4  calcium-activated potassium channel subunit beta-4

    See identical proteins and their annotated locations for NP_055320.4

    Status: REVIEWED

    Source sequence(s)
    AC025569, BC042446
    Consensus CDS
    Q86W47, Q8IVR3, Q9NPA4, Q9P0G5
    ENSP00000258111.4, ENST00000258111.5
    Conserved Domains (1) summary
    CaKB; Calcium-activated potassium channel, beta subunit

RefSeqs of Annotated Genomes: GCF_000001405.40-RS_2023_10

The following sections contain reference sequences that belong to a specific genome build. Explain

Reference GRCh38.p14 Primary Assembly


  1. NC_000012.12 Reference GRCh38.p14 Primary Assembly

    GenBank, FASTA, Sequence Viewer (Graphics)

mRNA and Protein(s)

  1. XM_047428701.1XP_047284657.1  calcium-activated potassium channel subunit beta-4 isoform X2

  2. XM_011538188.3XP_011536490.1  calcium-activated potassium channel subunit beta-4 isoform X1

    Conserved Domains (1) summary
    CaKB; Calcium-activated potassium channel, beta subunit

Alternate T2T-CHM13v2.0


  1. NC_060936.1 Alternate T2T-CHM13v2.0

    GenBank, FASTA, Sequence Viewer (Graphics)

mRNA and Protein(s)

  1. XM_054371752.1XP_054227727.1  calcium-activated potassium channel subunit beta-4 isoform X2

  2. XM_054371751.1XP_054227726.1  calcium-activated potassium channel subunit beta-4 isoform X1