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Protein KCNMB2 PDB 1jo6.png
Available structures
PDBOrtholog search: PDBe RCSB
AliasesKCNMB2, potassium calcium-activated channel subfamily M regulatory beta subunit 2
External IDsMGI: 1919663 HomoloGene: 4257 GeneCards: KCNMB2
Gene location (Human)
Chromosome 3 (human)
Chr.Chromosome 3 (human)[1]
Chromosome 3 (human)
Genomic location for KCNMB2
Genomic location for KCNMB2
Band3q26.32Start178,272,932 bp[1]
End178,844,429 bp[1]
RNA expression pattern
PBB GE KCNMB2 221097 s at fs.png
More reference expression data
RefSeq (mRNA)



RefSeq (protein)



Location (UCSC)Chr 3: 178.27 – 178.84 MbChr 3: 31.9 – 32.2 Mb
PubMed search[3][4]
View/Edit HumanView/Edit Mouse
KCNMB2, ball and chain domain
PDB 1jo6 EBI.jpg
solution structure of the cytoplasmic n-terminus of the bk beta-subunit kcnmb2

Calcium-activated potassium channel subunit beta-2 is a protein that in humans is encoded by the KCNMB2 gene.[5][6]

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 contain two distinct subunits: a pore-forming alpha subunit and a modulatory beta subunit. Each complete MaxiK channel contains four copies of the pore-forming alpha subunit and up to four beta subunits. The protein encoded by the KCNMB2 gene is an auxiliary beta subunit which influences the calcium sensitivity of MaxiK currents and, following activation of MaxiK current, causes persistent inactivation. The subunit encoded by the KCNMB2 gene is expressed in various endocrine cells, including pancreas and adrenal chromaffin cells. It is also found in the brain, including the hippocampus. The KCNMB2 gene is homologous to three other genes found in mammalian genomes: KCNMB1 (found primarily in smooth muscle), KCNMB3, and KCNMB4 (the primary brain MaxiK auxiliary subunit).[6]

Calcium-activated potassium channel subunit beta-2 comprises two domains. An N-terminal cytoplasmic domain, the ball and chain domain, which is responsible for the fast inactivation of these channels,[7] and a C-terminal calcium-activated potassium channel beta subunit domain. The N-terminal domain only occurs in calcium-activated potassium channel subunit beta-2, while the C-terminal domain is found in related proteins.

See also[edit]


  1. ^ a b c GRCh38: Ensembl release 89: ENSG00000197584 - Ensembl, May 2017
  2. ^ a b c GRCm38: Ensembl release 89: ENSMUSG00000037610 - Ensembl, May 2017
  3. ^ "Human PubMed Reference:".
  4. ^ "Mouse PubMed Reference:".
  5. ^ Wallner M, Meera P, Toro L (May 1999). "Molecular basis of fast inactivation in voltage and Ca2+-activated K+ channels: a transmembrane beta-subunit homolog". Proc Natl Acad Sci U S A. 96 (7): 4137–42. doi:10.1073/pnas.96.7.4137. PMC 22433. PMID 10097176.
  6. ^ a b "Entrez Gene: KCNMB2 potassium large conductance calcium-activated channel, subfamily M, beta member 2".
  7. ^ Bentrop D, Beyermann M, Wissmann R, Fakler B (November 2001). "NMR structure of the "ball-and-chain" domain of KCNMB2, the beta 2-subunit of large conductance Ca2+- and voltage-activated potassium channels". J. Biol. Chem. 276 (45): 42116–21. doi:10.1074/jbc.M107118200. PMID 11517232.

Further reading[edit]

External links[edit]

This article incorporates text from the United States National Library of Medicine, which is in the public domain.

This article incorporates text from the public domain Pfam and InterPro: IPR015382