Biology:KCNMB2

Short description: Protein-coding gene in the species Homo sapiens

Generic protein structure example

KCNMB2, ball and chain domain
solution structure of the cytoplasmic n-terminus of the bk beta-subunit kcnmb2
Identifiers
Symbol	KcnmB2_inactiv
Pfam	PF09303
InterPro	IPR015382
Available protein structures: Pfam   structures / ECOD   PDB RCSB PDB; PDBe; PDBj PDBsum structure summary

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

Big Potassium (BK) channels are large conductance, voltage and calcium-sensitive potassium channels which are fundamental to the control of smooth muscle tone and neuronal excitability. BK channels can contain two distinct subunits: a pore-forming alpha subunit and a modulatory beta subunit. Each complete BK 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 BK currents and, following activation of BK 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 BK auxiliary subunit).

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, 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

• BK channel
• Voltage-gated potassium channel

Further reading

• "New disguises for an old channel: MaxiK channel beta-subunits". News Physiol. Sci. 17 (4): 156–61. 2002. doi:10.1152/nips.01387.2002. PMID 12136044. 
• "Molecular basis for the inactivation of Ca2+- and voltage-dependent BK channels in adrenal chromaffin cells and rat insulinoma tumor cells". J. Neurosci. 19 (13): 5255–64. 1999. doi:10.1523/JNEUROSCI.19-13-05255.1999. PMID 10377337. 
• "Cloning and functional characterization of novel large conductance calcium-activated potassium channel beta subunits, hKCNMB3 and hKCNMB4". J. Biol. Chem. 275 (9): 6453–61. 2000. doi:10.1074/jbc.275.9.6453. PMID 10692449. 
• "HIV-1 gp120 and chemokines activate ion channels in primary macrophages through CCR5 and CXCR4 stimulation". Proc. Natl. Acad. Sci. U.S.A. 97 (9): 4832–7. 2000. doi:10.1073/pnas.090521697. PMID 10758170. Bibcode: 2000PNAS...97.4832L. 
• "Cloning and functional expression of two families of beta-subunits of the large conductance calcium-activated K+ channel". J. Biol. Chem. 275 (30): 23211–8. 2000. doi:10.1074/jbc.M910187199. PMID 10766764. 
• "A neuronal beta subunit (KCNMB4) makes the large conductance, voltage- and Ca2+-activated K+ channel resistant to charybdotoxin and iberiotoxin". Proc. Natl. Acad. Sci. U.S.A. 97 (10): 5562–7. 2000. doi:10.1073/pnas.100118597. PMID 10792058. Bibcode: 2000PNAS...97.5562M. 
• "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. 2001. doi:10.1074/jbc.M107118200. PMID 11517232. 
• "Generation and initial analysis of more than 15,000 full-length human and mouse cDNA sequences". Proc. Natl. Acad. Sci. U.S.A. 99 (26): 16899–903. 2003. doi:10.1073/pnas.242603899. PMID 12477932. Bibcode: 2002PNAS...9916899M. 
• "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". J. Gen. Physiol. 121 (2): 125–48. 2003. doi:10.1085/jgp.20028667. PMID 12566540. 
• "Post-transcriptional control of human maxiK potassium channel activity and acute oxygen sensitivity by chronic hypoxia". J. Biol. Chem. 278 (51): 51422–32. 2004. doi:10.1074/jbc.M309463200. PMID 14522958. 
• "The status, quality, and expansion of the NIH full-length cDNA project: the Mammalian Gene Collection (MGC)". Genome Res. 14 (10B): 2121–7. 2004. doi:10.1101/gr.2596504. PMID 15489334. 
• "Structural determinants for functional coupling between the beta and alpha subunits in the Ca2+-activated K+ (BK) channel". J. Gen. Physiol. 127 (2): 191–204. 2006. doi:10.1085/jgp.200509370. PMID 16446507. 
• "BK channels with beta3a subunits generate use-dependent slow afterhyperpolarizing currents by an inactivation-coupled mechanism". J. Neurosci. 27 (17): 4707–15. 2007. doi:10.1523/JNEUROSCI.0758-07.2007. PMID 17460083. 
• "Endocytic trafficking signals in KCNMB2 regulate surface expression of a large conductance voltage and Ca(2+)-activated K+ channel". Neuroscience 147 (1): 80–9. 2007. doi:10.1016/j.neuroscience.2007.04.019. PMID 17521822. 

External links

• KCNMB2 human gene location in the UCSC Genome Browser.
• KCNMB2 human gene details in the UCSC Genome Browser.

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