KCNMB4 explained

Calcium-activated potassium channel subunit beta-4 is a protein that in humans is encoded by the KCNMB4 gene.^{[1] [2]}

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.^[3]

See also

• BK channel
• Voltage-gated potassium channel

Further reading

• Orio P, Rojas P, Ferreira G, Latorre R . New disguises for an old channel: MaxiK channel beta-subunits. . News Physiol. Sci. . 17 . 4. 156–61 . 2002 . 12136044 . 10.1152/nips.01387.2002. 10533/173696 . free .
• Liu QH, Williams DA, McManus C, etal . 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 . 10758170 . 10.1073/pnas.090521697 . 18318 . 2000PNAS...97.4832L . free .
• Meera P, Wallner M, Toro L . A neuronal β 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 . 10792058 . 10.1073/pnas.100118597 . 25868 . 2000PNAS...97.5562M . free .
• Weiger TM, Holmqvist MH, Levitan IB, etal . A novel nervous system beta subunit that downregulates human large conductance calcium-dependent potassium channels . J. Neurosci. . 20 . 10 . 3563–70 . 2000 . 10804197 . 10.1523/JNEUROSCI.20-10-03563.2000 . 6772688 .
• Jin P, Weiger TM, Wu Y, Levitan IB . Phosphorylation-dependent functional coupling of hSlo calcium-dependent potassium channel and its hbeta 4 subunit . J. Biol. Chem. . 277 . 12 . 10014–20 . 2002 . 11790768 . 10.1074/jbc.M107682200 . free .
• Jin P, Weiger TM, Levitan IB . Reciprocal modulation between the alpha and beta 4 subunits of hSlo calcium-dependent potassium channels . J. Biol. Chem. . 277 . 46 . 43724–9 . 2003 . 12223479 . 10.1074/jbc.M205795200 . free .
• Strausberg RL, Feingold EA, Grouse LH, etal . 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 . 12477932 . 10.1073/pnas.242603899 . 139241 . free . 2002PNAS...9916899M .
• Gerhard DS, Wagner L, Feingold EA, etal . The Status, Quality, and Expansion of the NIH Full-Length cDNA Project: The Mammalian Gene Collection (MGC) . Genome Res. . 14 . 10B . 2121–7 . 2004 . 15489334 . 10.1101/gr.2596504 . 528928 .

Notes and References

1. Brenner R, Jegla TJ, Wickenden A, Liu Y, Aldrich RW . Cloning and functional characterization of novel large conductance calcium-activated potassium channel beta subunits, hKCNMB3 and hKCNMB4 . J Biol Chem . 275 . 9 . 6453–61 . Apr 2000 . 10692449 . 10.1074/jbc.275.9.6453 . free .
2. Behrens R, Nolting A, Reimann F, Schwarz M, Waldschutz R, Pongs O . hKCNMB3 and hKCNMB4, cloning and characterization of two members of the large-conductance calcium-activated potassium channel beta subunit family . FEBS Lett . 474 . 1 . 99–106 . Jul 2000 . 10828459 . 10.1016/S0014-5793(00)01584-2 . 32791798 . 2000FEBSL.474...99B .
3. Web site: Entrez Gene: KCNMB4 potassium large conductance calcium-activated channel, subfamily M, beta member 4.