KCNMB1 explained

Calcium-activated potassium channel subunit beta-1 is a protein that in humans is encoded by the KCNMB1 gene.^{[1] [2] [3]}

Function

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 product of this gene, the modulatory beta subunit. Intracellular calcium regulates the physical association between the alpha and beta subunits. Beta subunits (beta 1-4) are highly tissue specific in their expression, with beta-1 being present predominantly on vascular smooth muscle. Endothelial cells are not known to express beta-1 subunits. Beta-1 is also known to be expressed in urinary bladder and in some regions of the brain. Association of the beta-1 subunit with the BK channel increases the apparent Ca²⁺ sensitivity of the channel and decreases voltage dependence.^[4]

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 in Physiological Sciences . 17 . 4. 156–61 . Aug 2002 . 12136044 . 10.1152/nips.01387.2002. 10533/173696 . free .
• Knaus HG, Folander K, Garcia-Calvo M, Garcia ML, Kaczorowski GJ, Smith M, Swanson R . Primary sequence and immunological characterization of beta-subunit of high conductance Ca(2+)-activated K+ channel from smooth muscle . The Journal of Biological Chemistry . 269 . 25 . 17274–8 . Jun 1994 . 10.1016/S0021-9258(17)32551-6 . 8006036 . free .
• Meera P, Wallner M, Jiang Z, Toro L . A calcium switch for the functional coupling between alpha (hslo) and beta subunits (KV,Ca beta) of maxi K channels . FEBS Letters . 382 . 1–2 . 84–8 . Mar 1996 . 8612769 . 10.1016/0014-5793(96)00151-2 . 81684849 . 1996FEBSL.382...84M .
• Dworetzky SI, Boissard CG, Lum-Ragan JT, McKay MC, Post-Munson DJ, Trojnacki JT, Chang CP, Gribkoff VK . Phenotypic alteration of a human BK (hSlo) channel by hSlobeta subunit coexpression: changes in blocker sensitivity, activation/relaxation and inactivation kinetics, and protein kinase A modulation . The Journal of Neuroscience . 16 . 15 . 4543–50 . Aug 1996 . 8764643 . 10.1523/JNEUROSCI.16-15-04543.1996. 6579031 .
• Valverde MA, Rojas P, Amigo J, Cosmelli D, Orio P, Bahamonde MI, Mann GE, Vergara C, Latorre R . Acute activation of Maxi-K channels (hSlo) by estradiol binding to the beta subunit . Science . 285 . 5435 . 1929–31 . Sep 1999 . 10489376 . 10.1126/science.285.5435.1929 .
• Meera P, Wallner M, Toro L . A neuronal beta subunit (KCNMB4) makes the large conductance, voltage- and Ca2+-activated K+ channel resistant to charybdotoxin and iberiotoxin . Proceedings of the National Academy of Sciences of the United States of America . 97 . 10 . 5562–7 . May 2000 . 10792058 . 25868 . 10.1073/pnas.100118597 . 2000PNAS...97.5562M . free .
• Jin P, Weiger TM, Wu Y, Levitan IB . Phosphorylation-dependent functional coupling of hSlo calcium-dependent potassium channel and its hbeta 4 subunit . The Journal of Biological Chemistry . 277 . 12 . 10014–20 . Mar 2002 . 11790768 . 10.1074/jbc.M107682200 . free .
• Greenwood IA, Miller LJ, Ohya S, Horowitz B . The large conductance potassium channel beta-subunit can interact with and modulate the functional properties of a calcium-activated chloride channel, CLCA1 . The Journal of Biological Chemistry . 277 . 25 . 22119–22 . Jun 2002 . 11994272 . 10.1074/jbc.C200215200 . free .
• Gollasch M, Tank J, Luft FC, Jordan J, Maass P, Krasko C, Sharma AM, Busjahn A, Bähring S . The BK channel beta1 subunit gene is associated with human baroreflex and blood pressure regulation . Journal of Hypertension . 20 . 5 . 927–33 . May 2002 . 12011654 . 10.1097/00004872-200205000-00028 . 88440283 .
• Jin P, Weiger TM, Levitan IB . Reciprocal modulation between the alpha and beta 4 subunits of hSlo calcium-dependent potassium channels . The Journal of Biological Chemistry . 277 . 46 . 43724–9 . Nov 2002 . 12223479 . 10.1074/jbc.M205795200 . free .
• Mazzone JN, Kaiser RA, Buxton IL . Calcium-activated potassium channel expression in human myometrium: effect of pregnancy . Proceedings of the Western Pharmacology Society . 45 . 184–6 . 2003 . 12434576 .
• Kudlacek PE, Pluznick JL, Ma R, Padanilam B, Sansom SC . Role of hbeta1 in activation of human mesangial BK channels by cGMP kinase . American Journal of Physiology. Renal Physiology . 285 . 2 . F289-94 . Aug 2003 . 12670831 . 10.1152/ajprenal.00046.2003 . 3238002 .
• Qian X, Magleby KL . Beta1 subunits facilitate gating of BK channels by acting through the Ca2+, but not the Mg2+, activating mechanisms . Proceedings of the National Academy of Sciences of the United States of America . 100 . 17 . 10061–6 . Aug 2003 . 12893878 . 187764 . 10.1073/pnas.1731650100 . 2003PNAS..10010061Q . free .
• Ransom CB, Liu X, Sontheimer H . Current transients associated with BK channels in human glioma cells . The Journal of Membrane Biology . 193 . 3 . 201–13 . Jun 2003 . 12962281 . 10.1007/s00232-003-2019-7 . 20169684 .
• Hartness ME, Brazier SP, Peers C, Bateson AN, Ashford ML, Kemp PJ . Post-transcriptional control of human maxiK potassium channel activity and acute oxygen sensitivity by chronic hypoxia . The Journal of Biological Chemistry . 278 . 51 . 51422–32 . Dec 2003 . 14522958 . 10.1074/jbc.M309463200 . free .
• Fernández-Fernández JM, Tomás M, Vázquez E, Orio P, Latorre R, Sentí M, Marrugat J, Valverde MA . Gain-of-function mutation in the KCNMB1 potassium channel subunit is associated with low prevalence of diastolic hypertension . The Journal of Clinical Investigation . 113 . 7 . 1032–9 . Apr 2004 . 15057310 . 379324 . 10.1172/JCI20347 .
• Leo MD, Bannister JP, Narayanan D, Nair A, Grubbs JE, Gabrick KS, Boop FA, Jaggar JH . Dynamic regulation of β1 subunit trafficking controls vascular contractility . Proceedings of the National Academy of Sciences of the United States of America . 111 . 6 . 2361–6 . Feb 2014 . 24464482 . 10.1073/pnas.1317527111 . 3926029. 2014PNAS..111.2361L . free .
• Kuntamallappanavar G, Toro L, Dopico AM . Both transmembrane domains of BK β1 subunits are essential to confer the normal phenotype of β1-containing BK channels . PLOS ONE . 9 . 10 . e109306 . 2014 . 25275635 . 10.1371/journal.pone.0109306 . 4183656. 2014PLoSO...9j9306K . free .

Notes and References

1. Tseng-Crank J, Godinot N, Johansen TE, Ahring PK, Strøbaek D, Mertz R, Foster CD, Olesen SP, Reinhart PH . Cloning, expression, and distribution of a Ca(2+)-activated K+ channel beta-subunit from human brain . Proceedings of the National Academy of Sciences of the United States of America . 93 . 17 . 9200–5 . Aug 1996 . 8799178 . 38619 . 10.1073/pnas.93.17.9200 . 1996PNAS...93.9200T . free .
2. Jiang Z, Wallner M, Meera P, Toro L . Human and rodent MaxiK channel beta-subunit genes: cloning and characterization . Genomics . 55 . 1 . 57–67 . Jan 1999 . 9888999 . 10.1006/geno.1998.5627 .
3. Web site: Entrez Gene: KCNMB1 potassium large conductance calcium-activated channel, subfamily M, beta member 1.
4. Tano. J.-Y.. Gollasch. M.. Hypoxia and ischemia-reperfusion: a BiK contribution?. AJP: Heart and Circulatory Physiology. 307. 6. 2014. H811–H817. 0363-6135. 10.1152/ajpheart.00319.2014. 25015960.