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.
Orio P, Rojas P, Ferreira G, Latorre R (Aug 2002). "New disguises for an old channel: MaxiK channel beta-subunits". News in Physiological Sciences. 17: 156–61. doi:10.1152/nips.01387.2002. PMID12136044.
Knaus HG, Folander K, Garcia-Calvo M, Garcia ML, Kaczorowski GJ, Smith M, Swanson R (Jun 1994). "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. PMID8006036.
Meera P, Wallner M, Jiang Z, Toro L (Mar 1996). "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. doi:10.1016/0014-5793(96)00151-2. PMID8612769.
Dworetzky SI, Boissard CG, Lum-Ragan JT, McKay MC, Post-Munson DJ, Trojnacki JT, Chang CP, Gribkoff VK (Aug 1996). "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. PMID8764643.
Valverde MA, Rojas P, Amigo J, Cosmelli D, Orio P, Bahamonde MI, Mann GE, Vergara C, Latorre R (Sep 1999). "Acute activation of Maxi-K channels (hSlo) by estradiol binding to the beta subunit". Science. 285 (5435): 1929–31. doi:10.1126/science.285.5435.1929. PMID10489376.
Jin P, Weiger TM, Wu Y, Levitan IB (Mar 2002). "Phosphorylation-dependent functional coupling of hSlo calcium-dependent potassium channel and its hbeta 4 subunit". The Journal of Biological Chemistry. 277 (12): 10014–20. doi:10.1074/jbc.M107682200. PMID11790768.
Greenwood IA, Miller LJ, Ohya S, Horowitz B (Jun 2002). "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. doi:10.1074/jbc.C200215200. PMID11994272.
Gollasch M, Tank J, Luft FC, Jordan J, Maass P, Krasko C, Sharma AM, Busjahn A, Bähring S (May 2002). "The BK channel beta1 subunit gene is associated with human baroreflex and blood pressure regulation". Journal of Hypertension. 20 (5): 927–33. doi:10.1097/00004872-200205000-00028. PMID12011654.
Jin P, Weiger TM, Levitan IB (Nov 2002). "Reciprocal modulation between the alpha and beta 4 subunits of hSlo calcium-dependent potassium channels". The Journal of Biological Chemistry. 277 (46): 43724–9. doi:10.1074/jbc.M205795200. PMID12223479.
Mazzone JN, Kaiser RA, Buxton IL (2003). "Calcium-activated potassium channel expression in human myometrium: effect of pregnancy". Proceedings of the Western Pharmacology Society. 45: 184–6. PMID12434576.
Kudlacek PE, Pluznick JL, Ma R, Padanilam B, Sansom SC (Aug 2003). "Role of hbeta1 in activation of human mesangial BK channels by cGMP kinase". American Journal of Physiology. Renal Physiology. 285 (2): F289–94. doi:10.1152/ajprenal.00046.2003. PMID12670831.
Ransom CB, Liu X, Sontheimer H (Jun 2003). "Current transients associated with BK channels in human glioma cells". The Journal of Membrane Biology. 193 (3): 201–13. doi:10.1007/s00232-003-2019-7. PMID12962281.
Hartness ME, Brazier SP, Peers C, Bateson AN, Ashford ML, Kemp PJ (Dec 2003). "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. doi:10.1074/jbc.M309463200. PMID14522958.