Potassium Large Conductance Calcium Activated Channel Subfamily M Beta 1 (KCNMb1)

SLO-beta, is widely expressed as a 1.4-kb transcript throughout human tissues. Coexpression of the SLO-alpha and -beta subunits in Xenopus oocytes or mammalian cells gave rise to calcium-activated potassium currents with a pronounced increase in calcium and/or voltage sensitivity. the concentration of intracellular calcium controls the functional coupling between beta and alpha subunits of the MaxiK channel complex, switching the alpha subunit from a calcium-independent to a calcium-dependent mode and from a beta subunit dull interaction to a beta subunit-activated mode. The functional switch develops at concentrations of calcium that occur during cellular excitation, providing the molecular basis for how MaxiK channels regulate smooth muscle excitability and neurotransmitter release.