Calcium-activated potassium channel beta subunit
solution structure of the cytoplasmic n-terminus of the bk beta-subunit kcnmb2
The functional diversity of potassium channels can arise through homo- or hetero-associations of alpha subunits or association with auxiliary cytoplasmic beta subunits. The beta subunit (which is thought to possess 2 transmembrane domains) increases the calcium sensitivity of the BK channel. It does this by enhancing the time spent by the channel in burst-like open states. However, it has little effect on the durations of closed intervals between bursts, or on the numbers of open and closed states entered during gating.
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- Nimigean CM, Magleby KL (March 1999). "The beta subunit increases the Ca2+ sensitivity of large conductance Ca2+-activated potassium channels by retaining the gating in the bursting states". J. Gen. Physiol. 113 (3): 425–40. doi:10.1085/jgp.113.3.425. PMC 2222905. PMID 10051518.