Potassium calcium-activated channel subfamily M regulatory beta subunit 4 (KCNMB4)

Potassium calcium-activated channel subfamily M regulatory beta subunit 4 (KCNMB4) is a regulatory auxiliary subunit of the large-conductance voltage- and calcium-activated potassium (BK, KCa1.1) channel complex[1][3]. This subunit modulates the kinetics and calcium sensitivity of the central pore-forming KCNMA1 (BK alpha) subunit, leading to a slowdown in channel activation/deactivation and altered channel responsiveness to intracellular calcium[1][3][4]. KCNMB4 is especially important in neuronal tissues, where it helps shape neuronal excitability and impacts neurotransmission and spike timing[6]. Mutations or altered expression of KCNMB4 have been associated with neurological diseases such as paroxysmal nonkinesigenia dyskinesia and hypomagnesemia[1]. While charybdotoxin and related compounds interact with the channel, KCNMB4 makes the BK channel resistant to nanomolar concentrations of this blocker[3], highlighting its importance in pharmacological responses. KCNMB4 and the broader BK channel complex are being investigated as therapeutic targets in neurological, cardiovascular, and renal disorders due to their key roles in cellular excitability, though specific KCNMB4-targeted drugs are not yet established[2][3].

Other names

Calcium-activated potassium channel subunit beta-4BK channel beta subunit 4BKbeta4Hbeta4Maxi K channel subunit beta-4Slo-beta-4MaxiK channel beta-subunit 4big potassium channel beta subunit 4charybdotoxin receptor subunit beta-4potassium channel subfamily M regulatory beta subunit 4

Modulation of ion channel gating: Alters calcium sensitivity and voltage range of BK (KCNMA1) channel activation; Shifts channel opening potential, affects kinetics, and pharmacological sensitivity