Large conductance calcium dependent potassium ion channel beta 4 subunit
Maxi K channel subunit beta 4
Maxi K channel subunit beta-4
Potassium large conductance calcium activated channel subfamily M beta member 4
Slo beta 4
subfamily M subunit beta-4
Regulatory subunit of the calcium activated potassium KCNMA1 (maxiK) channel. Modulates the calcium sensitivity and gating kinetics of KCNMA1, thereby contributing to KCNMA1 channel diversity. Decreases the gating kinetics and calcium sensitivity of the KCNMA1 channel, but with fast deactivation kinetics. May decrease KCNMA1 channel openings at low calcium concentrations but increases channel openings at high calcium concentrations. Makes KCNMA1 channel resistant to 100 nM charybdotoxin (CTX) toxin concentrations.
Predominantly expressed in brain. In brain, it is expressed in the cerebellum, cerebral cortex, medulla, spinal cord, occipital pole, frontal lobe, temporal lobe, putamen, amygdala, caudate nucleus, corpus callosum, hippocampus, substantia nigra and thalamus. Weakly or not expressed in other tissues.
Belongs to the KCNMB (TC 8.A.14.1) family. KCNMB4 subfamily.
Resistance to charybdotoxin (CTX) toxin is mediated by the extracellular domain.
Phosphorylated. Phosphorylation modulates its effect on KCNMA1 activation kinetics. N-glycosylated. A highly glycosylated form is promoted by KCNMA1. Glycosylation, which is not required for the interaction with KCNMA1 and subcellular location, increases protection against charybdotoxin.