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MGP004967

UniProt Annotations

Entry Information

Gene Name	potassium channel subfamily M regulatory beta subunit 4
Protein Entry	KCMB4_HUMAN
UniProt ID	Q86W47
Species	Human

Comments

Comment type	Description
Domain	Resistance to charybdotoxin (CTX) toxin is mediated by the extracellular domain.
Function	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. {ECO:0000269\|PubMed:10692449, ECO:0000269\|PubMed:10792058, ECO:0000269\|PubMed:10828459}.
Miscellaneous	Treatment with okadaic acid reduces its effect on KCNMA1.
Ptm	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. {ECO:0000269\|PubMed:10792058, ECO:0000269\|PubMed:12223479}.
Ptm	Phosphorylated. Phosphorylation modulates its effect on KCNMA1 activation kinetics. {ECO:0000269\|PubMed:11790768}.
Similarity	Belongs to the KCNMB (TC 8.A.14.1) family. KCNMB4 subfamily. {ECO:0000305}.
Subcellular Location	Membrane; Multi-pass membrane protein.
Subunit	Interacts with KCNMA1 tetramer. There are probably 4 molecules of KCMNB4 per KCNMA1 tetramer. {ECO:0000269\|PubMed:10692449, ECO:0000269\|PubMed:10804197}.
Tissue Specificity	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. {ECO:0000269\|PubMed:10692449, ECO:0000269\|PubMed:10828459}.