Ca+2-activated K+ channel subunit beta-1; BK channel subunit beta-1; BKbeta; BKbeta1; Hbeta1; Ca+2-activated K+ channel, subfamily M subunit beta-1; Ca+2-activated K+ channel subunit beta; charybdotoxin receptor subunit beta-1; K(VCA)beta-1; Maxi K channel subunit beta-1; Slo-beta-1; Slo-beta (KCNMB1)

Function

• regulatory subunit of the Ca+2-activated K+ channel KCNMA1
• modulates the Ca+2 sensitivity & gating kinetics of KCNMA1, thereby contributing to KCNMA1 channel diversity
• increases the apparent Ca+2/voltage sensitivity of the KCNMA1 channel
• modifies KCNMA1 channel kinetics & alters its pharmacological properties
• slows down the activation & the deactivation kinetics of the channel
• acts as a negative regulator of smooth muscle contraction by enhancing the Ca+2 sensitivity of KCNMA1
• required for internal binding of the KCNMA1 channel opener dehydrosoyasaponin I (DHS-1) triterpene glycoside & for external binding of the agonist hormone 17-beta-estradiol
• increases binding of charybdotoxin (CTX) toxin to KCNMA1
• interacts with KCNMA1 tetramer
• probably 4 molecules of KCMNB1 per KCNMA1 tetramer

Structure

• N-glycosylated
• belongs to the KCNMB (TC 8.A.14.1) family, KCNMB1 subfamily

Compartment

membrane

Alternative splicing

named isoforms=2

Expression

• abundantly expressed in smooth muscle
• low levels of expression in most other tissues
• within the brain, relatively high levels found in hippocampus & corpus callosum

Polymorphism

• genetic variation in KCNMB1 can influence the severity of diastolic hypertension

More general terms

• transmembrane 2 protein
• K+ channel subfamily M
• glycoprotein

Component of

• Ca+2-activated K+ channel

Database

• Entrez gene: http://www.ncbi.nlm.nih.gov/sites/entrez?db=gene&cmd=Retrieve&dopt=Graphics&list_uids=3779
• Kegg: http://www.genome.jp/dbget-bin/www_bget?hsa:3779
• OMIM: https://mirror.omim.org/entry/603951
• OMIM: https://mirror.omim.org/entry/608622
• UniProt: http://www.uniprot.org/uniprot/Q16558.html