The domain within your query sequence starts at position 411 and ends at position 509; the E-value for the BK_channel_a domain shown below is 3.2e-31.



PFAM accession number:PF03493
Interpro abstract (IPR003929):

Potassium channels are the most diverse group of the ion channel family [(PUBMED:1772658), (PUBMED:1879548)]. They are important in shaping the action potential, and in neuronal excitability and plasticity [(PUBMED:2451788)]. The potassium channel family is composed of several functionally distinct isoforms, which can be broadly separated into 2 groups [(PUBMED:2555158)]: the practically non-inactivating 'delayed' group and the rapidly inactivating 'transient' group.

These are all highly similar proteins, with only small amino acid changes causing the diversity of the voltage-dependent gating mechanism, channel conductance and toxin binding properties. Each type of K+ channel is activated by different signals and conditions depending on their type of regulation: some open in response to depolarisation of the plasma membrane; others in response to hyperpolarisation or an increase in intracellular calcium concentration; some can be regulated by binding of a transmitter, together with intracellular kinases; while others are regulated by GTP-binding proteins or other second messengers [(PUBMED:2448635)]. In eukaryotic cells, K+ channels are involved in neural signalling and generation of the cardiac rhythm, act as effectors in signal transduction pathways involving G protein-coupled receptors (GPCRs) and may have a role in target cell lysis by cytotoxic T-lymphocytes [(PUBMED:1373731)]. In prokaryotic cells, they play a role in the maintenance of ionic homeostasis [(PUBMED:11178249)].


BK channels (also referred to as high-conductance, maxi-K channels or Slo family channels) [(PUBMED:17115074)] are widely expressed in the body, being found in glandular tissue, smooth and skeletal muscle, as well as in neural tissues. They have been demonstrated to regulate arteriolar and airway diameter, and also neurotransmitter release. Each channel complex is thought to be composed of 2 types of subunit; the pore-forming (alpha) subunits and smaller accessory (beta) subunits.

The alpha subunit of the BK channel was initially thought to share the characteristic 6TM organisation of the voltage-gated K+ channels. However, the molecule is now thought to possess an additional TM domain, with an extracellular N terminus and intracellular C terminus. This C-terminal region contains 4 predominantly hydrophobic domains, which are also thought to lie intracellularly. The extracellular N terminus and the first TM region are required for modulation by the beta subunit. The precise location of the Ca2+-binding site that modulates channel activation remains unknown, but it is thought to lie within the C-terminal hydrophobic domains.

The sodium-activated potassium channels Slick (Slo2.1, KCNT2) and Slack (Slo2.2, KCNT1) belong to the structurally related high-conductance potassium channels of the Slo family [(PUBMED:26587966)]. Slo3, also a member of the Slo family, isexclusively expressed in mammalian sperm [(PUBMED:23129643)].

GO process:potassium ion transport (GO:0006813)
GO component:membrane (GO:0016020)
