KCNMA1
Encyclopedia
Calcium-activated potassium channel subunit alpha-1 also known as potassium large conductance calcium-activated channel, subfamily M, alpha member 1 (KCa1.1) is a voltage gated ion channel
encoded by the KCNMA1 gene
.
which are fundamental to the control of smooth muscle tone and neuronal excitability.
, KCNMB2
, KCNMB3
, or KCNMB4
) can associate with the tetrametic channel. Alternatively spliced transcript variants encoding different isoforms have been identified.
Each KCa1.1 channel alpha subunit consists of (from N- to C-terminal):
Available X-ray structures: - Crystal Structure of the Human BK Gating Apparatus - Structure of the Intracellular Gating Ring from the Human High-conductance Ca2+ gated K+ Channel (BK Channel)
Ion channel
Ion channels are pore-forming proteins that help establish and control the small voltage gradient across the plasma membrane of cells by allowing the flow of ions down their electrochemical gradient. They are present in the membranes that surround all biological cells...
encoded by the KCNMA1 gene
Gene
A gene is a molecular unit of heredity of a living organism. It is a name given to some stretches of DNA and RNA that code for a type of protein or for an RNA chain that has a function in the organism. Living beings depend on genes, as they specify all proteins and functional RNA chains...
.
Function
KCa1.1 channels are large conductance, voltage and calcium-sensitive potassium channelsCalcium-activated potassium channel
Calcium-activated potassium channels are divided into BK channels, IK channels, and SK channels based on their conductance ....
which are fundamental to the control of smooth muscle tone and neuronal excitability.
Structure
KCa1.1 channels have a tetrameric structure. Each monomer of the channel-forming alpha subunit is the product of the KCNMA1 gene. Modulatory beta subunits (encoded by KCNMB1KCNMB1
Calcium-activated potassium channel subunit beta-1 is a protein that in humans is encoded by the KCNMB1 gene.-Further reading:...
, KCNMB2
KCNMB2
Calcium-activated potassium channel subunit beta-2 is a protein that in humans is encoded by the KCNMB2 gene.MaxiK channels are large conductance, voltage and calcium-sensitive potassium channels which are fundamental to the control of smooth muscle tone and neuronal excitability...
, KCNMB3
KCNMB3
Calcium-activated potassium channel subunit beta-3 is a protein that in humans is encoded by the KCNMB3 gene.-Further reading:...
, or KCNMB4
KCNMB4
Calcium-activated potassium channel subunit beta-4 is a protein that in humans is encoded by the KCNMB4 gene.-Further reading:...
) can associate with the tetrametic channel. Alternatively spliced transcript variants encoding different isoforms have been identified.
Each KCa1.1 channel alpha subunit consists of (from N- to C-terminal):
- A unique transmembrane domain (S0) that precedes the 6 transmembrane domains (S1-S6) conserved in all voltage-dependent K+ channels.
- A voltage sensing domain (S1-S4).
- A K+ channel pore domain (S5, selectivity filter, and S6).
- A cytoplasmic C-terminal domain (CTD) consisting of a pair of RCK domains that assemble into an octameric gating ring on the intracellular side of the tetrameric channel. The CTD contains four primary binding sites for Ca2+, called "calcium bowls", encoded within the second RCK domain of each monomer.
Available X-ray structures: - Crystal Structure of the Human BK Gating Apparatus - Structure of the Intracellular Gating Ring from the Human High-conductance Ca2+ gated K+ Channel (BK Channel)