Calcium-activated potassium channel subunit alpha-1

Calcium-activated potassium channel subunit alpha-1

Potassium channel activated by both membrane depolarization or increase in cytosolic Ca(2+) that mediates export of K(+)14523450,29330545,31152168. It is also activated by the concentration of cytosolic Mg(2+). Its activation dampens the excitatory events that elevate the cytosolic Ca(2+) concentration and/or depolarize the cell membrane. It therefore contributes to repolarization of the membrane potential. Plays a key role in controlling excitability in a number of systems, such as regulation of the contraction of smooth muscle, the tuning of hair cells in the cochlea, regulation of transmitter release, and innate immunity. In smooth muscles, its activation by high level of Ca(2+), caused by ryanodine receptors in the sarcoplasmic reticulum, regulates the membrane potential. In cochlea cells, its number and kinetic properties partly determine the characteristic frequency of each hair cell and thereby helps to establish a tonotopic map. Kinetics of KCNMA1 channels are determined by alternative splicing, phosphorylation status and its combination with modulating beta subunits. Highly sensitive to both iberiotoxin (IbTx) and charybdotoxin (CTX). Possibly induces sleep when activated by melatonin and through melatonin receptor MTNR1A-dependent dissociation of G-beta and G-gamma subunits, leading to increased sensitivity to Ca(2+) and reduced synaptic transmission32958651

Potassium channel activated by both membrane depolarization or increase in cytosolic Ca(2+) that mediates export of K(+)

Quoted from UniProt’s FUNCTION annotation for Q12791 (reviewed). The superscript numbers are UniProt’s own PubMed citations, kept in the sentence and in order, each linking to the paper it names.

What it acts with

STRING’s highest-confidence human functional partners. The combined score mixes several kinds of evidence, so each channel is shown separately — a partner supported by experiment is a different claim from one supported only by text mining, and for a receptor this is where its coupling appears as evidence rather than as assertion.

Where it sits in the cell

UniProt, curated Cell membrane

Expression by cell type

Single cell type RNA, the 9 highest of those the Human Protein Atlas reports for this gene. Transcript, not protein, and a cell type rather than a tissue.

• Retinal bipolar cells1,789.6 nCPM
• Salivary ionocytes1,694.7 nCPM
• Salivary acinar cells1,516.9 nCPM
• Ependymal cells1,320.9 nCPM
• Myonuclei1,079.6 nCPM
• Lacrimal acinar cells1,058 nCPM
• Oligodendrocyte progenitor cells1,022.8 nCPM
• Kupffer cells870.1 nCPM
• Neutrophils829.9 nCPM