Description
Product Characteristics: Function: Potassium channel activated by both membrane depolarization or increase in cytosolic Ca(2+) that mediates export of K(+). 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). The protein was initially thought to contain two functionally distinct parts: The core channel (from the N-terminus to the S9 segment) that mediates the channel activity, and the cytoplasmic tail (from the S9 segment to the C-terminus) that mediates the calcium sensing. The situation is however more complex, since the core channel also contains binding sites for Ca(2+) and Mg(2+). Subcellular location: Membrane, Multi-pass membrane protein. Tissue specificity: Widely expressed. Except in myocytes, it is almost ubiquitously expressed.,Calcium-activated,Potassium channel subfamily M subunit alpha 1, Calcium-activated potassium channel subunit alpha-1, Calcium-activated potassium channel, subfamily M subunit alpha-1, Maxi K channel, MaxiK, BK channel, K(VCA)alpha, BKCA alpha, KCa1.1, Slowpoke homolog, Slo homolog, Slo-alpha, Slo1, Slo
Target Information: MaxiK channels are large conductance, voltage and calcium-sensitive potassium channels which are fundamental to the control of smooth muscle tone and neuronal excitability. MaxiK channels can be formed by 2 subunits: the pore-forming alpha subunit, which is the product of this gene, and the modulatory beta subunit. Intracellular calcium regulates the physical association between the alpha and beta subunits. Alternatively spliced transcript variants encoding different isoforms have been identified. [provided by RefSeq, Jul 2008]