Protein Details: KCa1.1 (large conductance calcium-activated potassium channels)

Function

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

Sequence

PDB Structures

Ligand Binding