Calcium-Gated Potassium Channel Mthk (Mthk) (MTH1520) Methanothermobacter Thermautotrophicus Recombinant Protein

KCNMA1: 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). Defects in KCNMA1 are the cause of generalized epilepsy and paroxysmal dyskinesia (GEPD). Epilepsy is one of the most common and debilitating neurological disorders. Paroxysmal dyskinesias are neurological disorders characterized by sudden, unpredictable, disabling attacks of involuntary movement often requiring life-long treatment. The coexistence of epilepsy and paroxysmal dyskinesia in the same individual or family is an increasingly recognized phenomenon. Patients manifest absence seizures, generalized tonic-clonic seizures, paroxysmal nonkinesigenic dyskinesia, involuntary dystonic or choreiform movements. Onset is usually in childhood and patients may have seizures only, dyskinesia only, or both. Belongs to the potassium channel family. Calcium- activated (TC 1.A.1.3) subfamily. KCa1.1/KCNMA1 sub-subfamily. 7 isoforms of the human protein are produced by alternative splicing.

Protein type: Endoplasmic reticulum; Membrane protein, integral; Membrane protein, multi-pass; Channel, potassium

Cellular Component: endoplasmic reticulum membrane; voltage-gated potassium channel complex; protein complex; cell; endoplasmic reticulum; dendrite; integral to membrane; terminal button; caveola; postsynaptic membrane; cell soma; perinuclear region of cytoplasm; apical plasma membrane; cytoplasm; plasma membrane; presynaptic active zone membrane; external side of plasma membrane

Molecular Function: protein binding; voltage-gated potassium channel activity; calcium-activated potassium channel activity; protein homodimerization activity; potassium channel activity; metal ion binding; large conductance calcium-activated potassium channel activity; protein complex binding; actin binding

Biological Process: circadian rhythm; relaxation of vascular smooth muscle; positive regulation of apoptosis; regulation of vasodilation; cell maturation; generation of action potential; auditory receptor cell differentiation; adult walking behavior; cellular potassium ion homeostasis; vasodilation; response to corticosteroid stimulus; protein homotetramerization; synaptic transmission; locomotor rhythm; sensory perception of sound; neuromuscular process controlling balance; protein homooligomerization; potassium ion transport; regulation of aldosterone metabolic process; eye blink reflex; response to osmotic stress; micturition; regulation of membrane potential; smooth muscle contraction involved in micturition; response to estrogen stimulus; response to hypoxia; response to calcium ion; negative regulation of cell volume; saliva secretion; response to pH