KCNMA1 / BK Antibody – Rabbit Polyclonal

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]

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

Chromosomal Location of Human Ortholog: 10q22.3

Cellular Component: apical plasma membrane; caveola; endoplasmic reticulum; external side of plasma membrane; integral to membrane; plasma membrane; postsynaptic membrane; terminal button; voltage-gated potassium channel complex

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

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

Disease: Generalized Epilepsy And Paroxysmal Dyskinesia