Molecular physiology and modulation of somatodendritic A-type potassium channels.
The somatodendritic subthreshold A-type K+ current (ISA) in nerve cells is a critical component of the ensemble of voltage-gated ionic currents that determine somatodendritic signal integration. The underlying K+ channel belongs to the Shal subfamily of voltage-gated K+ channels. Most Shal channels across the animal kingdom share a high degree of structural conservation, operate in the subthreshold range of membrane potentials, and exhibit relatively fast inactivation and recovery from inactivation. Mammalian Shal K+ channels (Kv4) undergo preferential closed-state inactivation with features that are generally inconsistent with the classical mechanisms of inactivation typical of Shaker K+ channels. Here, we review (1) the physiological and genetic properties of ISA, 2 the molecular mechanisms of Kv4 inactivation and its remodeling by a family of soluble calcium-binding proteins (KChIPs) and a membrane-bound dipeptidase-like protein (DPPX), and (3) the modulation of Kv4 channels by protein phosphorylation.
Jerng
Henry H
HH
Division of Neuroscience, Baylor College of Medicine, Houston, TX 77030, USA. hjerng@cns.bcm.tmc.edu
Pfaffinger
Paul J
PJ
Covarrubias
Manuel
M
D000818:Animals; D002135:Calcium-Binding Proteins; D003712:Dendrites / Q000502:physiology*; D004152:Dipeptidyl-Peptidases and Tripeptidyl-Peptidases; D019143:Evolution, Molecular; D006801:Humans; D051605:Kv Channel-Interacting Proteins; D008564:Membrane Potentials / Q000235:genetics; D009419:Nerve Tissue Proteins / Q000235:genetics / Q000378:metabolism; D010766:Phosphorylation; D010802:Phylogeny; D015221:Potassium Channels / Q000235:genetics / Q000378:metabolism; D024642:Potassium Channels, Voltage-Gated / Q000235:genetics / Q000378:metabolism*; D017386:Sequence Homology, Amino Acid; D051672:Shal Potassium Channels
D002135:Calcium-Binding Proteins; C496750:KCNIP1 protein, human; D051605:Kv Channel-Interacting Proteins; D009419:Nerve Tissue Proteins; D015221:Potassium Channels; D024642:Potassium Channels, Voltage-Gated; D051672:Shal Potassium Channels; C557320:DPP6 protein, rat; D004152:Dipeptidyl-Peptidases and Tripeptidyl-Peptidases