New modulatory alpha subunits for mammalian Shab K+ channels.
Two novel K+ channel alpha subunits, named Kv9.1 and Kv9.2, have been cloned. The Kv9.2 gene is situated in the 8q22 region of the chromosome. mRNAs for these two subunits are highly and selectively expressed in the nervous system. High levels of expressions are found in the olfactory bulb, cerebral cortex, hippocampal formation, habenula, basolateral amygdaloid nuclei, and cerebellum. Interestingly Kv9.1 and Kv9.2 colocalized with Kv2.1 and/or Kv2.2 alpha subunits in several regions of the brain. Neither Kv9.1 nor Kv9.2 have K+ channel activity by themselves, but both modulate the activity of Kv2.1 and Kv2.2 channels by changing kinetics and levels of expression and by shifting the half-inactivation potential to more polarized values. This report also analyzes the changes in electrophysiological properties of Kv2 subunits induced by Kv5.1 and Kv6.1, two other modulatory subunits. Each modulatory subunit has its own specific properties of regulation of the functional Kv2 subunits, and they can lead to extensive inhibitions, to large changes in kinetics, and/or to large shifts in the voltage dependencies of the inactivation process. The increasing number of modulatory subunits for Kv2.1 and Kv2.2 provides an amazingly new capacity of functional diversity.
Salinas
M
M
Institut de Pharmacologie Moléculaire et Cellulaire, CNRS, 660 route des Lucioles, Sophia Antipolis, 06560 Valbonne, France.
Duprat
F
F
Heurteaux
C
C
Hugnot
J P
JP
Lazdunski
M
M
D000595:Amino Acid Sequence; D000818:Animals; D001921:Brain / Q000378:metabolism; D019556:COS Cells; D003001:Cloning, Molecular; D018076:DNA, Complementary; D005455:Fluorescent Antibody Technique; D015640:Ion Channel Gating; D051379:Mice; D008969:Molecular Sequence Data; D010766:Phosphorylation; D010802:Phylogeny; D015221:Potassium Channels / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D024642:Potassium Channels, Voltage-Gated; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D017386:Sequence Homology, Amino Acid
D018076:DNA, Complementary; C503457:Kcns1 protein, mouse; C108429:Kcns2 protein, mouse; D015221:Potassium Channels; D024642:Potassium Channels, Voltage-Gated; D012333:RNA, Messenger