Modulation of Kv4.3 current by accessory subunits.
Kv4.3 encodes the pore-forming subunit of the cardiac transient outward potassium current (I(to)). hKv4.3-encoded current does not fully replicate cardiac I(to), suggesting a functionally significant role for accessory subunits. KChIP2 associates with Kv4.3 and modifies hKv4.3-encoded currents but does not replicate native I(to). We examined the effect of several ancillary subunits expressed in the heart on hKv4.3-encoded currents. Remarkably, the ancillary subunits Kvbeta(3), minK, MiRP-1, the Na channel beta(1) and KChIP2 increased the density and modified the gating of hKv4.3 current. hKv4.3 promiscuously assembles with ancillary subunits in vitro, functionally modifying the encoded currents; however, the physiological significance is uncertain.
Deschênes
Isabelle
I
Department of Medicine, Institute of Molecular Cardiobiology, Division of Cardiology, Johns Hopkins University, Baltimore, MD 21205, USA.
Tomaselli
Gordon F
GF
D002135:Calcium-Binding Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D002460:Cell Line; D006801:Humans; D066298:In Vitro Techniques; D051605:Kv Channel-Interacting Proteins; D009206:Myocardium / Q000378:metabolism; D018408:Patch-Clamp Techniques; D015221:Potassium Channels / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D024642:Potassium Channels, Voltage-Gated; D021122:Protein Subunits; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D051672:Shal Potassium Channels; D015222:Sodium Channels / Q000737:chemistry / Q000235:genetics / Q000378:metabolism
D002135:Calcium-Binding Proteins; C497021:KCND3 protein, human; C496752:KCNIP2 protein, human; D051605:Kv Channel-Interacting Proteins; D015221:Potassium Channels; D024642:Potassium Channels, Voltage-Gated; D021122:Protein Subunits; D011994:Recombinant Proteins; D051672:Shal Potassium Channels; D015222:Sodium Channels; C059983:potassium channel protein I(sk)