Differential association of the auxiliary subunit Kvbeta2 with Kv1.4 and Kv4.3 K+ channels.
Kvbeta2 subunits associate with Kv1 and Kv4 K+ channels, but the basis of preferential association is not understood. For example, detergent resistance suggests stronger auxiliary subunit association with Kv4.2 than with Kv1.2, but Kvbeta2 preferentially localizes with the latter channels in brain. Here we examine the interaction of Kvbeta2 with two native binding partners in brain: Kv4.3 and Kv1.4. We show that the auxiliary subunit binds more efficiently to Kv1.4 than to Kv4.3 in mammalian cells. However, preexisting Kvbeta2 complexes with Kv1.4 and Kv4.3 have similar detergent sensitivity. Thus, preferential steady state binding may reflect a difference in initial association rather than stability. We also find that that the cytoplasmic C-terminus of Kv4.3 inhibits Kvbeta2 association. Apparently, a region proximal to the Kv4.3 pore contributes to the inefficient auxiliary subunit interaction that produces preferential binding of Kvbeta2 to Kv1 channels.
Wang
Lin
L
Department of Pharmacology, University of Pittsburgh, Pittsburgh, PA 15261, USA.
Takimoto
Koichi
K
Levitan
Edwin S
ES
D001665:Binding Sites; D002460:Cell Line; D006801:Humans; D051665:Kv1.4 Potassium Channel; D015221:Potassium Channels / Q000737:chemistry*; D024642:Potassium Channels, Voltage-Gated; D021122:Protein Subunits; D011994:Recombinant Proteins / Q000737:chemistry; D017384:Sequence Deletion; D051637:Shaker Superfamily of Potassium Channels; D051672:Shal Potassium Channels; D014162:Transfection
C496977:KCNA4 protein, human; C498948:KCNAB2 protein, human; C497018:KCND2 protein, human; C497021:KCND3 protein, human; D051665:Kv1.4 Potassium Channel; D015221:Potassium Channels; D024642:Potassium Channels, Voltage-Gated; D021122:Protein Subunits; D011994:Recombinant Proteins; D051637:Shaker Superfamily of Potassium Channels; D051672:Shal Potassium Channels