KChIP2 modulates the cell surface expression of Kv1.5-encoded K channels

PKC and AMPK regulation of Kv1.5 potassium channels

“…Kv1.5 b-subunits alter both voltage-dependence of activation and slow and fast inactivation components 9,10 while KChIP subunits reduce the cell surface expression of Kv1.5 channels without changing current kinetics. 11 Protein kinase A has been reported to down-regulate Kv1.5 current through phosphorylation of Kvb1.3, 12 an accessory subunit which has a profound effect on the Kv1.5 current kinetics. Several studies have revealed that protein kinase C (PKC) modify the current kinetics of Kv1.5 through phosphorylation of either Kvb1.2 13,14 or Kvb1.3.…”

Electrophysiological characterization of three non-synonymous single nucleotide polymorphisms (R87Q, A251T, and P307S) found in hKv1.5

“…Kv1.5 N-terminus also has a functional interaction with the PDZ domain containing SAP97 protein, an expression regulator for Kv1.5 [7]. Moreover, the interacting protein KChIP2 that binds to the N-termini of Kv channels and modulates their surface density was recently shown to contribute to the formation of functional Kv1.5 [13].…”

Voltage-Regulated Potassium Channels

“…31 In contrast, KChIP coexpression does not affect the properties or the densities of Kv1.4-or Kv2.1-encoded K + currents, consistent with the suggestion that the modulatory effects of the KChIPs are specific for Kv4 α-subunit-encoded Kv channels. 31 More recent studies, however, suggest that the KChIPs modulate the functional cell surface expression of Kv1.5-encoded Kv channels, 38 as well as myocardial Cav channels. 39 In addition, although KChIP binding to Kv4 α-subunits is not Ca 2+ dependent, mutations in EF hand domains 2, 3, and 4 eliminate the modulatory effects of KChIP1 on Kv4-and Kv1.5-encoded Kv currents, 31,38 suggesting a role for voltage-dependent Ca 2+ entry and intracellular Ca 2+ levels in the regulation of functional cardiac (Kv4-encoded) I to,f channels, as has been demonstrated for neuronal Kv4-encoded channels.…”