KV1.5–KVβ1.3 Recycling Is PKC-Dependent

Abstract

KV1.5 channel function is modified by different regulatory subunits. KVβ1.3 subunits assemble with KV1.5 channels and induce a fast and incomplete inactivation. Inhibition of PKC abolishes the KVβ1.3-induced fast inactivation, decreases the amplitude of the current KV1.5–KVβ1.3 and modifies their pharmacology likely due to changes in the traffic of KV1.5–KVβ1.3 channels in a PKC-dependent manner. In order to analyze this hypothesis, HEK293 cells were transfected with KV1.5–KVβ1.3 channels, and currents were recorded by whole-cell configuration of the patch-clamp technique. The presence of KV1.5 in the membrane was analyzed by biotinylation techniques, live cell imaging and confocal microscopy approaches. PKC inhibition resulted in a decrease of 33 ± 7% of channels in the cell surface due to reduced recycling to the plasma membrane, as was confirmed by confocal microscopy. Live cell imaging indicated that PKC inhibition almost abolished the recycling of the KV1.5–KVβ1.3 channels, generating an accumulation of channels into the cytoplasm. All these results suggest that the trafficking regulation of KV1.5–KVβ1.3 channels is dependent on phosphorylation by PKC and, therefore, they could represent a clinically relevant issue, mainly in those diseases that exhibit modifications in PKC activity.

A novel loss-of-function mutation of the voltage-gated potassium channel Kv10.2 involved in epilepsy and autism

“…The amount of cDNA transfected was 4 μg for the channel and 2 μg for EBO and the ratio of DNA:Fugene was 1:3. After 48 h transfection, cells were removed from culture plates using TrypLE™ Express (Gibco), after exposing cells to polystyrene microspheres bound to anti-CD8 (Dynabeads M-450; Thermo Fisher Scientific, Waltham, MA, USA) [ 67 – 69 ].…”

The Phosphorylation of Kv1.3: A Modulatory Mechanism for a Multifunctional Ion Channel

“…Kvβ1 accentuates the inactivation of Kvα with respect to the current, playing an essential role in cardiac cells. Kvβ1.3 can be phosphorylated by either PKA or PKC [51,113,117,118]. PKA phosphorylation alleviates Kvβ1.3-dependent Kvα inactivation.…”

“…When PKC is inhibited, the electrophysiological properties and pharmacological effects that Kvβ1.3 exerts on the Kvα subunits are abrogated, restoring a Kvα-only activity pattern [118]. Moreover, the recycling of the channel and the subunit to the plasma membrane is impaired [117]. Overall, PKC plays a considerable role in the trafficking of Kvβ1.3 and the Kvα subunit to the plasma membrane, promoting rapid Kvβ1.3-induced inactivation of the channel [117,118].…”

“…Moreover, the recycling of the channel and the subunit to the plasma membrane is impaired [117]. Overall, PKC plays a considerable role in the trafficking of Kvβ1.3 and the Kvα subunit to the plasma membrane, promoting rapid Kvβ1.3-induced inactivation of the channel [117,118].…”