K1.5-Kβ1.3 Recycling Is PKC-Dependent.

K1.5 channel function is modified by different regulatory subunits. Kβ1.3 subunits assemble with K1.5 channels and induce a fast and incomplete inactivation. Inhibition of PKC abolishes the Kβ1.3-induced fast inactivation, decreases the amplitude of the current K1.5-Kβ1.3 and modifies their pharmacology likely due to changes in the traffic of K1.5-Kβ1.3 channels in a PKC-dependent manner. In order to analyze this hypothesis, HEK293 cells were transfected with K1.5-Kβ1.3 channels, and currents were recorded by whole-cell configuration of the patch-clamp technique. The presence of K1.5 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 K1.5-Kβ1.3 channels, generating an accumulation of channels into the cytoplasm. All these results suggest that the trafficking regulation of K1.5-Kβ1.3 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.