N linked glycosylation of Kv1.2 voltage gated potassium channel facilitates cell surface expression and enhances the stability of internalized channels
Kv1.2 and related voltage gated potassium channels have a highly conserved N linked glycosylation site in the first extracellular loop, with complex glycosylation in COS 7 cells similar to endogenous Kv1.2 glycosylation in hippocampal neurons. COS 7 cells expressing Kv1.2 show a crucial role of this N linked glycosylation in the forward trafficking of Kv1.2 to the cell membrane. Although both wild type and non glycosylated mutant Kv1.2 channels that have reached the cell membrane are internalized at a comparable rate, mutant channels are degraded at a faster rate. Treatment of wild type Kv1.2 channels on the cell surface with glycosidase to remove sialic acids also results in the faster degradation of internalized channels. Glycosylation of Kv1.2 is important with respect to facilitating trafficking to the cell membrane and enhancing the stability of channels that have reached the cell membrane.
The Journal of physiology