The degree of N-glycosylation affects the trafficking and cell surface expression levels of Kv1.4 potassium channels.
J Membr Biol
; 248(2): 187-96, 2015 Apr.
Article
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| MEDLINE
| ID: mdl-25416425
ABSTRACT
Kv1.4 potassium channels are heavily glycosylated proteins involved in shaping action potentials and in neuronal excitability and plasticity. Kv1.4 N354Q, without an N-glycan, exhibited decreased protein stability and trafficking to the cell surface (Watanabe et al. in J Biol Chem 2798879-8885, 2004). Here we investigated whether the composition of the N-glycan affected Kv1.4 cell surface expression. Kv1.4 proteins carrying N-glycans with different compositions were generated by adding glycosidase inhibitors or using N-glycosylation-deficient mutant cell lines. We found that oligomannose-type, hybrid-type, or incomplete complex-type N-glycans had a negative effect on surface protein expression of Kv1.4 compared with complex-type N-glycans. The decrease in surface protein level of Kv1.4 was mainly due to a reduction in total protein level, induced by altered N-glycan composition. Kv1.4 in CSTP-treated cells carried a unique oligomannose-type N-glycan that contains three glucose residues. This N-glycan had the most negative effect on cell surface expression of Kv1.4. It decreased Kv1.4 surface protein level by a combined mechanism of reducing total protein level and increasing ER-retention. Our data suggest that composition of the N-glycan plays an important role in protein stability and trafficking, and a sialylated complex-type N-glycan promoted high cell surface expression of Kv1.4.
Texto completo:
1
Bases de datos:
MEDLINE
Asunto principal:
Membrana Celular
/
Canal de Potasio Kv1.4
Límite:
Animals
Idioma:
En
Revista:
J Membr Biol
Año:
2015
Tipo del documento:
Article
País de afiliación:
Estados Unidos