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Identification and characterization of site‐specific N‐glycosylation in the potassium channel Kv3.1b
Author(s) -
Vicente Paul Christian,
Kim Jin Young,
Ha JeongJu,
Song MinYoung,
Lee HyunKyung,
Kim DongHyun,
Choi JinSung,
Park KangSik
Publication year - 2018
Publication title -
journal of cellular physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.529
H-Index - 174
eISSN - 1097-4652
pISSN - 0021-9541
DOI - 10.1002/jcp.25915
Subject(s) - glycosylation , calnexin , glycan , asparagine , endoplasmic reticulum , chemistry , n linked glycosylation , glycoprotein , biochemistry , potassium channel , membrane protein , ion channel , biology , membrane , biophysics , calreticulin , amino acid , receptor
The potassium ion channel Kv3.1b is a member of a family of voltage‐gated ion channels that are glycosylated in their mature form. In the present study, we demonstrate the impact of N‐glycosylation at specific asparagine residues on the trafficking of the Kv3.1b protein. Large quantities of asparagine 229 (N229)‐glycosylated Kv3.1b reached the plasma membrane, whereas N220‐glycosylated and unglycosylated Kv3.1b were mainly retained in the endoplasmic reticulum (ER). These ER‐retained Kv3.1b proteins were susceptible to degradation, when co‐expressed with calnexin, whereas Kv3.1b pools located at the plasma membrane were resistant. Mass spectrometry analysis revealed a complex type Hex 3 HexNAc 4 Fuc 1 glycan as the major glycan component of the N229‐glycosylated Kv3.1b protein, as opposed to a high‐mannose type Man 8 GlcNAc 2 glycan for N220‐glycosylated Kv3.1b. Taken together, these results suggest that trafficking‐dependent roles of the Kv3.1b potassium channel are dependent on N229 site‐specific glycosylation and N‐glycan structure, and operate through a mechanism whereby specific N‐glycan structures regulate cell surface expression.