Identification and characterization of site-specific N-glycosylation in the potassium channel Kv3.1b.
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 Hex3HexNAc4Fuc1glycan as the major glycan component of the N229-glycosylated Kv3.1b protein, as opposed to a high-mannose type Man8GlcNAc2glycan 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.
Department of Physiology, School of Medicine, Kyung Hee University, Seoul, South Korea.
Paul Christian
PC
Vicente
Biomedical Omics Group, Korea Basic Science Institute, Cheongju-si, Chungcheongbuk-do, South Korea.
Jin Young
JY
Kim
Department of Physiology, School of Medicine, Kyung Hee University, Seoul, South Korea.
Jeong-Ju
JJ
Ha
Department of Physiology, School of Medicine, Kyung Hee University, Seoul, South Korea.|Biomedical Omics Group, Korea Basic Science Institute, Cheongju-si, Chungcheongbuk-do, South Korea.
Min-Young
MY
Song
Biomedical Omics Group, Korea Basic Science Institute, Cheongju-si, Chungcheongbuk-do, South Korea.|Graduate School of Analytical Science and Technology, Chungnam National University, Daejeon, South Korea.
Hyun-Kyung
HK
Lee
College of Pharmacy, Catholic University of Korea, Bucheon, Gyeonggi-Do, South Korea.
Dong-Hyun
DH
Kim
College of Pharmacy, Catholic University of Korea, Bucheon, Gyeonggi-Do, South Korea.
Jin-Sung
JS
Choi
Department of Physiology, School of Medicine, Kyung Hee University, Seoul, South Korea.
Kang-Sik
http://orcid.org/0000-0002-4709-6287
KS
Park
D000818:Animals; D001216:Asparagine; D019556:COS Cells; D002462:Cell Membrane / Q000378:metabolism; D002522:Chlorocebus aethiops; D004721:Endoplasmic Reticulum / Q000378:metabolism; D006031:Glycosylation; D009154:Mutation; D009419:Nerve Tissue Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D011487:Protein Conformation; D011499:Protein Processing, Post-Translational; D021381:Protein Transport; D051381:Rats; D051670:Shaw Potassium Channels / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D013329:Structure-Activity Relationship; D014162:Transfection
C098254:Kcnc1 protein, rat; D009419:Nerve Tissue Proteins; D051670:Shaw Potassium Channels; D001216:Asparagine
Kv3.1b; N-glycan structure; N-glycosylation; mass spectrometry; potassium channel; surface expression