Referenced in: none

Automatically associated channels: Kv1.1 , Kv1.2 , Kv1.5 , Kv1.7

Title: The Kv1.2 potassium channel: the position of an N-glycan on the extracellular linkers affects its protein expression and function.

Authors: Jing Zhu, Esperanza Recio-Pinto, Torsten Hartwig, Will Sellers, Jingyi Yan, William B Thornhill

Journal, date & volume: Brain Res., 2009 Jan 28 , 1251, 16-29

PubMed link: http://www.ncbi.nlm.nih.gov/pubmed/19056359

Abstract
Voltage-gated potassium Kv1 channels have three extracellular linkers, the S1-S2, the S3-S4, and the S5-P. The S1-S2 is the only linker that has an N-glycan and it is at a conserved position on this linker on Kv1.1-Kv1.5 and Kv1.7 channels. We hypothesize that an N-glycan is found at only this position due to its effect on folding, trafficking, and/or function of these channels. To investigate this hypothesis, N-glycosylation sites were engineered at different positions on the extracellular linkers of Kv1.2 to determine the effects of N-glycans on channel surface protein expression and function. Our data suggest that for Kv1 channels, (1) placing an N-glycan at non-native positions on the S1-S2 linker decreased cell surface protein expression but the N-glycan still affected function similarly as if it were at its native position, (2) placing a non-native N-glycan on the S3-S4 linker significantly altered function, and (3) placing a non-native N-glycan on the S5-P linker disrupted both trafficking and function. We suggest that Kv1 channels have an N-glycan at a conserved position on only the S1-S2 linker to overcome the constraints for proper folding, trafficking, and function that appear to occur if the N-glycan is moved from this position.