The glycosylation of the extracellular loop of β2 subunits diversifies functional phenotypes of BK Channels

Zhi Gang Huang, Hao Wen Liu, Zhen Zhen Yan, Sheng Wang, Lu Yang Wang, Jiu Ping Ding

Research output: Contribution to journalArticleResearchpeer-review

3 Citations (Scopus)

Abstract

Large-conductance Ca2+- and voltage-activated potassium (MaxiK or BK) channels are composed of a pore-forming α subunit (Slo) and 4 types of auxiliary β subunits or just a pore-forming α subunit. Although multiple N-linked glycosylation sites in the extracellular loop of β subunits have been identified, very little is known about how glycosylation influences the structure and function of BK channels. Using a combination of site-directed mutagenesis, western blot and patch-clamp recordings, we demonstrated that 3 sites in the extracellular loop of β2 subunit are N-glycosylated (N-X-T/S at N88, N96 and N119). Glycosylation of these sites strongly and differentially regulate gating kinetics, outward rectification, toxin sensitivity and physical association between the α and β2 subunits. We constructed a model and used molecular dynamics (MD) to simulate how the glycosylation facilitates the association of α/β2 subunits and modulates the dimension of the extracellular cavum above the pore of the channel, ultimately to modify biophysical and pharmacological properties of BK channels. Our results suggest that N-glycosylation of β2 subunits plays crucial roles in imparting functional heterogeneity of BK channels, and is potentially involved in the pathological phenotypes of carbohydrate metabolic diseases.

Original languageEnglish
Pages (from-to)156-166
Number of pages11
JournalChannels
Volume11
Issue number2
DOIs
Publication statusPublished - 4 Mar 2017
Externally publishedYes

Keywords

  • association
  • BK channels
  • glycosylation
  • mSlo1
  • β2

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