Pharmacological correction of trafficking defects in ATP-sensitive potassium channels caused by sulfonylurea receptor 1 mutations

Gregory M. Martin, Emily A. Rex, Prasanna Devaraneni, Jerod S. Denton, Kara E. Boodhansingh, Diva D. DeLeon, Charles A. Stanley, Show-Ling Shyng

Research output: Contribution to journalArticle

13 Citations (Scopus)

Abstract

ATP-sensitive potassium (KATP) channels play a key role in mediating glucose-stimulated insulin secretion by coupling metabolic signals to β-cell membrane potential. Loss of KATP channel function due to mutations in ABCC8 or KCNJ11, genes encoding the sulfonylurea receptor 1 (SUR1) or the inwardly rectifying potassium channel Kir6.2, respectively, results in congenital hyperinsulinism. Many SUR1 mutations prevent trafficking of channel proteins from the endoplasmic reticulum to the cell surface. Channel inhibitors, including sulfonylureas and carbamazepine, have been shown to correct channel trafficking defects. In the present study, we identified 13 novel SUR1 mutations that cause channel trafficking defects, the majority of which are amenable to pharmacological rescue by glibenclamide and carbamazepine. By contrast, none of the mutant channels were rescued by KATP channel openers. Cross-linking experiments showed that KATP channel inhibitors promoted interactions between the N terminus of Kir6.2 and SUR1, whereas channel openers did not, suggesting the inhibitors enhance intersubunit interactions to overcome channel biogenesis and trafficking defects. Functional studies of rescued mutant channels indicate that most mutants rescued to the cell surface exhibited WT-like sensitivity to ATP, MgADP, and diazoxide. In intact cells, recovery of channel function upon trafficking rescue by reversible sulfonylureas or carbamazepine was facilitated by the KATP channel opener diazoxide. Our study expands the list of KATP channel trafficking mutations whose function can be recovered by pharmacological ligands and provides further insight into the structural mechanism by which channel inhibitors correct channel biogenesis and trafficking defects.

Original languageEnglish (US)
Pages (from-to)21971-21983
Number of pages13
JournalJournal of Biological Chemistry
Volume291
Issue number42
DOIs
StatePublished - Oct 14 2016

Fingerprint

Sulfonylurea Receptors
KATP Channels
Pharmacology
Defects
Mutation
Carbamazepine
Diazoxide
Adenosine Triphosphate
Inwardly Rectifying Potassium Channel
Congenital Hyperinsulinism
Gene encoding
Glyburide
Cell membranes
Recovery of Function
Adenosine Diphosphate
Protein Transport
Potassium
Endoplasmic Reticulum
Membrane Potentials
Insulin

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology

Cite this

Pharmacological correction of trafficking defects in ATP-sensitive potassium channels caused by sulfonylurea receptor 1 mutations. / Martin, Gregory M.; Rex, Emily A.; Devaraneni, Prasanna; Denton, Jerod S.; Boodhansingh, Kara E.; DeLeon, Diva D.; Stanley, Charles A.; Shyng, Show-Ling.

In: Journal of Biological Chemistry, Vol. 291, No. 42, 14.10.2016, p. 21971-21983.

Research output: Contribution to journalArticle

Martin, Gregory M. ; Rex, Emily A. ; Devaraneni, Prasanna ; Denton, Jerod S. ; Boodhansingh, Kara E. ; DeLeon, Diva D. ; Stanley, Charles A. ; Shyng, Show-Ling. / Pharmacological correction of trafficking defects in ATP-sensitive potassium channels caused by sulfonylurea receptor 1 mutations. In: Journal of Biological Chemistry. 2016 ; Vol. 291, No. 42. pp. 21971-21983.
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