TY - JOUR
T1 - Sulfonylureas Correct Trafficking Defects of ATP-sensitive Potassium Channels Caused by Mutations in the Sulfonylurea Receptor
AU - Yan, Feifei
AU - Lin, Chia Wei
AU - Weisiger, Elizabeth
AU - Cartier, Etienne A.
AU - Taschenberger, Grit
AU - Shyng, Show Ling
PY - 2004/3/19
Y1 - 2004/3/19
N2 - The pancreatic ATP-sensitive potassium (KATP) channel, a complex of four sulfonylurea receptor 1 (SUR1) and four potassium channel Kir6. 2 subunits, regulates insulin secretion by linking metabolic changes to β-cell membrane potential. Sulfonylureas inhibit KATP channel activities by binding to SUR1 and are widely used to treat type II diabetes. We report here that sulfonylureas also function as chemical chaperones to rescue KATP channel trafficking defects caused by two SUR1 mutations, A116P and V187D, identified in patients with congenital hyperinsulinism. Sulfonylureas markedly increased cell surface expression of the A116P and V187D mutants by stabilizing the mutant SUR1 proteins and promoting their maturation. By contrast, diazoxide, a potassium channel opener that also binds SUR1, had no effect on surface expression of either mutant. Importantly, both mutant channels rescued to the cell surface have normal ATP, MgADP, and diazoxide sensitivities, demonstrating that SUR1 harboring either the A116P or the V187D mutation is capable of associating with Kir6.2 to form functional K ATP channels. Thus, sulfonylureas may be used to treat congenital hyperinsulinism caused by certain KATP channel trafficking mutations.
AB - The pancreatic ATP-sensitive potassium (KATP) channel, a complex of four sulfonylurea receptor 1 (SUR1) and four potassium channel Kir6. 2 subunits, regulates insulin secretion by linking metabolic changes to β-cell membrane potential. Sulfonylureas inhibit KATP channel activities by binding to SUR1 and are widely used to treat type II diabetes. We report here that sulfonylureas also function as chemical chaperones to rescue KATP channel trafficking defects caused by two SUR1 mutations, A116P and V187D, identified in patients with congenital hyperinsulinism. Sulfonylureas markedly increased cell surface expression of the A116P and V187D mutants by stabilizing the mutant SUR1 proteins and promoting their maturation. By contrast, diazoxide, a potassium channel opener that also binds SUR1, had no effect on surface expression of either mutant. Importantly, both mutant channels rescued to the cell surface have normal ATP, MgADP, and diazoxide sensitivities, demonstrating that SUR1 harboring either the A116P or the V187D mutation is capable of associating with Kir6.2 to form functional K ATP channels. Thus, sulfonylureas may be used to treat congenital hyperinsulinism caused by certain KATP channel trafficking mutations.
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U2 - 10.1074/jbc.M312810200
DO - 10.1074/jbc.M312810200
M3 - Article
C2 - 14707124
AN - SCOPUS:1642565240
SN - 0021-9258
VL - 279
SP - 11096
EP - 11105
JO - Journal of Biological Chemistry
JF - Journal of Biological Chemistry
IS - 12
ER -