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A Role of the Sulfonylurea Receptor 1 in Endocytic Trafficking of ATP‐Sensitive Potassium Channels
Author(s) -
Bruederle Cathrin E.,
Gay Joel,
Shyng ShowLing
Publication year - 2011
Publication title -
traffic
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.677
H-Index - 130
eISSN - 1600-0854
pISSN - 1398-9219
DOI - 10.1111/j.1600-0854.2011.01227.x
Subject(s) - sulfonylurea receptor , endocytic cycle , endocytosis , potassium channel , microbiology and biotechnology , biology , exocytosis , kir6.2 , protein subunit , receptor , secretion , biochemistry , biophysics , gene
The ATP‐sensitive potassium (K ATP ) channel consisting of sulfonylurea receptor 1 (SUR1) and inward‐rectifier potassium channel 6.2 (Kir6.2) has a well‐established role in insulin secretion. Mutations in either subunit can lead to disease due to aberrant channel gating, altered channel density at the cell surface or a combination of both. Endocytic trafficking of channels at the plasma membrane is one way to influence surface channel numbers. It has been previously reported that channel endocytosis is dependent on a tyrosine‐based motif in Kir6.2, while SUR1 alone is unable to internalize. In this study, we followed endocytic trafficking of surface channels in real time by live‐cell imaging of channel subunits tagged with an extracellular minimal α‐bungarotoxin‐binding peptide labeled with a fluorescent dye. We show that SUR1 undergoes endocytosis independent of Kir6.2. Moreover, mutations in the putative endocytosis motif of Kir6.2, Y330C, Y330A and F333I are unable to prevent channel endocytosis. These findings challenge the notion that Kir6.2 bears the sole endocytic signal for K ATP channels and support a role of SUR1 in this trafficking process.