Scavenging of 14-3-3 proteins reveals their involvement in the cell-surface transport of ATP-sensitive K+ channels
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Scavenging of 14-3-3 proteins reveals their involvement in the cell-surface transport of ATP-sensitive K+ channels. / Heusser, Katja; Yuan, Hebao; Neagoe, Ioana; Tarasov, Andrei I; Ashcroft, Frances M; Schwappach, Blanche.
In: J CELL SCI, Vol. 119, No. Pt 20, 15.10.2006, p. 4353-63.Research output: SCORING: Contribution to journal › SCORING: Journal article › Research › peer-review
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TY - JOUR
T1 - Scavenging of 14-3-3 proteins reveals their involvement in the cell-surface transport of ATP-sensitive K+ channels
AU - Heusser, Katja
AU - Yuan, Hebao
AU - Neagoe, Ioana
AU - Tarasov, Andrei I
AU - Ashcroft, Frances M
AU - Schwappach, Blanche
PY - 2006/10/15
Y1 - 2006/10/15
N2 - Arginine (Arg)-based endoplasmic reticulum (ER)-localization signals are involved in the quality control of different heteromultimeric membrane protein complexes. ATP-sensitive potassium (KATP) channels are unique because each subunit in the heterooctamer contains an Arg-based ER-localization signal. We have dissected the inactivation events that override the ER-localization activity of the eight peptide-sorting motifs. Employing a 14-3-3-scavenger construct to lower the availability of 14-3-3 proteins, we found that 14-3-3 proteins promote the cell-surface expression of heterologously expressed and native KATP channels. 14-3-3 proteins were detected in physical association with KATP channels in a pancreatic beta-cell line. Our results suggest that the Arg-based signal present in Kir6.2 is sterically masked by the SUR1 subunit. By contrast, 14-3-3 proteins functionally antagonized the Arg-based signal present in SUR1. The last ten amino acids were required for efficient 14-3-3 recruitment to multimeric forms of the Kir6.2 C-terminus. Channels containing a pore-forming subunit lacking these residues reached the cell surface inefficiently but were functionally indistinguishable from channels formed by the full-length subunits. In conclusion, 14-3-3 proteins promote the cell-surface transport of correctly assembled complexes but do not regulate the activity of KATP channels at the cell surface.
AB - Arginine (Arg)-based endoplasmic reticulum (ER)-localization signals are involved in the quality control of different heteromultimeric membrane protein complexes. ATP-sensitive potassium (KATP) channels are unique because each subunit in the heterooctamer contains an Arg-based ER-localization signal. We have dissected the inactivation events that override the ER-localization activity of the eight peptide-sorting motifs. Employing a 14-3-3-scavenger construct to lower the availability of 14-3-3 proteins, we found that 14-3-3 proteins promote the cell-surface expression of heterologously expressed and native KATP channels. 14-3-3 proteins were detected in physical association with KATP channels in a pancreatic beta-cell line. Our results suggest that the Arg-based signal present in Kir6.2 is sterically masked by the SUR1 subunit. By contrast, 14-3-3 proteins functionally antagonized the Arg-based signal present in SUR1. The last ten amino acids were required for efficient 14-3-3 recruitment to multimeric forms of the Kir6.2 C-terminus. Channels containing a pore-forming subunit lacking these residues reached the cell surface inefficiently but were functionally indistinguishable from channels formed by the full-length subunits. In conclusion, 14-3-3 proteins promote the cell-surface transport of correctly assembled complexes but do not regulate the activity of KATP channels at the cell surface.
KW - 14-3-3 Proteins/chemistry
KW - Adenosine Triphosphate/pharmacology
KW - Amino Acid Sequence
KW - Animals
KW - Arginine/metabolism
KW - Blotting, Western
KW - COS Cells
KW - Cell Line, Tumor
KW - Cell Membrane/metabolism
KW - Chlorocebus aethiops
KW - Dose-Response Relationship, Drug
KW - Female
KW - Gene Expression/genetics
KW - Membrane Potentials/drug effects
KW - Membrane Proteins/genetics
KW - Models, Biological
KW - Molecular Sequence Data
KW - Oocytes/drug effects
KW - Potassium Channels, Inwardly Rectifying/genetics
KW - Protein Binding
KW - Protein Transport/physiology
KW - Rats
KW - Recombinant Fusion Proteins/genetics
KW - Signal Transduction/physiology
KW - Xenopus
U2 - 10.1242/jcs.03196
DO - 10.1242/jcs.03196
M3 - SCORING: Journal article
C2 - 17038548
VL - 119
SP - 4353
EP - 4363
JO - J CELL SCI
JF - J CELL SCI
SN - 0021-9533
IS - Pt 20
ER -