Dual role of K ATP channel C-terminal motif in membrane targeting and metabolic regulation.
The coordinated sorting of ion channels to specific plasma membrane domains is necessary for excitable cell physiology. K(ATP) channels, assembled from pore-forming (Kir6.x) and regulatory sulfonylurea receptor subunits, are critical electrical transducers of the metabolic state of excitable tissues, including skeletal and smooth muscle, heart, brain, kidney, and pancreas. Here we show that the C-terminal domain of Kir6.2 contains a motif conferring membrane targeting in primary excitable cells. Kir6.2 lacking this motif displays aberrant channel targeting due to loss of association with the membrane adapter ankyrin-B (AnkB). Moreover, we demonstrate that this Kir6.2 C-terminal AnkB-binding motif (ABM) serves a dual role in K(ATP) channel trafficking and membrane metabolic regulation and dysfunction in these pathways results in human excitable cell disease. Thus, the K(ATP) channel ABM serves as a previously unrecognized bifunctional touch-point for grading K(ATP) channel gating and membrane targeting and may play a fundamental role in controlling excitable cell metabolic regulation.
Kline
Crystal F
CF
Department of Internal Medicine, Division of Cardiology, University of Iowa Carver College of Medicine, Iowa City, IA 52242, USA.
Kurata
Harley T
HT
Hund
Thomas J
TJ
Cunha
Shane R
SR
Koval
Olha M
OM
Wright
Patrick J
PJ
Christensen
Matthew
M
Anderson
Mark E
ME
Nichols
Colin G
CG
Mohler
Peter J
PJ
D020816:Amino Acid Motifs; D000818:Animals; D017487:Ankyrins / Q000235:genetics / Q000378:metabolism; D001665:Binding Sites; D002462:Cell Membrane / Q000378:metabolism*; D002478:Cells, Cultured; D005260:Female; D006801:Humans; D008297:Male; D051379:Mice; D024661:Potassium Channels, Inwardly Rectifying / Q000235:genetics / Q000378:metabolism*; D014162:Transfection; D000099161:Kcnj11 Channel
D017487:Ankyrins; D024661:Potassium Channels, Inwardly Rectifying; D000099161:Kcnj11 Channel; C498995:Ank2 protein, mouse