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Diabetes
Article
Data sources: UnpayWall
Diabetes
Article . 2014 . Peer-reviewed
Data sources: Crossref
HKU Scholars Hub
Article . 2014
Data sources: HKU Scholars Hub
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The Adaptor Protein APPL2 Inhibits Insulin-Stimulated Glucose Uptake by Interacting With TBC1D1 in Skeletal Muscle

Authors: Lam, KSL; Sweeney, G; Wu, D; Wang, Y; CHEN, B; Zhu, W; Cheng, KY; +2 Authors

The Adaptor Protein APPL2 Inhibits Insulin-Stimulated Glucose Uptake by Interacting With TBC1D1 in Skeletal Muscle

Abstract

Insulin stimulates glucose uptake by promoting the trafficking of GLUT4 to the plasma membrane in muscle cells, and impairment of this insulin action contributes to hyperglycemia in type 2 diabetes. The adaptor protein APPL1 potentiates insulin-stimulated Akt activation and downstream actions. However, the physiological functions of APPL2, a close homolog of APPL1, in regulating glucose metabolism remain elusive. We show that insulin-evoked plasma membrane recruitment of GLUT4 and glucose uptake are impaired by APPL2 overexpression but enhanced by APPL2 knockdown. Likewise, conditional deletion of APPL2 in skeletal muscles enhances insulin sensitivity, leading to an improvement in glucose tolerance. We identified the Rab-GTPase–activating protein TBC1D1 as an interacting partner of APPL2. Insulin stimulates TBC1D1 phosphorylation on serine 235, leading to enhanced interaction with the BAR domain of APPL2, which in turn suppresses insulin-evoked TBC1D1 phosphorylation on threonine 596 in cultured myotubes and skeletal muscle. Substitution of serine 235 with alanine diminishes APPL2-mediated inhibition on insulin-dependent TBC1D1 phosphorylation on threonine 596 and the suppressive effects of TBC1D1 on insulin-induced glucose uptake and GLUT4 translocation to the plasma membrane in cultured myotubes. Therefore, the APPL2–TBC1D1 interaction is a key step to fine tune insulin-stimulated glucose uptake by regulating the membrane recruitment of GLUT4 in skeletal muscle.

Related Organizations
Keywords

Mice, Knockout, Biological Transport, Mice, Transgenic, Mass Spectrometry, Cell Line, Mice, Glucose, Animals, Humans, Immunoprecipitation, Insulin, RNA Interference, Phosphorylation, Muscle, Skeletal, Adaptor Proteins, Signal Transducing

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citations
This is an alternative to the "Influence" indicator, which also reflects the overall/total impact of an article in the research community at large, based on the underlying citation network (diachronically).
BIP!Citations provided by BIP!
popularity
This indicator reflects the "current" impact/attention (the "hype") of an article in the research community at large, based on the underlying citation network.
BIP!Popularity provided by BIP!
influence
This indicator reflects the overall/total impact of an article in the research community at large, based on the underlying citation network (diachronically).
BIP!Influence provided by BIP!
impulse
This indicator reflects the initial momentum of an article directly after its publication, based on the underlying citation network.
BIP!Impulse provided by BIP!
29
Top 10%
Top 10%
Top 10%
bronze