Global phosphoproteomics identifies a major role for AKT and 14-3-3 in regulating EDC3.
Insulin plays an essential role in metabolic homeostasis in mammals, and many of the underlying biochemical pathways are regulated via the canonical phosphatidylinositol 3-kinase/AKT pathway. To identify novel metabolic actions of insulin, we conducted a quantitative proteomics analysis of insulin-regulated 14-3-3-binding proteins in muscle cells. These studies revealed a novel role for insulin in the post-transcriptional regulation of mRNA expression. EDC3, a component of the mRNA decay and translation repression pathway associated with mRNA processing bodies, was shown to be phosphorylated by AKT downstream of insulin signaling. The major insulin-regulated site was mapped to Ser-161, and phosphorylation at this site led to increased 14-3-3 binding. Functional studies indicated that induction of 14-3-3 binding to EDC3 causes morphological changes in processing body structures, inhibition of microRNA-mediated mRNA post-transcriptional regulation, and alterations in the protein- protein interactions of EDC3. These data highlight an important new arm of the insulin signaling cascade in the regulation of mRNA utilization.
Larance
Mark
M
Diabetes and Obesity Program, Garvan Institute of Medical Research, Sydney, Australia. m.larance@dundee.ac.uk
Rowland
Alexander F
AF
Hoehn
Kyle L
KL
Humphreys
David T
DT
Preiss
Thomas
T
Guilhaus
Michael
M
James
David E
DE
D048948:14-3-3 Proteins / Q000302:isolation & purification / Q000378:metabolism / Q000502:physiology*; D000818:Animals; D001665:Binding Sites; D016466:CHO Cells; D002478:Cells, Cultured; D006224:Cricetinae; D003412:Cricetulus; D005786:Gene Expression Regulation; D006801:Humans; D051379:Mice; D035683:MicroRNAs / Q000494:pharmacology / Q000502:physiology; D041681:NIH 3T3 Cells; D051058:Oncogene Protein v-akt / Q000302:isolation & purification / Q000378:metabolism / Q000502:physiology*; D010750:Phosphoproteins / Q000032:analysis*; D010766:Phosphorylation; D025941:Protein Interaction Mapping; D040901:Proteomics / Q000379:methods*; D034622:RNA Interference; D020871:RNA Stability / Q000502:physiology; D017411:Ribonucleoproteins, Small Nuclear / Q000378:metabolism
D048948:14-3-3 Proteins; C551442:EDC3 protein, mouse; D035683:MicroRNAs; D010750:Phosphoproteins; D017411:Ribonucleoproteins, Small Nuclear; D051058:Oncogene Protein v-akt