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Serine 474 phosphorylation is essential for maximal Akt2 kinase activity in adipocytes.
- Source :
-
The Journal of biological chemistry [J Biol Chem] 2019 Nov 08; Vol. 294 (45), pp. 16729-16739. Date of Electronic Publication: 2019 Sep 22. - Publication Year :
- 2019
-
Abstract
- The Ser/Thr protein kinase Akt regulates essential biological processes such as cell survival, growth, and metabolism. Upon growth factor stimulation, Akt is phosphorylated at Ser <superscript>474</superscript> ; however, how this phosphorylation contributes to Akt activation remains controversial. Previous studies, which induced loss of Ser <superscript>474</superscript> phosphorylation by ablating its upstream kinase mTORC2, have implicated Ser <superscript>474</superscript> phosphorylation as a driver of Akt substrate specificity. Here we directly studied the role of Akt2 Ser <superscript>474</superscript> phosphorylation in 3T3-L1 adipocytes by preventing Ser <superscript>474</superscript> phosphorylation without perturbing mTORC2 activity. This was achieved by utilizing a chemical genetics approach, where ectopically expressed S474A Akt2 was engineered with a W80A mutation to confer resistance to the Akt inhibitor MK2206, and thus allow its activation independent of endogenous Akt. We found that insulin-stimulated phosphorylation of four bona fide Akt substrates (TSC2, PRAS40, FOXO1/3a, and AS160) was reduced by ∼50% in the absence of Ser <superscript>474</superscript> phosphorylation. Accordingly, insulin-stimulated mTORC1 activation, protein synthesis, FOXO nuclear exclusion, GLUT4 translocation, and glucose uptake were attenuated upon loss of Ser <superscript>474</superscript> phosphorylation. We propose a model where Ser <superscript>474</superscript> phosphorylation is required for maximal Akt2 kinase activity in adipocytes.<br /> (© 2019 Kearney et al.)
- Subjects :
- 3T3-L1 Cells
Adipocytes cytology
Animals
Cell Nucleus metabolism
Forkhead Box Protein O1 metabolism
Glucose metabolism
Glucose Transporter Type 4 metabolism
Heterocyclic Compounds, 3-Ring pharmacology
Insulin pharmacology
Mechanistic Target of Rapamycin Complex 1 metabolism
Mechanistic Target of Rapamycin Complex 2 metabolism
Mice
Mutagenesis, Site-Directed
Phosphorylation drug effects
Protein Biosynthesis drug effects
Proto-Oncogene Proteins c-akt genetics
Tuberous Sclerosis Complex 2 Protein metabolism
Proto-Oncogene Proteins c-akt metabolism
Serine metabolism
Subjects
Details
- Language :
- English
- ISSN :
- 1083-351X
- Volume :
- 294
- Issue :
- 45
- Database :
- MEDLINE
- Journal :
- The Journal of biological chemistry
- Publication Type :
- Academic Journal
- Accession number :
- 31548312
- Full Text :
- https://doi.org/10.1074/jbc.RA119.010036