Lanthionine synthetase C-like protein 2 (LanCL2) is a novel regulator of Akt.
The serine/threonine protein kinase Akt controls a wide range of biochemical and cellular processes under the modulation of a variety of regulators. In this study, we identify the lanthionine synthetase C-like 2 (LanCL2) protein as a positive regulator of Akt activation in human liver cells. LanCL2 knockdown dampens serum- and ... insulin-stimulated Akt phosphorylation, whereas LanCL2 overexpression enhances these processes. Neither insulin receptor phosphorylation nor the interaction between insulin receptor substrate and phosphatidylinositide 3-kinase (PI3K) is affected by LanCL2 knockdown. LanCL2 also does not function through PP2A, a phosphatase of Akt. Instead, LanCL2 directly interacts with Akt, with a preference for inactive Akt. Moreover, we show that LanCL2 also binds to the Akt kinase mTORC2, but not phosphoinositide-dependent kinase 1. Whereas LanCL2 is not required for the Akt-mTORC2 interaction, recombinant LanCL2 enhances Akt phosphorylation by target of rapamycin complex 2 (mTORC2) in vitro. Finally, consistent with a function of Akt in regulating cell survival, LanCL2 knockdown increases the rate of apoptosis, which is reversed by the expression of a constitutively active Akt. Taken together, our findings reveal LanCL2 as a novel regulator of Akt and suggest that LanCL2 facilitates optimal phosphorylation of Akt by mTORC2 via direct physical interactions with both the kinase and the substrate.
Mesh Terms:
Alanine, Apoptosis, Blotting, Western, Cell Line, Transformed, Cell Survival, HEK293 Cells, Hep G2 Cells, Humans, Mechanistic Target of Rapamycin Complex 2, Membrane Proteins, Microscopy, Fluorescence, Multiprotein Complexes, Nuclear Proteins, Phosphorylation, Protein Binding, Proto-Oncogene Proteins c-akt, RNA Interference, Sulfides, TOR Serine-Threonine Kinases
Alanine, Apoptosis, Blotting, Western, Cell Line, Transformed, Cell Survival, HEK293 Cells, Hep G2 Cells, Humans, Mechanistic Target of Rapamycin Complex 2, Membrane Proteins, Microscopy, Fluorescence, Multiprotein Complexes, Nuclear Proteins, Phosphorylation, Protein Binding, Proto-Oncogene Proteins c-akt, RNA Interference, Sulfides, TOR Serine-Threonine Kinases
Mol. Biol. Cell
Date: Dec. 01, 2014
PubMed ID: 25273559
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