Gβγ interacts with mTOR and promotes its activation.
Diverse G protein-coupled receptors depend on Gβγ heterodimers to promote cell polarization and survival via direct activation of PI3Kγ and potentially other effectors. These events involve full activation of AKT via its phosphorylation at Ser473, suggesting that mTORC2, the kinase that phosphorylates AKT at Ser473, is activated downstream of Gβγ. Thus, we tested the hypothesis that Gβγ directly contributes to mTOR signaling. Here, we demonstrate that endogenous mTOR interacts with Gβγ. Cell stimulation with serum modulates Gβγ interaction with mTOR. The carboxyl terminal region of mTOR, expressed as a GST-fusion protein, including the serine/threonine kinase domain, binds Gβγ heterodimers containing different Gβ subunits, except Gβ4. Both, mTORC1 and mTORC2 complexes interact with Gβ₁γ₂ which promotes phosphorylation of their respective substrates, p70S6K and AKT. In addition, chronic treatment with rapamycin, a condition known to interfere with assembly of mTORC2, reduces the interaction between Gβγ and mTOR and the phosphorylation of AKT; whereas overexpression of Gαi interfered with the effect of Gβγ as promoter of p70S6K and AKT phosphorylation. Altogether, our results suggest that Gβγ positively regulates mTOR signaling via direct interactions and provide further support to emerging strategies based on the therapeutical potential of inhibiting different Gβγ signaling interfaces.
Department of Pharmacology, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional (CINVESTAV-IPN), Apartado postal 14-740, México, D.F. 07360, Mexico.
Evelyn
E
Robles-Molina
Department of Cell Biology, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional (CINVESTAV-IPN), Apartado postal 14-740, México, D.F. 07360, Mexico.
Misael
M
Dionisio-Vicuña
Department of Pharmacology, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional (CINVESTAV-IPN), Apartado postal 14-740, México, D.F. 07360, Mexico.
María Luisa
ML
Guzmán-Hernández
Department of Cell Biology, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional (CINVESTAV-IPN), Apartado postal 14-740, México, D.F. 07360, Mexico.
Guadalupe
G
Reyes-Cruz
Department of Pharmacology, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional (CINVESTAV-IPN), Apartado postal 14-740, México, D.F. 07360, Mexico. Electronic address: jvazquez@cinvestav.mx.
José
J
Vázquez-Prado
D015153:Blotting, Western; D004789:Enzyme Activation / Q000187:drug effects; D044387:GTP-Binding Protein beta Subunits / Q000235:genetics / Q000378:metabolism*; D044388:GTP-Binding Protein gamma Subunits / Q000235:genetics / Q000378:metabolism*; D057809:HEK293 Cells; D006801:Humans; D047468:Immunoprecipitation; D000076222:Mechanistic Target of Rapamycin Complex 1; D000076225:Mechanistic Target of Rapamycin Complex 2; D046912:Multiprotein Complexes / Q000235:genetics / Q000378:metabolism; D010766:Phosphorylation / Q000187:drug effects; D011485:Protein Binding / Q000187:drug effects; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism; D038762:Ribosomal Protein S6 Kinases, 70-kDa / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects; D020123:Sirolimus / Q000494:pharmacology; D058570:TOR Serine-Threonine Kinases / Q000235:genetics / Q000378:metabolism*; D020798:Two-Hybrid System Techniques
D044387:GTP-Binding Protein beta Subunits; D044388:GTP-Binding Protein gamma Subunits; D046912:Multiprotein Complexes; C546842:MTOR protein, human; D000076222:Mechanistic Target of Rapamycin Complex 1; D000076225:Mechanistic Target of Rapamycin Complex 2; D051057:Proto-Oncogene Proteins c-akt; D038762:Ribosomal Protein S6 Kinases, 70-kDa; D058570:TOR Serine-Threonine Kinases; D020123:Sirolimus
AKT; Cell signaling; G-protein; G-protein coupled receptor; Gβγ; Raptor; Rictor; mTOR