Rapid mitogenic regulation of the mTORC1 inhibitor, DEPTOR, by phosphatidic acid.
The mammalian target of rapamycin complex 1 (mTORC1) is regulated, in part, by the endogenous inhibitor DEPTOR. However, the mechanism of DEPTOR regulation with regard to rapid mTORC1 activation remains unknown. We report that DEPTOR is rapidly and temporarily dissociated from mTORC1 upon mitogenic stimulation, suggesting a mechanism underlying acute mTORC1 activation. This mitogen-stimulated DEPTOR dissociation is blocked by inhibition or depletion of the mTORC1 regulator, phospholipase D (PLD), and recapitulated with the addition of the PLD product phosphatidic acid (PA). Our mass spectrometry analysis has independently identified DEPTOR as an mTOR binding partner dissociated by PA. Interestingly, only PA species with unsaturated fatty acid chains, such as those produced by PLD, are capable of displacing DEPTOR and activating mTORC1, with high affinity for the FRB domain of mTOR. Our findings reveal a mechanism of mTOR regulation and provide a molecular explanation for the exquisite specificity of PA function.
Department of Cell and Developmental Biology, University of Illinois, Urbana-Champaign, Urbana, IL 61801, USA; Department of Molecular Medicine, Graduate School of Medicine, Gachon University, Incheon 406-840, Republic of Korea. Electronic address: msyoon@gachon.ac.kr.
Mee-Sup
MS
Yoon
Department of Cell and Developmental Biology, University of Illinois, Urbana-Champaign, Urbana, IL 61801, USA.
Christina L
CL
Rosenberger
Departments of Chemistry and Biochemistry, University of Illinois, Urbana-Champaign, Urbana, IL 61801, USA.
Cong
C
Wu
Department of Cell and Developmental Biology, University of Illinois, Urbana-Champaign, Urbana, IL 61801, USA.
Nga
N
Truong
Departments of Chemistry and Biochemistry, University of Illinois, Urbana-Champaign, Urbana, IL 61801, USA.
Jonathan V
JV
Sweedler
Department of Cell and Developmental Biology, University of Illinois, Urbana-Champaign, Urbana, IL 61801, USA. Electronic address: jiechen@illinois.edu.
Jie
J
Chen
D016475:3T3 Cells; D000818:Animals; D001667:Binding, Competitive / Q000187:drug effects; D015153:Blotting, Western; D002460:Cell Line; D003470:Culture Media / Q000494:pharmacology; D057809:HEK293 Cells; D006367:HeLa Cells; D006801:Humans; D007328:Insulin / Q000494:pharmacology; D047908:Intracellular Signaling Peptides and Proteins / Q000235:genetics / Q000378:metabolism*; D013058:Mass Spectrometry; D000076222:Mechanistic Target of Rapamycin Complex 1; D051379:Mice; D008934:Mitogens / Q000378:metabolism* / Q000494:pharmacology; D046912:Multiprotein Complexes / Q000235:genetics / Q000378:metabolism*; D010712:Phosphatidic Acids / Q000378:metabolism* / Q000494:pharmacology; D010739:Phospholipase D / Q000378:metabolism; D011485:Protein Binding / Q000187:drug effects; D034622:RNA Interference; D044967:Serum; D058570:TOR Serine-Threonine Kinases / Q000235:genetics / Q000378:metabolism*; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology
D003470:Culture Media; D007328:Insulin; D047908:Intracellular Signaling Peptides and Proteins; D008934:Mitogens; D046912:Multiprotein Complexes; D010712:Phosphatidic Acids; C556139:DEPTOR protein, human; C546842:MTOR protein, human; D000076222:Mechanistic Target of Rapamycin Complex 1; D058570:TOR Serine-Threonine Kinases; D010739:Phospholipase D; D013755:Tetradecanoylphorbol Acetate