PMID- 22544753 OWN - NLM STAT- MEDLINE DCOM- 20120824 LR - 20211203 IS - 1083-351X (Electronic) IS - 0021-9258 (Print) IS - 0021-9258 (Linking) VI - 287 IP - 25 DP - 2012 Jun 15 TI - Ubiquitin-specific peptidase 9, X-linked (USP9X) modulates activity of mammalian target of rapamycin (mTOR). PG - 21164-75 LID - 10.1074/jbc.M111.328021 [doi] AB - The mammalian target of rapamycin (mTOR) is an atypical serine/threonine kinase that responds to extracellular environment to regulate a number of cellular processes. These include cell growth, proliferation, and differentiation. Although both kinase-dependent and -independent functions of mTOR are known to be critical modulators of muscle cell differentiation and regeneration, the signaling mechanisms regulating mTOR activity during differentiation are still unclear. In this study we identify a novel mTOR interacting protein, the ubiquitin-specific protease USP9X, which acts as a negative regulator of mTOR activity and muscle differentiation. USP9X can co-immunoprecipitate mTOR with both Raptor and Rictor, components of mTOR complexes 1 and 2 (mTORC1 and -2), respectively, suggesting that it is present in both mTOR complexes. Knockdown of USP9X leads to increased mTORC1 activity in response to growth factor stimulation. Interestingly, upon initiation of differentiation of C2C12 mouse skeletal myoblasts, knockdown of USP9X increases mTORC2 activity. This increase in mTORC2 activity is accompanied by accelerated differentiation of myoblasts into myotubes. Taken together, our data describe the identification of the deubiquitinase USP9X as a novel mTORC1 and -2 binding partner that negatively regulates mTOR activity and skeletal muscle differentiation. FAU - Agrawal, Pooja AU - Agrawal P AD - Buck Institute for Research on Aging, Novato, California 94945, USA. FAU - Chen, Yu-Ting AU - Chen YT FAU - Schilling, Birgit AU - Schilling B FAU - Gibson, Bradford W AU - Gibson BW FAU - Hughes, Robert E AU - Hughes RE LA - eng GR - PL1 AG032118/AG/NIA NIH HHS/United States GR - RL1 GM084432/GM/NIGMS NIH HHS/United States GR - S10 RR024615/RR/NCRR NIH HHS/United States GR - TL1 AG032116/AG/NIA NIH HHS/United States PT - Journal Article PT - Research Support, N.I.H., Extramural DEP - 20120427 PL - United States TA - J Biol Chem JT - The Journal of biological chemistry JID - 2985121R RN - 0 (Adaptor Proteins, Signal Transducing) RN - 0 (CRTC2 protein, human) RN - 0 (Carrier Proteins) RN - 0 (Crtc2 protein, mouse) RN - 0 (Multiprotein Complexes) RN - 0 (Muscle Proteins) RN - 0 (Proteins) RN - 0 (RICTOR protein, human) RN - 0 (RPTOR protein, human) RN - 0 (Rapamycin-Insensitive Companion of mTOR Protein) RN - 0 (Regulatory-Associated Protein of mTOR) RN - 0 (Rptor protein, mouse) RN - 0 (Trans-Activators) RN - 0 (Transcription Factors) RN - 0 (USP9X protein, human) RN - 0 (rictor protein, mouse) RN - EC 2.7.1.1 (MTOR protein, human) RN - EC 2.7.1.1 (mTOR protein, mouse) RN - EC 2.7.11.1 (Mechanistic Target of Rapamycin Complex 1) RN - EC 2.7.11.1 (TOR Serine-Threonine Kinases) RN - EC 3.4.- (Endopeptidases) RN - EC 3.4.19.12 (Ubiquitin Thiolesterase) RN - EC 3.4.19.12 (Usp9x protein, mouse) SB - IM MH - Adaptor Proteins, Signal Transducing/genetics/metabolism MH - Animals MH - Carrier Proteins/genetics/metabolism MH - Cell Differentiation/*physiology MH - Endopeptidases/genetics/*metabolism MH - HEK293 Cells MH - Humans MH - Mechanistic Target of Rapamycin Complex 1 MH - Mice MH - Multiprotein Complexes MH - Muscle Development/*physiology MH - Muscle Proteins/genetics/*metabolism MH - Myoblasts, Skeletal/cytology/*metabolism MH - Proteins/genetics/metabolism MH - Rapamycin-Insensitive Companion of mTOR Protein MH - Regulatory-Associated Protein of mTOR MH - TOR Serine-Threonine Kinases/genetics/*metabolism MH - Trans-Activators/genetics/metabolism MH - Transcription Factors/genetics/metabolism MH - Ubiquitin Thiolesterase/genetics/*metabolism PMC - PMC3375539 EDAT- 2012/05/01 06:00 MHDA- 2012/08/25 06:00 PMCR- 2013/06/15 CRDT- 2012/05/01 06:00 PHST- 2012/05/01 06:00 [entrez] PHST- 2012/05/01 06:00 [pubmed] PHST- 2012/08/25 06:00 [medline] PHST- 2013/06/15 00:00 [pmc-release] AID - S0021-9258(20)49809-6 [pii] AID - M111.328021 [pii] AID - 10.1074/jbc.M111.328021 [doi] PST - ppublish SO - J Biol Chem. 2012 Jun 15;287(25):21164-75. doi: 10.1074/jbc.M111.328021. Epub 2012 Apr 27.