Human Gene MTOR (ENST00000361445.9) Description and Page Index

Comments and Description Text from UniProtKB


	ID: MTOR_HUMAN DESCRIPTION: RecName: Full=Serine/threonine-protein kinase mTOR; EC=2.7.11.1; AltName: Full=FK506-binding protein 12-rapamycin complex-associated protein 1; AltName: Full=FKBP12-rapamycin complex-associated protein; AltName: Full=Mammalian target of rapamycin; Short=mTOR; AltName: Full=Mechanistic target of rapamycin; AltName: Full=Rapamycin and FKBP12 target 1; AltName: Full=Rapamycin target protein 1; FUNCTION: Serine/threonine protein kinase which is a central regulator of cellular metabolism, growth and survival in response to hormones, growth factors, nutrients, energy and stress signals. Functions as part of 2 structurally and functionally distinct signaling complexes mTORC1 and mTORC2 (mTOR complex 1 and 2). Activated mTORC1 up-regulates protein synthesis by phosphorylating key regulators of mRNA translation and ribosome synthesis. This includes phosphorylation of EIF4EBP1 and release of its inhibition toward the elongation initiation factor 4E (eiF4E). Moreover, phosphorylates and activates RPS6KB1 and RPS6KB2 that promote protein synthesis by modulating the activity of their downstream targets including ribosomal protein S6, eukaryotic translation initiation factor EIF4B and the inhibitor of translation initiation PDCD4. Regulates ribosome synthesis by activating RNA polymerase III-dependent transcription through phosphorylation and inhibition of MAF1 a RNA polymerase III-repressor. In parallel to protein synthesis, also regulates lipid synthesis through SREBF1/SREBP1 and LPIN1. To maintain energy homeostasis mTORC1 may also regulate mitochondrial biogenesis through regulation of PPARGC1A. mTORC1 also negatively regulates autophagy through phosphorylation of ULK1. Under nutrient sufficiency, phosphorylates ULK1 at 'Ser-758', disrupting the interaction with AMPK and preventing activation of ULK1. Also prevents autophagy through phosphorylation of the autophagy inhibitor DAP. mTORC1 exerts a feedback control on upstream growth factor signaling that includes phosphorylation and activation of GRB10 a INSR-dependent signaling suppressor. Among other potential targets mTORC1 may phosphorylate CLIP1 and regulate microtubules. As part of the mTORC2 complex MTOR may regulate other cellular processes including survival and organization of the cytoskeleton. Plays a critical role in the phosphorylation at 'Ser-473' of AKT1, a pro- survival effector of phosphoinositide 3-kinase, facilitating its activation by PDK1. mTORC2 may regulate the actin cytoskeleton, through phosphorylation of PRKCA, PXN and activation of the Rho- type guanine nucleotide exchange factors RHOA and RAC1A or RAC1B. mTORC2 also regulates the phosphorylation of SGK1 at 'Ser-422'. CATALYTIC ACTIVITY: ATP + a protein = ADP + a phosphoprotein. ENZYME REGULATION: Activation of mTORC1 by growth factors such as insulin involves AKT1-mediated phosphorylation of TSC1-TSC2, which leads to the activation of the RHEB GTPase a potent activator of the protein kinase activity of mTORC1. Insulin-stimulated and amino acid-dependent phosphorylation at Ser-1261 promotes autophosphorylation and the activation of mTORC1. Activation by amino acids requires relocalization of the mTORC1 complex to lysosomes that is mediated by the Ragulator complex and the Rag GTPases RRAGA, RRAGB, RRAGC and RRAGD. On the other hand, low cellular energy levels can inhibit mTORC1 through activation of PRKAA1 while hypoxia inhibits mTORC1 through a REDD1-dependent mechanism which may also require PRKAA1. The kinase activity of MTOR within the mTORC1 complex is positively regulated by MLST8 and negatively regulated by DEPTOR and AKT1S1. MTOR phosphorylates RPTOR which in turn inhibits mTORC1. mTORC1 binds and is inhibited by the FKBP1A-rapamycin complex. mTORC2 is also activated by growth factors, but seems to be nutrient-insensitive. It may be regulated by RHEB but in an indirect manner through the PI3K signaling pathway. SUBUNIT: Part of the mammalian target of rapamycin complex 1 (mTORC1) which contains MTOR, MLST8, RPTOR, AKT1S1/PRAS40 and DEPTOR. Part of the mammalian target of rapamycin complex 2 (mTORC2) which contains MTOR, MLST8, PRR5, RICTOR, MAPKAP1 and DEPTOR. Interacts with PPAPDC3 and PML (By similarity). Interacts with PRR5 and RICTOR; the interaction is direct within the mTORC2 complex (By similarity). Interacts with UBQLN1 (By similarity). Interacts with TTI1 and TELO2 (By similarity). Interacts with CLIP1; phosphorylates and regulates CLIP1 (By similarity). INTERACTION: Q8TB45:DEPTOR; NbExp=5; IntAct=EBI-359260, EBI-2359040; Q13541:EIF4EBP1; NbExp=2; IntAct=EBI-359260, EBI-74090; Q9BVC4:MLST8; NbExp=4; IntAct=EBI-359260, EBI-1387471; Q8TCU6:PREX1; NbExp=11; IntAct=EBI-359260, EBI-1046542; Q6R327:RICTOR; NbExp=17; IntAct=EBI-359260, EBI-1387196; Q8N122:RPTOR; NbExp=12; IntAct=EBI-359260, EBI-1567928; Q96EB6:SIRT1; NbExp=2; IntAct=EBI-359260, EBI-1802965; SUBCELLULAR LOCATION: Endoplasmic reticulum membrane; Peripheral membrane protein; Cytoplasmic side. Golgi apparatus membrane; Peripheral membrane protein; Cytoplasmic side. Mitochondrion outer membrane; Peripheral membrane protein; Cytoplasmic side. Lysosome. Cytoplasm (By similarity). Nucleus, PML body (By similarity). Note=Shuttles between cytoplasm and nucleus. Accumulates in the nucleus in response to hypoxia (By similarity). Targeting to lysosomes depends on amino acid availability and RRAGA and RRAGB. TISSUE SPECIFICITY: Expressed in numerous tissues, with highest levels in testis. PTM: Phosphorylated. Autophosphorylates when part of mTORC1 or mTORC2. Phosphorylation at Ser-1261 promotes autophosphorylation. SIMILARITY: Belongs to the PI3/PI4-kinase family. SIMILARITY: Contains 1 FAT domain. SIMILARITY: Contains 1 FATC domain. SIMILARITY: Contains 7 HEAT repeats. SIMILARITY: Contains 1 PI3K/PI4K domain. SEQUENCE CAUTION: Sequence=AAC39933.1; Type=Frameshift; Positions=956, 999; Sequence=BAE06077.1; Type=Erroneous initiation; Note=Translation N-terminally shortened; WEB RESOURCE: Name=Atlas of Genetics and Cytogenetics in Oncology and Haematology; URL="http://atlasgeneticsoncology.org/Genes/FRAP1ID40639ch1p36.html"; WEB RESOURCE: Name=Wikipedia; Note=Mammalian target of rapamycin entry; URL="http://en.wikipedia.org/wiki/Mammalian_target_of_rapamycin"; WEB RESOURCE: Name=Target mTOR; Note=mTOR signaling pathway and mTOR inhibition resource; URL="http://www.targetmtor.com/index.jsp";