View source for 5wbu


==Crystal structure of mTOR(deltaN)-mLST8-PRAS40(alpha-helix & beta-strand) complex==
<StructureSection load='5wbu' size='340' side='right'caption='[[5wbu]], [[Resolution|resolution]] 3.42&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[5wbu]] is a 8 chain structure with sequence from [https://en.wikipedia.org/wiki/Homo_sapiens Homo sapiens]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=5WBU OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=5WBU FirstGlance]. <br>
</td></tr><tr id='method'><td class="sblockLbl"><b>[[Empirical_models|Method:]]</b></td><td class="sblockDat" id="methodDat">X-ray diffraction, [[Resolution|Resolution]] 3.42&#8491;</td></tr>
<tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[https://proteopedia.org/fgij/fg.htm?mol=5wbu FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=5wbu OCA], [https://pdbe.org/5wbu PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=5wbu RCSB], [https://www.ebi.ac.uk/pdbsum/5wbu PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=5wbu ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/MTOR_HUMAN MTOR_HUMAN] 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'.<ref>PMID:12150925</ref> <ref>PMID:12150926</ref> <ref>PMID:12231510</ref> <ref>PMID:12087098</ref> <ref>PMID:14651849</ref> <ref>PMID:12718876</ref> <ref>PMID:15268862</ref> <ref>PMID:15545625</ref> <ref>PMID:15467718</ref> <ref>PMID:15718470</ref> <ref>PMID:18925875</ref> <ref>PMID:18762023</ref> <ref>PMID:18497260</ref> <ref>PMID:20537536</ref> <ref>PMID:20516213</ref> <ref>PMID:21659604</ref> 
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== Publication Abstract from PubMed ==
The mechanistic target of rapamycin complex 1 (mTORC1) controls cell growth and metabolism in response to nutrients, energy levels, and growth factors. It contains the atypical kinase mTOR and the RAPTOR subunit that binds to the Tor signalling sequence (TOS) motif of substrates and regulators. mTORC1 is activated by the small GTPase RHEB (Ras homologue enriched in brain) and inhibited by PRAS40. Here we present the 3.0 angstrom cryo-electron microscopy structure of mTORC1 and the 3.4 angstrom structure of activated RHEB-mTORC1. RHEB binds to mTOR distally from the kinase active site, yet causes a global conformational change that allosterically realigns active-site residues, accelerating catalysis. Cancer-associated hyperactivating mutations map to structural elements that maintain the inactive state, and we provide biochemical evidence that they mimic RHEB relieving auto-inhibition. We also present crystal structures of RAPTOR-TOS motif complexes that define the determinants of TOS recognition, of an mTOR FKBP12-rapamycin-binding (FRB) domain-substrate complex that establishes a second substrate-recruitment mechanism, and of a truncated mTOR-PRAS40 complex that reveals PRAS40 inhibits both substrate-recruitment sites. These findings help explain how mTORC1 selects its substrates, how its kinase activity is controlled, and how it is activated by cancer-associated mutations.

Mechanisms of mTORC1 activation by RHEB and inhibition by PRAS40.,Yang H, Jiang X, Li B, Yang HJ, Miller M, Yang A, Dhar A, Pavletich NP Nature. 2017 Dec 13. pii: nature25023. doi: 10.1038/nature25023. PMID:29236692<ref>PMID:29236692</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
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<div class="pdbe-citations 5wbu" style="background-color:#fffaf0;"></div>

==See Also==
*[[Serine/threonine protein kinase 3D structures|Serine/threonine protein kinase 3D structures]]
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Homo sapiens]]
[[Category: Large Structures]]
[[Category: Pavletich NP]]
[[Category: Yang H]]