Structural basis for mTORC1 regulation by the CASTOR1-GATOR2 complex

Structural basis for mTORC1 regulation by the CASTOR1-GATOR2 complex | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Biological Sciences - Article Structural basis for mTORC1 regulation by the CASTOR1-GATOR2 complex Rachel Jansen, Clement Maghe, Karla Tapia, Selina Wu, Serim Yang, and 3 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-5073364/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 25 Jul, 2025 Read the published version in Nature Structural & Molecular Biology → Version 1 posted You are reading this latest preprint version Abstract Mechanistic target of rapamycin complex 1 (mTORC1) is a nutrient-responsive master regulator of metabolism. Amino acids control the recruitment and activation of mTORC1 at the lysosome via the nucleotide loading state of the heterodimeric Rag GTPases. Under low nutrients, including arginine (Arg), the GTPase activating protein (GAP) complex, GATOR1, promotes GTP hydrolysis on RagA/B, inactivating mTORC1. GATOR1 is regulated by the cage-like GATOR2 complex and cytosolic amino acid sensors. To understand how the Arg-sensor CASTOR1 binds to GATOR2 to disinhibit GATOR1 under low cytosolic Arg, we determined the cryo-EM structure of GATOR2 bound to apo-CASTOR1. Two MIOS WD40 domain β-propellers of the GATOR2 cage engage with both subunits of a single CASTOR1 homodimer. Each propeller binds to a negatively charged MIOS-binding interface (MBI) on CASTOR1 that is distal to the Arg pocket. The structure shows how Arg-triggered loop ordering in CASTOR1 blocks the MBI, switches off its binding to GATOR2, and so activates mTORC1. Biological sciences/Structural biology/Electron microscopy/Cryoelectron microscopy Biological sciences/Cell biology/Cell signalling/Nutrient signalling Full Text Additional Declarations Yes there is potential Competing Interest. J.H.H. is a co-founder and shareholder of Casma Therapeutics, has received research funding from Genentech and Hoffmann-La Roche, and has consulted for Corsalex. R.Z. is a cofounder and shareholder of Frontier Medicines, science advisory board member for Nine Square Therapeutics and receives research funding from Genentech. The other authors declare no competing interests. Supplementary Files EDMovie1.mp4 Extended Data Movie 1: Structural rearrangement of GATOR2 upon interaction with CASTOR1. Visualization of GATOR2 prior to interaction with CASTOR1. CASTOR1 appears and GATOR2 reorients to engage CASTOR1 through MIOS subunits Cite Share Download PDF Status: Published Journal Publication published 25 Jul, 2025 Read the published version in Nature Structural & Molecular Biology → Version 1 posted You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-5073364","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Biological Sciences - Article","associatedPublications":[],"authors":[{"id":419925607,"identity":"728a04e0-2af9-4f59-b6a2-775133bbf27f","order_by":0,"name":"Rachel Jansen","email":"","orcid":"","institution":"UC Berkeley","correspondingAuthor":false,"prefix":"","firstName":"Rachel","middleName":"","lastName":"Jansen","suffix":""},{"id":419925608,"identity":"513d6826-a56f-49c7-a774-ab5f9ff6184b","order_by":1,"name":"Clement Maghe","email":"","orcid":"","institution":"University of California, Berkeley","correspondingAuthor":false,"prefix":"","firstName":"Clement","middleName":"","lastName":"Maghe","suffix":""},{"id":419925609,"identity":"cba241ea-3440-43ca-9d3d-3e5493e319b0","order_by":2,"name":"Karla Tapia","email":"","orcid":"","institution":"University of California, Berkeley","correspondingAuthor":false,"prefix":"","firstName":"Karla","middleName":"","lastName":"Tapia","suffix":""},{"id":419925610,"identity":"a7a4fc18-3827-429e-af36-613d355f0e0b","order_by":3,"name":"Selina Wu","email":"","orcid":"","institution":"University of California, Berkeley","correspondingAuthor":false,"prefix":"","firstName":"Selina","middleName":"","lastName":"Wu","suffix":""},{"id":419925611,"identity":"e6a751f0-9718-435d-a4ae-e44724ebe7dc","order_by":4,"name":"Serim Yang","email":"","orcid":"","institution":"University of California, Berkeley","correspondingAuthor":false,"prefix":"","firstName":"Serim","middleName":"","lastName":"Yang","suffix":""},{"id":419925612,"identity":"994665f1-0571-46e5-9f06-6e063f01da47","order_by":5,"name":"Xuefeng Ren","email":"","orcid":"https://orcid.org/0000-0002-4822-4316","institution":"University of California, Berkeley","correspondingAuthor":false,"prefix":"","firstName":"Xuefeng","middleName":"","lastName":"Ren","suffix":""},{"id":419925613,"identity":"0c3b5555-3d4f-4a36-acff-ab79b6fb5195","order_by":6,"name":"Roberto Zoncu","email":"","orcid":"https://orcid.org/0000-0003-1611-1891","institution":"University of California, Berkeley","correspondingAuthor":false,"prefix":"","firstName":"Roberto","middleName":"","lastName":"Zoncu","suffix":""},{"id":419925606,"identity":"a3c82da1-24ef-499c-8f56-e86f69f5333f","order_by":7,"name":"James Hurley","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA+0lEQVRIiWNgGAWjYBACxmYGNiBlwcDA3gOkDzDIgIV5CGuRAKo6A9bCQ1ALEEC1SOQQqYW5nTvtMe8eCTmDm28PPq44Y8PDL5HA+OBtGz6H8W435nkmYWxwOy/Z8MyNNB7JGQnMhnPxa9kmzXNAInHD7RwzyYYPh3kMbiSwSfMSoaV+w80z5j8bPvznsb+RwP6bGC0JBjd4zBgbbhzgMZBIYGMmpEVyzgEJw5ln8pIlG84k80icedgsOeccbi2G/We3Sbw5YCPPd/zswY8Nx+zk+NuTD354U4ZHSwOUoXAAJiSQ2IBNJRzIwxlwdfwHsCkcBaNgFIyCEQwAYN9S6i/v4QIAAAAASUVORK5CYII=","orcid":"https://orcid.org/0000-0001-5054-5445","institution":"University of California, Berkeley","correspondingAuthor":true,"prefix":"","firstName":"James","middleName":"","lastName":"Hurley","suffix":""}],"badges":[],"createdAt":"2024-09-11 20:00:16","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-5073364/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-5073364/v1","draftVersion":[],"editorialEvents":[{"content":"https://doi.org/10.1038/s41594-025-01635-0","type":"published","date":"2025-07-25T04:00:00+00:00"}],"editorialNote":"","failedWorkflow":false,"files":[{"id":88506151,"identity":"dcb8819e-35d0-4ddf-9e4d-f929e3d86349","added_by":"auto","created_at":"2025-08-07 07:31:53","extension":"pdf","order_by":1,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":7896196,"visible":true,"origin":"","legend":"Article File","description":"","filename":"JansenNaturerevision1.pdf","url":"https://assets-eu.researchsquare.com/files/rs-5073364/v1_covered_af92e27f-91df-4053-b066-253c36dc4bd4.pdf"},{"id":82589910,"identity":"13678df4-376e-4ab7-8ea8-30bf22a0185e","added_by":"auto","created_at":"2025-05-13 07:53:09","extension":"mp4","order_by":1,"title":"","display":"","copyAsset":false,"role":"supplement","size":8575817,"visible":true,"origin":"","legend":"\u003cp\u003eExtended Data Movie 1: Structural rearrangement of GATOR2 upon interaction with CASTOR1. 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