The identification of XPR1 as a voltage- and phosphate-activated phosphate-permeable ion channel

The identification of XPR1 as a voltage- and phosphate-activated phosphate-permeable ion channel | 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 Article The identification of XPR1 as a voltage- and phosphate-activated phosphate-permeable ion channel Zhao Wang, Hongjiang Wu, Liang Sun, Theodore Wensel, Frank Horrigan, and 1 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-4457423/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 15 May, 2025 Read the published version in Nature Communications → Version 1 posted You are reading this latest preprint version Abstract Maintaining a balance of inorganic phosphate (Pi) is vital for cellular functionality due to Pi's essential role in numerous biological processes. Proper phosphate levels are managed through Pi import and export, facilitated by specific Pi transport proteins. Although the mechanisms of Pi import have been extensively studied, the processes governing Pi export remain less understood. Xenotropic and Polytropic retrovirus Receptor 1 (XPR1) has been identified as the only known Pi export protein in mammals, playing a key role in facilitating Pi efflux from cells. Malfunctions in XPR1 are associated with human diseases, such as primary familial brain calcification and certain cancers, highlighting its critical role in maintaining Pi homeostasis. In this study, we introduce the cryogenic electron microscopy structure of human XPR1 (hXPR1), unveiling a structural arrangement distinct from that of any known ion transporter, with a topology not identified in previous computational predictions. Our structural results suggest that hXPR1 may operate as an ion channel, a hypothesis supported by patch clamp recordings revealing hXPR1's voltage- and Pi-dependent activity and large unitary conductance. Using proteoliposomal uptake assays, we demonstrate that purified and reconstituted hXPR1 catalyzes transport of Pi. Further analysis, including the structure of hXPR1 in presence of Pi, and functional effects of mutating a putative Pi binding site, leads us to propose a plausible ion permeation pathway. Together, our results provide novel perspectives on the Pi transport mechanism of XPR1 and its homologues. Biological sciences/Structural biology/Electron microscopy/Cryoelectron microscopy Biological sciences/Biochemistry/Ion channels/Ligand-gated ion channels Full Text Additional Declarations There is NO Competing Interest. Cite Share Download PDF Status: Published Journal Publication published 15 May, 2025 Read the published version in Nature Communications → 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-4457423","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Article","associatedPublications":[],"authors":[{"id":388734064,"identity":"1206afdc-b455-425d-b357-aa6252fb778d","order_by":0,"name":"Zhao Wang","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAAoElEQVRIiWNgGAWjYDACCRBRcQDBJlLLGZK1MLaRokV+dvPDx7zz7sjrNjAfvM1DjBbGOceMjXm3PTPcdoAt2ZooLcwSCWbSudsOJ5gd4DGTJkoLm0T6N+ncOSAt/N+I08IjkQO0pQFsCxtxWiQkcoqN/xwD+uUwm7HlHGK0yM9I3/hwRs0debPjzQ9vvCFGCwIwk6Z8FIyCUTAKRgE+AAAxTS9iJmeMGQAAAABJRU5ErkJggg==","orcid":"https://orcid.org/0000-0003-4897-9986","institution":"Baylor College of Medicine","correspondingAuthor":true,"prefix":"","firstName":"Zhao","middleName":"","lastName":"Wang","suffix":""},{"id":388734065,"identity":"7716de9f-9d84-4e4f-9f4a-e318481bff28","order_by":1,"name":"Hongjiang Wu","email":"","orcid":"","institution":"Baylor College of Medicine","correspondingAuthor":false,"prefix":"","firstName":"Hongjiang","middleName":"","lastName":"Wu","suffix":""},{"id":388734066,"identity":"eb222aea-9422-49d0-8ad1-d8ed51f7be82","order_by":2,"name":"Liang Sun","email":"","orcid":"","institution":"Baylor College of Medicine","correspondingAuthor":false,"prefix":"","firstName":"Liang","middleName":"","lastName":"Sun","suffix":""},{"id":388734067,"identity":"fe867ee1-db71-4005-b43f-201dea26bb17","order_by":3,"name":"Theodore Wensel","email":"","orcid":"https://orcid.org/0000-0003-3518-9352","institution":"Baylor College of Medicine","correspondingAuthor":false,"prefix":"","firstName":"Theodore","middleName":"","lastName":"Wensel","suffix":""},{"id":388734068,"identity":"57f57456-f623-447f-9b16-f481b0af6288","order_by":4,"name":"Frank Horrigan","email":"","orcid":"https://orcid.org/0000-0001-6703-9581","institution":"Baylor College of Medicine","correspondingAuthor":false,"prefix":"","firstName":"Frank","middleName":"","lastName":"Horrigan","suffix":""},{"id":388734069,"identity":"ddc2b637-e211-42e5-bb52-1309b5261193","order_by":5,"name":"Tong Huo","email":"","orcid":"","institution":"Baylor College of Medicine","correspondingAuthor":false,"prefix":"","firstName":"Tong","middleName":"","lastName":"Huo","suffix":""}],"badges":[],"createdAt":"2024-05-22 00:55:22","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-4457423/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-4457423/v1","draftVersion":[],"editorialEvents":[{"content":"https://doi.org/10.1038/s41467-025-59678-2","type":"published","date":"2025-05-15T04:00:00+00:00"}],"editorialNote":"","failedWorkflow":false,"files":[{"id":82862521,"identity":"762d9e46-9ff1-476d-bfd3-314759cc4d5d","added_by":"auto","created_at":"2025-05-16 07:10:22","extension":"pdf","order_by":1,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":2871604,"visible":true,"origin":"","legend":"Article File","description":"","filename":"XPR1manuscriptrevisionfinal.pdf","url":"https://assets-eu.researchsquare.com/files/rs-4457423/v1_covered_eb29f21b-00c4-4596-a128-b4656c471678.pdf"}],"financialInterests":"There is \u003cb\u003eNO\u003c/b\u003e Competing Interest.","formattedTitle":"The identification of XPR1 as a voltage- and phosphate-activated phosphate-permeable ion channel","fulltext":[],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":false,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":true,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":true,"isAuthorSuppliedPdf":true,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":true,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"nature-portfolio","isNatureJournal":true,"hasQc":false,"allowDirectSubmit":false,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"","title":"Nature Portfolio","twitterHandle":"","acdcEnabled":false,"dfaEnabled":false,"editorialSystem":"ejp","reportingPortfolio":"","inReviewEnabled":true,"inReviewRevisionsEnabled":false},"keywords":"","lastPublishedDoi":"10.21203/rs.3.rs-4457423/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-4457423/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"Maintaining a balance of inorganic phosphate (Pi) is vital for cellular functionality due to Pi's essential role in numerous biological processes. 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Our structural results suggest that hXPR1 may operate as an ion channel, a hypothesis supported by patch clamp recordings revealing hXPR1's voltage- and Pi-dependent activity and large unitary conductance. Using proteoliposomal uptake assays, we demonstrate that purified and reconstituted hXPR1 catalyzes transport of Pi. Further analysis, including the structure of hXPR1 in presence of Pi, and functional effects of mutating a putative Pi binding site, leads us to propose a plausible ion permeation pathway. 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