{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,3]],"date-time":"2026-09-03T17:16:44Z","timestamp":1788455804786,"version":"build-2803163510"},"reference-count":31,"publisher":"eLife Sciences Publications, Ltd","license":[{"start":{"date-parts":[[2026,9,3]],"date-time":"2026-09-03T00:00:00Z","timestamp":1788393600000},"content-version":"vor","delay-in-days":0,"URL":"http:\/\/creativecommons.org\/licenses\/by\/4.0\/"},{"start":{"date-parts":[[2026,9,3]],"date-time":"2026-09-03T00:00:00Z","timestamp":1788393600000},"content-version":"am","delay-in-days":0,"URL":"http:\/\/creativecommons.org\/licenses\/by\/4.0\/"},{"start":{"date-parts":[[2026,9,3]],"date-time":"2026-09-03T00:00:00Z","timestamp":1788393600000},"content-version":"tdm","delay-in-days":0,"URL":"http:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/100000002","name":"National Institutes of Health","doi-asserted-by":"crossref","award":["R01GM098543"],"award-info":[{"award-number":["R01GM098543"]}],"id":[{"id":"10.13039\/100000002","id-type":"DOI","asserted-by":"crossref"}]},{"award":["R01GM098543"],"award-info":[{"award-number":["R01GM098543"]}],"id":[{"id":"https:\/\/ror.org\/01cwqze88","id-type":"ROR","asserted-by":"publisher"}]},{"DOI":"10.13039\/100000002","name":"National Institutes of Health","doi-asserted-by":"crossref","award":["R35GM156385"],"award-info":[{"award-number":["R35GM156385"]}],"id":[{"id":"10.13039\/100000002","id-type":"DOI","asserted-by":"crossref"}]},{"award":["R35GM156385"],"award-info":[{"award-number":["R35GM156385"]}],"id":[{"id":"https:\/\/ror.org\/01cwqze88","id-type":"ROR","asserted-by":"publisher"}]},{"DOI":"10.13039\/100000928","name":"Welch Foundation","doi-asserted-by":"crossref","award":["I-2246-20250403"],"award-info":[{"award-number":["I-2246-20250403"]}],"id":[{"id":"10.13039\/100000928","id-type":"DOI","asserted-by":"crossref"}]},{"award":["I-2246-20250403"],"award-info":[{"award-number":["I-2246-20250403"]}],"id":[{"id":"https:\/\/ror.org\/00np6vq88","id-type":"ROR","asserted-by":"publisher"}]}],"content-domain":{"domain":["elifesciences.org"],"crossmark-restriction":false},"short-container-title":[],"abstract":"<jats:p>\n                    Defining quantitative biochemical mechanisms of microtubule dynamics and regulation is a current challenge. Stu2\/XMAP215-family polymerases use tubulin-binding TOG domains to catalyze microtubule growth, but how polymerase activity results from the number and tubulin-binding properties of TOGs is not understood. We tested whether an enzyme-like biochemical model for the unrelated actin polymerase Ena\/VASP could be applied to quantitatively relate Stu2 microtubule polymerase activity to the number of its TOGs, and the rate constants governing their interactions with tubulin. Stu2 activity displayed enzyme-like characteristics consistent with the biochemical model: Stu2 stimulated microtubule growth rates with hyperbolic dependence on tubulin concentration, and the amount of Stu2 on the microtubule end did not vary with tubulin concentration (microtubule growth rate). Complementary measurements of TOG:tubulin binding revealed high affinity (10 nM) and slow dissociation (0.03 s\n                    <jats:sup>\u20131<\/jats:sup>\n                    ). The polymerase and binding measurements can be unified within the biochemical model: Stu2 operates with high efficiency, acting as a tubulin-shuttling antenna on the microtubule end that is primarily limited by the rate of tubulin:TOG association. Our work thus provides a quantitative biochemical mechanism for TOG-based polymerases. That unrelated microtubule and actin polymerases use the same enzyme-like mechanism provides an example of convergent evolution in the cytoskeleton.\n                  <\/jats:p>","DOI":"10.7554\/elife.107818","type":"journal-article","created":{"date-parts":[[2025,7,25]],"date-time":"2025-07-25T14:30:32Z","timestamp":1753453832000},"update-policy":"https:\/\/doi.org\/10.7554\/elife.107818","source":"Crossref","is-referenced-by-count":0,"title":["A biochemical mechanism for Stu2\/XMAP215-family microtubule polymerases"],"prefix":"10.7554","volume":"14","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-5126-1089","authenticated-orcid":true,"given":"Binnu","family":"Gangadharan","sequence":"first","affiliation":[{"id":[{"id":"https:\/\/ror.org\/05byvp690","id-type":"ROR","asserted-by":"publisher"}],"name":"Department of Biophysics, University of Texas Southwestern Medical Center","place":["Dallas, United States"]}],"role":[{"role":"author","vocabulary":"crossref"},{"role":"investigation","vocabulary":"credit"},{"role":"writing-original-draft","vocabulary":"credit"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-8657-9348","authenticated-orcid":true,"given":"Daniel L","family":"Kober","sequence":"additional","affiliation":[{"id":[{"id":"https:\/\/ror.org\/05byvp690","id-type":"ROR","asserted-by":"publisher"}],"name":"Department of Biochemistry, University of Texas Southwestern Medical Center","place":["Dallas, United States"]}],"role":[{"role":"author","vocabulary":"crossref"},{"role":"investigation","vocabulary":"credit"},{"role":"writing-review-editing","vocabulary":"credit"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-6551-3307","authenticated-orcid":true,"given":"Luke M","family":"Rice","sequence":"additional","affiliation":[{"id":[{"id":"https:\/\/ror.org\/05byvp690","id-type":"ROR","asserted-by":"publisher"}],"name":"Department of Biophysics, University of Texas Southwestern Medical Center","place":["Dallas, United States"]},{"id":[{"id":"https:\/\/ror.org\/05byvp690","id-type":"ROR","asserted-by":"publisher"}],"name":"Department of Biochemistry, University of Texas Southwestern Medical Center","place":["Dallas, United States"]}],"role":[{"role":"author","vocabulary":"crossref"},{"role":"corresponding-author","vocabulary":"crossref"},{"role":"conceptualization","vocabulary":"credit"},{"role":"data-curation","vocabulary":"credit"},{"role":"funding-acquisition","vocabulary":"credit"},{"role":"project-administration","vocabulary":"credit"},{"role":"supervision","vocabulary":"credit"},{"role":"writing-original-draft","vocabulary":"credit"},{"role":"writing-review-editing","vocabulary":"credit"}]}],"member":"4374","published-online":{"date-parts":[[2026,9,3]]},"reference":[{"key":"bib1","doi-asserted-by":"publisher","first-page":"711","DOI":"10.1038\/nrm4084","type":"journal-article","article-title":"Control of microtubule organization and dynamics: two ends in the limelight","volume":"16","author":"Akhmanova","year":"2015","journal-title":"Nature Reviews. Molecular Cell Biology"},{"key":"bib2","doi-asserted-by":"publisher","first-page":"355","DOI":"10.1016\/j.str.2007.01.012","type":"journal-article","article-title":"Crystal structure of a TOG domain: conserved features of XMAP215\/Dis1-family TOG domains and implications for tubulin binding","volume":"15","author":"Al-Bassam","year":"2007","journal-title":"Structure"},{"key":"bib3","doi-asserted-by":"publisher","first-page":"604","DOI":"10.1016\/j.tcb.2011.06.007","type":"journal-article","article-title":"Regulation of microtubule dynamics by TOG-domain proteins XMAP215\/Dis1 and CLASP","volume":"21","author":"Al-Bassam","year":"2011","journal-title":"Trends in Cell Biology"},{"key":"bib4","doi-asserted-by":"publisher","first-page":"857","DOI":"10.1126\/science.1221698","type":"journal-article","article-title":"A TOG:\u03b1\u03b2-tubulin complex structure reveals conformation-based mechanisms for a microtubule polymerase","volume":"337","author":"Ayaz","year":"2012","journal-title":"Science"},{"key":"bib5","doi-asserted-by":"publisher","DOI":"10.7554\/eLife.03069","type":"journal-article","article-title":"A tethered delivery mechanism explains the catalytic action of a microtubule polymerase","volume":"3","author":"Ayaz","year":"2014","journal-title":"eLife"},{"key":"bib6","doi-asserted-by":"publisher","first-page":"456","DOI":"10.1038\/emboj.2010.348","type":"journal-article","article-title":"Molecular mechanism of Ena\/VASP-mediated actin-filament elongation","volume":"30","author":"Breitsprecher","year":"2011","journal-title":"The EMBO Journal"},{"key":"bib7","doi-asserted-by":"publisher","first-page":"79","DOI":"10.1016\/j.cell.2007.11.043","type":"journal-article","article-title":"XMAP215 is a processive microtubule polymerase","volume":"132","author":"Brouhard","year":"2008","journal-title":"Cell"},{"key":"bib8","doi-asserted-by":"publisher","first-page":"451","DOI":"10.1038\/s41580-018-0009-y","type":"journal-article","article-title":"Microtubule dynamics: an interplay of biochemistry and mechanics","volume":"19","author":"Brouhard","year":"2018","journal-title":"Nature Reviews. Molecular Cell Biology"},{"key":"bib9","doi-asserted-by":"publisher","first-page":"1490","DOI":"10.1091\/mbc.E19-02-0093","type":"journal-article","article-title":"Microtubule polymerase and processive plus-end tracking functions originate from distinct features within TOG domain arrays","volume":"30","author":"Cook","year":"2019","journal-title":"Molecular Biology of the Cell"},{"key":"bib10","doi-asserted-by":"publisher","DOI":"10.1002\/0471142727.mb1420s92","type":"journal-article","article-title":"Computer control of microscopes using \u00b5Manager","volume":"Chapter 14","author":"Edelstein","year":"2010","journal-title":"Current Protocols in Molecular Biology"},{"key":"bib11","doi-asserted-by":"publisher","DOI":"10.1083\/jcb.202012144","type":"journal-article","article-title":"XMAP215 promotes microtubule catastrophe by disrupting the growing microtubule end","volume":"220","author":"Farmer","year":"2021","journal-title":"The Journal of Cell Biology"},{"key":"bib12","doi-asserted-by":"publisher","first-page":"4597","DOI":"10.1038\/sj.emboj.7601874","type":"journal-article","article-title":"Structural basis for the recruitment of profilin-actin complexes during filament elongation by Ena\/VASP","volume":"26","author":"Ferron","year":"2007","journal-title":"The EMBO Journal"},{"key":"bib13","doi-asserted-by":"publisher","first-page":"2203","DOI":"10.1083\/jcb.105.5.2203","type":"journal-article","article-title":"A microtubule-associated protein from Xenopus eggs that specifically promotes assembly at the plus-end","volume":"105","author":"Gard","year":"1987","journal-title":"The Journal of Cell Biology"},{"key":"bib14","doi-asserted-by":"publisher","DOI":"10.7554\/eLife.10113","type":"journal-article","article-title":"A mutation uncouples the tubulin conformational and GTPase cycles, revealing allosteric control of microtubule dynamics","volume":"4","author":"Geyer","year":"2015","journal-title":"eLife"},{"key":"bib15","doi-asserted-by":"publisher","DOI":"10.7554\/eLife.34574","type":"journal-article","article-title":"Design principles of a microtubule polymerase","volume":"7","author":"Geyer","year":"2018","journal-title":"eLife"},{"key":"bib16","doi-asserted-by":"publisher","DOI":"10.1101\/cshperspect.a022608","type":"journal-article","article-title":"Microtubules and microtubule-associated proteins","volume":"10","author":"Goodson","year":"2018","journal-title":"Cold Spring Harbor Perspectives in Biology"},{"key":"bib17","doi-asserted-by":"publisher","first-page":"777","DOI":"10.1038\/s41580-021-00399-x","type":"journal-article","article-title":"Regulation of microtubule dynamics, mechanics and function through the growing tip","volume":"22","author":"Gudimchuk","year":"2021","journal-title":"Nature Reviews. Molecular Cell Biology"},{"key":"bib18","doi-asserted-by":"publisher","first-page":"571","DOI":"10.1083\/jcb.201003014","type":"journal-article","article-title":"VASP is a processive actin polymerase that requires monomeric actin for barbed end association","volume":"191","author":"Hansen","year":"2010","journal-title":"The Journal of Cell Biology"},{"key":"bib19","doi-asserted-by":"publisher","first-page":"307","DOI":"10.1038\/s41580-020-0214-3","type":"journal-article","article-title":"The tubulin code and its role in controlling microtubule properties and functions","volume":"21","author":"Janke","year":"2020","journal-title":"Nature Reviews. Molecular Cell Biology"},{"key":"bib20","doi-asserted-by":"publisher","first-page":"8636","DOI":"10.1021\/bi2005174","type":"journal-article","article-title":"Design, overexpression, and purification of polymerization-blocked yeast \u03b1\u03b2-tubulin mutants","volume":"50","author":"Johnson","year":"2011","journal-title":"Biochemistry"},{"key":"bib21","doi-asserted-by":"publisher","DOI":"10.7554\/eLife.38922","type":"journal-article","article-title":"Structural basis of tubulin recruitment and assembly by microtubule polymerases with tumor overexpressed gene (TOG) domain arrays","volume":"7","author":"Nithianantham","year":"2018","journal-title":"eLife"},{"key":"bib22","doi-asserted-by":"publisher","first-page":"1465","DOI":"10.1002\/j.1460-2075.1988.tb02964.x","type":"journal-article","article-title":"Cold-sensitive and caffeine-supersensitive mutants of the Schizosaccharomyces pombe dis genes implicated in sister chromatid separation during mitosis","volume":"7","author":"Ohkura","year":"1988","journal-title":"The EMBO Journal"},{"key":"bib23","doi-asserted-by":"publisher","DOI":"10.21769\/BioProtoc.4152","type":"journal-article","article-title":"Kinetic analysis of a protein-protein complex to determine its Dissociation Constant (KD) and the Effective Concentration (EC50) of an interplaying effector molecule using bio-layer interferometry","volume":"11","author":"Orthwein","year":"2021","journal-title":"Bio-Protocol"},{"key":"bib24","doi-asserted-by":"publisher","first-page":"28087","DOI":"10.1074\/jbc.M114.584300","type":"journal-article","article-title":"Stu2, the budding yeast XMAP215\/Dis1 homolog, promotes assembly of yeast microtubules by increasing growth rate and decreasing catastrophe frequency","volume":"289","author":"Podolski","year":"2014","journal-title":"The Journal of Biological Chemistry"},{"key":"bib25","doi-asserted-by":"publisher","first-page":"707","DOI":"10.1038\/nchembio.2007.31","type":"journal-article","article-title":"Sortagging: a versatile method for protein labeling","volume":"3","author":"Popp","year":"2007","journal-title":"Nature Chemical Biology"},{"key":"bib26","doi-asserted-by":"publisher","first-page":"1422","DOI":"10.1038\/ncb3241","type":"journal-article","article-title":"Complementary activities of TPX2 and chTOG constitute an efficient importin-regulated microtubule nucleation module","volume":"17","author":"Roostalu","year":"2015","journal-title":"Nature Cell Biology"},{"key":"bib27","doi-asserted-by":"publisher","first-page":"1002","DOI":"10.1042\/BST0371002","type":"journal-article","article-title":"The role of TOG domains in microtubule plus end dynamics","volume":"37","author":"Slep","year":"2009","journal-title":"Biochemical Society Transactions"},{"key":"bib28","doi-asserted-by":"publisher","first-page":"575","DOI":"10.1038\/s41556-018-0091-6","type":"journal-article","article-title":"XMAP215 is a microtubule nucleation factor that functions synergistically with the \u03b3-tubulin ring complex","volume":"20","author":"Thawani","year":"2018","journal-title":"Nature Cell Biology"},{"key":"bib29","doi-asserted-by":"publisher","first-page":"275","DOI":"10.1016\/s0014-5793(02)03356-2","type":"journal-article","article-title":"The vasodilator-stimulated phosphoprotein promotes actin polymerisation through direct binding to monomeric actin","volume":"529","author":"Walders-Harbeck","year":"2002","journal-title":"FEBS Letters"},{"key":"bib30","doi-asserted-by":"publisher","DOI":"10.1083\/jcb.202202102","type":"journal-article","article-title":"Tubulin isotype regulation maintains asymmetric requirement for \u03b1-tubulin over \u03b2-tubulin","volume":"222","author":"Wethekam","year":"2023","journal-title":"The Journal of Cell Biology"},{"key":"bib31","doi-asserted-by":"publisher","first-page":"2741","DOI":"10.1073\/pnas.1016498108","type":"journal-article","article-title":"XMAP215 polymerase activity is built by combining multiple tubulin-binding TOG domains and a basic lattice-binding region","volume":"108","author":"Widlund","year":"2011","journal-title":"PNAS"}],"container-title":["eLife"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/cdn.elifesciences.org\/articles\/107818\/elife-107818-v1.pdf","content-type":"application\/pdf","content-version":"vor","intended-application":"text-mining"},{"URL":"https:\/\/cdn.elifesciences.org\/articles\/107818\/elife-107818-v1.xml","content-type":"application\/xml","content-version":"vor","intended-application":"text-mining"},{"URL":"https:\/\/elifesciences.org\/articles\/107818","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,9,3]],"date-time":"2026-09-03T16:26:18Z","timestamp":1788452778000},"score":1,"resource":{"primary":{"URL":"https:\/\/elifesciences.org\/articles\/107818"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2026,9,3]]},"references-count":31,"alternative-id":["10.7554\/eLife.107818"],"URL":"https:\/\/doi.org\/10.7554\/elife.107818","archive":["CLOCKSS"],"relation":{"has-preprint":[{"id-type":"doi","id":"10.1101\/2025.06.09.658552","asserted-by":"subject"}],"is-same-as":[{"id-type":"doi","id":"10.7554\/eLife.107818.3","asserted-by":"subject"}],"is-version-of":[{"id-type":"doi","id":"10.7554\/eLife.107818.1","asserted-by":"subject"},{"id-type":"doi","id":"10.7554\/eLife.107818.2","asserted-by":"subject"}]},"ISSN":["2050-084X"],"issn-type":[{"value":"2050-084X","type":"electronic"}],"subject":[],"published":{"date-parts":[[2026,9,3]]},"assertion":[{"value":"single anonymised","name":"peer_review_transparency","label":"Peer review transparency","group":{"name":"peer_review_taxonomy"}},{"value":"other reviewer(s), editor","name":"peer_review_interaction","label":"Peer review interaction","group":{"name":"peer_review_taxonomy"}},{"value":"review summaries, review reports, author\/editor communication, reviewer identities reviewer opt in, editor identities","name":"peer_review_published","label":"Peer review published","group":{"name":"peer_review_taxonomy"}},{"value":"open (sign in with ORCID iD required)","name":"post_publication_commenting","label":"Post publication commenting","group":{"name":"post_publication_commenting"}}],"article-number":"RP107818"}}