Brito, CláudiaSerna, MarinaGuerra, PabloLlorca, ÓscarSurrey, Thomas2024-02-142024-02-142024Brito C, Serna M, Guerra P, Llorca O, Surrey T. Transition of human γ-tubulin ring complex into a closed conformation during microtubule nucleation. Science. 2024 Feb 23;383(6685):870-6. DOI: 10.1126/science.adk61600036-8075http://hdl.handle.net/10230/59109Microtubules are essential for intracellular organization and chromosome segregation. They are nucleated by the γ-tubulin ring complex (γTuRC). However, isolated vertebrate γTuRC adopts an open conformation that deviates from the microtubule structure, raising the question of the nucleation mechanism. Here we determine cryo-electron microscopy structures of human γTuRC bound to a nascent microtubule. Structural changes of the complex into a closed conformation ensure that γTuRC templates the 13-protofilament microtubules that exist in human cells. Closure is mediated by a latch that interacts with incorporating tubulin, making it part of the closing mechanism. Further rearrangements involve all γ-tubulin ring complex subunits and the removal of the actin-containing luminal bridge. Our proposed mechanism of microtubule nucleation by human γTuRC relies on large-scale structural changes that are likely the target of regulation in cells.application/pdfengThis is the author’s version of the work. It is posted here by permission of the AAAS for personal use, not for redistribution. The definitive version was published in Science, DOI: 10.1126/science.adk6160.MicrotúbulsTubulinesinfo:eu-repo/semantics/articlehttp://dx.doi.org/10.1126/science.adk6160info:eu-repo/semantics/openAccess