{
  "abstract": "Microtubules are present in all eukaryotes and are nucleated by multiprotein {gamma}-tubulin ring complexes ({gamma}-TuRCs), ring-shaped structures that contain several copies of the {gamma}-tubulin small complex ({gamma}-TuSC). {gamma}-TuRCs nucleate microtubules via a template-based mechanism in which the positions of {gamma}-tubulins in the {gamma}-TuSCs match the position of {gamma}-tubulin dimers in the microtubule lattice. Although {gamma}-TuSC proteins are highly conserved, other components of the {gamma}-TuRC can vary in different organisms, as can their relative importance. Here, we characterize two different simplified {gamma}-TuRCs from fission yeast Schizosaccharomyces pombe, using recombinant purified proteins and negative stain electron microscopy. We show that a nucleation-incompetent {gamma}-TuRC that contains only {gamma}-TuSC proteins plus the microprotein Mzt1 ({gamma}-TuSC:Mzt1) can form rings as efficiently as a large, nucleation-competent complex (MGM) that additionally contains the proteins Mto1 and Mto2. We find that the position of {gamma}-tubulins in {gamma}-TuSC:Mzt1 are less well defined than in MGM. Comparative modelling using our electron microscopy and crosslinking mass spectrometry data, together with structures of {gamma}-TuRCs from other organisms, suggests that Mto1 and Mto2 form a multimeric outer mantle surrounding the {gamma}-TuSC:Mzt1 {gamma}-TuRC. This mantle may stabilize positions of {gamma}-tubulins within MGM, explaining the microtubule-nucleating ability of MGM and highlighting the diversity of non-{gamma}-TuSC proteins in modulating {gamma}-TuRC structure and function.",
  "abstract_shown": true,
  "affiliations": [
    "The University of Edinburgh"
  ],
  "article_type": "New results",
  "arxiv": null,
  "author_total": 6,
  "authors": [
    {
      "name": "J. D. Le Cornu"
    },
    {
      "name": "S. L. Leong"
    },
    {
      "name": "E. M. Lynch"
    },
    {
      "name": "H. C. Thakur"
    },
    {
      "name": "K. E. Sawin"
    },
    {
      "affs": [
        0
      ],
      "name": "A. G. Cook"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/6eztpxq4zsw9p.bib",
  "cited_by": 0,
  "doi": "10.64898/2026.11.06.764827",
  "fulltext_url": "https://www.biorxiv.org/content/10.64898/2026.11.06.764827v1.full",
  "id": "6eztpxq4zsw9p",
  "issns": [],
  "landing_url": "https://www.biorxiv.org/content/10.64898/2026.11.06.764827v1",
  "language": null,
  "licence": "CC-BY",
  "licence_label": "CC BY",
  "licence_source": "article",
  "licence_url": "https://creativecommons.org/licenses/by/4.0/",
  "metadata_licence": null,
  "native_subjects": [
    [
      "biorxiv",
      "biochemistry"
    ]
  ],
  "openalex": null,
  "pdf_url": "https://www.biorxiv.org/content/10.64898/2026.11.06.764827v1.full.pdf",
  "pmcid": null,
  "pmid": null,
  "published": "2026-11-06",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/6eztpxq4zsw9p.ris",
  "sources": [
    {
      "first_seen": "2026-11-10T00:23:31Z",
      "native_id": "10.64898/2026.11.06.764827",
      "source": "biorxiv",
      "url": "https://www.biorxiv.org/content/10.64898/2026.11.06.764827v1"
    }
  ],
  "subjects": [
    {
      "field": "biochemistry",
      "origin": "biorxiv:biochemistry",
      "subfield": "general"
    }
  ],
  "title": "S. pombe Mto1:Mto2 stabilizes γ-tubulin positions within the γ-TuRC",
  "title_text": "S. pombe Mto1:Mto2 stabilizes γ-tubulin positions within the γ-TuRC",
  "type": "preprint",
  "updated_at": "2026-11-10T00:23:31Z",
  "url": "https://research.draconitic.com/paper/6eztpxq4zsw9p",
  "venue": "bioRxiv",
  "versions": []
}