Yixin Xu


Last Name

Xu

First Name

Yixin

ORCID

0000-0003-0014-3899

Organisational unit

09763 - Wieczorek, Michal / Wieczorek, Michal

Filters

2024 - 20253
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Publications 1 - 3 of 3
  • Partial closure of the γ-tubulin ring complex by CDK5RAP2 activates microtubule nucleation
    Item type: Journal Article
    Xu, Yixin; Muñoz-Hernández, Hugo; Krutyhołowa, Rościsław; et al. (2024)
    Developmental Cell
    Microtubule nucleation is templated by the γ-tubulin ring complex (γ-TuRC), but its structure deviates from the geometry of α-/β-tubulin in the microtubule, explaining the complex’s poor nucleating activity. Several proteins may activate the γ-TuRC, but the mechanisms underlying activation are not known. Here, we determined the structure of the porcine γ-TuRC purified using CDK5RAP2’s centrosomin motif 1 (CM1). We identified an unexpected conformation of the γ-TuRC bound to multiple protein modules containing MZT2, GCP2, and CDK5RAP2, resulting in a long-range constriction of the γ-tubulin ring that brings it in closer agreement with the 13-protofilament microtubule. Additional CDK5RAP2 promoted γ-TuRC decoration and stimulated the microtubule-nucleating activities of the porcine γ-TuRC and a reconstituted, CM1-free human complex in single-molecule assays. Our results provide a structural mechanism for the control of microtubule nucleation by CM1 proteins and identify conformational transitions in the γ-TuRC that prime it for microtubule nucleation.
  • Structure of the microtubule-anchoring factor NEDD1 bound to the γ-tubulin ring complex
    Item type: Journal Article
    Muñoz-Hernández, Hugo; Xu, Yixin; Pellicer Camardiel, Aitor; et al. (2025)
    Journal of Cell Biology
    The γ-tubulin ring complex (γ-TuRC) is an essential multiprotein assembly that provides a template for microtubule nucleation. The γ-TuRC is recruited to microtubule-organizing centers (MTOCs) by the evolutionarily conserved attachment factor NEDD1. However, the structural basis of the NEDD1-γ-TuRC interaction is not known. Here, we report cryo-EM structures of NEDD1 bound to the human γ-TuRC in the absence or presence of the activating factor CDK5RAP2. We found that the C-terminus of NEDD1 forms a tetrameric α-helical assembly that contacts the lumen of the γ-TuRC cone and orients its microtubule-binding domain away from the complex. The structure of the γ-TuRC simultaneously bound to NEDD1 and CDK5RAP2 reveals that both factors can associate with the "open" conformation of the complex. Our results show that NEDD1 does not induce substantial conformational changes in the γ-TuRC but suggest that anchoring of γ-TuRC-capped microtubules by NEDD1 would be structurally compatible with the significant conformational changes experienced by the γ-TuRC during microtubule nucleation.
  • Structure of the microtubule anchoring factor NEDD1 bound to the γ-tubulin ring complex
    Item type: Working Paper
    Muñoz-Hernández, Hugo; Xu, Yixin; Zhang, Daniel Xinbai; et al. (2024)
    bioRxiv
    The γ-tubulin ring complex (γ-TuRC) is an essential multiprotein assembly, in which γ-tubulin, GCP2-6, actin, MZT1 and MZT2 form an asymmetric cone-shaped structure that provides a template for microtubule nucleation. The γ-TuRC is recruited to microtubule organizing centers (MTOCs), such as centrosomes and pre-existing mitotic spindle microtubules, via the evolutionarily-conserved attachment factor NEDD1. NEDD1 contains an N-terminal WD40 domain that binds to microtubules, and a C-terminal domain that associates with the γ-TuRC. However, the structural basis of the NEDD1-γ-TuRC interaction is not known. Here, we report cryo-electron microscopy (cryo-EM) structures of NEDD1 bound to the human γ-TuRC in the absence or presence of the activating factor CDK5RAP2, which interacts with GCP2 to induce conformational changes in the γ-TuRC and promote its microtubule nucleating function. We found that the C-terminus of NEDD1 forms a tetrameric α-helical assembly that contacts the lumen of the γ-TuRC cone, is anchored to GCP4, 5 and 6 via protein modules consisting of MZT1 & GCP3 subcomplexes, and orients its microtubule-binding WD40 domains away from the complex. We biochemically tested our structural models by identifying NEDD1 mutants unable to pull-down γ-tubulin from cultured cells. The structure of the γ-TuRC simultaneously bound to NEDD1 and CDK5RAP2 reveals that both factors can associate with the “open” conformation of the complex. Our results show that NEDD1 does not induce conformational changes in the γ-TuRC, but suggest that anchoring of γ-TuRC-capped microtubules by NEDD1 would be structurally compatible with the significant conformational changes experienced by the γ-TuRC during microtubule nucleation.
Publications 1 - 3 of 3