8QV3

Structure of the y-Tubulin Small Complex (yTuSC) as part of the native y-Tubulin Ring Complex (yTuRC) capping microtubule minus ends at the spindle pole body

This is a non-PDB format compatible entry.

Summary for 8QV3

• Entry DOI: 10.2210/pdb8qv3/pdb
• EMDB information: 18666
• Descriptor: Tubulin gamma chain, Spindle pole body component, Spindle pole body component 110, ... (10 entities in total)
• Functional Keywords: microtubule nucleation, mtoc, y-tubulin, spb, cell cycle
• Biological source: Saccharomyces cerevisiae (baker's yeast); More
• Total number of polymer chains: 12
• Total formula weight: 738297.00

Authors

Dendooven, T.,Yatskevich, S.,Burt, A.,Bellini, D.,Kilmartin, J.,Barford, D. (deposition date: 2023-10-17, release date: 2024-04-24, Last modification date: 2024-07-31)

Primary citation

Dendooven, T.,Yatskevich, S.,Burt, A.,Chen, Z.A.,Bellini, D.,Rappsilber, J.,Kilmartin, J.V.,Barford, D.
Structure of the native gamma-tubulin ring complex capping spindle microtubules.
Nat.Struct.Mol.Biol., 31:1134-1144, 2024

PubMed Abstract: Microtubule (MT) filaments, composed of α/β-tubulin dimers, are fundamental to cellular architecture, function and organismal development. They are nucleated from MT organizing centers by the evolutionarily conserved γ-tubulin ring complex (γTuRC). However, the molecular mechanism of nucleation remains elusive. Here we used cryo-electron tomography to determine the structure of the native γTuRC capping the minus end of a MT in the context of enriched budding yeast spindles. In our structure, γTuRC presents a ring of γ-tubulin subunits to seed nucleation of exclusively 13-protofilament MTs, adopting an active closed conformation to function as a perfect geometric template for MT nucleation. Our cryo-electron tomography reconstruction revealed that a coiled-coil protein staples the first row of α/β-tubulin of the MT to alternating positions along the γ-tubulin ring of γTuRC. This positioning of α/β-tubulin onto γTuRC suggests a role for the coiled-coil protein in augmenting γTuRC-mediated MT nucleation. Based on our results, we describe a molecular model for budding yeast γTuRC activation and MT nucleation.

PubMed: 38609662
DOI: 10.1038/s41594-024-01281-y

Experimental method

ELECTRON MICROSCOPY (8.2 Å)