Cryo-EM structures of γ-TuRC reveal molecular insights into microtubule nucleation

Microtubules within cells often have 13 protofilaments but are nucleated by multi-protein y-TuRCs complexes that display 14 γ-tubulin molecules. High-resolution cryo-EM structures of γ-TuRCs after nucleation show that these γ-TuRCs ‘close’ during nucleation to display only 13 γ-tubulin molecules for protofilament assembly.