The augmin complex architecture reveals structural insights into microtubule branching

ABSTRACT: In mitosis, the augmin complex binds to spindle microtubules to recruit the γ-tubulin ring complex (γ-TuRC), the principal microtubule nucleator, for the formation of branched microtubules. Our understanding of augmin-mediated microtubule branching is strongly hampered by the lack of structural information on the augmin complex. Here we elucidate the molecular architecture and define the conformational plasticity of the augmin complex using an integrative structural biology approach. The elongated structure of the augmin complex is characterised by extensive coiled-coil segments and comprises two structural elements with distinct but complementary functions in γ-TuRC and microtubule binding, linked by a flexible hinge. The augmin complex is recruited to microtubules via a composite microtubule binding site comprising a positively charged unordered extension and two Calponin homology domains. Our study provides the structural basis for augmin function in branched microtubule formation, decisively fostering our understanding of spindle formation in mitosis.

INSTRUMENT(S): Orbitrap Fusion Lumos

ORGANISM(S): Xenopus Laevis (african Clawed Frog)

SUBMITTER: Erik Zupa  

LAB HEAD: Stefan Pfeffer

PROVIDER: PXD034895 | Pride | 2022-10-13

REPOSITORIES: Pride