Cell
Volume 169, Issue 6, 1 June 2017, Pages 1078-1089.e13
Journal home page for Cell

Article
Structural Basis for Mitotic Centrosome Assembly in Flies

https://doi.org/10.1016/j.cell.2017.05.030Get rights and content
Under a Creative Commons license
open access

Highlights

  • The conserved PReM and CM2 domains of Cnn co-assemble into micron-scale structures

  • The crystal structure of the PReM-LZ:CM2 complex is solved to 1.82 Å

  • Mutations that block PReM-LZ:CM2 assembly in vitro block centrosome assembly in vivo

  • Phosphorylation of PReM by Polo/Plk1 promotes scaffold assembly in vitro and in vivo

Summary

In flies, Centrosomin (Cnn) forms a phosphorylation-dependent scaffold that recruits proteins to the mitotic centrosome, but how Cnn assembles into a scaffold is unclear. We show that scaffold assembly requires conserved leucine zipper (LZ) and Cnn-motif 2 (CM2) domains that co-assemble into a 2:2 complex in vitro. We solve the crystal structure of the LZ:CM2 complex, revealing that both proteins form helical dimers that assemble into an unusual tetramer. A slightly longer version of the LZ can form micron-scale structures with CM2, whose assembly is stimulated by Plk1 phosphorylation in vitro. Mutating individual residues that perturb LZ:CM2 tetramer assembly perturbs the formation of these micron-scale assemblies in vitro and Cnn-scaffold assembly in vivo. Thus, Cnn molecules have an intrinsic ability to form large, LZ:CM2-interaction-dependent assemblies that are critical for mitotic centrosome assembly. These studies provide the first atomic insight into a molecular interaction required for mitotic centrosome assembly.

Keywords

centrosome
centriole
PCM
Centrosomin
Cnn
Plk1
mitosis

Cited by (0)

2

These authors contributed equally

3

Present address: The Francis Crick Institute, London NW1 1AT, UK

4

Present address: Department of Zoology, University of Cambridge, Cambridge CB2 3EJ, UK

5

Lead Contact