A TACC3/ch-TOG/clathrin complex stabilises kinetochore fibres by inter-microtubule bridging

paper

mitosis

joint first author

Author

Booth DG, Hood FE, Prior IA, Royle SJ.

Doi

https://doi.org/10.1038/emboj.2011.15

Citation

Booth, D.G., Hood, F.E., Prior, I.A., and Royle, S.J. (2011). A TACC3/ch-TOG/clathrin complex stabilises kinetochore fibres by inter-microtubule bridging. EMBO J 30, 906–919.

Abstract

Kinetochore fibres (K-fibres) of the spindle apparatus move chromosomes during mitosis. These fibres are discrete bundles of parallel microtubules (MTs) that are crosslinked by inter-MT ‘bridges’ that are thought to improve fibre stability during chromosomal movement. The identity of these bridges is unknown. Clathrin is a multimeric protein that has been shown to stabilise K-fibres during early mitosis by a mechanism independent of its role in membrane trafficking. In this study, we show that clathrin at the mitotic spindle is in a transforming acidic colied-coil protein 3 (TACC3)/colonic, hepatic tumour overexpressed gene (ch-TOG)/clathrin complex. The complex is anchored to the spindle by TACC3 and ch-TOG. Ultrastructural analysis of clathrin-depleted K-fibres revealed a selective loss of a population of short inter-MT bridges and a general loss of MTs. A similar loss of short inter-MT bridges was observed in TACC3-depleted K-fibres. Finally, immunogold labelling confirmed that inter-MT bridges in K-fibres contain clathrin. Our results suggest that the TACC3/ch-TOG/clathrin complex is an inter-MT bridge that stabilises K-fibres by physical crosslinking and by reducing rates of MT catastrophe.