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

作者：Booth Daniel G; Hood Fiona E; Prior Ian A; Royle Stephen J^*

来源：The EMBO Journal, 2011, 30(5): 906-919.

DOI：10.1038/emboj.2011.15

• clathrin
• crosslinking
• kinetochore fibre
• microtubule
• mitotic spindle

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. The EMBO Journal (2011) 30, 906-919. doi: 10.1038/emboj.2011.15; Published online 4 February 2011

• 出版日期2011-3-2