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A TACC3/ch‐TOG/clathrin complex stabilises kinetochore fibres by inter‐microtubule bridging
Author(s) -
Booth Daniel G,
Hood Fiona E,
Prior Ian A,
Royle Stephen J
Publication year - 2011
Publication title -
the embo journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 7.484
H-Index - 392
eISSN - 1460-2075
pISSN - 0261-4189
DOI - 10.1038/emboj.2011.15
Subject(s) - clathrin , biology , mitosis , microtubule , spindle apparatus , microbiology and biotechnology , kinetochore , population , phragmoplast , biophysics , cell division , chromosome , vesicle , biochemistry , membrane , gene , cell , demography , sociology
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.