The ch-TOG/XMAP215 protein is essential for spindle pole organization in human somatic cells
Abstract
The ch-TOG/XMAP215 family of proteins bind directly to microtubules and appear to play an essential role in stabilizing spindle microtubules. These proteins stabilize microtubules mainly by influencing microtubule plus-end dynamics, yet, in vivo, they are all strongly concentrated at spindle poles, where the minus ends of the microtubules are concentrated. In Drosophila embryos, the centrosomal protein D-TACC is required to efficiently recruit ch-TOG/Msps to centrosomes. In humans, ch-TOG and the three known TACC proteins have been implicated in cancer, but their functions are unknown. Here we extensively depleted TACC3 and ch-TOG from HeLa cells using RNA interference. In TACC3-depleted cells, spindles are well organized, but microtubules are partially destabilized and ch-TOG is no longer concentrated on spindle microtubules. In ch-TOG-depleted cells, relatively robust spindles form, but the spindles are highly disorganized. Thus, in human somatic cells, ch-TOG appears to play a major role in organizing spindle poles, and a more minor role in stabilizing spindle microtubules that is, at least in part, mediated via an interaction with TACC3.
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Footnotes
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↵4 Present address: Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
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↵5 Corresponding author.
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E-MAIL j.raff{at}welc.cam.ac.uk; FAX 44-1223-334089.
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Article and publication are at http://www.genesdev.org/cgi/doi/10.1101/gad.245603.
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- Received August 7, 2002.
- Accepted November 4, 2002.
- Cold Spring Harbor Laboratory Press