Chromosome alignment on the spindle (top) is lost if Cdc42 is inactivated (bottom).

Narumiya/Macmillan

Results from Shingo Yasuda, Shuh Narumiya (Kyoto University, Kyoto, Japan), and colleagues reveal microtubules at the cell cortex, are also needed for microtubule–kinetochore attachments, thus uniting two previously distant fields of study.

Rho GTPases are needed during cytokinesis, when Rho helps build a contractile actin ring. Another Rho family member, Cdc42, is now shown to be required for nuclear division. Without its activity, chromosomes failed to make bipolar attachments. Some chromosomes were attached to one pole or the other, suggesting that correction of monoorientation, rather than capture itself, is controlled by the GTPase.

Rho GTPases control both cortical and kinetochore capture by activating a formin homologue, mDia. At the cortex in yeast, an mDia1 homologue polymerizes long actin tracks that EB1-bound microtubules use to find their way to the cortex. At...

The Rockefeller University Press
2004
The Rockefeller University Press
2004
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