The different sub-populations of microtubules of the mitotic spindle play different roles. Astral microtubules interact with the cell cortex, and this contact is important for regulating the position of the cleavage furrow that begins cytokinesis, the splitting of the cell into two daughter cells. A recent paper shows that after treatment to elongate astral microtubules, the mitotic spindle rocked severely. This rocking is due to a change in the location of the actin cytoskeleton at the cortex prior to cytokinesis. Image above shows mitotic cells with (right) or without (left) the treatment to elongate astral microtubules, and higher magnified regions underneath.
Reference: Kathleen E. Rankin and Linda Wordeman, 2010. Originally published in Journal of Cell Bioloy. doi: 10.1083/jcb.201004017. Paper can be found here. Check out the authors’ cover image for the same issue of JCB here.