Cell Biology

Spindle Positioning

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Science  28 Mar 2003:
Vol. 299, Issue 5615, pp. 1949
DOI: 10.1126/science.299.5615.1949c

The molecular motor dynein helps to position the mitotic spindle during the later stages of cell division in budding yeast. At anaphase, when chromosomes are partitioned between the mother cell and the bud, dynein is important in placing the mitotic spindle across the bud neck. This process involves the recruitment of astral microtubules and the association of dynein with the cell cortex. Sheeman et al. detail how dynein is delivered to the cortex of the cell on the tips of polymerizing astral microtubules and then activated via an interaction with the Num1 protein. Num1 is thought to act as an anchor for dynein at the cortex and also appears to enhance the processivity of the dynein motor. Mutations of cargo-binding proteins (Bik1) interfere with the loading of dynein onto astral microtubules, and mutations that interfere with Num1 cause the accumulation of dynein on the plus ends of astral microtubules during anaphase. — SMH

Curr. Biol.13, 364 (2003).

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