Research NewsCELL CYCLE

Cell Division Gatekeepers Identified

Science  23 Jan 1998:
Vol. 279, Issue 5350, pp. 477-478
DOI: 10.1126/science.279.5350.477

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Summary

A convergence of research in yeast genetics, cell biology, and biochemistry is suggesting an answer to the question of how the dividing cell keeps track of its chromosomes: Molecular nannies called kinetochores keep a sharp eye on them so that the cell doesn't divide before they all attach to the fibers of the mitotic spindle and line up in the middle of the cell. Although the kinetochores, specialized bits of DNA and protein, were already known to have a mechanical role in cell division, the new work, some of which was presented last month at the annual meeting of the American Society for Cell Biology in Washington, suggests that they play an active role in controlling cell division. Kinetochores that have not yet attached to the spindle make sure that the chromosomes are not pulled apart prematurely by releasing a protein signal that works with other proteins to put the brakes on cell division. But when the spindle attaches, a protein involved in that linkage somehow disables the wait signal, thereby releasing the brakes on mitosis. The work is intriguing because it adds to recent evidence that the cytoskeleton doesn't just carry out orders issued elsewhere in the cell but instead is an integral part of the cell's command structure. In this case, the work links the cytoskeleton to the continuation of the cell cycle.