Cell Biology

Timing is Everything

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Science  21 Jul 2000:
Vol. 289, Issue 5478, pp. 361
DOI: 10.1126/science.289.5478.361a

A critical stage in cell division is the equitable partitioning of the genetic material in the nucleus. This means that division of the nucleus must occur before the cell exits mitosis and undergoes cytokinesis, or cell cleavage. How is the timing of these events coordinated? In the budding yeast Saccharomyces cerevisiae, Bardin et al. find that a key step is the transient co-compartmentalization of two proteins previously implicated in the signal transduction pathway for mitotic exit. Specifically, mitotic exit cannot be initiated unless both Tem1, a GTP binding protein, and Lte1, its putative nucleotide exchange factor, are present in the bud. Because Tem1 associates with the mitotic spindle pole body, and therefore co-localizes with Lte1 in the bud only after the nucleus enters the bud during nuclear division, this regulatory mechanism ensures that the daughter cell receives its share. — PAK

Cell102, 21 (2000).

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