A mechanism for coupling exit from mitosis to partitioning of the nucleus.
Exit from mitosis must not occur prior to partitioning of chromosomes between daughter cells. We find that the GTP binding protein Tem1, a regulator of mitotic exit, is present on the spindle pole body that migrates into the bud during S phase and mitosis. Tem1's exchange factor, Lte1, localizes to the bud. Thus, Tem1 and Lte1 are present in the same cellular compartment (the bud) only after the nucleus enters the bud during nuclear division. We also find that the presence of Tem1 and Lte1 in the bud is required for mitotic exit. Our results suggest that the spatial segregation of Tem1 and Lte1 ensures that exit from mitosis only occurs after the genetic material is partitioned between mother and daughter cell.
Center for Cancer Research, Massachusetts Institute of Technology, Cambridge 02139, USA.
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Bardin
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Visintin
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D002453:Cell Cycle; D018797:Cell Cycle Proteins / Q000378:metabolism; D002467:Cell Nucleus / Q000378:metabolism / Q000502:physiology*; D005656:Fungal Proteins / Q000378:metabolism / Q000502:physiology*; D016193:G1 Phase; D019204:GTP-Binding Proteins / Q000378:metabolism; D020662:Guanine Nucleotide Exchange Factors; D008938:Mitosis / Q000502:physiology*; D020559:Monomeric GTP-Binding Proteins / Q000502:physiology*; D017027:Protein Tyrosine Phosphatases; D029701:Saccharomyces cerevisiae Proteins; D008941:Spindle Apparatus / Q000378:metabolism / Q000502:physiology*
C070351:BUB2 protein, S cerevisiae; C074860:CDC14 protein, S cerevisiae; C082279:CDC15 protein; D018797:Cell Cycle Proteins; D005656:Fungal Proteins; D020662:Guanine Nucleotide Exchange Factors; C089357:LTE1 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; C089965:TEM1 protein, S cerevisiae; D017027:Protein Tyrosine Phosphatases; D019204:GTP-Binding Proteins; D020559:Monomeric GTP-Binding Proteins