Cut2 proteolysis required for sister-chromatid seperation in fission yeast.
Although mitotic cyclins are well-known substrates for ubiquitin-mediated proteolysis at the metaphase-anaphase transition, their degradation is not essential for separation of sister chromatids; several lines of evidence suggest that proteolysis of other protein(s) is required, however. Here we report the anaphase-specific proteolysis of the Schizosaccharomyces pombe Cut2 protein, which is essential for sister-chromatid separation. Cut2 is located in the nucleus, where it is concentrated along the short metaphase spindle. The rapid degradation of Cut2 at anaphase requires its amino-terminal region and the activity of Cut9 (ref. 14), a component of the 20S cyclosome/anaphase-promoting complex (APC), which is necessary for cyclin destruction. Expression of non-degradable Cut2 blocks sister-chromatid separation but not cell-cycle progression. This defect can be overcome by grafting the N terminus of cyclin B onto the truncated Cut2, demonstrating that the regulated proteolysis of Cut2 is essential for sister-chromatid separation.
Funabiki
H
H
Department of Biophysics, Faculty of Science, Kyoto University, Japan.
Yamano
H
H
Kumada
K
K
Nagao
K
K
Hunt
T
T
Yanagida
M
M
D000595:Amino Acid Sequence; D002455:Cell Division / Q000502:physiology; D002467:Cell Nucleus / Q000502:physiology; D002842:Chromatids; D005656:Fungal Proteins / Q000378:metabolism*; D008969:Molecular Sequence Data; D011994:Recombinant Proteins / Q000378:metabolism; D012568:Schizosaccharomyces / Q000166:cytology / Q000235:genetics* / Q000378:metabolism
D005656:Fungal Proteins; D011994:Recombinant Proteins