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Cdk1 regulates centrosome separation by ... microtubule-associated proteins
Cdk1 regulates centrosome separation by restraining proteolysis of microtubule-associated proteins.
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In yeast, separation of duplicated spindle pole bodies (SPBs) (centrosomes in higher eukaryotes) is an indispensable step in the assembly of mitotic spindle and is triggered by severing of the bridge that connects the sister SPBs. This process requires Cdk1 (Cdc28) activation by Tyrosine 19 dephosphorylation. We show that cells that fail to activate Cdk1 are devoid of spindles due to persistently active APCCdh1, which targets microtubule-associated proteins Cin8, Kip1 and Ase1 for degradation. Tyrosine 19 dephosphorylation of Cdk1 is necessary to specifically prevent proteolysis of these proteins. Interestingly, SPB separation is dependent on the microtubule-bundling activity of Cin8 but not on its motor function. Since ectopic expression of proteolysis-resistant Cin8, Kip1 or Ase1 is sufficient for SPB separation even in the absence of Cdc28-Clb activity, we suggest that stabilization of these mechanical force-generating proteins is the predominant role of Cdc28-Clb in centrosome separation.
Crasta K, Huang P, Morgan G, Winey M, Surana U
The EMBO journal
2006-06-07 00:00
25
11
2551-63
CDC2 Protein Kinase,CDC28 Protein Kinase, S cerevisiae,Cell Cycle,Centrosome,Enzyme Activation,Microtubule-Associated Proteins,Mitotic Spindle Apparatus,Proteasome Endopeptidase Complex,Saccharomyces cerevisiae,Saccharomyces cerevisiae Proteins,Ase1 protein, S cerevisiae,Hct1 protein, S cerevisiae,KIP1 protein, S cerevisiae,Microtubule-Associated Proteins,Saccharomyces cerevisiae Proteins,CIN8 protein, S cerevisiae,CDC2 Protein Kinase,CDC28 Protein Kinase, S cerevisiae,Proteasome Endopeptidase Complex
Institute of Molecular and Cell Biology, Proteos, Singapore
EMBO J.
0261-4189
10.1038/sj.emboj.7601136
7601136
1239
True
16688214
