Sari F, et al. (2007) A process independent of the anaphase-promoting complex contributes to instability of the yeast S phase cyclin Clb5. J Biol Chem 282(36):26614-22
Abstract: Proteolytic destruction of many cyclins is induced by a multi-subunit ubiquitin ligase termed the anaphase promoting complex/cyclosome (APC/C). In the budding yeast Saccharomyces cerevisiae, the S phase cyclin Clb5 and the mitotic cyclins Clb1-4 are known as substrates of this complex. The relevance of APC/C in proteolysis of Clb5 is still under debate. Importantly, a deletion of the Clb5 destruction box has little influence on cell cycle progression. To understand Clb5 degradation in more detail, we applied in vivo pulse labeling to determine the half-life of Clb5 at different cell cycle stages and in the presence or absence of APC/C activity. Clb5 is significantly unstable, with a half-life of approximately 8-10 min, at cell cycle periods when APC/C is inactive and in mutants impaired in APC/C function. A Clb5 version lacking its cyclin destruction box is similarly unstable. The half-life of Clb5 is further decreased in a destruction box-dependent manner to 3-5 min in mitotic or G(1) cells with active APC/C. Clb5 instability is highly dependent on the function of the proteasome. We conclude that Clb5 proteolysis involves two different modes for targeting of Clb5 to the proteasome, an APC/C-dependent and an APC/C-independent mechanism. These different modes apparently have overlapping functions in restricting Clb5 levels in a normal cell cycle, but APC/C function is essential in the presence of abnormally high Clb5 levels.
|Status: Published||Type: Journal Article | Research Support, Non-U.S. Gov't||PubMed ID: 17620341|
Topics addressed in this paper
Number of different genes curated to this paper: 13
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|Topics||Genes (#1 - 10 )|
|Cell Cycle Phase Involved|
|Protein Physical Properties|
|Protein Sequence Features|
|Topics||Genes (#11 - 13 )|