Separate SCFCDC4 recognition elements target Cdc6 for proteolysis in S phase and mitosis
AUTOR(ES)
Perkins, Gordon
FONTE
Oxford University Press
RESUMO
The Cdc6 DNA replication initiation factor is targeted for ubiquitin-mediated proteolysis by the E3 ubiquitin ligase SCFCDC4 from the end of G1 phase until mitosis in the budding yeast Saccharomyces cerevisiae. Here we describe a dominant-negative CDC6 mutant that, when overexpressed, arrests the cell cycle by inhibiting cyclin-dependent kinases (CDKs) and, thus, prevents passage through mitosis. This mutant protein inhibits CDKs more efficiently than wild-type Cdc6, in part because it is completely refractory to SCFCDC4-mediated proteolysis late in the cell cycle and consequently accumulates to high levels. The mutation responsible for this phenotype destroys a putative CDK phosphorylation site near the middle of the Cdc6 primary amino acid sequence. We show that this site lies within a novel Cdc4-interacting domain distinct from a Cdc4-interacting site identified previously near the N-terminus of the protein. We show that both sites can target Cdc6 for proteolysis in late G1/early S phase whilst only the newly identified site can target Cdc6 for proteolysis during mitosis.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=125267Documentos Relacionados
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