Analysis of activator-binding sites on the APC/C supports a cooperative substrate-binding mechanism.
Mol Cell
; 34(1): 68-80, 2009 Apr 10.
Article
em En
| MEDLINE
| ID: mdl-19362536
ABSTRACT
The anaphase-promoting complex or cyclosome (APC/C) is a ubiquitin ligase essential for the completion of mitosis in all eukaryotic cells. Substrates are recruited to the APC/C by activator proteins (Cdc20 or Cdh1), but it is not known where substrates are bound during catalysis. We explored this problem by analyzing mutations in the tetratricopeptide-repeat-containing APC/C subunits. We identified residues in Cdc23 and Cdc27 that are required for APC/C binding to Cdc20 and Cdh1 and for APC/C function in vivo. Mutation of these sites increased the rate of activator dissociation from the APC/C but did not affect reaction processivity, suggesting that the mutations have little effect on substrate dissociation from the active site. Further studies revealed that activator dissociation from the APC/C is inhibited by substrate, and that substrates are not bound solely to activator during catalysis but interact bivalently with an additional binding site on the APC/C core.
Texto completo:
1
Base de dados:
MEDLINE
Assunto principal:
Saccharomyces cerevisiae
/
Complexos Ubiquitina-Proteína Ligase
Idioma:
En
Revista:
Mol Cell
Assunto da revista:
BIOLOGIA MOLECULAR
Ano de publicação:
2009
Tipo de documento:
Article
País de afiliação:
Estados Unidos