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E2-C, a cyclin-selective ubiquitin carrier protein required for the destruction of mitotic cyclins.

ABSTRACT: Ubiquitin-dependent proteolysis of the mitotic cyclins A and B is required for the completion of mitosis and entry into the next cell cycle. This process is catalyzed by the cyclosome, an approximately 22S particle that contains a cyclin-selective ubiquitin ligase activity, E3-C, that requires a cyclin-selective ubiquitin carrier protein (UBC) E2-C. Here we report the purification and cloning of E2-C from clam oocytes. The deduced amino acid sequence of E2-C indicates that it is a new UBC family member. Bacterially expressed recombinant E2-C is active in in vitro cyclin ubiquitination assays, where it exhibits the same substrate specificities seen with native E2-C. These results demonstrate that E2-C is not a homolog of UBC4 or UBC9, proteins previously suggested to be involved in cyclin ubiquitination, but is a new UBC family member with unique properties.

SUBMITTER: Aristarkhov A

PROVIDER: S-EPMC39529 | biostudies-other | 1996 Apr

REPOSITORIES: biostudies-other

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E2-C, a cyclin-selective ubiquitin carrier protein required for the destruction of mitotic cyclins.

Aristarkhov A A Eytan E E Moghe A A Admon A A Hershko A A Ruderman J V JV

Proceedings of the National Academy of Sciences of the United States of America 19960401 9

Ubiquitin-dependent proteolysis of the mitotic cyclins A and B is required for the completion of mitosis and entry into the next cell cycle. This process is catalyzed by the cyclosome, an approximately 22S particle that contains a cyclin-selective ubiquitin ligase activity, E3-C, that requires a cyclin-selective ubiquitin carrier protein (UBC) E2-C. Here we report the purification and cloning of E2-C from clam oocytes. The deduced amino acid sequence of E2-C indicates that it is a new UBC family ...[more]

PMID: 8633058

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