SCF E3-mediated autoubiquitination negatively regulates activity of Cdc34 E2 but plays a nonessential role in the catalytic cycle in vitro and in vivo.
Journal Article (Journal Article)
One of the several still unexplained aspects of the mechanism by which the Cdc34/SCF RING-type ubiquitin ligases work is the marked stimulation of Cdc34 autoubiquitination, a phenomenon of unknown mechanism and significance. In in vitro experiments with single-lysine-containing Cdc34 mutant proteins of Saccharomyces cerevisiae, we found that the SCF-mediated stimulation of autoubiquitination is limited to specific N-terminal lysines modified via an intermolecular mechanism. In a striking contrast, SCF quenches autoubiquitination of C-terminal lysines catalyzed in an intramolecular manner. Unlike autoubiquitination of the C-terminal lysines, which has no functional consequence, autoubiquitination of the N-terminal lysines inhibits Cdc34. This autoinhibitory mechanism plays a nonessential role in the catalytic cycle, as the lysineless (K0)Cdc34(DeltaC) is indistinguishable from Cdc34(DeltaC) in ubiquitination of the prototype SCF(Cdc4) substrate Sic1 in vitro, and replacement of the CDC34 gene with either the (K0)cdc34(DeltaC) or the cdc34(DeltaC) allele in yeast has no cell cycle phenotype. We discuss the implications of these findings for the mechanism of Cdc34 function with SCF.
Full Text
Duke Authors
Cited Authors
- Scaglione, KM; Bansal, PK; Deffenbaugh, AE; Kiss, A; Moore, JM; Korolev, S; Cocklin, R; Goebl, M; Kitagawa, K; Skowyra, D
Published Date
- August 2007
Published In
Volume / Issue
- 27 / 16
Start / End Page
- 5860 - 5870
PubMed ID
- 17562869
Pubmed Central ID
- PMC1952114
International Standard Serial Number (ISSN)
- 0270-7306
Digital Object Identifier (DOI)
- 10.1128/MCB.01555-06
Language
- eng
Conference Location
- United States