SCF E3-mediated autoubiquitination negatively regulates activity of Cdc34 E2 but plays a nonessential role in the catalytic cycle in vitro and in vivo. Mol Cell Biol 2007 Aug;27(16):5860-70
Date
06/15/2007Pubmed ID
17562869Pubmed Central ID
PMC1952114DOI
10.1128/MCB.01555-06Scopus ID
2-s2.0-34547902092 (requires institutional sign-in at Scopus site) 19 CitationsAbstract
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.
Author List
Scaglione KM, Bansal PK, Deffenbaugh AE, Kiss A, Moore JM, Korolev S, Cocklin R, Goebl M, Kitagawa K, Skowyra DMESH terms used to index this publication - Major topics in bold
Anaphase-Promoting Complex-CyclosomeBinding Sites
Catalysis
Down-Regulation
Lysine
Promoter Regions, Genetic
Protein Structure, Secondary
Recombinant Proteins
SKP Cullin F-Box Protein Ligases
Saccharomyces cerevisiae
Saccharomyces cerevisiae Proteins
Ubiquitin
Ubiquitin-Conjugating Enzymes
Ubiquitin-Protein Ligase Complexes
