The conserved protein DCN-1/Dcn1p is required for cullin neddylation in C. elegans and S. cerevisiae.
SCF-type E3 ubiquitin ligases are multi-protein complexes required for polyubiquitination and subsequent degradation of target proteins by the 26S proteasome. Cullins, together with the RING-finger protein Rbx1, form the catalytic core of the ligase, and recruit the substrate-recognition module. Cycles of covalent modification of cullins by the ubiquitin-like molecule Nedd8 (neddylation) and removal of Nedd8 by the COP9 signalosome (deneddylation) positively regulate E3 ligase activity. Here we report the identification and analysis of a widely conserved protein that is required for cullin neddylation in the nematode Caenorhabditis elegans and the yeast Saccharomyces cerevisiae. C. elegans DCN-1 and S. cerevisiae Dcn1p (defective in cullin neddylation) are characterized by a novel UBA-like ubiquitin-binding domain and a DUF298 domain of unknown function. Consistent with their requirements for neddylation, DCN-1 and Dcn1p directly bind Nedd8 and physically associate with cullins in both species. Moreover, overexpression of Dcn1p in yeast results in the accumulation of Nedd8-modified cullin Cdc53p. Both in vivo and in vitro experiments indicate that Dcn1p does not inhibit deneddylation of Cdc53p by the COP9 signalosome, but greatly increases the kinetics of the neddylation reaction.
Kurz
Thimo
T
Institute of Biochemistry, ETH Hönggerberg, 8093 Zürich, Switzerland.
Ozlü
Nurhan
N
Rudolf
Fabian
F
O'Rourke
Sean M
SM
Luke
Brian
B
Hofmann
Kay
K
Hyman
Anthony A
AA
Bowerman
Bruce
B
Peter
Matthias
M
D000251:Adenosine Triphosphatases / Q000378:metabolism; D000818:Animals; D000075686:COP9 Signalosome Complex; D017173:Caenorhabditis elegans / Q000196:embryology / Q000235:genetics / Q000378:metabolism*; D029742:Caenorhabditis elegans Proteins / Q000235:genetics / Q000378:metabolism*; D002384:Catalysis; D017124:Conserved Sequence; D044842:Cullin Proteins / Q000235:genetics / Q000378:metabolism*; D046912:Multiprotein Complexes / Q000378:metabolism; D010447:Peptide Hydrolases / Q000378:metabolism; D011485:Protein Binding; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism*; D025801:Ubiquitin / Q000378:metabolism; D044767:Ubiquitin-Protein Ligases; D014452:Ubiquitins / Q000378:metabolism*
D029742:Caenorhabditis elegans Proteins; D044842:Cullin Proteins; C502135:Dcn1 protein, S cerevisiae; D046912:Multiprotein Complexes; D029701:Saccharomyces cerevisiae Proteins; D025801:Ubiquitin; D014452:Ubiquitins; C502136:dcn-1 protein, C elegans; D044767:Ubiquitin-Protein Ligases; D010447:Peptide Hydrolases; D000075686:COP9 Signalosome Complex; D000251:Adenosine Triphosphatases; C086678:MEI-1 protein, C elegans