Three different cullins are neddylated in Aspergillus nidulans

Marcia Kress, Oliver Valerius, Gerhard Braus

Author address: 

Institute of Microbiology and Genetics, Georg August University, Göttingen, Germany


The NEDD8/RubA protein belongs to the Ubiquitin-like protein group and its conjugating process is mechanistically similar to ubiquitination. In this conjugating process NEDD8/Rub1 is activated by E1 enzyme (Uba3/Ula1) and conjugated by E2 enzyme (Ubc12). The known substrates of the NEDD8, in a process called neddylation, are the Cullin family proteins, and the activity of COP9 Signalosome Complex is required for the de-neddylation of the neddylated cullins. The neddylation pathway is essential in mammalian cells, C.elegans and fission yeast. NEDD8 is synthesized in a precursor form with a C-terminal extension peptide that ranges from 1 to 8 aminoacids depending on the species. These de novo synthesized precursors are accurately cleaved at the C-terminal site to form the mature NEDD8. The exposure of the C-terminal glycine (Gly) residue of NEDD8 is essential for its subsequent conjugation reaction. In this work, the filamentous ascomycete A. nidulans was used as a model organism for the identification of RubA-interacting proteins and RubA-substrates. The phenotype of the 916;rubA null allele was defined and has been confirmed by Heterokaryon rescue technique that rubA gene is essential in A. nidulans. Through the protein complex purification of TAP-tag::rubA and TAP-tag::cDNArubA strains of A. nidulans, some expected proteins were isolated and identified by Mass Spectrometry analysis. Among the detected proteins by Mass Spectrometry are all cullins described until now for A. nidulans (CulA, C and D), two E1 enzymes already described in the literature as partners of Nedd8/Rub1 (UlaA and UbaC), as well RubA and other proteins as ribosomal proteins, transcription facto protein, chaperonine and F-box proteins.

abstract No: 


Full conference title: 

    • ECFG 9th (2008)