Assembly of different length of polyubiquitins on the catalytic cysteine of E2 enzymes without E3 ligase; a novel application of non-reduced/reduced 2-dimensional electrophoresis

作者：Shin Dong Yeon; Lee Hyunju; Park Eun Sil; Yoo Yung Joon^*

来源：FEBS LETTERS, 2011, 585(24): 3959-3963.

DOI：10.1016/j.febslet.2011.11.002

• Ube2K/E2-25K
• Cdc34/Ube2R1
• Ube2g2/Ubc7
• UbcH10/Ube2C
• E3-independent ubiquitination

In this study using non-reduced/reduced 2-dimensional electrophoresis (NR/R-2DE), we clearly demonstrated that E3-independent ubiquitination by Ube2K produced not only unanchored but also Ube2K-linked polyubiquitins through thioester and isopeptide bonds. E3-independent assembly of polyubiquitins on the catalytic cysteine of Ube2K strongly supports the possibility of 'en bloc transfer' for polyubiquitination. From the same analyses of E3-independent ubiquitination products by other E2s, we also found that different lengths of polyubiquitins were linked to different E2s through thioester bond; longer chains by Cdc34 like Ube2K, short chains by Ube2g2, and mono-ubiquitin by UbcH10. Our results suggest that E2s possess the different intrinsic catalytic activities for polyubiquitination.

• 出版日期2011-12-15