※ E3 activity/N-recognin/N-domain family introduction
In the N-end rule pathway, the N-degrons are recognized by N-recognins, a type of E3 ligases. Since there are various N-degrons including UBR-box, N-domain and the others, different protein domains are employed by organisms to recognize (1). The N-domain N-degron (bulky hydrophobic residues; Phe, Leu, Trp, Ile and Tyr) is recognized by a ~80-residue N-domain, which shows sequential, structural and functional similarities with the 106-residue Escherichia coli ClpS, a bacterial N-recognin (2). N-domains are usually found in the downstream from the UBR-boxes. Here we defined the N-domain family as the N- recognins contain the N-domain.
1. Sriram, S.M., Kim, B.Y. and Kwon, Y.T. (2011). The N-end rule pathway: emerging functions and molecular principles of substrate recognition. Nat. Rev. Mol. Cell Biol., 12, 735-747. PMID: 22016057
2. Tasaki, T., Zakrzewska, A., Dudgeon, D.D., Jiang, Y., Lazo, J.S. and Kwon, Y.T. (2009). The substrate recognition domains of the N-end rule pathway. J. Biol. Chem., 284, 1884-1895. PMID: 19008229