The ubiquitin fold modifier 1 (Ufm1) is the most recently discovered ubiquitin-like modifier whose conjugation (ufmylation) system is conserved in multicellular organisms. Ufm1 is known to covalently attach with cellular protein(s) via a specific E1-activating enzyme (Uba5), an E2-conjugating enzyme (Ufc1), and a E3-ligating enzyme [1].

1: A novel type of E3 ligase for the Ufm1 conjugation system. Tatsumi K, Sou YS, Tada N, Nakamura E, Iemura S, Natsume T, Kang SH, Chung CH, Kasahara M, Kominami E, Yamamoto M, Tanaka K, Komatsu M; J Biol Chem. 2010;285:5417-5427. PMID:20018847