title: Two novel ubiquitin-fold modifier 1 (Ufm1)-specific proteases, UfSP1 and UfSP2.
abstract: Ubiquitin-fold modifier 1 (Ufm1) is a recently identified new ubiquitin-like protein, whose tertiary structure displays a striking resemblance to ubiquitin. Similar to ubiquitin, it has a Gly residue conserved across species at the C-terminal region with extensions of various amino acid sequences that need to be processed in vivo prior to conjugation to target proteins. Here we report the isolation, cloning, and characterization of two novel mouse Ufm1-specific proteases, named UfSP1 and UfSP2. UfSP1 and UfSP2 are composed of 217 and 461 amino acids, respectively, and they have no sequence homology with previously known proteases. UfSP2 is present in most, if not all, of multicellular organisms including plant, nematode, fly, and mammal, whereas UfSP1 could not be found in plant and nematode upon data base search. UfSP1 and UfSP2 cleaved the C-terminal extension of Ufm1 but not that of ubiquitin or other ubiquitin-like proteins, such as SUMO-1 and ISG15. Both were also capable of releasing Ufm1 from Ufm1-conjugated cellular proteins. They were sensitive to inhibition by sulfhydryl-blocking agents, such as N-ethylmaleimide, and their active site Cys could be labeled with Ufm1-vinylmethylester. Moreover, replacement of the conserved Cys residue by Ser resulted in a complete loss of the UfSP1 and UfSP2 activities. These results indicate that UfSP1 and UfSP2 are novel thiol proteases that specifically process the C terminus of Ufm1.
authors.affiliation: School of Biological Sciences, Seoul National University, Seoul 151-742, Korea.
authors.forename: Sung Hwan
authors.initials: SH
authors.lastname: Kang
authors.forename: Gi Ryang
authors.initials: GR
authors.lastname: Kim
authors.forename: Minu
authors.initials: M
authors.lastname: Seong
authors.forename: Sung Hee
authors.initials: SH
authors.lastname: Baek
authors.forename: Jae Hong
authors.initials: JH
authors.lastname: Seol
authors.forename: Ok Sun
authors.initials: OS
authors.lastname: Bang
authors.forename: Huib
authors.initials: H
authors.lastname: Ovaa
authors.forename: Kanako
authors.initials: K
authors.lastname: Tatsumi
authors.forename: Masaaki
authors.initials: M
authors.lastname: Komatsu
authors.forename: Keiji
authors.initials: K
authors.lastname: Tanaka
authors.forename: Chin Ha
authors.initials: CH
authors.lastname: Chung
mesh_terms: D019943:Amino Acid Substitution; D000818:Animals; D001665:Binding Sites / Q000235:genetics; D003546:Cysteine Endopeptidases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D016207:Cytokines / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D006801:Humans; D051379:Mice; D010447:Peptide Hydrolases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D011506:Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D025842:SUMO-1 Protein / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D014452:Ubiquitins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism
chemical_list: D016207:Cytokines; C489550:G1p2 protein, mouse; D011506:Proteins; D025842:SUMO-1 Protein; D014452:Ubiquitins; C513664:Ufm1 protein, mouse; D010447:Peptide Hydrolases; D003546:Cysteine Endopeptidases; C518815:UfSP1 protein, mouse; C518816:UfSP2 protein, mouse