title: Newly translated proteins are substrates for ubiquitin, ISG15, and FAT10.
abstract: The ubiquitin-like modifier, FAT10, is involved in proteasomal degradation and antigen processing. As ubiquitin and the ubiquitin-like modifier, ISG15, cotranslationally modify proteins, we investigated whether FAT10 could also be conjugated to newly synthesized proteins. Indeed, we found that nascent proteins are modified with FAT10, but not with the same preference for newly synthesized proteins as observed for ISG15. Our data show that puromycin-labeled polypeptides are strongly modified by ISG15 and less intensely by ubiquitin and FAT10. Nevertheless, conjugates of all three modifiers copurify with ribosomes. Taken together, we show that unlike ISG15, ubiquitin and FAT10 are conjugated to a similar degree to newly translated and pre-existing proteins.
authors.affiliation: Division of Immunology, Department of Biology, University of Konstanz, Germany.
authors.forename: Valentina
authors.initials: V
authors.lastname: Spinnenhirn
authors.affiliation: Division of Immunology, Department of Biology, University of Konstanz, Germany.
authors.forename: Annegret
authors.initials: A
authors.lastname: Bitzer
authors.affiliation: Biotechnology Institute Thurgau at the, University of Konstanz, Kreuzlingen, Switzerland.
authors.forename: Annette
authors.initials: A
authors.lastname: Aichem
authors.affiliation: Division of Immunology, Department of Biology, University of Konstanz, Germany.|Biotechnology Institute Thurgau at the, University of Konstanz, Kreuzlingen, Switzerland.
authors.forename: Marcus
authors.initials: M
authors.lastname: Groettrup
mesh_terms: D016207:Cytokines / Q000378:metabolism*; D057809:HEK293 Cells; D006801:Humans; D014176:Protein Biosynthesis; D011691:Puromycin / Q000378:metabolism; D012270:Ribosomes / Q000378:metabolism; D013379:Substrate Specificity; D025801:Ubiquitin / Q000378:metabolism*; D014452:Ubiquitins / Q000378:metabolism*
chemical_list: D016207:Cytokines; C109184:UBD protein, human; D025801:Ubiquitin; D014452:Ubiquitins; D011691:Puromycin; C074034:ISG15 protein, human
keywords: FAT10; ISG15; cotranslational conjugation; defective ribosomal products; newly translated proteins; ubiquitin