title: Identification and Herc5-mediated ISGylation of novel target proteins.
abstract: ISG15, a protein containing two ubiquitin-like domains, is an interferon-stimulated gene product that functions in antiviral response and is conjugated to various cellular proteins (ISGylation) upon interferon stimulation. ISGylation occurs via a pathway similar to the pathway for ubiquitination that requires the sequential action of E1/E2/E3: the E1 (UBE1L), E2 (UbcH8), and E3 (Efp/Herc5) enzymes for ISGylation have been hitherto identified. In this study, we identified six novel candidate target proteins for ISGylation by a proteomic approach. Four candidate target proteins were demonstrated to be ISGylated in UBE1L- and UbcH8-dependent manners, and ISGylation of the respective target proteins was stimulated by Herc5. In addition, Herc5 was capable of binding with the respective target proteins. Thus, these results suggest that Herc5 functions as a general E3 ligase for protein ISGylation.
authors.affiliation: Department of Biochemistry, Graduate School of Pharmaceutical Sciences, Hokkaido University, Sapporo 060-0812, Japan.
authors.forename: Tomoharu
authors.initials: T
authors.lastname: Takeuchi
authors.forename: Satoshi
authors.initials: S
authors.lastname: Inoue
authors.forename: Hideyoshi
authors.initials: H
authors.lastname: Yokosawa
mesh_terms: D016207:Cytokines / Q000378:metabolism*; D019204:GTP-Binding Proteins / Q000378:metabolism; D020690:GTPase-Activating Proteins / Q000378:metabolism; D006367:HeLa Cells; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins / Q000378:metabolism*; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism; D040901:Proteomics; D020710:RGS Proteins; D014404:Tubulin / Q000378:metabolism; D014452:Ubiquitins / Q000378:metabolism*; D051759:Xeroderma Pigmentosum Group D Protein / Q000378:metabolism
chemical_list: D016207:Cytokines; D020690:GTPase-Activating Proteins; C402395:HERC5 protein, human; D047908:Intracellular Signaling Peptides and Proteins; D020710:RGS Proteins; C485898:RGS3 protein, human; D014404:Tubulin; D014452:Ubiquitins; C074034:ISG15 protein, human; D017346:Protein Serine-Threonine Kinases; C491614:STK38 protein, human; D019204:GTP-Binding Proteins; D051759:Xeroderma Pigmentosum Group D Protein; C497292:ERCC2 protein, human