期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：2002
卷号：99
期号：12
页码：7889-7894
DOI：10.1073/pnas.122246999
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：Infected cell protein 0 (ICP0) of herpes simplex virus-1 is a 775-aa residue multifunctional protein that acts as a promiscuous transactivator linked to the degradation of several proteins. ICP0 is the only protein known which encodes two physically separated E3 ubiquitin (Ub) ligase domains, one, designated herpes virus Ub ligase 1 (HUL-1) located in a domain encoded in exon 3 and one designated herpes virus Ub ligase 2 (HUL-2) associated with the really interesting new gene (RING) finger domain encoded by exon 2. We report the following: (i) ICP0 residues 543-680 are sufficient for HUL-1 E3 activity and necessary determinants are encoded between residues 616 and 680. (ii) In substrate independent in vitro ubiquitylation reactions, a chimeric protein containing the HUL-1 domain promotes the ubiquitylation of itself and the ubiquitin conjugating enzyme (E2) cdc34 and interacts with cdc34. (iii) The mechanism of HUL-1 E3 function does not involve formation of a thioester between the HUL-1 domain and Ub. (iv) Residues 621-625 are essential for in vitro HUL-1 E3 activity and interaction between the HUL-1 domain and cdc34, suggesting that this interaction is required for HUL-1 E3 function.
