The Cellular Isopeptidase T Deubiquitinating Enzyme Regulates Kaposi's Sarcoma-Associated Herpesvirus K7 Degradation.
- Resource Type
- Article
- Authors
- Xiao, Jun; Wu, Hui; Peng, Lingzhi; Chi, Mengdie; Feng, Hao
- Source
- Pharmaceutical Research. Mar2015, Vol. 32 Issue 3, p749-761. 13p.
- Subject
- *KAPOSI'S sarcoma
*PEPTIDASE
*HERPESVIRUS diseases
*PROTEOMICS
*IMMUNOFLUORESCENCE
*PROTEIN stability
*UBIQUITIN
*THERAPEUTICS
- Language
- ISSN
- 0724-8741
Purpose: To understand the regulated degradation of KSHV K7. Methods: Proteomic screen and immunofluoresence microscopy identified that K7 recruits polyubiquitin chains to membrane fractions; IP and GST pulldown verified the interaction between K7 and Iso T1; Protein stability assay and RQ-PCR demonstrated Iso T1 facilitates K7 degradation. Results: The K7-containing membrane fraction contains a higher level of deubiquitinating (DUB) activity and K7 interacts with a cellular DUB, isopeptidase T1 (Iso T1). Mutational analyses revealed that the ubiquitin-associated domains of Iso T1 are necessary and sufficient to bind K7. Confocal microscopy and fractionation analyses indicated that K7 increases the membrane-associated Iso T1. Furthermore, the knockdown of IsoT1 by shRNA-mediated silencing greatly increased K7 ubiquitination even when proteasome activity was inhibited by lactacystin. Conclusions: IsoT1 disassembles of free ubiquitin chains to facilitate K7 degradation. [ABSTRACT FROM AUTHOR]