Covalent ISG15 conjugation to CHIP promotes its ubiquitin E3 ligase activity and inhibits lung cancer cell growth in response to type i interferon article

Lang Yoo, A. Rum Yoon, Chae Ok Yun, Kwang Chul Chung

Research output: Contribution to journalArticle

12 Citations (Scopus)

Abstract

The carboxyl terminus of Hsp70-interacting protein (CHIP) acts as a ubiquitin E3 ligase and a link between the chaperones Hsp70/90 and the proteasome system, playing a vital role in maintaining protein homeostasis. CHIP regulates a number of proteins involved in a myriad of physiological and pathological processes, but the underlying mechanism of action via posttranslational modification has not been extensively explored. In this study, we investigated a novel modulatory mode of CHIP and its effect on CHIP enzymatic activity. ISG15, an ubiquitin-like modifier, is induced by type I interferon (IFN) stimulation and can be conjugated to target proteins (ISGylation). Here we demonstrated that CHIP may be a novel target of ISGylation in HEK293 cells stimulated with type I IFN. We also found that Lys143/144/145 and Lys287 residues in CHIP are important for and target residues of ISGylation. Moreover, ISGylation promotes the E3 ubiquitin ligase activity of CHIP, subsequently causing a decrease in levels of oncogenic c-Myc, one of its many ubiquitination targets, in A549 lung cancer cells and inhibiting A549 cell and tumor growth. In conclusion, the present study demonstrates that covalent ISG15 conjugation produces a novel CHIP regulatory mode that enhances the tumor-suppressive activity of CHIP, thereby contributing to the antitumor effect of type I IFN.

Original languageEnglish
Article number97
JournalCell Death and Disease
Volume9
Issue number2
DOIs
Publication statusPublished - 2018 Feb 1

All Science Journal Classification (ASJC) codes

  • Immunology
  • Cellular and Molecular Neuroscience
  • Cell Biology
  • Cancer Research

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