Kaposi sarcoma-associated herpesvirus vIRF-3 protein binds to F-box of Skp2 protein and acts as a regulator of c-Myc protein function and stability

J Biol Chem. 2012 May 11;287(20):16199-208. doi: 10.1074/jbc.M111.335216. Epub 2012 Mar 27.

Abstract

The Kaposi sarcoma-associated herpesvirus (KSHV) has been linked to Kaposi sarcoma, body cavity-based lymphoma, and Castleman disease. vIRF-3 is a KSHV latent gene that is critical for proliferation of KSHV-positive lymphoid cells. Furthermore, vIRF-3 contributes to KSHV-associated pathogenesis by stimulating c-Myc transcription activity. Here we show that vIRF-3 can associate with Skp2, a key component of the SCF(skp2) ubiquitin ligase complex. Skp2 is a transcriptional co-factor for c-Myc that was shown to regulate the stability of c-Myc protein as well as c-Myc-dependent transcription. In this study, we show that vIRF-3 binds to the F-box of Skp2 and recruits it to c-Myc-regulated promoters to activate c-Myc-dependent transcription. Additionally, cells overexpressing vIRF-3 exhibit higher levels of c-Myc ubiquitylation, suggesting that ubiquitylation is necessary for c-Myc-mediated transcription. Moreover, vIRF-3 can stabilize the c-Myc protein by increasing its half-life. Collectively, these results indicate that vIRF-3 can effectively manipulate c-Myc stability and function and thus contribute to c-Myc-induced KSHV-associated lymphomagenesis.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Castleman Disease / genetics
  • Castleman Disease / metabolism*
  • Castleman Disease / virology
  • HEK293 Cells
  • HeLa Cells
  • Herpesvirus 8, Human / genetics
  • Herpesvirus 8, Human / metabolism*
  • Humans
  • Interferon Regulatory Factors / genetics
  • Interferon Regulatory Factors / metabolism*
  • Lymphocytes / metabolism*
  • Lymphocytes / virology
  • Protein Binding
  • Protein Stability
  • Proto-Oncogene Proteins c-myc / genetics
  • Proto-Oncogene Proteins c-myc / metabolism*
  • S-Phase Kinase-Associated Proteins / genetics
  • S-Phase Kinase-Associated Proteins / metabolism*
  • Transcription, Genetic / genetics
  • Ubiquitination / genetics
  • Viral Proteins / genetics
  • Viral Proteins / metabolism*

Substances

  • Interferon Regulatory Factors
  • MYC protein, human
  • Proto-Oncogene Proteins c-myc
  • S-Phase Kinase-Associated Proteins
  • Viral Proteins
  • viral interferon regulatory factors