The high-risk human papillomavirus type 16 E6 counters the GAP function of E6TP1 toward small Rap G proteins

Latika Singh, Qingshen Gao, Ajay Kumar, Takaya Gotoh, David E. Wazer, Hamid Band, Larry A. Feig, Vimla Band

Research output: Contribution to journalArticle

39 Scopus citations

Abstract

We have recently identified E6TP1 (E6-targeted protein 1) as a novel high-risk human papillomavirus type 16 (HPV16) E6-binding protein. Importantly, mutational analysis of E6 revealed a strong correlation between the transforming activity and its abilities to bind and target E6TP1 for ubiquitin-mediated degradation. As a region within E6TP1 has high homology with GAP domains of known and putative Rap GTPase-activating proteins (GAPs), these results raised the possibility that HPV E6 may alter the Rap small-G-protein signaling pathway. Using two different approaches, we now demonstrate that human E6TP1 exhibits GAP activity for Rap1 and Rap2, confirming recent findings that a closely related rat homologue exhibits Rap-specific GAP activity. Using mutational analysis, we localize the GAP activity to residues 240 to 945 of E6TP1. Significantly, we demonstrate that coexpression of HPV16 E6, by promoting the degradation of E6TP1, enhances the GTP loading of Rap. These results support a role of Rap small-G-protein pathway in E6-mediated oncogenesis.

Original languageEnglish (US)
Pages (from-to)1614-1620
Number of pages7
JournalJournal of virology
Volume77
Issue number2
DOIs
StatePublished - Jan 1 2003

ASJC Scopus subject areas

  • Microbiology
  • Immunology
  • Insect Science
  • Virology

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