Simian virus 40 large T antigen's association with the CUL7 SCF complex contributes to cellular transformation

Jocelyn S. Kasper, Hiroshi Kuwabara, Takehiro Arai, Syed Hamid Ali, James A. DeCaprio

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44 Citations (Scopus)


Simian virus 40 large T antigen (T Ag) is capable of immortalizing and transforming rodent cells. The transforming activity of T Ag is due in large part to perturbation of the tumor suppressor proteins p53 and the retinoblastoma (pRB) family members. Inactivation of these tumor suppressors may not be sufficient for T Ag-mediated cellular transformation. It has been shown that T Ag associates with an SCF-like complex that contains a member of the cullin family of E3 ubiquitin ligases, CUL7, as well as SKP1, RBX1, and an F-box protein, FBXW8. We identified T Ag residues 69 to 83 as required for T Ag binding to the CUL7 complex. We demonstrate that Δ69-83 T Ag, while it lost its ability to associate with CUL7, retained binding to p53 and pRB family members. In the presence of CUL7, wild-type (WT) T Ag but not Δ69-83 T Ag was able to induce proliferation of mouse embryo fibroblasts, an indication of cellular transformation. In contrast, WT and Δ69-83 T Ag enabled mouse embryo fibroblasts to proliferate to similarly high densities in the absence of CUL7. Our data suggest that, in addition to p53 and the pRB family members, T Ag serves to bind to and inactivate the growth-suppressing properties of CUL7. In addition, these results imply that, at least in the presence of T Ag, CUL7 may function as a tumor suppressor.

Original languageEnglish
Pages (from-to)11685-11692
Number of pages8
JournalJournal of Virology
Issue number18
Publication statusPublished - Sep 2005

ASJC Scopus subject areas

  • Microbiology
  • Immunology
  • Insect Science
  • Virology

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