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Functionally distinct monomers and trimers produced by a viral oncoprotein

S-H Chung1, R S Weiss, K K Frese

  • 1Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, TX 77030, USA.

Oncogene
|September 11, 2007
PubMed

Insights

Adenovirus E4-ORF1 oncoprotein monomers and trimers bind different proteins, leading to distinct cellular functions. This oligomerization-dependent mechanism offers a novel strategy for protein regulation in tumorigenesis.

Area of Science:

  • Molecular biology
  • Virology
  • Cellular biology

Background:

  • Protein oligomerization is a key mechanism for regulating protein activity.
  • Independent functions of protein subunits and oligomers are rarely reported.
  • Adenovirus E4-ORF1 oncoprotein drives tumorigenesis by interacting with cellular PDZ proteins.

Purpose of the Study:

  • To investigate the functional roles of adenovirus E4-ORF1 oncoprotein in its monomeric and trimeric states.
  • To identify the specific cellular PDZ proteins that interact with each oligomeric state.
  • To elucidate the functional consequences of these distinct interactions.

Main Methods:

  • Cellular expression and analysis of adenovirus E4-ORF1 oncoprotein.
  • Co-immunoprecipitation assays to identify binding partners.
  • Confocal microscopy to assess protein localization.

Main Results:

  • Adenovirus E4-ORF1 exists as both monomers and trimers within cells.
  • E4-ORF1 monomers sequester MUPP1, MAGI-1, and ZO-2 into insoluble complexes.
  • E4-ORF1 trimers bind Dlg1 and promote its plasma membrane translocation.

Conclusions:

  • The oligomerization state of E4-ORF1 dictates its binding to distinct PDZ proteins.
  • This oligomerization-dependent binding leads to separate functional outcomes.
  • This represents a novel mechanism for regulating protein function and cellular processes.

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