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Functional Characterization of RING-Type E3 Ubiquitin Ligases In Vitro and In Planta
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Functional Characterization of RING-Type E3 Ubiquitin Ligases In Vitro and In Planta

Published on: December 5, 2019

Ubiquitin ligase activities of Bombyx mori nucleopolyhedrovirus RING finger proteins

Noriko Imai1, Noriyuki Matsuda, Keiji Tanaka

  • 1Laboratory of Molecular Entomology and Baculovirology, Wako, Japan.

Journal of Virology
|December 28, 2002
PubMed

Insights

Bombyx mori nucleopolyhedrovirus (BmNPV) RING finger proteins IAP2, IE2, and PE38 exhibit ubiquitin-ligase (E3) activity. This suggests their crucial role in viral infection processes.

Area of Science:

  • Virology
  • Molecular Biology
  • Biochemistry

Background:

  • The Bombyx mori nucleopolyhedrovirus (BmNPV) genome encodes six putative RING finger proteins.
  • Many RING finger proteins possess ubiquitin-ligase (E3) activity, a key enzymatic function in protein regulation.

Purpose of the Study:

  • To investigate the E3 enzymatic activity of BmNPV RING finger proteins.
  • To determine if these viral proteins function as E3 enzymes during infection.

Main Methods:

  • In vitro ubiquitination assays using rabbit reticulocyte lysates.
  • Expression of BmNPV RING finger proteins fused with maltose-binding protein (MBP).
  • Mutational analysis of the RING finger motif.

Main Results:

  • Four BmNPV RING finger proteins (IAP2, IE2, PE38, CG30) were polyubiquitinated in vitro with zinc.
  • MBP-IAP2, MBP-IE2, and MBP-PE38 reconstituted ubiquitination activity with Ubc4/5 enzymes.
  • Ubiquitination activity of MBP-IAP2, MBP-IE2, and MBP-PE38 was dependent on the RING finger motif.

Conclusions:

  • The BmNPV proteins IAP2, IE2, and PE38 likely function as E3 ubiquitin ligases.
  • These findings provide insights into the molecular mechanisms of BmNPV infection.

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