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Eukaryotic initiation factor 4GI is a poor substrate for HIV-1 proteinase

Petra Schlick1, Tim Skern

  • 1Institute for Medical Biochemistry, Division of Biochemistry, University of Vienna, Dr. Bohr-Gasse 9/3, A-1030 Vienna, Austria.

FEBS Letters
|October 10, 2002
PubMed

Insights

Foot-and-mouth disease virus proteinase (Lpro) rapidly cleaves eukaryotic initiation factor (eIF) 4GI. HIV-1 proteinase cleaves eIF4GI much slower, suggesting this cleavage may not inhibit protein synthesis during HIV-1 replication.

Area of Science:

  • Molecular Biology
  • Virology
  • Biochemistry

Background:

  • Eukaryotic initiation factor (eIF) 4GI is a key protein in cap-dependent translation initiation.
  • Picornaviruses are known to cleave eIF4GI during replication.
  • Recent observations indicate eIF4GI processing also occurs during HIV-1 replication.

Purpose of the Study:

  • To compare the efficiency of eIF4GI proteolysis by foot-and-mouth disease virus leader proteinase (Lpro) and HIV-1 proteinase (HIV-1pro).
  • To investigate the functional implications of eIF4GI cleavage in HIV-1 replication.

Main Methods:

  • In vitro translation assays using rabbit reticulocyte lysates.
  • Comparative analysis of eIF4GI cleavage kinetics by Lpro and HIV-1pro.
  • Quantification of proteinase concentrations and cleavage times.

Main Results:

  • Lpro demonstrated significantly higher efficiency in cleaving eIF4GI compared to HIV-1pro.
  • Lpro cleaved 50% of eIF4GI within 12 minutes at 0.1 nM.
  • HIV-1pro required 4 hours to achieve comparable cleavage at 2.66 nM.

Conclusions:

  • The proteolysis of eIF4GI by HIV-1pro is quantitatively different and less efficient than by Lpro.
  • The cleavage of eIF4GI during HIV-1 replication may not primarily serve to inhibit protein synthesis.

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