HIV-1 reverse transcriptase is phosphorylated in vitro and in a cellular system

Int J Biochem Cell Biol. 1999 Dec;31(12):1443-52. doi: 10.1016/s1357-2725(99)00097-7.

Abstract

Phosphorylation modulates the activity of many proteins that interact with nucleic acids including DNA and RNA polymerases. The HIV-1 reverse transcriptase (RT) is essential during the replicative cycle of the HIV-1 virus. HIV-1 RT has several potential sites for phosphorylation that could regulate its activities. In this work, the phosphorylation of HIV-1 RT is examined in vitro and in vivo, to evaluate any role for this modification in regulating RT metabolism. Recombinant unphosphorylated HIV-1 RT heterodimer expressed in bacteria can be phosphorylated in vitro by several purified mammalian protein kinases. Seven kinases were tested, and five of these enzymes phosphorylated HIV-1 RT. Using an insect baculovirus expression system, the 66 kDa HIV-1 RT was also phosphorylated in vivo. However, HIV-1 RT immunoprecipitated from H9-lymphoma cells infected with HIV-1 showed negligible phosphorylation. Our results indicate that purified HIV-1 RT can be phosphorylated by several mammalian protein kinases in vitro and during expression in baculovirus infected insect cells.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Antibodies, Monoclonal
  • Cell Line
  • HIV Reverse Transcriptase / chemistry*
  • HIV Reverse Transcriptase / metabolism*
  • Kinetics
  • Molecular Sequence Data
  • Phosphates / metabolism
  • Phosphorus Radioisotopes
  • Phosphorylation
  • Protein Kinases / metabolism*
  • Recombinant Proteins / metabolism
  • Spodoptera
  • Substrate Specificity

Substances

  • Antibodies, Monoclonal
  • Phosphates
  • Phosphorus Radioisotopes
  • Recombinant Proteins
  • Protein Kinases
  • HIV Reverse Transcriptase