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DRBP76, a double-stranded RNA-binding nuclear protein, is phosphorylated by the interferon-induced protein kinase,

R C Patel1, D J Vestal, Z Xu

  • 1Department of Molecular Biology, Lerner Research Institute, The Cleveland Clinic Foundation, Cleveland, Ohio 44195, USA.

The Journal of Biological Chemistry
|July 10, 1999
PubMed

Insights

Researchers identified DRBP76, a novel human double-stranded RNA-binding protein (DRBP). This protein interacts with PKR and is phosphorylated by it, suggesting PKR regulates DRBP76 cellular activities.

Area of Science:

  • Molecular Biology
  • Cell Biology
  • Virology

Background:

  • The interferon-induced protein kinase PKR is a key regulator of cellular responses to viral infection.
  • PKR belongs to a class of double-stranded RNA-binding proteins (DRBPs) characterized by a conserved dsRNA-binding motif.
  • Understanding the interactions and functions of DRBPs is crucial for deciphering cellular defense mechanisms.

Purpose of the Study:

  • To identify and characterize novel human double-stranded RNA-binding proteins (DRBPs).
  • To investigate the interaction between the newly identified DRBP76 and the protein kinase PKR.
  • To elucidate the potential regulatory role of PKR in the cellular functions of DRBP76.

Main Methods:

  • Purification and sequencing of DRBP76 from human cells.
  • Yeast two-hybrid screening using a mutant PKR as bait.
  • In vitro binding assays with dsRNA and PKR.
  • Analysis of epitope-tagged DRBP76 localization and co-immunoprecipitation with PKR.
  • In vitro phosphorylation assays using purified DRBP76 and PKR.

Main Results:

  • DRBP76 was identified as a novel human DRBP, also known as MPP4.
  • DRBP76 contains domains for dsRNA and PKR interaction and is localized in the nucleus.
  • DRBP76 interacts with PKR both in vitro and in vivo.
  • PKR phosphorylates DRBP76 in vitro, indicating a regulatory relationship.

Conclusions:

  • DRBP76 is a novel human double-stranded RNA-binding protein that interacts with PKR.
  • The interaction and phosphorylation of DRBP76 by PKR suggest a role for PKR in regulating DRBP76's cellular functions.
  • This discovery expands the known network of PKR interactions and potential cellular regulatory pathways.

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