Polyanion regulation of the plant-encoded double-stranded RNA- dependent protein kinase (pPKR)

J. O. Langland, L. A. Langland, D. A. Roth

Research output: Contribution to journalArticlepeer-review

3 Scopus citations


The only known activators of the plant encoded, double- stranded RNA dependent protein kinase (pPKR) are dsRNA's and single-stranded RNA with extensive intramolecular base pairing such as viroid RNAs. DNA, DNA-RNA hybrids and most single stranded RNA's do not stimulate phosphorylation. However, the in vivo phosphorylation of pPKR in the cytoplasm of healthy cells suggests that alternate activators may be present. Here we show that select polyanions including heparin and dextran sulfate, stimulate pPKR phosphorylation in a concentration dependent fashion. Further, pPKR specifically binds to heparin-agarose indicating the presence of a polyanion binding domain. The functional significance of polyanion regulation of pPKR may be suggested by the inhibition of in vitro translation of brome mosaic virus RNA in wheat germ extracts in the presence of heparin. These studies further establish the analogy between pPKR and the mammalian interferon- induced, dsRNA dependent protein kinase, PKR, and present possibilities for the activation of pPKR in healthy cells.

Original languageEnglish (US)
Pages (from-to)521-526
Number of pages6
JournalPlant Physiology and Biochemistry
Issue number4
StatePublished - Jan 1 1996
Externally publishedYes


  • PKR
  • Protein phosphorylation
  • RNA
  • polyanion regulation

ASJC Scopus subject areas

  • Physiology
  • Genetics
  • Plant Science


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