Phosphorylation of the plant encoded, double-stranded (dsRNA)-dependent protein kinase (pPKR) is significantly enhanced over basal levels during early phases of virus and viroid infection. It is unclear, however, if corresponding pPKR protein levels are affected by pathogenesis. We now show that virus infection differentially effects pPKR protein levels. Significantly, cytosolic associated pPKR protein levels are induced 3-5 fold compared to levels in extracts from mock inoculated leaves. However, ribosome-associated pPKR protein levels from virus infected tissues decreased approximately 4-fold relative to levels in extracts from mock inoculated tissues. Further, the level of cytosolic-associated pPKR capable of binding to dsRNA declined during early TMV infection events suggesting that vital dsRNA's bind to pPKR in the cytosol during initial phases of pathogenesis.
- DsRNA dependent protein kinase
- Protein phosphorylation
ASJC Scopus subject areas
- Plant Science