Dataset Information

A new double-stranded RNA-binding protein that interacts with PKR.

ABSTRACT: We have identified a 74 kDa double-stranded (ds)RNA-binding protein that shares extensive homology with the mouse spermatid perinuclear RNA-binding (Spnr) protein. p74 contains two dsRNA-binding motifs (dsRBMs) that are essential for preferential binding to dsRNA. Previously, dsRNA-binding proteins were shown to undergo homo- and heterodimerization, raising the possibility that regulation of activity could be controlled by interactions between different family members. Homodimerization is required to activate the dsRNA-dependent protein kinase PKR, whereas hetero-dimerization between PKR and other dsRNA-binding proteins can inhibit kinase activity. We have found that p74 also interacts with PKR, both the wild-type enzyme and a catalytically defective mutant (K296R). While co-expression of p74 and wild-type PKR in the yeast Saccharomyces cerevisiae did not alter PKR activity, co-expression of p74 and the catalytically defective K296R mutant surprisingly resulted in abnormal morphology and cell death in transformants that maintained a high level of p74 expression. These transformants could be rescued by overexpression of the alpha-subunit of wild-type eukaryotic translation initiation factor 2 (eIF2alpha), one of the known substrates for PKR. We hypothesize that competing heterodimers between p74-K296R PKR and eIF2alpha-K296R PKR may control cell growth such that stabilization of the p74-K296R PKR heterodimer induces abnormal morphology and cell death.

SUBMITTER: Coolidge CJ

PROVIDER: S-EPMC111047 | biostudies-literature | 2000 Mar

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

A new double-stranded RNA-binding protein that interacts with PKR.

Coolidge C J CJ Patton J G JG

Nucleic acids research 20000301 6

We have identified a 74 kDa double-stranded (ds)RNA-binding protein that shares extensive homology with the mouse spermatid perinuclear RNA-binding (Spnr) protein. p74 contains two dsRNA-binding motifs (dsRBMs) that are essential for preferential binding to dsRNA. Previously, dsRNA-binding proteins were shown to undergo homo- and heterodimerization, raising the possibility that regulation of activity could be controlled by interactions between different family members. Homodimerization is requir ...[more]

PMID: 10684936

Similar Datasets

Project description:BackgroundDouble-stranded (ds) RNA, generated during viral infection, binds and activates the mammalian anti-viral protein kinase PKR, which phosphorylates the translation initiation factor eIF2alpha leading to the general inhibition of protein synthesis. Although PKR-like activity has been described in fish cells, the responsible enzymes eluded molecular characterization until the recent discovery of goldfish and zebrafish PKZ, which contain Z-DNA-binding domains instead of dsRNA-binding domains (dsRBDs). Fish and amphibian PKR genes have not been described so far.ResultsHere we report the cloning and identification of 13 PKR genes from 8 teleost fish and amphibian species, including zebrafish, demonstrating the coexistence of PKR and PKZ in this latter species. Analyses of their genomic organization revealed up to three tandemly arrayed PKR genes, which are arranged in head-to-tail orientation. At least five duplications occurred independently in fish and amphibian lineages. Phylogenetic analyses reveal that the kinase domains of fish PKR genes are more closely related to those of fish PKZ than to the PKR kinase domains of other vertebrate species. The duplication leading to fish PKR and PKZ genes occurred early during teleost fish evolution after the divergence of the tetrapod lineage. While two dsRBDs are found in mammalian and amphibian PKR, one, two or three dsRBDs are present in fish PKR. In zebrafish, both PKR and PKZ were strongly upregulated after immunostimulation with some tissue-specific expression differences. Using genetic and biochemical assays we demonstrate that both zebrafish PKR and PKZ can phosphorylate eIF2alpha in yeast.ConclusionConsidering the important role for PKR in host defense against viruses, the independent duplication and fixation of PKR genes in different lineages probably provided selective advantages by leading to the recognition of an extended spectrum of viral nucleic acid structures, including both dsRNA and Z-DNA/RNA, and perhaps by altering sensitivity to viral PKR inhibitors. Further implications of our findings for the evolution of the PKR family and for studying PKR/PKZ interactions with viral gene products and their roles in viral infections are discussed.

Dataset Information

A new double-stranded RNA-binding protein that interacts with PKR.

Publications

A new double-stranded RNA-binding protein that interacts with PKR.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets