PKR and eIF2alpha: integration of kinase dimerization, activation, and substrate docking.
The antiviral RNA-dependent protein kinase, PKR, binds to viral double-stranded RNA in the cell and halts protein synthesis by phosphorylating the alpha subunit of the translation initiation factor eIF2. In this issue of Cell, two complementary papers Dar et al. (2005) and Dey et al. (2005) address the interaction between PKR and eIF2alpha. The structures of eIF2alpha bound to PKR reveal that PKR forms a dimer, the interface of which is essential for kinase activation, and demonstrate how this protein substrate docks to its kinase. The structures, coupled with mutagenesis analysis, also demonstrate how phosphorylation of the activation loop can allosterically couple two distal regions, the dimerization and substrate recognition interfaces.
Taylor
Susan S
SS
Howard Hughes Medical Institute, Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla 92093, USA.
Haste
Nina M
NM
Ghosh
Gourisankar
G
D000818:Animals; D019281:Dimerization; D015852:Eukaryotic Initiation Factor-2 / Q000737:chemistry* / Q000378:metabolism; D006801:Humans; D016297:Mutagenesis, Site-Directed; D010766:Phosphorylation; D011485:Protein Binding; D011487:Protein Conformation; D017433:Protein Structure, Secondary; D012330:RNA, Double-Stranded / Q000737:chemistry / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000737:chemistry; D019892:eIF-2 Kinase / Q000737:chemistry* / Q000378:metabolism
D015852:Eukaryotic Initiation Factor-2; D012330:RNA, Double-Stranded; D019892:eIF-2 Kinase