Figure 2.

Physical interactions between Jaks and PKR. (A–D) The indicated cells were treated with either IFN-α2b or IFN-γ for the indicated time periods. Protein extracts were subjected to PKR immunoprecipitation (IP) followed by immunoblotting with the indicated antibodies. For the detection of tyrosine-phosphorylated Jak1, the phosphospecific pTyr1022/1023 antibody (A, panel a) or the phosphotyrosine 4G10 antibody (B, panel a) was used. The total levels of Jak1 or Tyk2 were detected by immunoblotting of whole-cell extracts (WCE; A,B, panel d; C,D, panel c). IFN, interferon; PKR, dsRNA-dependent protein kinase.