Figure 5.
The image contains three panels labeled A, B, and C. Panel A shows a Western blot analysis of P K R and e I F 2 alpha phosphorylation with varying levels of A l u d s R N A following poly I:C rechallenge. The blot displays bands for P-P K R, P K R, P-e I F 2 alpha, e I F 2 alpha, and beta-Actin across different concentrations of A l u d s R N A (0 microgram, 0.1 microgram, 1 microgram, and 10 microgram) with and without poly I:C rechallenge. Increasing A l u d s R N A alters the phosphorylation pattern of P K R and e I F 2 alpha in response to poly I:C. Total P K R and total e I F 2 alpha remain relatively constant, and beta-Actin serves as a loading control. Molecular weight markers (k D a) are shown at 75 and 37. Panel B presents a schematic illustration of the P K R titration model. It depicts how low versus high levels of endogenous d s R N A influence P K R dimerization. At low d s R N A levels, poly I:C promotes P K R dimer formation, leading to activation. At high endogenous d s R N A levels, P K R is sequestered into inactive complexes, reducing inducible dimerization upon poly I:C stimulation. Panel C shows cells with different levels of A l u d s R N A after poly (I:C) rechallenge, cross-linked with D S S, followed by S D S-P A G E and immunoblotting with anti-P K R and anti-P-P K R antibodies. The blots display bands for P K R and P-P K R across the same concentrations of A l u d s R N A.
High levels of Alu dsRNA attenuate PKR activation by titrating PKR dimerization. (A) Western blot analysis of PKR and eIF2α phosphorylation with varying levels of Alu dsRNA following poly I:C rechallenge. Data are representative of three independent experiments. (B) Schematic illustration of the PKR titration model. (C) Cells with different levels of Alu dsRNA after poly(I:C) rechallenge were cross-linked with DSS, followed by SDS-PAGE and immunoblotting with anti-PKR (left) and anti–P-PKR (right) antibodies. Data are representative of two independent experiments. Source data are available for this figure: SourceData F5.