Phosphorylation Time‐Course Study of the Response during Adenovirus Type 2 Infection

PTMs such as phosphorylations are usually involved in signal transduction pathways. To investigate the temporal dynamics of phosphoproteome changes upon viral infection, a model system of IMR‐90 cells infected with human adenovirus type 2 (Ad2) is used in a time‐course quantitative analysis combining titanium dioxide (TiO₂) particle enrichment and SILAC‐MS. Quantitative data from 1552 phosphorylated sites clustered the highly altered phosphorylated sites to the signaling by rho family GTPases, the actin cytoskeleton signaling, and the cAMP‐dependent protein kinase A signaling pathways. Their activation is especially pronounced at early time post‐infection. Changes of several phosphorylated sites involved in the glycolysis pathway, related to the activation of the Warburg effect, point at virus‐induced energy production. For Ad2 proteins, 32 novel phosphorylation sites are identified and as many as 52 phosphorylated sites on 17 different Ad2 proteins are quantified, most of them at late time post‐infection. Kinase predictions highlighted activation of PKA, CDK1/2, MAPK, and CKII. Overlaps of kinase motif sequences for viral and human proteins are observed, stressing the importance of phosphorylation during Ad2 infection.