TRIM28 and infection: Unlike the DNA damage-inducing agent etoposide, IAV failed to trigger TRIM28 phosphorylation at Ser824, and functional inhibition of either ATM kinase (using KU55933) or the proteasome (using MG132 or lactacystin) was unable to prevent loss of posttranslationally modified TRIM28 during infection (SI Appendix, Fig. S1 C–G).