FIG 4.

Negative regulation of PABPs by HCMV proteins. 4E-BP, a translation inhibitor binding to eIF4E, regulates cellular translation initiation. HCMV excludes 4E-BP from the translation initiation complex to promote viral mRNA translation. HCMV UL38 disassociates 4E-BP from eIF4E by enhancing its phosphorylation through the mTORC1 signal, thus relieving the inhibition of translation initiations. UL38 also increases PABPs levels in the cytoplasm, assisting viral mRNA translations. HCMV UL69 excludes 4E-BP from cap-binding complex and PABPs by indirectly interacting with eIF4A.