Protein that inhibits host translation while promoting late viral translation by ribosome shunting. Blocks host cap-dependent translation by binding to eIF4G, displacing MKNK1 from cap initiation complexes and preventing EIF4E phosphorylation. Binds to the tripartite leader sequence of viral late mRNAs and recruits host eIF4G, PABPC1/poly-A binding protein and 40S ribosomes subunits on viral mRNAs, allowing ribosome shunting and efficient translation of late viral mRNAs even though conventional translation via ribosome scanning from the cap has been shut off in the host cell. During assembly, acts as a chaperone protein that helps hexon proteins assembly into trimers. Monomer. Interacts with hexon protein; this interaction allows chaperoning and trimerization of hexon proteins. Interacts (via N-terminus) with host initiation factor EIF4G (via C-terminus). Interacts (via RRM domain) with viral mRNAs that contain the tripartite leader; this interaction allows ribosome shunting and expression of viral late mRNAs. Expressed in the late phase of the viral replicative cycle. Might be cleaved by the viral protease. Phosphorylated. Tyrosine phosphorylation enhances preferential binding to tripartite leader mRNAs and allows ribosome shunting. Methylated. Asymmetric dimethylation by host PRMT1 of the Arg/Gly-rich region may regulate shutoff protein binding to hexon and promote the capsid assembly in the nucleus. All late proteins expressed from the major late promoter are produced by alternative splicing and alternative polyadenylation of the same gene giving rise to non-overlapping ORFs. A leader sequence is present in the N-terminus of all these mRNAs and is recognized by the viral shutoff protein to provide expression although conventional translation via ribosome scanning from the cap has been shut off in the host cell. Belongs to the adenoviridae shutoff protein family.