May modulate tight-junctions functions of infected cells through interactions with PDZ proteins. E4 ORF1 has ben show for Adenovirus 9 to interact with protein involved in tight junction regulation. May play a role in mTOR activation by activating PI3-kinase, thus overriding cellular checkpoint for translation. May interact with host PDZ proteins through the PDZ domain binding motif (PBM), namely host DLG1, PATJ AND TJP2. Belongs to the adenoviridae E4-ORF1 family.