Cytoplasmic ATR orchestrates PRRSV and EBOV replication organelle assembly via vimentin phosphorylation

Abstract

The ataxia telangiectasia-mutated and Rad3-related (ATR) kinase is a well-established master regulator of the DNA damage response and replication stress. In this study, we uncover an unexpected, conserved role of ATR in promoting the replication of two distinct RNA viruses—an arterivirus and a filovirus—through vimentin phosphorylation. Acute pharmacologic inhibition or knockdown of ATR robustly suppress viral replication and sharply reduce the formation of double-membrane vesicles and membrane-less condensates that serve as replication organelles (ROs) for these divergent viral classes. Notably, although ATR is recruited to cytoplasmic ROs throughout the viral life cycle, it acts specifically at the replication stage without affecting viral attachment, entry, or egress. We further show that ATR directly interacts with and phosphorylates vimentin within ROs, driving vimentin rearrangement and delineating RO boundaries. Mechanistically, ATR-dependent phosphorylation of vimentin at Ser459 is indispensable for RO formation during infection by both PRRSV and EBOV. Together, these findings reveal a conserved ATR–vimentin signaling axis that promotes RO biogenesis across diverse RNA viruses, defining a noncanonical function of cytoplasmic ATR in orchestrating the assembly of both membrane-bound and membrane-less replication compartments via vimentin phosphorylation.