MX2 restricts HIV-1 and herpes simplex virus type 1 by forming cytoplasmic biomolecular condensates that mimic nuclear pore complexes

Human myxovirus resistance 2 (MX2) can potently restrict HIV-1 and herpesviruses at a post-entry step by a process that requires MX2 interaction with the capsids of these viruses. The involvement of other host cell factors in this process, however, remains poorly understood. Here, we mapped the proximity interactome of MX2 revealing strong enrichment of phenylalanine-glycine (FG)-rich proteins related to the nuclear pore complex as well as proteins that are part of cytoplasmic ribonucleoprotein granules. MX2 interacted with these proteins to form multiprotein cytoplasmic biomolecular condensates that were essential for its anti-HIV-1 and -herpes simplex virus-1 (HSV-1) activity. MX2 condensate formation required the disordered N-terminal region of MX2 and its dimerization. Incoming HIV-1 and HSV-1 capsids associated with MX2 at these dynamic cytoplasmic biomolecular condensates. Our results demonstrate that MX2 forms cytoplasmic condensates that act as nuclear pore decoys, which trap capsids and induce premature viral genome release, and thereby interfere with nuclear targeting of HIV-1 and HSV-1.